INMARSAT 21世纪工程——全球个人移动卫星通信

本文概述INMARSAT 21世纪工程的规划及为实现这一规划,INMARSAT组织在本世纪末正在进行和即将进行的一系列卫星通信技术工作。着重阐述INMARSAT 21世纪工程的业务性能以及对三种卫星布局方案进行抉择的新动向。     

Poly(3-octylthiophene) as semiconductor for schottky barrier: Effects of doping and storage time

Schottky diodes of aluminium/poly(3-octylthiophene)(P30T)/indium-tin oxide with large active area are prepared by using the proposed new casting technique. Their rectifying behavior and junction characteristics are dependent on whether the P30T is doped and on the storage time, but independent of the thickness of the P30T layer. The present technique can also be applied in a fabrication of electronic devices with other soluble conjugated polymers.     

环境中氚和碳-14

本文介绍了加拿大恰克河实验室有关氚和碳－14在环境中行为和评价的研究。     

浅谈会计信息失真的成因及对策

阐述了会计信息失真的表现形式及其危害性，从会计自身、内控制度、外部审计、道德观念、执法等方面分析了会计信息失真的原因，并从完善法规制度、实行会计委派制、健全会计监督体系、加强立法和执法力度、更新观念、提高素质等方面提出了治理会计信息失真的办法，从根本上杜绝会计信息失真的现象。     

中厚板轧制边部不均匀变形机理的探讨

通过分析宽中厚板轧制过程中的边部不均匀变形，探讨了其影响因素及大宽度板“切边纵裂”的产生原因，提出了解决问题的具体办法。     

研究生生态型学术文化建设的探讨

本文立足学术文化研究的现状和意义,引入生态学相关理论构建了生态型学术文化模型,并在此基础上建立了相应的评价体系,针对研究生生态型学术文化作了综合评价,从而导出其“五维一体、协调发展”的优化模式。     

多年鼎足,今朝一统--国家信息安全产品认证管理委员会成立

我国信息安全产品认证管理委员会的成立,标志着建立统一的信息安全认证认可体系的工作进入了实质性的实施阶段。有关高层主管纵论统一认证认可的意义、目标和希望,并勾勒出五年发展的大体框架。     

Structure and properties of CE/CTBN/EP blends: II. Effect of EP on the mechanical properties and thermostability of the CE/CTBN system

Carboxyl‐terminated butadiene‐acrylonitrile rubber (CTBN) has often been used to improve the toughness of cyanate ester (CE) resin while sacrificing modulus and thermostability. In this paper, the addition of the appropriate amount of epoxy resin (EP) to the CE/CTBN system is shown to not only increase the modulus and thermostability of the blend, but also improve the toughness. The values of impact strength showed a maximum for the CE/CTBN/EP 100/5/5 blend. The temperature of 10 % weight loss (T₁₀) improves from 376 °C for CE/CTBN 100/5 to 407 °C for the CE/CTBN/EP 100/5/2.5 blend. It is proposed that addition of the appropriate amount of EP can decrease the mobility and increase the stability of CTBN via the reaction between the terminal carboxyl group of CTBN and the hydroxyl group of EP. But a very high EP concentration will decrease the crosslinking density of CE, consequently reducing the mechanical properties and thermostability of the blends. Copyright © 2004 Society of Chemical Industry     

狭小场地条件下大跨度预应力混凝土拱板的运输及吊装

介绍了大跨度预应力混凝土拱板在狭小场地条件下的起模、运输及空间滑移吊装的方法，经在众多中直粮库中的应用，证明该方法简单、适用、经济。     

Theoretical analysis of RAIM in the occurrence of simultaneous two-satellite faults

Most algorithms on receiver autonomous integrity monitoring (RAIM) are under the assumption of a single-satellite fault, because there is an extremely small probability that significant simultaneous multiple-satellite faults may occur. However, after the implementation of the Galileo system in a few years, there will be more satellites in view for the user to utilise together with GPS satellites, and a combination of them will bring better performance for RAIM. On the other hand, with the help of wide area augmentation system and the use of dual-frequency operation, pseudo-range errors will be reduced greatly. Thus, tighter alert limits are required for RAIM, and formerly `small' errors should not be neglected. All of those factors make it necessary to consider simultaneous multiple-satellite faults. A detailed theoretical analysis of RAIM under the condition of two-satellite faults for both vertical and horizontal directions is presented. The characteristic/max slopes for every pair of satellites are then deduced in order to calculate the tighter vertical/horizontal protection level for RAIM