Analysis on absolute measurement of optical coating absorption loss based on photothermal detuning technique

Based on the photothermal detuning technique, the three linear relations among reflectance （or trans- mittance）, temperature rise, and pump beam power are studied to achieve the absolute measurement of absorption loss. The relation between temperature and reflectance and the calculation accuracy of tem- perature rise on sample surface have great impacts on the measured result. The influences of parameters involved in the method and the relation between temperature and reflectance and the temperature model of sample surface are also studied. The results show that the absolute absorption loss of optical coatings can be achieved by the proposed method. The measurement accuracy depends on the temperature model and the relation between temperature and reflectance. The linear relation between reflectance and temper- ature rise has largest slope when probe beam wavelength is 632.8 nm and incident angle is 28°. The linear relation slope between temperature rise and pump beam power decreases with the growing of beam size and modulation frequency. The results provide theoretical and experimental supports for the perfection and further application of the photothermal detuning technique.     

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融通停牌凸显美国投资者对中资公司担忧 融通金融技术有限公司虽然名不见经传，但这只在美国市场停牌的中资公司股票却让投资者心存扣忧。     

许越副教授在本刊发表的论文入选“2009年中国百篇最具影响国内学术论文”

日前,由中国科技技术信息研究所发布的中国百篇最具影响的优秀学术论文正式揭晓,北京航天航空大学化学与环境学院许越副教授在《中国稀土学报》2005年23卷第一期40~43发表的论文:《AZ91镁合金表面稀土转化膜的制备及耐腐蚀性能研究》入选2009年中国百篇最具影响国内学术论文。     

Method to accurate calibrate deposition rates of EUV multilayer coatings

Random thickness error is an important factor which effects the calibration accuracies of deposition rates for extreme ultraviolet （EUV） multilayer coatings fabricated by sputter deposition techniques. A least square fitting method is proposed to determine deposition rates and extract random thickness errors accurately. The validity of this method is shown by evaluating two deposition systems with control abilities of -0.1 nm and better than 0.01 nm respectively.     

Surrogate-based modeling and dimension reduction techniques for multi-scale mechanics problems

Successful modeling and/or design of engineering systems often requires one to address the impact of multiple "design variables" on the prescribed outcome.There are often multiple,competing objectives based on which we assess the outcome of optimization.Since accurate,high fidelity models are typically time consuming and computationally expensive,comprehensive evaluations can be conducted only if an efficient framework is available.Furthermore,informed decisions of the model/hardware’s overall performance rely on an adequate understanding of the global,not local,sensitivity of the individual design variables on the objectives.The surrogate-based approach,which involves approximating the objectives as continuous functions of design variables from limited data,offers a rational framework to reduce the number of important input variables,i.e.,the dimension of a design or modeling space.In this paper,we review the fundamental issues that arise in surrogate-based analysis and optimization,highlighting concepts,methods,techniques,as well as modeling implications for mechanics problems.To aid the discussions of the issues involved,we summarize recent efforts in investigating cryogenic cavitating flows,active flow control based on dielectric barrier discharge concepts,and lithium(Li)-ion batteries.It is also stressed that many multi-scale mechanics problems can naturally benefit from the surrogate approach for "scale bridging."     

Ultrasonic guided wave inspection with array sensors

Ultrasonic guided wave becomes one of promising tool for monitoring various types of structures such as large steel plates, vessels, and pipes in oil, chemical or nuclear industry, because guided waves have ability to travel wide range of the target structure in a single position. However, analysis of guided wave signals acquired from structure is difficult on account of low S/N ratio and its dispersive nature. To improve S/N ratio and overcome dispersion effect, focusing techniques for guided waves are needed. Thus, in this study, focusing techniques for guided waves were developed in order to improve long range inspection ability, and performance of the developed techniques was verified by experiments.     

弯道水流二维浅水模型的修正研究

借鉴有关弯道水流流速分布的研究成果,计入深度平均流速与真实流流速分布差值引起的扩散效应,在正交曲线坐标系下建立了平面二维浅水模型.采用以标准κ-ε模型为基础的曲率效应修正紊流模型模拟紊动应力项,在一定程度上考虑了流线弯曲水流紊动应力的各向异性.应用控制体积法和交错网格法离散方程,并用SIMPLEC算法求解离散方程;同时采用修正后的模型对90°弯道水流进行了数值模拟,并与原模型的计算结果及实测资料进行了比较,结果表明该模型能够有效地模拟流线弯曲水流的水力特性.     

天津博纳高性能色谱核心技术通过验收

由天津滨海企业天津博纳固体材料科技有限公司承担的“十一五”国家科技支撑计划重大项目——高性能色谱分离材料和色谱柱的研制近日通过验收。此举标志着国内企业已掌握高性能色谱行业的核心技术，结束了色谱填料和色谱柱依赖进口的历史。据博纳公司总经理尹铮介绍说，该公司所掌握的技术已经达到国际先进水平，而产品价格却只有国外同类产品的50％左右。目前公司的产品已被国内多家企业和科研院所选用，并成功打入国际市场。     

第6届全国地质与地球化学分析学术报告会(第一轮通知)

为推动全国地质与地球化学分析技术的发展，促进国内与国际学术交流，中国地质学会岩矿测试技术专业委员会定于2009年8月或9月举办第6届全国地质与地球化学分析学术报告会。