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玉米热导系“M丹”选系的选育和应用 被引量:3
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作者 杨克昌 高祥扩 赵自仙 《西南农业学报》 CSCD 北大核心 2000年第2期32-38,共7页
“M丹”选系是用我国骨干自交系之一的“丹340”与含墨西哥引入的热带Tuxpeno种质和云南西南部地方种质的自交系“MH12”杂交后自交分离选育而成的,它继承了“丹340”的配合力高,对大小斑病抗性强的优点,也纳入了... “M丹”选系是用我国骨干自交系之一的“丹340”与含墨西哥引入的热带Tuxpeno种质和云南西南部地方种质的自交系“MH12”杂交后自交分离选育而成的,它继承了“丹340”的配合力高,对大小斑病抗性强的优点,也纳入了低纬热带种质抗逆性强、抗穗粒腐病的特点。“M丹”参与组配的杂交组合在涉及产量的穗粗、穗行数、穗粒数和千粒重4个主要性状上具有明显的优势。用“M丹”选系参与组配的“通单202”、“通黄 3号”和“通玉 2号”在云南省区域试验和多点试种中产量均名列前茅,在生产示范中增产显著,抗多种病害,适应云南省立体气候的多种生态类型。新配优势组合“云试6号”、“云试8号”、“云试9号”、“通黄4号”和“通黄5号”等具有较高的产量潜力。“M丹”选系与美国玉米带种质选系、低纬热带、亚热带优势群ETO、Suwan种质选系和我国贵州、云南等地的地方种质选系组配均有较高的配合力。 展开更多
关键词 玉米 热导系 “M丹”选 选育
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玉米热导二环系“87”组配强优势组合的研究 被引量:7
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作者 刘宗华 陈伟程 +5 位作者 罗福和 季良越 汤继华 胡彦民 黄西林 季洪强 《玉米科学》 CAS CSCD 1998年第2期6-9,共4页
以热导二环系“87”作为亲本之一 ,与不同类群测验系杂交 ,所配组合均表现出较强的杂种优势 ,尤其豫单 870 3即综 3× 87- 1优势最强。 1993~ 1996年 ,在省内外区试、生产示范和多点试验中 ,豫单 870 3的产量连年排名第一。该组合... 以热导二环系“87”作为亲本之一 ,与不同类群测验系杂交 ,所配组合均表现出较强的杂种优势 ,尤其豫单 870 3即综 3× 87- 1优势最强。 1993~ 1996年 ,在省内外区试、生产示范和多点试验中 ,豫单 870 3的产量连年排名第一。该组合表现高产、优质、抗病、持绿期长 ,是目前替换丹玉 13的理想品种。研究结果表明 ,利用热导二环系组配强优势组合是利用热带资源快出品种的有效途径。 展开更多
关键词 玉米 二环 杂种优势 选育 产量表现
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Microstructure and thermophysical properties of SiC/Al composites mixed with diamond 被引量:6
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作者 郭宏 韩媛媛 +2 位作者 张习敏 贾成厂 徐骏 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第1期170-174,共5页
The thermophysical properties of the SiC /Al composites mixed with diamond(SiC-Dia/Al) were studied through theoretical calculation and experiments. The thermal conductivity and the thermal expansion coefficient of ... The thermophysical properties of the SiC /Al composites mixed with diamond(SiC-Dia/Al) were studied through theoretical calculation and experiments. The thermal conductivity and the thermal expansion coefficient of the SiC-Dia/Al were calculated by differential effective medium(DEM) theoretical model and extended Turner model, respectively. The microstructure of the SiC-Dia/Al shows that the combination between SiC particles and Al is close, while that between diamond particles and Al is not close. The experimental results of the thermophysical properties of the SiC-Dia/Al are consistent with the calculated ones. The calculation results show that when the volume ratio of the diamond particles to the SiC particles is 3:7, the thermal conductivity and the thermal expansion coefficient can be improved by 39% and 30% compared to SiC/Al composites, respectively. In other words, by adding a small amount of diamond particles, the thermophysical properties of the composites can be improved effectively, while the cost increases little. 展开更多
关键词 SiC/Al composites mixed with diamond thermal conductivity thermal expansion coefficient MICROSTRUCTURE
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Microstructure and properties of electronic packaging box with high silicon aluminum-base alloy by semi-solid thixoforming 被引量:10
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作者 贾琪瑾 刘俊友 +1 位作者 李艳霞 王文韶 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期80-85,共6页
The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the b... The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the box were observed by optical microscopy and scanning electron microscopy,and the thermophysical and mechanical properties of the box were tested.The results show that there exists the segregation phenomenon between the primary Si phase and the liquid phase during thixoforming,the liquid phase flows from the box,and the primary Si phase accumulates at the bottom of the box.The volume fraction of primary Si phase decreases gradually from the bottom to the walls.Accordingly,the thermal conductivities of bottom center and walls are 107.6 and 131.5 W/(m·K),the coefficients of thermal expansion(CTE) are 7.9×10-6 and 10.6×10-6 K-1,respectively.The flexural strength increases slightly from 167 to 180 MPa.The microstructures and properties of the box show gradient distribution overall. 展开更多
关键词 high silicon aluminum-base alloy electronic packaging semi-solid thixoforming thermal conductivity coefficient of thermal expansion
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Microstructures and properties of Al-45%Si alloy prepared by liquid-solid separation process and spray deposition 被引量:5
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作者 李艳霞 刘俊友 +1 位作者 王文韶 刘国权 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期970-976,共7页
