This PDF file contains the front matter associated with SPIE Proceedings Volume 6423, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Hydrothermal method was used to synthesize (K,Na)(Nb,Ta)O₃ powders with the addition of isopropanol. The phases of the obtained powders were identified by XRD. The morphology and particle size were observed by FE-SEM. The presence of water and organic group were determined by (FTIR) spectroscopy. The results indicate that the pure (K,Na)(Nb,Ta)O₃ powders with perovskite structure and fine particles were successfully synthesized by hydrothermal method at 240 °C for 8 hours with the addition of isopropanol. With the increase of Ta content in the starting materials, the Ta/(Ta+Nb) molar ratios increased in the products. With increase of K content in the starting solutions, the morphology of the obtained crystals varied, and the K content in the products increased. The K/(K+Na) molar ratio in the products is lower than that in the staring solutions. The specimen with the composition of K_0.22Na_0.78NbO₃ exhibited the highest piezoelectric constant of d₃₃ = 120 pC N^-1.

Piezocomposites are a popular class of smart material that are used in a wide range of advanced engineering applications. A common form is the 1-3 piezocomposites used in underwater hydrophones and other acoustical applications. It is important to know the coupled electromechanical behaviour of a piezoelectric fiber-matrix system to design composites with enhanced properties. This paper is an attempt to obtain a fundamental understanding of the fiber-matrix interaction in a 1-3 piezocomposite. The case of a long cylindrical piezoelectric fiber embedded in a transversely isotropic elastic matrix with electrically impermeable conditions along the fiber-matrix interface is considered. The fiber is perfectly bonded to the medium and subjected to a uniformly distributed axial load over its cross-section. General solutions corresponding to an infinite piezoelectric fiber with a vertical body force and an infinite transversely isotropic elastic medium with a cylindrical hole are derived by using Fourier integral transforms. These general solutions are used to solve the load transfer boundary-value problem. Numerical results for the axial force, electric field and displacements are examined to understand the load diffusion and electromechanical interaction in a fiber-matrix system. In addition, shear stress along the interface is also studied for various fiber-matrix systems to understand the interfacial behaviour.

Novel damping materials composed of PZT and bromobutyl rubber with different amount of acetylene carbon in system were prepared and the damping property and piezoelectric property of composites were studied. The detection results indicated that, the damping factors of materials increase with the increase of carbon amount in system until the mass fraction of carbon reached 8%. And the polarization temperatures and amount of PZT both improved the damping properties of materials. Also the piezoelectric constant increased with that of polarization temperatures.

Lead zirconate titanate/IPN piezoelectric composites with 1-3 connectivity consisting in Interpenetrating Polymer Networks (IPN) matrix and Lead Zirconate Titanate (PZT) fibers with length of 50um fabricated by the sol-gel route were prepared through solution mixing method. The process of PZT gel fibers formed and the changes of crystal grain sizes during thermal treatment were traced and analyzed by TG-DTA and XRD methods. Then the composites were polarized at 100°C for 45min. The micro patterns of PZT fibers and PZT fibers/IPN composites were observed by polarizing microscopes. The electrical properties studies of 1-3 composites in function of temperatures and frequencies indicate that, the values of electrical parameters of composites detected were all smaller than that PZT and larger than that IPN matrix. Also, the polarized process and polarized mechanism of PZT fiber/IPN composites were discussed in view of dielectric constant results detected. And the detection results of electrical properties show consistency of the theoretical analysis results of composites.

A novel silicon micromachined hinged high-g piezoresistive accelerometer with wide bandwidth is presented. The sensitivity of this accelerometer can be improved while maintaining a high resonance frequency. Based on the simulation of the finite element method, design parameters are obtained for a natural resonance frequency of 573kHz for a large range of 200,000g. The high-g accelerometer is fabricated by advanced silicon bulk micromachining technology. By using a dropping-hammer testing system, characterization measurements show a sensitivity of 0.502μV/g for a 30646g shock acceleration under the 5V excitation.

The effects of geometry on the energy dissipation induced by thermoelastic damping in MEMS resonators are investigated numerically using a finite element formulation. The perturbation analysis is applied to derive a linear eigenvalue equation for the exponentially decaying rate of the mechanical oscillation. The analysis also involves a Fourier method that reduces the dimensionality of the problem and considerably improves the computational efficiency. The method is first validated by comparing the two-dimensional model to the existing analytical solutions for a simply supported beam system, and then it is extended to a three-dimensional axisymmetric geometry to obtain the energy loss as a function of the geometric parameters in a silicon ring resonator. The computational results reveal that there is a peak value for the resonant frequency when the radial width of the ring varies. In addition, the quality factor (Q-factor) decreases with the radial width as a monotonic function.

This paper presents a bulk micromachined gyroscope with fully symmetric and doubly decoupled structure. The fully symmetric structure enables matched resonant frequencies of the drive and sense modes. The doubly decoupled mechanism, which reduces the cross-coupling and the quadrature error, is realized by independent and folded suspensions for restricting the drive and sense moveable fingers' degree of freedom (DOF). Additionally, the gyroscope has large quality factors even operating at atmospheric pressure, which is designed by utilizing slide film damping effects in drive and sense modes. Simulation results show that the resonant frequency for the drive and sense modes are 2776Hz and 2777Hz, respectively, and the cross-coupling is less than 0.2%. The gyroscope chip is fabricated by silicon-glass anodic bonding and deep reactive ion etch (DRIE) technology. The fabricated gyroscope has a structure thickness of 80 μm and a whole chip size of 5.5×5.5 mm². The gyroscope has a static sense capacitance of 3.5 pF with minimum capacitive gaps of 4 μm. The measured resonant frequency with damping is 2581 Hz with the quality factor of 195 at atmospheric pressure.

The design, numerical simulation and fabrication process of a silicon micro flat heat pipe with axially micromachining triangle grooves are discussed. In this paper the structure of a silicon micro flat heat pipe is presented firstly. Then numerical simulation is undertaken to evaluate the thermal performance of micro flat heat pipe. Using MATLAB a one-dimensional model is developed and solved numerically to investigate the flow of liquid and vapor in triangle grooves. The effect of interfacial and vapor shear stress is considered in the model. The results obtained from this simulation contain axial variation of pressure difference between vapor and liquid, velocity of liquid and vapor and film thickness. In addition maximum heat transport capacity of MHP is calculated. The results predicted by the model are compared with the published results in literature and show good agreement. These numerical results are used to determine the structural parameters of final prototypes. Finally a silicon/methanol prototype was fabricated to demonstrate the feasibility of heat spreading using this type of MHP. The MHP grooves capped by a glass wafer were fabricated by using bulk micromachining and anode bonding techniques. Detailed fabrication process of a silicon micro flat heat pipe with axial triangle grooves is presented.

This paper reports the fabrication of nanocrystalline Strontium Barium Bismuth Titanate Sr_1-xBa_xBi₄Ti₄O₁₅ (SBBT) thin films for piezoelectric pressure sensors. The SBBT films and capacitance devices with structure of Al/TiO₂/SBBT/TiO₂/RuO₂/SiO₂/Si were fabricated using sol-gel technique. Different nanostructures of the films were prepared with un-annealed condition as well as after annealing at three temperatures; 400, 500 and 600^oC, in air for 2 minutes. The nanostructure of SBBT thin films have been systematically studied by XRD, AFM, SEM and dielectric constant. For the sensor device measurement, the SBBT thin film pressure sensors were tested by pneumatic loading method at pressure range between 0 to 450 kPa. It was found that the sensing properties of the films were affected by the nanostructure of the films. It was shown that there was a linear relationship between the crystallization, grains size and dielectric properties with the sensing response of the film towards pressure. The film with higher crystallization, grains size and dielectric properties demonstrates better sensitivity and repeatability compared to others. The correlation between nanostructure of the SBBT films and the piezoelectric pressure sensing properties will be discussed.

Modulated wrinkle patterns could be yield on a gold thin film covering an elastomeric polymer with the following simple process. The simple, efficient ultra-precision turning technique was used to prepare patterned surface of Al samples, which served as a hard master to replicate reverse patterns on the elastomeric polydimethylsiloxane (PDMS) surface by replica molding. The surface patterns in PDMS have the irregular section, different from those fabricated by optical lithography. And then a gold thin film was deposited by ion sputtering onto the patterned surface of PDMS substrates. Due to great difference in heat expansion coefficient between the metal and elastomeric polymer, modulated wrinkle patterns spontaneously appeared on the gold thin film, including stripe and herringbone. When the wavelength of the wrinkle pattern is approximately close to or more than height and width of the microstructures on the PDMS substrates, the herringbone wrinkles appear and entirely overlay the grating pattern; and otherwise the stripe pattern occurred on patterned surface of PDMS substrates and distributed perpendicularly to the step. Due to obvious difference in metal film depth, modulated wrinkle patterns, including regular striped and herringbone pattern, could be generated on gold thin films deposited onto PDMS surface.

This study investigates the crystallization and compositional changes in amorphous silicon nitride (SiN_x) thin films induced by heat treatment at elevated temperatures in air. The films were synthesized by plasma enhanced chemical vapor deposition (PECVD) method. It is found that PECVD SiN_x films crystallize at 1148 K, which is much lower than that reported in the literature for silicon nitride powders and thin films. The crystallization occurs in the form of small silicon nitride crystal clusters scattered in the film, while the rest of the film partially oxidizes to amorphous silicon oxynitride. The crystallized silicon nitride is found to be α-Si₃N₄.

The microstructure and mechanical properties of interface between GH4133 substrate and laser cladding were investigated experimentally. It was found that the process variables for laser cladding can result in the formation of incomplete fusion between the cladding layer and substrate or reheat cracking along the grain boundary in the coarse grain zone of the heat-affected zone (HAZ) during ageing treatment. The SEM and EDS analysis demonstrates that the chemical compositions in the crack and substrate are very similar and there is not precipitation in the crack. Therefore, the reheat cracking has nothing to do with liquid film on the grain boundaries, the possible cause of the formation of reheat cracking is that the plastic deformation caused by residual stress formed during thermal cycle of laser cladding concentrates on the coarse grain boundary in HAZ because precipitations precipitating in the grain during ageing treatment strengthen grain. The laser cladding layer with integrated melt interface and without reheat cracking can be obtained by optimizing laser power, scanning velocity and powder thickness. The experimental results of microhardness have shown that the microhardness of laser cladding layer is the same with that of GH4133 base metal after ageing treatment, thus the properties of the clad layer and the substrate are homogeneous.

The reconstruction of peripheral nerve defects over a short distance (10-20mm) could benefit from the development of novel biomaterials. Bio-degradable and bio-compatible materials are being pursued to replace the currently used nerve autografts. We hypothesize that physical properties, particularly surface texture, could have substantial effects on the hydrophilicity of some synthetic polymers and subsequently the compatibility of them with cells. In this study, poly (ε-caprolactone) (PCL) films have been cast using four solvents from different chemical families and evaluated for their suitability and potential use as a nerve conduit substratum. The following solvents: dichloromethane (DCM, Halocarbon), methyl acetate (MA, Ester), tetrahydrofuran (THF, Ether) and acetic acid (AA, organic acid) were used to produce PCL films. The physical properties of these PCL films, average surface roughness (Ra) and wettability were measured. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were applied to obtain information on the surface texture. Motor neuron-like NG108-15 cells were used as a model to evaluate the biocompatibility of the films. It was found that same polymer when processed using different solvents could produce materials with markedly different physical and biochemical properties. Importantly, all PCL films were supportive for the growth and differentiation of NG108-15 cells.

Growth and magnetism of thin iron films on the surfaces Si(100), Si(111) and Si(111)-4° are studied by in situ SMOKE and ex-situ AFM methods. Comparison of growth modes for slow and ultra-fast deposition is given. Design of the pulse-type ultra-fast evaporator is described.

Carbon nanotubes (CNTs) have attracted broad attentions for developing innovative nanocomposites due to their exceptional properties. However, the success of developing nanocomposites is largely dependent on material processing. Authors' group has developed an innovative electrochemical co-deposition form synthesis of CNT reinforced metallic (Ni). Results indicate that the yield and ultimate strength of the as-deposited pure nickel are found to be about 350MPa and 625MPa, respectively, which are comparable to the reported data. However, it demonstrates that the yield strength and ultimate strength of Ni/MWCNT composite are about 1,290MPa and 1,700MPa, respectively. In other word, the ultimate strength of Ni/MWCNT nanocomposite is about 270% higher than that of pure nickel. Authors believe the largely increased mechanical strength of Ni/CNT nanocomposite is attributed to the novel fabrication that high temperature associated degradation problems in metallic composite processing such as diffusion, chemical reaction and mismatch of coefficient of thermal expansion (CTE) are eliminated.

Structural Health Monitoring and damage identification are playing an important role in civil engineering in recent two decades. Much more efforts to Structural heath monitoring and damage detection had been made in worldwide range. In general, local and global methods were used to detect damage. For local methods, the potential damage region must be prior to know; but for global methods, comparing the structural dynamic parameters under damaged and undamaged state, damage can be identified and located. That is to say, when using global method to identify damage the parameters of intact structure are regarded as structural health baseline. But generally, the responses of damaged and intact structure were not obtained under the same noise level. Thus, new health baseline is defined and constructed in this paper.

The wind turbine industry is the fastest growing market area for the use of composite materials. Fiber Bragg grating sensor can be used to monitor the mechanical behavior of composite wind blade. The internal strain of composite wind blade during a constant stress amplitude fatigue testing process was monitored with fiber Bragg gratings sensors. FBG sensors can not only be embedded in composite structures to detect fatigue damage, but also have excellent durability compared with other sensors such as electric strain gauges. After 1 million cycles, the FBG sensors can still keep good sensibility. FBGs as a fatigue indicator are a novel sensor to monitor, evaluate and give crash alert for the health state of composite wind blades during their whole service life.

Piezoelectric materials have direct and converse piezoelectric effects and can serve as actuators and/or sensors. A piezoelectric impedance technique for crack monitoring in concrete structures is addressed in this paper, which use the electromechanical coupling property of piezoelectric materials. The basic principle of the technique is that by measuring the electrical impedance of piezoelectric ceramic sheets (PZT) bonded to the surface of host structure, the changes in structural mechanical impedance resulted from the presence of crack damage are monitored because the electrical impedance of PZT is directly related to the mechanical impedance of host structure. The main features of the technique are that it is not based on any physical models and its high frequency characteristics. An experimental study on crack monitoring of concrete beams was implemented based on the piezoelectric impedance technique. In this experiment, the electrical admittances (inverse of electrical impedances) of PZT were measured when the host beam was suffering from cracks with variable depth. Subsequently, a damage index, the root-mean-square deviation of real admittance (RMSDR) was presented, by which the locations and extents of concrete cracks were determined. It was found experimentally that the piezoelectric impedance technique for crack monitoring in concrete beam was quite effective and sensitive, which indicated its favorable application views in civil infrastructure systems.

