Information technology support in the chemical process design life cycle

Information technology has been becoming increasingly important in all areas of engineering during the last few years. Much of the progress achieved in chemical engineering would not have been possible without the enabling methods and tools provided by information technology. This trend will continue in the future but most likely with a considerably wider scope. While individual software tools and services have been in focus until recently, their integration into engineering work processes is an emerging and challenging area of research and development. This contribution attempts to highlight state of the art and future trends in supporting the activities during the life cycle of a chemical process by means of information technology. Emphasis will be largely on the process and plant design process rather than on procurement, manufacturing, and distribution of materials in the supply chain.     

CNC机床结构动态设计方法研究

提出机床结构动态设计基本原则。以某数控弧齿铣齿机为研究对象,应用相关的动态设计原则,通过变量化设计与有限元分析,对该机床进行结构动态设计。结果表明,应用该方法设计的机床结构具有良好的动静态特性。     

数控机床交流伺服系统的复合控制研究

针对常规P-P与PPI控制存在的问题，提出了在数控机床交流伺服系统中，采用带速度和加速度作为前馈控制，模糊自校正PID控制作为位置反馈控制的复合控制器，实验证明可以显著提高控制系统的控制精度，大大降低跟踪误差，具有较强的鲁棒性。     

Marcia K. Johnson: 2006 Award for Distinguished Scientific Contributions.

Presents the citation to Marcia K. Johnson, who received the Award for Distinguished Scientific Contributions "for raising and illuminating fundamental questions about the cognitive and neural processes that constitute the subjective experience of mental life." A brief profile and a selected bibliography, as well as Johnson's award address, entitled Memory and Reality (see record 2006-21079-028), accompany the citation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

蜂胶乙醇浸提液在牛乳制品保鲜中的效果研究

研究了不同浓度的蜂胶对鲜奶的保鲜作用，以及蜂胶对酸奶中酵母菌的抑制作用；同时选择常用化学防腐剂苯甲酸钠作为对照。研究表明，蜂胶能延长鲜奶的保存期。灭菌前加入质量分数为0．1％蜂胶可将鲜奶保存期延长一倍多。0．1％蜂胶可以显著抑制酸奶中酵母的增殖，既可明显延长保存期，又不影响乳制品的自身品质。蜂胶可以代替苯甲酸钠，具有天然保鲜防腐效果。     

Service life planning and performance requirements

Service life planning comprises a model for the determination of a reasonable expected service life for buildings and components, and it establishes a routine for the assessment of design alternatives. A design option is considered reasonable when it meets or exceeds performance requirements over time that have been drawn up specifically for the specific project. Due to this assessment reference, there is a very evident link to the concept of performance-based building. Any stakeholder involved in the value chain or in the design process of the building, as well as regulators and building users, can express performance requirements. Identified requirements, both in relevance and in quality, will vary with the stakeholder and his/her perspective of interest. As building sector manufacturers develop most products with reference to standards rather than with reference to specific requirements, there is no direct link from user requirements to the product design. Instead, the building designer has the responsibility to ensure performance requirements are met by the performance of products integrated into the design. As these design decisions also have to be made at the material and component level, a performance-based building would benefit from an established rationale that enables the communication of performance requirements across the relevant system levels in the relevant design processes. A path for the connection of the established concepts of service life planning and performance-based building is presented. The aim is to identify key elements that need to be developed for the successful linkage of performance-based building with service life planning.     

论老年教育的地位、作用和发展方向

老年教育在社会中具有重要的地位和作用。它是终身教育的重要组成部分,是社会发展的客观需要,是解决老龄问题的重要途径和方法。探讨了随着社会经济的发展和老龄化社会进程的加快,在21世纪老年教育的发展方向。     

High temperature low cycle fatigue

Fatigue at high temperature is a complex phenomenon as it is influenced by a number of time-dependent processes which become important at elevated temperatures. These processes include creep, oxidation, phase instabilities and dynamic strain ageing (DSA), acting either independently or synergistically influence fatigue behaviour, often lowering the fatigue life. Current design approaches employ linear summation of fatigue and creep damage with suitable factors on permissible damage to take care of uncertainties in interaction between cyclic and time-dependent processes. It is, therefore, important to develop a deeper understanding of the processes that occur during high temperature fatigue so that realistic life predictions could be made. Results on the high temperature fatigue behaviour of austenitic stainless steels, ferritic steels and nickel base alloys are presented here. The important mechanisms of interaction of high temperature time-dependent processes with fatigue under various conditions are discussed in detail. Emphasis is placed on cyclic stress response, fatigue life, deformation substructure and fracture behaviour. This is followed by a review of important life prediction techniques under combined creep-fatigue loading conditions. Life prediction techniques considered here include linear damage summation, strain range partitioning, ductility exhaustion approach, frequency modified and frequency separation methods, techniques based on hysteresis energy and damage rate models, and methods based on crack-cavitation interation models.     

AI paradigms

The aim of this paper is comparative analysis of most important AI paradigms. An AI paradigm is defined as the pair composed by a concept of intelligence and a methodology in which intelligent computer systems are developed and operated. Three paradigms, the behaviourist paradigm, the agent paradigm, and the artificial life paradigm are discussed.     

高炉长寿技术的新发展

高炉长寿是目前国内外炼铁界关注的主要课题。在此介绍了国内外高炉的长寿状况，高炉长寿技术的最新发展趋势以及应用情况。