Dispersion-strengthening effect of Cu-based Mn, Al, and Zn rich alloys

In this systematic study, dispersion-strengthening effect of the Cu–25.91Mn (wt.%), Cu–26.62Mn–8.99Al (wt.%), Cu–22.17Mn–12.32Zn (wt.%) ingot alloys have been investigated. Samples were homogenized at a high fixed temperature in different periods and cooled with different cooling rates. After processes, microanalysis of the samples were interpreted by using scanning electron microscope (SEM) and weight percentages of the elements of the occurrence phases in the samples obtained by using electron dispersion spectroscopy (EDS) technique. Additionally, some characteristic properties of the heat treated samples with different conditions of Cu–Mn, Cu–Mn–Al, Cu–Mn–Zn ingot alloys were also discussed.     

Practical phase identification by convergent beam electron diffraction

The purpose of this article is to present a practical guide to the identification of phases in the analytical electron microscope with the aid of convergent beam electron diffraction. There is included a step-by-step approach to phase analysis, from the possible choices of the form of the specimen through how to explore reciprocal space in order to perform a full phase identification, either by symmetry analysis or by simple comparison of a pattern observed in the microscope with a previously recorded pattern (fingerprinting). There is a strong emphasis on practical hints and useful shortcuts.     

现代X光电子能谱(XPS)分析技术

现代电子能谱仪有3个主要功能:单色XPS(Mono XPS)、小面积XPS(SAXPS)和成像XPS(iXPS),被认为是光电子能谱仪发展方向。本文介绍这3个功能突出的特点及在材料微分析方面的实际应用。     

Freeze-fracturing at low temperatures: I. A device for fracturing biological specimens at 77–10 K under high vacuum

Standard freeze-etching or freeze-cleaving is performed at 173 K in a vacuum of 133 μPa or at 77 K under liquid nitrogen with subsequent transfer of the specimen into a vacuum chamber. It has been suggested that the frequent poor resolution of morphological details, the poor complementarity of innermembrane protein particles and the semi-crystalline substructures in biomembranes are caused by structural distortion or plastic deformation due to sheer forces which occur even at 77 K during fracturing or cleaving. In addition, water contamination and radiant heat damage occurring during replication introduce artefacts to the structural record. These artefacts could be avoided or reduced by lowering the temperature at which fracturing or cleaving and shadowing is carried out, to about 10 K. Therefore, a device for cleaving biological specimens at 15–10 K under high vacuum was constructed. To allow the use of existing equipment, the device was built into a standard Balzers 301 vacuum unit, where the specimen transfer is done via an airlock system which allows hoar frost contamination free transport of the specimen holder onto the specimen table. To reduce or prevent the condensation of water and other residual gases in the vacuum onto the freshly cleaved specimen surface at 10 K, the specimen is surrounded by two cooled surfaces of 6 and 20 K. All condensable gases outside those shielding shrouds will condense on these surfaces before reaching the specimen. This makes it possible to work at a high vacuum of 3 μPa outside the cooled shrouds, which can be reached with standard turbomolecular pumps. The actual vacuum within the cooled shrouds is estimated to be approximately 13 nPa. Residual gas analysis before and during replication reveals equal conditions to ultra high vacuum systems. An analysis of the yeast cell paracrystalline plasmalemma structure shows that the topographic resolution of the crystalline arrays has been improved by working at 12 K. However, plastic deformation still occurs under these conditions. This observation points to the possibility that what is described as plastic deformation, for at least some membrane proteins, may be a loss of resilience at low temperatures.     

Investigation on the polymer particle growth in ethylene polymerization with PS beads supported rac-Ph2Si(Ind)2ZrCl2 catalyst

The mechanism of polyethylene particle growth was investigated using poly(styrene-co-divinylbenzene) (PS beads) supported rac-Ph₂Si(Ind)₂ZrCl₂ catalyst. From the analysis of the resulting polyethylene particles by SEM (scanning electron microscopy) and EPMA (electron probe microanalysis), it was found that the active species are located on the surface layer of catalyst particles and that the catalytic species are uniformly distributed throughout the polymer particles, whereas the cores of PS beads, which lack a potential active species, were not disintegrated during polymerization. These results suggest that the PS beads supported catalyst also follows the fragmentation and replication process as frequently observed with the MgCl₂ supported Ziegler–Natta catalysts.     

Microanalysis for microelectronics

Microanalytical methods are powerful tools for the diagnosis and elimination of failures in materials and components in microelectronics. Because of the very small structure dimensions, especially methods with extremely high spatial resolution were used for characterization of microstructure details or for identification and quantitative estimation of chemical composition in very small areas or very thin layers. In this publication a short overview of the most important microanalytical methods is given and particle beam methods are described in more detail. Their principles are explained and their performance is described with examples of analytic problems of development and production of microelectronic components.     

Acoustic beam position monitor for microanalysis of particles in the 10 nm range in a TEM-SCAN system

This paper describes the principle and use of a simple equipment which makes it possible to keep the electron beam in the centre of a small particle analysed by X-ray microanalysis in a STEM system. A deviation from the correct beam position introduced by drift or other deficiencies is monitored by an audible change in a sound frequency and corrected for by a convenient manual operation.     

三维原子探针研制新进展

本文介绍世界上新型三维原子探针技术研究的最新发展。具体介绍内容包括原理、工作模式、在材料研究中的初步应用结果。最后对其前景作了展望。     

场发射俄歇电子能谱显微分析

场发射俄歇电子能谱的显微分析是一项新的分析技术,可对微尺度样品进行点、线、面的元素组分及元素化学态分析。本文简要介绍这项新技术的功能原理和在微电子器件检测等方面的具体应用。     

微观分析仿真的建模与在养老保险制度改革中的应用（续）

作者介绍了微观分析仿真模型的基本思路和建模方法,并以烟台职工养老保险制度改革模型为应用实例,建立了人口状态模型和政策模型,提出了面对事件的仿真方法,从而将数据库系统作为仿真试验的平台。