核磁共振测井仪接收机设计与实现

受激发条件和氢核响应机理的限制,核磁测井原始回波信号极其微弱。高信噪比的回波信号在反演算法中能够更加真实的反映地层信息,于是设计一个高增益、低噪声的接收机非常关键。基于核磁原始回波信号的幅频特性分析,利用低噪声前置放大器、滤波单元、A/D转换器、改进的数字相敏检波处理单元,设计实现了一个高信噪比多频数字接收机。该接收机已经成功应用于中海油自主研发的核磁共振测井仪(elis magnetic resonance tool,EMRT)上,在渤海油田得到的测井曲线CHI值表明该接收机工作稳定,提取信号信噪比高。     

A study of knowledge engineering tools in power engineeringapplications

This paper presents a global view of knowledge engineering (KE) applications in the field of power systems. In particular, it investigates the choice of commercially available KE tools used in projects of power system analysis, design, operation and planning. The initial viewpoint of the study was to uncover the advantages of the various tools for particular power engineering problems, as established in the literature. The paper starts by identifying and classifying the tools in question. Power areas where KE has flourished are also identified. A list of the KE tools identified in the power literature is then compiled and analyzed. The results of the literature study are complemented by responses to a survey from leading practitioners in the field. The paper draws its conclusions as to the (non-) correlation of tools and applications, and recommends that knowledge modeling serve as an important criterion in the choice of tools     

Analytical tools for power system restoration-conceptual design

A conceptual framework for computer-aided monitoring and assessment during system restoration using analytical tools is proposed. The basic structure is similar to one for security monitoring and assessment (ibid., vol.3, no.1, p.1-9, 1988). State estimation and the related functions, such as observability analysis, bad-data identification and external network modeling which are used in security analysis, are modified for application to system restoration monitoring. In addition to the load flows and optimal power flows that are used in security assessment, a host of analysis/optimization programs is required. These analytical tools are identified and categorized. A knowledge-based expert system architecture is suggested for synthesizing possible control sequences and to select and coordinate analysis procedures for assessing restoration plans. The conceptual design of the knowledge-based system and its interface with analytical tools are presented     

Computer aided tools in gas circuit breaker design

A software tool that allows the numerical investigation of the gas flow in circuit breaker chambers has been devised. A zonal grid methodology, with a corresponding finite-volume flow solver for the Euler equations, has been implemented for the treatment of the intricate geometries of the interrupter. Computational examples to illustrate the validity of the method are presented. Experimental tests were done on full-size breakers, and the results are analyzed using the proposed computational approach     

绝缘用具沿面检测装置的硬件电路设计

针对带电作业中安全防护的重要性,介绍了一个绝缘用具沿面检测装置的硬件电路设计方案。该电路设计简单、原理清晰,具有调压和稳压双重功能。对以SG3525芯片为核心实现2.5 k V电压的高压产生电路,以及对存在缺陷的绝缘用具给出报警指示的电路作出了详细的研究。在设计的最后,还对电路进行了实验研究,验证了电路设计的合理性与正确性。     

机床热误差建模及检测系统模块设计

提出了基于模糊神经网络的数控机床温度与热变形的数学模型,该模型根据输入输出样本自动设计和调整模糊系统的参数,并使传统神经网络中没有明确物理含义的权值被赋予模糊逻辑中推理参数的物理含义。将模糊逻辑理论和神经网络结合,提高了网络的泛化能力。文中给出了模糊神经网络结构、算法的具体实现过程。并通过一个仿真实例说明模型可以将20μm内的热变形补偿到1．7μm内,补偿效果明显。针对补偿技术研究与应用中需要快速采集大量的温度及热变形信号问题,以MSC1210微控制器为核心进行模块化设计,温度采集模块通过SPI接口与上位机DSP连接组成数据采集系统。可以方便、灵活的完成数据采集任务。     

Synthesis tools help teach systems concepts in VLSI design

The VLSI project class at Princeton University has been redesigned, using modern logic and layout synthesis tools, to emphasize system design issues. The design methodology taught in the class allows students to build larger designs; it also allows them to learn, by redesign, how to trade off layout, circuit, logic, and architectural design problems. Two synthesis tools were developed (based on the Oct tool set from UC Berkeley) to generate standard cell layouts: one which takes as input finite-state machine transition tables; and one which generates netlists using C programs. The author describes; what is important for students to learn in a VLSI design class; the design methodology developed to teach this curriculum through a design project; and the CAD tools used to support this design methodology     

一种用于GR仪器PMT的高压电源设计

GR射线探测是石油开发中对井眼中因放射性元素自然衰变产生的GR射线的强度不同来进行地层识别,岩性分析,深度校准的常用方法.GR信号检测时需要采用高性能的高压电源驱动光电倍增管,对烁晶体探测到地层中的微弱GR射线进行放大实现.研究了一种针对GR仪器内PMT工作的高压电源电路,该电路采用PWM的控制方式,体积狭小,转换效率...     

