Stabilization of Pt nanoparticles by single stranded DNA and the binary assembly of Au and Pt nanoparticles without hybridization

The non-specific interaction between single stranded DNA (ssDNA) and 12 nm Pt nanoparticles is investigated in this work. The data show a strong and non-specific interaction between the two which can be exploited for the stabilization of Pt nanoparticles in aqueous solutions. Based on the experimental findings, a non-hybridization based protocol to assemble 17 nm Au and Pt nanoparticles (12 nm cubic and 3.6 nm spherical) by single-stranded DNA was developed. Transmission electron microscopy (TEM) and UV–visible spectroscopy confirmed that Au and Pt nanoparticles could be assembled by the non-specific interaction in an orderly manner. The experimental results also caution against the potential pitfalls in using DNA melting point analysis to infer metal nanoparticle assembly by DNA hybridization.     

Spontaneous Vesicle Formation in Mixed Aqueous Solution of Poly-tailed Cationic and Anionic Surfactants

Spontaneous vesicles from the mixed queous solution of poly-talied cationic surfactant PTA and anionic surfactant AOT are firstly obtained.Vesicle formation and characterizations are demonstrated by negative-staining TEM and dynamic light scattering.A monodisperse vesicle system is obtained with a polydispersity of 0.082.Ultrasonication can promote the vesicle formation,Mechanism of vesicle formation is discussed from the viewpoint of molecular interaction.     

Synthesis, Characterization and Structure of 3d Metal Nitrate Complexes with 1,8-Naphthyridine-N-Oxide

The complexes of 3d metal(Cr, Mn, Fe, Co, Ni, Cu, Zn) nitrates with 1 , 8-naphthyridine-N-oxide (NAPYO) were synthesized. The melting points and solubilities of the new complexes were determined and all the complexes were characterized by elemental analyses, IR spectra, UV spectra and molar conductance. The structures of both nickel complex and copper complex were determined by X-ray single crystal diffraction analyses.     

企业营销道德测试与评价系统研究

介绍了利用现代化管理技术，构建企业营销道德评价指标体系的方法和模式；利用计算机建立企业营销道德测试与评价系统的目标、总体结构以及开发实施方法．     

Growth of poly(methyl methacrylate) particles in three-component cationic microemulsions

Polymerization of methyl methacrylate (MMA) has been studied in ternary microemulsions which were stabilized by tetradecyltrimethylammonium bromide (TTAB) or stearyltrimethylammonium chloride (STAC). The sizes of MMA-swollen polymer particles (R_h) increased continuously during polymerization. This is in contrast to that of the styrene system, where R_h increased very rapidly to a maximum and then decreased continuously towards a constant value. The continuous growth of PMMA particles at 60°C are discussed. The stability of PMMA latexes increased with increasing the hydrophobic chain length of the cationic surfactant used. Traces of the coagulations of PMMA particles in the TTAB system can be seen from TEM. © 1995 John Wiley & Sons, Inc.     

物理学和天文学

历史上，物理学和天文学的发展是密切联系的。它们在整个现代科学的发展和技术的发达上起到了先锋的作用。物理学的基本规律和天文学提供的广亵的实验室构成了理想的科学发展的基础。20世纪的一系列科学上的重要突破正是这种优良结合的产物。今天，天文学和物理学又共同面对着更新的前测问题，并一道酝酿着新的科学上的重大进展。它们所取得的每一个进展也必然伴随着技术的创新和提高，也不断更新着人类的认识和文明。     

抗多径的线性合并SFH／MFSK系统在短波信道中的性能

在线性合并接收机的基础上，引入了抗多径干扰的措施，并分析了这类新型接收机在存在部分边带干扰的多径瑞利衰落信道中的性能，着重研究了多径加权因子对系统性能的影响．研究结果表明，最佳加权因子ω＊与多径干扰强度，分集重数，调制阶数和信道热噪声有关。对多径合适地加权可明显地改善系统的性能，在分集和编码相结合时，能使Ｐｂ下降２～３个数量级同时本文还研究了分集重数Ｌ和调制阶数Ｍ对系统性能的影响．     

ON A PROBLEM OF WHITNEY

In 1944 H.Whitney raised a problem:Let M be an open smooth n-manifold.Doesthere exist an imbedding of M into R~(2n) with no limit point set?Introducing a sort of Morsenumber for open manifolds and using Whitney trick,the author gives a direct proof ofthe affirmative answer to it.