LED散热模块总热阻测量实验系统开发

为满足LED散热课程实验教学环节中学生技能培养的需要,以6颗LED组装成的散热模块为实验对象,并将单颗LED在SSP8810-S型测试系统中测得的数据拟合,得到不同驱动电流下发热功率、参考点温度分别与芯片结温的关系式,以此为工作原理,设计并搭建出一套可实现LED散热模块总热阻测量的学生实验系统。该实验系统操作简单,成本低廉,能通过改变LED驱动电流、空气流速和环境温度等关键影响因素,获取LED结温和总热阻的变化趋势,且实验数据有效可靠,展现的客观规律有助于学生对散热设计与分析方法的学习和理解,值得在LED散热相关课程的实验教学中推广使用。     

新型热管式大功率LED路灯散热器的研制

基于目前制造半导体的技术,LED输入功率中绝大多数的能量转化为热能,大约只有15%的能量转化为光能,因此必须提高LED的散热能力以保证LED的正常使用.研制了一种新型热管式大功率LED路灯散热器,该散热器的方向垂直于基板,且开设了通孔以便于液体工质在金属薄片的相邻缝隙间流通,以利于降低芯片的结温.通过对LED路灯样品温度测试实验表明安装有新型热管式散热器的LED路灯,温度变化平稳,测量到的最高温度为41.2℃.     

利用Flotherm对大功率LED封装的热分析

对某一大功率发光二极管(LED)器件的封装结构进行等效热阻网络分析,并利用Rotherm软件对该LED进行热分析,比较了采用纯银、纯铜、纯铝等不同材料作为热沉对LED器件的散热性能的影响,结果表明采用纯银热沉散热效果最好.     

大功率LED散热技术探讨

LED由于具有体积小、工作电压低、寿命长、节能等优点,必然在众多光源中占据优势地位,但散热问题是限制其发展的瓶颈;首先对大功率LED封装总的热阻进行了分析,确定了影响大功率LED封装散热的因素;然后对国内外LED最新散热技术的进展进行了比较.     

顺排翅柱结构散热器在 LED 集渔灯上的应用研究

采用Fluent有限元分析软件进行模拟分析,研究了大功率LED集渔灯的顺排翅柱结构水冷散热器翅柱之间距与散热性能、均匀性的关系。在此基础上,提出了一种混合结构达到均匀性与散热性能兼顾的方案;同时研究了流速与散热器厚度的关系,以达到散热器的轻型化目的。     

一种笔记本电脑水冷散热系统设计及散热效果

设计了某型号笔记本电脑水冷散热系统,通过热力学理论散热模拟计算设计制造出的换热器散热效率为90%,水冷散热系统的峰值温度为70℃。用鲁大师软件监测了计算机中央处理器(CPU)和显卡的温度,比较分析了其散热效果。结果表明:在大型游戏连续运行2 h内,水冷散热系统下,CPU温度最高达75℃,显卡温度达到80℃;风冷散热系统下,显卡和CPU达到80℃左右,相对于水冷散热系统,散热较慢;而在大型单机游戏运行结束时,水冷系统下显卡和CPU突降为50℃,在非大型游戏电脑正常工作状态下,显卡和CPU温度维持在50℃左右。而风冷散热系统下大型游戏运行2 h结束90 min后,CPU温度降至55℃左右,显卡温度降至50℃以下。     

试提高辐射散热在LED路灯中的降温作用

通过借鉴光学增透膜的设计方法,提出一种在辐射散热涂层和LED路灯基板之间的增热层设计,并讨论镀膜的方法及可能遇到的问题,以提高辐射散热在LED路灯中的降温作用。     

摩擦片背板精冲的三维数值模拟及参数优化

针对精冲三维数值模拟的局限性,采用有限元软件Deform-3D建立摩擦片背板的三维精冲模型。根据Normalized Cockroft＆Latham断裂准则,分析了成形过程中的静水应力、金属速度流动分布和发展趋势。通过数值模拟获得最佳冲裁间隙值为厚度的0.6%,为提高精冲件质量提供了依据。     

LED路灯散热器高辐射散热涂层材料的选择

借鉴光学增透膜的概念,提出在辐射散热涂层和LED路灯基板之间增加一层增热层,称之为辐射增透层,从而可以提高辐射散热在LED路灯中的降温作用。文章通过对薄膜透射光谱对增热层可能选用的材料进行了对比分析,选出较合适加工辐射增透层的材料。     

汽车中冷气散热仿真研究

为了研究中冷器散热性能,采用Space Claim建立中冷器模型,运用mesh进行网格划分,通过Fluent软件进行仿真研究.分析了汽车中冷器内部流场分布情况,对不同进口温度、进口速度、翅片厚度以及翅片数量工况下散热性能进行了研究.结果表明:当中冷器的进口温度相同时,其进口速度越小,散热效果越好;当中冷器的进口速度相同时,其进口温度越小,散热效果越好.当中冷器的翅片厚度以及翅片数量越大时,散热效果也更好.计算结果为中冷器的设计提供了理论依据.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.