Mg基非晶合金及La-Mg-Ni基复合物储氢电极的结构与电化学性能

Mg50Ni50非晶合金具有较高的初始放电容量（500mAh／g），有希望成为Ni-MH二次电池的负极合金材料。但较差的循环稳定性限制了它的进一步开发和应用。为此，本研究采用机械合金化方法，基于Mg侧进行元素替代，获得了四元Mg0.9-xTi0.1PdxNi（X=0．04-0．1）储氢合金。XRD和TEM分别从宏观和微观角度证实该系列合金仍为非晶态合金。本研究还发现，随着Pd含量的增加，腐蚀电流降低；合金的抗腐蚀能力提高。当Pd含量达到0．1的时候，Mg0.8Ti0．1Pd0．1Ni合金的耐蚀能力达到最大，其容量保持率也达到最高，经80次循环后放电容量仍然保持在200mAh／g以上。 AB3型La-Mg-Ni储氢合金与Mg基合金类似之处在于：具有较高的初始放电容量但循环容量保持率较低。为此，本研究将AB3型La0.7Mg0.3Ni3.5合金与具有较高循环稳定性的AB2型Ti0.17Zr0．08V0.35Cr0．1Ni0．3合金相复合，获得新型AB3-AB2复相合金。XRD研究表明复合物中La0．7Mg0．3Ni3．5和Ti0.17Zr0.08V0．35Cr0．1Ni0．3仍旧保持原有结构。扫描电镜（SEM）研究发现，复合物颗粒的平均尺寸在50μm左右。由于Ti0．17Zr0．08V0.35Cr0．1Ni0．3相的防护，复合物的耐腐蚀能力及100次循环容量保持率（62．3％）得以显著提高。     

乙醇-环己烷体系中NaI活度系数的测定与计算

由于非水溶剂的应用日趋广泛,促使物理化学工作者对于溶剂和溶液性质进行研究,同时开展了有关物理化学数据的测定和积累工作,以利于指导实践[1]。目前文献报道含水混合溶剂中的电解质活度系数较多,但非水混合溶剂中电解质活度系数报道较少。电解质浓溶液活度系数的计算方法目前应用较广的是Pitzer半经验算法[2]。Pitzer的算法中具体物系的β(0)、β(1)等系数需从实测活度系数数据拟合求得。孙仁义等通过测定汽液平衡盐效应的方法研究了盐在混合溶剂中的活度系数[3-4]。最近孙仁义等[5]提出了双液比固定条件下含盐体系汽液平衡数据热力学一…     

Synthesis of 1, 4-Bis[3-N-propionyl-2-aryl-1, 3, 4- oxadiazoline-5-yl]phenylenes

1, 3, 4-Oxadiazoline derivatives are found to possess significant biological activities such as antifungal1, insecticidal2, CNS depressant3-5, anticonvulsant effects and plant growth accelerator. They are highly important heterocycles, and have been used …     

镍基气凝胶催化CH4-CO2重整制取合成气反应的研究 Ⅲ.影响催化剂积碳性能因素的探讨

考察了823K焙烧的干凝胶xNCA550、气凝胶aNCA550及浸渍型催化剂iNCA550在923K、1073K、1173K反应温度下的积碳行为，对催化剂表面碳的活性及类型进行了分析，并探讨了影响催化剂积碳的因素。实验结果表明，随反应温度的提高，催化剂的积碳能力减弱，尤以气凝胶催化剂aNCA550明显。催化剂的积碳主要发生在反应的初期，反应温度越高，到达积碳量相对稳定期所需要的时间越短；随着反应时间的延续，催化剂积碳量缓慢增长，并且表面碳的活性降低。催化剂的酸性和镍晶粒大小是影响其积碳性能的主要内在因素，而它们对积碳的影响程度受反应温度的影响，反应温度越高，催化剂表达酸性中心利于积碳的作用越小，小晶粒镍抑制催化剂积碳的能力越强。     

Theoretical Studies on Electronic Spectra and Second-order Nonlinear Optical Properties of Barbituric Acid Derivatives Substituted with Schiff Base

Barbituric acid (BA) is a very important kind of compound in biological chemistry and medicine. It can be applied in abirritative medicine and antioxidants.1 It is an important sort of raw material for organic synthe-sis.2 It predicts the important reactive mechanism for organic synthesis.3 Some investigations for NLO prop-erties of a series of BA derivatives have been reported by Feng and coworkers in the view of theory.4,5 The Schiff base has extensive application in the fields of organi…     

一种新的ⅥA族化学反应振荡器：Na_2S_2O_8－KSCN－CuSO_4体系

一种新的ⅥＡ族化学反应振荡器：Ｎａ_２Ｓ_２Ｏ_８－ＫＳＣＮ－ＣｕＳＯ_４体系林娟娟，高庆宇，宋浩，黄振炎，赵学庄（南开大学化学系，天津，３０００７１）关键词化学振荡，非线性化学反应，过硫酸盐，硫氰酸盐自经典的均相ＢＺ化学振荡反应体系的发现及提出耗散结构...     

稀土金属与N—亚水杨基甘氨酸的配合物的合成与鉴定

使用甘氨酸与水杨醛合成的希夫碱试剂，与轻稀土金属Ｌａ（Ⅲ），Ｐｒ（Ⅲ），Ｓｍ（Ⅲ），Ｅｕ（Ⅲ），Ｙ（Ⅲ）形成配合物，分析此配合物结构，证明此配合物有荧光性质。     

三甲基硅烷基丙炔与五甲基二硅烷基丙炔共聚物膜及其气体透过性

研究了三甲基硅烷基丙块与五甲基二硅烷基丙块共聚物〔poly(TMSP-co-PMDSP)〕的成膜特点。poly(TMSP-co-PMDSP)膜的气体透过系数分别为:P_(O2):4×10~3～12×10~3,P_(N2):3×10~3～8×10~3和P_(CO2):2×10~4～4×10~4barrer,气体透过稳定性低,透过行为偏离第二Fick定律,过系数下降,其中溶解系数降低的比例远大于扩散系数的增加比例,在含有凝聚性气体的环境里,膜的气体透过出现表面吸附控制的特征。     

Theoretical Study of the Low-Lying Excited States of Butoxy Radicals and Non-Radiative Decay Routes

The potential energy surfaces for the butoxy radical dissociation into R·＋O on the six low-lying electronic states have been determined with the combined CASSCF and MR-CI methods. The isomerization reactions between the different conformers of 1- and 2-butoxy radicals at the X and B states have been also investigated with the MP2, B3LYP, and CASSCF methods. The non-radiative decay mechanisms of butoxy radicals at the B state have been characterized with the computed potential energy surfaces and intersections. Supported by recent LIF experimental results, it was predicted that the t-butoxy radical would predissociate via the B/C intersection. As to 1- and 2-butoxy radicals, the relative energies of the transition states for the isomerization reactions between conformers at the B state are much lower than those of the B/C intersections, resulting in the predominance of the isomerization in the decay of the B state for 1- and 2-butoxy radicals.     

Chemoselective Dehydrogenation of 3-[2-（3,4-Dihydro-1-naphthalenyl）ethyl]imidazolidine-2,4-diones： a New and Convenient Synthesis of 13,16-Diazaequilenin analogs

The synthesis of the title compounds starting with the chemoselective dehydrogenation of 3-[2-(3,4-dihydro-1-naphthalenyl)ethyl]imidazolidine-2,4-diones has been described.