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151.
Reactions of 2‐isopropoxy‐1, 3, 2‐ benzodioxaborole with equivalent amounts of Schiff base ligands having two hydroxyl groups ( 1a–3a ) yield mononuclear derivatives with one residual hydroxy group. The reactions of these mononuclear derivatives with hexamethyldisilazane in a 2:1 ratio yield heterodinuclear derivatives. All these newly synthesized derivatives have been characterized by elemental analyses and molecular weight measurements. Tentative structures have been proposed on the basis of IR and NMR (1H, 13C, 11B,29Si)spectral data and Fab‐mass studies. Schiff bases and their corresponding mono‐ and heterodinuclear derivatives of boron have also been screened for antifungal activities. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
152.
153.
A complete inspection of the capabilities of reflectance anisotropy spectroscopy (RAS) in studying the adsorption of molecules or atoms on the Si(0 0 1)-(2 × 1) surface is presented. First, a direct comparison between RA spectra recorded on the clean Si(0 0 1)-(2 × 1) and the corresponding topography of the surface obtained using scanning tunneling microscopy (STM) allows us to quantify the mixing of the two domains that are present on the surface. Characteristic RA spectra recorded for oxygen, hydrogen, water, ethylene, benzene are compared to try to elucidate the origin of the optical structures. Quantitative and qualitative information can be obtained with RAS on the kinetics of adsorption, by monitoring the RA signal at a given energy versus the dose of adsorbate; two examples are presented: H2/Si(0 0 1) and C6H6/Si(0 0 1). Very different behaviours in the adsorption processes are observed, making of this technique a versatile tool for further investigations of kinetics. 相似文献
154.
H. Ohyama E. Simoen C. Claeys K. Takakura H. Matsuoka T. Jono J. Uemura T. Kishikawa 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):533
Results are presented of a detailed study of the effects of high-temperature 4-MeV neutron irradiation on the performance degradation of Si pin photodiodes together with the radiation-induced defects, observed by deep level transient spectroscopy. The degradation of the device performance and the introduction rate of the lattice defects decrease with increasing sample temperature during irradiation. For a 250°C irradiation, the reduction of the reverse current is only 20% of the starting value. This result suggests that the creation and recovery of the radiation damage proceeds simultaneously at high temperatures. Carbon-related complex as hole capture levels is also mainly responsible for the device degradation for high-temperature neutron irradiation. 相似文献
155.
156.
Hydrogenated amorphous-Si/SiO2 (a-Si:H/SiO2) superlattices with different a-Si : H thickness in the range of a few nanometers have been fabricated by ultra high vacuum evaporator (UHV evaporator). The photoluminescence (PL) of our superlattices is observed in the visible spectral region and the peak energy shifts to higher energy as the a-Si : H layer thickness decreases. The temperature dependence of the PL spectra reveals four sub-bands by fitting. Bands at 2.2, 1.9, 1.65 and 1.45 eV are detected and are attributed to E′δ centers, nonbridging-oxygen–hole centers (NBOHC), Si/SiO2 interface and a-Si : H layer, respectively. We explain the overall blueshift of the PL spectra by the modification of the contribution of these sub-bands. 相似文献
157.
SOI新结构——SOI研究的新方向 总被引:2,自引:0,他引:2
SOI(silicon-on-insulator:绝缘体上单晶硅薄膜)技术已取得了突破性的进展,但一般SOI结构是以SiO2作为绝缘埋层,以硅作为顶层的半导体材料,这样导致了一些不利的影响,限制了其应用范围。为解决这些问题和满足一些特殊器件/电路的要求,探索研究新的SOI结构成为SOI研究领域新的热点。如SOIM,GPSOI,GeSiOI,SionAlN,SiCOI,GeSiOI,SSOI等。文章将结合作者的部分工作,报道SOI新结构研究的新动向及其应用。 相似文献
158.
Time-ResolvedPhotoluminescenceSpectraofPorousSiFEIHao-sheng,HANLi,CHEYan-long,NIERui-juanandLITie-jin(DeparrmentofPhysicsandD... 相似文献
159.
Ye J. Kojima N. Furuya K. Munakata F. Okada A. 《Journal of Thermal Analysis and Calorimetry》2002,69(3):1031-1036
A micro-thermal analysis technique was applied to investigate advanced silicon nitride materials, which exhibit high thermal
conductivity. Local thermal properties in the microstructure were evaluated, and the grain boundaries were observed to have
lower thermal conductance than the Si3N4 grains. It was found that thermal conductance both in the grains and boundaries was lowered by the addition of the sintering
aid Al2O3, which is soluble in Si3N4 grains. This indicates that high thermal conductivity in silicon nitride ceramics is achieved both by grain growth, leading
to a reduction in boundary density, and by eliminating soluble elements in silicon nitride grains.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
160.
注入Si中的稀土离子Er3+的光学特性 总被引:2,自引:1,他引:1
用离子注入方法,将稀土离子Er3+注入到n-Si单晶中,通过对其低温(77K)光致发光光谱的测量,研究其光学特性.结果表明,注入剂量控制在1×1012cm-2~1×1015cm-2范围,退火温度控制在900℃~1100℃时,样品的主要发光峰值位于1.54μm左右.研究了样品的光致发光光谱随注入剂量、退火温度的变化关系,给出峰值在1.54μm附近的未分辨开的谱线的半宽为16.4meV. 相似文献