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Thermal resistance matrix representation of thermal effects and thermal design of microwave power HBTs with two-dimensional array layout
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作者 陈蕊 金冬月 +5 位作者 张万荣 王利凡 郭斌 陈虎 殷凌寒 贾晓雪 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第9期373-380,共8页
Based on the thermal network of the two-dimensional heterojunction bipolar transistors(HBTs) array, the thermal resistance matrix is presented, including the self-heating thermal resistance and thermal coupling resist... Based on the thermal network of the two-dimensional heterojunction bipolar transistors(HBTs) array, the thermal resistance matrix is presented, including the self-heating thermal resistance and thermal coupling resistance to describe the self-heating and thermal coupling effects, respectively.For HBT cells along the emitter length direction, the thermal coupling resistance is far smaller than the self-heating thermal resistance, and the peak junction temperature is mainly determined by the self-heating thermal resistance.However, the thermal coupling resistance is in the same order with the self-heating thermal resistance for HBT cells along the emitter width direction.Furthermore, the dependence of the thermal resistance matrix on cell spacing along the emitter length direction and cell spacing along the emitter width direction is also investigated, respectively.It is shown that the moderate increase of cell spacings along the emitter length direction and the emitter width direction could effectively lower the self-heating thermal resistance and thermal coupling resistance,and hence the peak junction temperature is decreased, which sheds light on adopting a two-dimensional non-uniform cell spacing layout to improve the uneven temperature distribution.By taking a 2 × 6 HBTs array for example, a twodimensional non-uniform cell spacing layout is designed, which can effectively lower the peak junction temperature and reduce the non-uniformity of the dissipated power.For the HBTs array with optimized layout, the high power-handling capability and thermal dissipation capability are kept when the bias voltage increases. 展开更多
关键词 HETEROJUNCTION BIPOLAR transistors(HBTs) ARRAY THERMAL effects THERMAL resistance matrix THERMAL design
Advances on strategies for searching for next generation thermal barrier coating materials
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作者 Bin Liu Yuchen Liu +5 位作者 Changhua Zhu Huimin Xiang Hongfei Chen Luchao Sun Yanfeng Gao Yanchun Zhou 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第5期833-851,共19页
Thermal barrier coating(TBC) materials play important roles in gas turbine engines to protect the Nibased super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, larg... Thermal barrier coating(TBC) materials play important roles in gas turbine engines to protect the Nibased super-alloys from the high temperature airflow damage. High melting point, ultra-low thermal conductivity, large thermal expansion coefficient, excellent damage tolerance and moderate mechanical properties are the main requirements of promising TBC materials. In order to improve the efficiency of jet and/or gas turbine engines, which is the key of improved thrust-to-weight ratios and the energysaving, significant efforts have been made on searching for enhanced TBC materials. Theoretically, density functional theory has been successfully used in scanning the structure and properties of materials, and at the same time predicting the mechanical and thermal properties of promising TBC materials for high and ultrahigh temperature applications, which are validated by subsequent experiments. Experimentally,doping and/or alloying are also widely applied to further decrease their thermal conductivities. Now, the strategy through combining theoretical calculations and experiments on searching for next generation thermal insulator materials is widely adopted. In this review, the common used techniques and the recent advantages on searching for promising TBC materials in both theory and experiments are summarized. 展开更多
关键词 THERMAL BARRIER coatings Oxide First principles calculation THERMAL PROPERTIES Mechanical PROPERTIES
Conductive property of Zr0.1Fe0.9V1.1Mo0.9O7 with low thermal expansion
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作者 何小可 戚恒 +3 位作者 徐启 刘献省 许磊 袁保合 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期244-248,共5页
