A study of test system for thermal resistance of IGBT

This paper is the first part of a two part study into the pressure-flow characteristics of a range of microchannels measured over a range of typical Reynolds numbers. Here the manufacture of the channels and their resulting quality is addressed. The target application is silicon cooling. Wet Etching, Deep Reactive Ion Etching (DRIE) and Precision Sawing have been used to create microchannels in silicon and thermoset plastic. Anodic bonding has been used to bond covers onto the DRIE and Wet Etched channels. Wet etching a (100) silicon wafer using a KOH solution produced trapezoidal channels of width 577 μm and height 413μm. DRIE using the Bosch process produced rectangular channels in (100) silicon of width 304μm and height 332μm. Mechanical sawing using a Disco Dicing Saw produced near rectangular channels in both silicon and plastic. The silicon channels were 52μm wide and 423μm deep, and the plastic channels were 203μm wide by 344 or 382μm deep. Channel dimensions were measured using a scanning electron microscope. Silicon was the main material chosen, since it is possible to cut cooling channels directly into one side of a silicon device, while the electronic parts are deposited on the other, giving effective cooling with minimal thermal resistance. The plastics chosen are commonly used to encapsulate electronic packages and will also be in close proximity to the heat producing regions of the device it protects. Embossed channels on a plastic encapsulant also potentially offer a low cost mass producible means of cooling electronic devices with a low overall thermal resistance. A glass cover was anodically bonded over the silicon channels to prevent channel to channel leakage and provide optical access. The plastic channels were also covered by a glass slide, bonded in position using SU8 Photoresist spun on the glass. This paper demonstrates the feasibility of producing relatively large microchannels in two materials by three methods. Part two of this paper will describe the modular flow test system and analyze the flow friction through the channels.

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Study on Cooling Effect and Pavement Performance of Thermal-Resistant Asphalt Mixture

Advances in Materials Science and Engineering ◽

10.1155/2018/6107656 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 15

Author(s):

Jiarong Wang ◽

Zhengqi Zhang ◽

Datong Guo ◽

Cheng Xu ◽

Ke Zhang

Keyword(s):

Thermal Conductivity ◽

Thermal Resistance ◽

Asphalt Pavement ◽

Asphalt Mixture ◽

Test System ◽

Test Methods ◽

Cooling Effect ◽

Pavement Performance ◽

Fine Aggregate ◽

Low Temperature Cracking

To reduce the temperature of asphalt pavement and improve the antirutting performance of asphalt mixture, a thermal-resistant asphalt mixture (TRAM) was produced, in which a certain proportion of mineral aggregate was replaced by ceramic (CE) or floating beads (FB) featuring low thermal conductivity. Firstly, a parallel plate test was developed to test the thermal conductivity of asphalt mixture added with different thermal-resistant materials. Secondly, the illumination test system was designed to study the visual cooling effect of different TRAM by imitating the natural environment. Finally, the effect of different thermal-resistant materials on asphalt pavement performance was evaluated. The results show that the addition of thermal-resistant materials can reduce the thermal conductivity and the temperature of asphalt mixture. The cooling effect of CE75 and CE100 (coarse aggregate substituted by 75% and 100% CE, respectively) is superior to other aggregates. The temperature reduction rates of CE75 and CE100 reache 6.6°C and 6.8°C, respectively. For FB50 and FB75 (fine aggregate substituted with 50 and 75% FB, respectively), the cooling effect of them reaches 3.9°C and 4.5°C, respectively. In addition, the CE and FB can improve the antirutting performance of asphalt mixture by reducing the temperature inside the pavement. The high-temperature performance of CE75 and FB75 is the best. With the increase of thermal resistance materials, the low-temperature cracking resistance of asphalt mixture decreases gradually. The failure strain of mixture added with 100% thermal resistance materials is close to the lower limit of Chinese specification. The water stability of different TRAM changes with various test methods. Taking into account the results of pavement performance and the cooling effect, the substitution proportion of CE and FB for TRAM is proposed as 50%∼75%, respectively.

