DFT/B3LYP方法探索C6H5(CH3)2SiOH的结构和化学键特性

二甲基苯基硅醇易通过蒸馏的方法进行分离提纯,进而制备高纯硅,但其化学键特性的实验数据较为缺乏,笔者运用密度泛函理论DFT/B3LYP方法,采用6-311++G**基组进行计算,首先对二甲基苯基硅醇的初始构型进行完全开放的几何构型全优化,之后结合能量分析、电荷分析和自然键轨道分析(NBO)考察了二甲基苯基硅醇平衡构型的分子性质,得出二甲基苯基硅醇分子的化学键特性：1）苯基和甲基对羟基上的O-H键影响甚微,但使Si-O键有所增强;2）Si与苯环上C原子间的键强度较弱,Si-O键相对较强,O-H键最弱;3）苯环上C原子间电子离域化程度相对较高,O的孤对电子流向Si-C反键轨道,可略为削弱Si-C键强度。填补了其化学键特性方面的空白,为涉及二甲基苯基硅醇的化学反应提供了理论基础。     

Effects of five heavy metals at sub-lethal concentrations on the growth and photosynthesis of Chlorella vulgaris

The impact of sub-lethal concentrations(0.05,0.5,5 μmol L 1) of the heavy metals copper(Cu),chromium(Cr),zinc(Zn),cadmium(Cd) and lead(Pb) on the growth and photosynthesis of Chlorella vulgaris was studied during 96 h exposure experiments.The results showed that the effects of these five metals on the growth of Chlorella vulgaris were dependent on both concentration and exposure time.It was found that 5 μmol L 1 treatments of Cu,Cr,Zn,Cd and Pb significantly inhibited the growth of Chlorella vulgaris,and the effect became weaker with an increase in exposure duration.Different effects on chlorophyll fluorescence were found for different metals,with Cu and Cr having an inhibiting effect and Zn and Cd having a promoting effect.The effects of heavy metals upon the growth and photosynthesis of Chlorella vulgaris were independent of each other and not causally related.     

Single atoms in the ring lattice for quantum information processing and quantum simulation

We have demonstrated preparing and rotating single neutral rubidium atoms in an optical ring lattice generated by a spatial light modulator, inserting two atoms into a single microscopic optical potential efficiently by dynamically reshaping the optical dipole trap, trapping single atoms in a blue detuned optical bottle beam trap, and confining single atoms into the Lamb-Dicke regime by combining red and blue detuned optical potentials. In combination with the manipulation of internal states of single atoms, the study is opening a way for research in the field of quantum information processing and quantum simulation. In this paper we review the past works and discuss the prospects.     

浅谈《化学海洋学》理论教学改革

通过近几年来对《化学海洋学》理论课程教学工作的归纳与总结,提出关于《化学海洋学》理论课程教学的一些心得与体会。本文分别从教学内容、教学方法、教案的设计、考核方式几个方面进行探讨．为提高《化学海洋学》理论课程的教学质量提供支撑。     

钢丝磨削试验研究

砂带磨削作为一种新工艺,在机械加工领域发挥着越来越大的作用,满足了各种加工要求。本文简单介绍了砂带磨削的概念,阐述了一个针对钢丝表面除锈的新型砂带磨削设备的工作原理及其机床的主要机构,并通过试验研究磨削压力、金属去除率、砂带磨损、磨削比、磨削深度、钢丝走速之间的关系,为砂带修磨线材生产线提供了合理的磨削工艺参数。     

Effects of SrTiO3 buffer layer on structural and electrical properties of Bi3.15Nd0.85Ti3O12 thin films prepared by a chemical method

Ferroelectric Bi3.15Nd0.85Ti3O12 (BNT) thin films have been grown on Pt/Ti/SiO2/Si substrates at 750 ℃ by a chemical solution deposition method using SrTiO3 (STO) as a buffer layer.The influence of STO...     

铜铝异种金属钎焊接头的电化学腐蚀性能研究

通过电化学Tafel曲线的测试,在室温3．5％氧化钠溶液中,对铜铝异种金属钎焊接头的电化学腐蚀性能进行了研究。结果表明：在钎焊过程中,施加一定压力,在一定的保温温度下,延长保温时问,可以提高接头的耐腐蚀性能。     

重金属污染土壤的修复技术研究

土壤污染已经成为一个全球性的环境问题之一,而重金属污染在土壤污染中占有很大的比重,对人类生产和生活以及生态环境造成很大的威胁。文中先针对造成土壤重金属污染的原因进行了分析,后从工程措施、物化修复、化学修复、生物修复、自然修复、及组合修复技术等几个方面分别阐述了重金属污染土壤的修复技术及其研究进展．给出了今后进行重金属污染修复的建议。     

理欲之辨的流变及现代价值

理欲之辨是中国传统哲学论及的重要内容之一。先秦诸子百家是＂理欲＂思想的源头之处,宋明时期程朱、陆王等提出了＂以理压欲＂和李贽提出＂以欲胜理＂的理欲观,王夫之批判了他们并提出了＂以理导欲＂的理欲观,戴震则主要继承了王夫之的＂理寓欲中＂的观点,坚持理欲统一观。文章通过对＂理欲之辨＂源流嬗变的历史探讨,深刻理解每个阶段理欲观的真正内涵,凸显其发展轨迹,阐释其现代价值。     

警检配合与侦查监督

我国刑事诉讼法规定公安机关与检察机关应当互相配合,同时规定检察机关对公安机关侦查活动进行监督。然而,警检配合与侦查监督具有矛盾性：加强警检配合会削弱侦查监督;加强侦查监督则会使警检难以相互配合。我国应以提高对犯罪的有效追诉为目标构建相互配合与协作的警检关系。同时,应当完善侦查权制约机制以防止侦查权的滥用。