Compensation of body shake errors in terahertz beam scanning single frequency holography for standoff personnel screening

In the terahertz(THz) band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed.     

High-Quality InSb Grown on Semi-Insulting GaAs Substrates by Metalorganic Chemical Vapor Deposition for Hall Sensor Application

High-quality InSb epilayers are grown on semi-insulting GaAs substrates by metalorganic chemical vapor deposition using an indium pre-deposition technique. The influence of Ⅴ/Ⅲ ratio and indium pre-deposition time on the surface morphology, crystalline quality and electrical properties of the InSb epilayer is systematically investigated using Nomarski microscopy, atomic force microscopy, high-resolution x-ray diffraction, Hall measurement and contactless sheet resistance measurement. It is found that a 2-μm-thick InSb epilayer grown at 450℃ with a Ⅴ/Ⅲ ratio of 5 and an indium pre-deposition time of 2.5s exhibits the optimum material quality, with a root-meansquare surface roughness of only 1.2 nm, an XRD rocking curve with full width at half maximum of 358 arcsec and a room-temperature electron mobility of 4.6 × 10~4 cm~2/V·s. These values are comparable with those grown by molecular beam epitaxy. Hall sensors are fabricated utilizing a 600-nm-thick InSb epilayer. The output Hall voltages of these sensors exceed 10 mV with the input voltage of 1 V at 9.3 mT and the electron mobility of 3.2 × 10~4 cm~2/V·s is determined, which indicates a strong potential for Hall applications.     

基于免疫蚁群优化的无线传感器网络节点调度研究

提出一种基于免疫优化蚁群算法(QIACO)的无线传感器网络节点调度策略方法;针对传统的蚁群算法在寻优过程中存在的收敛速度慢、容易出现停滞现象等缺陷,借鉴免疫系统的自我调节机制,提出了一种新的疫苗选取策略及疫苗接种方法,设计了基于免疫优化的蚁群算法,达到提高算法的收敛速度和避免停滞现象的发生;通过对MESA算法、蚁群算法、量子遗传算法和QIACO算法在负载均衡性分析、能耗均衡性分析和网络寿命分析进行仿真验证,提出的算法在无线传感器网络节点调度策略中效果最好,能有效地提高网络寿命。     

P型Cd1-xZnxTe薄膜的制备及性质研究

采用Cu对共蒸发法制备的Cd1-xZnxTe薄膜进行p型掺杂。用X射线荧光、X射线衍射、扫描电镜、紫外-可见分光光度计、热探针、四探针和台阶仪研究了不同Cu掺杂浓度下Cd1-xZnxTe薄膜退火前后的组分、结构、形貌、光学性质及电学性质的变化。结果表明掺Cu 10%的薄膜在退火后导电类型由P型转变为N型、电阻率增大了几个数量级;掺铜20%的样品退火后导电类型和电阻率未发生明显改变,退火后薄膜表面较为均匀完整;掺铜30%的薄膜透过率显著下降到10%以下,退火前后均为P型薄膜。     

基于相似系统理论的红外光谱谱图比对方法

通过计算提问谱和数据库中标准谱图的相似度,以查出与提问谱相同或相近的谱图,有助于确定未知物的结构与性质.基于相似系统理论,以红外谱图的峰强、峰位、峰面积为相似元设计比对算法,通过实验得到相似元中不同特征值对计算谱图相似性存在一定的影响,然后采用层次分析法得到相似度计算中不同特征值的权重系数,最后提出一种改进的比对算法,并以峰数弹性作为相似性测度的评价指标.实验结果表明改进后的算法更加准确地反映提问谱与数据库中谱图的相对差异,验证了提出算法的合理性.     

数学分析中的条件极值问题

围绕多元函数条件极值问题展开讨论,指出利用函数凸性来解决优化分析问题的思想方法,并研究了两个与凸性相关的不等式.     

数学分析中的四个等价命题

围绕数学分析的极限理论,给出四个等价命题,包括海涅定理的推广、介值性的刻划、一致连续性的刻划和级数收敛的刻划,相应指出它们在理论上的应用.     

两个含双膦配体和[2,3-f]吡嗪并[1,10]菲咯啉的Cu髣配合物的合成、结构及光谱学性质（英文）

合成了2个新的铜髣配合物,[Cu(dppBz)(dpq)]ClO_4(1)和[Cu(dppe)(dpq)]ClO4(2)(dppBz=1,2-双(二苯基膦)苯,dppe=1,2-双(二苯基膦)乙烷,dpq=[2,3-f]吡嗪并[1,10]菲咯啉),通过X射线单晶衍射分析、元素分析、红外光谱、紫外吸收光谱、荧光光谱、核磁共振光谱和太赫兹时域光谱对其进行了分析和表征。1的中心Cu髣离子通过二亚胺配体和双膦配体共同螯合形成变形四面体结构,2的结构与1类似。配合物2的发光光谱表明它的发光具有金属-配体电荷转移(MLCT)特性。对配合物1和2在0.2～2.8 THz范围内进行了太赫兹时域光谱分析,结果表明0.40～0.90 THz的吸收与中心Cu髣离子的配位有关。     

弹性函数的若干应用

列举了弹性函数在数学分析、经济分析和数值分析三个方面的应用.在数学分析方面利用弹性函数分别给出了函数超(次)加性和几何凸(凹)性的判别定理,在经济分析和数值分析方面利用弹性函数进行了简单的弹性分析和误差分析.     

估计不同环境下的设备可靠性

同型号设备的可靠性根据不同的使用环境发生变化.随着环境指标的不断恶化或改善,可靠性形成环境的函数,称为可靠性曲线.估计出这条曲线后,就可以对未知环境下的设备可靠性给出合理的预测.本文对于对数正态总体研究可靠性曲线的估计问题,给出了估计方法,证明了估计量的一致强相合性,用计算机模拟试验说明方法的可用性.