AB5型储氢合金的高倍率放电性能及机制

本文研究了储氢合金表面处理，粒度分布，稀土组成和添加剂硼对储氢合金高倍率放电性能的影响及机制的探讨。采用物理方法和化学方法对储氢合金进行表面处理，提高了合金表面电化学反应速度，同时促进了氢原子在合金本体中的扩散，从而改善了合金的活化性能、放电容量和高倍率放电能力。储氢合金粉粒度太粗和太细都使合金电极阻抗增大，导致放电容量和高保率放电能力下降，而且大电流放电平台也较低，选择合适的储氢合金粉粒度分布既可提高合金的活性和放电容量又能改善合金高倍率放电能力。随着合金中La含量的增加和Ce含量的减少，提高了合金的表面活性，使合金的大电流放电性能得到改善。储氢合金中加入元素B，使合金易粉化并形成少量的第二相，不但改善了合金的活性和放电容量而且显著地提高了合金高倍率放电能力。     

次甲基硅SiH与H2X(X=O,S)反应的热力学及动力学性质研究

在量子化学对SiH与H₂O和H₂S反应计算的基础上,运用统计热力学和Wigner校正的Eyring过渡态理论,计算了上述两反应在200～2000 K温度范围内的热力学函数、平衡常数、频率因子A和速率常数随温度的变化。计算结果表明,两反应在低温下具有热力学优势,而在高温下具有动力学优势。比较两反应的计算结果发现,在相同的温度下,SiH与H₂O反应比SiH与H₂S反应放热较多,但速率常数却较小。SiH与H₂O反应和前文报道的SiH与HF反应的比较表明,SiH与H₂O反应放热较少,而且在相同温度下,速率常数也较小。     

中国化学会《化学知识丛书》编委会在桂林召开

为了开展化学知识的普及工作,中国化学会筹备组织了《化学知识丛书》编委会,并于1979年2月7日至12日在桂林召开了第一次工作会议。出席编委14人,列席4人。中国化学会副理事长王序同志参加了这次会议,他代表化学会理事会宣布聘请北京大学化学系主任张青莲同志担任《化学知识丛书》主编,袁翰青、胡秉方、胡亚东三同志担任副主编。丛书主编张青莲同志在开幕式上讲了话,与同时召开的物理、生物知识丛书编委工作会议的同志们交流了编写工作中的问题及设想。会上老专家,老教授与中青年科技人员认真、热烈地讨论了这套丛书的读者对象及编写体例,确定它是向具有高中以上文化程度的青年普及化学知识的中级科普读物,同时可供中等学校教师、科技人员和干部参     

Crystal Structure of Chlorinate （N,N-1,3-Dibenzyl-benzimidazole） Hydrate

1 INTRODUCTION Benzimidazole is an interesting heterocyclic ring because it is present in various naturally occurring drugs, such as omeprazole, astemizole and emedastine difumarate[1]. The efficacy of substituted benzimidazoles in the treatment of parasitic infections is well known[2～4], and the pharmacophores in parasitic chemotherapy are established by benzimidazole-substituted moieties. Bis(2-benzimidazoles) and some substituted bis- (benzimi-dazol-2-yl) alkanes have attracted much…     

Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing N,N-Dialkyldithiocarbamate Moiety

Introduction As an important type of fungicides, triazole compounds are highly efficient, low poisonous and inward absorbent.1-3 At present, the studies on triazole derivatives are mainly concentrated on compounds with triazole as the only active group. The report of triazole compounds that contain both triazole group and other active group in a single molecule has rarely been found. Dialkyl-substituted dithiocarbamate salts have also shown interesting biological effects.4 N,N-Dialkyldithio-…     

乳状液膜处理含铬废水的研究

本文对乳状液膜从含铬(VI）废液中提取铬进行了研究，考察了影响铬迁移的几种因素；内外水相pH、表面活性剂、流动载体、添加剂等。结果表明，在合适的操作条件下，当废水中铬的含量在4．8×10^-3mol·L^-1时，经过一级液膜处理，废水中铬的提取率可达99%以上，提余液可以直接排放。     

一维链状配位聚合物[Cd(N-MeIM)2(SCN)2]n的结构表征和电化学性能研究(英)

A novel cadmium(Ⅱ) isothiocyanate complex [Cd(N-MeIM)₂(SCN)₂]_n(N-MeIM=N-methylimidazole) has been prepared and characterized by spectroscopic analysis and crystallographic method. The title compound crystallize in the Triclinic system, space group P1, with lattice parameters a=0.589 50(12) nm, b=0.785 70(16) nm, c=0.882 00(18) nm, α=110.98(3)°, β=106.49(3)°, γ=95.08(3)°, and Z=1. The title compound exhibits an infinite chain structure in which each pair of Cd atoms is bridged by two η-1,3-SCN^- groups. The unique Cd atom lies on an inversion centre and the coordination sphere is completed by two N-MeIM N atoms to form a CdS₂N₄ octahedron. The polymeric chains are further extended into three-dimensional network via π…π stackings interactions between the imidazole rings. The cyclic voltammetry behaviors of the compound on glass carbon electrode showed a typical irreversible process. CCDC: 265283.     

A Density Functional Theory Study on Electronic Structure and Second—order Nonlinear Optical Properties of Some Push—Pull Molecules

Time-dependent density-functional theory(TDDFT)has been applied to calculate the electronic structure and second-order nonlinear optical(NLO) properties of some organic molecules.The two-dimensional(2-D)charge transfer charateristics of calculated molecules were studied and compared with corresponding experimental results.All the theoretical results agree well with the measurement.For 2-D molecule with two-fold symmetry,the dominant charge transfer is off-diagonal,while for three-fold symmetry 2-D molecule,the dominant charge transfer is not only between branches and central group but also among branches.     

云南重楼中的新甾体皂苷

从云南重楼Paris polyphylla Sm. var. yunnanensis(France. )Hand.-Mazz.的干燥根茎中分离鉴定了4个甾体皂苷(1~4), 其中化合物1是新化合物, 采用波谱技术鉴定其结构为24-O-β-D-吡喃半乳糖基-(23S,24S)-螺甾-5, 25(27)-二烯-1β,3β,23,24-四醇-1-O-β-D-吡喃木糖基(1→6)-β-D-吡喃葡萄糖基(1→3)[α-L-吡喃鼠李糖基(1→2)]-β-D-吡喃葡萄糖苷.     

基于G-四链体-氯化血红素DNA酶比色法测定银离子和汞离子传感器的构筑

利用G-四链体DNA(5′-CTGGGAGGGAGGGAGGGA-3′)与氯化血红素结合形成G-四链体-Hemin DNA酶,其能高效催化H_2O_2氧化反应底物由无色变为绿色,当溶液中有Ag~+或Hg~(2+)存在时会阻碍该DNA酶的形成,导致绿色溶液变浅。基于此,建立了比色法测定Ag~+和Hg~(2+)的传感器。在最佳实验条件下,溶液的吸光度与Ag~+和Hg~(2+)浓度分别在100.0～1 000.0 nmol/L和80.0～800.0 nmol/L范围内具有良好的线性关系,检出限(3δ/Slope)分别为55.9 nmol/L和64.3 nmol/L。该方法具有较好的选择性,采用该方法对实际样品进行测试,结果满意。