Electro-Active Paper(EAPap) actuator materials based on cellulose has been discovered as a smart material that has merits in terms of low voltage operation, lightweight, dryness, low power consumption, bio-degradability, abundance and low price. Since EAPap material requires low power consumption, a remotely driven actuator has been proposed by using microwave power transmission. This concept is attractive for many biomimetic systems such as crawling micro-insect robots, flying objects like dragon fly, and smart wall papers. However, the actuation performance of EAPap is sensitive to humidity. Thus, in this paper, a new EAPap that is less sensitive to humidity is studied. The fabrication of EAPap is explained and the actuations are shown with actuating voltage, frequency, humidity level and time. The fabrication process includes dissolving cellulose fibers, eliminating solvent and Li ions with DI (deionized) water and IPA (Isopropyl alcohol) mixture, washing with water, drying and gold coating. Morphology of the fabricated EAPap is analyzed by taking scanning electron microscope images and X-ray diffractogram. The actuator performance is tested in terms of bending displacement with frequency and humidity level.

Conducting polymers (CPs), such as polypyrrole, polythiophene and polyaniline, are unique in that they have switchable properties due to their two or more mechanically stable oxidation state. Thus, their films or coatings can be easily switched by the application of small voltage and current to change volume during their electrochemical redox process. In particular, polypyrrole (PPy) has been studied most extensively because of its high electrical conductivity and good environmental stability under ambient condition. In this work, we have studied a new CP actuator, fully polymeric, assembled with two PPy film electrodes and a solid polymer electrolyte (SPE), polyurethane/Mg(ClO₄)₂. Polyurethanes (PUs) were synthesized from 4,4'-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and three types of polyols, poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and PPG-block-PEG-block-PPG (PPG-co-PEG). The chemical polymerization of PPy by immersion in Py monomer aqueous solution and oxidant aqueous solution is an adequate method to prepare PU/PPy composite film as actuator. To find the proper thickness of PPy coating layer for actuation, we measured the displacement of actuators according to the thickness of PPy coating layer. And, the displacement of all actuators was discussed in connection with the properties of SPE and PPy. All the results obtained in this work show the feasibility of electrochemomechanical devices based on PPy and SPE film able to work in air.

Concrete-filled fiber-reinforced polymer (FRP) tube is a type of newly developed structural column. It behaves brittle failure at its peak strength, and so the health monitoring on the hoop strain of the FRP tube is essential for the life cycle safety of the structure. Herein, three types of FRP tubes including 5-ply tube, 2-ply tube with local reinforcement and FRP-steel composite tube were embedded with the optic fiber Bragg grating (FBG) strain sensors in the inter-ply of FRP or the interface between FRP and steel in the middle height and the hoop direction. The compressive behaviors of the concrete-filled FRP tubes were experimentally studied. The hoop strains of the FRP tubes were recorded in real time using the embedded FBG strain sensors as well as the embedded or surface electric resistance strain gauges. Results indicated that the FBG strain sensors can faithfully record the hoop strains of the FRP tubes in compression as compared with the embedded or surface electric resistance strain gauges, and the strains recorded can reach more than με.

A novel stable and high-sensitivity fiber strain sensor based on optical pulse correlation measurement and birefringence compensation approach is proposed. Both the differential correlation measurement and the double-path monitoring established in the birefringence compensation process provide the possibility of high-sensitivity sensing. By using the optical correlation strain sensing system, the strain characteristic of single-mode fiber and dispersion-shifted fiber with different coating materials at different length are investigated. The extension coefficients of the monitoring fibers are estimated. The results indicated that single-mode fiber with FRPE coating has the highest strain sensitivity in this experiment, which is potential to be used in the field measurement in future.

Shape memory alloys (SMAs) are a relatively new class of functional materials, exhibiting special thermo-mechanical behaviors, such as shape memory effect and superelasticity, which enables their applications in seismic engineering as energy dissipation devices. This paper investigates the properties of superelastic shape memory alloys and highlights the influence of strain rate on superelastic behavior under various strain amplitudes by cyclic tensile tests on NiTi SMA wires. A novel constitutive equation is proposed to describe the strain-rate dependent hysterestic behavior of superelastic SMAs at different strain levels. This development is based on the Graesser and Cozzarelli's model, which has the advantage of simplicity. To verify the effectiveness of the proposed constitutive equation, experiments on a superelastic NiTi wire with different strain rates and strain levels are conducted. Experimental results and the numerical simulation based on the proposal constitutive equation are in close agreement. The results in this paper are useful for future design of superelatic SMA-based energy dissipation devices for seismic protection of structures.

NiTi wire was anodized in phosphoric acid, diluted hydrogen fluoride, and fluoric ions containing non-aqueous electrolytes. Surface morphologies and compositions of modified NiTi wires were characterized by using field-emission scanning electron microscopic (FESEM) equipped with an energy dispersive spectroscopy (EDS). The formation of oxides with reduced nickel element was observed on NiTi wires anodized in aqueous solution. Nano-roughness with lower surface hardness, compared to smooth surface formed in phosphoric acid, was obtained by anodization in hydrogen fluoride. After treatment in aqueous solution, corrosion resistance was improved as indicated by linear sweep voltammetry test in 0.9 % NaCl solution at room temperature. Uniform hydroxyapatite film on NiTi and anodized NiTi was obtained by electrodeposition method.

Aside from using SMA wires under uniaxial loading as the actuation elements, some researchers have developed a number of models that can simulate multiaxial behavior under tension-torsion combined loading or full three-dimensional loading. But there are many difficulties in identifying the model parameters and applying the model to application. Moreover, most research has focused on tubular materials, although SMA rods have the nonlinear stress distributions through radial direction. In this work, a constitutive model that can describe the pseudoelastic and shape memory behavior of a circular SMA rod is suggested. To describe the material behavior at the transformation region, the plastic flow rule is used and it is assumed that the transformation occurs in accordance with J'₂, J'₃ combined yield criterion. Brinson's model is used for the martensite transformation kinetics. The boundary layer of the elastic region and the transformation region were assumed to monotonically decrease from the outer radius, and the thermal expansion effect was not considered. Numerical analysis and experiments about pseudoelasticity and shape memory behavior were conducted. It can be seen that the suggested model is in good accord with the experimental results. Because the proposed model has fewer parameters than three-dimensional models or thermomechanical models, it can be easily used for practical engineering purposes.

In this paper, the vibration damping capacities of cement-based matrix with some additions of multi-walled carbon nanotubes (MWNTs) are investigated with free vibration testing method in an elastic system. The experimental results show that there are positive effects on the critical damping ratio ζ of the cement-based matrix with small amount MWNTs additions. The nanotubes increase the damping ratios (ζ) of the MWNTs reinforced cement composites due to the contribution of excellent frictions among multiple inter-tubes and multi-walled carbon nanotubes-matrix large interface area to damping. The flexural and compressive strength tests of those are subsequently implemented. Results indicate that the nanotubes has the reinforcing function to cement on the flexural strength in some degree, while has the negative impact on its compressive strength.

Atmospheric microplasma was produced in a scanning electron microscope (SEM) chamber for synthesizing carbon nanomaterials. The SEM observation is convenient for both adjusting the gap length and observing the electrode surface before and after experiments. After adjusting the gap length, the electrodes were housed in a small removable gas cell equipped in the SEM chamber and CH₄ discharge gas was introduced into the gas cell. It was found that the discharge was pulsated automatically due to slow discharge through a large ballast resistor and fast discharge through gas breakdown even though a DC voltage was applied. The peak pulse current density was almost 60 kA/cm², the peak power density in the microplasma volume was approximately 555 MW/cm³, and the pulse width was 10 ns typically. Spherical and nanotube like carbon nanomaterials was found on the cathode surface after the microplasma discharging for 1-5 seconds. With the discharge time increases, the spherical substance changes into nanotube like carbon nanomaterials.

This paper reports on further research into the structure and properties of the cleaved surfaces of InP, using vacuum cleavage luminescence detection methods. A detailed study is described on cleavage luminescence from InP both in vacuum and in ambient. Two cleavage luminescence signals were found, one at 1.25eV (bulk band gap radiation), called the A-signal, and the other at 1.9±0.3eV (surface defects signal), called the C-signal. All the signals have very short duration - about 10μs. The true duration could be much less. The signal C occurred both in vacuum and in air but the signal A was quenched in air.

Very thin shells, shell-membrane and membrane structures offer high actuator authority for controlling their behaviour. On the other side, special care has to be taken for proper material and structural characterisation and its interaction with the actuators. In the paper different types of actuators are discussed in the context of precision shell-membrane space reflectors. For actuation, emphasis is given on piezo-ceramics and electro-active polymers. Special integration, modelling and testing techniques for smart fibre reinforced shell-membranes and membranes are addressed.

There is growing interest in biomimetic motions by employing ionic polymer-metal composites (IPMCs) as the candidates for the fabrication of artificial muscle. However, the membrane materials currently used in IPMC actuators have been limited to a few commercially available perfluorinated ionic polymers, such as Nafion, and they suffer from several shortcomings among which their high cost presents a major obstacle for wide application. With excellent proton conductivity and high water uptake capacity, commercially available Sulfonated poly (styrene-ethylene-butylene-styrene) (SEBS) of low cost has been investigated for many years as a fuel cell membrane. Herein, we report the preparation of a novel IPMC actuator based on the sulfonated SEBS (SSEBS) membrane. The platinum electrodes of the SEBS actuators were obtained with electroless plating procedure, and the cation exchange with lithium was performed by soaking the composite membranes into a 1.5N LiCl solution. The surface and cross-sectional morphologies of the SSEBS actuators were observed by using scanning electron microscopy (SEM), which revealed that the platinum layer up to 8µm was deposited on the top and bottom surfaces of the SSEBS membrane. The electromechanical bending responses were investigated under alternating current excitations with various driving frequencies and voltage amplitudes, which showed high electrical strains under sinusoidal signal. The effect of the membrane thickness on the performance of the actuators was also addressed in this presentation. This kind of IPMC has great potentials for the applications in biomimetic sensors and actuators, which can be utilized to mimic the locomotion of fish and insects and can be applied to micro-robots and bio-medical devices as well.

Light-induce bending of photochromic LCEs is a newly found phenomenon, with potential applications such as artificial muscles, nano actuators and remote-controllable implements. To simulate this, light-induced bending models of straight and curved beams can be derived from the simple beam theory. The effect of the light is substituted as an effective bending moment. Several examples, with different approximations, boundary conditions, under uniform or nonuniform illuminations, are demonstrated to calculate the curvature, the restraining force or the deflection. Especially, under weak light intensities and low temperature, the analytical expression of the curvature is obtained. A simplified remote controllable grip hand is simulated by the curved beam bending model. We calculate the grip force of the hand to hold a body, controlled by light and heat. The simulation shows that the largest value of grip stress can be about 1Mpa. In order to optimize the light-induced bending, the effects on the effective moment of the parameters, such as the light intensity, the thickness of the beam and the decay distance of the material are further analyzed. It is found that the effective moment is not a monotonic function of these parameters. Therefore, proper light intensity, material and thickness must be chosen to get the largest bending.

The ionomer of sulfonated ethylene vinyl alcohol copolymers (EVOH) modified by poly (ethylene glycol) (PEG) (EVOH-g-SPEG) has been synthesized by the following process, EVOH was grafted by PEG through the Williamson reaction and sulfonic groups were introduced onto the end of PEG side chain by the open ring reaction of 1,3-propane sultone and the hydroxyl groups in EVOH. The crystalline structure and phase images of EVOH-g-SPEG membrane were characterized by X-ray diffraction (XRD) and atomic force microscope (AFM), and the ion conductivity is measured by a.c. impedance. XRD indicates that the water in EVOH-g-SPEG membrane region could destroy the membrane crystalline structure and the water absorption membranes are nearly amorphous. AFM phase images of the hydration membranes clearly show the hydrophilic domains, with sizes increasing from 10 to 35 nm as a function of the side chain length and the phase inversion could also be observed when n≥5 (n, numbers of grafting PEG side chain), which was consistent with a rapid increasing in water absorption. The a.c. impedance tests indicate that the comb-like EVOH-g-SPEG grafting with 2 PEG side chain provides the highest ionic conductivity (1.65×10^-3Scm^-1). Moreover, the tip displacement and the bending stress of ionic polymer-metal composites (IPMC) prepared by electroless deposition of argentum were gained by electro-deformation tests. Its results show that the tip bending stress increased with the increasing input voltage and reached to its maximum under the applied voltage of 3.6V~4.4V. IPMC based on the EVOH-g-SPEG membrane exhibits higher bending stress with its maximum value of 6.20MPa.

As fluid power sources, the micropumps are used in various applications such as biomedical engineering, micro electromechanical system and medical field etc. In this paper, a new type of valveless micropump driven by differential shape memory alloy (SMA) actuator is proposed. The valveless pump has inlet and outlet with tapered tube and does not need control of valves. The flow rectification of the valveless pump can be realized based on the nozzle/diffuser action. The differential SMA actuator controlled by alternative current makes the baffle of the valveless pump reciprocating motion. The operation principle, structure and control method of differential SMA actuator, the one-way flow mechanism and structure design of the valveless pump are analyzed. The experimental results indicate that the operation principle and design method of the valveless pump are feasible.

