Abstract
We have investigated the formation of electron beam-generated (EBG) plasma near a dielectric (ceramic) target and an insulated metal target, and the compensation of the negative charge ...accumulated on the insulated metal target when the targets are irradiated by an intense pulsed electron beam in the forevacuum pressure range (4–15 Pa). It is shown that the density of the EBG plasma near the irradiated ceramic target (or the irradiated insulated metal target) is greater than the plasma density for a beam propagating freely in a vacuum chamber (or for the grounded metal target). The EBG plasma near the target is formed with a certain delay with respect to the electron beam current pulse, because of which the negative potential of the insulated target is also compensated by a delay. The delay time in the formation of the EBG plasma and in the compensation of the target negative potential decreases with increasing gas pressure. Expressions have been proposed for estimating this delay time.
We present the results of applying the Lagrangian methods to study the fine dynamic structure of the stratospheric polar vortex in the winter–spring of 2019–2020. Characteristics of the vortex ...structure for this winter are compared with those of a strong polar vortex and the winter of 2018–2019, when the vortex was weak. Due to the low activity of planetary waves, the polar vortex in 2019–2020 remained stable until the end of April, which created the conditions for record ozone destruction in the Arctic. We present variations of the horizontal dynamic structure obtained using reverse domain filling (RDF) and the vortex strength represented as an M function depending on time and altitude. Variations in ozone and thermodynamic parameters averaged over the ensemble of trajectories inside the vortex using the ERA5 reanalysis data are also presented.
To achieve better agreement of simulated Arctic winter stratospheric dynamic with observations assimilation procedure nudging was incorporated in CCM SOCOL. Trajectories based on SOCOL output winds ...demonstrate the reasonable agreement with trajectories based on reanalysis data inside the polar vortex and can be used for analysis and forecast of ozone related processes in winter-spring seasons. Obtained results of several recent major Arctic SSW events analysis show that CCM SOCOL could be used for SSW forecast over the period up to 8 days.
A method to assess the gas resistance of woody plants was developed based on the level of inhibition of the photosynthetic activity of leaves exposed to toxic gases in the laboratory and could be ...used to identify plants resistant to environmental pollution for further practical and breeding use. The effective quantum yield of photosystem II was used as an indicator of genotype tolerance. The sensitivity of the indicator was sufficient to differentiate control and experimental variants. The objects under study were ranked according to the degree of gas resistance. Recommendations were given for the practical application of the new method.
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The features of the morphology and magnetic properties of Ni nanowire arrays have been studied. Aluminum oxide matrices are used as a template for electrolytic deposition of nanowires. The matrices ...are obtained by anodizing the aluminum films with a thickness of 2 μm that are formed on glass substrates by high frequency ion sputtering. Electrochemical deposition of the metal is carried out using direct and alternating currents. Morphology and microstructure studies show that the nanowire arrays are polycrystalline and have a branched dendritic structure due to the morphological features of aluminum oxide matrices. A relationship between the magnetization reversal patterns and the modes of electrodeposition of Ni nanowire arrays is established. The process of magnetization reversal of an array of this kind of structures is simulated.
The research was aimed at evaluating sweet cherry forms on a complex of economically valuable traits and the allocation of promising genotypes for further use in breeding and production. The forms of ...sweet cherries grow in Michurinsk city of Tambov region. The study of frost resistance was carried out in laboratory conditions. Annual branches were frosted for 12 hours at -32°C and -35°C. Reproductive buds in all studied forms were characterized by reversible damage (less than 3 points) at temperature regime -32°C and complete death at -35°C. 10-117 form was characterized by -35°C frost resistance in the middle of winter, in which the freezing degree of annual branches tissues and vegetative buds did not exceed 2 points. Over the years of research, elites 4/8-24, 10-115, 7-38, 10-117, 6-87, 4/9-15, 7-5 possessed resistance to moniliosis and coccomycosis (the damage degree not more than 2 points). The highest yield (9.75-9.84 t/ha) on average over three years was shown by forms 4/8-24, 7-38, 7-5. Yield at the control level was noted in forms 6-87, 4/9-15, 10-115. Elite forms 4/9-15, 7-38 were characterized by the largest mass of fruits, significantly exceeding the control variety. The average weight amounted to 7.3 and 7.2 g, and the maximum was 9.4 and 8.4 g respectively. Forms 4/8-24, 4/9-15, 7-38 combined the dessert taste of fruits (tasting assessment of 4.6-4.8 points), very juicy and dense pulp.
