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81.
Nonalloyed ohmic contacts for high-electron-mobility transistors based on AlGaN/GaN heterostructures
A. Yu. Pavlov V. Yu. Pavlov D. N. Slapovskiy S. S. Arutyunyan Yu. V. Fedorov P. P. Mal’tsev 《Russian Microelectronics》2017,46(5):316-322
A microwave field-effect transistor with nonalloyed ohmic contacts is fabricated using the technique of regrowing a heavily doped region under the contact metallization by molecular beam epitaxy through a preliminarily formed dielectric mask. The fabricated field-effect transistor with a gate length of 0.18 µm and a total width of 100 µm has a current–amplification cutoff frequency of 66 GHz and ohmic contact resistivity of 0.15-0.18 Ω mm. 相似文献
82.
N. D. Goletskii B. Ya. Zilberman Yu. S. Fedorov A. S. Kudinov A. A. Timoshuk L. V. Sytnik E. A. Puzikov S. A. Rodionov A. P. Krinitsyn V. I. Ryazantsev D. V. Ryabkov 《Radiochemistry》2014,56(5):501-514
Possible ways of Tc and Np localization within the framework of the first extraction cycle of the Purex process are considered. Experimental data are presented on Tc localization in the high-level raffinate as applied to the RT-1 flowsheet, in the zirconium-tritium strip, and in the Pu-Np product or in the scrub from the unit of the barrier reductive scrubbing of the uranium solvent product as applied to six-unit extraction scheme in the design of the Experimental and Demonstration Center. For the latter case, the possibility of Np localization before and after Pu stripping was also examined. 相似文献
83.
For safety issues related to the storage of gases (e.g. hydrogen) under high pressure, it is necessary to determine how the gas is released in the case of failure. In particular, there exist limited quantitative information on the near-field properties of gas jets, which are important for establishing proper decay laws in the far-field. Simulations of the near-field of highly underexpanded (high pressure) gas jets have been performed using Finite-Volume solver of the CAST3M code and validated using several sources available in the literature. The numerical model solves the 3D Compressible Multi-Component Navier–Stokes equations directly without relying on the compressibility-corrected turbulence models. It provides sufficiently fair mean predictions both in the case of one-component air–air and two-component helium-air releases. Possible initial conditions for the far-field simulations are suggested in terms of distance from the source, as well as the turbulence characteristics and gas-dynamic parameters at this location. In addition, these results are used to evaluate several notional nozzle concepts in order to determine the one physically consistent. 相似文献
84.
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86.
Alexey Komkov Rostislav Kamkin 《JOM Journal of the Minerals, Metals and Materials Society》2011,63(1):73-76
A thermodynamic mathematical model, describing behavior of Pb, Zn, and As during reducing slag cleaning in the Vanyukov furnace
has been developed. Using a developed model, the influence of different factors, such as temperature, oxygen partial pressure,
the ratio of the formed phases on the behavior of impurities, was analyzed. It was found that arsenic can significantly move
to the bottom phase, and zinc can be significantly vaporized under conditions in the Vanyukov furnace. 相似文献
87.
Effect of silicon content in steel and oxidation temperature on scale growth and morphology 总被引:1,自引:0,他引:1
Amine Alaoui Mouayd Alexey Koltsov Eliane Sutter Bernard Tribollet 《Materials Chemistry and Physics》2014
The effect of high silicon content in steel, 1.6 wt.%Si and 3.2 wt.%Si, and high oxidation temperatures (850–1200 °C) on scale growth rate and morphology were investigated. The steels were oxidized in a 15% humid air with short isothermal oxidation times (15 min). The scale growth rate of the non-alloyed steel follows a parabolic law with time; it is an iron diffusion controlled oxidation. The presence of silicon delays scale growth by forming a silica SiO2 barrier layer at the scale/metal interface, this effect is more important for the steel containing 3.2 wt.%Si and induces a discontinuous scale. Silicon oxides are concentrated at the scale/metal interface; their morphology depends on the oxidation temperature. For temperatures lower than 950 °C, silica is formed. Between 950 °C and 1150 °C, fayalite (Fe2SiO4) grains appear in the wüstite matrix close to the scale/metal interface. For temperatures higher than 1177 °C, a fayalite–wüstite eutectic is formed; this molten phase favours iron diffusion leading to high scale growth. After cooling, a continuous fayalite layer with small wüstite grains is obtained at the scale/steel interface. 相似文献
88.
89.
Alexey A. Roenko Vladimir V. Lukin Igor Djurović Xu Zhengguang 《Signal, Image and Video Processing》2009,3(2):157-170
A novel adaptive clipping technique for filtering a constant amplitude frequency modulated (FM) signal embedded in non-Gaussian
noise is proposed. It is based on the analysis and processing of the estimate of probability density function of a FM signal
realization. As a result, modifications of two robust estimators of FM signal amplitude are proposed. It is shown that these
estimators can be used for Gaussian and non-Gaussian heavy-tail environments. The proposed clipping technique can exploit
one or another obtained robust estimate of the signal amplitude for adaptive setting a threshold. Analysis of signal estimate
accuracy for different noise environments is carried out. Comparative analysis of the obtained methods and known approaches
based on scanning window nonlinear filtering and optimal robust L-DFT form is performed. It is demonstrated that the usage
of clipping-based technique leads to the considerable improvement of the FM signal filtering efficiency in comparison to the
aforementioned known approaches for different noise environments and a wide range of input SNR values. 相似文献
90.
Aleksi Eskelinen Alexey Zakharov Sirkka‐Liisa Jämsä‐Jounela Jonathan Hearle 《American Institute of Chemical Engineers》2015,61(11):3683-3698
A dynamic model of a multiple hearth kaolin calciner has been developed and is presented in this article. This model describes the physical‐chemical phenomena taking place in the six furnace parts: the solid phase, gas phase, walls, cooling air, rabble arms, and the central shaft. The solid phase movement, in particular, is described by a novel mixing model. The mixing model divides the solid bed in a hearth into volumes and the distribution of their contents, after one full central shaft rotation, is identified by the pilot experiments. First, the model is validated by the industrial data, and then the dynamics of the multiple hearth furnace is studied by introducing step changes to the three manipulated variables: the feed rate, and the gas, and air flows supplied. The responses of the gas phase temperature and solid bed component profiles are analysed and the results are discussed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3683–3698, 2015 相似文献