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91.
O. S. Trushin 《Russian Microelectronics》2008,37(6):363-372
Atomic mechanisms of elastic-stress relaxation in heteroepitaxial structures are investigated by computer simulation. A 2D model of a heteroepitaxial structure with an empirical interatomic potential is considered. Advanced methods of saddle-point search in a multidimensional space are used to identify main mechanisms of structural change involving the formation of a structural imperfection, and to estimate energy characteristics of the processes. 相似文献
92.
A. A. Nechitaĭlov T. K. Zvonareva A. D. Remenyuk V. A. Tolmachev D. N. Goryachev O. S. El’tsina L. V. Belyakov O. M. Sreseli 《Semiconductors》2008,42(10):1249-1254
Catalytic properties of composite amorphous carbon-platinum layers produced by magnetron cosputtering have been studied. The layers were characterized by electron microscopy, IR spectroscopy, ellipsometry, gravimetry, and spectrophotometric chemical analysis. The catalytic activity of the layers was studied in an air-hydrogen fuel cell by measuring its load and power characteristics. 相似文献
93.
D. D. Avrov S. I. Dorozhkin Yu. M. Tairov A. Yu. Fadeev A. O. Lebedev 《Semiconductors》2008,42(13):1469-1474
The problem of the appearance of carbon inclusions in single-crystal silicon carbide ingots grown by the modified Lely method (the so-called graphitization of the ingot) is analyzed. It is shown that the process of graphitization of the ingot is not related to a deficit of silicon in the growth cell; in contrast, it is excess of silicon at the growth surface that inhibits the ingot growth rate and gives rise to intense corrosion of the graphite fittings. 相似文献
94.
We introduce functions for relative maximization in a general context: the beta and alpha applications. After a systematic study of different kinds of regularities, we investigate how to approximate certain values of these functions using periodic orbits. We also show that the differential of an alpha application determines the asymptotic behavior of the optimal trajectories. 相似文献
95.
O. A. Neucheva A. A. Evstrapov Yu. B. Samsonenko G. E. Cirlin 《Technical Physics Letters》2007,33(11):923-925
We have studied the reflectivity spectra of doped GaAs nanowhiskers (NWs) with various morphologies, which were grown by molecular-beam epitaxy. It is established that the character of the reflectivity spectra of NWs is determined by the shape of nanocrystals. NWs with droplike and pointlike vertices differently interact with electromagnetic radiation. Laser radiation produces a spectraly selective action on the NW array, which leads to a change in the NW height and induces “caking” of their vertices, thus modifying the reflectivity of the sample. This phenomenon can be used for the creation of local microstructures with preset characteristics in large NW arrays. 相似文献
96.
F. Barlat S. Panchanadeeswaran O. Richmond 《Metallurgical and Materials Transactions A》1991,22(7):1525-1534
A simple model of flange behavior during cup drawing was used to predict the earing profile of deep-drawn cups. The relationship
between yield surface shape and earing tendency was established, with plane stress yielding corresponding to no hold-down
pressure on the flange and plane strain corresponding to no thickening. Using the Schmid law, the earing model was applied
to the case of a single crystal in cube position and compared to Tucker’s well-known results.[6] For the plane strain case, good agreement was obtained with the experiment; but for plane stress, the predicted profile did
not agree with the experimental one. Using the Taylor/ Bishop and Hill (TBH) theory[8,9] and measured crystallite orientation distribution functions (CODF), the model was applied to the case of high-purity aluminum
sheet with various cold-rolling reductions (35, 60, 80, and 90 pct). The major experimental trends were again correctly predicted
by the plane strain case. 相似文献
97.
This paper examines the current status and methodologies of study of material and system reliability in Microelectromechanical Systems (MEMS). This includes: a review of the current literature in the area of MEMS regarding failure analysis experimental investigations; testing methods and philosophies for material characterization and possible mechanistic analytical solutions for estimating material properties. The paper proposes a reliability framework that encompasses all the available information. This statistical platform will enable the MEMS design engineer to distill all the available information in the literature into a stand-alone semi-empirical material reliability model, and a holistic system-level model for a complete system. 相似文献
98.
Birnessites containing Na, K or Li in the interlayer have been prepared by oxidation of Mn(II) cations with H2O2 in a basic medium with different alkaline cation/Mn molar ratios. The solids prepared have been characterised by elemental chemical analysis, powder X-ray diffraction, thermal analyses (differential thermal analysis and thermogravimetric analysis), FT-IR spectroscopy and surface texture assessment by adsorption of N2 at –196°C. Crystalline birnessites are obtained for A/Mn ratios (A = K, Li) larger than 3.4, but MnO(OH) has been also identificed when such a ratio is smaller than 3.4. Ion exchange is topotactic, but is not complete for exchanging Na, K, or Mg for pre-existing Li. The solids are stable up to 400°C, and formation of spinels and solids with tunnel structures is observed at this temperature. Li-containing birnessites are transformed to LiMn2O4 spinel at 400°C, and co-crystallization of bixbyte (Mn2O3) is observed at higher temperatures. Bixbyte and cryptomelane are formed at 500°C for the K-containing birnessites. 相似文献
99.
Y Stern M Aronson T Shpitzer O Nativ O Medalia K Segal R Feinmesser 《Canadian Metallurgical Quarterly》1995,121(9):1003-1005
OBJECTIVE: To assess the role of DNA ploidy as a predictor of radioresistance in T1 glottic carcinoma. DESIGN: Case-control study. Flow cytometric DNA ploidy measurements were performed on formalin-fixed paraffin-embedded tumor specimens from 15 patients with T1 glottic laryngeal carcinomas in whom radiotherapy had failed and from a matched group of 15 patients in whom an identical radiotherapy regimen was curative. Analysis of DNA content was performed blind to outcome of treatment. SETTING: Academic tertiary referral medical center. PARTICIPANTS: Thirty patients with clinically staged T1, N0, M0 glottic carcinoma. INTERVENTION: All patients received radiation to the larynx through opposed lateral ports at a total dose of 64 to 70 Gy. RESULTS: Ten diploid and five aneuploid histograms were found in the resistant group, and six diploid and nine aneuploid histograms were found in the radiosensitive group. This difference was not statistically significant. A trend toward a higher relapse rate after radiotherapy (62.5%) among patients with diploid tumor compared with those with aneuploid tumor (35.7%) was noted. CONCLUSIONS: DNA ploidy did not predict response to radiotherapy in patients with T1 glottic cancer, probably because of the small number of patients. A trend toward lower risk of local recurrence after radiotherapy in aneuploid tumors was noted. A larger prospective study is needed to assess the value of DNA ploidy in the treatment of early laryngeal cancer. 相似文献
100.