高精度、高稳定恒温电路的设计与研究

现主要介绍的是利用集成电路设计的一种高稳定恒温电路。采用的各部分电路分别为恒压电源电路、模拟采样电路、数字A/D转换电路、51单片机控制电路、键盘输入电路、数字显示电路和温控电路。其中模拟采样电路采用SSR器件,而A/D转换电路采用的是四位半的高精度转换器件,它与51单片机配合选用特殊的电路可实现17BIT的精度,故得到的结果可以精确到0.05℃,只要通过改变软件就可以改变精度,故升级简单方便。     

NiosⅡ处理器在透镜中心厚度测量系统中的应用设计

采用迈克尔逊干涉仪原理测量透镜中心厚度的方法已经得到了理论论证,具有较高的测量精度。本文采用硅光电池对经透镜厚度调制后的激光干涉条纹能量进行测量,设计了前置放大电路、A/D转换电路、按键电路、LED显示电路、并以FPGA为载体设计了NiosⅡ处理器,结合软件设计构成了一个以NiosⅡ处理器为核心的透镜中心厚度测量系统的数据采集,分析和显示子系统。     

双积分A/D转换技术

双积分是一种常用的转换技术,具有精度高,抗干扰能力强等优点。本文介绍了双积分A/D转换技术的原理,及其用51单片机和通用分立器件构成的双积分A/D转换器。     

简易直流电子负载的设计分析

文章描述的电子负载由MSP430单片机、D/A转换器、恒流源调整电路、电压取样放大电路、A/D转换器、液晶显示等部分组成。采用了12位的TLV5618芯片,并且单片机通过它来控制恒流源的输出。恒流源部分中,采用了大功率场效应管IRF640,更易于实现电压线性控制电流。在取样电路中,通过对取样电阻两端的电压进行放大之后送至A/D转换电路,单片机通过它得到相应电压值,进而算得流过负载的电流,整个设计简单、可靠。     

基于PCF8591的I~2C总线A/D、D/A转换

I2C总线是Philips(飞利浦)公司推出的串行总线,整个系统仅靠数据线(SDA)和时钟线(SCL)实现完善的全双工数据传输,文章介绍了具有I2C总线的A/D、D/A转换芯片PCF8591的内部结构图,引脚功能,A/D、D/A转换的控制方法,给出了A/D、D/A转换的软件编程的流程图和实例。     

直流双闭环调速系统研究

本文是基于DSP控制的直流双闭环调速系统,以TMS320F2407A为主控制器,它功耗低,控制功能强,同时,配以相应的接口电路,包括D/A转换器、触发电路等。D/A转换器及触发电路,实现整个系统控制量的输出,达到电动机调速的目的。     

基于STC12C5A60S2单片机的自动称重控制设计

使用压力传感器采集信号、单片机集成的ADC转换器进行A/D转换、光电耦合器件减小干扰、电机的点动控制减小误差,基于单片机设计了一个自动称重电路。实践证明,这个电路完全可以满足普通称重包装要求。     

关于机电一体化系统技术的探讨

文章对机电一体化系统接口的定义与接口的方式进行了较全面的论述,重点阐述微机系统的接口技术,着重详细地分析了A/D转换扩展接口技术和D/A转换扩展接口技术以及光电耦合器接口技术。     

微弱信号检测装置的设计

本设计作为微弱信号检测装置,可应用于强噪声干扰背景下检测已知频率的微弱正弦波信号。系统主要由正弦波与噪声源加法器、纯电阻分压网络、微弱信号检测电路、幅值显示电路四部分组成,以MSP430 MCU为控制处理器的显示电路通过A/D采样将有效值采集并转换为信号幅度值显示在128*64液晶显示屏上,人机交换界面良好。经过测试,系统的各项测试指标达到预期指标,工作性能稳定。     

微弱信号检测装置的设计

本设计作为微弱信号检测装置,可应用于强噪声干扰背景下检测已知频率的微弱正弦波信号。系统主要由正弦波与噪声源加法器、纯电阻分压网络、微弱信号检测电路、幅值显示电路四部分组成,以MSP430 MCU为控制处理器的显示电路通过A/D采样将有效值采集并转换为信号幅度值显示在128＊64液晶显示屏上,人机交换界面良好。经过测试,...     

Development in Information and Communications Technology (ICT) Statistics at the Australian Bureau of Statistics

This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field.     

Value at Risk in the Suburbs: Eminent Domain and the Geographical Politics of the US Foreclosure Crisis

Several US counties and local governments have recently considered a novel solution to the foreclosure crisis. They plan to use eminent domain to compel the owners of mortgage debt—and specifically of private‐label mortgage‐backed securities—to sell the debt to the government at a price reflecting the loan's market value. The government would then restructure the debt and resell it to new investors. The plans are striking because—in contrast to both development‐driven eminent domain and the federal subprime bank bailout—they would force investors to assume asset devaluation and increased long‐term risk. Notably, the plans have emerged as an instance of financialization‐focused politics in suburbs and suburban cities of color, specifically majority‐black and ‐Latino/a suburbs. Local support for the plans, we argue, is rooted in the long‐term disinvestment of these ‘suburbs of exception', which became targets of subprime lending and eventually sites where the ‘financial exception' has been localized. But these demographic shifts, fragmentation and fiscal pressures have at the same time created a suburban political terrain in which the plans have gained their strongest political support.     

