化工泵机械密封选用及失效探讨

机械密封失效可能会引发安全事故,文章从机械密封的结构和组成入手,对机械密封原理和泄漏点进行了深入的分析,并提出机械密封失效预防措施。     

建筑垂直运输机械实用电气控制系统设计和应用

针对井字架等垂直运输机械的缺陷，结合施工现场的实际需要，运用电气控制原理，设计出具有功能齐全、工作效率高、安全可靠、经济实用的“建筑垂直运输机械电气控制系统”，并对该系统的构成和工作原理进行了阐述。     

离心泵机械密封的故障分析及对策

本文简要介绍了离心泵机械密封的结构和各部分的工作原理,列举了机械密封常见的失效形式并分析其失效原因,结合双兰线投产期间机械密封产生的故障,分析一些基本的处理办法。     

浅析一种新型高温油泵机械密封的应用

本文介绍了某炼油企业减粘装置高温油泵机械密封的改造实践。一种新型串联的机械密封的结构与工作原理，并阐述了机械密封改造前后的运行对比。     

球杆仪在机床故障诊断与误差补偿方面的应用

球杆仪工作原理及误差补偿方法。通过球杆仪的图形快速诊断功能可分析伺服系统的机械误差,有效进行伺服补偿和机械调节的对策。     

波纹管机械密封在油田生产设备上的应用

机械密封的组成、工作原理、特点及选用,并对机械密封常见渗漏现象提出原因分析和解决方案,通过波纹管机械密封在油田生产设备上的应用,维修成本降低,节能降耗明显。     

新型非接触式机械密封在丙烷泵上的应用

对丙烷泵常用接触式机械密封的泄漏情况进行分析,综述自主研发的新型非接触式机械密封工作原理、特点及其在丙烷泵上的成功应用.     

DS100-260/10A泵机械密封泄漏分析及检修

DS100-260/10A泵为卧式多级离心泵,机械密封泄漏,分析机械密封工作原理、结构,对安装尺寸进行详细测量,找出密封失效原因,给出检修方案。     

机械密封泄漏的原因和解决措施

离心泵是油品储运系统中的常用设备。以离心泵的投产试车为例,简述离心泵机械密封的结构与原理,分析机械密封泄漏失效的原因与处理策略。     

从传统打样、数字打样和远程打样到屏幕软打样

传统打样传统意义上的打样是通过一台打样机输出印刷校对样张,因为其运用原理和印刷相同,所以客户一般认为传统打样可以表现出来的效果,在实际印刷时也可以表现出来。实际上,通常使用的打样机采用的是圆压平、左右往复运动的机械原理和湿压干的工艺过程,并且网点增大率较小。而印刷机采用的是圆压圆、旋转运动的机械原理和湿压湿的工艺过程,网点增大率比打样要大。     

The Precautionary Principle and the law of unintended consequences

The purpose of this paper is to explore within a political economy framework the application of the Precautionary Principle to food and agricultural policy. The paper reviews the Precautionary Principle in general, but also raises issues associated with unintended consequences arising from it. In addition, the paper provides a general model of political economy that includes both precaution and consequences, discusses issues related to precaution and irreversibility, and illustrates how unintended consequences can affect welfare.     

Lancaster's principle of efficient choice : An empirical note

Lancaster's Principle of Efficient Choice is submitted to an empirical examination, using data from Consumer Reports. The results give only moderate support for that principle.     

生产钨酸钙过程中的除钼工艺

阐述了生产钨酸钙过程中除钼的原理，并提出了具体的操作工艺。     

让IBM搞定Sun吧！

无论是硬件、软件，还是客户，Sun对IBM都具有不菲的商业价值，而且具有丰富并购经验和强大企业文化的IBM才是收购Sun的唯—候选人。     

Performance evaluation of production systems monitored by statistical process control and off-line inspections

Quality and productivity performance measures are very often considered in separate phases of the production system design process. However, the production system architecture affects the efficiency of the quality control system as well as the quality control configuration has an impact on the performance of the production system.The paper proposes a new analytical method for evaluating the performance of production systems in which statistical process control (SPC) techniques are implemented. Machines behaviour is monitored by measuring quality characteristics of the produced parts through off-line inspection devices and sampling inspections. The numerical results show the good accuracy of the proposed method, provide new insight in the relations among the two areas and pave the way to the joint design of production logistics and quality control systems.     

一种序列图像中的人脸提取算法

主元分析法是一种有效降低维数和提取特征的方法,在对主元分析法改进的基础上,提出了一种运动目标检测及人脸提取技术。首先以3帧原始图像序列为训练集,用改进的主元分析法计算特征向量,其中第1特征向量和第2特征向量的乘积代表了原图像序列中的运动对象,将这个特征向量定义为特征前景;然后,用平方投影函数提取特征前景中的人脸。实验结果表明,该方法可自动提取运动图像序列中的人脸,且计算简单,准确率高。     

Lockout/tagout and operational risks in the production control of manufacturing systems with passive redundancy

This paper addresses problems associated with production control and occupational safety in a manufacturing system prone to failure involving two machines working in passive redundancy. Machines turning out one part experience two modes of failure and repair: firstly, where failure occurs when a machine remains in fair condition; and, secondly, where such failure results in outright breakdown. Accordingly, we examine both modes of failure for their impact on a flexible manufacturing system (FMS) with respect to production control in terms of costs associated with lockout/tagout procedures and corrective maintenance. This study seeks to identify optimal costs related to backlogs, inventories and maintenance over an infinite planning horizon, along with levels of occupational risk where production control includes efficient planning of lockouts/tagouts. Our study offers numerical methods which may be employed to achieve optimal conditions in setting control policies. A numerical example and sensitivity analysis support this approach.     

工科类高职院校《化工原理》教学改革与实践

"化工原理"课程是工科类高职院校学生必修的一门基础技术专业课,针对高职院校的教学模式和培养目标及本课程的教学特点和学生基础普遍较薄弱的特点,从教学内容、教学手段、课程体系等方面进行改革。打破学科教育的模式、理论课程与实践课程的界限,加大实践教学比例,突出实践技能的培养,建立以职业能力培养为根本的课程体系。     

The Insolvent Thrifts of 1982: Where Are They Now?

In 1982, 237 thrifts were GAAP (Generally Accepted Accounting Principle) insolvent. By 1987, 92 of these were either merged or closed and 77 remained insolvent. The remaining 68 were GAAP solvent with an average GAAP-to-total-assets ratio of 5.6%. The purpose of this paper is to identify the factors that affected the probability of solvency for the 1982-insolvent thrifts over the period 1983–1987.
To identify these factors, the probability of insolvency is modeled in each year between 1983 and 1987 using logistic regression. Because a thrift can earn its way out of insolvency or raise outside capital, the probability of solvency is a function of the infusion of outside capital along with balance sheet and income statement ratios reflecting the thrifts earning ability. The only variable consistently significant in each year is the variable reflecting the raising of outside capital.     

A LOCATION MODEL WITH PREFERENCE FOR VARIETY*

We propose a new location model where consumers are allowed to make multiple purchases (i.e., one unit from each firm). This model may fit many markets (e.g. newspapers, credit cards) better than existing models. A common feature of these markets is that some consumers are loyal to one brand, while others consume more than one product. Our model yields predictions consistent with this observation. If firms are allowed to choose their locations on the interval, then spatial differentiation may not be maximal and in some cases it may even be minimal. Thus, under certain conditions, we restore Hotelling's Principle of Minimum Differentiation.