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     

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.     

On adaptive spatial-temporal processing for airborne surveillanceradar systems

Implementing the optimum spatial-temporal (angle-Doppler) processor involves two crucial issues: the selection of processing configurations, and the development of adaptive algorithms which can efficiently approach the performance potential of the selected configuration. Among the three available configurations, the joint-domain, the cascade space-time, and the cascade time-space, this work shows that, in contrast to a popular belief, the detection performance potentials of both cascade configurations can fall far below that of the joint-domain optimum. In addition, this work presents a new adaptive algorithm, called the Joint-Domain Localized Generalized Likelihood Ratio detection (JDL-GLR), which is data efficient i.e., with fast convergence to the joint-domain optimum, as well as computationally efficient, together with such desirable features as the embedded constant false-alarm rate (CFAR) and robustness in non-Gaussian interference     

k-ε-g紊流燃烧模型数值研究

本文对k-ε-g紊流燃烧模型中模型系数C_R,C_(g1),C_(g2)的选定和计算浓度脉动均方值g的不同方法进行数值研究。计算结果表明模型系数值的选定直接与化学反应速率有关,而其中C_R影响最大。g的计算虽然可有不同方法,而其中微分方程求解最佳。并用实验数据来验证计算结果。     

企业如何培育忠诚顾客

当今社会，买方市场已然形成，顾客由被动变为主动，地位与作用日益突出，在这种形势下，提升顾客满意度，培养忠诚顾客，日益成为企业的核心任务。本文对顾客满意与顾客忠诚的意义、培育忠诚顾客的途径进行探讨，以期对企业能有所启发。     

8mm衰减标准装置

对8mm衰减标准装置的工作原理、系统设计、主要技术特点、误差分析等进行了详细介绍,并附有测试和分析数据。该装置达到了80dB的量程、全频段和±0.003dB/10dB的准确度。     

调制域测频原理及工程实现

介绍了调制域这一新概念，着重分析了调制域测频方法，给出了所实现的调制域测频系统框图，展示了调制域测试的关键技术、内插技术和无间隔计数技术，介绍了游标内插法，独立提出了斜波内插法和孪生链。     

高温超导X波段带通滤波器研制

本文选用 10× 15× 0 .4 4 m m3双抛 L a Al O3衬底上外延生长的优质双面钇系高温超导 (HTSC)薄膜的Yba2 Cu3O7(YBCO) ,设计并制作了结构紧凑的高温超导发夹线微波窄带滤波器。该滤波器工作温度在 90 K以下 ,77K时指标为 :中心频率 9.4 8GHz,3d B相对带宽 1.1% ,带内最小插损 0 .36 d B,带外抑制大于 4 5 d B。另外 ,本文还介绍了高温超导滤波器的精确设计方法 ,并对高温超导滤波器的功率容载、制作等问题进行了讨论 ,同时还研制了具有实用意义的全密封高温超导滤波器外壳 ,仅需液氮制冷即可进入工作状态 ,输入、输出采用 SMA密封接头。