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871.
Eric P. Kvam Ph.D. Srikanth B. Samavedam B.Tech. 《JOM Journal of the Minerals, Metals and Materials Society》1994,46(3):47-51
The Ge-Si on Si epilayer system, besides being an interesting technological system in its own right, is a superb model for strained-layer studies. The point defect and symmetry defect structures associated with compound semiconductors can be avoided, allowing a focus on the mechanics of the system. Dislocation sources, glide behavior, and performance effects have been examined for strained-layer systems. Surprises have appeared along the way, but these materials are now becoming characterized well enough for industrial device applications. 相似文献
872.
S. I. Glinchak Yu. A. Egorov R. R. Aliev E. D. Radchenko B. K. Nefedov N. A. Grigor'ev 《Chemistry and Technology of Fuels and Oils》1992,28(3):175-177
Translated from Khimiya i Tekhonologiy Topliv i Masel, No. 3, pp. 33–34, March, 1992. 相似文献
873.
874.
A 90° microstrip bend is characterized using a time-frequency method based on the finite-difference-time-domain (FDTD) method. Time evolution of the currents generated by FDTD are Fourier transformed to lead to S-parameters and the radiated powers characteristic of the microstrip bend. The method for calculating both radiation and surface wave losses is developed for microstrip structures. The results of the 90° microstrip bend are compared with the results of the mitered microstrip bend 相似文献
875.
876.
Low-temperature interface reaction in aluminium-silicon carbide particulate composites produced by mechanical alloying 总被引:1,自引:0,他引:1
An experimental investigation has been carried out on the reaction that takes place between 3 and 20 μm SiC particles and
the aluminium alloy 1050 matrix of composite materials prepared by a mechanical alloying process. The work is different from
that undertaken by other researchers in that the SiC-Al interface reaction has been studied in the temperature range 853–933
K, i.e., with the matrix initially in the solid state. Differential thermal analysis, X-ray diffraction and scanning electron
microscopy all show that the SiC-Al reaction initiates in the solid state at temperatures as low as 883 K. The reaction produces
Al4C3 and Si, the latter entering into solid solution in the aluminium matrix. At temperatures exceeding 903 K, the reaction
produces a liquid phase and at this stage the speed of the interface reaction increases significantly. The results are discussed
in terms of Al-Si-C metastable equilibrium and the kinetics of the reaction.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
877.
Using time-of-flight technique between 100 K and 700 K a nearly constant IC modulation parameter is found. It depends only weakly on crystal composition. The intensity of the first-and second-order satellites decreases with temperature and at 700 K it is nearly disappeared. These facts are discussed with a view to the anti-phase domain model. 相似文献
878.
Adaptive arithmetic coders sometimes exhibit nonstationary symbol probabilities when coding digital halftone images with neighborhood-template models. If these nonstationary probabilities vary nonrandomly, the variations can be tracked robustly when each context derived from the coding model is expanded by conditioning on previously coded values for that model context. 相似文献
879.
The authors present an adaptive space-time reduced-length minimum mean-squared error (MMSE) receiver to suppress co-channel interference in the near-far environment for an asynchronous direct-sequence code-division multiple-access (DS/CDMA) system. Simulation results show that better bit-error rate and faster and more stable convergence are achieved over the existing full- and reduced-length MMSE receivers 相似文献
880.
K.-H. Zum Gahr R. Telle B. Zimmerlin S.-H. Park 《Materialwissenschaft und Werkstofftechnik》1992,23(9):329-338
Influence of grain size on mechanical properties and dry oscillating sliding wear of Al2O3-ceramics Specimens with average grain sizes varying between about 0.8 μm and 12 μm were produced by cold isostatic pressing of high purity Al2O3-powder followed by sintering between 1300°C and 1700°C. Hardness, Young's modulus, bending strength and fracture toughness were measured as a function of average grain sizes. Tribological tests were carried out on the different microstructures at normal laboratory air and room temperature by using a ring-on-block tribometer. Experimental results showed the dependence of mechanical properties on grain size, hardness and bending strength obeying a Hall-Petch type relation, approximately. Coefficient of friction was relatively independent of grain size under the test conditions used. However, wear intensity increased substantially if a critical grain size was surpassed. This was due to a change in mechanisms of material removal which was confirmed by scanning electron microscopical studies of the worn surfaces. 相似文献