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1.
Phonon spectra and state densities of MeF2 (Me = Ca, Sr, Cd, Ba, or Pb) crystals are calculated in the basis of sublattice state vectors using the Born–Mayer model. The phonon spectra and the sublattice state densities are calculated in the field of the second frozen sublattice. It is demonstrated that optical crystal branches are mainly due to oscillations of fluorine ions; moreover, the topology of optical branches in the spectrum and the crystal state densities are close to the topology of the spectra and state densities of the fluorine sublattice in the frozen metal sublattice. Exception is CaF2 whose ion and cation masses are close in values. 相似文献
2.
V. A. Donchenko A. I. Yakimov A. A. Zemlyanov V. V. Kirienko 《Russian Physics Journal》2010,53(5):504-507
Results of investigations into the time characteristics of photosensitive layers based on Ge/Si nanoheterostructures excited by femtosecond laser pulses with a wavelength of 1.55 μm are given. It is demonstrated that the leading front duration of the photoresponse pulse for the examined specimens excited by laser pulses of 120 fs duration does not exceed 30–40 пs. 相似文献
3.
N. P. Krut'ko L. V. Dikhtievskaya A. D. Markin V. V. Shevchuk A. S. Gorbachev M. M. Varava V. M. Kirienko 《Russian Journal of Applied Chemistry》2005,78(8):1213-1217
The surface activity of higher aliphatic amines and their salts at the interface between their solutions and air, oil, and KCl grains and their influence on the strength characteristics, moisture absorption, and caking of the grains were studied. 相似文献
4.
A. I. Yakimov A. V. Dvurechenskii V. V. Kirienko A. I. Nikiforov 《Physics of the Solid State》2005,47(1):34-37
Photodetectors based on Ge/Si multilayer heterostructures with germanium quantum dots are fabricated for use in fiber-optic communication lines operating in the wavelength range 1.30–1.55 μm. These photodetectors can be embedded in an array of photonic circuit elements on a single silicon chip. The sheet density of germanium quantum dots falls in the range from 0.3 × 1012 to 1.0 × 1012 cm?2, and their lateral size is approximately equal to 10 nm. The heterostructures are grown by molecular-beam epitaxy. For a reverse bias of 1 V, the dark current density reaches 2 × 10?5 A/cm2. This value is the lowest in the data on dark current densities available in the literature for Ge/Si photodetectors at room temperature. The quantum efficiency of photodiodes and phototransistors subjected to illumination from the side of the plane of the p-n junctions is found to be 3% at a wavelength of 1.3 μm. It is demonstrated that the maximum quantum efficiency is achieved for edge-illuminated waveguide structures and can be as high as 21 and 16% at wavelengths of 1.3 and 1.5 μm, respectively. 相似文献
5.
We have established that introducing a promoter (Pd) and modifying additives (La2O3, CeO2) into the composition of a Co3O4/cordierite catalyst leads to an increase in its activity and selectivity during reduction of oxygen by hydrogen in the presence
of nitrogen(II) oxide. 相似文献
6.
The effect of CeO2 on the properties of the Pd/Co3O4-CeO2/cordierite catalyst is a function of the method of its preparation. The catalyst obtained by the simultaneous deposition
of cerium oxide and cobalt oxide showed high activity in the oxidation of CO (CO + O2, CO + NO) and extensive oxidation of hexane (C6H14 + O2). This behavior is due to the increased mobility of surface oxygen and increased dispersion of the catalyst components. 相似文献
7.
N. F. Lukina L. A. Dement’eva A. P. Petrova T. A. Kirienko L. V. Chursova 《Polymer Science Series D》2016,9(4):387-391
The main physical, mechanical, and rheological properties of VSK-14-2m and VSK-14-3 moltentype epoxy adhesive binders are described. The optimal temperature range for the processing of these binders for the synthesis of high-quality adhesive prepregs reinforced with glass and coal fillers is shown. 相似文献
8.
Yakimov A. I. Bloshkin A. A. Kirienko V. V. Dvurechenskii A. V. Utkin D. E. 《JETP Letters》2021,113(8):498-503
JETP Letters - It has been found that the introduction of layers of Ge/Si quantum dots in a two-dimensional photonic crystal leads to a strong (up to a factor of 5) increase in the photocurrent in... 相似文献
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10.
The photoconductive gain, hole photocurrent spectra in the mid-infrared range, and band-to-band photoluminescence spectra in arrays of Ge/Si quantum dots with different elemental compositions of the heterointerface are measured. The diffusive mixing of the materials of the matrix and the dots is controlled by varying the temperature at which the Ge layers are overgrown with Si. It is found that the formation of abrupt heterointerfaces leads to the enhancement of the hole photocurrent and quenching of photoluminescence. The results are explained by an increase in the lifetime of nonequilibrium holes owing to the suppression of their capture into the bound states of quantum dots. 相似文献