The microstructures and properties of A1-45%Si alloy prepared by liquid-solid separation (LSS) process and spray deposition (SD) were studied. The results show that the size, shape and distribution of the primary ... The microstructures and properties of A1-45%Si alloy prepared by liquid-solid separation (LSS) process and spray deposition (SD) were studied. The results show that the size, shape and distribution of the primary Si phase have different influence on the properties of alloys. Comparing with the Si particles with irregular shape, fine size and continuous distribution in SD alloy, the primary Si phase in LSS alloy is sphere-like, coarse and surrounded by the continuous AI matrix. The microstructure features of LSS alloy are beneficial to the higher thermal conductivity and lower thermal expansion coefficient at room temperature. The fine Si particle in SD alloy is advantageous to improving the mechanical properties. The increasing rates of thermal expansion coefficient with temperature are influenced by the distribution of the Si particles, where a lower rate is obtained in SD alloy with continuous Si particles. The agreement of thermal expansion coefficient with the model in LSS alloy differs from that in the SD alloy because of the different microstructure characteristics. 展开更多
关键词 aluminum-silicon alloy Si particle liquid-solid separation spray deposition thermal conductivity thermal expansioncoefficient
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NUMERICAL SIMULATIONS OF TEMPERATURE FIELD IN DIRECT METAL LASER SINTERING PROCESS 被引量:6
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作者 顾冬冬 沈以赴 +2 位作者 刘满仓 潘琰峰 胥橙庭 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2004年第3期225-233,共9页
A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radia... A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.[KH3/4D] 展开更多
关键词 direct metal laser sintering (DMLS) mathematical model temperature field numerical simulation
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Microstructure and properties of SiC_p/Al electronic packaging shell produced by liquid-solid separation 被引量:3
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作者 郭明海 刘俊友 李艳霞 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1039-1045,共7页
The electronic packaging shell of high silicon carbide (54%SiC, volume fraction) aluminum-based composites was produced by liquid-solid separation technique. The characteristics of distribution and morphology of SiC... The electronic packaging shell of high silicon carbide (54%SiC, volume fraction) aluminum-based composites was produced by liquid-solid separation technique. The characteristics of distribution and morphology of SiC as well as the shell’s fracture surface were examined by optical microscopy and scanning electron microscopy, and the thermo-physical and mechanical properties of the shell were also tested. The results show that Al matrix has a net-like structure while SiC is uniformly distributed in the Al matrix. The SiCp/Al composites have a low density of 2.93 g/cm^3, and its relative density is 98.7%. Thermal conductivity of the composites is 175 W/(·K), coefficient of thermal expansion (CTE) is 10.3×10^-6 K-1 (25-400 ℃), compressive strength is 496 MPa, bending strength is 404.5 MPa, and the main fracture mode is brittle fracture of SiC particles accompanied by ductile fracture of Al matrix.Its thermal conductivity is higher than that of Si/Al alloy, and its CTE matches with that of the chip material. 展开更多
关键词 liquid-solid separation near-net thixoforming SiCp/Al electronic packaging shell thermal conductivity coefficient ofthermal expansion
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Theoretical expressions of thermal conductivity of wood 被引量:8
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作者 杨庆贤 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第1期43-46,共5页
In this paper, the theoretical expressions of wood thermal conductiv ity in the choral and radical direction are derived from the micro-structure of wood by applying some basic principles in physical mechanics. The t... In this paper, the theoretical expressions of wood thermal conductiv ity in the choral and radical direction are derived from the micro-structure of wood by applying some basic principles in physical mechanics. The thermal conduc tivities of about twenty species of trees were calculated by means of the expres sions and compared with its experimental values under the same condition. The av erage relative error is about 5%, so the calculation result is satisfactory. 展开更多
关键词 Thermal conductivity WOOD Choral direction Radical direction Theor etical expression
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STUDY ON THE HEAT AND MASS TRANSPORT PROPERTIES OF BEEF UNDERGOING FREEZE DRYING
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作者 齐锡龄 金志军 +1 位作者 李惟毅 郑宗和 《Transactions of Tianjin University》 EI CAS 2000年第1期14-17,共4页
