Model building of disulfide bonds in proteins with known three-dimensional structure

As an aid in the selection of sites in a protein where a disulfidebond might be engineered, a computer program has been developed.The algorithm starts with the generation of Cß positionsfrom the N, C and C atom coordinates available from a three-dimensionalmodel. A first set of residue pairs that might form a disulfidebond is selected on the basis of Cß–Cßdistances between residues. Then, for each residue in this set,S positions are generated, which satisfy the requirement that,with ideal values for the C–Cß and Cß–Sbond lengths and for the bond angle at Cß, the distancebetween S of residue 1 and Cß of residue 2 in a pair(determined by the bond angle at S2) is at, or very close toits ideal value. Usually two acceptable S positions are foundfor each half cystine, resulting in up to four different conformationsfor the disulfide bond. Finally, these conformations are subjectedto an energy minimization procedure to remove large deviationsfrom ideal geometry and their final energies are calculated.User input determines which final conformations are energeticallyacceptable. These conformations are written to a file to allowfurther analysis and e.g. inspection on a computer graphicsdevice.     

二甲基二硫的合成

本文就二甲基二硫的合成方法作了概述，并进行分析、比较，对其发展前景亦作了介绍。     

二硫化碳下游产品的开发及应用进展

介绍了以二硫化碳为原料深加工生产其下游产品─—农药、橡胶硫化促进剂、选矿药剂及其它精细化学品。     

卡尔曼滤波分光光度法同时测定钼(Ⅵ)钨(Ⅵ)钒(Ⅴ)三组分混合体系

在研究了Tiron与钼(Ⅵ)、钨(Ⅵ)、钒(Ⅴ)的显色反应基础上,对采用卡尔曼滤波分光光度法(简称KF法)同时测定钼、钨、钒三组分混合体系进行了探讨。对10份不同比例的钼、钨、钒标准混合液的测定,平均回收率分别为103.4％、102.0％和99.31％。标准偏差分别为3.48％、1.15％及2.16％。应用于工具钢标样及杂多酸合成样的分析,获得满意结果。     

镍钨合金电沉积及其析氢电催化性能的研究

本文研究以钛或铁为基体的Ni-W合金电镀。阴极极化曲线表明，以前为基本的Ni-W合金镀层为阴极，电解300g／L NaCl(25℃)，3．0A／dm2能降低析氢过电势420mV，电解1mol／L MnSO4 0．5mol／L H2SO4能降低810mV。说明Ni-W镀层是析氢的优良电催化阴极。     

A nitric oxide gas sensor based on Rayleigh surface acoustic wave resonator for room temperature operation

A Rayleigh surface acoustic wave (RSAW) resonator with polyaniline/tungsten oxide nanocomposite thin film is investigated as a gas sensor for detecting the presence of nitric oxide (NO) in air. The sensor developed in this work was sensitive to NO gas at room temperature. It is shown that the sensor had a frequency shift of 1.2 ppm when it was exposed to 138 ppb NO. The negative frequency response increased with NO concentration increasing. The response and recovery times of the NO sensor in this work were about 20-80 s. In addition, this RSAW sensor also exhibited reversibility and repeatability to the presence of NO gas. Especially, the presented sensor showed high selectivity with NO gas to separate from NO₂ and CO₂ gases.     

Solution Phase Reactions of Organomolybdenum Friction Modifier Additives for Energy Conserving Engine Oils

The reactivity of MoDTC and ZnDTP in hydrocarbon solution was examined in detail under non-oxidizing conditions. These observations revealed increased reaction rates when polar solvents and/or short alkyl groups are encountered. Through the use of molecular modeling, it is shown that the major influences over MoDTC/ZnDTP reactivity are hard/soft acid/base and solvation interactions. As a result of this work, both MoDTC and ZnDTP appear to exist as ion pairs in engine oil formulations.     

崇义地区淘锡坑钨矿的地质特征与成矿时代

现如今矿业的发展在我国经济发展建设中占据着重要的地位。此次我们研究的是江西崇义县的一处矿区,此地区的淘锡坑钨矿是我国主要矿产资源产出地之一,含有较多的以英脉型黑钨矿为主的钨多金属矿床。崇义地区淘锡坑钨矿的成矿特征受地质特征的影响,成矿受北西向断裂控制,与燕山期岩浆作用有关。     

废SCR脱硝催化剂钒钨提取研究进展

含有钒、钨和钛的选择性催化还原催化剂在许多工业应用中被广泛还原氮氧化物。各行业脱硝催化剂正在进入报废更换高峰期,处理废催化剂回收有价金属迫在眉睫。将回收的钒、钨、钛用于生产新型催化剂或其他产品,可形成循环经济。对废脱硝催化剂钒钨提取工艺进行详细综述,重点介绍钒钨浸出和钒钨分离方法。     

等离子喷涂碳化钨涂层组织与喷涂条件的关系

将粉末直接输送到低功率等离子喷枪内部阴、阳极之间，携带粉末气体转变为等离子体，在输入电功能1．8－5．6kW条件下，利用低能等离子喷涂铸造－破碎和烧结－破碎两种碳化钨粉末，沉积效率达到80％以上。同时研究了Ar-N2、Ar-H2两种不同等离子气体和不同等离子工艺参数下涂层的组织结构、硬度等的关系。Ar-Z2气体成分对涂层硬度的影响 大于Ar-H2。并且推荐了适合于内送粉低功率等离子喷涂金属碳化钨的工艺。