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991.
It is shown that, at thermodynamic equilibrium, the release of charge carriers from the localized states of bistable amphoteric centers into quasi-free states depends on the degree of compensation. This brings about different functional dependences of the concentration of free charge carriers on temperature. It is found that, in uncompensated semiconductors, the concentration of free charge carriers follows the same dependence in the case of bistable amphoteric centers and bistable amphoteric U ? centers, although the distributions of charge carriers over the charge states and configurations are different for these types of centers. The results can be used for interpreting various experimental data insufficiently explained in the context of the traditional approach. 相似文献
992.
A numerical analysis of an optical chaotic transmission system, based on the synchronization of two chaotic lasers, in a master-slave closed loop configuration is presented. At the transmitter, the master chaotic wave is superposed on the information message; at the receiver, the message is recovered by subtracting the synchronized slave chaotic wave from the received signal. The performances are analyzed in terms of the Q-factor, considering two different message modulation formats: the nonreturn-to-zero and the Manchester coding. The Manchester coding shows enhanced performances due to the shift of the signal spectrum to higher frequencies. 相似文献
993.
In this work, we have created a new type of structure, the nanopore active layer, for achieving quantization of carrier states in a semiconductor. The nanopore structure consists of a periodic two-dimensional array of localized energy barriers perturbing an otherwise conventional quantum well. This perturbation leads to the formation of intraband forbidden energy gaps which are observed experimentally. 相似文献
994.
M. I. Makoviychuk 《Russian Microelectronics》2008,37(4):226-237
The solution proposed relates to flicker-noise gas sensors under development, which differ from conventional chemical sensors in offering exceptional selectivity for the analysis of a gaseous environment. The classification and analytical justification are given of low-frequency-noise spectroscopy techniques and measures that are proposed for investigation of disordered semiconductors. The feasibility is shown of patterning processes for flicker-noise gas sensors. Some methods are proposed for these processes and for measurement procedures of gaseous-environment monitoring. 相似文献
995.
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
996.
Vjacheslav V. Zuev 《Journal of Polymer Research》2008,15(5):351-356
Functionalized polyanilines containing biphenyl, terphenyl, carbazole, anthracene, and 4-n-hexylphenyl moieties were synthesized though the reaction of polyaniline in emeraldine base form with sodium salt of corresponding
vinylketoaromatics with quantitative yields. Polymers were characterized with Fourier transform infrared spectroscopy, proton
nuclear magnetic resonance spectroscopy, and thermogravimetry. The emission characteristics of these polymers in N-methyl-2-pyrrolidone solution were examined. The functionalized polyanilines exhibited an intense green emission. 相似文献
997.
We propose two new antidiffusive schemes for advection (or linear transport), one of them being a mixture of Roe’s Super-Bee
scheme and of the “Ultra-Bee” scheme. We show how to apply these schemes to treat time-dependent first order Hamilton–Jacobi–Bellman
equations with discontinuous initial data, possibly infinitely-valued. Numerical tests are proposed, in one and two space
dimensions, in order to validate the methods
AMS subject classifications. Primary 65M12, Secondary 58J47 相似文献
998.
S. Genovés J.V. Gil P. Manzanares J.L. Aleixandre S. Vallés 《Journal of food science》2003,68(6):2096-2100
ABSTRACT: A recombinant Saccharomyces cerevisiae wine yeast strain expressing the Candida molischiana bgln gene encoding a β-glucosidase (BGLN) has been used to produce this enzyme. Shaking rate, pH, and aeration rate conditions have been optimized to obtain maximum activity to facilitate enzyme purification. The ability of the heterologous enzyme to efficiently release terpenols and alcohols from a Muscat wine glycoside extract and also directly from wine has been demonstrated. Terpenol glycoside content decreased by 50% after 1 mo of wine storage in agreement with results reported for the β-glucosidase produced by C. molischiana. 相似文献
999.
P. M. Solozhenkin E. A. Deliyanni V. N. Bakoyannakis A. I. Zouboulis K. A. Matis 《Journal of Mining Science》2003,39(3):287-296
The original method is developed for producing the new inorganic sorption material of akaganeite bgr-FeO(OH). The material in question is characterized relative to arsenic contained in aqua. The possibility is established for removing arsenate ions from water by contemporary physicochemical methods. 相似文献
1000.
The results of computer simulations demonstrate the possibility of light energy transmission through band gaps of a one-dimensional photonic crystal with fluctuating lengths of individual layers. In the case of weak (±5%) fluctuations, the light pulse energy partly penetrates in depth a photonic crystal. If fluctuations of the layer length are strong (±20%), the light pulse energy can be partly transmitted through the crystal. 相似文献