过共晶Al－Si合金共生区激光表面处理

用２ｋＷ连续ＣＯ２激光对过共晶Ａｌ－１８Ｓｉ合金以不同能量密度和扫描速度进行快速熔凝处理。用扫描电镜、电子微区分析仪分析了微观结构。从计算机对Ａｌ－Ｓｉ合金ｆ－ｎｆ系统的非平衡理论计算所得的共生区及实验结果的分析可见，当能量密度和扫描速度决定的凝固条件处于共生区中部时，过共晶Ａｌ－Ｓｉ合金激光表面处理可以得到共晶间距低于２００ｎｍ的完全共晶结构。     

单色光石英退偏器的退偏机理及性能研究

研究了单色光石英退偏器的退偏机理；定义了退偏度作为衡量退偏器性能的物理量。从实验上在４４０～９２０ｎｍ的光谱范围测试了器件的退偏度，结果表明：只要器件的结构角适当，或者适当调节入射光束的截面大小，便可对某一单色线偏振光实现很好的退偏。     

宽温环境下磁光盘写入光功率的优化

利用有限单元法研究了环境温度、写入光功率、磁光盘膜面温度分布三者间的关系，在此基础上导出了宽温环境下的最优写入条件，该条件为优化宽温磁光盘读出性能提供了依据。     

注蒸汽燃气轮机最佳注汽量的研究

文中首先从部件的热平衡角度出发对注蒸汽燃气轮机循环进行了热力学分析,建立了相应的热力过程计算模型,在压比π＝８－４８,透平进口温度ＴＩＴ＝９００－１３００℃的宽广范围内对ＳＴＩＧ进行了性能模拟,对最佳注汽量和性能之间的关联进行了广泛深入的研究。     

高频声表面波压控（调频）振荡器的研制

本文讨论了声表面波压控(调频)振荡器的原理及设计方法,并实际制作了振荡器,中心频率为657MHz,频偏约为1.5×10~(-3),平均压控灵敏度为98kHz/V,线性度±2%,温度稳定度为±3.7×10~(-5)(-20—+60℃)。     

远红外辐射釉料

远红外辐射釉料是一种非晶态结构的高效远红外辐射材料,由高效辐射材料和过渡性基质材料组成。本文介绍了高效辐射材料和基质材料各自的和组成后的配方、特性以及烧结工艺,给出了远红外辐射釉料光谱图、X射线衍射图等,得出在高于500K时的全法向发射率ε>0.90,热膨胀系数为3×10~(-6)℃~(-1),与金属基底相近,机械强度高,可广泛应用于军事加温装置和民用加热设备。     

钕玻璃激光放大器反转粒子数的荧光测定法

本文报道了通过测量钕玻璃激光放大器在一定泵浦功率下的荧光波形的方法,获得放大器中反转粒子数密度随时间的变化关系,进而得到反转粒子数密度达到最大值的时刻的测定方法及实验结果。     

Image estimation using fast modified reduced update Kalman filter

The authors have proposed some modifications of the reduced update Kalman filter (RUKF) as applied to filtering of images corrupted by additive noise. They have reduced the computational complexity by reducing the state dimensionality. By doing so, it is shown that the computational requirement is reduced by an order of magnitude while the loss of performance is only marginal. Next, the RUKF is modified using the score function based approach to accommodate non-Gaussian noise. The image is modeled as a nonstationary mean and stationary variance autoregressive Gaussian process. It is shown that the stationary variance assumption is reasonable if the nonstationary mean is computed by an edge and detail preserving efficient estimator of local nonstationary mean. Such an estimator, called the hybrid multistage medium D (HMSMD) filter, is also described. Detailed experimental results are provided which indicate the success of the new filtering scheme     

Rigorous analysis of 3-D planar circuit discontinuities using thespace-spectral domain approach (SSDA)

The space-spectral domain approach (SSDA) has been developed to determine scattering parameters for arbitrarily shaped multilayered planar MIC/MMIC discontinuities. Although the basic framework was introduced previously, only resonant frequencies of planar circuit discontinuities could be calculated. The SSDA presented is not only significantly extended, but also introduces the concept of self-consistent hybrid boundary conditions to replace the modal source concept in the feed line. A general error function is derived to provide a direct assessment of the discretization accuracy. The convergence behavior of this method is investigated, and current standing-wave profiles along microstrip throughlines with matched, open, and short-circuited conditions are given. S-parameters for several microstrip discontinuities with abrupt and smooth transition are obtained to demonstrate the flexibility of the approach     

钙—铈氟碳酸盐矿物中BmSn型新多型的发现及其微结构研究

利用Philips CM-12分析型透射电镜对四川昌北大型稀土矿床中钙铈氟碳酸盐矿物进行了研究。除证实氟碳钙铈矿(BS)存在3R和6R2种多型外,首次发现和研究了氟碳钙铈矿(BS)存在4H、12H、18R、24R、30R和36R6种新多型;伦琴矿(BS_2)1种6R新多型和B_2S新规则混层矿物2H、12R和24R3种中新多型。电子衍射和晶格象分析表明:该类矿物中众多新多型的产生,主要是由于矿物结构单元层沿(?)轴有序堆垛和[CO_3]的定向周期性变化所致。