基于测度贴近度的电子剪切散斑轮胎检测

本文把测度贴近度的概念引进到电子剪切散斑检测中,提出了一种基于测度贴近度的条纹形成算法。该算法大大地消除了条纹可见度对光照强度的依赖,提高了电子剪切散斑无损检测对工业环境的适应性,并且该算法可以在条纹产生的同时对其进行滤波,减轻了后续工作。本文从数学分析和实验两个角度证实了该算法的以上特点。     

SUPANET的入网控制技术

本文以西南交通大学四川省网络通信技术重点实验室提出的“单物理层用户数据传输平面的体系结构”(SUPA)为背景,通过分析比较现存的各种接纳控制策略和算法,提出了适合SUPA的接纳控制策略和算法。     

DEH控制系统在125 MW汽轮机上的应用

介绍了江西贵溪发电厂国产125MW机组调速系统的低压透平油纯电调改造的意义、方案选择及各相关系统的改造内容。改造后机组的运行情况良好，低压透平油纯电调改造，具有简单、实用、经济、可靠的特点，对同类型机组的技术改造具有借鉴意义。     

Residual generation for fault diagnosis in linear time-varying systems

A residual generation method for fault diagnosis in deterministic and stochastic linear time-varying systems is proposed in this note. Based on appropriate assumptions on the monitored faults and on some persistent excitation condition, it enables complete diagnosis of any number of faults, regardless of the number of output sensors. In order to generate residuals for fault diagnosis, part of the possible faults are estimated with a recently developed technique of adaptive observer. The sensitivity of the residuals to the monitored faults is rigorously analyzed, as well as their insensitivity to the faults to be ignored.     

Electrical Properties and Electroluminescence of 4H-SiC p-n Junction Diodes

Homoepitaxial growth of 4H-SiC on off-oriented Si-face(0001 ) substrates was performed by using the step-controlled epitaxy technique in a newly developed low-pressure hot-wall CVD (LP-HWCVD) system with a horizontal aircooled quartz tube at around 1500 ℃and 1.33 × 104 Pa by employing SiH4 C2H4 H2. In-situ doping during growth was carried out by adding NH3 gas into the precursor gases. It was shown that the maximum Hall mobility of the undoped 4H-SiC epilayers at room temperature is about 430 cm2 ·V -1 ·s -1 with a carrier concentration of ～ 1016 cm-3 and the highest carrier concentration of the N-doped 4H-SiC epilayer obtained at NH3 flow rate of 3 sccm is about 2.7 × 1021 cm-3 with a mobility of 0.75 cm2 ·V -1 ·S -1. SiC p-n junctions were obtained by epitaxially growing N-doped 4H-SiC epilayers on Aldoped 4H-SiC substrates. The C-V characteristics of the diodes were linear in the 1/C3-V coordinates indicating that the obtained p-n junctions were graded with a built-in voltage of 2.7 eV. The room temperature electroluminescence spectra of 4H-SiC p-n junctions are studied as a function of forward current. The D-A pair recombination due to nitrogen donors and the unintentional, deep boron center is dominant at low forward bias, while the D-A pair recombination due to nitrogen donors and aluminum acceptors are dominant at higher forward biases. The p-n junctions could operate at temperature of up to 400 ℃, which provides a potential for high-temperature applications.     

Challenges and R&D opportunities of smart distribution grids in China

In this paper, 5 investigations on the current states of power distribution grids in China have been introduced that cover the surveys of the practical distribution asset utilization, the simultaneity factor of feeder loading, the load compositions and characteristics, the urban reliability and the integration of distributed generations of renewable resources. Based on the survey results in the investigations, 12 Facts are clearly presented. It shows that the challenges to modernize the distribution grids in China are to improve the asset utilization rates, the electricity efficiencies and the reliability of distribution systems, as well as to integrate increasing amount of variable distributed renewable resources. Furthermore based on the challenges, 8 R&D opportunities have been identified.     

电测技术在人体骨骼力学性能分析中的应用

用电测实验应力分析方法,对人体管状长骨的力学性质,以及骨折的钢板皮外固定治疗中的力学问题,进行测量与分析。其结果对于推进力学理论在医学方面的应用,以及临床治疗骨折,具有实用价值。     

湖南省土壤中天然放射性核素含量调查研究

本文报道湖南省土壤中天然放射性核素含量的调查结果。布点方法与环境陆地γ辐射剂量率调查相同,全省共布25×25km 网格点309个,土类加密点5个,特殊加密点7个,共采集土壤样品321个。土壤样品中天然放射性核素含量的测定采用放化分析方法。调查结果表明,湖南省土壤中~(23(?))U、~(232)Th、~(226)Ra 和~(40)K 含量按样品数的加权均值分别为48.05、54.82、59.36和447.75Bq/kg。零陵地区土壤中~(238)U、~(232)Th 和~(226)Ra 含量最高,郴州地区次之,湘西自治州地区居三。湖南省6类主要土壤中~(40)含量较为接近,而红壤中~(238)U、~(232)Th 和~(226)Ra 含量较高。     

矿热炉把持器的传热分析

以矿热炉电极把持器的传热计算为核心,研究把持器的结构设计和参数选用。通过对冷却水流量、壁面厚度、水垢厚度、烟气温度等影响因素的研究,结合把持器传热边界条件,分析了在不同参数条件下传热变化趋势,为电极把持器的设计和应用提供了参考依据。     

微机控制的感应电动机特性测试系统

采用单片机作为下位机,PC机作为上位机,联合组成了感应电动机特性的微机测试系统。单片机对被测电量波形进行同步采样,对被测电机的运行状态进行控制。PC机控制单片机的运行,对测量数据进行快速处理,打印试验报告,绘制图形曲线,实现了测试过程的自动化。