Towards a Theory of Serendipity: A Systematic Review and Conceptualization

Serendipity – the notion of making surprising and valuable discoveries – plays a major role in the success of individuals and organizations alike. Previous research has established the importance of serendipity and identified important individual- and organizational-level antecedents. However, the literature has been dispersed and the boundaries of the concept have been blurry, leading to a lack of conceptual clarity and structure, and thus limiting validity and managerial actionability. Based on a systematic literature review, I synthesize existing management-related research on serendipity and explicate the emergence and composition of serendipity in the organizational context. I first identify three necessary conditions that differentiate serendipity from related concepts such as luck or targeted innovation: agency, surprise, and value. Then, I draw from the literature on sensemaking, event-based theorizing, and quantum-based approaches to management to conceptualize the process of cultivating serendipity in the organizational context as a process of enabling potentiality and materialization, and develop a multi-level theory of (cultivating) serendipity. This conceptualization contributes to our collective understanding of how, why, and when (i.e., under what conditions) organizations can leverage the value in the unexpected, which opens up fruitful avenues for further research.     

Accountability of NGOs in Bangladesh A critical overview

NGOs in Bangladesh have been recognized as effective change agents in the socio-economic arena throughout the world. Their contributions in micro credit, non-formal education and primary health care are widely known. NGOs play a significant role in society. NGO accountability, as a result, has become a critical issue. NGO accountability in Bangladesh has been examined here in relation to patrons, clients and themselves. Of the three relationships only accountability to patrons is in a near satisfactory state. Accountability to clients is handicapped by lack of opportunities of beneficiaries to participate meaningfully in NGO policy making. Accountability to themselves is adversely affected due to the adherence to a strictly hierarchical system and the influence of founding and charismatic NGO leaders.     

Towards an Asian model of human resource management? A comparative analysis of China,Japan and South Korea

There has been much discussion regarding the possible decline and weakening of national systems of human resource management (HRM). Yet, culture and institutions are often cited as the major stumbling blocks to this outcome. Such constraints may dissipate in the analysis, particularly if ‘regional clusters’ are considered where geographic and cultural closeness and ‘openness’ to similar economic pressures exist. In such cases, it might be postulated that convergence in HRM will occur. We argue that China, Japan and South Korea represent such a cluster. This article examines these countries, to see if a degree of convergence is taking place and if it is towards an identifiable ‘Asian’ model of HRM. A model of change is presented that distinguishes between levels of occurrence and acceptance. Details of the development and practice of HRM in each country are then set out. The article ends with a discussion and implications section and a brief conclusion.     

Ansätze und Ergebnisse anglo-amerikanischer M&A-Forschung

Based on a review of established U.S. management journals (1995–2003), six schools of thought are identified within the Anglo-American M&;A research: “Capital Market”, “Principal/Agent”, “Industrial Organization”, “Organizational Behavior”, “Human Resources” and “Strategic Management”. The literature review shows that the definition of M&;A success, the methods applied, and insights from empirical research differ according to the respective school of thought. Empirical studies focus on the resource combinations of merger partners, the specific circumstances of merger negotiations, and on integration management as antecedents of merger performance. Unfortunately, empirical findings have not yet provided reliable explanations for M&;A success. Based on the current state of Anglo-American M&;A research, the authors discuss implications for business practice, identify research gaps, and propose areas for future research.     

Introduction of New Technology with a Sound Transition of the Input-Output Structure

We examine the general equilibrium repercussions associated with the introduction of new technologies, using the generalized Leontief system that allows technological substitutions. We show that an untested introduction of cost-increasing technologies in any industry may result in creating a non-productive technological structure that does not satisfy the Hawkins-Simon condition, following the autonomous dynamic adjustment process with structural transitions in the economic system. Therefore, we propose a practicable control scheme of introducing cost-increasing technologies that strictly avoids the creation of non-productive structures in all periods of structural transition, using the available information on the ex ante technological structure.     

The Creation of the Office for National Statistics

A new Office for National Statistics was created in the United Kingdom in 1996 following a series of developments designed to strengthen the relevance and integrity of statistics. This paper describes these fundamental changes and sets out a blueprint for future progress. It also sets current developments in the United Kingdom in an historical and international context.     

What helps? Women engineers' accounts of staying on

We have considerable understanding of the obstacles that women engineers encounter and the reasons that they leave the field, but we know less about what enables them to remain. Adopting an interpretivist approach, this article examines how a group of British women engineers in two FTSE 100 companies account for “staying on” in their male‐dominated work settings. We delineate four specific forms of help that facilitate women's retention in the field. We argue that exposure to help leads to women developing a habitus that enables them to continue working in engineering. To conclude, we draw on our findings to outline HR practices that will facilitate supportive relationships in the workplace and pave the way towards developing more positive organisational climates.     

论现代物流企业的发展观

物流业经过诸多年的发展目前已经成为最热门的行业之一,物流企业的注册数量也与日俱增,达到前所未有的规模。毋庸置疑,任何企业都希望自己迅速做强做大,并成为真正现代物流企业的典型代表,要实现这一目标一个首要问题就是要解决现代物流企业的发展观问题。