利用闪存芯片作存储器的单片机应用系统

在测量及测试应用系统中,为使现场采集的数据在突发性的掉电过程中不被丢失,且能长时间的保持,可采用32M位闪存芯片KM29N32000TS作为存储器。本文以AT89S51单片机为例介绍它在单片机系统中的硬件连接和软件编程方法。     

改扩建项目中的沉没成本

利用改扩建项目的增量分析法来陈述沉没成本的存在情况及其处理办法。沉没成本有其“沉没”性，但通过再利用，仍可为企业带来效益。     

盟度对N80油套管钢CO2腐蚀膜覆盖条件下阴极阻抗谱的影响

利用极化曲线和电化学阻抗谱技术研究了温度对腐蚀膜覆盖条件下NSO油套管钢在含饱和CO2的地层水中阴极阻抗谱的影响。结果表明：成膜温度升高阴极反应电阻增加,扩散导纳减小,表明阴极反应速率减小。说明温度升高有助于致密性膜的形成．对基体的保护作用增强。3MPa200℃下所成膜覆盖条件下N80油套管铜在不同温度的阴极过程阻抗谱主要由高频容抗弧、低频容抗孤和Warburg阻抗共同组成,随着温度升高,扩散过程增强。     

X80钢管施工常见焊接缺陷和质量控制措施

以目前正在施工的中卫-贵阳联络线输气管道工程焊接中易产生的各类常见缺陷为例,说明了各类缺陷形成的原因和预防措施,指出了日常外观检验和无损探伤中应注意的几个问题。     

ISA总线扩展板的原理及抗干扰措施

本文在论及了总线主设备、从设备、总线操作周期等总线术语概念的基础上提出了当前最广泛流行的 ISA 总线延伸和扩展时的实际技术问题,给出了ISA 总线中输出、输入总线信号的实际延伸和扩展电路;详细论述了主机板CPU 和 DMA 控制器以及 I/O 插接板上 CPU 和 DMA 控制器等主设备分别占有 ISA 总线信号时的时序,总线信号方向控制的实际电路;最后叙述了延伸总线信号时的抗干扰措施。     

城镇化对生态环境的影响路径及其效应分析

随着城镇化水平的提高,生态环境恶化明显,自然资源被掠夺,环境污染加剧。城镇化对生态环境的影响可以通过人口集聚、经济增长、收入增加、产业转移、技术进步和城市扩张等几种路径实现。文章通过理论分析了城镇化对生态环境的影响路径,并采用逐步回归的方法验证影响路径的效应。其中,经济增长可以改善城镇化过程中生态环境恶化的情况,人口集聚、收入增加、产业转移和城市扩张则会导致生态环境恶化加剧。针对实证分析的结果,本文认为需要控制农村劳动力向城市的转移,逐步缩小城乡收入差距,促进产业结构的优化升级,并合理规划城市布局。     

The differing effects of agent and founder CEOs on the firm's market expansion

This paper builds and tests the thesis that CEO influence evolves differently for founders and agents. We theorize that at the beginning of their tenures, founder CEOs can pursue market expansion more aggressively than agent CEOs, because they take office with the combination of motivation, power, and requisite knowledge that agent CEOs build over time. Subsequently, however, founder CEOs have less access to the administrative infrastructure necessary to sustain a growing firm, making them less able than agent CEOs to continue market expansion mid‐tenure and more severely constrained by market complexity. A longitudinal study of cable television operators confirms that the firm's market expansion follows an inverted U‐shape for agents and a downward slope for founders, while market complexity reduces market expansion, especially for founders. Copyright © 2011 John Wiley & Sons, Ltd.     

灰邻域及其边界的特殊性

本文在灰距离空间的基础上,把经典微分学中邻域及其边界的概念推广到有理灰数中去,建立了灰邻域及其边界的概念,并研究了灰邻域边界的特殊性。     

The relationship between product and international diversification: the effects of short‐run constraints and endogeneity

We examine the relationship between growth along the product and international dimension in the short run. We argue that while the presence of fungible intangible resources and economies of scope may create opportunities for a firm to expand along both dimensions, the effect of short‐ run constraints may lead to a trade‐off and a negative association between the two dimensions. In addition, we suggest that rather than being independent, decisions concerning the extent of growth along the two dimensions are likely to be made simultaneously and endogenously by firms after taking into consideration the availability of various resources. We test these propositions by observing a sample of 1,299 firms over the period of 1993–1997. Our results show strong evidence of endogeneity and a negative association between growth along the two dimensions. These findings provide important support for theories of firm growth that have long held that firms are limited in the number of opportunities they can exploit in the short run by various constraints. Copyright © 2008 John Wiley & Sons, Ltd.     

C/S和B/S相结合的安全型管理信息系统开发

为了开发基于C/S(客户/服务器),B/S(浏览器/服务器)模式的高校学生公寓管理系统的网络体系,在对C/S与B/S模式结构进行分析比较的基础上,针对该系统的建设目标和功能要求,对该系统进行了网络体系布置、数据库设计、系统框架设计和系统安全性设计,该系统的实施可以实现C/S和B/S模式结合起来开发管理系统的一种体系结构。     

胀模机构及其结构参数的优化设计

论述了一种旨在改变塑料管端部形状的新型胀模机构的工作原理。在设计中通过对其主要参数的优化计算,避免了在常规设计中出现的干涉,使运动性能显著变好,胀口质量得以提高,使小口径营材特定截面的机械式胀口得以实现。