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1.
V. A. Alekseev 《Optics and Spectroscopy》2004,96(4):492-496
The absorption spectra of Xe + CF4 and Kr + CF4 mixtures in the vacuum ultraviolet region are presented. A considerable broadening of the short-wavelength wings of the atomic absorption lines is explained by a repulsive character of the Rg*-CF4 interaction potential. This repulsive character is also considered to be the most probable reason for the anomalously small cross sections of the quenching of electronically excited atoms of rare gases by CF4 molecules. The influence of CF4 on the emission rate of the trapped resonance radiation of Xe from the cell is discussed. 相似文献
2.
3.
N. I. Alekseev V. B. Kaplan A. M. Martsinovskii I. I. Stolyarov 《Technical Physics》1997,42(6):599-605
Results are presented from a systematic investigation of the conditions under which anomalously high rates of plasma generation
are observed in the anode region of a low-voltage Knudsen arc in grid plasma switch elements. The phenomenon develops over
a wide range of currents and switched voltages under conditions for which the plasma density in the cathode-grid region is
noticeably higher than the density in the anode region. and its onset is characterized by a pronounced pressure threshold
of ∼2×10−2 Torr. The results are analyzed from the standpoint of the possible mechanisms for anomalous plasma generation — collisional
nonresonance diffusion of electrons in velocity space, leading to enrichment of the distribution function in fast particles,
and the collapse of Langmuir waves in the gap at the high energies of the beam produced when the wires of the grid are bridged
by the quenching pulse and and the current is blocked.
Zh. Tekh. Fiz. 67, 15–21 (June 1997) 相似文献
4.
5.
F. Klappenberger K. N. Alekseev K. F. Renk R. Scheuerer E. Schomburg S. J. Allen G. R. Ramian J. S. S. Scott A. Kovsh V. Ustinov A. Zhukov 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,39(4):483-489
We report an experimental study indicating ultrafast creation and annihilation of space-charge domains in a semiconductor superlattice under the action of a THz field. Our experiment was performed for an InGaAs/InAlAs superlattice with the conduction electrons undergoing miniband transport. We applied to a superlattice a dc bias that was slightly smaller than a critical bias necessary for the formation of space-charge domains caused by a static negative differential conductivity. Additionally subjecting the superlattice to a strong THz field, resulted in a dc transport governed by the formation of domains if the frequency of the field was smaller than an upper frequency limit (~3 THz). From this frequency limit for the creation and annihilation of domains we determined the characteristic time of the domain buildup. Our analysis shows that the buildup time of domains in a wide miniband and heavily doped superlattice is limited by the relaxation time due to scattering of the miniband electrons at polar optic phonons. Our results are of importance for both an understanding of ultrafast dynamics of pattern formation in nanostructures and the development of THz electronic devices.Received: 25 March 2004, Published online: 23 July 2004PACS:
72.20.Ht High-field and nonlinear effects - 72.30. + q High-frequency effects; plasma effects - 73.21.Cd SuperlatticesK.N. Alekseev: Permanent address: Department of Physical Sciences, P.O. Box 3000, University of Oulu FIN-90014, Finland. 相似文献
6.
A. I. Alekseev 《Few-Body Systems》2006,40(1-2):57-70
Based on a study of the analytic running coupling obtained from the standard perturbation-theory results up to four-loop order,
the QCD “synthetic” running coupling αsyn is built. In so doing the perturbative time-like discontinuity is preserved and nonperturbative contributions not only remove
the nonphysical singularities of the perturbation theory in the infrared region but also decrease rapidly in the ultraviolet
region. In the framework of the approach, on the one hand, the running coupling is enhanced at zero and, on the other hand,
the dynamical gluon mass m
g
arises. Fixing the parameters which characterize the infrared enhancement corresponding to the string tension σ and normalization,
say, at M
τ completely define the synthetic running coupling. In this case the dynamical gluon mass appears to be fixed and the higher-loop
stabilization property of m
g
is observed. For σ = (0.42 GeV)2 and αsyn(M
τ
2) = 0.33 ± 0.01 it is obtained that m
g
= 530 ± 80 MeV.
Deceased 相似文献
7.
8.
I. G. Alekseev P. E. Budkovsky V. P. Kanavets L. I. Koroleva B. V. Morozov V. M. Nesterov V. V. Ryltsov D. N. Svirida A. D. Sulimov V. V. Zhurkin Yu. A. Beloglazov A. I. Kovalev S. P. Kruglov D. V. Novinsky V. A. Shchedrov V. V. Sumachev V. Yu. Trautman N. A. Bazhanov E. I. Bunyatova 《Physics of Atomic Nuclei》2002,65(2):220-228
New experimental data on the spin-rotation parameters A and R measured for elastic π ± p scattering in the resonance region and on the asymmetry in pC scattering at primary momenta in the range 1.35–2.02 GeV/c, as well as in quasielastic proton scattering on nuclei in the same momentum range, are summarized. All these data were recently obtained by using the proton synchrotron installed at the Institute of Theoretical and Experimental Physics (ITEP, Moscow). The spectrum and features of seven isospin-3/2 baryon resonances that form a peak in the total cross section at a c.m. energy of 1.9 GeV are analyzed on the basis of new data on the parameters A and R, and the results of this analysis are presented. The experiments surveyed in this article were performed by a collaboration of researchers from ITEP and the Petersburg Nuclear Physics Institute (PNPI, Gatchina), the ITEP-PNPI collaboration. 相似文献
9.
I. E. Nemirovskaya A. N. Grechenko A. M. Alekseev V. V. Lunin 《Journal of Structural Chemistry》1991,32(5):680-686
State Institute of the Nitrogen Industry. M. V. Lomonosov State University, Moscow. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 5, pp. 74–81, September–October, 1991. 相似文献
10.
V. A. Alekseev 《Optics and Spectroscopy》2002,93(3):334-339
To extend the capabilities of the existing spectroscopic methods of investigation and diagnostics of gaseous media, we consider a macroscopic effect of an increase in the rate of spontaneous emission, which results in the transition of a considerable part of excited molecules to lower-lying optically accessible states with light pulse emission along the direction of propagation of the exciting laser radiation. As an application of the effect of amplified spontaneous emission, we propose the population with its help of optically inaccessible electronic states of atoms and molecules. 相似文献