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排序方式: 共有143条查询结果,搜索用时 15 毫秒
1.
Yu. B. Vasil’ev S. D. Suchalkin S. V. Ivanov B. Ya. Mel’tser A. F. Tsatsul’nikov P. V. Neklyudov P. S. Kop’ev 《Semiconductors》1997,31(10):1071-1073
Cyclotron resonance is measured in solitary type-II InAs-AlGaSb quantum wells grown by molecular-beam epitaxy under various
growth conditions. Quantum oscillations observed in the cyclotron resonance spectra in InAs-GaSb samples are attributed to
scattering by a short-range potential due to roughness of the heterointerface. A new method based on measurement of the cyclotron
resonance spectra is proposed for assessing the quality of the heterointerface.
Fiz. Tekh. Poluprovodn. 31, 1246–1248 (October 1997) 相似文献
2.
V. N. Jmerik A. M. Mizerov T. V. Shubina A. V. Sakharov A. A. Sitnikova P. S. Kop’ev S. V. Ivanov E. V. Lutsenko A. V. Danilchyk N. V. Rzheutskii G. P. Yablonskii 《Semiconductors》2008,42(12):1420-1426
Features of plasma-assisted molecular-beam epitaxy of AlGaN compounds at relatively low temperatures of the substrate (no higher than 740°C) and various stoichiometric conditions for growth of the nitrogen- and metal-enriched layers are studied. Discrete submonolayer epitaxy for formation of quantum wells and n-type blocking layers without varying the fluxes of components was used for the first time in the case of molecular- beam epitaxy with plasma activation of nitrogen for the nanostructures with the Al x Ga1 ? x N/Al y Ga1 ? y N quantum wells. Structural and optical properties of the Al x Ga1 ? x N layers in the entire range of compositions (x = 0–1) and nanostructures based on these layers are studied; these studies indicate that there is photoluminescence at room temperature with minimum wavelength of 230 nm. Based on the analysis of the photoluminescence spectra for bulk layers and nanoheterostructures and their temperature dependences, it is concluded that there are localized states in quantum wells. Using the metal-enriched layers grown on the c-Al2O3 substrates, heterostructures for light-emitting diodes with Al x Ga1 ? x N/Al y Ga1 ? y N quantum wells (x = 0.4–0.5, y = x + 0.15) were obtained and demonstrated electroluminescence in the ultraviolet region of the spectrum at the wavelength of 320 nm. 相似文献
3.
M. M. Zverev N. A. Gamov D. V. Peregoudov V. B. Studionov E. V. Zdanova I. V. Sedova S. V. Gronin S. V. Sorokin S. V. Ivanov P. S. Kop’ev 《Semiconductors》2008,42(12):1440-1444
Emission characteristics of an electron-beam-pumped Cd(Zn)Se/ZnMgSSe semiconductor laser are studied. The laser’s active region consists of a set of ten equidistant ZnSe quantum wells containing fractional-monolayer CdSe quantum-dot inserts and a waveguide formed by a short-period superlattice with the net thickness of ~0.65 μm. Lasing occurs at room temperature at a wavelength of 542 nm. Pulsed power as high as 12 W per cavity face and an unprecedentedly high efficiency of ~8.5% are attained for the electron-beam energy of 23 keV. 相似文献
4.
Yu. M. Shernyakov A. Yu. Egorov B. V. Volovik A. E. Zhukov A. R. Kovsh A. V. Lunev N. N. Ledentsov M. V. Maksimov A. V. Sakharov V. M. Ustinov Zhen Zhao P. S. Kop’ev Zh. I. Alferov D. Bimberg 《Technical Physics Letters》1998,24(5):351-353
Continuous-wave lasing has been demonstrated in a vertically coupled quantum-dot laser with a high output power (1.5 W) at
room temperature. It was shown that anisotropy of the quantum dot profile leads to anisotropy of the laser operating characteristics.
Pis’ma Zh. Tekh. Fiz. 24, 50–55 (May 12, 1998) 相似文献
5.
V. I. Ignatov A. V. Shutikov Yu. A. Ryzhkov Yu. V. Kop’ev S. B. Ryzhov V. Ya. Berkovich Yu. M. Semchenkov R. Z. Aminov V. A. Khrustalev 《Thermal Engineering》2009,56(11):963-966
Safe operation of the Balakovo nuclear power station’s Unit 2 built around a VVER-1000 reactor at a thermal power output of
3120 MW with meeting of the safety criteria and compliance with the requirements of existing regulatory documents is substantiated.
Results from measurements of process parameters at a power output equal to 104% of its nominal value are presented. 相似文献
6.
