基于奇异值分解估计点扩散函数的复原算法研究

基于奇异值分解的性质,从离散退化模型出发,采用理想图像奇异值向量的平均能谱理论,得出用奇异值分解来估计点扩散函数的方法,复原过程用逆滤波法来实现。文中采用奇异值累计和函数的二阶导来确定点扩散函数估计过程中的重组阶数R1,三阶导曲线用于去噪的重组阶数R2的选取。用本文方法进行去噪复原实验,与自动选取法进行比较,去噪复原效果较好。     

高速公路不同养护策略的对比分析

以某高速公路长期养护为例,从结合预防性养护规划和单纯矫正性养护规划两个方面出发,建立两种长期的养护计划方案,得到两种养护方案下各路面性能指数的变化趋势.最后在高速公路的使用寿命、经济效益和路用性能三个方面,说明预防性养护在高速公路养护中的优越性,并倡导在高速公路养护中积极运用预防性养护.     

One-dimensional consolidation of double-layered soil with non-Darcian flow described by exponent and threshold gradient

Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian flow law was degenerated to Dary’s law, and the comparison results show that numerical solutions are reliable. Finally, consolidation behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied. The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy’s law.     

Scattering loss in optical waveguide with trapezoidal cross section

To get the scattering loss of the trapezoidal core waveguide, a new analysis model is presented based on the perturbation equivalent method and modified effective-index method. Firstly, the trapezoidal core waveguide is successfully equivalent to the rectangular one with both restricting the same optical field energy by adopting the perturbation method. Then, the equivalent rectangular core waveguide is decomposed into two slab waveguides by employing the modified effective-index method. The trapezoidal core waveguide scattering theory model is established based on the slab waveguide scattering theory. With the sidewalls surface roughness in the range from 0 to 100 nm in the single model trapezodial core waveguide, optical simulation shows excellent agreement with the results from the scattering loss model presented. The relationship between the dimension and side-wall roughness with the scattering loss can be determined in the trapezoidal core waveguide by the scattering loss model.     

中国航天标准化与产品研究院 北京天一正认证中心

北京天一正认证中心(BTCC)成立于1995年,2002年经国家认证认可监督管理委员会(CNCA)批准,中国合格评定国家认可委员会(CNAS)认可,是具备国家认可资格的第三方管理体系认证机构。中心拥有GB/T19001-2008质量管理体系认证、GB/T24001-2004环境管理体系认证、GB/T28001-2001职业健康安全管理体系认证、国家军用标准质量管理体系要求     

空间水处理技术促进健康饮料开发

20世纪90年代中期,如果你在位于美国休斯敦的NASA约翰逊航天中心的大厅里走过,你很可能会碰到约翰逊迈克拖着一大桶新鲜收集的尿液去往实验室。那时,约翰逊迈克正在帮助约翰逊航天中心的科学家进行将废水净化处理成饮用水的技术研究。约翰逊迈克的工作使他获得了1个绰号——"撒尿的人"。直到现在,还有人称呼他这个绰号。尽管饮用回收处理的尿液的想     

非线性抛物方程的指数吸引子

研究了一类非线性抛物方程吸引子的稳定性与其维数。通过低维控制高维的办法向吸引子中添加点,使其具有有限的分形维数与指数吸引率。     

南京市高职教师身体健康与体育锻炼研究

通过对5所高职院校教师的体育锻炼情况及健康状况的调查研究,得出高职院校教师整体缺乏体育锻炼,身体健康状况堪忧的现状。经分析认为造成这一状况的主要原因为高职院校缺乏良好的体育文化氛围,教师体育锻炼没有完善的规章制度,运动场地器材匮乏以及其他制约因素多。并提出具体的改进方法。     

中美产业内贸易分析--基于G-L指数

随着经济全球化的快速发展,国际贸易越来越多地出现在各个国家之间的经济交流中,但是产品同质化这一不可避免的现象不断地在国际贸易中凸显,特别是同产业之间的贸易,这种现象更加突出,这对比较优势理论等传统的国际贸易理论提出了新的挑战。如何解决这一产业内贸易所存在的问题,成为经济专家较多研究的一个重要课题。从产业内贸易的定义入手,运用中美之间贸易产品的数据来分析两国的产业内贸易现状,指出产品同质化的问题所在,并结合该现状提出了中美两国贸易的发展对策与建议,主要是推动产业结构调整,实现产业规模经济;对支柱产业加以扶持与引导,保持国际竞争力;鼓励外商直接投资,学习跨国公司的经验与技术。     

Rytov近似法在闪烁效应中的应用与改进

利用Rytov近似法和湍流大气中高斯波束的传输理论,针对湍流大气中水平传输的主动探测激光,建立了其单程传输到达目标端接收平面的闪烁指数模型,对模型进行改进使其适用于强湍流的大气条件,并对数值仿真的结果进行实验验证。结果表明,改进后的模型更符合实际传输情况,传输距离、湍流强度等因素都会影响闪烁指数的变化,数值模拟与实验测量的结果在变化趋势上有较好的吻合。但由于系统本地噪声、探测器散粒噪声和背景噪声等随机因素的存在,使实测结果略大于数值模拟结果。