质量管理(下)——美国与日本的质量管理

在美国,一些最大的电子公司已开始让生产工人参与提高产品质量和可靠性的工作。它们正在仿效日本近二十年中发展起来的管理技术,并使这些技术建立在美国的社会科学理论基础之上。这种新引进的设想不     

十个值得一赌的科技趋势

(续上期 )ｅＢａｙ去年夏天 ,一位记者向因特网专家基姆·克拉克(ＪｉｍＣｌａｒｋ)请教几个因特网公司的投资要诀。他的推荐 :抛掉ＡＯＬ ,买进微软和Ａｍａｚｏｎ ,保留雅虎。但当他说到ｅＢａｙ时 ,他停顿了。“我不知道 ,”他说。不要在意克拉克的预测和 2 0 0 0年大多数其他投资者一样大错特错 ,他对于ｅＢａｙ的评论是很值得注意的。ｅＢａｙ的 2 2 0 0万用户与宗教信徒一样虔诚 ,但投资者们从来也不知道如何对待这家公司。不错 ,ｅ Ｂａｙ从它面向公众这天就开始盈利 ,但它的远景总是令人怀疑。还记得那个想拍卖他一个肾的人吗 ?在繁…     

Elaboration of AlSi10Mg casting alloys using directional solidification processing

The effects of pulling velocity on the solidification behavior and microstructural parameters of AlSi10Mg alloys prepared in a Bridgman-type directional solidification furnace were investigated. The microstructure, particularly the secondary dendritic arm spacing (SDAS), and the Brinell hardness (BH) of the solidified AlSi10Mg alloys were characterized for samples with cylindrical shapes and different conicities (θ=0°, 5°, and 10°). Microstructural studies revealed an increased density of α-Al phase dendrites and a decreased interdendritic distance with increasing pulling velocity. The dendrites were found to be preferentially oriented along the pulling direction for low pulling velocities. For larger pulling velocities, the dendrites grew first in the cooling direction but then broke as others nucleated and coarsened. The HB values of the solidified samples increased as the pulling velocity increased. In regard to sample conicity, smaller dendrites were observed for an apex angle of θ=5°, resulting in the largest HB value. This result was interpreted in terms of the favorable orientation of the dendrite along the pulling direction.     

太阳能固体吸附式制冰系统长期性能研究（Ⅱ）：——不良 …

对有不良气体存在下系统的制冷热力学循环进行了分析,建立了不良气体存在时,系统循环ＣＯＰ的计算模型,利用所建ＣＯＰ模型对系统的长期性能变化进行了分析了分析并对系统寿命进行了评估,在此基础上提出了解决系统长期性能下降问题的简便面有效的途径。     

磁力涡旋

新的发现表明磁力是宇宙中和引力一样基本的现象一九八四年夏,天文学家们用新墨西哥州的VLA射电望远镜观察了远离银河系平面的弧形纤维状星云。这些看来是由一个磁场结合在一起的螺旋状物形成了一个直径约600光年的磁力涡旋。这一本身就具有重大意义的发现,为磁力涡旋在宇宙演化过程中起着重要作用的说法提供了新的证据。这一观点直到最近才引起了人们的重大关注。洛斯阿拉莫斯国家实验室的等离子物     

Fibre Distribution in Friction-spun Yarns

IntroductionIt is reasonable to expect the fibre distribution in across-section of a blended yarn to have an influence on theperfor mance of the yarn. This is particularly so if one ofthe components has specific inherent property of interest .In this paper ,the specific property is fire retardancy (FR)in conex fibre . The objective is establishing the fibredistribution resulting fromvarious input sliver arrangementin friction spinning .The distribution of fibres in blended yarns has beenthes…     

Site effects on earthquake ground motion based on microtremor measurements for metropolitan Beijing

A campaign of microtremor measurements was conducted in summer 2007 for assessing local site effects of seismic strong ground motion in metropolitan Beijing. Using the measurements from over 600 sites with approximately 1―2 km spacing covering the entire area inside Beijing’s 5th Beltway, we present the analysis results in the form of contours of the predominant resonant frequency, the thick- ness of the uppermost soft sediments, and the ground motion amplification factor. The microtremor- derived soft sedi...     

重症监护病人脑电数据的自动聚类分析（英文）

癫痫性发作、持续状态及痫样节律性活动是常见的病理性脑部放电状态,通常会在急性脑损伤患者的脑电图(EEG)中表现出来。完成此类病理性波形的有效标记,是进一步诊断与治疗相关疾病的重要前提。为辅助神经内科专家对不同病理波形进行快速标记,文中提出了一种全新的辅助检测标记系统。该系统分别采用特征提取、PCA降维和LE映射可视化等技术,实现EEG中同质模式簇的自动检测。所提方法对哈佛医学院/麻省总医院中10例ICU患者的长时程连续脑电图进行了系统分析。数值实验结果表明,海量脑电数据能够被有效地自动聚类为多种ICU典型标准波形,而且仅通过观测类中心及若干同类成员就能够达到有效标记的目标。同时,LE可视化结果也进一步证实了"发作间期-发作期"连续统假设是成立的。     

清洁能源研究领域科学计量分析(2005-2009)加拿大-美国的国际合作

加拿大清洁能源研发合作推广工作组当前正重新评价加拿大与美国之间的合作伙伴关系,旨在为清洁能源研发长期合作计划筛选出合适的科学领域作为清洁能源对话行动方案框架的一部分.根据该科学计量分析结果,工作组将进一步探索清洁能源研发领域以及三个子领域(新一代生物燃料、清洁能源车辆与绿色建筑)的科学产出与合作前景.科学计量结果表明,...