V. V. Mamutin V. N. Zhmerik T. V. Shubina A. A. Toropov A. V. Lebedev V. A. Vekshin S. V. Ivanov P. S. Kop’ev 《Technical Physics Letters》1998,24(6):467-469
It is shown that GaN films can be grown by molecular-beam epitaxy with plasma activation of the nitrogen by a magnetron rf
discharge in a specially constructed coaxial source with capacitive coupling. A growth rate of ∼0.1 μm/h is obtained on GaAs and sapphire substrates, and ways are found for optimizing the design of the plasma source in order
to increase the growth rate. The electrophysical and luminescence properties of undoped epitaxial films are investigated at
temperatures ranging all the way to room temperature.
Pis’ma Zh. Tekh. Fiz. 24, 30–35 (June 26, 1998) 相似文献
7.
Applied 2 independent probabilities of electric shock presentation to 12 naive male rhesus monkeys (Macaca mulatta) as the independent variables defining schedules of aversive control: (a) the probability that a fixed signal period would end with a shock if a specified response were made and (b) the probability that the fixed signal period would end with shock if a specified response were not made. Systematic changes in the probability values generated several familiar schedules of aversive control, as well as several intermittent procedures. Response rate tended to rise during the signal period when the probability values were set so that not responding was more likely to produce a shock than responding; response rate tended to fall during the signal period when the probabilities were set so that responding was more likely to produce shock than not responding. Response patterning in time was also evident during the interval between signals when no consequences were programmed. These characteristics of response patterning reflected the changes in the 2 independent probability variables in ways that simple measures of response rate and shock rate alone did not. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
M. M. Zverev N. A. Gamov E. V. Zhdanova D. V. Peregudov V. B. Studenov S. V. Ivanov I. V. Sedova S. V. Sorokin S. V. Gronin P. S. Kop’ev 《Technical Physics Letters》2007,33(12):1032-1034
We have studied the output characteristics of pulsed electron-beam-pumped green lasers based on ZnSe-containing quantum-sized structures with thin (20 nm thick) external ZnMgSSe confinement layers. Room-temperature lasing has been observed for electron beam energies above 3.7 keV. At a beam energy of 8–9 keV, the minimum threshold beam current density was 0.4–0.5 A/cm2. The maximum laser output pulse energy was 2 W at a pumping electron beam energy of ~5 kW. 相似文献
9.
G. M. Batanov N. K. Berezhetskaya V. A. Kop’ev I. A. Kossyi A. N. Magunov 《High Temperature》2008,46(1):124-130
The temperature is determined in pulsed microwave discharges in powder mixtures at atmospheric pressure. The effect of microwave radiation of gyrotron (wavelength of 4 mm, power up to 200 kW, pulse duration of 1 to 10 ms) on a finely divided medium causes the emergence of plasma in a gas medium between solid particles; the thresholds (with respect to power) of generation of plasma in powder mixtures are hundreds of times lower than those in gas. The method of determining the discharge temperature consists in recording the radiation in a wide spectral range (200 to 850 nm) and comparing the obtained spectrum with the Planck spectrum in the Wien region. In the case of similarity of two spectra, the discharge temperature is determined as a parameter of the spectrum under observation. In so doing, no data on the emissivity of discharge are required for determining the temperature. It is demonstrated that microwave-discharge plasma in powders is characterized by a temperature of 2000–3000 K. 相似文献
10.
Aluminum control of phosphorus sorption by lake sediments 总被引:9,自引:0,他引:9
Kopácek J Borovec J Hejzlar J Ulrich KU Norton SA Amirbahman A 《Environmental science & technology》2005,39(22):8784-8789
Release of reactive (phosphate-like) phosphorus (P) from freshwater sediments represents a significant internal P source for many lakes. Hypolimnetic P release occurs under reducing conditions that cause reductive dissolution of ferric hydroxide [Fe(OH)3]. This hypolimnetic P release may be naturally low or artificially reduced by sediment with naturally high or artificially elevated concentrations of aluminum hydroxide [Al(OH)3]. We presentfield and laboratory data for a common extraction analysis of sediments from 43 lakes differing in trophic status, pH regime, climate, and P loading. The results indicate that a simple sequential extraction of sediment may be a useful predictor of sediment's ability to release P. Sequential extractions of sediment P, Al, and Fe by water (H2O), bicarbonate-dithionite (BD), and NaOH (at 25 degrees C) showed that negligible amounts of P would be released from lake sediments during hypolimnetic anoxia if either (1) the molar Al(NaOH-25):Fe(BD) ratio is > 3 or (2) the molar Al(NaOH-25):P(H2O+BD) ratio is > 25. These ratios can be used as operational targets for estimation of sediment P release potential and Al dosing of P-rich sediment to prevent hypolimnetic P release under anoxic conditions. 相似文献