Na(THF)2(μ2-η5-Cp)(η5,η5,η1-Cp3Yb)(THF)]n: The synthesis and X-ray structure of an anionic organolanthanidepolymer formed via self-assembly

Cp2Yb·2THF reacts with CpNa in 1：1 molar ratio in THF at 40℃ for 2 h, and the in situ generated anionic divalent complex NaYbCp3（THF）n reacts further with an excess of CpH at 40℃ for 48h, after work-up, affording the trivalent anionic ytterbium complex[Na（THF）2（μ2-η^5-Cp） （η^5, η^5,η^1-Cp3Yb）（THF）]n：（1） by oxidation reaction of Cp2Yb with CpH. Crystal structure determination reveals that complex 1 has one-dimension polymeric chains of distinct Na（THF）2（μ2-η^5-Cp） （η^5, η^5,η^1-Cp3Yb）（THF） units, which were formed by the coordination of the bridging Cp ligand with Cp3Yb＇THF and Na（THF）2 in η^5,η^5 mode via self-assembly.     

Effect of density of hydrogen-bonding donor on hydrogen-bonded multilayer buildup

The effect of density of hydrogen-bonding donor （HBD） on the formation of layer-by-layer assemblies of poly（4-vinylpyridine） and poly（4-vinylphenol） was investigated. For this purpose, a series of ethyl-substituted poly（4-vinylphenol） （EsPVPhf） with variable ethyl substitute percentage was synthesized by grafting the phenol moiety along the poly（4-vinylphenol） backbone with 1-bromoethane. UV-vis spectroscopy revealed a uniform deposition process of the hydrogen-bonded multilayer consisting of poly（4- vinylpyridine） （PVPy） and EsPVPhf with variable density of HBD. Notably, it was found that increasing the HBD density of EsPVPhf resulted in a marked decrease of both amount of polymers adsorbed and film thickness, which should be related to the EsPVPhf conformation change from coiled state to extended conformation in ethanol solution. Compared with the effect of charge density in polyelectrolyte multUayer, however, there does not exist a critical density of HBD in our case of hydrogen-bonded multilayer assembly. In addition, surface structures of PVPy/EsPVPhf multilayer films also can be tailored controllably by adjusting HBD density of EsPVPhf. As a result, a new method for tuning the structure of hydrogen-bonding-directed multilayer films was developed.     

影响萘高效减水剂与普通硅酸盐水泥适应性的关键因素

通过试验分析和探讨了影响萘高效减水剂与普通硅酸盐水泥适应性的关键因素，并进一步阐明了使用萘系高效减水剂生产高性能混凝土时，应用本试验结果认真选择水泥的重要性。     

Progress in non-viral gene delivery systems fabricated via supramolecular assembly

Gene delivery systems are one of key issues that limit the development of gene therapy. The novel non-viral gene delivery systems fabricated via supramolecular assembly have begun to show increasing promising and applications in gene therapy due to its suitable nanometric size,controllable structure and excellent biocompatibility. In this review, the fundamental and recent progress of non-viral gene supramolecular assembly is reviewed. Artificial viruses the future direction of non-viral gene delivery systems are also described.     

关于图运算的测地数

对于图G(或有向图D)内的任意两点u和v,u-v测地线是指在u和v之间(或从u到v)的最短路.I(u;v)表示位于u-v测地线上所有点的集合,对于SV(G)(或V(D)),I(S)表示所有I(u,v)的并,这里u,v∈S.G(或D)的测地数g(G)(或g(D))是使I(S)=V(G)(或I(S)=V(D))的点集S的最小基数.G的下测地数g-(G)=min狖g(D):D是G的定向图狚,G的上测地数g+(G)=max狖g(D):D是G的定向图狚.对于两个图G和H,u∈V(G)和v∈V(H),在u和v之间加一条边,然后再收缩这条边uv所得的图,记为GuHv.本文主要研究图GuHv的测地数和上(下)测地数.     

篮球运动训练对西安市中学生心理控制点发展影响的研究

本文运用文献资料法、问卷调查法和数理统计法,对西安市中学生篮球运动员和普通中学生进行了抽样研究得出:西安市中学生篮球运动员和普通中学生的心理控制点之间存在着显著差异;不同训练年限、不同技术等级的篮球运动员心理控制点也分别呈显著差异。一方面它为教练员、体育教师和运动员的归因训练提供了理论依据,另一方面也开拓了运动员的心理训练范畴。     

论专利实施许可下被许可人的诉讼资格

专利权是一种专有权,可是专利权人可以通过专利实施许可合同赋予被许可人专利实施权。但是,当出现第三人侵犯专利实施许可合同项下的专利权时,被许可人能否提起诉讼在我国法律上存在缺失,使得这成为一个急需解决的问题。本文从专利实施许可三种方式的特征及其区别来探讨此问题。     

内联框架(Iframework)在网页设计中的一种应用

通过分析普通框架网页在制作和使用过程中的利弊,提出了合理且巧妙使用内联框架的解决方法,使得设计出来的网页既有普通框架网页的优势,又较好地克服了普通框架网页的不足,并且还使网站的性能和专业化程度都得到了较大的提高,在实际应用中具有较强的可操作性.     

基于普通数码影像快速绘制等高线方法研究

利用普通数码相机采集立体像对,通过直接线性变换(DLT)方法,对所采集的立体像对进行分析、解求,进而求取立体像对内的地表三维空间坐标,利用求得的地表三维空间坐标组建三角网(TIN),从而在TIN的基础之上绘制等高线。     

数据采掘中的可视化技术和方法

主要介绍了几种目前常用的可视化数据采掘技术，以及它们的含义、技术特点和适用范围；同时描述了一个集成多种可视化数据采掘技术的系统工具——VisDB系统，并对其性能进行了评价；最后，通过一个商业POS的数据采掘应用实例，说明可视化数据采掘技术对分析和检索大型数据库是非常有用的。