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21.
The elastic deformation behavior and the load-carrying capacity of unidirectional carbon fiber laminates under static loading
at room and cryogenic (down to 77 K) temperatures are investigated. The possible ways of predicting their elastic and strength
characteristics proceeding from the volume content and mechanical parameters of fibers and matrix are analyzed.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 5, pp. 583–598, September–October, 2006. 相似文献
22.
Zemtsov A. A. Kondratyev N. S. Levin V. V. Struchkova M. I. Dilman A. D. 《Russian Chemical Bulletin》2016,65(11):2760-2762
Russian Chemical Bulletin - gem-Difluoro-substituted organozinc reagents undergo cross-coupling reaction with propargyl halides in the presence of catalytic amounts of copper cyanide. The reaction... 相似文献
23.
A. I. Zakharov Yu. K. Zemtsov I. V. Marinov A. P. Osipov 《Journal of Applied Mechanics and Technical Physics》1976,17(3):304-308
It is known from experiments [1–3] that the velocity of streamers, induced in the center of the interelectrode gap and propagating to the electrodes under conditions when the streamer length is comparable with the distance between the electrodes, increases linearly as the streamer length increases. This relationship is in qualitative agreement with theory [4], Nevertheless, the velocity of streamers starting from the electrodes and propagating in a long interelectrode gap remains practically constant during the whole propagation process [5, 6], In the case of short gaps (2–5 cm), constancy of the velocity is observed during the stage of the process when the length of the streamer is much less (20%) than the length of the gap [7], Since the electric field at its end controls the streamer propagation, the constancy of the streamer velocity indicates that the controlling field is constant under these conditions. A number of theoretical models were proposed in [8–13] which describe uniformly moving anode- and cathode-directed streamers (henceforth called anode and cathode streamers). Comparison of experimental data with the corresponding theoretical model enables one to determine the streamer parameters: the electric field, the charged-particle density, the current density, the channel radius, etc. In the case of an anode streamer in Xe an attempt at such a comparison was made, in particular, in [6]. However, the lack of reliable data on the value of the drift velocity and the diffusion coefficient of electrons in Xe for E/p (102 – 103) V/cm · mm Hg allowed only rough estimates to be made. In this paper a numerical calculation is made of the drift velocity, the diffusion coefficient of electrons in Xe, and the rate of excitation of Xe atoms in the resonance level in the range of values of E/p (101–103) V cm · mm Hg, and the volt-ampere characteristic of the breakdown is measured under conditions described in [6] (p0=300 mm Hg and E 104–105 V/cm). Using these results, the formulas for the velocity of anode [12] and cathode [13] streamers, and experimental data [6], the parameters of the streamers studied in [6] are determined.Translated from Zhurnal Prikladnoi Meknaniki i Tekhmcheskoi Fiziki, No. 3, pp. 6–11, May–June, 1976.The authors thank A. T. Rakhimov and A. N. Starostin for useful discussions, and A. V. Markov for help with the experiments. 相似文献
24.
Yu. K. Zemtsov A. Yu. Sechin A. N. Starostin A. G. Leonov D. I. Chekhov 《JETP Letters》1997,65(11):839-844
The purely thermal infrared emission spectra of a resonance medium (sodium vapor) are investigated experimentally. It is shown
that the emission intensity in the 2–3 μm range at temperatures of 600–1200 K is several orders of magnitude higher than the
intensity obtained from the standard theory of resonance radiation transfer. This phenomenon can be conventionally termed
an “infrared catastrophe.” The form of the recorded spectra and the absolute intensity of the emission in both the infrared
and visible regions of the spectrum are in agreement with the theory developed by Yu. L. Zemtsov and A. M. Starostin, Zh.
éksp. Teor. Fiz. 103, 345 (1993) [JETP 76, 186 (1993)], in which the Boltzmann spectral distribution of the population of the resonance level is proportional to exp(−ħω/T).
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 11, 807–811 (10 June 1997) 相似文献
25.
Kucher N. K. Dveyrin A. Z. Zarazovskii M. N. Zemtsov M. P. 《Mechanics of Composite Materials》2004,40(3):217-226
The regularities of elastic deformation of multilayered fiberglass plastics reinforced with a fabric of sateen weave are studied. The effect of cooling to 77 K on the averaged elastic characteristics of the orthotropic material is analyzed. The efficiency of mathematical modeling in calculating the stiffness and compliance parameters of the woven composites based on the geometry and mechanical properties of their constituents is investigated. 相似文献
26.
