加氢脱氮催化剂中硫化钼结构的表征

众所周知,重油加氢脱氮(HDN)所用Mo-Ni/Al2O3催化剂需经预硫化后始有显著的活性,关于硫化的条件工业上已较成熟,但在持续反应过程中硫化催化剂的结构与活性间的关系则很复杂,如硫化钼的价态和结构、金属组分和担体间的相互作用、反应条件及原料对催化剂组分的影响,以及硫化态催化剂中MoS2结晶的形貌等都可以引起催化剂活性本质的变化.     

光谱实验室的建设和管理

阐述冶金、铸造等行业用于金属成分分析的直读发射光谱仪实验室的建设和管理。从仪器的调研、选型，实验室选址，基础设施设备的准备，仪器的安装、调试、验收、日常分析，实验室管理等几个方面，分别作了介绍。     

铌酸锂单晶光纤包层研究

通过镁离子内扩散铌酸锂单晶光纤，以改变晶纤表层的折射率，首次在国内实现了沿不同轴向生长、不同掺杂的铌酸锂单晶光纤的芯－包层波导结构。通过匹配扩散温度、扩散时间、ＭｇＯ膜厚等扩散参数及选择合适的晶纤直径，实现了晶纤具有阶跃和抛物折射率分布的包层，并对包层晶纤的模式特性进行了观察，得到低次模传输。     

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响王卫华，贝建中，王智峰，王身国（中国科学院化学研究所北京１０００８０）关键词聚己内酯聚醚嵌段共聚物，共混物，电子能谱，表面性质，药物释放行为聚己内醋（ＰＣＬ）具有优良的药物通透性和生物相容...     

Progress on phthalocyanine-conjugated Ag and Au nanoparticles: Synthesis,characterization, and photo-physicochemical properties

Phthalocyanine (Pc) complexes are an important class of dyes with numerous (e.g., biological, photophysical, and analytical) applications. Among the methods used to improve the properties of these complexes, one should mention the introduction of different substituents, variation of the central metal ion, ligand exchange, and conjugation to nanomaterials (e.g., carbon-based nanomaterials and metal nanoparticles (NPs)). This work briefly reviews Pc complex conjugation to Ag and Au NPs, highlights the different NP shapes, and discusses the diversity of conjugation approaches. Moreover, the use of UV–Vis spectroscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and Fourier transform infrared spectroscopy to characterize Pc-NP hybrids is summarized. The effect of conjugation on Pc photo-physicochemical properties (fluorescence, singlet oxygen generation, triplet state formation, and optical limiting behavior) is discussed, and future perspectives for the synthesis and applications of new hybrids are provided.     

Multi-turn time-of-flight mass spectrometers with electrostatic sectors

The mass resolution of a time-of-flight (TOF) mass spectrometer is directly proportional to its total flight pathlength. Multi-turn or multi-passage ion optical geometries are necessary to obtain fight distances of sufficient length within reasonable size limitations. We have investigated ion optics for a multi-turn TOF mass spectrometer with electrostatic sectors. The concept of 'perfect' focusing conditions is introduced. Furthermore, a new type of multi-turn TOF mass spectrometer, the MULTUM Linear plus, was developed. It consists of four cylindrical electric sectors and 28 electric quadrupole lenses. It has a vacuum chamber 60 x 70 x 20 cm in size. Mass resolution is demonstrated to increase according to the number of ion cycles. A mass resolution of 350 000 (m/z = 28, FWHM) was achieved after 501.5 cycles. The MULTUM Linear plus analyzer is not simple, however; 28 electric quadrupole lenses are used. In order to reduce the number of ion optical parts, an improved multi-turn TOF mass spectrometer, the MULTUM II, consisting of only four toroidal electric sectors, was also developed. The possibility of tandem mass spectrometric applications using multi-turn TOF mass spectrometers is also discussed.     

Characterization of thermo-oxidative stability of polymer optical fibers using chemiluminescence technique

The thermo-oxidative stability of commercially available polymer optical fibers (POFs) and their components (cores and claddings) was investigated. All the bare POFs (core and cladding only) studied here were based on poly(methyl methacrylate) (PMMA) core. The fibers were exposed to 100 °C/low humidity for about 4200 h. Chemiluminescence (CL) technique was applied to investigate the thermo-oxidative stability and for measuring the transmission loss during exposure a prototype device called multiplexer was used. POFs exhibited variation in thermo-oxidative stability although they possessed identical core material PMMA. This was due to difference in the chemical compositions of claddings. Claddings were more susceptible to the thermo-oxidative degradation compared to cores. The thermo-oxidative degradation of both the cladding and the core was found in POFs as a result of climatic exposure. POFs showed an early drop-off followed by a slow decline of transmission. The early drop-off of transmission was attributed to physical changes like thermal expansion and the slow decline of transmission to chemical changes like oxidative degradation of POFs. A good linear relationship between optical transmission stability and thermo-oxidative stability of POFs was established from these studies.     

量化方法研究分子结BEMP和TEMP的电子输运特性

通过结合杂化密度泛函和前线轨道理论与弹性散射格林函数方法研究了BE- MP(benzene-1,4-di-ethynyl-4-mercaptophenyl)和TEMP(thiophene-2,5-di-ethynyl-4- mercaptophenyl)两分子结的输运性质。基于杂化密度泛函方法计算两扩展分子电子结构的基础上,计算了两分子的输运性质．计算结果显示:电流增加来源于电极和分子轨道的共振;电导曲线呈现出平台特征．在此基础上从扩展分子A(Au-BEMP-Au)中间的苯环的旋转而引起电流减小的角度解释了负微分电阻现象．     

Structural and Chemical Analysis of Materials with High Spatial Resolution

 An understanding of the correlation between microstructures and properties of materials require the characterization of the material on many different length scales. Often the properties depend primarily on the atomistics of defects, such as dislocations and interfaces. The different techniques of transmission electron microscopy allow the characterization of the structure and of the chemical composition of materials with high spatial resolution to the atomic level: high resolution transmission electron microscopy allows the determination of the position of the columns of atoms (ions) with high accuracy. The accuracy which can be achieved in these measurements depends not only on the instrumentation but also on the quality of the transmitted specimen and on the scattering power of the atoms (ions) present in the analyzed column. The chemical composition can be revealed from investigations by analytical microscopy which includes energy dispersive X-ray spectroscopy, mainly quantitatively applied for heavy elements, and electron energy-loss spectroscopy. Furthermore, the energy-loss near-edge structure of EELS data results in information on the local band structure of unoccupied states of the excited atoms and, therefore, on bonding. A quantitative evaluation of convergent beam electron diffraction results in information on the electron charge density distribution of the bulk (defect-free) material. The different techniques are described and applied to different problems in materials science. It will be shown that nearly atomic resolution can be achieved in high resolution electron microscopy and in analytical electron microscopy. Recent developments in electron microscopy instrumentation will result in atomic resolution in the foreseeable future.