This paper establishes the mathematical model in calculating the effective thermal conductivity and the effective mass diffusivity of dried layer of beef undergoing freeze drying process.First,experimental measurement... This paper establishes the mathematical model in calculating the effective thermal conductivity and the effective mass diffusivity of dried layer of beef undergoing freeze drying process.First,experimental measurements are done on the dehydrated quantity as well as temperature variations at different locations of the beef steak.Then the effective thermal conductivity and the effective mass diffusivity are calculated by applying the above mathematical model on the data of the dehydrated quantity.These two coefficients are further used in the calculation of temperature distribution.The result is in agreement with the measurement,thus confirming the correctness of the model and the values of the coefficients. 展开更多
关键词 sublimation drying thermal conductivity mass diffusivity
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Effects of TiO2 nanoparticles on thermal conductivity of heat transfer oil 被引量:8
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作者 YIN Xiang KOU Guang-xiao +2 位作者 XU Ai-xiang FU Tao ZHU Jie 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第8期2129-2135,共7页
There is a lack of thermophysical data of heat transfer oil and nano-oil in the high temperature range of 50-300 ℃ for designing and developing heat transfer oil furnace and its heating systems. In the present study,... There is a lack of thermophysical data of heat transfer oil and nano-oil in the high temperature range of 50-300 ℃ for designing and developing heat transfer oil furnace and its heating systems. In the present study, the thermal conductivity values of heat transfer oil and TiO2 nano-oil in the above high temperature range were measured by a newly developed high-temperature thermal conductivity meter. Based on the principle of least square method, the thermal conductivity values obtained from experiments were fitted separately, and the correlation between thermal conductivity and temperature of heat transfer oil and TiO2 nano-oil was obtained. The results show that the thermal conductivity and the increased percentage of thermal conductivity of TiO2 nano-oil are proportional to the increase of particle size and mass fraction of nanoparticles, but thermal conductivity is in reverse proportion to the increase of temperature and the increased percentage of thermal conductivity is less affected by temperature. 展开更多
关键词 TiO2 nano-oil thermal conductivity NANOPARTICLE
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High-Thermal Conductive Coating Used on Metal Heat Exchanger 被引量:10
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作者 李静 梁剧 刘业明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第5期596-601,共6页
Based on modified silicon polyester resin in addition to several functional fillers such as corrosion-resistant fillers, heat-resistant fillers and thermal conductive fillers, a high thermal conductive coating can be ... Based on modified silicon polyester resin in addition to several functional fillers such as corrosion-resistant fillers, heat-resistant fillers and thermal conductive fillers, a high thermal conductive coating can be made. On the basis of boronnitride(BN) and aluminum nitride(AIN) used as thermal conductive fillers and by means of the testing system of hot disk and heat transfer experiment, researches on the varieties of thermal conductive fillers and the effects of the contents of high-thermal conductive coating have been done, which shows that the thermal conductivity of coating increases with the increase of the quality fraction and the coefficient of thermal conductivity of the thermal conductive fillers of coating. With guaranteeing better heat resistance, stronger corrosion resistance and adhesive force, the coefficient of coating can reach a level as high as 3 W·m-1·K-1. 展开更多
关键词 thermal conductivity heat exchanger COATING
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Effect of Si content on microstructure and properties of Si/Al composites
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作者 翟蔚宸 张朝晖 +3 位作者 王富耻 神祥博 李树奎 王鲁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期982-988,共7页
Si/Al composites with different Si contents for electronic packaging were prepared by spark plasma sintering (SPS) technique. Properties of the composites were investigated, including density, thermal conductivity, ... Si/Al composites with different Si contents for electronic packaging were prepared by spark plasma sintering (SPS) technique. Properties of the composites were investigated, including density, thermal conductivity, coefficient of thermal expansion and flexural strength. The effects of the Si content on microstructure and thermal and mechanical properties of the composites were studied. The results show that the Si/Al composites consist of Si and Al components and Al uniformly distributes among Si grains. The relative density of the Si/Al composites gradually increases with the decrease of Si content and reaches 98.0% when the Si content is 50%. The thermal conductivity, the coefficient of thermal expansion and the flexural strength of the composite all decrease with the increase of the Si content, and an optimal matching of them is obtained when the Si content is 60%(volume fraction). 展开更多
