圆柱型阵机载雷达杂波抑制新方法

圆柱型阵天线相对于常规的平面阵天线具有空间全方位扫描、搜索跟踪方式灵活和波束方向性好等优点。该文首先从圆柱型阵机载雷达杂波协方差矩阵特征值分布和杂波功率谱距离向分布两个方面分析了圆柱型阵列与均匀平面阵列之间的区别,得到杂波功率谱随距离变化的结论。然后根据圆柱型阵机载雷达杂波分布特点提出了两种不同的杂波抑制方法,它们能够很好地解决圆柱型阵机载雷达杂波距离向分布非均匀的问题。最后通过仿真实验验证了该文方法的正确性。     

早期视网膜分支静脉阻塞患者倍频固体激光治疗对临床疗效及CMT值变化的影响

本文探讨了早期视网膜分支静脉阻塞患者倍频固体激光治疗对临床疗效及黄斑中心视网膜厚度(CMT)值变化的影响.将因视网膜分支静脉阻塞行激光治疗的30例患者纳入激光组,同期行常规治疗的30例患者纳入对照组,对比两组临床疗效、视力、CMT值变化、眼底荧光血管造影(FFA)检查渗透率及并发症.结果显示,治疗后激光组患者临床治疗总...     

基于CMT技术的非正侧面阵机载雷达杂波抑制方法研究

非正侧面阵机载雷达杂波谱与正侧面阵机载雷达杂波谱的主要区别在于它的杂波二维谱图随距离的变化而变化,杂波自由度相对增加,造成常规的统计型STAP杂波抑制方法不再适用.本文通过对非正侧面阵机载相控阵雷达杂波的分布进行详细的分析和研究,提出了一种基于CMT技术的非正侧面阵机载相控阵雷达杂波抑制方法.仿真结果表明了本文方法的有效性.     

碲镉汞晶片表面加工损伤的电化学腐蚀观察方法

本文报道一种新的观察碲镉汞（ＣＭＴ）晶片表面加工损伤的方法──电化学腐蚀法。文中讨论了电化学腐蚀法的原理，给出了实验结果。实验表明：机械磨抛的ＣＭＴ晶片表面的加工损伤可用电化学腐蚀法清楚地揭示出来；磨抛产生的机械划痕在电化学腐蚀前后一一对应，而且腐蚀后可清晰、直观地看到腐蚀前看不见的机械划痕；结合化学腐蚀的方法测量了一定磨抛条件下Ｗ３．５磨料在ＣＭＴ晶片表面产生的最大加工损伤深度约３２～４０ｐｍ；机械磨抛产生的划痕和其在表面留下的应力沟道区是ＣＭＴ晶片表面在磨抛加工中受到损伤的主要机构。分析认为平均损伤深度主要影响磨抛ＣＭＴ晶片的表面复合速度，而最大加工损伤深度则对ＣＭＴ器件、特别是多元器件性能参数的均匀性影响比较大；故控制好ＣＭＴ晶片表面加工的最大损伤深度也是制备性能均匀的ＣＭＴ多元探测器的一个重要环节。     

容量矩阵法在涡方法中的应用

本文将容量矩阵技术与快速Fourier变换相结合求解非矩形域的Poisson方程,再与格子涡方法相结合,发展了一套求解复杂外形的快速涡方法。作为算例,计算了有厚度平板和楔形体的分离流动,得到了满意的结果。特别是在垂直平板绕流中,模拟出了由于剪切层不稳定性引起的小涡结构。     

As Doping in (Hg,Cd)Te: An Alternative Point of View

Acceptor doping of many II–VI compound semiconductors has proved problematic and doping of epitaxial mercury cadmium telluride (MCT, Hg_1−x Cd _x Te) with arsenic is no exception. High-temperature (>400°C) anneals followed by a lower temperature mercury-rich vacancy-filling anneal are frequently required to activate the dopant. The model frequently used to explain p-type doping with arsenic invokes an amphoteric nature of group V atoms in the II–VI lattice. This requires that group VI substitution with arsenic only occurs under mercury-rich conditions either during growth or the subsequent annealing and involves site switching of the As. However, there are inconsistencies in the amphoteric model and unexplained experimental observations, including arsenic which is 100% active as grown by metalorganic vapor-phase epitaxy (MOVPE). A new model, based on hydrogen passivation of the arsenic, is therefore proposed.     

Capillary electrophoresis for the detection of PMP22 gene duplication: study in Mexican patients

Charcot-Marie-Tooth (CMT) disease is the most common inherited disorder of the human peripheral nerve, with an estimated overall prevalence of 17-40/10 000 [1]. The typical phenotype presents peroneal muscular atrophy and pes cavus [2]. CMT is usually divided into two large types, about two-thirds of the patients have CMT type 1 (CMT1), that affects the layer of myelin (demyelination). In type 2 (CMT2) the nerve fibers are affected (axonal). CMT diseases have autosomal dominant, autosomal recessive, and X-linked inheritance [1]. The most frequent subtype is 1A (CMT1A) with autosomal dominant transmission, secondary in most cases to a tandem duplication of a 1.5 Mb DNA fragment on chromosome 17p11.2-p12 [4-7]. In this region, the codification of the peripheral myelin protein 22 (PMP22) takes place. The severity of the disease varies among patients, even within the same family, from almost no symptoms to severe foot-drop and sensory loss. The PMP22 gene has four exons and is regulated by two promoters located toward the extreme 5'. The origin of the duplication that causes the disease is an uneven exchange of the chromatids during the meiosis. This unequal recombination occurs between two regions that limit the PMP22 gene, described as REP places of 24 kb, proximal and distal [3, 4].     

Two-dimensional analytical subthreshold model of graded channel DG FD SOI n-MOSFET with gate misalignment effect

A two-dimensional (2-D) analytical subthreshold model is developed for a graded channel double gate (DG) fully depleted SOI n-MOSFET incorporating a gate misalignment effect. The conformal mapping transformation (CMT) approach has been used to provide an accurate prediction of the surface potential, electric field, threshold voltage and subthreshold behavior of the device, considering the gate misalignment effect to be on both source and drain side. The model is applied to both uniformly doped (UD) and graded channel (GC) DG MOSFETs. The results of an analytical model agree well with 3-D simulated data obtained by ATLAS-3D device simulation software.     

Influence of the Silicon Substrate on Defect Formation in MCT Grown on II-VI Buffered Si Using a Combined Molecular Beam Epitaxy/Metal Organic Vapor Phase Epitaxy Technique

II-VI buffer layers grown by molecular beam epitaxy (MBE) onto silicon exhibit a uniform, slightly faceted surface morphology. However, a number of surface defects are apparent and these are amplified by the subsequent growth of mercury cadmium telluride (MCT) by metal organic vapor phase epitaxy. Some of these defects have been traced to polishing damage present within the silicon substrate. A range of analytical techniques, including x-ray topography, have been used to track the defects from the substrate through to the buffer layer and into the MCT. Defects of this type will cause dead elements in the infrared focal plane arrays and will be a major cause of low operabilities.