电缆渗水缺陷模型及识别波形特征研究

电缆长期处于潮湿地下环境中,外部水分会渗入电缆内部引发绝缘故障,因而电缆渗水缺陷的研究至关重要。为实现电缆渗水缺陷精准定位,构建电缆中间接头及渗水缺陷模型,通过PSCAD搭建电缆传输线路计算模型,根据不同阻抗点特征波形分辨渗水缺陷;对含渗水缺陷电缆进行仿真,根据时域反射(TDR)定位原理确定渗水缺陷位置,并通过渗水缺陷定位试验进行验证。结果表明,TDR检测电缆渗水缺陷时会产生独特的反射波形,该波形与渗水缺陷在电缆中位置无关,但会因渗水量的不同改变其幅值与振荡频率,从而分辨出缺陷,达到精确定位的目的。     

Enhanced Omnidirectional Photovoltaic Performance of Solar Cells Using Multiple‐Discrete‐Layer Tailored‐ and Low‐Refractive Index Anti‐Reflection Coatings

An optimized four‐layer tailored‐ and low‐refractive index anti‐reflection (AR) coating on an inverted metamorphic (IMM) triple‐junction solar cell device is demonstrated. Due to an excellent refractive index matching with the ambient air by using tailored‐ and low‐refractive index nanoporous SiO₂ layers and owing to a multiple‐discrete‐layer design of the AR coating optimized by a genetic algorithm, such a four‐layer AR coating shows excellent broadband and omnidirectional AR characteristics and significantly enhances the omnidirectional photovoltaic performance of IMM solar cell devices. Comparing the photovoltaic performance of an IMM solar cell device with the four‐layer AR coating and an IMM solar cell with the conventional SiO₂/TiO₂ double layer AR coating, the four‐layer AR coating achieves an angle‐of‐incidence (AOI) averaged short‐circuit current density, J_SC, enhancement of 34.4%, whereas the conventional double layer AR coating only achieves an AOI‐averaged J_SC enhancement of 25.3%. The measured reflectance reduction and omnidirectional photovoltaic performance enhancement of the four‐layer AR coating are to our knowledge, the largest ever reported in the literature of solar cell devices.     

RCWA方法设计阶梯形光学生物分子检测探针

设计了一种阶梯形光学生物分子检测探针,并利用严格耦合波分析（RCWA）法计算了此探针的反射光谱的反射效率。模拟结果表明,此探针的反射谱中特定峰值处,探针周围的待测物折射率与探针的入射角间呈线性变化,且探针反射效率与待测物折射率和入射角均符合左半高斯型曲线分布。所以,既可应用入射角来反映待测物折射率的变化,也可利用反射效率的变化反映待测物折射率的变化。基于此研究的方法和结果可广泛应用于生物传感器和生物分析等研究领域。     

精测雷达低仰角测角误差规律的研究

对精测雷达低仰角测角误差规律进行研究,分析了精测雷达回波测量原理,并计算其天线差波束波瓣能量分布情况;研究雷达直射地物回波及地面遮挡对雷达跟踪目标的影响,并与传统多路径效应模型进行对比,得出传统多路径效应模型对雷达低仰角误差的影响并不是主要的;最后结合精测雷达对地物回波的实测数据得出雷达低仰角测角误差的真实变化规律。     

利用全反射原理精确测量棱镜折射率

依据全反射原理和自准直测角法,实现了对棱镜折射率的精确测量。通过使用高准直半导体激光器将激光入射到棱镜内部与空气分界面上,逐步旋转棱镜或改变棱镜的入射角,得到待测棱镜的反射光强随入射角变化曲线。在曲线左侧收尾处出现一个台阶,其反射光强随入射角增大迅速衰减。全反射临界点,对应的入射角为全反射角。用两次自准直测角法精确测量棱镜底角。通过该方法,分别对两块不同棱镜的折射率进行了测量,测量棱镜折射率精度为±1.24×10-4。     

Improving seismic interpretation: a high-contrast approximation to the reflection coefficient of a plane longitudinal wave

Linearized approximations of reflection and transmission coefficients set a foundation for amplitude versus offset（AVO） analysis and inversion in exploration geophysics.However,the weak properties contrast hypothesis of those linearized approximate equations leads to big errors when the two media across the interface vary dramatically.To extend the application of AVO analysis and inversion to high contrast between the properties of the two layers,we derive a novel nonlinearized high-contrast approximation of the PP-wave reflection coefficient,which establishes the direct relationship between PPwave reflection coefficient and P-wave velocities,S-wave velocities and densities across the interface.（A PP wave is a reflected compressional wave from an incident compressional wave（P-wave）.） This novel approximation is derived from the exact reflection coefficient equation with Taylor expansion for the incident angle.Model tests demonstrate that,compared with the reflection coefficients of the linearized approximations,the reflection coefficients of the novel nonlinearized approximate equation agree with those of the exact PP equation better for a high contrast interface with a moderate incident angle.Furthermore,we introduce a nonlinear direct inversion method utilizing the novel reflection coefficient equation as forward solver,to implement the direct inversion for the six parameters including P-wave velocities,S-wave velocities,and densities in the upper and lower layers across the interface.This nonlinear inversion algorithm is able to estimate the inverse of the nonlinear function in terms of model parameters directly rather than in a conventional optimization way.Three examples verified the feasibility and suitability of this novel approximation for a high contrast interface,and we still could estimate the six parameters across the interface reasonably when the parameters in both media across the interface vary about 50%.     

梨树断陷金山地区地震相识别与探讨

松辽盆地梨树断陷金山地区沙河子组、营城组气藏为构造背景下的岩性气藏,地层以砂、泥岩沉积为主,岩性相对单一。为了明确储层特征及分布规律,选用"相面法"对沙河子组、营城组地层进行地震相的分析,共识别出5种主要地震相类型。结合钻井取心岩相、沉积相识别及测井电性特征,利用各主要地震相类型与各沉积相类型相关关系,配合地震反射特征识别,有效地预测了无井区储层的沉积特征及其展布。     

时域反射型分布式光纤传感器性能比较及应用

根据分布式光纤传感技术的发展现状,文章主要介绍了基于时域反射技术和瑞利散射、拉曼散射、布里渊散射的分布式光纤传感器的基本工作原理;比较了目前这几种传感器在测量精度、空间分辨率和测量距离等性能指标及商品化程度等方面的差异;介绍了其在电力工业、石油化工和土木工程等不同社会领域的应用。     

城市包容性发展视角下规划师的角色反思与重塑

在包容性发展的时代要求和包容性规划模式转型的背景下,全面审视、深入反思我国规划师现有的角色和地位,找准理念错位点和价值偏差度,积极促进规划师角色的重塑和转型,具有紧迫性和现实价值。应积极构建适应包容性规划模式的规划师角色建设体系,从理念层面、角色层面和操作层面推进规划师新型多维角色体系的建设,使规划师成为城市发展的经济谋士、价值斗士、信息博士、人权贴士、民生卫士和生态卫士。     

基于线阵CCD的光电玻璃测厚方法研究

玻璃厚度是衡量玻璃制品质量的一项重要性能指标。为了检测平板透明玻璃的厚度,提出了利用线阵CCD传感器作为光电接收器件的玻璃测厚装置,介绍分析了以CCD传感器作为光电接收器件透射式测厚法、单激光反射式测厚法、双激光反射式测厚法3种光路结构原理、以及性能特征。