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951.
Xiangdong Xu Hockleong Kweh Zhengcao Zhang Zhihong Liu Wei Zhou Wei Zhang Peixin Qian 《Applied Surface Science》2006,252(20):7594-7598
Large-scale preparation of thin strain-relaxed SiGe is achieved by combining ion implantation and ultrahigh vacuum chemical vapor deposition. The resulting materials were analyzed by double crystal X-ray diffraction, micro-Raman spectroscopy, and tapping mode atomic force microscope. Results revealed that 100-nm-thick Si0.7Ge0.3 layers with the diameter of 125 mm and full strain relaxation are successfully prepared by pre-modifying the Si substrates using 50 keV Ar+ ions. The strain relaxation is also disclosed to change with both ion species and energy. However, post-modification of SiGe by ion implantation will cause serious damage to the crystal structures, and result in the formation of poly-crystal SiGe. 相似文献
952.
C.X. Gao F.C. Yu S.Y. Jeong A.R. Choi P. Parchinskiy D.J. Kim H.J. Kim Y.E. Ihm C.G. Kim C.S. Kim 《Journal of magnetism and magnetic materials》2006
GaMnN and Be-codoped GaMnN were grown via molecular beam epitaxy using a single GaN precursor and their structural and magnetic properties were examined. X-ray diffraction and superconducting quantum interference device (SQUID) measurements revealed that the grown layers are homogeneous without precipitates. The saturation magnetization of GaMnN has increased from ∼4 to ∼16 emu/cm3 via codoping of Be. The d–d exchange interaction between Mn atoms was discussed for the ferromagnetism of GaMnN. 相似文献
953.
B. Zhang S. D. Yao K. Wang D. B. Ding Beijing P.R. China Beijing P.R. China Beijing P.R 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(1):9-13
Summary Department of Technical Physics, School of Physics, Peking Unive 相似文献
954.
Oil migration in filled chocolates limits shelf life due to texture changes and loss of visual appeal. Spatial and temporal
oil concentration changes of a two-layer chocolate and peanut butter filling system, which models a filled chocolate, were
monitored by magnetic resonance imaging. Formulations of chocolate varied with respect to particle size, milk fat content
and emulsifier level. Sorption-time experimental data was used to establish the best fit diffusion coefficient for a Fickian
diffusion model. On the basis of the comparison of spatial experimental data to the model, Fickian diffusion alone does not
account for oil migration.
Authors' address: Michael J. McCarthy, Department of Food Science and Technology, University of California, One Shields Avenue,
Davis, CA 95616, USA 相似文献
955.
The surface energies for 24 surfaces of all bcc transition metals Fe, Cr, Mo, W, V, Nb and Ta have been calculated by using the second nearest-neighbor modified embedded atom method. The results show that, for all bcc transition metals, the order among three low-index surface energies E(1 1 0) < E(1 0 0) < E(1 1 1) is in agreement with experimental results and E(1 1 0) is also the lowest surface energy for various surfaces. So that from surface energy minimization, the (1 1 0) texture should be favorable in the bcc films. This is also consistent with experimental results. The surface energy for the other surfaces increases linearly with increasing angle between the surfaces (h k l) and (1 1 0). Therefore, a deviation of a surface orientation from (1 1 0) can be used to estimate the relative values of the surface energy. 相似文献
956.
S. Nakano Y. Kuwano M. Ohnishi 《Applied Physics A: Materials Science & Processing》1986,41(4):267-274
The super chamber, a separated UHV reaction-chamber system has been developed. A conversion efficiency of 11.7% was obtained for an a-Si solar cell using a high-quality i-layer deposited by the super chamber, and a p-layer fabricated by a photo-CVD method.As a new material, amorphous superlattice-structure films were fabricated by the photo-CVD method for the first time. Superlattice structure p-layer a-Si solar cells were fabricated, and a conversion efficiency of 10.5% was obtained.For the fabrication of integrated type a-Si solar cell modules, a laser pattering method was investigated. A thermal analysis of the multilayer structure was done. It was confirmed that selective scribing for a-Si, TCO and metal film is possible by controlling the laser power density. Recently developed a-Si solar power generation systems and a-Si solar cell roofing tiles are also described. 相似文献
957.
The effect of γ-ray irradiation on the magnetic properties of NdFeB and Fe–Cr–Co permanent magnets has been investigated. The magnetic flux loss of two kinds of magnets before and after irradiation was measured. Results show that the effect of γ-ray irradiation on the magnetic properties of sintered NdFeB is not so obvious as that on Fe–Cr–Co magnet. Irradiation-induced damage from γ-ray for the Fe–Cr–Co magnets was characterized for the first time. The decline of permanent magnetic properties of Fe–Cr–Co magnet induced by γ-ray irradiation is reversible except for the maximum energy product (BH)max. The difference of coercivity mechanism between these two kinds of permanent magnets is responsible for the different dependence of magnetic properties loss induced by γ-ray irradiation. 相似文献
958.
Iron oxide catalyst with spinel structure used for dehydrogenation of ethylbenzene is one kind of important catalyst in petrochemical industry. In this work several series of industrial catalyst were prepared with different components and different manufacturing processes. Mössbauer Spectroscopy has been used to determine the optimal components and the better manufacturing process for spinel structure formation. The results may prove useful for producing the industrial dehydrogenation catalyst with better catalytic property. 相似文献
959.
This paper reports the measurement of magnetic properties of the soft magnetic composite material SOMALOYTM 500 in a square sample under different patterns of flux density with 2D magnetic excitations. The test system, principle of measurement, magnetic power loss calculation, and methods of correction for misalignment of H surface sensing coils are presented. The experimental results show that although nominally isotropic, the SOMALOYTM 500 sample exhibits some anisotropy. The results are useful in the design and performance analysis of rotating electrical machines. 相似文献
960.
Summary The normal incidence reflectivity spectrum of excitons in GaAs/Ga1−x
Al
x
As multiple quantum wells is calculated within the local response approximation. It is shown that the reflectivity lineshape
strongly depends on the sample geometry. Using realistic parameters of a multiple quantum well structure, we obtain an excellent
fit of the experimental reflectivity curve, thus giving exciton energies, oscillator strengths and exciton broadening parameters.
Riassunto Lo spettro di riflettività ad incidenza normale degli eccitoni nei pozzi quantistici multipli di GaAs/Ga1−x Al x As è calcolato nell’ambito dell’approssimazione locale. Si mostra con la forma della linea di riflettività dipende in gran misura dalla forma geometrica del campione. Usando parametri realistici di una struttura a pozzi quantistici multipli, si ottiene un’ottima approssimazione della curva di riflettività sperimentale, che fornisce così energie eccitoniche, forze dell’oscillatore e parameri di ampliamento eccitonico.
Резюме В рамках приближения линейного отклика вычисляется спекрт отражательной способности экситонов при нормальном падении для множественных квантовых ям в GaAs/Ga1−x Al x As. Показывается, что форма линии отражательной способности сильно зависит от геометрии образца. Используя реалистические параметры структуры множественных квантовых ям, мы получаем хорошее соответствие с экспериментальной кривой для отражательной способности. Получаются энергии экситонов, силы осцилляторов и парам⪟тры экситонного уширения.相似文献