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81.
The range of applicability of the mixed-boundary-value method for calculating spreading resistance for a homogeneous slab with an effective contact-radius source and backed by a substrate of arbitrary but finite resistivity is investigated. Solutions are presented in terms of the correction factor and the source current density distributions for a slab of varying thickness and with various high-resistivity substrates. The correction factors for different schemes of calculation are correctly obtained by means of introducing an additional current source of opposite sign, but with the same absolute value, located at the drain point contact. This combination of source and drain currents gives the true value for the potential distribution along the surface of the semiconductor. This, in turn, leads to new terms in the equations obtained for the correction factors, which have been omitted in previously published works. A comparison between several schemes of calculation is presented. Within the framework of “uniform” and “variable” current distributions underneath the contact probe, there are two limits for the correction factor. A model based on a combination of these approaches is discussed, and a comparison between the proposed method and the Schumann–Gardner formulation is made. Received: 30 January 2002 / Accepted: 30 January 2002 / Published online: 28 October 2002 RID="*" ID="*"Corresponding author. Fax: +7-095/531-83-54, E-mail: telkom@df.ru  相似文献   
82.
Anti-reflection coatings of solar cells have been fabricated using different techniques. The techniques used include SiO2 thermal oxidation, ZnO/TiO2 sputtering deposition and porous silicon prepared by electrochemical etching. Surface morphology and structural properties of solar cells were investigated by using scanning electron microscopy and atomic forces microscopy. Optical reflectance was obtained by using optical reflectometer. I-V characterizations were studied under 80 mW/cm2 illumination conditions. Porous silicon was found to be an excellent anti-reflection coating against incident light when it is compared with another anti-reflection coating and exhibited good light-trapping of a wide wavelength spectrum which produced high efficiency solar cells.  相似文献   
83.
IR光谱分析PEO/V2O5纳米复合材料结构   总被引:1,自引:0,他引:1  
聚合物溶液直接嵌入法制备 PEO/ V2 O5纳米复合材料。由红外光谱 (IR)表征了 PEO与氧化物层之间的相互作用。V2 O5干凝胶的钒氧双键 (V=O)主要与层间聚合物 PEO中的醚氧键 (Oet)发生作用 ,以Oet…V=O形式存在  相似文献   
84.
We present the next‐to‐next‐to‐leading order post‐Newtonian (PN) spin(1)‐spin(2) Hamiltonian for two self‐gravitating spinning compact objects. If both objects are rapidly rotating, then the corresponding interaction is comparable in strength to a 4PN effect. The Hamiltonian is checked via the global Poincaré algebra with the center‐of‐mass vector uniquely determined by an ansatz.  相似文献   
85.
Characterization and testing of an L‐shaped laterally graded multilayer mirror are presented. This mirror is designed as a two‐dimensional collimating optics for the analyzer system of the ultra‐high‐resolution inelastic X‐ray scattering (IXS) spectrometer at National Synchrotron Light Source II (NSLS‐II). The characterization includes point‐to‐point reflectivity measurements, lattice parameter determination and mirror metrology (figure, slope error and roughness). The synchrotron X‐ray test of the mirror was carried out reversely as a focusing device. The results show that the L‐shaped laterally graded multilayer mirror is suitable to be used, with high efficiency, for the analyzer system of the IXS spectrometer at NSLS‐II.  相似文献   
86.
87.
A time‐resolved intensified charge coupled device‐based Raman microspectrometer system dedicated to the study of solid samples is described, offering good optical, temporal and spatial resolution. The advantages of this approach are demonstrated on Al2O3:Cr3+, obtaining for the first time the temporal evolution of the excited state transition Ē → 2Ā. Moreover, the time dependence of the luminescence due to the chromium ion was also determined by the same Raman device. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
88.
We report the preparation of Pt–CeO2 nanoparticles on the multi-walled carbon nanotubes (MWNTs) by a reverse micellar method. Transmission electron microscopy (TEM) analysis indicated that well-dispersed small Pt–CeO2 nanoparticles were formed on the MWCNTs. X-ray diffraction (XRD) analysis confirmed the formation of the Pt–CeO2 nanoparticles on the MWNTs. Cyclic voltammetry (CV) results demonstrated that the Pt–CeO2/MWNT exhibited a higher methanol oxidation than did the Pt/MWNT catalyst. The CO stripping test showed that CeO2 can make CO stripped at a lower potential, which is helpful for CO and methanol electro-oxidation.  相似文献   
89.
Complex concentration‐dependence of surface‐enhanced Raman scattering (SERS) and UV–Vis absorption of Ag‐nanoparticles (AgNPs) mixed with Gly has been observed. Surprisingly, with decreasing Gly concentration, a new band in UV–Vis absorption of AgNPs/Gly mixtures is found to red‐shift with increasing intensity, until a turning point at a critical concentration. Further diluting Gly, the new band blue‐shifts with decreasing intensity. Similarly, the SERS intensities of Gly bands at 615 and 905 cm–1 consistently increase with decreasing Gly concentrations, reaching maxima at the critical concentration. This agrees consistently with the variation in position and intensity of the new developing plasmon absorption band. Interestingly, transmission electron microscopy (TEM) revealed Gly‐induced modifications of AgNPs, including a reassembling and increasing aspect ratio with deceasing Gly concentration. The concentration‐dependent behavior of UV–Vis absorption, SERS, and TEM of AgNPs/Gly mixtures could be due to the complex nature of Gly‐AgNPs interaction depending on the molecular density, as supported by TEM images. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
90.
A novel diced spherical quartz analyzer for use in resonant inelastic X‐ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53 meV at the Ir L3 absorption edge (11.215 keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr3Ir2O7 sample is shown.  相似文献   
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