灾后重建

重建数据 6月25日，国家发改委主了地震灾后恢复重建工作的情况。他表示，据四川、甘肃、陕西三个重灾省统计数据，截至今年4月底，三省灾后恢复重建项目已开工21000多个。完工项目9400多个，完成投资3600多亿元，占规划总投资的30%左右。     

北京市广电局启动支援什邡灾后重建工作

6月18日，北京市广电局召开支援什邡灾后重建工作领导小组会议，正式启动北京广电系统灾后对口援建工作。会议传达了广电总局灾后恢复重建对口支援协调会议和北京市对口援建工作会议精神。会议要求，要严格按照北京市对口支援灾区建设工作的整体要求和广电总局对口援建的具体标准，依法、科学地做好援建工作。要逐步细化各项方案，责任到人，所有援建方案要报北京市对口支援灾区重建规划分指挥部批准后实施。会议成立了援建工作领导小组，研究讨论了对口援建工作的运作方式，并就前期工作开展明确了任务。目前援建工作正在迅速有序进行。     

基于视觉传达的复杂光照图像虚拟重建设计研究

为了提升复杂光照图像虚拟重建后的效果，基于视觉传达对复杂光照图像虚拟重建进行设计研究。利用分水岭变换方法分割图像，通过分析图像的形状异质性，计算出光滑度差异值，将目标轮廓精准地从图像中分割出来，形成独立的图像个体，基于此，通过立体匹配对目标图像进行区域校准，利用视觉传达技术根据分割图像的位置和色彩，计算图像视觉表达灵敏度，进行虚拟重建，实现对复杂光照图像的修复。在实验论证中，对所提方法的重建效果进行了测试，结果表明，所提方法处理过的图像具有较高信噪比，能够较好地还原原始图像，对原始图像的还原率平均达到了94.41%,明显高于对比方法，说明总体重建效果较好。     

基于变行频采样的红外图像重建技术研究

为了使一些单元或线列探测器获得的扫描数据含有相应的空间信息，进而提高获得红外热像的分辨率，提出了圆锥扫描机制下基于变行频采样机理的红外图像完整重建策略。结合圆锥扫描机制下变行频采样的运动特性、优点和采样机理，通过补场搜索重建了导弹架上捕获模式下的完整红外图像。利用空间基准参量，通过计算机仿真给出了变行频采样示意图和重建图像。仿真过程表明这种技术能够有效避免因导弹自旋造成的单场边缘行采样稀疏的缺点，而获得较高分辨率的红外图像。这种技术在投入相对较低的情况下，为目标检测和跟踪研究提供可靠的数据源，具有很好的应用前景。     

基于视觉认知心理特点的图象重建质量分析

本文以作者根据Ｓｔｅｐｐ－Ｌｏｇａｎ人头模型生成的七幅精度相同而质量各异的“重建”图象为基础，分析了上前常用的图象重建质量评价指标的不足，提出了具有明确视觉心理要领的Ｅｅ，Ｅｓ，Ｅｃ评价指标，并对ＡＲＴ，ＳＩＲＴ，ＭＡＲＴ和ＦＢＰ等重建方法的重建质量进行了分析。     

高频重建技术SBR的研究与实现

AAC是MPEG-4标准的音频编码规范，为了提高音频数据的压缩率，往往忽略了音频中所包含的高频成分，只对低频部分进行编码，因此AAC解码器设计中高频重建技术对提高音频质量起着非常重要的作用．本文论述了高频重建技术的原理，并采用SBR技术，实现了AAC音频编码的高频重建，同时性能评测结果表明所实现的AAC SBR系统满足实际应用的要求．     

直方图约束下的康普顿散射图像重建

利用康普顿散射光子能谱可以重建物质的电子密度图像。针对传统的连续近似算法收敛性能差，重建效果不理想，本文提出一种结合直方图约束和Tikhonov—Miller正则化的连续近似迭代算法，加快了收敛速度，改善了重建质量，并给出了计算机仿真的结果。     

