RLL码的计算机辅助设计

本文着重讨论计算机辅助设计RLL码的具体实现问题.该过程首先根据RLL码两个参数d,k确定一个编码率p/q,然后构造出RLL码的高阶状态转换-输出符号矩阵并求相应的近似特征向量.最后通过状态分裂和状态归并过程,即可得到一个满足d,k约束的编码输出表.其中状态转换-输出符号矩阵为实现计算机辅助设计RLL码提供了有效的数据结构,而且要优化RLL码编码器,就必须有选择地进行状态分裂.     

高峰值功率重频脉冲固体激光器

综述了高峰值功率重频脉冲固体激光器的发展现状，对其中的Ｑ开关、腔倒空、锁模等窄脉冲技术和放大技术进行了分析，展示了高峰值功率重频脉冲固体激光器的发展前景。     

45号钢二次枝晶臂间距与冷却速度的关系

本文利用可控平均冷却速度的单向凝固实验炉测定了４５号钢在不同平均冷却速度下的冷却曲线，由此得到其在凝固期间的平均冷却速度Ｒ，相应地测量了不同平均冷却速度下试样的二次枝晶臂间距Ｓ２，通过回归，得到了如下关系式：Ｓ２＝７２７Ｒ－０．４１，并将引式成功地应用于实际生产中。     

Performance of absorption refrigeration cycle at maximum cooling rate

The influence of irreversibility of finite-rate heat transfer on the performance of an absorption refrigerator is investigated using an endoreversible cycle model with continuous flow. The cooling rate is adopted as an objective function for refrigerator optimization. The maximum cooling rate and the corresponding coefficient of performance are derived. The optimal performance with respect to heat transfer areas of the refrigerator is analysed. In addition, certain significant conclusions are reached.     

Measurement of the tunnel rate in SIS' tunnel junctions as function of bias voltage

Cryogenic detectors with superconducting tunnel junctions can provide an energy resolution improved by at least one order of magnitude compared with standard semiconductor detectors. While the detection principle was already demonstrated many years ago, the past years were dedicated to the transition from the laboratory sample to practical detectors. Our most favored detector design gives rise to tunnel junctions with electrodes of unequal energy gaps. In such hetero tunnel junctions bias conditions can be established which cause a negative signal current. We report the experimental verification of this effect, and we discuss the yield of charge signal of cryogenic detectors based upon superconducting tunnel junctions.     

128kb／s电视电话系统中数码率缓存器的控制策略研究

本文探讨了电视电话／会议电视的Ｈ，２６１建议中低码率时（ｐ＝２）数码率缓存器的控制问题，提出一种既有宏观预分配又有微观分割的控制策略（简称ＧＡＬＳ），并用测试图像序列进行了计算机模拟。将本文方法与ＲＭ８中有关策略作了比较，实验结果表明图像的主观质量有所改善。     

Experimental evaluation of the strength distribution of E-glass fibres at high strain rates

A bimodal Weibull distribution function was applied to analyse the strength distribution of glass fibre bundles under tensile impact. The simulation was performed using a one-dimensional damage constitutive model. The results show that there were two concurrent flaw populations in the fracture process. The regression analysis using the bimodal Weibull distribution function was in good agreement with experiment.     

泡沫铝的动态压缩性能和吸能性研究

通过测量泡沫铝在动态和准静态压缩条件下的应力 -应变曲线 ,研究了泡沫铝的准静态和动态压缩行为以及不同应变条件下的吸能性 ,并对其应变率效应进行了分析。结果表明 ,在高应变速率和准静态压缩下 ,泡沫铝的σ -ε曲线均表现出弹性变形段、平缓段和密实段三阶段特征 ;泡沫铝的压缩性能具有明显的应变速率敏感性 ,随应变速率的提高 ,流动应力上升 ,吸能性升高     

材质对蜂窝纸板缓冲性能的影响

对两种不同材质的蜂窝纸板静态应力应变性能和动态缓冲结果进行了比较分析。讨论了蜂窝纸板力学性能对应变速度的敏感性及两种纸板的缓冲性能差异。缓冲试验结果表明。在不同的冲击应变率下蜂窝纸板的材质影响蜂窝纸板缓冲性能。