深基坑支护——土钉墙的应用

介绍了土钉墙的基本原理和应用范围，通过土钉墙在南方某地铁车站的具体实例，说细介绍了土钉墙的施工工艺及施工方法，总结了土钉墙在应用中常见的问题及处理措施。     

A bistatic SAR mission for earth observation based on a small satellite

The authors present a new scientific space mission consisting of a satellite carrying a receiving- only SAR which receives the signal transmitted by the ENVISAT-1 SAR. The integration of ENVISAT-1 SAR and bistatic radar data offers an improved potentiality of surface classification, three-dimensional observation, and the opportunity of advanced scientific experiments in the field of bistatic scattering. The small satellite nominal orbit and the attitude manoeuvres are designed in order to maintain an adequate overlap between the two radar swaths along the whole orbit, taking into account the ENVISAT-1 attitude and pointing. A preliminary satellite design (2-year lifetime) is then performed to evaluate the orbit decay and to determine the appropriate orbit manoeuvres (every 4 days) to control the satellites relative phase. The numerical simulation shows that a spacecraft of about 584kg is able to meet the mission requirements.     

High speed driving of a gain-switched laser diode with anexponential transmission line

With the increase of information capacity of an airborne system, high speed driving of laser diodes have been of interest. In order to match the low resistive LD, proposed in this paper is an exponential transmission line, which is used as preshaping to compensate the pattern effect in gain switching of laser diodes. It also will be used to overcome the effect of parasitic elements in high speed driving to improve the rise and trail edges of the output waveform. An accurate circuit model of the exponential line for the PSPICE program has been developed and simulations are conveniently carried out by employing PSPICE     

高职高专院校校园网构建的思路

高职高专学校规模一般都不是很大 ,在校园网建设中可供选择的方案很多 ,选择一个合适自身的方案是非常关键的。满足现在应用并着眼未来发展应该是高职高专校园网构建所应遵循的基本思路。     

用于高压动态校准的快开阀装置

介绍一种高压快开阀装置。它可产生３７０ＭＰａ上升时间小于２０μｓ的阶跃压力，用于对高压传感器进行动态校准。     

复合材料层板中就位横向拉伸强度的研究

本文利用弹性力学和断裂力学方法对纤维增强复合材料的横向拉伸强度进行了分析，其中考虑了９０度开裂层厚度和开裂邻层的约束效应的影响，推导出正交各向异性对称铺层中昨合就位横向拉伸强度的数学表达式，得出开裂层的厚度和约束邻层铺设角对就位横向拉伸强度都有影响的结论，理论计算与Ｆｌａｇｇｓ实验结果吻合较好。     

GPS based onboard and onground orbit operations for small satellites

In extension to common applications such as groundtrack displays and antenna steering, the SGP4 orbit model is proposed for operational orbit determination in small satellite missions. SGP4 is an analytical orbit model for Low-Earth orbiting satellites that is widely used for the propagation of NORAD twoline elements. Twoline elements may hence be generated completely independent of NORAD. Their use as exclusive source of orbital information simplifies the operations concept and reduces mission costs through the extensive use of existing low-cost mission support software. Due to small computer resource requirements of 8–10kByte, the SGP4 model may also be applied for onboard orbit computations making use of e.g. a 80186 processor, thus ensuring full compatibility of ground-based and onboard operations. The proposed approach is particularly suited in combination with a space-borne GPS receiver, were the C/A-code navigation solutions are treated as measurements that are adjusted in a least-squares sense using the SGP4 model. As consequence, inherent drawbacks of the pure navigation solutions such as data gaps and scatter as well as limited velocity accuracy are avoided, while the operational navigation activities are kept at a minimum. The feasibility of the concept is illustrated based on real GPS navigation data from the TOPEX/Poseidon and the MIR space station with an inherent data quality of 50–100 m. It is shown that 3 hours of data within a 4 day period are sufficient to keep the position error within 4 km, that is considered sufficient for most applications.     

飞机超差结构疲劳寿命量化评定

依据美机实用手册介绍的疲劳寿命S-N方程,对超差结构疲劳寿命推导出了一个量化评定方程。并应用该方程对一些典型结构超差形式具体地进行了疲劳寿命量化评定。实践证明,用本文介绍的方法对超差结构疲劳寿命进行定量评定,不仅简捷明快,而且结果可靠。     

光敏元件与光传感器的市场动态和发展

介绍了光敏元件与光传感器技术的发展及在国民经济和军事领域中的重要怍用；分析了国内外光电子产业的市场动态与发展趋势；论述了我国光电子产业面临的机遇和挑战。     

装备维修任务模型研究

首先建立了确定装备维修保障维修任务量模型,在此基础上运用任务安排模型给出了任务数多于维修人员数和维修时间有限两种情况下的处理方法,能比较科学的根据确定的维修任务和维修人员的情况实现对维修任务的分配.