To realize active optics and further adaptive optics, high precision positioning technology with nanometer's resolution is believed to play a vitally important role in driving segmented mirrors of very large astronomical telescope (VLAT). The positioning actuators based on hydraulic technology, flexible-hinge principle and motor-reducer approach have been generally employed in VLAT to date. But such actuators prove to have the drawbacks such as hydraulic leakage, lagging, backlash and insufficient stroke, which could hardly be avoided in application of the above mentioned technologies. Naturally, these actuators can not satisfy the high-precise-positioning requirement for active and adaptive optics in VLAT. Aiming at upgrading the performance of actuators in VLAT, this paper presents the conceptual design of a small giant-magnetostrictive actuator which features stable nano-resolution positioning, large stroke, and instant response, high load capacity and free from backlash. Based on inchworm moving principle, the current research focuses on developing the elongating mechanism for longer step displacement with nanometric resolution and the clamping mechanism for large driving force. The feasibility of attaining a target actuator with 1000 microstrains and 4 nanometers resolution has been promised by relative experiments upon a Φ7×20 mm Terfenol-D rod in the authors' previous researches. Besides, the design of clamping mechanism as the other focus adopts magnetostrictive method to generate remarkable clamping force and to enable self-locking/pre-clamping behavior as well, which the other clamping methods are most unlikely to achieve. The current research is expected to contribute to meet the needs of high precision positioning for active and adaptive optics in VLAT.

Seismic pounding between the adjacent segments of the multi-span concrete highway bridges can result significant structural damage. The aim of this paper is to explore the possibility of implementing the semi-active control technology to mitigate the pounding of the highway bridges under severe earthquake excitations. The analysis of this study is focused on the highway bridges with base isolation systems. Mechanical model of the collision between the adjacent superstructure segments and the governing equation of motion of the highway bridges with pounding effect are firstly introduced, and the analytical model of highway bridges with a semi-active control system is presented by using the instantaneous optimal control algorithm for lighting the pounding of the structures. The results show that the semi-active control system can effectively reduce the structural pounding of the highway bridges under earthquake excitations if the semi-active control system was appropriately designed.

It is an obstacle issue for Carbon nanotubes (CNTs) applied in fiber reinforced polymer composites that CNTs is dispersed in nano-level, particularly for single-wall Carbon nanotubes (SWCNTs). In this paper, SWCNTs were treated by the coupling agent like volan and dispersing agent as BYK to improve the dispersion in the Glass Fiber/Epoxy composites. The result of dispersion of SWCNTs in composites was observed by Scanning electron microscopy (SEM). Then the Glass Transition Temperature (Tg) of these kinds of composites with treated and untreated SWCNTs were obtained by Dynamic Mechanical Thermal Analysis (DMTA). Moreover, the bending properties of these composites were tested.

We report studies of the electropolymerized polypyrrole (PPy) films around vertically aligned bamboo-like multiwall carbon nanotube (MWNT) arrays. Raman spectroscopy has revealed large percentage dipolarons resulting from highly conjugated PPy. The expected high conductivity of PPy-MWNT composite has also demonstrated by electrochemical studies. The SEM and TEM microscopy observations of the high mechanical strength, dense packing and strong adhesion exhibited in this composite are results of the π-stacking between the PPy backbone and the aromatic MWNT sidewalls.

Extrinsic Fabry-Perot interferometric strain sensors were assessed for their sensing capacity and survivability via the surface mounting and the interior embedment in the carbon/epoxy beams. Artificial delaminations of two different sizes were used to simulate delamination. The embedded EFPI-SSs along with surface-mounted SGs were used to evaluate the effect of the delaminations on bending stiffness induced by quasi-static loading on a comparative basis. The response of EFPI-SSs was shown to be linear up to a bending strain of 0.5% and was in good agreement with the interpolated strains of surface strain measurements. The embedded EFPI-SSs were able to differentiate the effect of the tensile delaminations on bending stiffness. The interior strain data from embedded EFPI-SSs were shown to be very useful to extrapolate the strain difference on both sides of the delaminations as well as deducing local stresses.

Space structures use fibre composite materials, due to their lightweight. This paper examines the impact response of symmetrical and hybrid composite laminates. Special attention is given to the stacking sequences used. The experimental study of structures has always provided a major contribution to our understanding. Even with the formidable growth in the use and capacity of computing power the need for experimental measurement is as compelling as ever. The design of hybrid composite structures is complicated by the number of design variables and the interaction of the constituents is the composite system. Since it is desirable to experimentally test the design and it is not practical to test a full scale model, the structural/material similitude concept is used to create a small scale model with a similar structural response. In the current study, experimental investigations were carried out to determine the response of four different combinations of hybrid laminates to low-velocity impact loading using an instrumented impact testing machine. Hybrid laminates were fabricated with twill weave carbon fabric and plain weave S2-glass fabric using vacuum assisted resin molding process with SC-15 epoxy resin system. Response of carbon/epoxy and glass/epoxy laminates was also investigated to compare with that of hybrid samples. Square laminates of size 100 mm and nominal thickness of 3 mm were subjected to low-velocity impact loading at four energy levels of 10, 20, 30 and 40 J. Results of the study indicate that there is considerable improvement in the load carrying capability of hybrid composites as compared to carbon/epoxy laminates with slight reduction in stiffness.

In this paper, the development and application of smart hybrid carbon fiber reinforced polymers (HCFRPs) are summarized. The active elements of the HCFRPs are carbon fibers/tows in terms of their piezoresistivity and electrical conductivity. Generally, the HCFRPs are divided into two types: HCFRP composites and HCFRP sensors. The HCFRP composites are fabricated with different types of continuous carbon sheets and function as both structural and sensing materials; while, the HCFRP sensors are fabricated with different types of continuous carbon tows and function only as sensing materials. It is shown that before the fracture of carbon fibers/tows the HCFRPs can be used as strain sensors in terms of the piezoresistivity of carbon fibers and after the gradual fractures of different types of carbon fibers they can be used as damage sensors to identify the damage condition of the HCFRPs and HCFRP-strengthened structures.

In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. It is important to assess fiber orientation, material properties and part defect in order to ensure product quality and structural integrity of CFRP because strength and stiffness of composites depend on fiber orientation. It is desirable to perform nondestructive evaluation which is very beneficial. An new method for nondestructively determining the fiber orientation in a composite laminate is presented. A one-sided pitch-catch setup was used in the detection and evaluation of flaws and material anomalies in the unidirectional CFRP composite laminates. Two Rayleigh wave transducers were joined head-to-head and used in the pitch-catch mode on the surface of the composites. The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite. Especially, ultrasonic waves were extensively characterized in the CFRP composite laminates both normal to fiber and along to fiber with using a one-sided direction of Rayleigh wave transducers. Also, one-sided ultrasonic measurement was made with using a Rayleigh wave transducers and a conventional scanner was used in an immersion tank for extracting fiber orientation information from the ultrasonic reflection in the unidirectional laminate. Therefore, it is thought that the proposed method is useful to evaluate integrity of CFRP laminates.

The I-V characteristic of the epoxy resin matrix composites containing conductive carbon black (CB) and sprayed CB is experimentally studied. The test results indicate that the I-V characteristic of the CB filled epoxy resin matrix composites is affected by the CB diameter. The composites containing sprayed CB with the diameter of 123nm have a linear relation between current and voltage and no variation in resistance post-exposed to an electric field. However, the composites containing conductive CB with the diameter of 33nm have a nonlinear I-V characteristic and the resistance of the composites post-exposed to an electric field decreases dramatically. A DC circuit model based on the experimental research is proposed. The occurrence of the electrical breakdown induces the nonlinear I-V characteristic and the dramatic decrease of the electrical resistance of the composites post-exposed to an electric field.

The thermoelectric cooler (TEC) has many potential applications in aerospace. Due to its lower coefficient of performance (COP), TEC consumes much more power than a mechanic cooler with the same cooling capacity does. To increase the COP of TEC and to improve its work reliability, we attached encapsulated phase change materials (PCMs) to the cold/hot sides of TEC directly, and several temperature control structures were formed. Temperatures at the cold/hot sides of TECs would be maintained within a designed range. The temperature control performances of these structures were experimentally investigated. The results show that the use of PCM at the hot side of TEC prolongs its operation time over twice than that without PCM. And the COP of TEC is increased more than 100%. The temperature at the cold side of TEC rises dramatically with the power failure, but if the encapsulated PCM is attached to the cold side, this phenomenon will not happen. It is demonstrated that the use of PCM could significantly improve TEC's temperature control performance and work reliability.

In order to substitute and recycle the existing automobile parts for GMT-Sheet, researches on the effects of GMT-Sheet on the establishment of precise joining strength, joining condition that are lap length of joining part, compression ratio, and closure speed must be carried out but until now, there is almost no case of systematic researches on joint of GMT-Sheet. Therefore, as there are many obstacles in joining of GMT-Sheet molding products or in production of stable molding products, the researches on these issues are required. Because of this, it is reality that GMT-Sheet is only applied to parts of newly developed automobiles instead of substituting the existing automobile parts. In this study, materials with each different fiber content ratio and fiber orientation state were used in the study for decision of molding condition of GMT-Sheet and the condition of lap joining. Clarify joining strength and lap joining efficiency during high temperature compression press lap joining molding of GMT-Sheet and research data regarding to the lap length of joining part was presented. Thus, the purpose of this study is to contribute to the substitution of existing products as well as usage development in non-automobile field and also to find out precise dynamic characteristics as designing data of structures.

SnO₂ nonopowders were prepared by sol-gel method and exposed to different thermal decomposition. The XRD and TEM analysis have been carried out. At higher temperature X-ray diffraction peaks are sharper with more intensified peaks. AlsoTEM micrograph reveals that the grain size of nanopowders changed from 10 nm to 80 nm regarding to different thermal treatment. The gas response shows characteristic dependence on dm (grain size). Responses to H2 and LPG gas as a function of operation temperature in dry air for the analyzed sensors with different nano powders show that smaller grain size are more sensitive to H2 and LPG gas.

Materials that can store low temperature latent heat are organic/inorganic chemicals, eutectic salt system and clathrate compound. Clathrate compound is the material that host compound in hydrogen bond forms cage and guest compound is included into it and combined. Crystallization of hydrate is generated at higher temperature than that of ice from pure water. And physical properties according to temperature are stable and congruent melting phenomenon is occurred without phase separation and it has relatively high latent heat. But clathrate compound still has supercooling problem occurred in the course of phase change and supercooling should be minimized because it affects efficiency of equipment very much. Therefore, various studies on additives to restrain this or heat storage methods are needed. Supercooling is the phenomenon that low temperature thermal storage material is not crystallized and existed as liquid for some time under phase change temperature. Because phase change into solid is delayed and it is existed as liquid due to this, heat transfer from low temperature thermal storage material is lowered. Therefore it is not crystallized at original phase change temperature and crystallized after cooled as much as supercooling degree and operation time of refrigerator is increased. In this study was investigated the cooling characteristics of the clathrate compound as a low temperature latent heat storage material. And additive was added to clathrate compound and its supercooling restrain effect was studied experimentally.

Since more than 10 years EADS Innovation Works, which is the corporate research centre of EADS (European Aeronautic Defence and Space Company), is investigating smart materials and adaptive structures for aircraft in cooperation with EADS business units. Focus of research efforts are adaptive systems for shape control, noise reduction and vibration control of both fixed and rotary wing aircraft as well as for lift optimisation of fixed wing aircraft. Two outstanding adaptive systems which have been pushed ahead in cooperation with Airbus Germany and Eurocopter Germany are adaptive servo flaps for helicopter rotor blades and innovative high lift devices for fixed wing aircraft which both were tested in flight for the first time representing world premieres. In this paper various examples of adaptive systems are presented which were developed and realized by EADS in recent years.

This paper describes the design and investigation of the SMP composite hinge and the morphing wing structure. The SMP composite hinge was based on SMP and carbon fiber fabric. The twisting recoverability of it was investigated by heating and then cooling repeatedly above and below the Tg. The twisting recoverability characterized by the twisting angle. Results show that the SMP composite hinge have good shape recoverability, Recovery time has a great influence on the twisting recoverability. The twisting recovery ratio became large with the increment of recovery time. The morphing wing can changes shape for different tasks. For the advantages of great recovery force and stable performances, we adopt SMP composite hinge as actuator to apply into the structure of the wing which can realize draw back wings to change sweep angle according to the speed and other requirements of military airplanes. Finally, a series of simulations and experiments are performed to investigate the deformations of morphing wings have been performed successfully. It can be seen that the sweep angle change became large with the increment of initial angle. The area reduction became large with the increment of initial angle, but after 75° the area reduction became smaller and smaller. The deformations of the triangle wing became large with the increment of temperature. The area and the sweep angle of wings can be controlled by adjusting the stimulate temperature and the initial twisting angle of shape memory polymer composite hinge.

Benefits in terms of aerodynamic efficiency, aeroelastic behaviour, stability and manoeuvrability performance coming from the adaptive variation of wing geometric (e.g. thickness and chamber) and mechanical (e.g. rigidity) parameters were widely proved. In this scenario, more and more efficient architectures based on innovative materials like shape memory alloys, piezoelectrics, magneto-rheologic fluids were ideated and related morphing ability was tested. Due to the large transmitted forces and deformations, for static applications, SMA based-on architectures were implemented. The essential idea of all these architectures is to integrate a SMA actuator, lacking of remarkable structural value, within a classical wing structure or within a suitably designed one. The main disadvantage of such architectures derives by the necessity of deforming a classical structure, not designed for reaching large displacements. In order to avoid these problems, in this work, the idea of integrating compliant structures by SMA elements, was considered. Some deformation strategies, focused on the wing aft part morphing, were ideated; related performance in terms of vertical displacement and rotation of the trailing edge was estimated by a FE approach. Each architecture is characterised by SMA rod elements able to guarantee large deformations and shape control under aerodynamic loads.

The term self-sensing composites is used to describe the case where the reinforcing glass fibres in advanced fibre reinforced composites are used as the sensors for chemical process monitoring (cure monitoring). This paper presents conclusive evidence to demonstrate that reinforcing E-glass fibres can be used for in-situ cure monitoring. The cure behaviour of an epoxy/amine resin system was compared using evanescent wave spectroscopy via the reinforcing E-glass fibre and conventional Fourier transform infrared spectroscopy. This paper also reports for the first time that evanescent wave spectroscopy via E-glass fibres can be used to detect the presence of silane coupling agents. Preliminary results indicated that the cure kinetics on the E-glass fibre surface, as observed using evanescent wave spectroscopy, were influenced by the silane coupling agent.

A novel structure of high voltage transducer's head is designed in this paper. Three pieces of quartz crystal is sandwiched between four metal electrodes. The converse piezoelectric effect of quartz crystal is used to sense the voltage applying on the transducer. In this paper, more attention is paid to selection of the crystal material, the shape of the electrode, the electrode material, the dimension of the electrode, and the distance of the electrode. After simulated with finite element method, the distribution of electric field at different condition is obtained. At last, an experiment is set up to validate the feasibility of applying intermodal interference in elliptical-core polarization maintenance fiber (E-core PMF) on high voltage transducer.