关键词 spark plasma sintering Si/Al composite thermal conductivity coefficient of thermal expansion flexural strength
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Effect of Sr modification on microstructure and thermal conductivity of hypoeutectic Al−Si alloys 被引量:18
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作者 Jun-qi GAN Yu-jian HUANG +1 位作者 Cheng WEN Jun DU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第11期2879-2890,共12页
Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al... Trace amount of Sr(0.05 wt.%)was added into the hypoeutectic Al−Si(3−12 wt.%Si)alloys to modify their microstructure and improve thermal conductivity.The results showed that the thermal conductivity of hypoeutectic Al−Si alloys was improved by Sr modification,and the increment and increasing rate of the thermal conductivity gradually increased with Si content increasing.The improvement of thermal conductivity was primarily related to the morphology variation of eutectic Si phases.In Sr-modified Al−Si alloys,the morphology of eutectic Si phases was a mixed morphology of fiber structure and fine flaky structure,and the proportion of the fine flaky eutectic Si phases gradually decreased with Si content increasing.Under the Si content reaching 9 wt.%,the proportion of fine flaky eutectic Si phases was nearly negligible in Sr-modified alloys.Correspondingly,the increment and increasing rate of thermal conductivity of Sr-modified alloys reached the maximum and tended to be stable. 展开更多
关键词 hypoeutectic Al−Si alloy Sr modification eutectic Si morphology thermal conductivity Al/Si interface
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Influence of heat loss through probe electrical leads on thermal conductivity measurement with TPS method 被引量:3
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作者 WANG Yu-wei LI Yan-ning 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2018年第1期9-15,共7页
The transient plane source(TPS)method is developed recently to measure the thermal conductivity of materials.In the measurement,the heating power is influenced by the heat which is transferred via the probe electrical... The transient plane source(TPS)method is developed recently to measure the thermal conductivity of materials.In the measurement,the heating power is influenced by the heat which is transferred via the probe electrical leads.This fact further influences the measurement accuracy of thermal conductivity.To solve this problem,the influence of heat loss through the electrical leads on the heating power is studied theoretically.The mathematical formula of heat loss is deduced,and the corresponding correction model is presented.A series of measurement experiments on different materials have been conducted by using the hot disk thermal constant analyzer.The results show that the influence of the heat loss on the measurement is sensitive to different test materials and probes with different sizes.When the thermal conductivity of the material is greater than 0.2 W/(m·K),the influence of the heat loss is less than 0.16%,which can be ignored.As to the lower thermal conductivity materials,it is necessary to compensate the heat loss through the electrical leads,and the accuracy of thermal conductivity measurement can be effectively improved. 展开更多
关键词 transient plane source(TPS)method thermal conductivity heat loss through electrical leads heating power
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Analyses on performances of heat and multilayer reflection insulators 被引量:4
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作者 LEE Moo-jin LEE Kang-guk SEO Won-duck 《Journal of Central South University》 SCIE EI CAS 2012年第6期1645-1656,共12页
