And the results of calculation and numerical simulation indicate, without increasing the intrinsic collector - junction area of power devices, collector - combed structure helps to raise the intrinsic heat - dissipating area and base ' s perimeter, improve heat - dissipating method of each cell of the chip, enhance the distribution uniformity of junction temperature and current of each cell of the chip, reduce the thermal resistance and raise the dissipation power pd and output power p0, fairly well relax the contradiction among frequency, out - put power and dissipation power of the devices, and further improve the devices " property against second breakdown
而計算分析和二維數值模擬分析結果表明:梳狀集電結(基區)結構在不增加器件本徵集電結面積的條件下,增大了器件的本徵散
熱面積和基區周長,改進了每個子器件單元內的散
熱方式,提高了單元內結溫和電流分佈的均勻性,降低了器件的
熱阻,增大了器件的耗散功率和輸出功率,較好地緩解了目前傳統結構中頻率與功率、功耗的矛盾,並有利於改善器件抗二次擊穿的性能。
The heating response curves of temperature rise and thermal resistance of semiconductor power emitting - lighting diodes are obtained according to electrical methods
摘要通過電學測量方法得到了半導體功率發光二極體溫升與
熱阻的加
熱響應曲線。
Termal performance of buildings - determination of thermal resistance by hot box method using heat flow meter - masonry ; german version en 1934 : 1998
建築物
熱性能.
熱阻測量.
熱流計
熱箱法.砌墻
Of the currently available coolers for electronic products with a high heat flux, microchannel heat sinks have been proved to be able to provide the best heat transfer performance and are one of the most promising coolers. the manifold microchannel ( mmc ) heat sink has many advantages such as low thermal resistance, compact structure, little amount of coolant, low flow rate, uniform temperature distribution along the flow direction and many others, so it is able to provide the best heat transfer performance : lowering the maxmal temperature and the temperature difference
在目前高
熱通量電子產品冷卻器中,微通道
熱沉已被證實是傳
熱性能最佳且最具應用潛力的冷卻方式之一,而歧管式微通道
熱沉因具有低
熱阻、結構緊湊、所需冷卻液量小、沿流動方向溫度分佈均勻等優點則成為減小電子元器件換
熱表面最高溫度、降低溫度變化的一種有效方法。
The optimum inclination angle is between 15 ~ 20, the length of thermosyphon will not change the phase - change heat transfer coefficient of the evaporation section and the condensation, which will enlarge heat transfer area of thermosyphon and increase the heat exchange capacity. the head - on speed of wind only stranger the heat transfer of the evaporation section and the condensation section. the experiment shows that the mathematic model closely fits to the thermosyphon, moreover, the one key to resolve the thermosyphon effect lies in decreasing the thermoresistance of evaporating section and condensation section. this study can provide directions and experience in the future research
傾斜角越大,
熱虹吸管總
熱阻越大,最佳傾角在15 20之間;充液率過多或過少都會對傳
熱性能產生不利影響,對于本實驗採用的1 . 75m 、 2m 、 2 . 5m 、 3m
熱虹吸管,最佳充液率在20 % 35 %之間;管長對傳
熱也有影響,管長不改變
熱虹吸管蒸發段和冷凝段的換
熱系數,只增加了
熱虹吸管的換
熱面積,增大換
熱量;迎面風速的大小,起到強化
熱虹吸管蒸發段和冷凝段換
熱的目的。
Thermal contact resistance is calculated by fem. the triangular model is considered more precise when its control angle equals 30 and an approximate formula is provided for calculation of the thermal contact resistance by comparing computation models
本文採用有限單元法數值計算接觸
熱阻,提出控制角為30的三角形模型具有較高的精度,給出接觸
熱阻的近似計算公式,並分析了表面粗糙度對接觸
熱阻的影響。
As we all know, occupants " thermal sense is mainly dependent on the six factors : inside air temperature, humidity, air velocity, mean radiant temperature, clothing and metabolism rate. the traditional hvac control system, neglecting other factors concerned with human comfort, only considering the inside air temperature and air humidity and indirectly impacting on occupants by the two parameters control, cannot satisfy the comfort requirement of occupants and is energy wasting as well
傳統的空調控制系統以室內空氣的溫濕度作為控制對象,而實際上影響人體
熱舒適的因素不僅包括溫度與濕度,還有風速、平均輻射溫度、人體的衣著
熱阻和人體的新陳代謝率,人體對環境的冷
熱感受是這些因素綜合作用的結果,因此在很多時候系統並不能滿足人體對
熱舒適的需要而且節能性較差。
The theory of interface of two - phase fluid id used to analyze the role of the interfacial heat transfer resistance in cond ensation process, it shows that the interfacial heat transfer resistance can not be ignored under such a vacuum condition, and the effect on heat transfer process becomes declined with the increasing of vapor pressure
應用兩相界面理論分析了汽液界面
熱阻在水平管內低壓蒸汽冷凝過程中所起的作用,發現實驗范圍內汽液界面
熱阻不可忽略,且其對冷凝傳
熱過程的影響隨蒸汽壓力的增大而減弱。
In this paper, the thermal insulation of cotton fabrics under wet condition is studied, that helps better understand the variation of thermal insulation of clothing when human body is sweating
摘要對潤濕狀態下織物
熱阻的研究,能更好的了解人體顯性出汗后服裝
熱阻的變化。
The developed extinguishing material possesses excellent properties of heat insulation and vapor seal, and the method shows satisfactory extinguishing effects on the oil surface on the basis of small - scale oil tanks
熱輻射試驗和小型油罐滅火試驗證明,該材料具有良好的液面隔熱阻氣性能和滅火效果,適合撲救任何油池火災。