Low thermal expansion materials are mostly ceramics with low conductive property,which limits their applications in electronic devices.The poor conductive property of ceramic ZrV2O7 could be improved by bi-substitutio... Low thermal expansion materials are mostly ceramics with low conductive property,which limits their applications in electronic devices.The poor conductive property of ceramic ZrV2O7 could be improved by bi-substitution of Fe and Mo for Zr and V,accompanied with low thermal expansion.Zr0.1Fe0.9V1.1Mo0.9O7 has electrical conductivity of 8.2×10^-5 S/cm and 9.41×10^4 S/cm at 291 K and 623 K,respectively.From 291 K to 413 K,thermal excitation leads to the increase of carrier concentration,which causes the rapid decrease of resistance.At 413–533 K,the conductivity is unchanged due to high scattering probability and a slowing increase of carrier concentration.The conductivity rapidly increases again from 533 K to 623 K due to the intrinsic thermal excitation.The thermal expansion coefficient of Zr0.1Fe0.9V1.1Mo0.9O7 is as low as 0.72×10^6 K^-1 at 140–700 K from the dilatometer measurement.These properties suggest that Zr0.1Fe0.9V1.1Mo0.9O7 has attractive application in electronic components. 展开更多
关键词 low THERMAL EXPANSION CONDUCTIVITY THERMAL EXCITATION electric IMPEDANCE
Thermal state calculation of chamber in small thrust liquid rocket engine for steady state pulsed mode
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作者 Alexey Gennadievich VOROBYEV Svatlana Sergeevna VOROBYEVA +1 位作者 Lihui ZHANG Evgeniy Nikolaevich BELIAEV 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第2期253-262,共10页
This paper presents a method of thermal state calculation of combustion chamber in small thrust liquid rocket engine. The goal is to predict the thermal state of chamber wall by using basic parameters of engine: thrus... This paper presents a method of thermal state calculation of combustion chamber in small thrust liquid rocket engine. The goal is to predict the thermal state of chamber wall by using basic parameters of engine: thrust level, propellants, chamber pressure, injection pattern, film cooling parameters, material of wall and their coating, etc. The difficulties in modeling the startup and shutdown processes of thrusters lie in the fact that there are the conjugated physical processes occurring at various parameters for non-design conditions. A mathematical model to predict the thermal state of the combustion chamber for different engine operation modes is developed. To simulate the startup and shutdown processes, a quasi-steady approach is applied by replacing the transient process with time-variant operating parameters of steady-state processes. The mathematical model is based on several principles and data commonly used for heat transfer modeling: geometry of flow part, gas dynamics of flow, thermodynamics of propellants and combustion spices, convective and radiation heat flows, conjugated heat transfer between hot gas and wall, and transient approach for calculation of thermal state of construction. Calculations of the thermal state of the combustion chamber in single-turn-on mode show good convergence with the experimental results. The results of pulsed modes indicate a large temperature gradient on the internal wall surface of the chamber between pulses and the thermal state of the wall strongly depends on the pulse duration and the interval. 展开更多
关键词 Combustion CHAMBER Film cooling Mathematical model NONSTATIONARY THERMAL MODE SMALL THRUST liquid rocket engine Steady pulse MODE THERMAL state
Performance of a Thermal Bipedal Walker on Inclined Surfaces with Different Leg CoMs
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作者 Lingchao Su Takeru Nemoto Akio Yamamoto 《仿生工程学报:英文版》 SCIE EI CSCD 2019年第3期540-549,共10页
This paper investigates the walking performance of a thermal walker on various inclined surfaces. The thermal walker can walk only by ground heat energy using bimetal sheets. The walking performance on slopes is analy... This paper investigates the walking performance of a thermal walker on various inclined surfaces. The thermal walker can walk only by ground heat energy using bimetal sheets. The walking performance on slopes is analyzed using a simplified walker model. The analytical result is compared with the two sets of walking experiments, on slopes with either pitch or roll inclinations. The analyses and the experiments are done with different Center-of-Mass (CoM) positions of the legs, which considerably influence the walking performance. It was found that, on up/down slopes, the stride of the thermal walker changes almost linearly with the slope angle. When the CoM was close to the center of the walker body, the walker walked backward on upward slopes. With CoM largely shifted backward, the walker could walk up slopes but did not walk down slopes well. On the other hand, when walking along a contour line of a slope, the stride decreased as the slope angle increased. The smaller leg swing distances would be caused by the change of leg swing time on such slopes. 展开更多
