大功率LED路灯散热结构技术研究

LED照明产品正在逐渐取代传统的照明灯具成为主流照明产品。本文主要论述了LED灯散热结构的特点,并分析了散热器结构设计与建模。     

碳纤维技术在大功率LED灯具中的应用

随着科学技术的不断进步,LED照明技术越来越成熟,大功率LED灯具在要求具备高散热特性的同时,其轻重量和小体积也成为LED灯具所设计研究的方向。纳米碳纤维材料具有优异的化学物理特性,将其特性加入对LED灯具的设计中,可以有效的解决LED灯具的散热问题,使得大功率的LED灯具真正拥有轻重量、高导热性等性能。     

冷喷涂技术应用于大功率LED散热的研究

LED作为第四代照明光源已被广泛应用于显示、照明等领域,但是由于LED结点温度直接对LED寿命及可靠性造成较大影响,所以如何降低LED结点温度成为现今研究的热点课题。提出了一种利用冷喷涂技术优化LED散热途径的方法,并利用ANSYS软件对其进行了模拟对比,证明采用冷喷涂结合锡焊技术、降低铜基板厚度可有效降低LED散热热阻。     

大功率LED灯散热设计技术

大功率LED灯在发光效率、使用寿命和光输出定向性等技术参数方面的性能均优于常规高压钠灯,因此被广泛应用于多个领域,尤其是在道路照明领域的应用非常普遍。散热性能差是大功率LED非常突出的一个问题,并且灯具的散热性能在一定程度上也会影响灯具的使用寿命,因而要使大功率LED灯具得到更广泛的应用,就必须解决散热问题。本文将在结构、材料等方面提出可行的设计方案,旨在优化大功率LED的散热性能,降低其应用约束条件。     

氮化铝薄膜改善LED散热性能的研究

研究了氮化铝薄膜对LED灯散热情况的影响，并与导热硅脂（Ks609）涂层的散热效果进行了比较，结果表明：导热涂层能加强LED的散热，氮化铝薄膜散热效果优于导热硅脂；对红、白、绿3种颜色LED，相同条件下，散热材料对红色LED的散热效果最好。研究结果为氮化铝薄膜应用于LED散热系统提供了参考数据。     

【INTER NEPCON】LED用封装材料纷纷展出

在“第11届半导体封装技术展”（1月20～22日与第39届INTER NEPCON JAPAN同时举行）上,松下电工、可乐丽以及京瓷化学等相继参考展出了LED用封装材料。LED市场由于LED照明产品和液晶面板背照灯等而迅速扩大。尤其在LED照明产品中,提高LED亮度已经成为技术开发的着力点之一。由此出现高散热性和高反射率的LED底板材料以及高投射率的封装材料等需求,材料厂商相继展出反应出加速应对的姿态。     

新一代超薄LED平板灯概述

<正>LED光源和灯具正在向高亮度、无频闪、高效率、低成本、高性价比、平民化的方向发展。LED照明产品只有广大老百姓用得起、用得好,才能成为家家户户都需要、人人都买得起的消费电子产品;全世界老百姓都能购买,LED照明产品才能成为真正的蓝海产品。LED平板灯因导光板生产技术的进步和LED灯珠亮度的与时俱增,LED平板灯正在向超薄方向发展。例如,昆山诚泰电气股份有限公司新一代超薄节能LED平板灯的总厚度只有7~8mm。超薄的照明灯具与建筑空间很方便融为一体,灯光设计师可以     

LED照明产品光生物安全的分析研究

欧盟ErP指令对定向灯和非定向灯的能效做出规定,由于传统白炽灯无法满足能效要求,2012年底,全部在欧盟市场退市。我国规定2012年10月1日起,禁止进口和销售100瓦及以上普通照明白炽灯。在节能环保大背景下,LED产品开始进入普通照明领域。LED产品一旦应用于普通照明场合,其光生物安全性就显得更为重要。LED曾作为"类激光"产品,纳入IEC 60825-1及系列标准中,     

硅脂导热涂层改善LED散热性能的研究

研究了导热硅脂(KE3493)涂层对水下密闭环境下应用的LED灯散热情况的影响,结果表明,LED系统的集成电路板上加入导热涂层能提高LED系统的散热效率,研究结果为导热涂层应用于LED散热系统提供了参考数据.     

LED标准灯研制的新进展

近二十年来,LED灯逐渐替代白炽灯和多种气体放电光源,成为主要的照明光源。LED灯的发光特性与白炽灯有明显差异,带来了新的计量挑战,LED灯的测量成为光辐射测量领域重点关注的方向。建立基于LED灯的量值传递体系,用LED标准灯代替白炽标准灯,是光度计量史上自1909年以来的重要变革。本文介绍了CCPR和CIE在LED计量领域的战略规划和相关工作,包括LED作为传递标准的国际比对的进展,CIE新的LED参考照明体的制订以及中国计量科学研究院研制的两种LED标准灯的特点和计量特性。最后对LED标准灯的未来发展和应用进行了分析和展望。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.