Lanthanum-Promoted Ru／Sepiolite in Ammonia Synthesis

Theiron basedcatalystsforammoniasynthesishavethecommonproblemsoflowefficiency ,highconsumptionofenergy ,strictrequirementforequip ment,andlowoperationflexibility ,etc .,anditishardtoradicallylowerenergyconsumptionbysimplyimprovingiron basedcatalystsproper…     

Effect of gravity on InGaSb crystal growth

The effect of gravity on dissolution of GaSb in InSb melt and growth of InGaSb was experimentally investigated. Experiments were carried out in a GaSb(seed)/InSb/GaSb(feed) sandwich system under an imposed temperature gradient. In the experiments, the GaSb feed crystal dissolved into the InSb melt to supply the required GaSb component for the growth of In_0.1Ga_0.9Sb crystal. Two parameters were considered: (1) the inclination angle (θ) of the sample for gravity as 0° and 53°, and (2) the sample diameter (D) as 9 mm and 5mm. When θ was 0°, the interface was almost flat, indicating that convection was axisymmetric and stable. Whereas the interface was distorted towards gravitational direction when θ was 53°, indicating that solutal convection was dominant. The decrease of growth temperature and sample diameter reduced the distortion of interface and the dissolution amount of GaSb feed. The homogeneous crystals were grown at the initial growth stage by supplying the GaSb component during growth.     

一种主机安全服务包的设计及实现

提出了能在主机上提供本地网络安全保护功能的主机安全服务包，如数据密码保护、网络结点认证、IPSec协议封装、IKE密钥协商、流机制下加密模块的实时化应用等。描述了该安全服务包的设计思想，并对其基于网络协议垫片嵌入方式的实现方式进行了研究。     

Large-scale mapping of boreal forest in SIBERIA using ERS tandem coherence and JERS backscatter data

Siberia's boreal forests represent an economically and ecologically precious resource, a significant part of which is not monitored on a regular basis. Synthetic aperture radars (SARs), with their sensitivity to forest biomass, offer mapping capabilities that could provide valuable up-to-date information, for example about fire damage or logging activity. The European Commission SIBERIA project had the aim of mapping an area of approximately 1 million km² in Siberia using SAR data from two satellite sources: the tandem mission of the European Remote Sensing Satellites ERS-1/2 and the Japanese Earth Resource Satellite JERS-1. Mosaics of ERS tandem interferometric coherence and JERS backscattering coefficient show the wealth of information contained in these data but they also show large differences in radar response between neighbouring images. To create one homogeneous forest map, adaptive methods which are able to account for brightness changes due to environmental effects were required. In this paper an adaptive empirical model to determine growing stock volume classes using the ERS tandem coherence and the JERS backscatter data is described. For growing stock volume classes up to 80 m³/ha, accuracies of over 80% are achieved for over a hundred ERS frames at a spatial resolution of 50 m.     

Monitoring of slow ground deformation by ERS radar interferometry on the Vauvert salt mine (France): Comparison with ground-based measurement

The differential SAR Interferometry (DInSAR) technique has been applied to a test site near Vauvert (France) to detect and monitor ground deformation. This site corresponds to the location of an industrial exploitation of underground salt using the solution mining technique. An area of subsidence has been observed using in situ measurements. Despite conditions unfavorable for InSAR because of the vegetal cover, we show that radar remote sensing observations provide valuable information which substantially improves our knowledge of the phenomenon. An adaptive phase filtering process has been used to improve the coherence level. In particular, our study shows that the geometry of the subsidence bowl is different to that previously assumed using ground-based techniques only. The size of the subsidence bowl (8 km) is larger than expected. This information will be useful for further modeling of the deformation and to improve the coverage of the in situ measurement networks. It also shows that radar interferometry can be used for the long-term monitoring of such sites and to predict potential environmental issues.     

嵌入式操作系统封装层的设计与实现

文中对嵌入式操作系统封装的必要性作了较详细地论述，并以商用嵌入式操作系统VxWorks对通信类产品的封装为例对封装层的设计与实现进行了探讨。     

低合金钢亚温淬火强韧化研究

借助扫描电镜，透射电镜，Ｘ射线衍射仪等对低合金钢２７ＳｉＭｎ亚温淬火的强韧机理进行了研究。结果表明，位错强化，固溶强化，细晶强化及铁素体韧化等综合作用合金钢亚温淬火后强韧化效果较好。     

绝缘材料水树产生及发展机理的研究现状

本文介绍了水树枝的定义、分类以及影响因素,在参考了16篇中外文献的基础上综述了常用绝缘材料中水树的生长过程和引发机理,推导出水树长度与老化时间、电场强度等因素的关系式。     

Tensile and fatigue behavior of Al-based metal matrix composites reinforced with continuous carbon or alumina fibers: Part II. Quasi-unidirectional composite cross-ply laminates

The mechanical behavior (tension, fatigue, and notch sensitivity) of Al-based metal matrix composite (MMC) cross-ply laminates is investigated. The two selected laminates, K139/A357 and N610/AU2, are reinforced by continuous K139 (carbon) or N610 (alumina) fibers. These multiplies consist in the stacking of (quasi-unidirectional) quasi-UD preforms oriented at 0, ±45, and 90 deg, the thermomechanical behavior of the corresponding quasi-UD composites being reported independently (Part I). The investigated cross-ply laminates exhibit attractive static and cyclic performances and a low notch (circular hole) sensitivity. High-resolution microfractography has led to a better understanding of the fracture mechanisms of these materials. In this respect, the role of the transverse bundles is dominant in the tensile and fatigue failure of both laminates. However, the failure surfaces are completely different: long fiber pullout in the K139/A357 laminate and much more planar areas in the N610/AU2 laminate. Due to the rather low notch sensitivity, a large portion of the specimen section was already highly damaged during a non-negligible part of the fatigue life: debonded interfaces in the K139/A357 laminate and multicracked and “crumbled” matrix in the N610/AU2 laminate. These mechanisms are in good agreement with the weak interface in the first case and the very low yield stress of the AU2 matrix, much lower than the fatigue limit of the N610/AU2 laminate, in the second case. Moreover, compared to the quasi-UD composites, the stress concentration around the notch allows further exacerbation of the fatigue mechanisms, much more intense than that attained in “model” composites.