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61.
62.
K. W. Cheah L. C. Ho J. B. Xia J. Li W. H. Zheng W. R. Zhuang Q. M. Wang 《Applied Physics A: Materials Science & Processing》1995,60(6):601-606
Photoluminescence studies on porous silicon show that there are luminescence centers present in the surface states. By taking photoluminescence spectra of porous silicon with respect to temperature, a distinct peak can be observed in the temperature range 100–150 K. Both linear and nonlinear relationships were observed between excitation laser power and the photoluminescence intensity within this temperature range. In addition, there was a tendency for the photoluminescence peak to red shift at low temperature as well as at low excitation power. This is interpreted as indicating that the lower energy transition becomes dominant at low temperature and excitation power. The presence of these luminescence centers can be explained in terms of porous silicon as a mixture of silicon clusters and wires in which quantum confinement along with surface passivation would cause a mixing of andX band structure between the surface states and the bulk. This mixing would allow the formation of luminescence centers. 相似文献
63.
Wen-bao Li Ya-hui Zhuang Dai-zheng Liao Geng-ling Wang 《Transition Metal Chemistry》1994,19(3):315-318
Summary Two -phenoxo-bridged binuclear copper(II) complexes, [Fsal(GG)2Cu2Cl3]·H2O (1) containing an exogenous chloride-bridge and [Fsal(GG)2Cu2(OH)](ClO4)2·H2O (2) containing an exogenous hydroxide-bridge, where {Fsal(GG)2 = 2,6-bis[N-(acetylglycine)-imino-methylene]-4-methylphenol}, were synthesized. The complexes were characterized be several spectroscopic methods. According to variable temperature magnetic susceptibility measurements (4–300 K), the hydroxide-bridged complex (2) has a weak antiferromagnetic spin exchange integral (J =- 23.6 cm), while the chloride complex (1) has an unusual weak ferromagnetic spin exchange integral (J = + 30.9 cm); both complexes have similar optical spectra in the aqueous solutions. 相似文献
64.
The kinetics of the acid catalyzed hydrolysis of 2-aminoethanethiolsulfate (AETS) ions were investigated. The dependence of the hydrolysis rate constant on acidity and temperature was determined. The hydrolysis rate equation can be expressed as where Ho is the Hammett acidity function. The rate constant, k, can be expressed as The pKa's for the compound were measured and literature value of pKa was found to be in error. The values determined in this study are pKa1 < ?0.5 and pKa2 = 9.1 ± 0.1. General acid catalysis of the hydrolysis reaction was found not to proceed to a significant degree. © 1994 John Wiley & Sons, Inc. 1 This article is a US Government work and, as such, is in the public domain in the United States of America. 相似文献
65.
SynthesisandStructureof[(C_2H_5)_4N][Mo_3(μ_3-O)(μ-Cl)_3(μ-CH_3CH_2COO)_3Cl_3]ZhuangHong-Hui;WuDing-Ming;HuangJian-Quan;HuangJin-L... 相似文献
66.
Jian Zhuang Julius M. Hastings Lester M. Corliss R. Bau Chiau-Yu Wei R. O. Moyer Jr. 《Journal of solid state chemistry》1981,40(3):352-360
Neutron diffraction data have been collected on a powdered sample of Sr2IrD5 over a range of temperatures. The compound, which is cubic at room temperature, has been found to exhibit a gradual transformation to a tetragonal phase in the temperature range 200-140 K. As a result of the transition, deuterium atoms which randomly occupy sixfold positions in the cubic phase, become tetragonally ordered. A small fraction of the cubic phase remained untransformed at 4.2 K. Both the cubic and tetragonal structures are consistent with square pyramidal IrD5 units with average Ir---D distances of 1.714 and 1.718 Å, respectively. Agreement factors, R1, for the two structural analyses are 3.44 and 4.94%. 相似文献
67.
68.
It is usually reported that reaction between carbonyl and P2S5 produce thiono group compound. The Products from carbonyl after ammonolysis and hydrazinolysis have the very import applied value in the synthesize of heterocyclic compound. Sulfuration reation if a nucleophilic attack, SPS2 anionsid obtained from P2S5 in the organic sovent, rather easier than thereationsof scheeren’s reagent. The reation mechanism is as follows: The reation speed has something todo with the electronegative of… 相似文献
69.
70.
Under steady-state conditions, the current equations of the second-order EC, ECE and DISPI reactions at microdisk, microspherical and microring electrodes are derived with the aid of the concept of the reaction layer. The conditions under which these equations would be valid are also discussed. Using these equations, methods to determine the kinetic parameters for the second-order EC, ECE and DISPI reactions are presented. The reduction of 2,6-diphenyl-pyrylium cation and oxidation of triphenylamine were investigated as examples of the second-order EC and ECE reactions. 相似文献