关键词 bipedal WALKER BIMETAL THERMAL WALKER THERMAL ACTUATOR slope
Modification of NiCoCrAlY with Pt: Part Ⅱ. Application in TBC with pure metastable tetragonal(t’) phase YSZ and thermal cycling behavior
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作者 Chuntang Yu He Liu +3 位作者 Chengyang Jiang Zebin Bao Shenglong Zhu Fuhui Wang 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第3期350-359,共10页
A thermal barrier coating system comprising Pt-modified NiCoCrAlY bond coating and nanostructured 4mol.% yttria stabilized zirconia(4YSZ, hereafter) top coat was fabricated on a second generation Ni-base superalloy. T... A thermal barrier coating system comprising Pt-modified NiCoCrAlY bond coating and nanostructured 4mol.% yttria stabilized zirconia(4YSZ, hereafter) top coat was fabricated on a second generation Ni-base superalloy. Thermal cycling behavior of NiCoCrAlY-4 YSZ thermal barrier coatings(TBCs) with and without Pt modification was evaluated in ambient air at 1100?C up to 1000 cycles, aiming to investigate the effect of Pt on formation of thermally grown oxide(TGO) and oxidation resistance. Results indicated that a dual layered TGO, which consisted of top(Ni,Co)(Cr,Al)2O4 spinel and underlying α-Al2O3, was formed at the NiCoCrAlY/4 YSZ interface with thickness of 8.4μm, accompanying with visible cracks at the interface. In contrast, a single-layer and adherent α-Al2O3 scale with thickness of 5.6μm was formed at the interface of Pt-modified NiCoCrAlY and 4 YSZ top coating. The modification of Pt on NiCoCrAlY favored the exclusive formation of α-Al2O3 and the reduction of TGO growth rate, and thus could effectively improve overall oxidation performance and extend service life of TBCs. Oxidation and degradation mechanisms of the TBCs with/without Pt-modification were discussed. 展开更多
关键词 Pt-modification NICOCRALY THERMAL barrier coating(TBC) THERMAL cycling Thermally grown oxide(TGO)
Influence of Microstructures on Thermal Shock and Sintering Behavior of YSZ-based Thermal Barrier Coatings 预览
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作者 Kirsten Bobzin Lidong Zhao +1 位作者 Mehmet Ote Tim Konigstein 《表面技术》 EI CAS CSCD 北大核心 2019年第4期28-33,共6页
In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal b... In this study, two thermal barrier coatings based on YSZ were produced by using a commercially available agglomerated and sintered powder and a special spray powder prepared by high energy ball milling. Both thermal barrier coatings exhibited similar overall porosities, but significantly different microstructures. Application of the special spray powder prepared by high energy ball milling led to a microstructure with numerous inclusions of semi-molten agglomerates, which introduced a plethora of clusters of fine pores into the coating and several more microstructural defects. This microstructure resulted in a significantly better thermal shock behavior compared to the conventional thermal barrier coating. The heat treatment of both thermal barrier coatings atθ=1150℃for t=100 h led to a sintering of both coatings. The results were reduced overall porosity and significantly increased fracture toughness. A correlation between the fracture toughness of both coatings after the heat treatment and the thermal shock life time could not be identified. 展开更多
关键词 THERMAL barrier coating ZrO2-7%Y2O3 high energy ball MILLING THERMAL shock
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Synthesis and Thermal Properties of Three Energetic Ion Salts of 3,6-Bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]- 1,2,4,5-tetr azine
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作者 ZHOU Jie WU Shaojie +6 位作者 ZHANG Wenhui LIU Qmg YANG Bin REN Yinghui MA Haixia ZHAO Fengqi HU Rongzu 《高等学校化学研究:英文版》 SCIE CAS CSCD 2019年第3期403-409,共7页
Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesi... Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesized and characterized by elemental analysis, Fourier transform infrared spectrometry, NMR spectroscopy, and ^13C NMR spectroscopy. The crystal structure of compound 1 was determined by single-crystal X-ray crystallography, and structural analysis revealed that it belonged to the monoclinic system with P21/c space group. In addition, the thermal behavior of the three compounds was studied by differential scanning calorimetry and thermogravimetry techniques. The thermal decomposition peak temperatures of the compounds were 574.89, 545.60, and 606.72 K, indicating that the three ion salts exhibited good thermal stability. Tlie kinetic mechanism equations of the main decomposition process and the entropy of activation(△S^≠), enthalpy of activation(△H^≠), and Gibbs free energy of activation(△G^≠) of the three compounds were also obtained. Moreover, the thermal safety of the compounds was evaluated by the values of the self^accelerated decomposition temperature(Tsadt)5 thermal ignition temperature(TTIT), and critical temperature of thermal explosion(7b). The results showed that all the compounds demonstrated good thermal safety, and the thermal safety of compound 3 was better than that of the others. 展开更多
关键词 3 6-Bis[( 1H-1 2 3 4-tetrazol-5-yl)-ammo]-l 2 4 5-tetrazine Ionic salt THERMAL behavior THERMAL safety
发动机热管理技术研究 预览
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作者 张强 韩令海 +1 位作者 王占峰 史鹏礼 《汽车文摘》 2019年第6期58-62,共5页
发动机热管理技术是通过冷却策略的控制改善发动机冷起动暖机速度,从而降低发动机冷起动工况油耗和排放的关键技术。本文深入挖掘了国际上文献资料,整理了电子节温器技术、电动水泵技术、分体冷却技术、智能热管理技术,并针对不同技术... 发动机热管理技术是通过冷却策略的控制改善发动机冷起动暖机速度,从而降低发动机冷起动工况油耗和排放的关键技术。本文深入挖掘了国际上文献资料,整理了电子节温器技术、电动水泵技术、分体冷却技术、智能热管理技术,并针对不同技术对发动机冷起动暖机速度的改善情况,对国际上发动机热管理技术进展进行了归纳、总结和分析。 展开更多
关键词 发动机 热管理 电子节温器 电动水泵 智能热管理
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Dynamical evolution of photon-added thermal state in thermal reservoir
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作者 徐学翔 袁洪春 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第11期99-104,共6页
The dynamical behavior of a photon-added thermal state(PATS) in a thermal reservoir is investigated by virtue of Wigner function(WF) and Wigner logarithmic negativity(WLN), where this propagation model is abstracted a... The dynamical behavior of a photon-added thermal state(PATS) in a thermal reservoir is investigated by virtue of Wigner function(WF) and Wigner logarithmic negativity(WLN), where this propagation model is abstracted as an input–output problem in a thermal-loss channel. The density operator of the output optical field at arbitrary time can be expressed in the integration form of the characteristics function of the input optical field. The exact analytical expression of WF is given, which is closely related to the Laguerre polynomial and is dependent on the evolution time and other interaction parameters(related with the initial field and the reservoir). Based on the WLN, we observe the dynamical evolution of the PATS in the thermal reservoir. It is shown that the thermal noise will make the PATS lose the non-Gaussianity. 展开更多
关键词 quantum statistics master equation photon-added thermal state thermal reservoir Wigner logarithmic negativity
Thermal conductivity of complex materials
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作者 G.Jeffrey Snyder Matthias T.Agne Ramya Gurunathan 《国家科学评论:英文版》 CSCD 2019年第3期380-381,共2页
In the discussion and analysis of thermal properties(e.g.heat capacity,thermal conductivity)the Debye approximation is typically used to describe the collective behavior of lattice vibrations(phonons)in solid material... In the discussion and analysis of thermal properties(e.g.heat capacity,thermal conductivity)the Debye approximation is typically used to describe the collective behavior of lattice vibrations(phonons)in solid materials.Because the Debye model has been successful in explaining many properties of materials,particularly in contrast to the non-dispersive model considered by Einstein,the Debye model is often the starting point of introductory textbooks in solid state physics.Yet the more we learn about the full spectrum of lattice vibrations. 展开更多
关键词 THERMAL CONDUCTIVITY COLLECTIVE BEHAVIOR THERMAL PROPERTY
An integrated approach to assess the ecological and chemical status of lakes with HOD/AHOD:a case study of two lakes 预览
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作者 Serdar GONCU Erdem ALBEK 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第1期146-159,共14页
