利用DPN技术直接构建磁性纳米图形

在纳米尺度下构建有序的磁性模板和图形是当前的研究热点之一 [1,2 ] .这种模板在生物样品的分离[1] 、磁电子学研究和信息存储 [2 ] 等领域具有重要意义 .目前 ,光刻 [3] 、微触点印刷 [4 ] 和自组装 [5] 等多项技术已被用来构建各种纳米模板 .1 999年 ,美国西北大学 Mirkin小组 [6 ]发明的 Dip- pen纳米刻蚀技术 (简称 DPN技术 )更在可控组装方面显示出巨大优越性 .这项技术是在一定驱动力作用下 ,使吸附在原子力显微镜 ( AFM)针尖上的分子“墨水”逐渐转移到基底表面上 ,实现纳米模板的可控构建 .与传统技术相比 ,DPN技术可在纳米尺…     

配体形状对多吡啶铜(Ⅱ)配合物与DNA作用的影响

合成了一系列含有平面配体的Cu(Ⅱ)多吡啶配合物[Cu(IP)₂]²⁺、[Cu(PIP)₂]²⁺、[Cu(DPPZ)₂]²⁺和[Cu(HPIP)₂]²⁺，用吸收光谱、CD光谱和粘度等方法研究了这些配合物与小牛胸腺DNA的作用。结果表明配体上的取代基及配体的平面性对这些四面体配合物与DNA的结合强弱产生一定的影响。[Cu(DPPZ)₂]²⁺与DNA的结合较强，而[Cu(HPIP)₂]²⁺与DNA的结合较弱。CD光谱显示配合物[Cu(DPPZ)₂]²⁺、[Cu(PIP)₂]²⁺和[Cu(HPIP)₂]²⁺的加入会导致DNA的CD光谱减弱。而[Cu(IP)₂]²⁺的加入则会使DNA的CD光谱增强。同时，[Cu(IP)₂]²⁺与DNA结合后，还会引起一定程度的DNA构型转换，即DNA从B型转换成Z型。     

钴(Ⅱ)-5-取代邻菲罗啉-α-氨基酸三元配合物的稳定性研究

本文在25.0±0.1℃,I=0.1mol·dm^-3KNO₃存在下,采用pH法测得了5-取代邻菲罗啉的质子化常数以及钴(Ⅱ)与5-取代邻菲罗啉、α-氨基酸的二元、三元配合物的稳定常数。结果表明三元配合物的稳定性与5-取代邻菲罗啉的质子化常数、取代基常数均存在直线自由能关系。并用三元配合物稳定性的表征值logK_M、△logK,讨论了三元配合物的稳定性,发现钴(Ⅱ)与配体5-取代邻菲罗啉之间也存在着d-p反馈π键。该π健的强度对三元配合物稳定性有着显著影响。     

On the copolymerization of acrylates in the modified microemulsion process

Copolymerization of methyl methacrylate, methyl acrylate, butyl methacrylate, and butyl acrylate in turn was performed in the modified microemulsion polymerization process, i.e., continuous addition of monomer to a preemulsified system. It was found that the particle size of the copolymer microlatex did not change distinctly with the monomer composition. The estimation of emulsifier coverage on the microlatex particles indicated that the process switched from a traditional microemulsion to a normal seeded emulsion polymerization very soon after monomer dropping began. Therefore, a longer dropping time is needed to produce a microlatex with narrow dispersed particle size. Besides, in the modified microemulsion polymerization less emulsifier is needed to produce a stable microlatex. This behavior is related to the mechanism of normal seeded emulsion polymerization during monomer dropping.     

Coating Carbon Nanotubes with Europium Oxide

Carbon nanotubes (CNTS) coating with europium oxide by a simple method is reported in this letter for the first time. The CNTS were refluxed in a solution of nitric acid containing europium nitrate, and the pH value was subsequently ajusted with ammonia solution. At last, the mixture was filtered and annealed. The TEM micrograph showed that the CNTS were covered with a uniform thin layer with thickness of about 15 nm. The XRD results revealed that the CNTS were coated with europium oxide.     

活性炭纤维对氙的动态吸附性能研究

采用动态吸附实验装置，研究了吸附温度、原料气浓度和原料气流量对活性炭纤维动态吸附氙性能的影响。结果表明：在低温条件下（≤273K)，随着温度的升高，活性炭纤维对氙的平衡吸附量明显下降／同时，活性炭纤维对氙的平衡吸附量分别随着原料气浓度及原料气流量的增大而增大。     

A Sterically Hindered Zirconocene Complex (1,2-Ph2C5H3)2ZrCl2:Synthesis, Structure and Properties as Olefin Polymerization Catalyst

SinceKaminskyeIal.discoveredthehighlyactivezirconocenedich1oride/methyl-aluminoxane(MAO)catalyticsystemforolefinpolymerization',intensiveresearchworkhasbeenfocusedondevelopingnewgroup4metal1ocenecatalystsforimprovingcatalystactivitiesandpolymerproperties"'.Inthedevelopmentofnewmetallocenecatalystsystems,liganddesignandmodificationhaveplayedanimportantrole.lthasbeenknownthatevenminormodificationofagivenligandframeworkcouldresultinsignificantchangesincatalystactivitiesandpolymerproperties'.Int…     

滇紫草及露蕊滇紫草的氨基酸和元素分析

为分析滇紫草及露蕊滇紫草中的氨基酸和元素含量，将样品用酸处理后，采用氨基酸分析仪及电感耦合等离子体发射光谱仪进行了测定。结果表明，两种紫草含有18种氨基酸及14种元素。可见滇紫草及露蕊滇紫草问氨基酸和元素含量没有重大的差异。     

四君子汤和四物汤微量元素含量研究

通过了解中药“四君子汤”和“四物汤”中微量元素含量的异同,研讨了微量元素和中医“气血”理论之间的关系。实验表明,“四君子汤”和“四物汤”在微量元素的含量方面,有一定的类同和差异。该现象同中医的“气血”理论有非常相像的地方。同时发现中药中的微量元素在煎煮过程中,并不是同想象的一样匀速进入药液,而是不同的元素在不同的时间段不同的批次进入药液,这也提示中药煎法理论有一定依据。由于目前做的实验还少,本实验留下很多问题和疑点,值得进一步做有关的实验和研究。