石墨炉内石墨探针表面上的原子化机理研究 III. 铬的原子化机理

本文利用探针原子化技术, 研究了普通管式石墨炉内石墨探针表面上铬化合物的原子化过程。X射线衍射分析(XRD)、俄歇电子能谱(AES)、化学分析光电子能谱分析(ESCA)与石墨炉原子吸收光谱(GFAAS)测量的综合结果表明, 铬化合物在灰化阶段即可转化为稳定的碳化物, 最后由碳化物的热分解生成气态铬原子。     

NANOMECHANICAL MAPPING OF CARBON BLACK REINFORCED NATURAL RUBBER BY ATOMIC FORCE MICROSCOPY

Atomic force microscopy （AFM） has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young＇s modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young＇s modulus distribution image together with reconstructed real topographic image. Then we were able to recognize three regions; rubber matrix, carbon black （or bound rubber） and intermediate regions. Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space.     

新型锂离子电池阳极材料Li2.7Mg0.3N的研究

以氮化锂和镁金属为原料,制备了Li2.7Mg0.3N样品,利用XRD、原子吸收、库仑滴定等方法研究了锂离子电池阳极材料Li2.7Mg0.3N的组成、结构及电化学性能。样品Li2.7Mg0.3N经成分分析组成为Li2.74Mg0.26N;其结构为四方晶系,晶胞参数a=0.388nm,c=0.547nm;比容量为1695(mA.h)/g,嵌入量x最大可达2.5276,室温时锂离子嵌入Li2.7Mg0.3N的嵌入自由能为-397.51kJ/mol,锂离子在Li2.7Mg0.3N中的化学扩散系数为5.90×10^-^11～7.23×10^-^10cm^2/s,并得到一系列热力学和动力学参数。     

电化学方法分析铅阳极膜的相组成

本文提出使用线性电位扫描和电位衰退定性和定量分析铅在4.5mol·dm^-^3H2SO4(30℃)中形成的阳极膜的相组成并与现场X射线衍射, 原子吸收光谱, 阳极溶出等法比较。结果表明电位扫描伏安曲线的峰电位和电位扫描至峰电位左右时电极开路后, 所得的稳定电位可用于阳极膜相组成的定性分析, 电位扫描伏安电线电流峰的面积可用于阴极膜相组成的定量分析。本文的阳极膜由PbO·PbSO4, PbO2和PbOn(2>n>1)组成, 以PbO·PbSO4为主要成份。     

Topographical observation of silane-treated inorganic surface using atomic force microscopy

The topography of the silane-treated layer on an inorganic surface was observed using an atomic force microscope. For this purpose, the cleaved mica plate was treated with some silane coupling agent at varying conditions. The silanes having aminopropyl or methacryloxypropyl group as organofunctional groups with di- or trialkoxyl structures were used. Three different solvents for silane solution — 2-propanol, 2-propanol/water mixture and water — were used. The pH of the aqueous solution was controlled. As a result, the most suitable solvent and pH in order to obtain smooth silane layer was clarified. The solubility of silane molecules in the solution, the wettability of silane molecule onto inorganic surface, and prevention of the mutual condensation of silane molecules in the solution were found to be important parameters for this purpose.     

Interaction between two solid surfaces across PDMS: influence of chain length and end group

Forces between solid surfaces across polymer melts are poorly understood despite their importance for adhesion and composite materials. Using an atomic force microscope (AFM) this force was measured for poly(dimethyl siloxane) (PDMS) on silicon oxide. The influence of molecular weight (4.0–40 kDa) was studied. Forces are attractive for low and repulsive for high molecular weight. In addition, changing the terminal methyl group for a hydroxyl group leads to an increased probability of bridging.     

Models and approximations for the momentum distribution in nuclear matter

As a step toward development of a framework for phenomenological analysis of nuclear momentum distributions in terms of dynamical interparticle correlations, the momentum distribution n(k) of symmetrical nuclear matter described by a Jastrow wave function is studied within a variety of approximation schemes. In particular, two simple low-cluster-order approximations are proposed, one of which may be readily adapted to finite nuclei. For two choices of pair correlations tailored respectively to soft and moderately stiff repulsive cores, the results based on these approximations compare favorably with the standards set by Fermi-hypernetted-chain evaluation and (for the kinetic energy) by Monte Carlo integration — even at densities somewhat beyond the empirical equilibrium density of nuclear matter. The crucial role played by the Jastrow wound parameter, as a determinant of the overall behavior of n(k), emerges clearly from these calculations.     

OBSERVATION OF DNA PARTIAL DENATURATION BY ATOMIC FORCE MICROSCOPY

Atomic force microscopy was used to investigate the DNA-cetyltrimethylammonium bromide (CTAB) complexes adsorbed on highly ordered pyrolytic graphite (HOPG). These complexes, at low concentrations, can automatically spread out on the surface of HOPG. The DNA-CTAB complexes display a typically extended structure rather than a globular structure. Partially denaturated DNA produced by binding CTAB to DNA is directly observed by AFM with high resolution. The three-dimensional resolution of partially denaturated DNA obtained by AFM is not available by any other technique at present.     

流动注射在线吸附预富集原子光谱联用技术在痕量 (形态)分析中的应用

深入系统地讨论了以编结反应器(KR)为吸附介质的流动注射(FI)在线预富集分离与原子光(质)谱联用技术及其在环境和生物样品中(超)痕量元素(形态)分析中的应用。与常用的FI在线C18微柱预富体系相比,KR体系不需填料作吸附剂、反压低、可用较大样品流速以补偿其富集效率低的缺点,并且使用寿命几乎无限长。KR吸附体系具有经济、简便和易操作等优点,是替代常用的FI在线C18微柱预富集的比较理想的体系。     

Zeeman原子吸收光谱分析法中谱线轮廓的研究I.原子发射谱线.原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射轮廓. 吸收线轮廓和Zeeman分裂后的吸收线轮廓, 并建立了在原子吸收光谱法中三者轮廓间的重叠关系