在醉生梦死之间

时间之轮飞速旋转，真难感觉川震已经两年了。人在高速中运行久了．使无所埔快慢，这时世，吸引眼球的事太多，近来的天灾人祸也不少，到处都是热点．关心川震灾后重建尤其是幸存者的生活的人怕是少了很多吧。     

由空间频域上的非均匀采样数据重建图象的方法研究

本文深入研究了由空间频域上的非均匀采样数据重建图象的“双线性插值加二维快速傅里叶反变换”方法。它的基本思想是首先确定一个均匀的栅网，然后应用双线性插值交给定的非均匀采样的数据插到这一栅的各个结点上，再对结点上的数据应用二维快速傅里叶反变换，本文提出了确定的原则，讨论了双线性插值，并分析了关于二维快速傅里叶反变换的一些重要问题，将这种方法应用于合成孔径雷达（ＳＡＲ）成象的处理中，得到了满意的结果。     

超分辨率重建技术研究与探索

超分辨率重建技术是指利用一序列低分辨率图像来估计一幅或多幅高分辨率图像。本文对超分辨率重建的概念进行了阐述,较全面地回顾了超分辨率技术近年来的发展历程,对超分辨率重建中的关键问题进行了深入的分析,指出了其优点与不足,最后对其未来的研究和发展方向进行了总结和展望。     

基于光束偏转层析技术的三种Radon变换迭代法

本文通过计算机模拟研究,利用气体温度场的先验知识,考查了用光束偏转层析技术重建三维温度场的基于卷积反投影的三种Radon变换迭代法。作为一种应用实例,测试了某截面上的气体温度分布,并与热电侧测量的值进行了比较。     

The interaction between ELF electric fields and RF survey meters: theory and experiment

An RF survey meter is often used to evaluate the safety of human exposure to RF electromagnetic fields. However, it has been noted that erroneous meter indications occur when the meters are used in strong, extremely low-frequency (ELF) electric fields, such as those found near electric power transmission and distribution facilities. In this paper, coupling between an ELF electromagnetic field and an RF survey meter has been studied theoretically and experimentally. It has been shown that coupling large enough to result in erroneous readings can be caused by unbalanced currents as small as 0.1% of the balanced currents on the transmission line that connects the probe to the readout unit. Unbalanced currents of this magnitude can be caused by capacitive coupling to the probe and readout unit.     

Inertial snake for contour detection in ultrasonography images

Snakes, or active contour models are used extensively for image segmentation in varied fields. However, some major challenges restrict their use in many fields. The authors propose a new inertial snake model, that introduces an inertial effect of the control points into the snake framework. The proposed inertial force along with the first- and second-order continuity forces controls the spline motion through the concavities and also against weak edge forces. This smart force field, added to the inertial energy framework, posses the ability to adaptively reduce its effect near the true edges, so that the energy minimising spline converges into the edges. A greedy snake has been used for computation of the energy minimising spline. The algorithm has been tested on phantoms and ultrasound images as well. It is shown in the results that the proposed algorithm classifies the object from the background class in most of the images perfectly. Ultrasound images of a lower limb artery of an adult woman have been tested with this algorithm, and also extended for motion tracking.     

基于ATmega8的无线智能跳频数码扩音系统

无线扩音系统能解决许多实际工程中的布线和移动使用的难题。无线传输的方式也从传统的U段、V段无线扩音发展到包括红外线、蓝牙和2．4GHz频段在内的无线数字传输方式。数字无线扩音系统可广泛应用在教学、会场、现代办公、家居等领域。文中介绍基于ATmega8的低成本无线智能跳频数码扩音系统设计,利用智能跳频询址技术,可使发射机可更迅速地自动被接收机识别,任意发射机可以匹配任意接收机。     

