双应力恒加试验Weibull分布型产品置信可靠性评估模型

为了有效快速评估高可靠性长寿命产品在正常应力条件下的可靠性,提出了一种双应力恒加试验Weibull分布型产品置信可靠性评估模型。首先,采用加速寿命试验(accelerated life test,ALT)技术,建立广义Eyring-Weibull可靠性模型,假定试验各应力水平组合下Weibull分布的形状参数相同,且尺度参数与各应力水平组合间呈对数线性关系。其次,给出了Weibull分布定时截尾双应力恒加试验的极大似然估计(maximum likelihood estimation,MLE)方法、与似然函数相关的Fisher信息矩阵以及模型参数的渐近协方差矩阵,构造了模型参数和一些可靠性指标的渐近置信区间。最后,通过仿真算例证明了所提方法的可行性。     

Periodical oscillating interface in directional growth under shear flow

Liquid-solid interface morphological evolution of SCN-2wt%H2O alloy was investigated in the presence of shear flow. It has been found that shear flow strikingly enhances the stability of planar interface at lower pulling rates. In the intermediate range of pulling rate, the interface experiences periodical oscillating ＂planar-cellular＂ and ＂cellular-dendritic＂ growth patterns. The formation of oscillating growth modes can be explained by two reasons： （i） The stabilizing effect induced by shear flow competes with the growing destabilizing effect by the increase of pulling rate, which provides the driving force for morphological evolution; and （ii） the establishment of stable solute field at the liquid-solid interface needs a period of time, leading to the result that the interface evolution can not stay stable at the equilibrium state. However, as the puling rate becomes higher, it plays more and more important roles in pattern selection and dendritic growth forms.     

Solar-driven high temperature radiant cooling

Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller’s COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%. According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion. Supported by the National Natural Science Foundation of China (Grant No. 50876064)     

基于数据流优化的BPEL流程分割方法

BPEL描述的业务流程在跨组织的企业应用集成与协作中扮演着重要角色.目前BPEL流程主要采用集中式的执行方式,但是集中式执行的BPEL流程性能不高并且不能满足动态流程管理的需求.提出了一种基于数据流优化的BPEL流程分割方法,以支持BPEL流程的分散化执行.BPEL流程经过变换被表示成PFG图,提出数据流方程对PFG图进行数据流分析,扩展复制传播算法优化PFG图的数据流.最后按照流程中的角色分割BPEL流程.实验数据表明优化分割后的业务流程的吞吐率、响应时间等方面的性能有较大提高.     

试析目前企业工人的地位和作用

目前,企业中工人的地位得不到重视,逐渐成为社会的弱势群体,笔者根据目前工人在企业中的状况作一简单阐述。     

A novel mechanism controls anther opening and closing in Paris polyphylla var. Yunnanensis

The phenomena of anther opening and closing in Paris polyphylla var. yunnanensis (Franch) Hand.-Mazz were described in detail, and the effects of ecological factors on those phenomena related to anther opening, closing and the fly-pollination mechanism were discussed. Anthers of P. polyphylla var. yunnanensis open in the morning and close in the evening every day during an over 20 days’ period of anthesis. Light was detected as the main factor controlling this daily anther opening and closing. Anther opening can be reversed in response to rain and re-opens when rain stops. Relative humidity (RH) has a slight effect on anther opening and closing. Flower spans can be prolonged under laboratory conditions. This novel behavior of anther is likely to be a mechanism to enhance the male fitness in this species, of which has no inherited structure to protect pollen from the perianth.     

"五笔字型"汉字录入技术的教学初探

文章就如何在中等职业类学校中"五笔"课程教学进行了初步探索,从5个方面论述了"五笔"课程的教学方法与手段,着重培养学生理论和实际相结合的能力.     

粉煤灰机制砂混凝土在G208线夏店互通立交桥中的应用

结合工程实际分析了粉煤灰、机制砂掺入水泥混凝土后对混凝土特性的影响,为粉煤灰和机制砂在公路桥梁中的大量利用提供参考。     

区域控制器（PLC）在高速公路隧道中的应用分析

文章简要介绍了当前中国隧道监控系统的构成,在此基础上分析了控制系统的整体解决方案以及其区域控制器（PLC）及网络的选型,同时,以贵州玉凯高速公路项目为例,详细分析了单隧道和隧道群的具体解决方案,最后分析了隧道监控系统的改进与发展。     

知识经济时代的图书馆人力资源管理创新

通过分析图书馆人力资源的现状及存在的问题,提出了图书馆人力资源管理的新理念,认为图书馆在人力资源管理方面应以人为本,引入竞争机制、激励机制等。