Application of a 2-beam model for improving the structure factors from precession electron diffraction intensities

A 2-beam model is used to simulate precession electron diffraction (PED) intensities. It is shown that this model can be inverted with minimal knowledge of the underlying crystal structure, permitting structure factor amplitudes to be deduced directly from measured intensities within the 2-beam approximation. This approach may be used in conjunction with direct methods to obtain correct, kinematically interpretable structure indications for data sets from relatively thin crystals (less than approximately 400A), and an experimental example based on (Ga,In)(2)SnO(5) is presented. The failure of this approach at large thickness is illustrated by an additional data set for MFI zeolite. The 2-beam approximation provides a simple model for PED intensities, and inversion using this model shows advantages over a kinematical approximation. It is however too rough approximation to be of general use and ultimately it is to be hoped that more accurate models with similar ease of use can be derived to treat PED data.     

An electron microscope for the aberration-corrected era

Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown.     

Handling partial truth on type-2 similarity-based reasoning

Representation and manipulation of the vague concepts of partially true knowledge in the development of machine intelligence is a wide and challenging field of study. How to extract of approximate facts from vague and partially true statements has drawn significant attention from researchers in the fuzzy information processing. Furthermore, handling uncertainty from this incomplete information has its own necessity. This study theoretically examines a formal method for representing and manipulating partially true knowledge. This method is based on the similarity measure of type-2 fuzzy sets, which are directly used to handle rule uncertainties that type-1 fuzzy sets cannot. The proposed type-2 similarity-based reasoning method is theoretically defined and discussed herein, and the reasoning results are applied to show the usefulness with the comparison of the general fuzzy sets.     

Cowoven polypropylene/glass composites with polypropylene + polymer liquid crystal interlayers: Dynamic mechanical and thermal analysis

Simultaneous macroscopic and molecular reinforcement of polypropylene with glass fibers and Polymer Liquid Crystals (PLCs) is evaluated. Interlayers of polypropylene (PP) + poly(ethylene terephthalate) /0.6 p-hydroxybenzoic acid PLC blends are introduced between the cowoven polypropylene + glass fiber plies. Analysis was conducted using Dynamic Mechanical Thermal Analysis (DMTA), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). The results indicate that low fractions of PLC material in the composite have dual benefits of increased rigidity and toughness. The crystallization kinetics are influenced by the dual nucleating effects of both reinforcing agents. A decrease in crystallinity is associated with increasing PLC presence. Degradation kinetics of the composites demonstrate only one kinetic step in contrast to the interlayers alone.     

绿色高效三合一精练剂NC-601的研制和应用

以烷基糖苷为非离子表面活性剂主体组份，适当添加各种助剂，开发了无磷、无熔基酚聚氧乙烯醚类的绿色环保型三合一高效精练剂NC－601，探讨了它在纯棉织物上高效短流程前处理（冷轧零和碱氧一浴）工艺。     

"2006亚洲食品配料及技术展览会"的亮点天然食品配料区

在当今的食品工业领域内，天然，健康的食品配料已越来越多地受到人们的欢迎，天然配料包括天然食品添加剂和天然健康食品添加剂。全球食品工业的产品质量正在日益提高。在食品配料市场上有着一股主导趋势，这股趋势引领着一部分的健康食品发展，这就促成天然食品配料的产生。为了迎合这样的一股行业趋势，“2006亚洲食品配料及技术展览会”的主办单位，欧洲博闻公司将在2006展会现场引入天然食品配料专区.     

A quantitative analysis of the cone-angle dependence in precession electron diffraction

Precession electron diffraction (PED) is a technique which is gaining increasing interest due to its ease of use and reduction of the dynamical scattering problem in electron diffraction. To further investigate the usefulness of this technique, we have performed a systematic study of the effect of precession angle on the mineral andalusite where the semiangle was varied from 6.5 to 32 mrad in five discrete steps. The purpose of this study was to determine the optimal conditions for the amelioration of kinematically forbidden reflections, and the measurement of valence charge density. We show that the intensities of kinematically forbidden reflections decay exponentially as the precession semiangle () is increased. We have also determined that charge density effects are best observed at moderately low angles (6.5–13 mrad) even though PED patterns become more kinematical in nature as the precession angle is increased further.     

Prospects for aberration corrected electron precession

Recent developments in aberration control in the TEM have yielded a tremendous enhancement of direct imaging capabilities for studying atomic structures. However, aberration correction also has substantial benefits for achieving ultra-resolution in the TEM through reciprocal space techniques. Several tools are available that allow very accurate detection of the electron distribution in surfaces allowing precise atomic-scale characterization through statistical inversion techniques from diffraction data. The precession technique now appears to extend this capability to the bulk. This article covers some of the progress in this area and details requirements for a next-generation analytical diffraction instrument. An analysis of the contributions offered by aberration correction for precision electron precession is included.