Time-domain fields exterior to a two-dimensional FDTD space

A transformation algorithm for the near-zone and far-zone fields exterior to a two-dimensional (2-D) finite-difference time-domain (FDTD) field lattice has been developed entirely in the time domain. The fields are found from a surface integration of the convolution of the time derivative of equivalent currents and charges along a contour that encloses the scatterer or radiator of interest. The kernel of the convolution integral has a square-root singularity for which an efficient numerical integration rule is presented. Using this technique, a very accurate solution is obtained; however, convolution integrals are computationally expensive with or without singularities. As an alternative, a rapidly convergent approximate series expansion for the convolution integral is presented, which can be used both in the near and far zone. Results using the new 2-D transform are compared with analytical expressions for the fields generated by a modulated Gaussian pulse for TE and TM line sources. In addition, the 2-D transform solution for the near-zone fields scattered from an open-ended cavity for a TE incident modulated Gaussian pulse plane wave is compared against a full-grid FDTD solution for accuracy and efficiency. The 2-D transform far-zone fields are compared against an alternative technique, which uses a double Fourier transform to perform the convolution in the frequency domain     

Observations of Oceanic Surface-Wind Fields from the Nimbus-7 Microwave Radiometer

Brightness temperatures from the fiIve-frequency (6.6, 10.7, 18, 21, and 37 GHz) dual-polarized scanning multichannel microwave radiometer (SMMR) on Nimbus 7 have been used to obtain surface wind fields over the ocean. The sateilite-derived wind field for 1200Z, February 19, 1979, in the eastern North Pacific has been compared with an operationally generated surface-wind analysis field. Previous point comparisons at selected locations have indicated that satellite winds are accurate to 3 ms-1. The results here, although of a preliminary nature, indicate that SMMR-derived winds may be used to determine large-scale wind fields over the ocean, particularly in areas of strong wind gradients such as found in cyclonic systems.     

Hadamard技术在不均匀场中获取高分辨核磁共振谱的应用

核磁共振(NMR)谱广泛应用于化学,生物和材料科学等领域。分子间多量子相干技术(iMQCs)可以有效地在不均匀磁场中获得高分辨NMR谱,但是该方法获取高分辨谱通常需要较长的数据采集时间,在很大程度上限制了它的应用。Hadamard技术具有时间短和信噪比高的特点,该技术可以较大地缩短不均匀场下采集高分辨NMR谱的时间,因而扩展并增强iMQCs方法在不均匀场下获取高分辨谱的实用性。总结了近几年Hadamard技术结合iMQCs方法在不均匀磁场中获取高分辨NMR谱的基本原理和应用,并对其优缺点做了详细的分析和讨论。     

约束放电激励千瓦级基模CO2激光器

本文研究了约束放电激励千瓦级基模CO2激光器。约束放电激励的思想核心是:利用正交或基本正交的电场或者电磁场在阴极位降区附近形成对带电粒子的捕集阱,由此产生对放电过程中从阴极发出的带电粒子的约束作用从而影响整个气体放电激励过程。     

Immunity tests of implantable cardiac pacemaker against CW and pulsed ELF fields: experimental and numerical results

The aim of the present work is to investigate pacemaker (PMK) immunity against high-level extremely low frequency (typically 50 Hz) magnetic fields that can be found in industrial environment where high power machines operate. To that purpose, a test bench has been set up using a Helmholtz coil for producing extremely low frequency magnetic fields and a trunk simulator rightly fed by cardiac signals. A widely used PMK was tested, and results have been reported, under different operating conditions, for both continuous waves and variously pulsed excitations. A numerical tool has also been developed to analyze the realized test bench, based on a proper discretization of a human trunk simulation and on the construction of an equivalent three-dimensional (3-D) network. Numerical results have showed a good agreement with the experimental results.     

Experimental determination of ion density trapped by electron beam

A new probing technique has been employed to determine the ion density trapped by the potential well of an electron beam as used in microwave tubes, and unexpectedly high values of ionic charge have been found on the axis, the strong space-charge fields of which are neutralised by slow secondary electrons.