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Heat Transfer Enhancement in Gravity Heat Pipes Using AAO Nanostructure Generated on Condenser Section Inner Surface

Processes ◽

10.3390/pr9101827 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1827

Author(s):

Chun-Ching Kuo ◽

Huei Chu Weng

Keyword(s):

Heat Transfer ◽

Thermal Resistance ◽

Temperature Difference ◽

Performance Test ◽

Heat Transfer Performance ◽

Heat Pipes ◽

Test System ◽

Transfer Performance ◽

Condenser Section ◽

Inner Surface

This study mainly focuses on the influence of anodic aluminum oxide (AAO) nanostructure generated on condenser section inner surface on the heat transfer performance of gravity heat pipes. AAO nanotubes were first grown by anodizing the inner wall surface of the condenser section of aluminum alloy gravity heat pipes through different anodizing voltages and treatment times. The nanostructure effect on the temperature distribution and overall thermal resistance was then investigated by using a thermal performance test system under different input heat powers. The experimental results showed that the generation of AAO nanostructure on the inner surface significantly enhances heat transfer performance; that is, the temperature difference between the evaporator and condenser sections and overall thermal resistance are reduced. Such an effect can be more significant in the case of a lower heat source. The percentage decreases in temperature difference and overall thermal resistance can be reduced by up to 58.83% and 58.79%, respectively, compared to the unprocessed heat pipe.

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Thermal Performances Analysis of Microelectronic Chip Cooling System with Thermoelectric Components

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.216.128 ◽

2011 ◽

Vol 216 ◽

pp. 128-133 ◽

Cited By ~ 1

Author(s):

Chang Hong Wang ◽

Jiang Yun Zhang ◽

Jin Huang

Keyword(s):

Thermal Resistance ◽

Cooling System ◽

Dominant Role ◽

Test System ◽

Peltier Effect ◽

Thermoelectric Cooling ◽

Analysis Model ◽

Total Thermal Resistance ◽

Chip Cooling ◽

Operating Current

The microelectronic chip thermoelectric cooling equipment and its test system have been developed for the deficiency of the conventional cooling technologies in this paper. The thermal resistance analysis model was applied in research the heat transfer process of the microelectronic chip cooling system and its characteristics. The results show that: When the thermoelectric cooling (TEC) system is in normal operating condition,the Peltier effect is the dominant role in the thermoelectric cooling process despite the opposite actions of the Joule and Fourier effects. The thermal resistance of TEC, which is Q2, decreases when the operating current (I) increases. For the different chip power, there is an optimum current (Iopt) making the interface thermal resistance between chip and TEC minimum (Q1). Q1can obtain the minimum 0.465°C·W-1 when the chip power is 25W and Iopt is 2.4A. The total thermal resistance (Qtotal) firstly decreases and then increases with the increase of operating current. There is an optimum current which allows the total thermal resistance is smallest. Qtotal may obtain the minimum value 0.672°C·W-1 when the chip power is 25W and Iopt is 2.4A. Furthermore, Qtotal Iopt both increase by the chip power.

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Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128900 ◽

1987 ◽

Vol 45 ◽

pp. 924-925

Author(s):

F. A. Durum ◽

R. G. Goldman ◽

T. J. Bolling ◽

M. F. Miller

Keyword(s):

Inclusion Bodies ◽

Large Scale ◽

Recombinant Dna ◽

Test System ◽

Cell Protein ◽

Gram Negative Bacteria ◽

Cytoplasmic Inclusions ◽

Isolation And Purification ◽

E Coli ◽

Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

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Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

American Journal of Audiology ◽

10.1044/1059-0889.0104.52 ◽

1992 ◽

Vol 1 (4) ◽

pp. 52-55 ◽

Cited By ~ 4

Author(s):

Gail L. MacLean ◽

Andrew Stuart ◽

Robert Stenstrom

Keyword(s):

High Frequency ◽

Sound Pressure ◽

Low Frequency ◽

Test System ◽

Output Frequency ◽

Frequency Effects ◽

Adult Men ◽

Frequency Responses ◽

Significant Difference ◽

Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

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