In this paper, an optical fiber biosensor based on multiple total internal reflections in heterodyne interferometry is proposed. The sensor is made of a long U-shaped multimode optical fiber which cladding is removed from the sensing portion of the fiber. With the optical fiber biosensor the phase shift difference due to the multiple total internal reflections (MTIR) effect between the P and S-polarizations is measured by using heterodyne interferometry with the optical fiber biosensor. Substituting the phase shift difference into Fresnel's equations, the refractive index for the tested medium can be calculated. The resolution of the sensor can reach 1.58×10^-6 refractive index unit (RIU). The optical fiber biosensor could be valuable for chemical, biological and biochemical sensing. It has some merits, such as, high resolution and stability, small size and real-time measurement.

A novel electrochemical DNA biosensor system based on methylene blue (MB) as hybridization indicator for DNA hybridization detection was presented in this paper. 5' end -SH modified DNA (HS-DNA) as nucleotide probes were self-assembled onto the surface of Au electrode. The complementary single stranded DNA (ssDNA) was hybridized with this nucleotide probes to form double-stranded DNA (dsDNA) system in Tris-HCl buffer solution (pH=8.0). Compared with the electrochemical signal of HS-DNA electrode, the electrochemical signal of dsDNA electrode system was decreased after the hybridization program. When the methylene blue, as hybridization indicator, was introduced into this system, the cathodic peak current (ΔIp) of Au electrode with dsDNA was increased significantly after the hybridization program. If the target was a mismatching base-pair DNA sequence, the electrochemical signal of electrode would have no changes almost. This result showed that this DNA biosensor system had an excellent sensitivity with a complete complementary DNA sequence. When the target DNA concentration was 5.0×10 ^-10 mol/L to 1.8×10^-9 mol/L, the cathodic peak current of Au electrode system with the MB as indicator was linearly related, and the detection limit was about 5.0×10^-10 mol/L.

Using ammonium per sulfate (APS) as initiator, PNIPAm was in situ polymerized in PVA aqueous so1ution and the transparent PNIPAm/PVA blending solution was obtained. PNIPAm/PVA fiber, showing polymer networks cross linked by the entanglement and hydrogen-bonding, was successfully prepared from the blending PNIPAm/PVA solution via wet spinning process with the saturated ammonium per sulfate aqueous solution as coagulation bath. In comparison with the PNIPAm/PVA blending solution, the single PNIPAm solution can not be prepared fibers. The best conditions for preparation of PNIPAm/PVA fiber such as PNIPAm mass ratio in the PNIPAm/PVA solution, PNIPAm polymerized time and reaction temperature in PVA aqueous so1ution was founded. The swelling performance and temperature-sensitive characters of the PNIPAm/PVA fiber were studied. The result showed that PNIPAm/PVA fibers maintain the temperature-sensitive characteristics associated with the roles of the component PNIPAm, the swelling rate of these fibers exhibited sharp change at about 32°C, and the temperature-sensitive property increased with the content of PNIPAm in the fiber increased.

The crystal structure, lattice constant, Curie temperatures, spin reorientation temperature, magnetization, magnetocrystalline anisotropy constant and magnetostriction of (Tb_0.36Dy_0.64)_1-xHo_xFe₂ (x=0.1, 0.2, 0.3) alloys were investigated. X-ray diffraction patterns demonstrate all the (Tb_0.36Dy_0.64)_1-xHo_xFe₂ alloys possess MgCu₂-type cubic Laves structure. The Curie temperature T_c of (Tb_0.36Dy_0.64)_1-xHo_xFe_1.95 alloys decreases slightly from 387°C for Tb_0.36Dy_0.64Fe₂ to 379°C for x=0.1, 375°C for x=0.2 and 362°C for x=0.3. The spin reorientation temperature T_r increases from -94.1°C for Tb_0.36Dy_0.64Fe₂ to -57°C for x=0.1 and -51°C for x=0.2. The magnetocrystalline anisotropy coefficient K₁ of (Tb_0.36Dy_0.64)_1-xHo_xFe₂ alloys decreases with increasing Ho concentration. The magnetostriction of (Tb_0.36Dy_0.64)_1-xHo_xFe_1.95 alloys was examined under applied magnetic field H (00.36Dy_0.64)_1-xHo_xFe₂ alloys (x≤0.2) have the character of giant magnetostrictive in a wide operating temperature range from -60°C to 80°C. The hysteresis of magnetostriction versus the applied field was reduced due to the addition of Ho concentration. Small amounts of Ho (x≤0.2) replacing Tb and Dy in the (Tb_0.36Dy_0.64)_1-xHo_xFe₂ formulation provide a much larger decrease in hysteresis losses with relatively small changes of magnetostriction in wide operating temperature range between -60°C and 80°C at magnetic field of 100mT.

The damping behaviors of Fe-13Cr-2.5Mo alloy at ambient temperatures and the AC magnetic field are tested with the improved reversal torsion machine. The precipitations distributing in the annealed alloy are also observed with SEM. The results show that because the defections decrease during the annealing treatment, causing a higher damping capacity of this alloy. This damping drops linearly to 63% when the ambient temperature changes from 23^oC to 500^oC, resulting from the gradual decrease of ferromagnetism. On the other hand, the AC magnetic field causes the damping capacity to drop sharply, and finally it reaches a much lower level.

Several composites, with outstanding magnetostrictive properties, have been synthesized combining a polyurethane base elastomer, with polycrystalline powders of Terfenol-D with a preferential orientation obtained by curing the material in a magnetic field. The morphology of the polymer matrix can be modified by changing the ratio of the hard /soft segment (F) of the polyurethane from 0.6 to 1.5. The influence of the morphology in the magnetostrictive response, for different composites, has been studied by following the storage modulus, E', in DMTA analysis. The magnetostrictive response has been studied as a function of Terfenol-D particle size and distribution (0-300, 212-300, 106-212, 0-38 μm), as well as a function of the content of the magnetostrictive particles in the composite. The highest response (about 1390 ppm) was obtained for a F=1.5 polyurethane and 50% wt of Terfenol-D of 212-300 μm particle size, oriented with a magnetic field of 0.5 T.

Based on the atomic model of rare earth-Fe₂ (RFe₂) compounds, the magnetoelastic model of Laves phase RFe₂ compounds has been proposed and it can be used to explain the strain caused by both a magnetic field and a compressive stress. The magnetic field dependence of Young's modulus under different bias stress has been founded according to magnetoelastic theory. It is found that the calculating result is in a good agreement with the experimental one for Tb_0.3Dy_0.7Fe₂ alloy. This result indicates that the founded model can describe the relation between Young's modulus and magnetic fields under different bias stress.

A system of distributed optical fiber sensor has presented based on the optical fiber sensor technology and detected the oil pipeline leakage using Mach-Zehnder optical interferometer. There are two interferential signals from sensor and reference light to put in computer has been analyzed using the analysis software LabVIEW of National Instruments' that can operate for the cross-correlation function, then compare the correlation peak to obtain the disturbance of oil leakage location, the detection precision 200m at around 50km for pipeline in the high speed sampling and data signal processing has obtained.

In the paper, we propose one new type sensor with using light modulation method. Having learned to delay a light signal by means of optical fibers, the temperature filed may be detected by this way. According to the light speed can be modulated in a photorefractive material in which written steady volume-index grating by two laser beams in opposite direction, so as to the light signal may transmit with phase modulating due to intervening of another frequency shifting laser beam. In the experiment, the inner grating would be written in an optical fiber in which the suitable Stannum has been doped. The periodic structure in the fiber can make the light signal reflect and the value of the phase shift is corresponding to the effective length of the periodic grating. According to magneto-optical Faraday effect, the temperature may changes polarization direction by shifting the Verdet constant. During the testing period, a Sn-doped fiber is exposed to measured temperature environment and certain uniform steady field. Under this environment, the more increasing of temperature, the shorter effective interference area is in the fiber. Comparing with the light delayed signal that transmits through fiber with different temperature, the delaying value may be corresponded to the temperature. This research work was supported by the National Natural Science Foundation of China under grant No.60472023.

A measurement of the leakage position using a distributed optical fiber acoustic sensor system based on Sagnac interferometer was demonstrated here. The effect of the input polarization on the output power of the demodulated signal was researched theoretically and experimentally. The influence of the polarization of the signal and the reference on the measurement sensitivity was calculated. It is shown that a higher coherence between them could obtain a higher measurement sensitive result; uprightness between them could not obtain any leakage signal. There are theoretical analyses and experimental simulation in this paper. When the system is 10.044km-long, the least frequency measured was 20 kHz and the calculated leakage position was 5-km, which was close to the real leakage position 5.022km. The relative difference was 0.44%.

Significant progress has been made in recent years on the design and fabrication of optical fibre-based sensor systems for applications in structural health monitoring. Two sensor designs have tended to dominate namely, fibre Bragg gratings and extrinsic fibre Fabry-Perot sensors. However, the cost and time associated with these sensors is relatively high and as a consequence, the current paper describes a simple procedure to fabricate intrinsic fibre Fabry-Perot interferometric strain sensors. The technique involves the use of hydrofluoric acid to etch a cavity in a cleaved optical fibre. Two such etched cavities were fusion spliced to create an intrinsic fibre Fabry-Perot cavity. The feasibility of using this device for strain monitoring was demonstrated. Excellent correlation was obtained between the optical and surface-mounted electrical resistance strain gauge.

Shape memory polymers (SMPs) have a number of advantages as compared with their metal counterpart, namely shape memory alloys (SMAs), in particular for some particular medical applications. The recent finding of the influence of moisture on the glass transition temperature of polyurethane SMPs, which are typically thermo-responsive in nature, enable us to realize not only the water driven feature for shape recovery, but also the recovery following a predetermined sequence, i.e., programmed recovery. Utilizing these new features, we demonstrate a few novel applications of this SMP, which might be of the particular interest for medical devices in, for instance, minimally invasive surgery.

Thermally activated shape memory polymers (SMPs) receive increasing attention in recent years. Different from those reported in the literature, in this paper we propose a new approach, i.e., using infrared light, for heating SMPs for shape recovery. We compare this approach with the traditional water bath method in terms of shape recovery speed in bending at both vacuum and no vacuum conditions. The results reveal that the shape recovery speed in infrared heating at vacuum condition is about eight times slower than that by hot water. However, the recovery time is more than doubled if without vacuum.

A series of polymers showing shape memory properties were developed based on polyalkenes derived from cyclooctene and related structures. These polymeric systems were synthesized via ring-opening metathesis polymerization (ROMP) using a well-defined ruthenium catalyst (Grubbs' type) by varying reaction conditions and proportions. Control over molecular weight was achieved by the inclusion of a chain transfer agent (CTA) and its influence on the behaviour of the obtained materials was evaluated. In order to provide them with shape memory behaviour the compounds were subjected to suitable chemical-thermal treatments and its characterization was accomplished by means of several techniques: differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), etc. Thus polymers developed herein could become a different alternative to the most studied and commercially available polyurethane based systems.

The fabrication and characterization, especially mechanical and electrical properties, of styrene-based shape memory polymer mixed with multi-walled carbon nanotubes (MWNTs) are presented in this paper. It is found that surface-modified MWNTs incorporated very well with resin processed by royal water, and dispersion was achieved by high-energy sonication in the solution. Scanning Electron Microscope (SEM) is shown that the particulate additives were dispersed homogeneously within matrix and served as local conductive paths. The glass transition temperature (Tg) of the composite containing MWNTs is lower than that of the pure SMP obtained from Differential Scanning Calorimetry (DSC). With the increasing filler content, resulting in the reduction of Tg increases. The composites have a better thermodynamic stability awarding to the results of Thermal Gravity Analyzer (TGA). The vibration of MWNTs in composite system was obtained from Raman spectrums. For the mechanical property of SMP composite with 8 wt% MWNTs, its Young's modulus increases by 12.1% and the tensile strength by 8.1% as compared with that of the pure SMP. Four-point Van De Pauw method is introduced to investigate the electrical property of composites. An electrical conductivity of 1.25×10^-3 S/cm is obtained for 8 wt% MWNTs composite.

In the past decades, there have been a number of research activities to control unwanted vibration of flexible robot arms. The electrorheological (ER) adaptive structures, which behave as viscoelastic damping structures with controllable shear modulus, are used to suppress the residual vibrations of the rotating flexible arm in this study. The flexible arm is designed as an ER sandwich structures, in which ER fluids is sandwiched between two elastic surface layers. Experimental tests are conducted. The vibration response performances of the beam subjected to different electric field intensity and motion conditions are demonstrated and evaluated. The experimental results obtained indicate that significant vibration attenuation is achieved at different operating conditions by applying an electric field to the rotating flexible arm.

Properties of a magnetorheological (MR) clutch have been investigated using newly developed MR fluids (suspensions) which consist of the carbonyl iron particles and thixotropic carrier fluid. The carrier fluid is composed of a rapeseed ester oil (vegetable oil) and synthetic smectite. The dependences of an output torque of the clutch on the applied magnetic field were examined under a fixed input torque for different densities of particles, surfactant or smectite in the MR fluids. The thixotropic behavior of the carrier fluids also was evaluated using a rheometer of the coaxial cylinder type. As for the MR fluid of 81wt% particles with 7wt% smectite, the output torque of the clutch increased with increases of the surfactant in the range of 0 to 5 wt%. On the other hand, the thixotropic effect was lost gradually with increase of the surfactant over 5wt% at the smectite concentration of 7wt%, but the output torque increased with increasing the surfactant accompanying by particles sedimentation. The sedimentation could be suppressed by the increase of the smectite concentration without decreasing of the output torque. As a result, the output torque reached to 57Nm by controlling the content of the surfactant and smectite in the MR fluids.

It was presented that adds a magnetorheological fluid squeeze film damper on the wheel spindle of ultrahigh speed grinder as a assistant elastic sustain, to attenuate the vibration of the wheel spindle and realize semi-active control to it. Work principle of magnetorheological fluid squeeze film damper was study and the simulation analysis of the wheel spindle motion was done. Base on the theory research the damper was designed and experiments was done. Experimental result show the vibration causing by the unbalance weight of wheel spindle can be attenuated effectively by adding a magnetorheological fluid squeeze film damper on it. At the same the finishing quality of workpieces can be improved 10%~20%, and the work efficiency of the machine can be raised 15%~25%. Research works provides a new method for wheel spindle design of the ultrahigh speed grinder.

