Comparison of Luminous Efficiency of InGaN-based High-voltage LED with Traditional High Power LED

主要从三个不同角度探究并分析了基于In gA n材料的高压lEd的发光效率优于传统大功率lEd的原因。为了保证实验结论的可靠性,文中所采用的实验样品具有相同的芯片尺寸和材料以及相同的封装结构。经过大量的实验证明,更均匀的电流分布和小芯片间隙的出光,使得高压lEd的发光效率优于传统大功率lEd。结果显示,在相同的1 W输入功率下,高压lEd的发光效率比传统大功率lEd高大约4.5%。The reasons of the luminous efficiency of In Ga N-based high-voltage light-emitting diode(HV-LED)better than that of traditional high power(THP) LED are researched and analyzed from three different aspects.Theexperimental sample with same chip size, material and package structure is adopted to ensure the reliability of ex-periment conclusions.Experiments show that the luminous efficiency of HV-LED is better than that of THP LED foruniformer current distribution and the light from the microchip gap.The results show that the luminous efficiency ofHV-LED is approximately 4.5% higher than that of THP-LED under 1 W input power.国家863项目(2013AA03A107); 福建省产学研重大科技项目(2013H6024); 福建省重点科技项目(2012H0039)资

White LED Phosphor Performance Tested by Spectro320e Spectrometer

我国lEd产业发展非常迅速,稀土钇铝石榴石(yAg)系列荧光粉广泛应用于白光lEd。德国InSTruMEnT SySTEMS公司的SPECTrO320E光谱仪适合光谱的精确测量,文章结合SPECTrO320E和远方公司的PE-5荧光粉激发装置,实现蓝光激发下黄色yAg荧光粉的色品坐标、相对亮度、量子效率等参数精确的测试,研究了仪器在不同的测试条件如暗电流、光电倍增管、密度滤光片等设置的不同,对测试结果的影响,并给出利用本装置测试荧光粉时应该注意的事项。LED industry in china develops rapidly.Yttrium aluminitum garnet(YAG) phosphors are widely applied in white LEDs.The Instrument Systems company's Spectro320e spectrometer is suitable for accurate measurement of the spectrum.It is combined in this paper with the Everfine company's PE-5 phosphor excitation device to achieve the accurate testing of yellow YAG phosphors excited by blue light,such as chromaticity coordinates,relative brightness and quantum efficiency.We also studied the influence of different testing conditions on the results,such as dark current,PMT and density filter.The cautions are provided herewhen using the Spectro320e spectrometer

纪念五四宪法颁布暨全国人民代表大会成立五十周年理论研讨会纪要

今年 9月是五四宪法颁布、全国人民代表大会成立五十周年。五四宪法是新中国的第一部宪法 ,为我国的社会主义民主法制奠定了基础 ,具有划时代的意义。坚持和完善人民代表大会制度 ,是新的历史条件下推进政治体制改革和社会主义政治文明建设的重要内容。基于“以学术表达纪念、以纪念促进学术”的目的 ,中国社会科学院法学研究所于 2 0 0 4年 9月 5日举办了“纪念五四宪法颁布暨全国人民代表大会成立五十周年理论研讨会”。来自全国各地的 70余位代表莅临会议 ,研讨了诸多热点和前沿问题

