The article considers the prospects of introducing an optical measurement channel into the composition of a complex radiophysical system of remote sensing of the atmosphere. Lidar systems of atmospheric monitoring for distribution of aerosol and chemical composition of air, as well as wind speed and direction are the most widespread. The study of aerosol and gas composition of air is especially important in the tasks of environmental monitoring of areas associated with hazardous industries and global transport of pollutants, including greenhouse gases. Molecular (gas) atmosphere at laser sounding is manifested in absorption, in the phenomena of molecular (Rayleigh), Raman, resonance scattering and fluorescence. These phenomena differ in their intensity or interaction cross sections and, consequently, in the possibilities for reliable registration of signals. Atmospheric parameters such as wind speed and direction, visibility, density and height of cloud layers change both temporally and spatially, which can lead to the formation of dangerous meteorological phenomena. Atmospheric aerosol plays an important role in climate change, so monitoring its composition and dynamics is essential for assessing climate change on a global scale.
The paper presents the results of experimental studies of variants of construction of intermediate frequency paths of microwave radiometric systems based on the traditional scheme of construction using copper coaxial transmission lines of intermediate frequency signals of microwave radiometric receivers and promising radiophotonic fiber-optic transmission line of microwave signals with internal modulation. The aim of the work is to evaluate the possibility of realization of the radiophotonic path for transmission of intermediate frequency signals as a part of perspective microwave radiometric systems for remote sensing of the atmosphere. The objectives of the work are to analyze the characteristics of radiophotonic transmitting and receiving modules as part of the intermediate frequency path of a multi-frequency microwave radiometric system for remote sensing of the atmosphere in comparison with a coaxial radio-frequency transmission line.
The cultures of filamentous fungi in aquatic medium release fluorescent metabolites (FM) with emission spectra that closely match the typical fluorescence bands found for soil extracts and aquatic fluorescent dissolved organic matter (FDOM). FM released from some fungal cultures show as well comparable values of fluorescent quantum yield, the blue shift of emission spectra excited in the UV, and a very close match of ultraviolet–visible absorbance spectral curves related to soil and aquatic FDOM, further strengthening the similarity of fluorophores in those aquatic material. Given the importance of microscopic filamentous fungi in the global carbon cycle, our results indicate that filamentous fungi are likely to be important sources of aquatic and soil FDOM of microbial origin.
The article presents the research results of the modern radar complexes modernization possibility due to the use of methods and elements of microwave photonics in the devices of signals formation for heterodynes and transmitters of radar stations. Application of high potential active phased antenna array with multichannel spatial processing of received signals, based on the use of microwave photonics technology, will significantly improve the basic tactical and technical characteristics of the radar: range resolution, information value, detection range, noise immunity and power consumption. Realization of the listed advantages is reached by introduction of elements, functional knots and components of active phased antenna array subsystems because of electro-optical modulators and demodulators, sources and receivers of optical radiation, optical signal amplifiers, optical delay lines, fiber-optic, and optical passive elements.
Soil fungi are actively involved in the processes of humic substances synthesis, transformation and mineralization due to production of extracellular nonspecific oxidative enzymes. The work was aimed to evaluate using spectral methods transformation dynamics for the humic product (HP) from lignosulfonate (HPligno) by filamentous soil fungal cultures Alternaria alternata and Trichoderma harzianum. Experiments showed that direct spectroscopic study of HPligno introduced into the nutrient medium and its transformation during fungal growth is challenging due to strong absorption of light by nutrient medium, development of absorbing fungal metabolites, partial utilization and destruction of HP by fungi and therefore due to the need to register tiny changes in overlapping bands. To accomplish that task we proposed a novel algorithm for processing the absorption spectra, which has not previously been used to study fungal cultures. We calculated the second-order derivative in respect to wavelength for absorption spectra measured during fungal growth and found characteristic "patterns" for introduced HP: a maximum at 270-285 and a minimum within 290-300 nm. The spectral index determined from amplitudes in the second-order derivative spectrum reflects the relative content of HP in the nutrient medium in presence of other absorbing components. We resume that two fungal strains utilized HPligno in the 0,02 and 0,1% concentrations better at 30 g/L sucrose than at 3 g/L in the medium. Thus the second-order differentiated absorption spectra helped to quantify degradation of the HPligno during fungal growth.
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