Cosmic radiation shielding properties are important for spacecraft. Hydrogenous materials such as polyethylene have been shown effective against galactic cosmic rays (GCR) and solar energetic particles. Ultrahigh molecular weight polyethylene (UHMWPE) fibers have advanced mechanical and physical properties, which are very valuable for NASA missions. Unfortunately, poor interface in the UHMWPE fiber/polymer matrix hinders the structural integrity of the composites, and restricts the effectiveness of radiation shielding for practical applications. Fiber treatment methods can not only incur an extra cost for manufacturing the composite structures, but also may sacrifice intrinsic properties of the fibers. In our study, we fabricated a reactive nano-epoxy matrix with reactive graphitic nanofibers, which showed enhanced mechanical (including strength, modulus and toughness) and thermal properties (higher T_g, stable CTE, and higher ageing resistant), as well as wetting and adhesion ability to UHMWPE fibers. 1 GeV/nucleon ³⁵Cl ions, high energy ions for the complex GCR heavy ion radiation field, was used for the radiation tests. The results showed that the radiation shielding property was not reduced by the addition of graphitic nanofibers. The studies indicated that the UHMWPE fiber/nano-epoxy will have potential in manufacturing more durable space composites and structures.

Titania nanotube array with an average tube diameter of 110 nm and length of 700 nm was fabricated by a potentiostatic anodization on titanium metal sheet. Nickel oxide was then loaded into titania nanotubes by electrodepositon-electrooxidation and heating treatment processes. The morphology and microstructure of the nanocomposite were investigated by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and energy dispersive x-ray (EDX) analysis. Nickel oxide could well coat on titania nanotubes from inner wall to pore mouth with a high loading amount up to 36.4% of nickel-to-titanium atom ratio. Such a well-defined nickel oxide-titania/titanium nanotubular composite was designed as a functional electrode for an electrochemical capacitance application. The result of electrochemical characterization exhibits a highly reversible redox peaks by cyclic voltammetry in sodium hydroxide aqueous solution. High specific supercapacitance was accordingly achieved up to 7.8 mF cm^-2 due to the intensive loading of nickel oxide.

Electroactive response of suspensions of mesoporous silica and its nanocomposites with conducting polyaniline and copolyaniline inside its channels were examined under an applied electric field, mainly focusing on their rheological characteristics. Initially these conducting polymer/mesoporous silica nanocomposites were synthesized and their physical properties were studied by scanning electron microscopy, transmission electron microscopy and N₂-adsorption isotherm. Both mesoporous silica and its nanocomposites were then adopted as an electrorheological (ER) material, being dispersed in silicone oil. Typical ER behaviors of shear stress curve as a function of both applied electric field and shear rate were observed for these ER systems. In the absence of an electric field, the suspensions behaved almost like Newtonian fluids. However, when an electric field was applied to the suspension, their shear stresses increased with a shear rate, demonstrating a yield stress. Comparing with ER fluids based on mesoporous silica and polyaniline, the polyaniline/mesoporous silica based ER fluid showed enhanced ER performance due to the anisotropic characteristics of electrical properties of the polyaniline/mesoporous silica particles. In addition, it was found that the shear stress model (Cho-Choi-Jhon model) gave a good representation of the flow curves of these nanocomposite systems.

Mechanical behaviors of the nanoindentation into the films of the polystyrene (PS) and the polyhedral oligomeric silsesquioxane (POSS) reinforced PS (propyl-POSS-PS, P-POSS-PS) were studied using the molecular mechanics simulations. The serrated load-displacement curves of two kinds of polymers were obtained. And the curves show that the loads increase with increasing displacements. A method to compute the hardness of homopolymers in the molecular simulations of the nanoindentation was proposed by considering the response of the load-indentation depth and the constructional deformations of the simulation models. The results indicate that the hardness of the P-POSS-PS (9.1mol% propyl-POSS attached) is about 60% higher than that of the PS. The hardness of polymers can be observably improved by the POSS. A formula is deduced to characterize the relationship between the hardness and the indentation depth of common polymeric materials based on a kind of representative polymer nylon. Computational results prove that this formula is valid to a large proportional of polymers. Afterward the hardness of the PS and the P-POSS-PS were corrected and the necessary indentation depths for the credible hardness were provided.

Piezoelectric ceramic/polymer composites have been widely studied because of their theoretical interest and technological applications. The 1-3 piezoelectric composites have recently received increased attention due to their potential applications in underwater acoustics and biomedical imaging. 1-3 piezoelectric composites have piezoceramic fibers, embedded in an elastically soft polymer matrix which is either piezopassive or piezoactive. Their electromechanical properties of the piezoelectric composites can be tailored to meet specific applications and their flexibility offers an additional advantage over the brittle monolithic piezoelectric. In this paper, we study the effects of the variation of the polarization orientation of the piezoelectric materials on the effective properties of 1-3 piezoelectric composites by using the micromechanics-based Mori-Tanaka method. Results for PZT/P(VDF-TrFE) composite show that the effective electromechanical properties are not significantly affected by the polarization orientation. However, the performance of the composite is significantly affected at low volume fraction of the piezoceramic fiber. These results can provide useful information for optimizing the design of 1-3 piezoelectric composites for specific applications.

The impact drive mechanism utilizes friction and impulsive force caused by rapid deformations of a piezoelectric element to generate movement. Most of the devices reported in the past are linear mechanisms. In this paper, a rotary mechanism is developed and its motion characteristic is investigated systemically. The rotational movement is estimated theoretically. In experiments, the relationships between the rotational velocity and frequency, amplitude, rise time of the driving voltage are measured. Besides, as an important factor to influence the piezo actuator's performance, the fatigue of the mechanism is discussed originally.

Ultrasonic motor (USM) as a new type of driving motor has many good features compared with conventional electromagnetic motor. However, due the content of Pb in the driving element piezoelectric ceramics, Pb(Zr_x,Ti_1-x)O₃ (PZT), the application of USM will be restricted from the viewpoint of environmental requirement. In this paper lead free piezoceramics, Mn doped 0.94(Bi_0.5Na_0.5)TiO₃ -0.06BaTiO₃(BNT-BT), was used as driving element in ultrasonic motor in replacing PZT. Though the piezoelectric property of BNT-BT ceramic is inferior to that of PZT, the USM with BNT-BT driving element shows promising result and potential to replace PZT ceramic in application of ultrasonic motor.

The piezoelectric response of pure Nylon 11 and conducting Polyaniline (PANI) filled Nylon 11 is presented. Nylon 11 samples were filled with PANI fillers of two different concentrations (1% and 5% w/w) each. The samples were poled using Corona discharge technique with poling field of 200 kV/cm and 350 kV/cm. The piezoelectric strain constant d₃₁, stress constant e₃₁ and electromechanical coupling coefficient k₃₁ of pure and PANI filled samples were measured up to 100°C. The study suggests that the piezoelectric coefficient (d₃₁) of the PANI filled Nylon 11 shows considerable decline with respect to its individual component. The thermal stability of the PANI filled samples improved and is almost stable at comparatively low temperature than pure Nylon 11.

In this article, a novel approach for demodulation of fiber grating sensors with high resolution is proposed based on a hybrid fiber optical bistablity device (OBD). This OBD is consisted of a FFP ring-cavity laser, fiber Bragg grating (FBG) and a certain optoelectronic feedback circuit. The optical bistability can be realized through alternative the center wavelength of the tunable fiber laser when the output power of the laser is fixed. The Bragg wavelength of sensing grating is determined by the switching on voltage of OBD.

In this article, a novel technique of fiber sensor demodulation for fiber Michelson interferometric sensor is proposed. The output optical signal of the interferometric sensor is processed by a hybrid optical bistable device in frequency domain. When the optical path difference between the two arms of the sensor changing, it will cause the bistable device switching on and switching off. The measurement is realized by counting the optoelectronic pulses. The experimental and simulation results show that this technique with high accuracy, the resolution of the length measurement is nanometer level.

A FBG-based dynamic strain sensor system, whose responding frequency and resolution can be high as 16Hz and ~1με respectively, is described and the system is applied to monitor the dynamic strain of Como Railway Bridge in Australia. The results of one-month long measurement show that the system can figure out all dynamic strain caused by passed trains and also prove the stability of the sensor system.

Dynamic effects are very important in improving the design and study of the micro-robot. In the paper, our preliminary work in using ICPF to develop a novel tortoise-like flexible micro-robot with four legs and one tail is reported, which can crawl and swim underwater. ICPF is the abbreviation of Ionic Conducting Polymer gel Film which is a kind of smart film and can give large and fast bending displacement in the presence of a low applied voltage in wet condition. For controlling and analyzing easily the robot, we establish the micro-robot's tail dynamic model by applying Pseudo-Rigid-Body-Dynamic-Model (PRBDM). The model is established by considering the dynamic effect of the robot's tail, which is based on statics and kinematics. Then, the frequency analysis of a micro-robot based on PRBDM is investigated. Based on the PRBDM, the relation between the robot's tail angle displacement and the electrical voltage's frequency ω is theoretically derived and the simulation result for the tail's angle displacement is performed.

This paper presents a new way of using a theory of topology optimum and PID control theory to design a microgripper system. The driver of microgripper is a piezoelectricity ceramics (PZT) microactuator. This study uses a PZT microactuator of 5 mm length, 3 mm width and 0.5 mm thickness and analyzes the different performances of the microactuator when applied to different voltages. The study defines the compliant amplifier design domain as 9.2 mm × 8.1 mm with a 0.5 mm thickness and discusses the effect of different optimization parameters. The driver is a PZT microactuator that can actuate 10.46μm output displacement to the compliant microgripper. A PID controller was designed for the microgripper system. Improvement of the control performance of the system was obtained.

An excavator attached to a rotary working device is used principally in industrial work. In particular, they are used in the building industry and public works. This research concerns the rotary automatic control of an excavator attached to a rotary working device. The drilling excavator is used in the crushed stone industry and the dragline excavation system is employed in the construction industry. Cases of the excavator's use in agriculture have been the subject of a relatively few studies. However, several modified excavator designs have been released in recent years. Applied excavator products are primarily utilized under relatively severe environmental conditions. In this study, we focus on the uses of an excavator in agricultural work. The readjustment of arable land and the reduction of weeds in agricultural applications both require skilled hand-operation of the machines. As such workers have been shown to develop problems with regard to working posture and proper positioning while laboring, a more appropriate excavator design may prove useful in such applications. Therefore, this pilot study is focused primarily on the rotary automatic control of an excavator attached to a rotary working device, and will adapt smart materials to the excavator applications for developing redesigned excavator having a light weight. The excavator is attached to a rotary working device on a normal excavator's platform, and the position and orientation of the mechanism between the joints and the rotary working device was determined. Simulations were also conducted of the excavator attached to the rotary working device. With an eye toward the use of this mechanism in agricultural work, we also conducted a set of kinematic analyses. The rotary working device was assumed to have 3 DOF, and was comprised of 5 links. Computer simulations were also conducted using the developed excavator model. In order to adequately evaluate the possible performance of such a system, kinetic analysis, simulation with a soil model, FEM analysis with structural strength analysis, and changes to the smart materials with high rigidity will be required in the future. In addition, experiment and analysis of a prototype, durability experiments, and analyses utilizing S-N curves will be necessary, as well further research into the overall reliability of such a product.

Recent advances of microelectromechanical system (MEMS) technology have opened new opportunities for amorphous silicon (α-Si) microbolometer focal plane arrays (FPAs) both for military and civil applications. α-Si membrane is chosen for sensitive material of microbolometer FPAs due to its high temperature coefficient of resistance (TCR), high resistivity and good mechanical properties. However, α-Si membrane also has the disadvantage of high 1/f noise, strict preparation conditions and metastable effect. So nowadays, researches are focused on properties of α-Si membrane to gain high performance of microbolometer FPAs. Since the pulsed bias readout mode of microbolometer FPAs causes a non-steady-state of α-Si membrane during the operation, the transient thermal-electrical response process of the sensing pixel is analyzed detailedly in this paper to predict the thermal and electrical performance of α-Si microbolemeter FPAs such as responsivity, noise equivalent temperature difference (NETD), detectivity and power dissipation. Numerical simulations are presented to investigate the factor which affects the performance of α-Si microbolometer FPAs. The imaging experiment results obtained from a 320×240 α-Si microbolemeter FPA are in good agreement with the theoretical analysis. The way to improve the performance of α-Si microbolemeter FPAs is given in the end of this paper.

Barium zirconate titanate BaZr_xTi_1-xO₃ (BZT, x=0.25-0.55) ceramics have been prepared by traditional mixed oxide process. Dielectric and Raman scattering experiments were performed on various compositions. The evolution of Raman normal modes with increasing x suggested that BZT exhibits a variation of properties from conventional ferroelectric to relaxor with increasing Zr concentration. The DC electric field tunable behavior of the environmental friendly lead-free perovskite BZT relaxor ceramics was studied in the temperature range from 77 to 350 K. The results have been analyzed in relation to tunability and K factor (figure of merit) of the tunable dielectric materials.

Polyethylene glycol (PEG)-assisted solid state reaction route is employed to prepare the relaxor-type ferroelectric powders and ceramics of (1-x)Pb(Ni_1/3Nb_2/3)O₃−xPbTiO₃ (PNN-PT) with the morphotropic phase boundary (MPB) composition at x=0.36 (0.64PNN-0.36PT). PEG additive with the molecular weight of 200 is introduced into PNN-PT oxide precursors in order to obtain the perovskite phase. The XRD and TG/DSC results demonstrate that the interactions between PbO and PEG favor the transformation from the lead-rich pyrochlore to the lead-deficient pyrochlore, thus facilitating the formation of the perovskite. Consequently, nearly pure perovskite 0.64PNN-0.36PT powders are synthesized at a relatively low temperature of 850 °C. A significant improvement of electric properties of the ceramics sintered at 1200 °C is achieved by PEG modification. The dielectric constant at room temperature and the maximum dielectric constant at T_c reach 4987 and 24307, respectively, at a frequency of 1 kHz. The piezoelectric constant d₃₃ is 460 pC/N.