The thermal stratification of the lakes impedes the transfer of atmospheric oxygen into the lower layers of the lake.In lakes which are affected by diverse anthropogenic infl uences,the increasing organic matter amoun... The thermal stratification of the lakes impedes the transfer of atmospheric oxygen into the lower layers of the lake.In lakes which are affected by diverse anthropogenic infl uences,the increasing organic matter amounts lead to a sharp decrease in hypolimnetic oxygen amounts,aided by thermal stratification,and anaerobic conditions arise.The determination of hypolimnetic oxygen demand(HOD)and areal hypolimnetic oxygen demand(AHOD)and their monitoring represent an integrated approach to investigate the oxygenation of lakes,the nutrient conditions,and the physicochemical dynamics.In this study,two lakes differing by size and affected by different anthropogenic sources,are investigated in this respect.At first,bathymetric studies were conducted to determine the depth,surface area,and volume relationships.Then,based on monitoring studies conducted in 2013 and 2014,the thermal stratification dynamics and layer properties were established using the relative thermal resistance to mixing(RTRM)index based on temperature and density profiles.Following this,the oxygen depletion rates were determined by oxygen and temperature profiling in the hypolimnion.For the years of 2013 and 2014,the AHOD values for the Borabey Pond which is far from anthropogenic infl uences,were found to be 0.848 and 0.569 g O 2/(m·d),respectively.The AHOD values for the Porsuk Reservoir which was overburdened for years by industrial and domestic pollution were found to be 4.263 and 5.099 g O 2/(m·d),larger than its counterpart by almost sevenfold.The HOD and AHOD monitoring can be considered to a valuable tool for assessing the ecological and chemical status of lakes within Annex 5 of the Water Framework Directive and as an integrated approach to assess and monitor the status of lakes. 展开更多
关键词 hypolimnetic OXYGEN demand(HOD) areal hypolimnetic OXYGEN demand(AHOD) THERMAL stratification relative THERMAL resistance to mixing(RTRM) Borabey POND Porsuk Dam
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Effect of particle size on the thermal performance of NaNO3/SiC)2/C composite phase-change materials
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作者 Liang Liu Liqiong Wang +2 位作者 Weichun Ge Yanfeng Ge Yun Huang 《颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第3期169-175,共7页
Storage of thermal energy is a key technology for energy conservation and application of renewable energy sources. In this paper, the thermal performance of inorganic composite phase-change materials (PCMs;NaNO3/SiO2/... Storage of thermal energy is a key technology for energy conservation and application of renewable energy sources. In this paper, the thermal performance of inorganic composite phase-change materials (PCMs;NaNO3/SiO2/C) is studied under extreme thermal conditions and the effect of raw particle size is examined. We designed a thermal shock test platform with a diffusive combustion system and in-situ infrared thermal imaging. The influences of the heat flux magnitude and exposure time on the performance of the PCMs were examined under vertical thermal shock conditions. Leakage of molten salt in the composite PCMs was observed as the heat flux reached a threshold point. The morphology and thermal properties were characterized by ex-situ SEM, XRD, DSC, and BET. Raw particles with sizes in the range of 105-500 μm were used to synthesize the composite material and examine its role in thermal shock behavior. Our experiments showed that deterioration of the thermal storage density was slowed as the particle size was increased. This work provides useful guidance for improving the anti-thermal shock ability of future material designs. 展开更多
关键词 THERMAL STORAGE Phase CHANGE material PARTICLE SIZE THERMAL shock DECOMPOSITION temperature
Multiphysics Analysis for Thermal Management of a 3 MeV, 325 MHz Radio Frequency Quadrupole Accelerator for Indian Spallation Neutron Source 预览
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作者 N. K. Sharma C. P. Paul +2 位作者 S. C. Joshi G. V. Kane A. Chaturvedi 《电磁分析与应用期刊(英文)》 2019年第5期55-78,共24页