1978～2008年中国湿地类型变化

分别基于美国陆地卫星(Landsat MSS/TM/ETM+)和中巴资源卫星(CBERS-02B)影像数据,以人工目视解译为主,完成了中国1978～2008年4期(基准年分别为1978,1990,2000和2008年)湿地遥感制图,并进行了大量的室内外验证.在此基础上,对我国湿地现状及近30年来湿地变化进行了初步分析,得到以下主要结论:(ⅰ)截止2008年,中国湿地面积约为324097km2,其中以内陆沼泽(35%)和湖泊湿地(26%)为主.(ⅱ)1978～2008年,中国湿地面积减少了约33%,而人工湿地增加了约122%.过去30年里湿地减少的速度大幅降低,由最初5523km2/a(1978～1990年)降为831km2/a(2000～2008年).(ⅲ)减少的自然湿地(包括滨海湿地和内陆湿地),其类型变化由湿地向非湿地转化的比例逐渐降低.初期(1978～1990年)几乎全部(98%)转换为非湿地;在1990～2000年间减少的自然湿地约有86%转化为非湿地,而在2000～2008年,这一比例下降为77%.(ⅳ)气候变化和农业活动是中国湿地变化的主要驱动因素,湿地变化在中国分为三大不同特征区域,即西部三省/自治区(西藏、新疆和青海)、北部两省/自治区(黑龙江和内蒙古)和其他省市区.其中西部区域尤其是青藏高原,湿地变化的驱动因子以气候增温为主;新疆湿地由于气候增温和农业活动共同作用造成变化不大.北部省/自治区的湿地变化则主要由农业活动引起;而其他省市区的湿地变化几乎完全受控于人类的农业经济活动

Thermal characteristic analysis of LED device and solar cell

近年来，随着半导体行业的飞速发展，太阳能电池和半导体照明的应用也越来越广。目前太阳能电池和大功率LED共同面临的发展瓶颈都是散热问题，发热会严重影响器件的整体性能，最终导致其失效。因此如何准确测量芯片结温、提高器件散热能力是这些半导体器件应用设计中必须着重解决的核心问题。本文开展了太阳能电池和LED器件的热学特性分析，研究内容主要包括以下几个方面： 1. 单晶硅太阳能电池的结温热阻测试分析。结温和热阻是表征太阳能电池热学参数的重要物理量。基于正向电压法，我们分别在没有光照的实验条件和有光照的实验条件下实现了单晶硅太阳能电池的结温热阻测试。同时我们还比较了黑暗条件下和光照条件下的热阻数值并分析...With the development of semiconductor industry, solar cell and light-emitting diodes (LEDs) are more widely applied in recent years. However, it is necessary for these semiconductor devices to dissipate thermal energies into the environment. More and more researchers are interested in enhancing the cooling capacity of those devices. Up to now, it is still a challenge to measure junction temperatur...学位：理学博士院系专业：物理与机电工程学院_无线电物理学号：3312012015386

CLASSIFICATION OF REEF BIOLOGICAL IMAGES OF MARINE RANCH BASED ON DEEP CONVOLUTION NEURAL NETWORK

Status and change of biological resources in marine ranch can be recorded with underwater video.It is necessary to develop image-based biological classification methods to fully develop machine vision technology.We collected underwater videos with different backgrounds of reef,algal bed,and sediment in Yantai and Weihai areas,Shandong,China,and conduct image enhancement,construction of dataset,and application of three classification model.Effects of various color compensation methods were compared in the enhancement of underwater image in marine ranch area,including color compensation based on green channel,contrast limited adaptive histgram equalization,and so on.An image dataset for reef biological classification was established with manual annotation.In total,23211 images were used,from which 11 species of common fish in reef area(including Lateolabrax japonicus,Liza haematocheilus,Sebastes schlegelii etc.),3 species of echinoderm,and 1 species of crab,were recognized and the images processed.Using the PaddlePaddle2.0 and PaddleX development kits,convolutional neural networks AlexNet,MobileNet V3,and ResNet50 were applied to transfer the learning image classification and verify the robustness of the algorithm on underwater images with noise,from which the accuracy of recognition reached 96.64%,94.75%,and 99.23%,respectively.In addition,the ResNet50 model performed better in robustness with Gaussian noise.Therefore,computer vision technology based on deep learning presented a great application potential in biological resources monitoring in marine ranch,and provide new ideas and methods for the monitoring and management of marine ranch in China

上海新国际博览中心钢结构设计

上海新国际博览中心（一期）工程的钢结构是柔性结构体系,形状优美、轻巧,经济效益显著。本文主要就上海新国际博览中心的钢结构设计作简要介绍