优化的基于模型的光学邻近矫正算法

提出了一种新的优化的基于模型的光学邻近矫正算法,该算法充分考虑了图形内部及图形之间的光学邻近影响,实现了线段切割和移动步长的自适应性,提高了系统的矫正精度及矫正速度,实验结果表明该算法是有效的.     

AlGaSb/GaSb quantum wells grown on an optimized AlSb nucleation layer

Five-period AlGaSb/GaSb multiple quantum wells (MQW) are grown on a GaSb buffer.Through optimizing the AlSb nucleation layer,the low threading dislocation density of the MQW is found to be (2.50±0.91)×108cm-2 in 1-μm GaSb buffer,as determined by plan-view transmission election microscopy (TEM) images.High resolution TEM clearly shows the presence of 90°misfit dislocations with an average spacing of 5.4 ran at the AlSb/GaAs interface,which effectively relieve most of the strain energy.In the temperature range from T = 26 K to 300 K,photoluminescence of the MQW is dominated by the ground state electron to ground state heavy hole (el-hhl) transition,while a high energy shoulder clearly seen at T > 76 K.can be attributed to the ground state electron to ground state light hole (e1-lh1) transition.     

小型电台转播车的设计实践与思考

广播转播车是一个综合的广播业务技术系统,设计制作涉及到车型选择、车身布置、设备选择、供配电以及数字化播出系统的衔接等功能实现方法。详细介绍了珠海广播电视台广播转播车的设计实践。     

基于边缘探测技术的激光单稳频指标分析

基于边缘探测技术的激光雷达实际应用中,激光器在工作中发射光信号的中心频率会发生漂移,激光频率的漂移过大,会直接影响边缘探测系统的测量精度。采用仿真计算的方法得到碘分子吸收滤波器在470nm~550nm范围内的吸收光谱谱线,以基于边缘探测技术的激光雷达监测大气信道和海洋水下信道环境参数为例,得到适合大气和海洋探测吸收谱线并确定发射激光信号的中心频率。通过理论分析,给出了满足探测要求的激光发射信号单稳频指标,为实际探测系统的设计奠定基础。     

光伏InSb探测器R_0A值的测试与分析

对所生产的光伏 In Sb器件 R0 A值进行了测试 ,结面积为2 .9mm的单元器件 R0 A值在 5.71× 1 0 4～ 5.75× 1 0 6Ω cm2之间 ,50× 1 0 0 μm2的线列器件典型 R0 A值为 3× 1 0 4 Ωcm2 ,对测试结果进行了分析。讨论了器件表面漏电对 R0 A值的影响。     

泰曼-格林干涉仪的一种变形及其应用

本文介绍了泰曼－格林干涉仪的一种变形,分析了在这种情况下所获得的干涉条纹的分布,及其随光程差变化的规律,并介绍了它的应用。     

Effect of tap spacing on the performance of direct-sequencespread-spectrum RAKE receiver

The effect of tap spacing on the performance of a RAKE receiver is analyzed analytically in a frequency-selective fading channel. A continuous time multipath fading channel model is used for the analysis, and the expression of the correlation between the desired signals, interference signals, and noise signals at the output of each branch of the RAKE receiver is derived for various chip waveforms. Since the noise components of each branch signal are correlated to each other, an optimum combining rule based on the maximum-likelihood criterion is derived to gain utmost performance. It is shown that the performance of the system can be improved by setting the tap spacing of the RARE receiver below the chip duration when the bandwidth of the transmitted signal is larger than the inverse of the chip duration. Also, it is shown that the normalized capacity of the system can be increased by using a chip waveform occupying wider bandwidth, which takes advantage of the increased diversity gain merits of a wide-band code-division multiple-access system at the same chip rate. It is noted that the derived combining rule gives diversity gain against the fading process as well as noise whitening processing gain against multiple-access interference at the same time     

An FDTD algorithm with perfectly matched layers for generaldispersive media

A three-dimensional (3-D) finite difference time domain (FDTD) algorithm with perfectly matched layer (PML) absorbing boundary condition (ABC) is presented for general inhomogeneous, dispersive, conductive media. The modified time-domain Maxwell's equations for dispersive media are expressed in terms of coordinate-stretching variables. We extend the recursive convolution (RC) and piecewise linear recursive convolution (PLRC) approaches to arbitrary dispersive media in a more general form. The algorithm is tested for homogeneous and inhomogeneous media with three typical kinds of dispersive media, i.e., Lorentz medium, unmagnetized plasma, and Debye medium. Excellent agreement between the FDTD results and analytical solutions is obtained for all testing cases with both RC and PLRC approaches. We demonstrate the applications of the algorithm with several examples in subsurface radar detection of mine-like objects, cylinders, and spheres buried in a dispersive half-space and the mapping of a curved interface. Because of their generality, the algorithm and computer program can be used to model biological materials, artificial dielectrics, optical materials, and other dispersive media     

A methodology for product mix planning in semiconductor foundrymanufacturing

Since a semiconductor foundry plant manufactures a wide range of memory and logic products using the make-to-order business model, the product mix is an important production decision. This paper first describes the characteristics of the product mix planning problem in foundry manufacturing that are attributable to the long flow time and queuing network behaviors. The issues of time bucket selection, mix optimization and bottleneck-based planning are next addressed. A decision software system based on integer linear programming techniques and a heuristic procedure has been implemented for mix planning. Data provided by a wafer plant has been used to study problems related to product mix planning. It was determined that the suitable time bucket of planning is either one week or one month and the lead-time offset factor should be included in the logic of workload calculation. This paper also presents various facets of product mix decisions and how they should be integrated with operations management