We present multiphysics design studies for thermal management of a 325 MHz 3 MeV Radio Frequency Quadrupole (RFQ) structure for the front end of 1 GeV proton linac for proposed Indian Spallation Neutron Source (ISNS).... We present multiphysics design studies for thermal management of a 325 MHz 3 MeV Radio Frequency Quadrupole (RFQ) structure for the front end of 1 GeV proton linac for proposed Indian Spallation Neutron Source (ISNS). Physics design of RFQ for ISNS application has been carried out for 10% (maximum) duty factor. During high power operation of RFQ, RF-induced heating would result in temperature rise, thermal deformations and frequency shift of RFQ from designed values. Therefore thermal management is one of the important design considerations for RFQ development. During design studies, electromagnetic analysis of RFQ cavity is performed to compute RF induced heat fluxes on RFQ surfaces using SUPERFISH and ANSYS software. Simulated results for both codes were compared and found in well agreement. A water cooling scheme has been designed to absorb RF induced heat from RFQ structure. Cooling parameters are optimized by employing univariate search method optimization technique. An RF-Thermal-Structural-RF coupled multi-physics analysis methodology is developed to evaluate thermal induced frequency detuning of ISNS RFQ structure. Parametric studies are carried out to investigate the effect of cooling water temperatures on RFQ frequency. Based on analysis results, cooling water temperatures are varied to restore RFQ frequency to designed values. Thus, water cooling will not only remove heat from structure, but it will also be used for online control of resonating frequency during steady state operation of RFQ structure. Results of numerical studies carried out for thermal management of ISNS RFQ are presented in this paper. 展开更多
关键词 MULTIPHYSICS RFQ ISNS ANSYS Electromagnetic Thermal Structural Water Cooling DETUNING
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Thermal Performance and Mechanics Characteristic for Double Layer Microchannel Heat Sink
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作者 XU Yupeng GONG Liang +2 位作者 LI Yongtong BAI Zhang XU Minghai 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第2期271-282,共12页
Double layer micro-channel heat sink(DLMCHS) has been widely used in various electronic devices;however, the existence of the nonuniform thermal strain distribution in actual operation has adverse effect on the overal... Double layer micro-channel heat sink(DLMCHS) has been widely used in various electronic devices;however, the existence of the nonuniform thermal strain distribution in actual operation has adverse effect on the overall stability. In this paper, two optimized designs of DLMCHS with cutting baffles on top and bottom layers are presented based on the traditional DLMCHS. The heat transfer and thermal stress performance are numerically analyzed and compared with the traditional DLMCHS. The results indicate that cutting baffles of micro-channels remarkably improves heat transfer and thermal stress performance. The optimized design with cutting baffles on the bottom layer decreases thermal strain but deteriorates heat transfer performance. The model with cutting baffles on the top layer has better combined thermal strain and heat transfer performance, which reduces thermal strain by about 1.5 times and enhances heat transfer by about 26.5%. For the design with cutting baffles on the top board, adding metal foam in the inlet collector can decrease the total minimum thermal strain by 51.4% and maximum temperature by 1.4 K, and increase the Nusselt number by 15%. These results indicate that DLMCHS with cutting baffles on the top layer has great potential for thermal managements on electronic devices with high power density. 展开更多
关键词 DOUBLE LAYER MICRO-CHANNEL heat SINK THERMAL STRAIN THERMAL performance optimized design
Thermal and saline tolerance of Antarctic krill Euphausia superba under controlled in-situ aquarium conditions 预览
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作者 ZHU Guoping LIU Zijun +3 位作者 YANG Yang WANG Zhen YANG Wenjie XU Liuxiong 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第3期1080-1089,共10页