G. P. Karpacheva K. A. Bagdasarova G. N. Bondarenko L. M. Zemtsov D. G. Muratov N. S. Perov 《Polymer Science Series A》2009,51(11-12):1297-1302
The influence of the ligand on the formation of a system of conjugated-bonds at the initial steps of IR-pyrolysis of composites based on polyacrylonitrile and Co(C5H7O2)2 or CoCl2 is demonstrated. An increase in IR-irradiation intensity leads to the formation of nanocomposites that contain nanoparticles of cobalt dispersed in a graphite-like matrix. Superparamagnetic Co particles are shown to make a significant contribution to the magnetic behavior of the nanocomposites prepared. The dependence of the electric properties of the composites on the synthesis conditions is investigated, and the role of Co nanoparticles in the growth of electrical conductivity is shown. 相似文献
27.
M. N. Efimov E. L. Dzidziguri E. N. Sidorova K. O. Chuprunov L. M. Zemtsov G. P. Karpacheva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(7):1175-1178
Nanosized Pt-Ru alloy and Pt13Ru27 intermetallic compound particles dispersed in a carbon matrix were obtained for the first time directly during the preparation of the composite. The alloying of the Pt and Ru particles occurred at IR pyrolysis intensities corresponding to temperatures above 700°C over the whole homogeneity range of solid solutions based on platinum. Metallic nanoparticles were round-shaped (the mean size 6–8 nm) and had a narrow particle-size distribution. 相似文献
28.
E. L. Dzidziguri E. N. Sidorova K. A. Bagdasarova L. M. Zemtsov G. P. Karpacheva 《Crystallography Reports》2008,53(2):316-319
The effect of the IR-pyrolysis intensity on the phase formation and structure of Co nanoparticles in a matrix of IR-pyrolyzed polyacrylonitrile has been investigated. 相似文献
29.
I. A. Kirovskaya A. E. Zemtsov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(4):654-658
The adsorption properties of GaAs-CdS solid solutions and the constituent binary systems with respect to CO and NH3 were studies by piezoquartz microweighing, temperature-programmed desorption, and IR spectroscopy. On the basis of an analysis of the measured α p = f(T), α T = f(p), and α T = f(t) dependences, the thermodynamic and kinetic characteristics of adsorption, earlier obtained acid-base and other physicochemical characteristics of adsorbents, and the electronic properties of the adsorbate molecules, the mechanism and regularities of the adsorption processes at various conditions and compositions of the system were established. A comparison of the adsorption properties of the GaAs and CdS individual binary compounds with their (GaAs)x(CdS)1?x solutions, multicomponent systems, revealed common and distinctive features. Optimal compositions of adsorbents suitable for manufacturing primary transducers in sensors for medical and environmental purposes were determined. 相似文献
30.
Yu. K. Zemtsov A. Yu. Sechin A. N. Starostin A. G. Leonov A. A. Rudenko D. I. Chekhov 《Journal of Experimental and Theoretical Physics》1998,87(1):76-86
The purely thermal visible and infrared radiation emitted by a dense resonant medium (sodium vapor) heated nonuniformly to
temperatures of 600–1200 K was investigated experimentally for the first time under conditions where the photon mean free
path is comparable with the emission wavelength. The profile of the recorded spectra and the absolute luminescence intensities
in the different spectral ranges show good agreement with the results of a numerical simulation using a previously developed
theory of resonance radiation transport which assumes a Boltzmann spectral distribution of the resonant level population proportional
to exp(−ℏω/T). The self-reversed resonant sodium line exhibited strong asymmetry and it was shown that under certain conditions, the luminescence
spectrum of the medium may exhibit an additional broad peak on the far “red” limb of the resonance line. Calculations and
measurements demonstrated that the intensity of the thermal emission of sodium vapor at this red peak is several orders of
magnitude higher than that obtained from the standard theory of resonance radiation transport. This effect is arbitrarily
termed an infrared “ catastrophe.” It is noted that in a solar corona plasma and in gas-discharge lamps, the far red limbs
of the resonant lines may make a substantial contribution to the total luminescence intensity and in some cases, considerably
exceed the intensity of the photorecombination and bremsstrahlung continuum.
Zh. éksp. Teor. Fiz. 114, 135–154 (July 1998) 相似文献