金属蒸气法制备聚合物固载Pd－Cu双金属原子簇

为了不使用任何还原剂而获得聚合物固载高分散零价双金属加氢催化剂，利用金属蒸气法制备了３种不同Ｐｄ／Ｃｕ质量比的聚合物固载双金属原子簇。透射电镜（ＴＥＭ）和Ｘ衍射（ＸＲＤ）测定表明，Ｐｄ－Ｃｕ原子簇粒度很小，平均直径小于３．０ｎｍ。Ｘ射线光电子能谱（ＸＰＳ）表明，Ｐｄ和Ｃｕ均为零价态。Ｐｄ－Ｃｕ原子簇在异丙叉加氢反应中具有很高的活性和选择性。这些结果提供了令人信服的证据，即金属蒸气法可用于在聚合物孔穴内直接而温和地置入小的零价金属原子簇，而且这样制备的聚合物固载金属原子簇很适合于催化应用。     

On the J-integral in periodically layered composites

When a heterogeneous elastic material is represented by an effective homogeneous elastic solid, average stress and strain fields are used. The meaning of the J-integral in the effective homogeneous solid is investigated. A periodically layered medium is considered. The relation between the J-integrals in the original layered medium and the effective medium is derived.     

热处理WO3电变色膜稳定性研究

采用电子束蒸发淀积ＷＯ３薄膜。根据已有的ＷＯ３薄膜脱水过程结论而选择适当温度对薄膜进行退火处理。在大量含水的和不含水的两类Ｌｉ＾＋电解质中进行比较性着色和消色循环实验，表明在２９０℃以下热退火处理能明显增加ＷＯ３薄膜在含水 电解质中的循环寿命。     

An anthropocentric approach to knowledge-based preventive maintenance

It is common knowledge today that application of sound manufacturing concepts and techniques will only provide cost-effective, long-term return when manufacturing functions are totally integrated with the operators, maintenance engineers and other associated personnel. This paper presents a human-centred methodology and its associated knowledge-based tool, to utilize equipment failure information for the purpose of machine down-time minimization. Based upon a structured and rigorous assessment of each breakdown, and combined with total employee participation, continuous improvement of maintenance function and operational effectiveness of equipment can be made a reality.     

捷克5500m^3／min轴流式高炉鼓风机叶片损坏原因及分析

就５５００ｍ＾３／ｍｉｎ高炉鼓风机动，静叶片损坏事故发生的经过以及有关资料，从几个方面详细分析了事故发生的原因。     

NUMERICAL MODEL FOR DYNAMIC SIMULATION OF TRAFFIC FLOW

ＮＵＭＥＲＩＣＡＬＭＯＤＥＬＦＯＲＤＹＮＡＭＩＣＳＩＭＵＬＡＴＩＯＮＯＦＴＲＡＦＦＩＣＦＬＯＷＷｕＺｈｅｎｇ；ＺｅｎｇＬｉ－ｎｏｎｇ（ＤｅｐａｒｔｍｅｎｔＡｐｐｌｉｅｄＭｅｃｈａｎｉｃｓ，ＦｕｄａｎＵｎｉｖｅｒｓｉｔｙ，Ｓｈａｇｈａｉ２００４３３，Ｐ...     

The As-prepared surfaces of C-axis-oriented Nd1Ba2Cu3Oy thin films characterized using scanning probe microscopes

Recently, superconducting Nd₁Ba₂Cu₃O_y (Ndl23) thin films with high superconducting transition temperature (T _c) have been successfully fabricated at our institute employing the standard laser ablation method. In this paper, we report the results of surface characterization of the Nd123 thin films using an ultrahigh vacuum scanning tunneling microscope/spectroscopy (UHV-STM/STS) and an atomic force microscope (AFM) system operated in air. Clear spiral pattern is observed on the surfaces of Nd123 thin films by STM and AFM, suggesting that films are formed by two-dimensional island growth mode. Contour plots of the spirals show that the step heights of the spirals are not always the integer or half-integer number of thec-axis parameter of the structure. This implies that the surface natural termination layer of the films may not be unique. This result is supported byI-V STS measurements. The surface morphology of the Nd123 thin films is compared with that of thec-axis-oriented Y₁Ba₂Cu₃S_y thin films. Surface atomic images of the as-prepared Nd123 thin films are obtained employing both STM and AFM. STS measurements show that most of the surfaces are semiconductive. The results of STS measurements together with the fact that we are able to see the surface atomic images using scanning probe microscopes suggest that exposure to air does not cause serious degradation to the as-prepared surfaces of Nd123 thin films.     

Assessment model of dam operation risk based on monitoring data

Although the dams produce remarkable social and economic benefits, the threat made by unsafe dams to the life and property of people who live in the lower river area is un-negligible. Based on the monitoring data which reflect the safety condition of dams, the risk degree concept is proposed and the analysis system and model for evaluating risk degree (rate) are established in this paper by combining the reliability theory and field monitoring data. The analysis method for risk degree is presented based on Bayesian approach. A five-grade risk degree system for dam operation risk and corresponding risk degree is put forward according to the safety condition of dams. The operation risks of four cascade dams on some river are analyzed by the model and approach presented here and the result is adopted by the owner.     

Advances in cryptography and information security—introduction of 2002–2006 progress of SKLOIS

This paper introduces the research progress of the State Key Laboratory of Information Security (SKLOIS) in China during 2002–2006. This introduction covers four selected areas with each covering some selected research findings. The four selected areas are: the fundamentals of cryptography; the design, analysis and testing of block cipher algorithms; the design and analysis of security protocols based on computational intractability; authentication, authorization and their applications.