集成产品数据管理软件PDM Works

当主流立体建模软件在上个世纪90年代中期面世的时候,它显著提高了时间和成本的效率,使得工程师工作效率更高.以前总是埋头在2D设计图中的设计团队现在能够在几个小时内完成设计,而且点击几下鼠标就能完成修改.更好的视图让他们能够从一开始就正确地设计一个产品,最大限度减少了后期装配的问题.他们还可以自动创建设计图,并且重复利用以前的设计,缩短新产品的设计时间.     

Performance of HF signal injection techniques for zero-low-frequency vector control of induction Machines under sensorless conditions

A number of HF signal injection techniques have been proposed for the sensorless zero-low-frequency control of induction machines (IMs). This paper reviews these methods and experimentally investigates their performance under true sensorless conditions for a standard cage IM with closed rotor slots. Implementation techniques covering hybrid methods, saliency decoupling, and saliency orientation are discussed. The paper concludes that, while HF techniques can outperform observer-based methods at low frequencies, the robust performance required for industrial application still presents a research challenge.     

A Strategy for Managing Office Automation Projects

Experience indicates that a change in technology must be accompanied by user education. It is not the technology alone, but the way in which the technology is planned, designed, and implemented that determines the success of change. Employees must not only understand the applications of office technologies but also deal with the organizational impact of change. Successful development of office automation systems must involve users, management, and systems professionals in the planning, design, and implementation of change.     

Three‐Dimensional Nanofabrication by Block Copolymer Self‐Assembly

Thin films of block copolymers are widely seen as enablers for nanoscale fabrication of semiconductor devices, membranes, and other structures, taking advantage of microphase separation to produce well‐organized nanostructures with periods of a few nm and above. However, the inherently three‐dimensional structure of block copolymer microdomains could enable them to make 3D devices and structures directly, which could lead to efficient fabrication of complex heterogeneous structures. This article reviews recent progress in developing 3D nanofabrication processes based on block copolymers.     

Simulating novel gas turbine conditions for materials assessment: cascade design and operation

Integrated gasification combined cycles can incorporate pre-combustion carbon capture. High-H₂ syngas produces high H₂O levels after combustion, potentially accelerating gas turbine component damage. Determining materials systems’ suitability for this novel environment requires exposures in representative environments. Thus, an existing 0.7?MW burner rig was modified to generate the combustion environment and incorporate a cascade of 15 air-cooled turbine blades. Computational fluid dynamic calculations using blade dimensions and flow requirements supported the cascade design and determined blade placement within the gas flow. Trials of the modified unit have shown that a simulated combusted H₂-rich syngas composition was generated at gas temperatures ≤1440°C. A 1000?h exposure has been carried out with thermal barrier coated blades to demonstrate the operation of the unit.

This paper is part of a thematic issue on the 9th International Charles Parsons Turbine and Generator Conference. All papers have been revised and extended before publication in Materials Science and Technology.     

Plant food supplement (PFS) market structure in EC Member States, methods and techniques for the assessment of individual PFS intake

The popularity of herbal products, especially plant food supplements (PFS) and herbal medicine is on the rise in Europe and other parts of the world, with increased use in the general population as well as among specific subgroups encompassing children, women or those suffering from diseases such as cancer. The aim of this paper is to examine the PFS market structures in European Community (EC) Member States as well as to examine issues addressing methodologies and consumption data relating to PFS use in Europe. A revision of recent reports on market data, trends and main distribution channels, in addition an example of the consumption of PFS in Spain, is presented. An overview of the methods and administration techniques used to assess individual food consumption as a starting point, including their uses and limitations, as well as some examples of studies that collect Food Supplement (FS) information, including herbal/botanical/plant-derived products are also discussed. Additionally, the intake estimation process of food nutrients is described and used to propose the PFS ingredients intake estimation process. Nationally representative PFS consumption data is scarce in Europe. The majority of studies have been conducted in Scandinavia and the UK. However the heterogeneity of definitions, study design and objectives make it difficult to compare results and extrapolate conclusions.