酯对钼系Ziegler-Natta催化剂引发丁二烯聚合的影响

以MoCl_4(Mo)为主催化剂,甲苯氧基二异丁基铝(Al)为助催化剂,在加氢汽油溶剂中,研究了8种酯对丁二烯(Bd)聚合的影响。结果表明,凡是能够溶解在酯中的Mo与Al所组成的二元催化体系,大多能很好地引发Bd聚合,并有较高的催化活性。酯的主要作用是增加Mo在加氢汽油中的溶解性,对聚合物的分子量影响不大,对微观结构几乎无影响。     

大型常压锥顶贮罐的设计

以工程实例为依据，论述国内以往较少采用的大型梁柱式支承锥顶贮罐的结构，介绍了国内外相关设计标准，给出了贮罐的典型结构－斜椽，横梁和立柱的计算公式，并用Excel电子表格编制了计算书。     

Ruthenium tetroxide catalysed oxidation of Illinois No. 6 coal: The formation of volatile monocarboxylic acids

Ruthenium tetroxide selectively oxidizes activated aromatic compounds under mild conditions and has been used for the catalytic oxidation of several different coals. The quantities of the volatile monocarboxylic acids with 2–6 carbon atoms have been determined by an isotope dilution technique. The amount of ethanoic acid ranges from 1 to 3mol/100C and the quantities of propanoic acid, and butanoic acid exceed 0.1 mol/100C. Methylpropanoic, pentanoic, 2-methylbutanoic, 3-methylbutanoicand hexanoic acid are formed in lesser amounts. The outcome of the experiment depends upon whether or not the coal has been extracted prior to oxidation. The results for Illinois No. 6 coal expressed in moles of ethanoic acid produced/l00C illustrate this feature: raw whole coal, 1.9; coal extracted by the method of Hayatsu and co-workers, 1.0. Dehydrogenation with benzoquinone prior to oxidation increases the yield of ethanoic acid to $\text{sol1.5mol}\text{100C.}$ The amounts of ethanoic acid obtained from the other extracted coals are 1.0 for Texas lignite, 1.2 for Rawhide subbituminous, 3.4 for Pittsburgh No. 8, 3.3 for a higher ranking bituminous coal (PSOC 726) and 0.7 for an anthracite (PSOC872). The results obtained in this study are compared with related information concerning the distribution of alkyl groups within coal by other methods.     

钛酸铝材料性能及合成工艺

着重介绍了钛酸铝（Al2TiO3）陶瓷的结构、性能和合成工艺，并对今后发展趋势提出了基本观点。     

Intramolecular vs intermolecular formation of bityrosine upon photoreaction of poly(l-tyrosine) in dilute aqueous solution

Summary The molecular weight dependence of the rate of the formation of bityrosine upon irradiation of poly(L-tyrosine) at 300 nm has been investigated in dilute aqueous solution, pH 12. The samples studied were the monodisperse monomer, dimer, trimer, and hexamer, as well as two polydisperse polymers with average degrees of polymerization of 10² and 10³. The reaction is predominantly intermolecular in the monodisperse oligomers, but it is predominantly intramolecular in the two polymers. The intramolecular reaction in the polymers involves phenolic rings on monomers i and i+j, with j>5. The steric restraints imposed by the backbone of the chain make it unlikely that two rings will approach one another with the appropriate geometry for reaction if j<5.     

民办高校外籍教师的绩效管理研究

探讨民办高校外籍教师绩效管理应遵循制度化、科学化、精细化、人文化等原则:民办高校外籍教师绩效管理的内容应包括制度管理、教学管理、生活管理及绩效考核等方面.     

荔浦县旅游形象定位研究

根据荔浦县的自然地理、文化传统和社会心理方面的特点,认为荔浦旅游形象的核心要素是以溶洞为代表的旅游资源和以荔浦芋为代表的民俗文化,因此荔浦县的旅游形象可提炼为"洞绝天下,‘芋'(誉)满神州".     

高校和谐平安校园建设研究

围绕创建和谐平安校园、实现学校新一轮发展的战略目标,必须要建立健全的思想政治工作机制,完善沟通机制,健全保障机制,构建公平公正的法治环境。     

普通高校学生自主学习能力探究

自主学习是主体教育思想在教学领域的反映,其本意是学生由他主学习转向自主学习。学生自主学习,是符合学生学习的本质和特点的,也是培养未来具有自主性、创造性、创新性人才的根本要求,本文提出实现学生自主学习,应注意激发学生兴趣,运用多种手段提高教学质量,多让学生动手动脑,提高学生的自主学习能力,才能真正突出学生的主体地位。     

女性博客：公共领域的性别再塑或重塑

传播学的受众分类为女性博客提供了一个存在的界定,然而,这一明显为女性定制的公共领域空间中,女性的自主性别形象塑造是否具有网络的充分自主与自由？是对传统媒体女性刻板印象的再塑,还是对其的重复与巩固？笔者拟就此进行调研基础上的分析。