A new trial of standing wave type bi-directional moving linear ultrasonic motor has been studied in this paper. Finite element modeling analysis revealed that by connecting three rectangular metal plates in different lengths together by two weak links, two bending vibration mode standing waves, i.e., one in sine wave and the other one in cosine wave, with nearly the same wavelength can be formed in the middle plate. With four pieces of PZT-4 piezoceramics mounted to the middle plates as driving elements, a new type of bi-directional linear moving ultrasonic motor of 60mm in length and 10mm in width has been designed, fabricated and characterized. The following performances have been achieved: maximum velocity 220mm/s, maximum output force 180gf, and resolution better than 0.2μm.

In industrial applications, shape memory alloys (SMAs) are very often used as two-way actuators, in the form of coil springs, which capitalize on the capacity of small shear to produce large displacement. One way to achieve the two-way actuators is using a one-way shape memory effect SMAs spring with a bias spring, the other way is two-way shape memory effect (TWSME) SMAs spring. However, the TWSME is not inherent property of SMAs, suitable thermomechanical training is required to develop this effect. In this work, methods of developing TWSME are designed for SMAs and factors which affect the TWSME are investigated. Two types of TWSME spring are obtained using the designed methods. One type is extension spring, which can extend upon heating and contract upon cooling and this other type is contraction spring, which can contract upon heating and extend upon cooling. The actuation behaviors of these two types TWSME are investigated. And the stability of TWSME was also studied with working cycles and annealing.

There are a wide range of potential applications of magnetically shape memory alloy (MSMA) actuators in high force positing systems. This paper makes an investigation in the structure and control strategy of MSMA actuators based on the experimental study on the control properties of MSMA material. The structure, operation principle and control strategy of three kinds of linear MSMA actuators are discussed. They are the basic linear MSMA actuator, the differential linear MSMA actuator and the inchworm type linear MSMA motor. Besides, a new type of rotating MSMA actuator is introduced. The feasibilities of all the introduced MSMA actuators have been proved by the prototype machines.

This paper presents a frequency response analysis of nickel-titanium Shape Memory Alloy (SMA) wires that are the active elements in an SMA actuator. Frequency response analysis is the measurement of the relative magnitude and phase of an output signal, with respect to an input signal, at spot frequencies covering a frequency range of interest. In this case, the input signal is the electrical heating power applied to the SMA wire, the output is the tensile force on the wire, and the frequency range is 0.1 Hz to 100 Hz. The purpose of such measurements is to obtain a transfer function, relating power input to force output, that can be used to design a feedback control system for a precision SMA force actuator. Measurements are presented for wires having diameters of 75, 100 and 125 μm, in ambient air at room temperature, under various combinations of stress and strain. It is shown that the phase response is independent of stress and strain, while the magnitude response varies by about 7 dB.

Transformation behavior, shape memory characteristics and superelasticity of Ti-(40-x)Ni-10Cu(at%)(x=0~2) alloy ribbons were investigated. All ribbons showed the two-stage B2-B19-B19' transformation behavior. The temperature gap between Ms'(the B2-B19 transformation start temperature) and Ms(the B19-B19' transformation start temperature) was large(~ 40 K), which was ascribed to internal stress fields around dislocations introduced by melt spinning. Ti₂Ni particles were observed in Ti-39Ni-10Cu and Ti-38Ni-10Cu alloy ribbons, while they were not found in a Ti-40Ni-10Cu alloy ribbon. Volume fraction of Ti₂Ni particles increased from 3 % to 12 % with increasing Ti-content from 51 at% to 52 at%. Both Ms and Ms' decreased with increasing Ti-content, which was ascribed to formations of Ti₂Ni particles resulting in a decrease in Ti-content of matrix. Ti-(40-x)Ni-10Cu alloy ribbons showed perfect shape memory effect and superelasticity. The transformation hysteresis associated with the B2-B19 transformation was 6-10 K depending on Ti-content.

TiNi shape memory alloys exhibit excellent damping capacity in martensite state or during the martensitic transformation. However, the alloys in these situations are very soft (as low as 100 MPa) due to the reorientation of martensite variants or detwinning in the deformation process. In the present paper, we report NiTiNb shape memory alloys with high yield strength (287 MPa) and high damping capacity (Q^-1 greater than 10^-2). The NiTiNb alloys are characterized by a composite feature in microstructure, i.e. isolated martensitic NiTi(Nb) islands were randomly distributed in the eutectics of B2-TiNi(Nb) and β-Nb. The isolated NiTi(Nb) phase provides excellent damping capacity and the eutectics contribute to high yield strength. The influence of Nb addition on the microstructure, phase transformation temperature, damping capacity and the mechanical properties of the TiNiNb alloys were reported.

In this study, formaldehyde, one of the major volatile organic compounds, is degraded using nano TiO₂ photocatalysis for improving indoor air quality. Polytetrafluoroethylene filter, a low cost and commonly used material in industry, is successfully employed as the substrate for nano TiO₂ photocatalyst coating at room temperature. A specific experimental set-up that is similar to actual air purification system is developed for the testing. The effects on formaldehyde photocatalytic degradation rate of some key factors are investigated. These factors include initial concentration, stream flow rate, reaction temperature, light source intensity, and relative humidity. Within the experimental ranges, the degradation rate increases with the enhancement of initial concentration and light intensity. The stream flow rate and reaction temperature have dual effects on the degradation rate. The degradation rate is relatively high under low relative humidity.

Compared with ordinary polysilicon films and monocrystalline silicon, heavy doped polysilicon nanofilms have better piezoresistive properties and better temperature characteristics. Therefore, pressure sensors made of polysilicon nanofilms will have many corresponding advantages, including high sensitivity and complete self-compensation of temperature coefficients. In this paper, the influence of doping concentration on temperature coefficient of resistance (TCR) and temperature coefficient of gauge factor (TCGF) is deeply studied to optimize doping concentration in order to make temperature coefficients lowest. TCR and TCGF of samples with doping concentration of 4.1×10¹⁹cm^-3, 1.0×10²⁰cm^-3, 2.0×10²⁰cm^-3, 4.1×10²⁰cm^-3, 7.1×10²⁰cm^-3 are tested at temperature range 23°C to 270°C, respectively, and the microstructures of the samples are also observed by the method of scanning electron microscopy (SEM) and transmission electron microscope (TEM). The experimental results have been explained reasonably based on the tunneling piezoresistive theory proposed before. Based on both experimental results and theoretical analyses, to obtain a zero value of TCR and a low value -0.1%/°C of TCGF, the optimal doping concentration of the films of 80nm thickness should be about 3×10²⁰cm^-3.

Ga₂O₃-core/ZnO-shell coaxial nanocables were fabricated via a two-step process. While Ga₂O₃ core nanowires were synthesized by thermal heating of GaN powders, ZnO shell layers were deposited on the core nanowires by using the atomic layer deposition method. The samples were characterized by using scanning electron microscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and photoluminescence spectroscopy (PL). XRD, lattice-resolved TEM, and selected area electron diffraction revealed that the coated shell layers comprised a hexagonal ZnO phase. EDX analyses were in good agreement with what can be expected for the ZnO-coated Ga₂O₃ nanowires. The shape of PL spectrum has been changed by the coating process, suggesting a contribution from ZnO shell layers.

Fiber optic sensors have become increasingly attractive for application in advanced intelligent coal mines, which consist of extensive sensor network to monitor the structural integrity, environmental safety and production parameters. Fiber optic based strain (mining pressure), temperature, water pressure, methane gas, seismic and ultrasound sensors can be used to monitor the condition of the coal mine and provide information for accident prediction and early warning. We report for the first time an all fiber optic comprehensive coal mine safety monitoring system. The system is capable of methane gas monitoring, temperature monitoring, seismic event and mine pressure detection and water pressure monitoring. The advantages of this fiber optic sensor system include intrinsic safety in explosive environment and multiparameter monitoring. The technology potentially can be used to replace many discrete and incompatible monitoring systems currently deployed in the coal mines and consequently greatly enhance coal mine safety.

A double-coating optical fiber sensor which is used for soil deformation measurement is proposed in the paper. It could be used in non-destructive detection of large scale structures, health evaluation of the civil structures and forecast of geologic hazard such as landslide. The structure of the double-coating soil mechanical sensor is designed and the mechanical model of the mutual effects between the optical fiber and the soil is founded. Under the static press, the deformations of the soil dam model and the slope model are experimentally detected by using the calibrated white-light fiber soil mechanical sensor. In the experiment, a 500 millimeter length double-coating soil mechanical sensor is chose to detect the soil deformation. Measuring results indicate that the mechanical transfer coefficient is 0.31 and the measuring range of deformation is from zero to 10 millimeter. Compared with the outside stickup sensors, the embedded soil mechanical optical fiber sensor can faithfully represent the deformation inside the soil model, the measuring result is closer to the real soil deformation and the measuring method is more effective.

An application of D-type optical fiber sensor (OFS) in the temperature measurement is proposed. The sensor based on attenuated total reflection (ATR) effect could be like as a probe to sense a liquid or gas temperature in real-time. We use the optical spectrum method combining with the minimum value of relative power ratio technique to analyze and record the temperature. The temperature resolution is in the region of 0.01°C for the measuring range of 24~75°C. It has some merits, such as, simple, sensitive, and remote test.

Cure monitoring is a term that is used to describe the cross-linking reactions in a thermosetting resin system. Advanced fiber reinforced composites are being used increasingly in a number of industrial sectors including aerospace, marine, sport, automotive and civil engineering. There is a general realization that the processing conditions that are used to manufacture the composites can have a major influence on its hot-wet mechanical properties. This paper is concerned with the design and demonstration of a number of sensor designs for in-situ cure monitoring of a model thermosetting resin system. Simple fixtures were constructed to enable a pair of cleaved optical fibers with a defined gap between the end-faces to be held in position. The resin system was introduced into this gap and the cure kinetics were followed by transmission infrared spectroscopy. A semi-empirical model was used to describe the cure process using the data obtained at different cure temperatures. The same sensor system was used to detect the ingress of moisture in the cured resin system.

It is a novel study field for automatic healing composite by using microcapsules. A series of microcapsules are prepared by in-situ polymerization technology with poly (urea-formaldehyde) (PUF) as a shell material and dicyclopentadiene (DCPD) as core materials. The effects of surfactant on the physical properties of poly (urea-formaldehyde) microcapsules were researched by using Styrene/maleic anhydride copolymer (SMA), Polyvinyl alcohol (PVA) and sodium dodecylbenzene sulfonate (DBS) solutions of different concentration. The properties of microcapsules, including the surface morphology, chemical structure, and thermal properties of microcapsules are characterized by using Optics microscope (OM), Fourier transfer infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and Thermal gravity analysis (TGA). The content of core material was calculated. The results indicated that PUF microcapsules can be synthesized successfully. The DBS was favorable to microcapsulation and the microcapsules had smooth outer surface when the concentration of DBS was close to critical micelle concentration (CMC). The PUF microcapsules filled with DCPD had the content of DCPD was 85% and exhibit a good chemical stability below 218°C.

The component of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coating(TBC); the failure of such coating can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimizing the inspection intervals and in finding the appropriate remedial actions. In this paper the potential of NDT techniques applicable to the metallo/ceramic coating hot parts are discussed in the light of both results obtained on laboratory aged specimens and in field measurements on operated components. An investigation of the NDTs capability to detect damage evolution was performed on thermal-cycled specimens coated with TBC by pulsed thermography. The observation of metallogaphy sections of the thermal cycled specimens allowed to give the right the interpretation to the results of NDT methodology and enlightened its specific characteristics and potentiality. Moreover in field applicability is discussed for each technique. Finally it is shown how an integrated approach of suitable coating evolution models and complimentary NDT techniques can provide an interesting assessment of the damage level of the metallo/ceramic coating of operated rotating blade

The longitudinal, shear and surface waves have been used to an Ultrasonic wave exploration method to identify internal defects but it has technical difficulties to detect defects in a limited space with having several millimeters board thickness. It is applicable to use Lamb wave, a kind of induction ultrasonic wave that has a relatively high inspection efficiency and defect detection sensitiveness compare to perpendicular or square explorations in terms of the internal defect detection in these kinds of thin board. The Lamb wave is a special type of induction ultrasonic wave to propagate to a board and it is effective to inspect such as board structure, cell structure, etc. Recently a laser is being used to generate Lamb wave but it not being widely utilized because of difficulties in receiving and selective generation in various modes Lamb wave generating and a low S/N ratio, wide range of generating frequency band when a laser is used. This paper aims to study that the defect exploration method to specimen's thickness, using an characteristic of an ultrasonic wave generating in ablation area and thermoelasticity area, has been applied to using a way of receiving it by Air-Coupled Transducer and transmitting it by an ultrasonic wave and a way of non-contact receiving and transmitting ultrasonic wave using a laser. The longitudinal, shear waves have been used in 60mm thickness specimen and Lamb wave in 3mm to run artificial defect detection test. In this way, the usefulness of non-contact laser ultrasonic wave has been verified. To confirm the possibility of implementation on natural defect existing at real welding part, thickness in 3mm SM45C and STS304 artificial defect specimen has been made and defect detection test using Lamb wave has been executed. Detected signal by signal treatment has been expressed in visual not RF signal. By doing so the convenience of defect detection has been attempted and the effectiveness of defect signal visualization using Lamb wave has been confirmed compare with defect image through SAT.

In this work, a carbon/carbon (C/C) composite material was nondestructively characterized with non-contact ultrasonic methods using automated acquisition scanner as well as contact ultrasonic measurement because (C/C) composite materials have obvious high price over conventional materials. Because of permeation of coupling medium such as water, it is desirable to perform contact-less nondestructive evaluation to assess material properties and part homogeneity. Also through transmission mode was performed because of the main limitation for air-coupled transducers, which is the acoustic impedance mismatch between most materials and air. Especially ultrasonic images and velocities for C/C composite disk brake was measured and found to be consistent to some degree with the non-contact and contact ultrasonic measurement methods. Low frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. Measured results were compared with those obtained by the motorized system with using dry-coupling ultrasonics and through transmission method in immersion. Finally, results using a proposed peak-delay measurement method well corresponded to ultrasonic velocities of the pulse overlap method.

