54 research outputs found

    The transformation of the vehicle electrical test sets based on CAN bus technology

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    Can-Bus总线技术是“控制器局域网总线技术(ControllerAreaNetwork-BUS)”的简称,它具有极强的抗干扰和纠错能力,该技术运用于汽车上,可以减少汽车车体内线束和控制器的接口数量,避免了过多线束存在的互相干涉、磨损等隐患,降低了汽车电气系统的故障发生率,使汽车的防盗性、安全性都得到了较大幅度提升。就目前而言,Can-Bus总线技术在中、高档轿车以及客车上应用广泛。 目前国内的全车电器教学实验台,各电器之间采用点对点连接方式进行数据传输,该种实验台可以演示各电器工作原理并通过故障设置系统来进行排故练习。 本文针对某款全车电器教学实验台做改造,将电器之间的点对点连接方式改...Can-Bus bus technology is " controller area network bus technology ( Controller Area Network-BUS ) " for short, has the strong anti-interference and error correction capability, the technology used in the car, can reduce the number of automobile wiring harness and controller interface, and avoid the mutual interference, wear much hidden trouble of wiring harness existing, reduce failure of automob...学位:工程硕士院系专业:物理与机电工程学院机电工程系_机械工程学号:X200918200

    手机媒体背景下高校思想政治教育工作模式初探

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    伴随3g网络在中国的强势推广,如今手机已经成为我国网民第一大上网终端。高校大学生手机网民增长迅速,对高校思想政治教育工作提出新挑战和新要求。本文在对高校大学生进行抽样调查的基础上,分析了高校大学生手机上网行为及其特征,初步提出手机媒体背景下高校思想政治教育的应对策略。福建省高校思想政治教育研究会课题(JBS10003)成

    海西对台光电产业产学研合作现状及趋势

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    海峡西岸对台光电产业产学研合作是两岸科技界高度重视的一项重点工程,在两岸政策的引导下,在市场需求及产业界、学术界的共同推动下,合作领域越发广泛,合作交流的形式和渠道不断拓宽,带动两岸科技进步及经济发展。本文着重分析了两岸光电产业的发展现状和海西对台光电产业产学研合作现状、趋势,阐明了合作机制及相应的目标与重点、方式等。在此基础上提出了海峡西岸经济区对台光电产业合作的策略及对两岸光电产业良性发展的建议。福建省科技计划项目(2016R0091);福建省高等教育教学改革研究项目(JAS151398)

    周期性机械拉伸对表皮干细胞分化及生物学效应的影响

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    背景:表皮干细胞是创面愈合过程中的重要细胞成分之一,表皮干细胞分布在基底层,约占基底层细胞的1%-10%,对皮肤的张力有较高的感应能力,其细胞表面有高水平的integrin-beta1表达,因而integrin-beta1高表达被认为是KSC分子标志之一,同时也是表皮干细胞对皮肤张力的感应器。。整合素尤其是整

    基于词向量空间的大规模中文语义网络构建与复杂性分析

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    当前对于汉语语义层次的语言网络研究方法仅限于静态词典生成以及人工手动生成两种方法,具有很大的局限性。对此,该文从大规模语料库生成的语义空间出发,结合语义空间丰富的语义信息和义类词典资源,提出一种新颖的基于分布语义的语义网络构建策略,并在此基础上探究了由不同性质的语义空间所构建的语义网络的统计特性。相比前人的方法,该文提出的方法优势在于无需依赖人工标注,支持大规模动态语料的网络自动构建。实验结果表明,语义网络具有复杂网络两个典型的特性:小世界效应和无标度特性。此外,由于语义网络描述的是词之间最为本质的语义关系,与不同文体中的措辞、使用习惯、风格等不存在直接的关系,因此当语义网络节点到达一定规模时,语义网络的某些统计特性可能会趋于一致

