微带巴伦馈电圆锥等角螺旋天线设计与实验

无源雷达导引头一般采用宽带天线以满足对空间辐射源的探测和跟踪。圆锥等角螺旋天线具有宽频带和圆极化的辐射性能,因此它是一种合适的无源雷达导引头天线实现方案。为了满足实际项目的需要,本文开展了圆锥等角螺旋天线的设计和实验研究。设计了具体的天线结构和参数,采用微带粘结技术实现圆锥表面共形的等角螺旋天线臂的加工和焊接。设计了一种超宽带微带平衡-不平衡转换器(巴伦)以实现对设计天线的馈电。在微波暗室内对加工的天线进行了测量,给出了辐射方向图、增益、轴比等测试结果。实验结果表明,对于频带1GHz到5GHz工作频率范围,本文设计和加工的天线性能可以满足技术要求,其实验结果为本天线的实际应用奠定了基础。     

均匀圆阵中的波束合成技术

针对均匀圆阵天线的阵列布局,建立了天线阵列对信号的接收模型,提出了一种实用的直接加权波束合成技术。在分析了系统误差来源并修正了系统误差校准模型的基础上,给出了详细的波束合成理论推导。结合实际系统给出了工程上的具体实现,并运用正交校准技术对由设备通路引起的系统误差进行校准。对该算法进行计算机仿真验证其可行性,并与实际效果图进行比较,指出算法的优点和不足。所给出的理论和方法都通过了工程检验,具有一定的实用性。     

联合时空特征的视频分块压缩感知重构

为了提高视频压缩感知(CS)重构算法的率失真性能,该文提出利用视频的时空特征进行联合重构。为了不引入过多的复杂度,采集端以固定采样率对帧内各块进行测量;重构端则在最小全变差(TV)重构模型的基础上,分别加入利用时空自回归(AR)模型和多假设(MH)模型所形成的正则化项,以提高预测-残差重构的性能。另外,考虑到视频源的统计特性在时空域中是动态变化的,讨论了5种不同的帧间预测模式对重构精度和重构计算复杂度的影响。仿真实验表明,所提出的重构算法能够以一定的计算复杂度为代价有效地改善视频重构质量,且在关键帧采样率高于非关键帧的情形下,帧间预测模式的改善也可一定程度上提高视频重构质量。     

液晶光阀光电导层光吸收系数的研究

用化学气相沉积法制备了液晶光阀中光电导层———非晶硅薄膜,从实验中得出最佳制备工艺的参数取值。给出了用包络线法测量非晶硅薄膜光吸收系数的原理,测量了样品的光吸收系数随波长的变化规律。得到样品在最佳工艺条件下的光吸收系数高于1×103cm-1。     

Adaptive reconstruction technique for the lost information of the rectangular image area

The adaptive reconstruction for the lost information of the rectangular image area is very important for the robust transmission and restoration of the image. In this paper, a new reconstruction method based on the Discrete Cosine Transform (DCT) domain has been put forward. According to the low pass character of the human visual system and the energy distribution of the DCT coefficients on the rectangular boundary, the DCT coefficients of the rectangular image area are adaptively selected and recovered. After the Inverse Discrete Cosine Transform (IDCT), the lost information of the rectangular image area can be reconstructed. The experiments have demonstrated that the subjective and objective qualities of the reconstructed images are enhanced greatly than before.     

The effects of oxygenation aeration treatment on dissipation behaviors of tricaine mesylate in carp (Cyprinus carpio) muscle and water

Tricaine mesylate (MS-222) is one of the most used anesthetics in fish. It can be absorbed by the human body via food consumption, with related detriments to human health. In this study, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was developed for the determination of MS-222 in carp muscle and water samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). For cleanup procedure, multiplug filtration cleanup (m-PFC) method with n-Hexane delipidation was adopted. The extraction solvent, cleanup methods and sorbents were optimized. All method validation parameters were in the acceptable range. The dissipation behavior study was followed by the method development. Firstly, the anesthesia dose and time were optimized in application study. Secondly, carps were revived for different period of time with (experimental group) and without (control group) the oxygenation aeration treatment to compare the dissipation rate of MS-222. After being anesthetized for 6 h at 50 mg/L and 12 h of elimination, the concentrations of MS-222 in crap muscle and water of experimental group was lower than those of control group. After 36 h of elimination under oxygenation aeration, over 90% of MS-222 was dissipated in carp muscle. The results showed that the half-life of MS-222 in carp muscle was 6.2 h. The findings suggested that the commonly-used oxygenation aeration treatment in aquaculture production had potential effects in accelerating the dissipation of MS-222 in carp and water. In this study, three days of withdrawal period was recommended in carps after MS-222 administration under oxygenation aeration.     

镀膜法获得的超辐射发光二极管的特性分析

在考虑了反射率与波长有关这一基本事实后，用图示方法对由镀膜法获得的超辐射发光二极管（ＳＬＤ）的特性进行了分析。结果表明：在判定减反射膜镀得好与不好的时候，最低反射处波长控制的准确性与最低反射率本身的大小都很重要；同时，也可以看到单面镀膜的ＳＬＤ振荡波长与增益峰值波长不重合的现象。     

低频振荡中电磁转矩系数的计算

复转矩系数法在电力系统低频振荡对系统稳定性影响的研究中起到了重要的作用。随着电网技术的快速发展,振荡模式和起因变得越发复杂,之前的电力系统电磁转矩系数法在现有大型电力系统的稳定性分析中已基本失效。因此,如今我们有必要在原有的技术上提出进一步的改进和创新。     

多晶硅薄膜压阻系数的理论研究

利用应力退耦模型,分别对多晶硅薄膜晶粒中性区和晶界势垒区的压阻系数进行了理论分析,并推导出多晶硅压阻系数的表达式.实验结果表明,利用文中推导出的理论公式所获得的计算值与实验测量结果基本符合,所给出的有关多晶硅压阻系数的理论结果可以作为多晶硅特性分析的理论依据.     

相关杂波的AR谱模型及其研究

研究了相关雷达杂波功率谱特性的ＡＲ模型及其模拟方法，提出了具有约束条件的修正ＬＥＶＩＳＯＮ递推算法和ＡＲ模型阶数估计方法，并与现有功率谱估计方法进行了比较，同时给出了计算机模拟结果。