As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations ne... As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations needed for observation have inhibited in-situ experiments in the field.Hence,the thermal and saline tolerance of krill were examined under in-situ aquarium conditions with different controlled scenarios.According to the experiments,the critical lethal times of krill were 24h,2h and 0.5h under 9℃,12℃,and 15℃,respectively,and the estimated 50%lethal times were about 17.1 h and 1.7 h under 12℃and 15℃,respectively.Additionally,the critical lethal times(the estimated 50%lethal times)of krill were approximately 14h and 0.5h(about 22.9 h and 1.7 h)of salinity under 19.7 and 15.9,respectively.The observed critical and 50%lethal times of krill were 0.5 h and approximately 1.4 h,respectively,salinity under 55.2.The critical and 50%lethal temperatures of krill were 13℃and approximately 14.2℃,respectively.Additionally,the critical and 50%lethal salinity was 19.6 and approximately 17.5 for the lower saline(below normal oceanic salinity[34.4])environment and 50.3 and approximately 53.2 for the higher saline(above 34.4)environment,respectively.The upper thermal and saline preferences of krill can be considered 6℃and 26.8 to 41.2,respectively.These results can provide potential scenarios for predicting the possible fate of this key species in the Southern Ocean. 展开更多
关键词 Euphausia superba THERMAL TOLERANCE SALINE TOLERANCE THERMAL PREFERENCE IN-SITU AQUARIUM experiment
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Investigation on the key aspects of l-arginine para nitrobenzoate monohydrate single crystal:A non-linear optical material
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作者 Sonia N.Vijayan +5 位作者 Mahak Vij Kanika Thu krai Naghma Khan D.Haranath Rajnikant M.S.Jayalakshmy 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期701-708,共8页
In the contemporary days,non-linear optical materials(NLO)are getting higher attention as per the increasing demand in optical communication and data storage technology.Consequently,they explore various physical prope... In the contemporary days,non-linear optical materials(NLO)are getting higher attention as per the increasing demand in optical communication and data storage technology.Consequently,they explore various physical properties of the NLO material for their industrial applications.In current report,l-arginine p-nitrobenzoate monohydrate(LANB)single crystals were obtained by adopting slow cooling technique.The structural confirmation of grown single crystal was carried out using single crystal X-Ray diffractometer.Presence of strain within single crystal was deduced using Hall–Williamson relation.Various defects associated within single crystal were assessed using high resolution XRD.Additionally,its crystalline quality was again confirmed by time resolved photoluminescence spectroscopy(TRPL).Using transmission spectra,the cut off wavelength and band gap of the host material was determined to be nearly 420 nm and 2.9 e V respectively.The dielectric property has been recorded by varying the frequency ranging from 50 Hz to 100 k Hz.The curve suggests that dielectric loss value is less at high frequency ensures the suitability of crystal in photonics and NLO based devices.The laser damage threshold values were also measured for single and multiple shots.Thermal parameters of the titled compound were calculated using PPE.In photoconductivity measurement,negative photoconductivity has been observed in titled compound.Microhardness studies were also performed on single crystal to explore its mechanical properties. 展开更多
关键词 PHOTOLUMINESCENCE THERMAL conductivity Specific heat THERMAL effusivity Damage threshold
Modeling of thermal conductivity and density of alumina/silica in water hybrid nanocolloid by the application of Artificial Neural Networks
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作者 Sathishkumar Kannaiyan Chitra Boobalan +1 位作者 Fedal Castro Nagarajan Srinivas Sivaraman 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第3期726-736,共11页
In this research work,the thermal conductivity and density of alumina/silica(Al2O3/SiO2)in water hybrid nanofluids at different temperatures and volume concentrations have been modeled using the artificial neural netw... In this research work,the thermal conductivity and density of alumina/silica(Al2O3/SiO2)in water hybrid nanofluids at different temperatures and volume concentrations have been modeled using the artificial neural networks(ANN).The nanocolloid involved in the study was synthesized by the two-step method and characterized by XRD,TEM,SEM–EDX and zeta potential analysis.The properties of the synthesized nanofluid were measured at various volume concentrations(0.05%,0.1%and 0.2%)and temperatures(20 to 60°C).Established on the observational data and ANN,the optimum neural structure was suggested for predicting the thermal conductivity and density of the hybrid nanofluid as a function of temperature and solid volume concentrations.The results indicate that a neural network with 2 hidden layers and 10 neurons have the lowest error and a highest fitting coefficient of thermal conductivity,whereas in the case of density,the structure with 1 hidden layer consisting of 4 neurons proved to be the optimal structure. 展开更多