    Testing System of Phosphor Excited by Blue LED Based on Integral Sphere

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    为尽可能反映荧光粉在实际工作条件下的发光性质,准确测量荧光粉的发光性能,提出了一种基于积分球的荧光粉发光性能测试系统。该系统采用蓝光lEd作为激发光源,配置有TEC控温系统对光源有效实施控温,可提供持续稳定的激发荧光粉发光。采用出光筒控制光源方向和积分球收集光线,能有效防止能量损失,提高测试的精确性。通过实验得到了不同强度蓝光激发下的荧光粉光谱功率分布以及发光效能、量子效率、光转换效率等参数的变化规律。随着驱动电流的增大,由于蓝光芯片内量子限制斯塔克效应,从而导致蓝光峰值波长出现小幅度的蓝移。三种效率在小电流下基本呈线性下降趋势,且在大电流下趋于平缓。实验结果表明,该系统及方法可以有效地评价实际lEd芯片工作状态下的荧光粉发光性能。A testing system for phosphor luminous characteristics based on integral sphere is proposed so as to show luminous characteristics of phosphor at actual operation circumstances and measure its luminous characteristics accurately.Blue LED is used as an excited source in the system.TEC temperature control system is used to control the temperature of the source effectively.And continuous and stable excited light is provided to excite phosphor illumining.Energy loss is prevented effectively and testing accuracy is enhanced for the direction of source controlled by a light tube and light ray collected by integral sphere.Based on experiments,spectrum power distributions of phosphor excited by blue light with difference light strength and variation rules of parameters such as luminous efficiency,quantum efficiency and light conversion efficiency are got.With the increasing of driving current,a small blue shift appears in blue light peak wavelength for quantum confined Stark effect in blue light chip.Three kinds of efficiency almost show linear decline trend at low current and then approach to constant at high current.Experimental results show that luminous characteristics of phosphor on real LED chip at operation state can be evaluated effectively by the system and method.国家自然科学基金项目(11104230); 福建省重点科技项目(2011H6025;2012H0039

    White LED Phosphor Performance Tested by Spectro320e Spectrometer

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    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

    Thermal characteristic analysis of high-power LEDs by structure functions

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    运用电学法测量功率型lEd冷却瞬态温度曲线,通过数学方法将其转化为积分和微分结构函数来分析器件各区域的热阻和热容,结果发现,各层材料的测量值与理论值基本一致。1μS的瞬态数据采集精度和高的重复性保证了实验结果的准确性和可靠性,运用这种方法比较了3种不同金属芯印刷电路板(MCPCb)对功率型lEd的散热效果,贝格斯Al基板散热性能最好,AnTAl基板次之,普通Al基板最差。研究表明,利用结构函数分析功率型lEd的热特性是一种强有力的方法。The cooling transient temperature curves of high-power LEDs are measured by electritical method.The cumulative and differential structure functions are extracted from these curves to analyse thermal resistances and thermal capacitances of all regimes of high-power LEDs with numeric computational method.It is found out that calculated and measured values of various materials are essentially conformable.The sampling resolution of 1 μs of transient data and high repetition assure the veracity and reliability of experimental result.Subsequently,thermal conduction capabilities of three different metal core printed circuit boards(MCPCBs) with high-power LEDs are compared by this method,and it is discovered that bergquist′s MCPCB has the best thermal conduction capability,ANT′s MCPCB takes second place,and the common MCPCB is the worst.So the structure functions are powerful tools for thermal characteristic analysis of high-power LEDs.国家“863”计划资助项目(2006AA03A175);福建省科技项目(2006H0092;2008J0030);厦门市重大专项资助项目(3502Z20061004

    Design of a Temperature-Controlled Test System for Luminous Intensity Spatial Distribution Characteristics of High Power LED

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    发光二极管(lEd)的光强空间分布特性决定了它能否满足特定场合的应用。大功率lEd由于发热量大,其绝对光强空间分布(lISd)的测试也必须在特定热沉温度下进行才能得到准确可靠的结果。设计了一个可对大功率lEd进行热沉温度控制且快速实现lISd自动测试的系统。该自动测试系统基于lEdgOn-100测角光度计及其高精度的二维旋转台,配合测试适配器、温度控制器、光度探头、kEITHlEy 2400源表和测试软件组成。测试软件基于dElPHI程序语言开发。在控温条件下,该lISd自动测试系统稳定可靠,测试时间大大缩短,测试结果实时直观。利用该自动测试系统对具有朗伯型和蝙蝠翼型两大lISd类型的lEd进行测试,获得它们的二维lISd和三维lISd。实验结果表明:随着热沉温度的增加,光强绝对值下降,而相对lISd却不变。Characteristics of the luminous intensity spatial distribution(LISD) of light emitting diodes(LEDs) are capable of determining whether these devices can be applied on specific occasions.The absolute LISD of high power LED can be accurately measured only when LED is fixed at a specific heat- sink temperature because of the LED′s large heat-generating capacity.In this study, an automatic test system based on LEDGON-100 goniophotometer and the meter′s high-precision two-dimensional(2D) revolving platform, is designed.In addition, it comprises of a test adapter, a temperature controller, a photometer head, a Keithley 2400 source meter, and an in-house-developed software package.This assembly can both control heat-sink temperatures and measure the LISD characteristics rapidly for high- power LEDs.The software is developed using Delphi programming language.The test system is stable and reliable.The test time is greatly reduced and measurements are instantly displayed.Two general types of LEDs, Lambertian type and batwing type, are measured by the system to obtain their 2D and three-dimensional(3D) LISDs.Experimental results show that the absolute luminous intensity decreases as the heat-sink temperature increases.However, the relative LISDs are the same under different heat-sink temperatures.国家自然科学基金(11104230); 福建省重大科技项目(2011H6025;2012H0039

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

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    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
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