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1.
Volodymyr Malyutenko Vitalii Borblik Victor Vainberg 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):563
An all-optical approach to convert terahertz radiation (THz, wavelength λ1) into infrared (IR, peak wavelength λ2) is presented. We show that this up-conversion process is due to the photon drag effect induced by the THz radiation in intrinsic narrow-gap semiconductors followed by spatial redistribution of current carriers and band-to-band radiative recombination. The process results in non-selective high-speed (ns range rise/fall times) IR imaging of positive (conventional luminescence) and/or negative (negative luminescence) contrasts. Estimates made for an InSb pixelless converter at 300 K and moderate THz intensity (kW/cm2) show that this up-conversion process (with λ1/λ2>102) can be observed with a conventional thermal imaging camera. 相似文献
2.
L. P. Babich 《Journal of Experimental and Theoretical Physics》2004,98(4):707-718
The collision operator of relativistic electrons with a cold gas of atomic particles is derived consistently taking into account elastic interactions, excitation of electron shells, and ionization. The creation of secondary electrons is described accurately. In the range of energies exceeding the binding energy of atomic electrons, the operator implicates only the angular scattering by nuclei and the ionization integral that automatically allows for scattering by atomic electrons. The collision operator used earlier for studying the kinetics of avalanches of relativistic runaway electrons is analyzed. A more exact operator derived in the present study is simpler in form and saves time in computer calculations. 相似文献
3.
Automorphisms of groups acting faithfully on rooted trees are studied. We find conditions under which every automorphism of such a group is induced by a conjugation from the full automorphism group of the rooted tree. These results are applied to known examples such as Grigorchuk groups, Gupta–Sidki group, etc. 相似文献
4.
5.
Sergio Albeverio Volodymyr Koshmanenko Mykola Pratsiovytyi Grygoriy Torbin 《Positivity》2006,10(1):39-49
We introduce the conflict interaction with two positions between a couple of image probability measures and consider the associated
dynamical system. We prove the existence of invariant limiting measures and find the criteria for these measures to be a pure
point, absolutely continuous, or singular cotinuous as well as to have any topological type and arbitary Hausdorff dimension. 相似文献
6.
N. S. Nametikin V. M. Vdovin E. D. Babich V. D. Oppengeim 《Chemistry of Heterocyclic Compounds》1966,1(3):305-309
Ammonolysis of silacyclobutanes {ie305-01} (R=Cl, CH3) gives silacyelobutane di- and polysilazanes. Reaction of the disilazane {ie305-02} with 1-chloro-1-methyl-1-silacyelobutane at 20–80° gives a trisilyl-substituted amine {ie305-03}. Trisilyl-substituted amines with one silacyclobutyl group, are obtained by reacting silacyclobutanes {ie305-04} (R=CH3, C6H5). with sodium or potassium silylamides prepared from hexamethyldisilazane. It is shown that it is possible to obtain silylamides by reacting disilazanes directly with potassium metal at 90–100°. 相似文献
7.
V. M. Babich 《Journal of Mathematical Sciences》1985,28(5):628-632
One considers the problem of the asymptotic behavior for K→+∞ of the solution of the Cauchy problem $$u_{tt} - u_{xx} + \kappa ^2 u = 0; u|_{t = 0} = \theta (x), u_t |_{t = 0} = 0 (t > 0 - fixed)$$ Hereθ(x) is the Heaviside function. In the neighborhood of the characteristics x=±t function u(x,t)?2 oscillates exceptionally fast (the wavelength is of order k?2). Near the t axis the asymptotics of u(x,t) contains the Fresnel integral. 相似文献
8.
Radiophysics and Quantum Electronics - 相似文献
9.
N. M. Muratova L. I. Martynenko V. I. Spitsyn V. A. Babich M. Yu. Kolleganov 《Russian Chemical Bulletin》1979,28(7):1337-1340
Conclusions Using high-resolution spectrography the authors have shown that in the system ethylenediaminedisuccinate-neodymium (III) chloride there are formed two forms of unprotonized monocomplexonates of the same composition but differing in the number of donor atoms of the ligand cordinated with the central neodymium ion. One of the forms of neodymium monoethylenediaminedisuccinate contains free donor groups and can therefore form polynuclear complexes with the aquo ions of neodymium introduced into the solution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1431–1435, July, 1979. 相似文献
10.
The first stage of the reaction of hexamethyldisilazane with 1-chloro-1-methyl-1-silacyclotmtane gives 1,3,3,3-tetramethyl-1,1-trimethylenedisilazane, and after that 1,3-dimethyl-1,3-bis(trimethylene)disilazane is formed. The latter reacts with 1-chloro-1-methyl-1-silacyclobutane to give tris[methyl(trimethylene)silyl] amine. From a large number of examples it is shown that transsilylation of disilazanes with chlorosilanes is a general reaction. 相似文献