挣值法核心要素及其在公路工程项目管理中的应用

挣值法是一种能全面衡量和反映项目进展状况的科学管理方法。它通过其核心要素,把项目的成本和进度有效的结合成一个整体进行分析,从而实现对项目目标的监控及评价。但挣值法在实际应用时还存在一定的缺陷,应在挣值管理的同时,提高项目信息技术含量,同关键路径法结合,实现公路工程项目质量、进度和成本的集成管理。     

Nonvolatile memory devices based on organic field-effect transistors

Among the many possible device configurations for organic memory devices,organic field-effect transistor (OFET) memory is an emerging technology with the potential to realize lightweight,low-cost,flexible charge storage media.In this feature article,the recent progress in the classes of OFET-based memory,including floating gate OFET memory,polymer electret OFET memory,ferroelectric OFET memory and several other kinds of OFET memories with unique configurations,are introduced.Finally,the prospects and problems of OFETs memory are discussed.     

Advancements in organic nonvolatile memory devices

As one of the most promising candidates for next generation storage media, organic memory devices have aroused worldwide research interest in both academia and industry. In recent years, organic memories have experienced rapid progress. We review the development of organic resistive switching memories in terms of structure, characteristics, materials used, and integration. Some basic concepts are discussed, as well as the obstacles hindering the development and possible commercialization of organic memory d...     

Surface nanostructures orienting self-protection of an orthodontic nickel-titanium shape memory alloys wire

Shape memory alloys (SMA) have been applied to a wide variety of applications in a number of different fields such as aeronautical applications, sensors/actuators, medical sciences as well as orthodontics. It is a hot topic to enhance the anti-corrosion ability of orthodontic wires for clinical applications. In this letter, a very nice fractal structure, micro-domains with identical nanometer sized grooves, was ob- tained on the surfaces of the orthodontic wires with an oxygen plasma and acid corrosion. The concave parts of the grooves were dominated by titanium and convex parts were the same as the bulk wires. The micro-nano fractal structure generated a hydrophobic surface with the largest contact angle to water being about 157°. The titanium dominated nanolayer and the hydrophobicity of the surface resulted in jointly the great improvement of the anti-corrosion ability of the orthodontic wires. Because the fractal structures of the wires were formed automatically when they immersed in acidic environment, hence, the self-protection of the oxygen plasma-treated orthodontic wires in acidic environment indicates their potential applications in orthodontics, and should be also inspirable for other applications of SMA materials.