The influence of publication delays on three ISI indicators

Summary Based on the transform function model of the observed citing process, the analytical expression of the age distribution of citations is deduced, and it is theoretically proved that the peak value of the citation distribution curve would fall and shift backward along with increasing the average publication delay and the peak age has a direct proportion relation with the pure delay and would be prolonged along with increasing the delay or decreasing the aging rate. The influence of the average publication delay on three ISI indicators impact factor, immediacy index and cited half-life are studied; in one subject discipline, the bigger the delay, the lower the three indicators of journals. Using the sensitivity theory, sensitivity formulae of the three indicators to publication delay parameters are deduced and it is found that responses of these indicators to changes of publication delays are different according to different time constant of the aging process; The faster the aging rate of a discipline literature is, the worse the influence of publication delays on the indicators of journals in the discipline.     

Analysis of superalloy turbine blade tip cracking during service

High Pressure Turbine (HPT) first stage blade is the most important rotational components of aero-engine. It operates at high temperature and under conditions of extreme environmental attack such as oxidation and corrosion, is especially subjected to degradation by oxidation, corrosion and wear. During the service of aero-engine, the HPT first stage blades made of c 6 y nickel-based superalloy suffer from increasing blade tip cracks after hundreds of hours service. This significantly affects the whole engine function and, of course, safety of the aircraft. In this paper, the premature tip cracking of the HPT first stage blade is investigated. The research result shows that turbine blade tip is initially damaged by rubbing and corrosion over a period time, premature cracking of blade tip is caused by a combination mechanism of environment and thermal stress. During turbine blade maintenance and refurbishment, coating of both oxidation-resistance and abrasion-resistance should be applied in blade squealer tip to counteract the problem.     

Enhanced photoelectrochemical current response of titania nanotube array

Self-organized and highly-ordered TiO₂ nanotube array with disjunctive wall-hole structure has been synthesized from titanium foil by potentiostatic–galvanostatic anodization process. The morphology and microstructure of the TiO₂ layer depend greatly on the electrolyzing parameters and electrolyte components. TiO₂ formation mechanism by anodization oxidation is discussed. The crystallized TiO₂/Ti nanotube electrode exhibited a significant enhancement of photoelectrochemical current response in comparison with micrometer-sized TiO₂/Ti multiporous electrode. Such kind of TiO₂ nanotube will have many potential applications in various areas as an outstanding photoelectrochemical material.     

有限差分法计算HF分子的振动能级和光谱

本文用有限差分法计算了HF分子的振动能级并且把计算的结果用切比雪夫法进行拟合得到了HF的光谱项,将所得结果与黄整等人的用时域有限差分法计算所的结果和实验值进行了比较。     

企业标准化工作现状与发展

介绍了如何构筑企业标准化工作平台，提高企业的核心竞争力及企业标准化工作的现状。阐述了大力推进企业标准化工作与走一条简捷、优化、高效、科学的企业发展之路的关系。     

电子对抗装备战术指标体系构建方法

考虑电子对抗的作战特点，遵循体系构建原则，依据作战目标特性，以作战规模为依据，把电子对抗装备战术指标划分为战略、战役、战术三个层次，并把作战规模作为一级指标的划分依据，选择作战用途和装备指标性质作为二级指标的划分依据，装备的具体作战能力和环境适应能力作为三级以下指标划分依据。     

GPS电子地图坐标转换算法研究

GPS车载导航系统现在已经运用得十分广泛,然而GPS采用的是WGS-84坐标系,目前我国的各类地图均采用54北京坐标或是80西安坐标,两者的差距可达0～120m.要使用各类电子导航装置就需要把WGS-84坐标转换到54北京坐标系下,并和电子地图中的像素点对应起来.本文主要介绍一种坐标转换算法,并且通过实测检验,证实算法效果良好.     

Selective wet etching of p-GaN for efficient GaN-based light-emitting diodes

The selective wet etching of a p-GaN layer by using a solution of KOH in ethylene glycol (KE) was studied to enhance the optical and electrical performance of the GaN-based light-emitting diodes (LEDs). The surface of the p-GaN, which was selectively etched in the KE solution, showed hexagonal-shaped etch pits. The light-output power of etched LEDs was improved by 29.4% compared to that of the nonetched LED. This improvement was attributed to the increase in the probability of photons to escape due to the increased surface area of textured surface and the reduction in contact resistance of the ohmic layer resulting from the increased contact area and hole concentration on the textured p-GaN. The reverse leakage current of the LED was also greatly decreased due to the surface passivation and the removal of defective regions from the p-GaN.     

实例推理在光学加工参数优化中的研究与应用

为解决光学加工CCOS模型固有的缺陷,将实例推理CBR引入到光学加工中.给出了CBR中光学加工实例的具体表达形式,并对CBR系统中的关键技术一一匹配算法,即相似度的求解进行详细的说明,在此基础上,建立了CBR原型系统.实践证明,该系统运行良好.     

基于位图的点集表面表示及其渲染

提出了一种基于位图的点集表面表示形式：先对点集表面进行参数化，然后在参数域上进行曲面重构和重采样得到基于二维数组的点集表面表示。采用了切空间对齐的方法得到点集表面的参数坐标。该方法能寻找出点集代表的流型所在的二维参数空间，并存参数化过程中较好地保留了原曲面的尺度信息。位图形式表示点集表面具有数据结构简单和便于随机访问的优点。提出了基于位图表示形式的点渲染方法，该方法采用双线性插值来实现视角依赖的点集表面的重采样，解决了点渲染中采样点不足的问题。