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排序方式: 共有381条查询结果,搜索用时 15 毫秒
1.
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
2.
V. V. Afrosimov E. K. Gol’man R. N. Il’in M. N. Panov D. A. Plotkin S. V. Razumov V. I. Sakharov I. T. Serenkov A. V. Tumarkin 《Technical Physics Letters》1998,24(1):41-42
Superconducting YBa2Cu3O7−x
films were prepared by magnetron sputtering on Al2O3 single crystals with a CeO2 sublayer. Scattering of moderate-energy ions and x-ray diffraction were used to show that the films exhibit good single-crystal
properties over the entire thickness up to 2.6 μm. The hypothesis is advanced that the indentations formed by the growth of films above “extraneous” phase grains may act
as defect sinks.
Pis’ma Zh. Tekh. Fiz. 24, 91–95 (January 12, 1998) 相似文献
3.
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
4.
Pavel A. Sakharov Egor A. Smolin Dmitry N. Lyabin Sultan C. Agalarov 《International journal of molecular sciences》2021,22(7)
The methylation of adenosine in the N6 position (m6A) is a widely used modification of eukaryotic mRNAs. Its importance for the regulation of mRNA translation was put forward recently, essentially due to the ability of methylated mRNA to be translated in conditions of inhibited cap-dependent translation initiation, e.g., under stress. However, the peculiarities of translation initiation on m6A-modified mRNAs are not fully known. In this study, we used toeprinting and translation in a cell-free system to confirm that m6A-modified mRNAs can be translated in conditions of suppressed cap-dependent translation. We show for the first time that m6A-modified mRNAs display not only decreased elongation, but also a lower efficiency of translation initiation. Additionally, we report relative resistance of m6A-mRNA translation initiation in the absence of ATP and inhibited eIF4A activity. Our novel findings indicate that the scanning of m6A-modified leader sequences is performed by a noncanonical mechanism. 相似文献
5.
The new, deformable alloy 1441 (system Al - Cu - Mg - Li - Zr) has a lower density (by 6.8%) and a higher elasticity modulus (by 12%) than alloy 1163 (3.8 - 4.5% Cu, 1.2 - 1.6% Mg, 0.4 - 0.8% Mn, and Al), and a longer service life for comparable strength properties. Investigation of the properties and structure of alloy 1441 after deformation is of interest.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 20 – 22, February, 1995. 相似文献
6.
S. V. Bobashev N. P. Mende V. A. Sakharov D. M. Van Wie 《Technical Physics Letters》2004,30(8):635-637
Magnetohydrodynamic impact on a cold supersonic nitrogen flow with external magnetic field was realized in an experimental
complex based on the Big Shock Tube at the Ioffe Physicotechnical Institute. A pulsed supersonic flow with a Mach number of
M=4 and steady phase duration of about 1.5 ms was created by expansion of the shock-heated nitrogen flow from a supersonic
nozzle. The gas was ionized by pulsed discharge between two electrodes mounted on the nozzle wall so that an electric current
of up to ∼500 A passed in the direction perpendicular to the gas flow at the dielectric wall. External magnetic field ∼0.3
T was perpendicular to the gas flow and the current direction. It is established that the magnetic field significantly modifies
the shock wave structure in the flow. 相似文献
7.
8.
9.
V. N. Chuvil’deev A. V. Nokhrin I. M. Makarov Yu. G. Lopatin N. V. Sakharov N. V. Melekhin A. V. Piskunov E. S. Smirnova V. I. Kopylov 《Russian Metallurgy (Metally)》2012,2012(5):415-427
The structure and the electrical and mechanical properties of Al-Mg-0.22 wt % Sc-0.15 wt % Zr alloys with various magnesium contents (0, 1.5, 4.5 wt %) are experimentally studied during the decomposition of the solid solution of scandium and zirconium in the states after solidification from a melt (cast ingots) and after subsequent multicycle equal-channel angular pressing (microcrystalline structure). The dependences of electrical resistivity ??, microhardness HV, macroelasticity limit ??0, and yield strength ??y on the annealing temperature and time are analyzed. 相似文献
10.
W. V. Lundin E. E. Zavarin M. M. Rozhavskaya A. E. Nikolaev V. Sakharov S. I. Troshkov M. A. Sinitsyn D. V. Davydov M. M. Kulagina P. N. Brunkov A. F. Tsatsulnikov 《Technical Physics Letters》2012,38(3):265-267
Epitaxial gallium nitride (GaN) structures have been manufactured by the lateral overgrowth technology, whereby GaN epilayers are grown in stripe windows on a partly masked initial GaN layer. It is established that in addition to the traditional orientation of stripes across the c axis, the process is also possible for the stripes oriented at 45° relative to this axis. In this case, two lateral overgrowth processes in mutually perpendicular directions can be performed, which would significantly reduce the relative area of imperfect material formed over windows in the mask. 相似文献