光纤光栅的长度对其峰值反射率的影响

利用耦合模理论,数值分析了当光纤光栅(FBG)折射率变化为均匀分布、直流切趾高斯分布时,光纤光栅长度对其峰值反射率的影响。研究结果对光纤光栅外腔半导体激光器的设计和性能优化具有重要的意义。     

数字放大器—3G无线基站的助推器

为了构筑第三代无线网络,人们需要对现有基础设施进行彻底改造,包括网络的发射基站。配置在无线基站中的新型数字控制功率放大器能够改善频谱利用率和功率效率,从而提高系统容量。PMC-Sierra公司的数字控制功率放大器采用了数字校正信号处理器(DCSP)以及自适应控制处理器和补偿估值器(ACPCE),该放大器可改善无线基础设施的可靠性,同时降低系统成本、规模及复杂性。     

Ultrasonic measurement of the inter-electrode gap in electrochemical machining

During the process of electrochemical machining the dependency of the inter-electrode gap with time and process parameters can be used to determine process characteristics and to define the shape of the workpiece surface relative to the tool surface. Defining process variables to map out the required gap-time function requires the use of time-consuming iterative trials. In-line monitoring of the gap would enable process control and tool to workpiece transfer characteristics to be achieved (for ideal conditions) without the requirement to generate such parameter maps. This work explores the use of ultrasound applied as a passive, non-intrusive, in-line gap measurement system for ECM. The accuracy of this technique was confirmed through correspondence between the generated gap-time and current time data and theoretical models applicable to ideal conditions. Gap measurements are also used to demonstrate and quantify the degree of departure from ideal behaviour for an In718/chloride system as the electrolyte flow rate is reduced from 16 to 4 l min⁻¹. The monitoring of the gap size has also been shown to be effective when determining shape convergence under ideal conditions, for the example case of a 2D sinusoidal profile.     

变风量空调系统

介绍了变风量空调系统（VAV系统）的特点、末端装置的型式以及最小送风量的确定方法，指出了VAV系统的研究重点和发展前景。     

Model checker aided design of a controller for a wafer scanner

For a case-study of a wafer scanner from the semiconductor industry it is shown how model checking techniques can be used to compute (1) a simple yet optimal deadlock avoidance policy, and (2) an infinite schedule that optimizes throughput. in the absence of errors. Deadlock avoidance is studied based on a simple finite state model using Smv, and for throughput analysis a more detailed timed automaton model has been constructed and analyzed using the Uppaal tool. The Smv and Uppaal models are formally related through the notion of a stuttering bisimulation. The results were obtained within 2 weeks, which confirms once more that model checking techniques may help to improve the design process of realistic, industrial systems. Methodologically, the case study is interesting since two models were used to obtain results that could not have been obtained using only a single model. Supported by the European Community Project IST-2001-35304 (Ametist), http://ametist.cs.utwente.nl/.     

On using peak amplitude and rise time for AE source characterization

Acoustic Emission (AE) signals, which are electrical version of acoustic emissions, are usually analysed using a set of signal parameters. The major objective of signal analysis is to study the characteristics of the sources of emissions. Peak amplitude(P _a ) and rise time(R _t ) are two such parameters used for source characterization. In this paper, we theoretically investigate the efficiency ofP _a andR _t to classify and characterize AE sources by modelling the input stress pulse and transducer. Analytical expressions obtained forP _a andR _t clearly indicate their use and efficiency for source characterization. It is believed that these results may be of use to investigators in areas like control systems and signal processing also     

基于Agent的分布式查询优化研究

Internet上异构的软硬件环境以及多种并行机制对分布式查询优化技术提出了新的挑战，文章将分布式人工智能与数据库管理系统两个研究领域相结合，给出了基于Agent的分布式查询优化系统模型，在该系统中，Agent采用了典型的慎思型体系结构，即BDI模.Agent具有信念库，目标库并在此基础上进行学习和推理，多个Agent之间通过协调，协作以及协商以支持分布式数据库系统的动态查询优化和规划的执行，提高系统的查询效率。     

疏浚吹填工程推行项目经理责任承包制管理模式的探讨

阐述了传统管理模式的生存条件及其弊端,对疏浚吹填工程推行项目经理责任承包制管理模式进行了探讨.     

地下燃气调压设施的建设与管理

介绍了地下燃气调压井的建设和管理经验，提出了在城市燃气输配系统中地下调压井的选择。     

平纹织物复合材料的弹性模量预测

利用细观力学的代表体积元(RVE)法,预测了平纹织物复合材料的弹性模量。建立了表征RVE形态的数学模型,分析了细观结构与宏观性能之间的关系,编制了从组分材料的弹性性能推测复合材料的弹性性能的预测程序。对理论预测进行了实验验证,理论值与实测值在一定误差范围内能较好吻合,说明此预测方法具有一定的可靠性。