Damping capacity is another primary characteristic of shape memory alloys (SMA) besides shape memory effect and superelasticity. Damping behavior of Ti-riched TiNi SMA, porous TiNi SMA and a novel TiNi/AlSi composite have been investigated using dynamic mechanical analyzer (DMA) in this investigation. All these alloys are in martensitic state at room temperature and thus possess the high potential application value. Ti_50.2Ni_49.8 SMA has better damping capacity in pure martensitic state and phase transformation region due to the motion of martensite twin interface. As a kind of promising material for effective dampers and shock absorbing devices, porous TiNi SMA can exhibit higher damping capacity than the dense one due to the existence of the three-dimensioned connecting pore structure. It is found that the internal friction of porous TiNi SMA mainly originates from microplastic deformation and mobility of martensite interface and increases with the increase of the porosity. A novel TiNi/AlSi composite has been developed successfully by infiltrating AlSi alloy into the open pores of porous TiNi alloy with 60% porosity through compression casting. It shows the same phase transformation characteristics as the porous TiNi alloy. The damping capacity of the composite has been increased and the compressive strength has been also promoted remarkably. Suggestions for developing higher damping alloys based on TiNi shape memory alloy are proposed in this paper.

Relationship between amount of recoverable strain and pre-strain in Fe-25%Mn-4.5%Si-1%Cr-2%Ni shape memory alloy (SMA) was measured in tensile tests. The results show that recoverable strain increases with increasing pre-strain lower than 5%, and decreases rapidly when the pre-strain go beyond 5%. By X-ray diffraction, the effect of pre-strain on volume fraction of stress induced ε martensite (εM) was determined and it was found that amount of εM first keeps increasing with pre-strain and then reaches saturation when pre-strain is over 8%. Transmission electron microscope (TEM) observation shows that morphology of stress induced εM for different pre-strain differs greatly and thus has different influence on shape memory effect (SME) of the alloy. Three types of morphology of εM were observed for different pre-strain, which are thin εM plates, wide εM bands of multilayer and intersecting εM variants respectively.

The environment of orthopaedic implants sometimes induces vibrations at the contact of the modular prostheses components. In this paper the fretting behavior of NiTi SMAs against human bones in the imitated human physiological solution was studied at various displacement amplitudes and Ph value. Surface micrograph after fretting was observed by MEF3 microscope. Appearance of fretting scar was measured by 2206 roughness tester. The result shows that the friction coefficient between the bone and NiTi SMAs pairs declined due to the lubrication effect of Hank's solution, and which increased when Ph value of fluid was not 7.2 due to the corrosion. So the friction coefficient at acid and alkali Hank's solution is higher than those at the neutral solution and ambient air condition. Generally speaking, the friction coefficient between the bone and NiTi SMAs tend to be stable with the increasing amplitude at all test conditions. It is because that the surface was oxidized to restrain the forming of wear debris and the further development of fretting scars. Although the length and width of the wear scars in simulation body fluid are smaller than that at ambient air condition, the surface of NiTi SMAs damaged is characterized by deep scratches with debris particles within the contact area. Fretting regime of NiTi/bones pairs exhibits the mixed regime at ambient air condition and the slip regime in the Hank's solution.

Transformation behavior, shape memory characteristrics and superelasticity of Ti-(45-x)Ni-5Cu-xV(at%)(x=0.5-2.0) alloys were investigated. The B2-B19-B19' transformation occurs when V content was more than 1.0 at%, while the B2-B19' transformation occurred when V content was 0.5 at% in solution treated specimens. However, the B2-B19 and B19-B19' transformations were not separated clearly in the thermo-mechanically treated specimens. A temperature gap between Ms'(the B2-B19 transformation start temperature) and Ms(the B19-B19' transformation start temperature) increased from 8 K to 22 K with increasing V content from 1.0at % to 2.0 at% in solution treated specimens. One-stage elongation associated with the B2-B19' transformation occurred in a Ti-44.5Ni-5.0Cu-0.5V alloy, while two-stage elongation associated with the B2-B19-B19' transformation occurred in a Ti-43.0Ni-5.0Cu-2.0V alloy. The superelastic recovery ratio increased from 65.0 % to 86.1 % with increasing V content from 0.5 % to 2.0 % in solution treated specimens. The thermo-mechanically treated specimens showed the superelastic recovery ratio more than 95 %.

A tactile display is programmable device to be detected by human touch. It has great potential applications in the field of virtual environment. The current research is the first step to develop a programmable tactile array based on ER/MR fluid technology. Prototypes of display incorporating controllable fluids such as electrrheological (ER) fluid and magnetorheological (MR) fluid have been developed and investigated. Surface force responses of these tactile displays under various electric/magnetic fields have been measured while a probe moving across the upper surface. As the applied external electric or magnetic field varied, the sensed surface profiles changed in synchronisation with the field strength. With the controllable fluid actuator, the displayed surface information is stable and repeatable.

Structure design and parameters selection are crucial steps in developing magnetorheological fluid (MRF) damper for vehicle semi-active suspension system. Most traditional methods for deciding structure parameters by experiential expressions are unilateral and imprecise. In this paper, a multiobjective evolutionary optimization approach will be used to solve the optimization design problem. Based on Bingham fluid models, a structure design for MRF damper with shearing valve mode is completed for vehicle suspension. To reduce the dynamic response time and to enlarge the range the controllable damping force are taken as the optimization objectives. Three crucial parameters, including gap width, effective axial pole length and coil turns number are taken as optimization variables, a hybrid evolutionary algorithm combining particle swarm optimization (PSO) and crossover is employed to search for the Pareto solutions, According to the optimized results, a new type MRF damper design is accomplished for a pickup truck suspension system. The proposed method and analysis present a beneficial reference for MRF damper design.

In this paper, the response time of one magnetorheological fluid (MR) damper with maximum damping force of 250kN was tested. Experimental results show that, when electric current increase, response time is about 0.1 to 0.3s; when current decrease and not to zero, response time is about 0.2 to 0.3s, higher change of current induce longer of response time. Experimental results also show that, when electric current decrease to zero, response time is about 0.6 to 0.7s, which is much longer than expected. Further experiment results show that, if subtracting response of coil, when current increase, the response time is about 60 to 70ms, when current decrease and not to zero, the response time is about 140 to 150ms.

A home-made electrorheological (ER) fluid, known as ETSERF, has been created with suspension-based powders dispersed in silicon oil. Because of the special structure of their particles, ETSERF suspensions present a complex behavior. In the absence of an electric field, an ETSERF fluid will manifest a near-Newtonian behavior, but when an electric field is applied, it exhibits a pseudoplastic behavior with yield stress. The ER effect under DC electric fields has been experimentally investigated using both hydrous and anhydrous ER fluids. ER properties are strongly dependent on the dielectric properties of ETSERF suspensions and hydrous ER fluids have a high dielectric constant and a high relaxation frequency which show a strong electrorheological effect. The relationship between the electrorheological effect and the permittivity of ER fluids has also been extensively studied. Experimental results show that the interfacial polarization plays an important role in the electrorheological phenomenon. The ageing of ETSERF fluids was also studied and it was found that the dielectric properties (mainly the dielectric loss tangent) and ER properties are strongly related to the duration of ageing. A fresh ETSERF suspension exhibits a high relaxation frequency and a high dielectric constant. These results are mainly explained by the effect of interfacial polarizations.

Smart adaptive beams with 16-ply quasi-isotropic composite host and 10 nitinol wires prestrained to 5.5% were made in an autoclave with a purpose-made alignment device. The wires were eccentrically embedded in the axial direction. Beams of the same condition were duplicated and beams of different lengths were also made. The bending actuation of these adaptive beams was experimentally evaluated in a cantilever set-up by applying electric current to the nitinol wires. The evaluation showed that the present fabrication process was repeatable and reliable. For carbon/epoxy host, the maximum induced deflection was about 2 mm. This level of the end deflections could be due to limited load transfer associated with both high flexural rigidity of the host and semi-conductive carbon fibres. For E-glass/epoxy host, the maximum induced deflection was about 8 mm.

Based on the properties of thermoelectric cooler (TEC), a thermal analysis model for the thermo-smart structure of composite with TECs is built. Some parameters which affect the temperature distribution of the structure are designed, such as the location of TECs and the thermal boundary conditions. A temperature control system is designed for the thermo-smart structure and simulated in SIMULINK. The results of simulation indicate that the structure combined with PI controller performs greatly to temperature control. The applications of smart thermal structure on cooling design of computer chips and infrared stealth will benefit from the paper's results.

Microcapsules for self-healing applications were produced with a melamine-urea-formaldehyde (MUF) polymer shell containing two different healing agent candidates, ENB (5-ethylidene-2-norbornene) and ENB with 10 wt.% of a norbornene based crosslinking agent (CL), by in-situ polymerization in an oil-in-water emulsion. Relatively neat outer surfaces with minor roughness were observed on the MUF microcapsules under optical and scanning electron microscopy. Shell thickness of the capsules ranged from 700 to 900 nm. Particle size analysis of the microcapsules showed narrow size distributions with a mean diameter of 113 μm for ENB-filled and 122 μm for ENB+CL-filled microcapsules at an agitation rate of 500 rpm. The microcapsules were found to be thermally stable up to 300°C and exhibited a 10 to 15 % weight loss when isothermally held at 150°C for 2 hr from thermogravimetric analysis. Overall, these MUF microcapsules exhibited superior properties compared to the urea-formaldehyde (UF) microcapsules used extensively for self-healing composites to date. In addition, the manufacturing process of MUF microcapsules is much simpler than those made from UF. Additional advantages of MUF microcapsules for self-healing composites are discussed.

Microcapsule material can be controlled to perform various functions for its unique characteristics by changing certain environmental conditions, such as mechanical, chemical or electrical factors. In information-recording field, the applications of pressure-sensitive and heat-sensitive microcapsules have matured sufficiently. But limited by the size of thermal or pressure print head, these kinds of microcapsules can not realize the high image resolution printing. Based on microcapsule, as well as photo-responsive and heat-sensitive techniques, the photo-heat sensitive microcapsule can react quickly to very wavelength by photo-curing and can record the optical information of high-resolution. In this paper, a novel photo-heat sensitive microcapsule has been synthesized by interfacial polymerization method. Some factors that affected the size and distribution of microcapsule had been considered, the relationship between particle size distribution and the shearing speed was mainly discussed. In order to eliminate the photographic fog, the microencapsulation of developer was adopted in experiment. Optical response property of the photo-heat sensitive microcapsule was studied. The relationship curve between image density and exposing time was obtained. This new generation high resolution recording material can be used in optically controlled digital image reproduction field.

Surface Ni sulfides layers were formed on the surface of a Ti-50.0Ni alloy by reacting sulfur and Ni film deposited on the alloy, and then microstructures, transformation behavior, shape memory characteristics, superelasticity and electrochemical properties of a Ti-50.0Ni(at%) alloy with the sulfides were investigated. When Ni film deposited on a Ti-50.0Ni alloy was annealed under the sulfur pressure of 100 kPa at 623 K, sulfides layers consisted of NiS and NiS_1.97 were formed. When annealing was made at 648 K annealing with annealing time less than 0.9 ks, sulfides layers consisted of NiS and NiS_1.97 were formed also, while only NiS_1.97 was formed when it was made for 1.8 ks. When annealing was made at 673 K annealing with annealing time longer than 0.9 ks, only NiS_1.97 was formed. A Ti- 50.0Ni(at%) alloy with surface NiS_1.97 layer showed the two-stage B2-R-B19' transformation behavior, the perfect shape memory effect and a partial superelasticity with a superelastic recovery ratio of 78 %. NiS_1.97 cathode showed a clear discharge behavior with multi voltage plateaus. Discharge capacity of NiS_1.97 cathode decreased abruptly with increasing number of cycles up to 3, above which it decreased gradually.

The paper reports on the effect of Ca/P ratio (1.57, 1.67 and 1.87) on the densification behaviour of nanocrystalline hydroxyapatite (HA) prepared by a chemical precipitation method. Green compacts were prepared and sintered at temperatures ranging from 1000°C to 1350°C. The sintered samples were characterized to determine the HA phase stability, bulk density, hardness, fracture toughness and Young's modulus. XRD analysis revealed that the phase stability was not disrupted throughout the sintering regime employed for HA having Ca/P ratio of 1.57 and 1.67. However, secondary phases were observed for HA having a Ca/P ratio of 1.87 when sintered at high temperatures. In general, regardless of Ca/P ratio, the HA bodies achieved > 95% relative density when sintered at 1100°C-1250°C. The results indicated that the stoichiometric HA (Ca/P ratio = 1.67) exhibited the overall best properties, with the highest hardness of 7.23 GPa and fracture toughness of 1.28 MPam1/2 being attained when sintered at 1000°C-1050°C.

The objective of the present investigation was to study the effect of TiB₂ addition on sintering behavior and mechanical properties of pressureless-sintered B₄C ceramic. Different amounts of TiB₂, mainly 5 to 30wt% were added to the base material. Addition of 30wt% TiB₂ and sintering at 2050°C resulted in improving the density of the samples to about 98.5% of the theoretical density. The composite samples exhibited very good mechanical properties (hardness, flexural strength and fracture toughness). As the amount of TiB₂ was increased from 15 to 30, the mechanical properties were reduced, except for the fracture toughness, apparently due to excess amount of sintering aid in the specimen.

Ti-Ni-Cu alloys have been known to be attractive shape memory alloys for applications as actuators because of large transformation elongation and small transformation hysteresis. However, Cu addition exceeding 10at% makes the alloys brittle and spoils the formability. Arc melt overflow enables Ti-Ni-Cu alloys with high Cu-content to be fabricated into thin strips. Then, the shape memory alloy strips of Ti₅₀Ni₃₀Cu₂₀ and Ti₅₀Ni₂₅Cu₂₅ have been fabricated by arc melt overflow technique. Their microstructures and shape memory characteristics were investigated by means of XRD, optical microscopy and DSC. The microstructure of as-cast strips exhibited columnar grains normal to the strip surface. X-ray diffraction analysis showed that the martensitic transformation of B2-B19 occurred in the alloy strips. During thermal cyclic deformation with the applied stress of 60 MPa, transformation hysteresis and elongation associated with the B2-B19 transformation were observed to be 4.9°C and 1.8% in Ti₅₀Ni₃₀Cu₂₀ alloy strip and 3.5°C and 1.7% in Ti₅₀Ni₂₅Cu₂₅ alloy strip. The as-cast strip of Ti₅₀Ni₂₅Cu₂₅ alloy also showed a perfect superelasticity and its stress hysteresis was as small as 14 MPa. These mechanical properties and shape memory characteristics of the alloy strips were ascribed to B2-B19 transformation and the controlled microstructures produced by rapid solidification of the arc melt overflow process.

