Crystallographic electron microscopy

We present a family of techniques for the transmission electron microscope that generate surface zone-axis patterns. These patterns display the variation of the diffracted-beam intensity as a function of the angle of the incident electrons. The conditions of the experiments are those of reflection high-energy electron diffraction at near grazing incidence. The techniques are: surface convergent-beam diffraction, a surface analogue of the Tanaka method and a modified double-rocking scheme. Experimental results are presented for diffraction from surfaces of MgO and MoS₂. We anticipate that surface zone-axis patterns (surface ZAPs) will become established as an important tool for surface characterization, especially when used in conjunction with high-resolution surface imaging and surface energy loss spectroscopy; surface ZAPs may be expected to play, in surface analysis, a role analogous to that played by convergent-beam diffraction in normal transmission electron microscopy.     

The effect of the textile industry dye bath additive EDTMPA on colour removal characteristics by ozone oxidation.

In this study, the effects of the phosphonic acid based sequestering agent EDTMPA used in the textile dye baths on colour and organic matter removal by ozone oxidation was experimentally investigated. Procion Navy HEXL dyestuff that has been commonly used for the reactive dyeing of cellulose fibers was selected as the model component. The organic matter oxidation by ozone was determined to obey the pseudo-first order kinetics as they are treated singly or in combination. COD removal rates obtained from pseudo-first order reaction kinetics showed that oxidation of Navy HEXL alone (0.0947 L/min) was faster than that of EDTMPA (0.0171 L/min) and EDTMPA with dye (0.0155 L/min) at pH 3.0. It was also found that reaction rates of single EDTMPA removal and EDTMPA and dye mixture removal increased as the reaction pH was increased from 3.0 to 10.5.     

广泛应用机器人技术是提高连铸安全性的重要步骤

1前言及历史背景 为避免钢水造成燃烧或破碎引起对人体的可能伤害,必须对连铸平台的平面布置进行分析.     

Reliability of structures in high dimensions, part I: algorithms and applications

The present paper is concerned with the estimation of structural reliability when a large number of random variables is present. A sampling technique which uses lines in order to probe the failure domain, is presented. The latter is employed in conjunction with a stepwise procedure which makes use of Markov Chains. The resulting algorithm exhibits accelerated convergence.     

Possibilities and extension of XRD material response analysis in failure research for the advanced evaluation of the damage level of Hertzian loaded components

Due to clearly distinguishable damage symptoms, it is differentiated between the surface and sub‐surface failure mode of rolling bearings. Material states red out by X‐ray diffraction (XRD) residual stress measurements point to a variety of loading conditions especially at raceway surfaces that are associated with several competing failure mechanisms. The corresponding lifetime reduction can range from the lower fatigue strength region to material ratcheting in extreme cases. Relevant position of the microstructural changes and nature of the failure mechanisms are characterized. The time alteration of the XRD material parameters measured at or near the surface and at the depth of the maximum equivalent stress correlates, in a different manner, with the statistical parameter of the 10 % bearing life. Both failure modes are illustrated by concrete examples. Contaminated lubricant and boundary lubrication, which represent practically important surface‐induced failures, are discussed in more detail. Gray staining, i.e. shallow pitting, often occurs without distinct indication of global material aging by means of XRD characteristics. Here, scanning electron microscopy observations and electron microprobe analyses point to corrosion fatigue as acting surface failure mechanism. The interaction between material and lubricant under complex loading regimes particularly of mixed friction and corrosion opens further failure research areas in the field of tribology.     

Mesa and planar SiGe-HBTs on MBE-wafers

SiGe-HBTs have the potential for outstanding analog and digital or mixed-signal high frequency circuits widely based on standard Si technology. Here we review on MBE grown transistors and circuits. Processes and results of a research-like SiGe HBT and two possible production relevant HBT versions are presented. The high frequency results with f_max and f_T up to 120 GHz and a minimum noise figure of 0.9 dB at 10 GHz demonstrate the advantage of using MBE samples with steep and high base doping and high germanium contents. A comparison to the concept of reported low doped, low germanium and triangular profiled SiGe base layers, realized by UHV-CVD, is given. In addition, some circuit demonstrators of SiGe-ICs will be presented.