基于测试系统的测试向量工具设计研究

测试向量工具作为集成电路测试系统软件的重要组成部分,其性能直接影响整个自动测试系统的工作效率。通过分析确定了测试向量工具的功能结构,研究了开发测试向量工具的关键技术,并重点对比了使用Table和ReportX控件设计向量工具的方法。经过分析,利用ReportX组件完成了测试向量工具的开发,并将其嵌入到国产测试系统BC3192。最后在实际环境中进行了测试,并验证了测试向量工具的良好性能。通过对ActiveX Control技术的应用,可以使虚拟仪器开发变得更为完善和强大。     

The development of PC based CAD tools for auto-expansion circuitbreaker design

It is shown that, with the current understanding of basic arc physics, CAD tools based on a mathematical model encompassing all important physical processes can be developed to aid the design of auto-expansion circuit breakers. The model takes account of radiation transport, arc radiation induced inner wall ablation, turbulence enhanced momentum and energy transport and the moving parts of the breaker. With the aid of the PC based PHOENICS, a commercial general purpose computational fluid dynamics (CFD) package, the conservation equations for the gas and arc together with the relevant Maxwell's equations can be solved. The temperature, velocity and electric fields within the breaker can easily be visualised and the thermal interruption capability predicted. The effects of changing design parameters can be simulated in detail, thus reducing the number of short-circuit tests. Results are verified by available tests     

Integrating UAHPL-DA systems with VLSI design tools to support VLSIDA courses

A complete operational environment established with the help of state-of-the-art tools, to support courses in design automation (DA) of VLSI circuits, is described. It was accomplished with the integration of two systems: (1) a DA system which automatically produces VLSI layouts of digital systems modeled in Universal Hardware Programming Language (UAHPL); and (2) a set of VLSI tools, which in addition to several other functions can be used for simulation and verification of layout designs. Compared with other approaches, the integrated DA system provides a very simple user interface, fast turnaround time, no restriction on the final structure of the layout, and simulation and verification of all phases of design. The new environment, called UAHPL-based VLSI DA, is excellent for teaching and research at universities     

Sustainability principles and practice for engineers

The Institute of Professional Engineers of New Zealand (IPENZ) Presidential Task Force recognized that there was little direction for practical application of sustainability to engineering practice, and developed a context and vision for that application. A set of sustainability principles for engineers was then developed, based on the long term viability of the planet, intra- and inter-generational equity, and a holistic view for projects and engineering practice - integrating environmental, social, and economic issues. Practical tasks and requirements for engineers, including a checklist was then drawn up to provide further direction to practicing engineers.     

一种面向电力营销服务人员的知识库设计

现阶段营销业务知识具有数量庞大、更新频繁的特点,需要一个专门的知识库来协助一线人员的日常工作。构建了一个开放的知识论坛,人人参与知识的互动讨论。专家定期发起采编流程,将优秀的问答固化,形成论坛知识库;建立了一个强大的知识搜索引擎,对知识论坛、95598知识库、论坛知识库、协同办公系统内的知识进行统一搜索展示;建立了知识库日常运维机制、激励机制来辅助管理。知识库在浙江的应用取得了良好的成效。     

An ultra-line-narrowed high-power F/sub 2/ laser for dioptric design microlithography exposure tools

An ultra-line-narrowed high-power and high-repetition rate F/sub 2/ laser system has been developed for 157-nm microlithography exposure tools with dioptric projection design. The injection locked system (ILS) consists of a low-power seed laser with ultra-narrow spectral linewidth and a high-gain amplifier. More than 25-W output power, a spectral linewidth below 0.2 pm full-width at half-maximum (FWHM) and an energy stability (3-sigma) below 10% have been obtained at a 5-kHz repetition rate and for a delay time range between the two laser stages of about 15 ns. Directly compared with a master oscillator power amplifier system, the ILS had a better performance related to output energy, energy stability, and laser pulse duration.     

Teaching design methodology and “industrial strength”EDA tools in a first-term freshman digital logic course

Perhaps contrary to popular opinion, this paper shows that it is actually quite easy and potentially very beneficial to introduce first-term freshman Electrical and Computer Engineering students to digital design methodology and state-of-the-art digital electronic design automation (EDA) tools. One major observed benefit is that this early exposure creates a high level of enthusiasm which helps students maintain their motivation while working through calculus, physics, circuits, general education, and other foundation classes. Another benefit is that later classes are greatly improved because students can build on the solid skill base developed in this first class. Also of importance, this early work with multiple-solution design problems and EDA tools often helps students decide if engineering is the right career choice for them     

浅析绿色智能化建筑的可持续性

阐述了绿色建筑和建筑智能化之间的相互关系以及绿色智能化建筑具有的典型特点。与传统的智能化建筑进行了比较分析,总结出当今绿色智能化建筑在可持续发展上存在的主要障碍,并对其将来的可持续性作了展望。