Asymptotic reduced-dimensional steering strategies for CMG singularity-free control

The geometric singularity problem is one of principal difficulty when using single-gimbal control moment gyros as spacecraft attitude control devices. To overcome singularity, new steering logics are suggested in this paper which results in a reduction in the difficulty of generating gimbal rates around a singular state. One of the suggested steering laws presented is the reduced dimensional singular value decomposition steering law, which adopts the singular value decomposition in reduced dimensional forms. Two other steering laws make use of the least square method in reduced dimensional forms. All of the suggested steering laws have been generated for the compensation of the torque insufficiency. These logics are verified mathematically and simulations at a singular condition and non-singular condition are performed to see how well they work.     

NZ-24仪器软件故障的快速解决方法

NZ-24地震仪在野外施工时软件经常出现故障，要恢复软件既烦琐，又耗时。利用Ghost软件可快速备份和恢复仪器整个硬盘数据，一旦软件再出故障，只需做简单的硬盘数据恢复即可。本文介绍了使用Ghost软件快速备份、恢复数据的具体方法。     

4TYD112型离心空压机联轴器故障的分析及处理

对新冶钢动力厂制氧机组配套的原料空气压缩机故障现象进行了原因分析,并有针对性地提出了处理措施,经运行检验,故障基本消除。     

Effect of processing conditions on the yield and failure response of an aliphatic polyketone terpolymer

The effect of processing conditions on the yield and failure behavior of an aliphatic polyketone terpolymer was studied. Testing and characterization were performed on samples that were extruded in the form of hollow cylinders. We performed the extrusion process at different shear rates and at different cooling rates to assess the effect that process conditions had on the polymer properties. We performed biaxial testing on the samples to characterize the failure envelopes, including the ductile–brittle transition condition for each process condition. The effect of shear rate was negligible, whereas the cooling rate significantly affected the failure behavior. To explain these differences in behavior, we performed characterization via differential scanning calorimetry, wide‐angle X‐ray diffraction, attenuated total reflection IR spectroscopy, dynamic mechanical thermal analysis, scanning electron microscopy, and residual stress measurements. A broad glass transition was found for all samples at temperatures higher than previously reported for this material. Alteration of the processing conditions did not influence the crystalline phase (percentage crystallinity, crystalline orientation, crystallite size, etc.). A change in spherulitic structure was also observed with altered cooling rate and is suggested to have contributed to the change in failure behavior. Residual stresses also affected the behavior of all samples. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 318–334, 2002; DOI 10.1002/app.10334     

三峡水库安坪库岸段斜坡破坏机制及稳定性评价

基于斜坡的工程地质测绘和实验室分析,总结了研究地段区域滑坡规律,引入粘弹性基础板的弯曲破坏原理,对该地段斜坡破坏机制进行分析。从岩体本身的质量和岩体在地球内外营力作用下所表现的自稳性两方面考虑,采用两级模糊综合评判理论对测区进行斜坡稳定性工程地质单元划分,并利用刚体平衡理论验证模糊评判结果。     

5ZV25J-10160窄V胶带失效原因及改进措施

对川南矿区使用的5ZV25J－10160联组窄V胶带的损坏情况进行了观察分析，主要损坏原因有：胶带V形夹角与带轮轮槽夹角不一致，胶带顶部宽度与带轮轮槽开口宽度不符合要求，在传递动力中造成带轮顶部与胶带联结层接触而单根胶带悬空；胶带硫化质量差、配组不当；胶带及带轮安装、调校未达到要求。对此提出如下改进措施：规定胶带V形夹角和带轮轮槽夹角均为40°，单根胶带顶部宽25mm，带轮轮槽开口宽23．4mm；胶带必须严格按规定配组、安装、调校。实践证明，经改进后胶带传动平稳，无异常损坏。     

现场地质预测与决策技术

油气的生成、运移、分布、成藏、保存具有规律性，技术人员可以依据其规律性对地下地质情况进行推理、预测和决策。钻井过程的现场地质预测技术方法主要是外推法、因果法和直观法三大类。外推法是常用的预测方法，包含了岩性、沉积旋回、标志层、标准层、重矿物等岩石地层学对比方法和生物地层学方法及地球物理方法。现场地质预测与决策是通过确定预测目标、收集相关资料、进行对比分析、形成地质预测结果、拟定地质决策方案、方案优选、方案实施等环节来完成。该技术是现场地质监督的核心技术，在实践中取得显著成效。     

GaAs FET辐射退化研究

低噪声ＧａＡｓ ＦＥＴ和功率ＧａＡｓ ＦＥＴ经中子辐射都未发生致命性的通或断失效，直流偏置伏态下，其失效模式仅仅表现为源漏饱和电流ＩＤＳＳ的退化降低，据此提出了ＩＤＳＳ退化失效与快中子注量φｎ之间的解析关键式ｌｎｙ＝ａ＋ｂｌｎφ。     

Hardness-stress-strain correlation in aluminium—A simpler alternative to visioplasticity in metal forming

Local stress and strain variations in the deformation zone can be ascertained by measuring hardness. Hardness is correlated with strain and stress. The expressions discussed later are useful in determining the local variations in stress and strain from hardness measurement. It is a simple method compared to visioplasticity. One can estimate the forces required for a forming process. It helps in the choice of equipment, design of tooling and selection of lubricant for the particular process.     

矩形橡胶复合材料层合板几何非线性分析

文中应用简单高阶剪切层合理论和大变形理论对各向异性纤维增强的矩形橡胶复合材料层合板进行了几何非线性分析.与线性理论相比,本文作者进行的层合板大变形状态的几何非线性分析和所计算的层板应力分布,更具有准确性.