Hydroxyapatite (HA) porous materials for artifical human cancellous bone applications have been prepared via polymeric sponge method. Suspensions of the nanostructured hydroxyapatite powders were prepared with a fixed amount of distilled water and HA loading. After soaking cellulosic sponges into the suspension, the sponges were dried and then subjected to heat-treatment at 600°C, followed by sintering at 1250°C for 1 h. No alteration in structure found after sintering. The effect of sintering rate on the physical properties was also investigated in the study on two samples prepared based on a HA loading of 44% in the starting slurry. The study found that the average apparent density of the porous bodies were 2.03 g/cm³ and 1.69 g/cm³ with porosites of 36 and 46 % for the faster and the slower sintering, respectively. Morphological evaluation of the porous bodies shown that both the samples contained macropores of 200-500 μm diameter, which fulfill the minimum pore size of 100 μm as medically required. Excellent pore interconnectivity was found in all the samples. The measurement of compressive strength provided the values of 10.0 and 4.3 MPa for the faster and the slower sintering, respectively. It was also shown that the difference in sintering rate influenced the crystallinity of porous HA obtained.

In this paper we propose a system with the piezoelectric actuator by the single neuron adaptive PID controller for the grating tiling. Then the design of the control system as well as the control method by considering the nonlinearity of piezoelectric actuators is discussed. At last, close loop position examinations by the capacitive displacement sensor with nanometer scale precision are performed. The experimental results indicate that the system is working effectively. The system is provided with the characters of self-learning, easy calculating and adaptability as well as of a simple structure.

Flow measurement is the key method for R&D and operation monitoring of liquid rocket engine. Therefore, it is important to measure flux of low temperature liquid propellants for the liquid hydrogen/liquid oxygen or the liquid oxygen/kerosene rocket engine. Presently in China, the level meter and the turbine flowmeter are usually used in the experimentation of the liquid hydrogen/liquid oxygen rocket engine. The level meter can only scale average flux and the precision of the turbine flowmeter (the measuring wild point is 1.5%) can not be ensured due to the reason which there is not devices of low temperature real-time demarcation in China. Therefore, it is required to research the high performance low temperature flow measurement equipment and the vortex street flowmeter is selected because of its advantages. In the paper, some key techniques of low temperature vortex street flowmeter are researched from the design aspect. Firstly, the basic theoretical research of vortex street flowmeter includes signal detection method, shape of vortex producer and effects of dimension of vertex producer to vortex quality. Secondly, low temperature vortex street flowmeter adopts the method of piezoelectric components stress mode. As for the weakness of phase-change, lattice change and fragility for many piezoelectric materials in low temperature, it can not be fulfilled piezoelectric signal and mechanism performance under this condition. Some piezoelectric materials which can be used in low temperature are illustrated in the paper by lots of research in order for the farther research. The article places emphasis upon low temperature trait of piezoelectric materials, and the structure designs of signal detector and calculation of stress, electric charge quantity and heat transfer.

On the basis of the finite element mode of piezoelectric truss structure affixed piezoelectric patches on the surface, stable secular equation is proposed. Taking into consideration the mechanical-electric coupling effect under electric loads and mechanical loads, considering physical parameters and load coefficient of bar as stochastic variables , the formula of safety margins of piezoelectric truss instability is proposed,and the method of calculating the critical load coefficient derivative to variables is given. On the base of above research, stochastic finite element method is adopted to analyze the piezoelectric truss stable reliability,and the method of analyzing stable reliability index is given in different conditions.In the end,a example demonstrates validity of the method that is proposed in this paper. The analysis results shows that the reliability index of the piezoelectric trusses system can be improved by changing adscititious voltage and piezoelectric patches layout.The method provides references to analyze the stabile reliability for truss contained piezoelectric materials in the case of practical engineering.

In order to reduce the bend torsion coupling of seismic response, piezoelectric friction dampers are adopted as semi-active control devices for curved bridges. First, the space finite element model for curved bridge is established, and the piezoelectric friction dampers are placed at the bearing positions of two abutments. Second, the semi-active control equation of motion under multi-component and multi-support earthquake is derived, and different earthquake wave incident angles are considered. Several control algorithms, including passive, semi-active and active methods are compared, and in the end the semi-active limit Hrovat control algorithm is adopted. Finally, an effort is made to investigate the potential influence of multi-component and spatially variability of earthquake ground motion on decreasing amplitude effect of curved bridge using piezoelectric friction dampers. The results indicate that piezoelectric friction dampers are effective in reducing the response of curved bridges under multi-component multi-support earthquake, and semi-active limit Hrovat control algorithm is superior to the simple bang-bang control algorithm and the passive control method. Moreover, it is shown that the control effect of the particular curved bridge under earthquake loading is strongly affected by (a) the accuracy in modeling the properties of the incoming seismic wave field and (b) the curvature and overall irregularity parameters.

In 1996, after Ullakko et al. first reported a measurement of 0.2% strain along the [001] direction of a Ni₂MnGa single crystal when subjected to a magnetic field of 8KOe at 265K, the researches of ferromagnetic shape memory alloys became popular. The reversible strain induced by magnetic-field in Ni₂MnGa has been proved to be nearly 10% in a magnetic field of less than 1T, which is much higher than that of the rare-earth giant magnetostrictive alloys. But the high brittleness of Ni₂MnGa hinders its practical application. Therefore, the development of ferromagnetic shape memory alloys with good ductility is of primary importance. In this paper, the microstructure, martensitic transformation temperature, shape memory effect, as well as magnetic and mechanical properties of Co-Fe alloys were investigated by optical observation, X-ray diffraction, DSC, bending test and vibrating sample magnetometer. It was confirmed that the shape memory effect in Co-Fe alloys is associated with the fcc/hcp martensitic transformation. Moreover, Co-Fe alloys exhibit high saturation magnetization with the values of above 170 emu/g, which are much higher than that of Ni₂MnGa (66 emu/g). So the driving force under magnetic field will be large for Co-Fe alloys. Additionally, Co-Fe alloys possess good ductility for practical application with tensile elongation higher than 17.5%. All these results indicate that Co-Fe alloys are promising candidates for developing as ferromagnetic shape memory alloys.

Dynamic characteristics of composite laminates and composite isolators are studied in detail, and an optimum isolator for a 500Kg satellite is designed. Simulations are performed in order to determine the optimum geometry as well as dynamic characteristics of the isolator. It is found that increasing fiber angles of the ribs causes periodic sinusoidal change to the ratio and frequency. The first lateral frequency increases with thickness of skins, ribs and closure rings, but decreases with rib thickness. Thickness of closure rings produces little effect on the ratio. Based on these simulation results, isolator for satellite suppression is designed. The feasibility are verified by finite element analyses.

In order to overcome the interfacial stress concentrations of the traditional layered piezoelectric elements, functionally graded piezoelectric materials with material properties changing smoothly and continuously along certain direction have been developed. At present it has becoming a new research hotspot. Based on the three-dimensional elastic theory of piezoelectric materials and assuming that the mechanical and electric properties vary continuously along the thickness direction and have the same exponential distribution, the static analysis of functionally graded piezoelectric annular sectorial plates with simply supported radial edges and arbitrary circular edges is achieved in this paper using a semi-analytical method which makes use of the state space method along the graded direction and the one-dimensional differential quadrature method along the radial direction. The accuracy, convergence and superiority of the present method are demonstrated through numerical results. The effect of material graded index on the electromechanical coupling behavior of functionally graded piezoelectric annular sectorial plates is studied. The results obtained from the numerical example may be useful for the design of functionally graded piezoelectric annular sectorial plates.

The present work is aimed at the development of a new kind of ingredient heterogeneous shape memory composites, based on explosive welding, specifically designed to exhibit high damping in the wider temperature window. The DSC result shows that the synthesized shape memory composite still possesses the perfect shape memory effect, and the martensitic transformation temperature region has been broadened obviously. The micrograph shows that a straight interface is obtained after the hot rolling without any observable metallurgical defects. The damping properties have been characterized by mechanical spectroscopy as a function of temperature between -120 and 130°C, test frequency between 0.5 and 1.5 Hz, and strain amplitude at 5×10^-5. The internal friction results show that there appear two damping peaks during the reverse martensitic transformation region and the height of damping peaks increase with the test frequency decreasing. Moreover, the abnormal behavior of the relaxation damping peak occurs during the measurement of the composite at the low temperature range, which the height of relaxation damping peak increases with the test frequency increasing. This result of our work disagrees with the rule of relaxation peak vs. test frequency which has been proposed through investigating shape memory alloy in published papers.

A novel kind of thermoresponsive shape memory fiber was prepared by mixing the P(SA-co-AA) copolymers of stearyl acrylate (SA), and acrylic acid (AA), with PVA polyvinyl alcohol through chemically crosslinking after spinning. The molecular structure, thermomechanical properties and shape memory behaviors were investigated. It was found that the mixed P(SA-co-AA)/PVA fibers had crystalline structures and showed a dramatic change in Young's modulus at melting temperature (Tm) due to the reversible order-disorder transition. The mixed P(SA-co-AA)/PVA fibers also showed a good shape memory effect, through which the deformed fibers could recover to their original shapes and sizes within 40 seconds after they were heated above their Tm again.

NiTi shape memory alloy is a temperature sensitive material with non-linear mechanical properties and good biocompatibility, which can be used for medical devices such as stent, catheter guide wire and orthodontic wire. The majority of nitinol stents are of the self-expanding type basing on the superelasticity. Nitinol stents are shape set into the open condition and compressed and inserted into the delivery catheter. Additional the shape-setting treatment can be used as a tool to accurately tune the transformation temperatures and mechanical properties. In this study, different heat treatments have been performed on the Ti-50.7at%Ni alloy wires. And results of shape-setting, austenite transformation finish temperature and non-linear mechanical property of NiTi shape memory alloy at body temperature have been investigated. The experimental results show that the proper shape-setting temperature should be chosen between 450-550 °C. And the shape-setting results were stabilization when the NiTi wires were constrain-treated at 500 and 550°C and ageing time longer than 10 minutes. The austenite finish temperatures increased with ageing time and increased first and then decreased with ageing temperature. The peak values were obtained at 400°C. When the heat treatments was performed at the same temperature, both the upper plateau stresses and lower plateau stresses decreased with the ageing time. Most of treated nitinol wires owned good recovery ability at body temperature and the permanent sets were less than 0.05% when short time ageing treatment was performed at 500°C.

Microstructure of an Fe-Mn-Si-Cr-Ni shape memory alloy (SMA) after being TIG (tungsten-insert gas welding) welded was investigated using scanning electron microscope (SEM) and X-ray diffractometer. The results show that dendrite crystals composed of cellular sub-structures form in the weld zone due to remelting. There is no obvious change in microstructure of the heat-affected zone (HAZ) except for some degree of growth of austenite grains. Since both the weld zone and HAZ consist of single phase of austenite (γ), pre-strain can still induce the γ→ε martensite transformation in welding joints of the alloy. Effect of TIG welding on shape recovery characteristics of the alloy was examined by bending tests and it was found that the TIG-welded Fe-Mn-Si-Cr-Ni alloy exhibits almost the same excellent SME as the base material.

Tapering fiber grating is a special designed fiber grating with some characters. The fiber tapering broadens the bandwidth of the grating. The strain response of the tapering gratings is somewhat different from the standard FBG. To fabricate the tapering fiber gratings, the fiber-fusing machine is utilized to pull the fiber when fiber is heated. The tapering fiber has a thin waist in the middle of the fiber to be exposed under 248nm laser. A normal phase mask is used in experiment. Because tapering process of the fiber, the bandwidth of the reflecting spectrum is broadened. There are some fabrication conditions of the tapering fiber gratings including the fusion time, loading position and exposing time. Different tapering fiber gratings have different strain response especially strain field response. A series of experiments have been done to research on the application potential of tapering fiber gratings in SHM (Structure Health Monitoring).

The application of SOI wafer in integrated optical components provides a novel method of increasing the density of integration, as well as reducing unit cost. This paper designed a new kind of waveguides coupler for an integrated optical transceiver unit of an interferometric fiber optic gyroscope system. Based on effective index method and beam propagation method (BPM), mathematic model of the waveguides coupler was founded, and theory calculation and analysis were finished for key parameters, such as coupling ratio, effective coupling length, division radio and returning loss, etc. Also these parameters were optimized in practice coupler design which used in integrated optical transceiver. The design results indicated that its division radio is 50%:50%, coupler core size is 6μm×5.5μm, length of the chip is 25mm and width between two export ports of the waveguides is 400μm. With electron beam lithography machine the mask of silicon-on-insulator (SOI) waveguides coupler was fabricated. The mask fabrication parameters were developed and optimized in this paper. Detect results shown that this optical waveguides coupler can be used in integrated optical transceiver unit for the interferometric fiber optic gyroscope system. This result can provide significant theory basic for research on high integrated, high reliably, low cost integrated optical components used for interferometric fiber optic gyroscope.

Polyaniline/PP conductive fiber was obtained by in-situ adsorption polymerization. In this work, we discussed the influence of these reaction factors such as adulteration acid concentration, oxidizer concentration, polyaniline monomer content and reaction time to the polymerization and conduct property. In the meanwhile, surface handling with plasma have also been compared for examining the change of polymerization and conduct property. FT-IR spectra analysis and the physic mechanical properties have been used to investigate the structure and properties of conductive fibers. The result shows that with this method of polymerization the conductive property is superior and the conductivity can be reached by 4.5KΩ.

The fiber optic gyroscope (FOG) is a solid-state rotation sensor which is currently employed in inertial navigation systems. Highly birefringence fibers can be used to as polarization-maintaining (PM) fiber in FOG. PM fibers can reduce both the drift polarization cross coupling created polarizer and drift due to the earth's magnetic field via the Faraday Effect. But when the two beams polarized along fast and slow axes traverse the PM fiber, interference between the two counter-propagating beams may be influenced by the dispersive nature of the modal birefringence. The modulus of the degree of coherence, |γ| with respect to the interference between the two orthogonally polarized waves, may impose a severe restriction on the phase difference detection. Hence the problem of the signal to noise radio with respect to the received signal may be strongly influenced by the modulus of the degree of coherence. In this paper interference between two orthogonally polarized modes traversing a highly birefringence fiber is investigated theoretically and experimentally. Simulation results show that the detection sensitivity of fiber optic gyroscope employing highly birefringence fiber is degraded as the chromatic dispersion difference between the two mode increases. The result obtained here will provide useful data for the design and performance evaluation of fiber-optic sensors employing polarization-maintaining fibers.