关键词 THERMAL conductivity Modeling HYBRID NANOCOLLOIDS ANN THERMAL energy
Thermal–structure coupling analysis and multi-objective optimization of motor rotor in MSPMSM
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作者 Luxin ZHAI Jinji SUN +2 位作者 Xin MA Weitao HAN Xiaosan LUO 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第7期1733-1747,共15页
With the high speed, the rotor of magnetically suspended permanent magnet synchronous motor(MSPMSM) suffers great thermal stress and mechanical stress resulting from the temperature rise problem caused by rotor losses... With the high speed, the rotor of magnetically suspended permanent magnet synchronous motor(MSPMSM) suffers great thermal stress and mechanical stress resulting from the temperature rise problem caused by rotor losses, which leads to instability and inefficiency.In this paper, the mechanical–temperature field coupling analysis is conducted to analyze the relationship between the temperature field and structure, and multi-objective optimization of a rotor is performed to improve the design reliability and efficiency. Firstly, the temperature field is calculated by the 2 D finite element model of MSPMSM and the method of applying the 2 D temperature result to the 3 D finite element model of the motor rotor equivalently is proposed. Then the thermal–structure coupling analysis is processed through mathematic method and finite element method(FEM),in which the 3 D finite element model is established precisely in a way and approaches the practical operation state further. Moreover, the impact produced by the temperature and structure on the mechanical strength is analyzed in detail. Finally, the optimization mathematical model of the motor rotor is established with Sequential Quadratic Programming-NLPQL selected in the optimization scheme. Through optimization, the strength of the components in the motor rotor increases obviously and satisfies the design requirement, which to a great extend enhances the service life of the MSPMSM rotor. 展开更多
关键词 FEM MSPMSM MULTI-OBJECTIVE OPTIMIZATION THERMAL STRESS Thermal–structure COUPLING analysis
Effect of building interface form on thermal Check foi comfort in gymnasiums in hot and humid climates
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作者 Xiaodan Huang Xiaoli Ma Qingyuan Zhang 《建筑学研究前沿(英文版)》 CSCD 2019年第1期32-43,共12页
The thermal environment and thermal comfort of a building are greatly affected by the desig n of the build ing interface form. Most con temporary architectural designs con sider only the relations between architectura... The thermal environment and thermal comfort of a building are greatly affected by the desig n of the build ing interface form. Most con temporary architectural designs con sider only the relations between architectural form and architectural beauty. Few studies on the correlati on of architectural form and thermal comfort address the in flue nee of architectural form on thermal comfort and thermal environment. These studies are particularly important for gymnasium architectures located in hot and humid areas, which have high requirements for thermal comfort. This paper presents an experimental investigati on and an an alysis of the effect of the building in terface form of gymnasiums on thermal comfort in hot and humid subtropical regions during summer. Results showed that the influence of the top interface forms on thermal comfort is mainly dominated by the mea n radiant temperature, which could be con trolled to improve thermal comfort. The in fluence of side interface forms on thermal comfort is mainly domi nated by air velocity, and thermal comfort could be improved by promoting natural ventilation on the side interface form design to reduce indoor heat. This research enhanced our understanding of the relation between the in terface form and the thermal comfort of gymnasiums. In addition, this paper provides a theoretical reference for the sustainable design of gymnasiums in hot and humid climates. 展开更多
关键词 THERMAL COMFORT THERMAL environment Interface FORM Standard effective temperature GYMNASIUM HOT and humid climate
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