Software in the new millennium: a virtual roundtable

What will software look like in the future? To answer this question, we conducted a survey of our editorial and industrial advisory boards, as well as a few outsiders. We constructed a set of 13 questions that we thought reflected the original query. We then circulated these questions to our boards, with a request to respond to the questions, or be extend them with additional are questions as appropriate. The answers were far ranging and sometimes surprising.     

A Multivariate T2 Control Chart for Skewed Populations Using Weighted Standard Deviations

This paper proposes a heuristic method of constructing multivariate T² control charts for skewed populations based on ‘weighted standard deviations’, obtained by decomposing the standard deviation into upper and lower deviations according to the direction and degree of skewness. The proposed method adjusts the variance–covariance matrix of quality characteristics and modifies the ellipsoidal probability density function contour of the multivariate normal distribution to a shape similar to that of the skewed distribution. False alarm rates and out‐of‐control average run lengths of the proposed control chart are compared with those of the standard control chart for multivariate lognormal, Weibull and gamma distributions, and the results show that considerable improvement over the standard method can be achieved when the distribution is skewed. Copyright © 2003 John Wiley & Sons, Ltd.     

Internet的定价研究

Internet作为一个半公共物品被广泛应用于许多领域，一直面临如何有效对Internet进行定价的问题．提出了Internet定价中存在的问题，分析了定价机制，并尝试性地给出了一个定价模型．Internet定价是一个动态过程，定价依赖于使用者的类型、使用时间和网上阻塞情况。     

Calculating the elastic moduli of steel-fiber reinforced concrete using a dedicated empirical formula

The equivalent inclusion method (EIM) is adopted to study the characteristics of the equivalent material properties of steel-fiber reinforced concrete as a function of the volume fraction and the length to diameter ratio of the fibers. It is found that the equivalent material moduli of concrete reinforce with randomly orientated and distributed fibers are insensitive to the length to diameter ratio of the steel fibers. A set of empirical formulae is then proposed for the purposes of engineering applications. The proposed empirical model can simplify the calculation of the equivalent material moduli. Verifications of the proposed empirical formulae with the EIM model and with experimental data are performed with two examples. The first is a compression test. The second is 4 point bending test. The empirical formulae, based on the equivalent inclusion method proposed in this study, represent an alternative means of quickly calculating the effective elastic modulus of steel-fiber reinforced concrete materials.     

有限元方法用于预报轮胎的侧偏特性

分析了影响轮胎胎侧偏特性的理论模型分析精度低的几个因素,采用有限元分析手段弥补理论模型缺陷,建立了能够考虑轮胎实际结构的侧偏特性分析模型,不但提高了分析精度,而且能够对多种型号轮胎进行侧偏特性预报。计算结果表明轮胎侧偏特性与试验数据吻合较好,说明此方法预报轮胎侧偏特性的有效性,并为轮胎的结构优化及改进侧偏特性提供了一种有效的分析方法。     

Study on Compound Effect of Bonded Magnets

The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnetic properties and ferrite content was clearly revealed by the physical relation in the magnetic powders.     

Effect of H_2 dilution on the structure and properties of nc-CrC/a-C:H coatings deposited by a hybrid beams system

Nanocomposite Cr C/hydrogenated amorphous carbon(nc-CrC/a-C:H) coatings were deposited by a hybrid beams system comprised of a hollow cathode ion source and a cathodic arc ion-plating unit with varying H_2 flow rates. The influences of H_2 flow rates on the morphologies, microstructures, and properties of the coatings were systematically studied. The morphologies and microstructures of the coatings were characterized by SEM, AFM, XPS, Raman spectroscopy, GIXRD, and HRTEM. The mechanical and tribological properties were measured by a nano-indenter, scratch tester, and ball-ondisk tribometer. The wear tracks were evaluated using 3D profilometer, optical microscope, and EDS analysis. It has been found that a moderate H_2 flow rate can effectively smooth the surface, enlarge the fraction of a sp~3 bond, and improve the properties. The coating exhibits the highest hardness and elastic modulus at the H_2 flow rate of 40 sccm. A superior combination of adhesion strength,friction coefficient, and wear resistance can be achieved at the H_2 flow rate of 80 sccm.     

变压器行业采用IEC标准综述

论述了做好IEC工作的意义 ,较全面地介绍了变压器行业采用IEC标准现状和IEC标准制、修订动态 ,提出了采用IEC标准建议     

配电自动化系统分析及改进方案

配电网是电力网络中直接面向电力用户的一个环节,是检测供电可靠性的重要部分。配电自动化的广泛应用,为调度运行控制能力、故障处理能力和配网检修能力的提高奠定了基础,也对社会保电活动等提供可信的技术手段和技术措施,极大减少停电次数和停电时间。本文结合西咸新区供电公司成立后的配电网规划,对配电网的发展现状、存在的问题进行分析,并从主站信息和馈电线路方面提出了切实有效的改进方案。     

高校思想政治理论课多媒体案例教学法探究

高校思想政治理论课多媒体案例教学法是在信息技术迅猛发展的背景下出现的一种全新的教学方法。通过分析思想政治理论课多媒体案例教学法的优势,并对其应用的特点和注意事项进行了比较详细的举例分析,充分证明了多媒体案例教学法应用于高校思想政治理论课教学必将起到事半功倍的效果。