The estimates of chemical ozone depletion in winter-spring seasons are given for the Arctic stratosphere based on long-term observations of the vertical distribution of ozone. The features and ...possible causes for an unusually strong and stable stratospheric polar vortex in the Arctic in the winter 2019/2020, that led to a record ozone loss in recent years, and the dynamic processes associated with this polar vortex are analyzed. The TRACAO trajectory model and ERA5 reanalysis are used for the comparative analysis of ozone depletion in the polar vortex in the winter-spring seasons 2010/2011 and 2019/2020.
Trajectory Modeling of the Middle Atmosphere Lukyanov, A. N.; Gan’shin, A. V.; Yushkov, V. A. ...
Russian meteorology and hydrology,
09/2021, Letnik:
46, Številka:
9
Journal Article
Recenzirano
A short description and some applications of the trajectory and dispersion models developed in Central Aerological Observatory (CAO) for studying the stratospheric and tropospheric transport of ...pollutants are presented. The TRACAO trajectory model is applied to investigate the processes related to the ozone depletion in the winter polar stratosphere, in order to study the mid-latitude stratosphere–troposphere exchange, as well as to analyze balloon and aircraft (M55 “Geophysics,” Yak-42D “Roshydromet”) observations. Then based on the TRACAO, the GLADIM dispersion model that simulates trajectories of the set of particles with the eddy diffusion parameterization and determines the pollutant concentration at the regular grid points, was developed. The dispersion model was applied to simulate volcanic ash dispersion and carbon dioxide profile reconstruction. The model validation was done by comparisons with the results of the widely used FLEXPART model. Nowadays these models are used at the “Middle Atmosphere” Regional Information and Analytic Center established in CAO.
Nanodispersed TiO
2
consisting of anatase and brookite phases in a ratio of 3 : 1 is obtained by the sol–gel method from titanium(IV) butoxide at a temperature below 100°C. X-ray diffraction, ...transmission electron microscopy, and Raman spectroscopy are used to show that the size of anatase particles is about 6 nm, and brookite particles consist of a crystal core, 4 nm in diameter, surrounded by an amorphous shell. Compared with the commercial Degussa P25 photocatalyst, which consists of the anatase and rutile phases in the same 3 : 1 ratio, the resulting TiO
2
exhibits an increased photoactivity in hydroquinone oxidation. Quantum chemical modeling of anatase and brookite surfaces as well as their interface does not reveal the specific features of their electronic structure. This fact is indicative of the amorphous phase as an active participant in the transfer of charge carriers in the photocatalytic process.
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•The MCE of Gd2O3 nanoparticles obtained by spark discharge has been studied.•Variations of the spark discharge parameters changes the structure of nanoparticles.•The magnitude of the ...MCE depends on the structure of the Gd2O3 nanoparticles.•Gd2O3 nanoparticles is a promising material for cryogenic magnetic cooling.•Spark discharge is a useful technology for manufacturing of Gd2O3 nanoparticles.
Several batches of nanoparticles of gadolinium oxide Gd2O3 were obtained by the electrophysical spark discharge (ESD) method using selected variations of the value of the energy supplied to the discharge gap. The change of the charge voltage led to a change in the energy supplied to the discharge gap in the range of 3 J to 55 J. The average size of spark discharge nanoparticles in all cases was close to 8 nm in accordance with low-temperature nitrogen adsorption data. Gd2O3 nanoparticles contained two crystalline phases (cubic and monoclinic), the amount of which varied within certain limits by changing the parameters of the spark discharge. The obtained maximum values of the magnetic entropy change ΔSM of the studied ESD Gd2O3 nanoparticles with a monoclinic phase content of less than 40 wt% are not inferior to the value of ΔSM of Gd2O3 nanoparticles obtained by chemical methods. The spark discharge technique seems to be a promising technology for manufacturing of gadolinium oxide nanoparticles applications for the magnetic cooling systems of cryogenic refrigeration.
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