This research was conducted to study the performances of the heat and multilayer reflection insulators used for buildings in South Korea to realize eco-friendly, low-energy-consumption, green construction, and to cont... This research was conducted to study the performances of the heat and multilayer reflection insulators used for buildings in South Korea to realize eco-friendly, low-energy-consumption, green construction, and to contribute to energy consumption reduction in buildings and to the nation's greenhouse gas emission reduction policy (targeting 30% reduction compared to BAUCousiness as usual) by 2020). The heat insulation performance test is about the temperatures on surfaces of test piece. The high air temperature and the low air temperature were measured to determine the overall heat transfer coefficient and thermal conductivity. The conclusions are drawn that the heat transmission coefficients for each type of existing reflection insulator are: A-1 (0.045 W/(m-K)), A-2 (0.031 W/(m.K)), A-3 (0.042 W/(m.K)), A-4 (0.078 W/(m.K)), and the average heat conductivity is 0.049 W/(m-K); The heat conductivity for each type of Styrofoam insulator are 0.030 W/(m.K) for B-l, 0.032 W/(m-K) for B-2, 0.037 W/(m'K) for B-3, 0.037 W/(m.K) for B-4, and the average heat conductivity is 0.035 W/(m'K) regardless of the thickness of the insulator; The heat conductivity values of the multilayer reflection insulators are converted based on the thickness and type C-1 (0.020 W/(m.K)), C-2 (0.018 W/(m.K)), C-3 (0.016 W/(m.K)), and C-4 (0.012 W/(m.K)); The multilayer reflection insulator keeps the indoor-side surface temperature high (during winter) or low (in summer), enhances the comfort of the building occupants, and conducts heating and moisture resistance to prevent dew condensation on the glass-outer-wall surface. 展开更多
关键词 heat reflection insulator multilayer reflection insulator overall heat transfer coefficient thermal conductivity nonflammability vapor permeability eco-friendly construction
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Effect of graphitization degree of fuel cell gas diffusion layers on their heat management:Modeling and experiments 被引量:4
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作者 WU Xiao-bo YANG Piao-piao +3 位作者 GAO Ping-ping LIU Chun-xuan XIE Zhi-yong HUANG Qi-zhong 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第1期80-88,共9页
Serving as gas diffusion layers(GDLs),the thermal conductivity of carbon paper(CP)plays a significant role in the heat transfer management in fuel cells.In the present study,the effect of graphitization degree of CP o... Serving as gas diffusion layers(GDLs),the thermal conductivity of carbon paper(CP)plays a significant role in the heat transfer management in fuel cells.In the present study,the effect of graphitization degree of CP on its through plane thermal conductivity and in-plane thermal conductivity is investigated.The relationship between heat treatment temperatures(1800,2000,2200,2400 and 2500℃)and graphitization degree is also investigated by SEM,XRD and Raman measurements.A model for CP under different graphitization degree is suggested considering the thermal conductivity difference of carbon fiber and matrix carbon.The experimental and simulation results are compared.The results show that the graphitization degree has a significant impact on the through-plane thermal conductivity and in plane thermal conductivity. 展开更多
关键词 through-plane thermal conductivity graphitization degree heat transfer carbon papers
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Thermal conductivity of Al-Gd-TM glass-forming alloys 被引量:1
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作者 V.BYKOV S.UPOROV T.KULIKOVA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1911-1916,共6页
Thermal diffusivity, specific heat capacity and thermal conductivity of AI86Gd6TM8 (TM = Cu, Ni, Co, Fe, Mn, Cr, Ti, Zr, Mo, Ta) glass-forming alloys in the temperature range of 300-880 K were determined by laser fl... Thermal diffusivity, specific heat capacity and thermal conductivity of AI86Gd6TM8 (TM = Cu, Ni, Co, Fe, Mn, Cr, Ti, Zr, Mo, Ta) glass-forming alloys in the temperature range of 300-880 K were determined by laser flash method. The temperatures of endothermic and exothermic reactions of the alloys were determined by differential scanning calorimetry method. The alloys were prepared by conventional arc-melting technique under helium atmosphere. All the alloys studied exhibit strong supercooling of the liquidus temperatures up to 80 K, which indicates their good glass-forming ability. The specific heat capacity of the alloys achieves the Dulong-Petit's value in the temperature range of 350-550 K except Als6CrsGd6 and Als6ZrsGd6 compositions. The values of both thermal diffusivity and thermal conductivity of the alloy studied are significantly lower than those for pure aluminum. It is found that embedding 14% (mole fraction) of transition elements (Gd+TM) in the aluminum matrix leads to significant decrease in the absolute magnitudes of both thermal diffusivity and thermal conductivity in crystalline state. The thermal conductivity of glass-forming Als6Gd6TMs alloys is strongly affected by directed chemical bonding between alloy components. 展开更多
关键词 Al-based alloys thermal properties specific heat capacity thermal conductivity thermal diffusivity
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Thermal properties of closed-cell aluminum foams prepared by melt foaming technology 被引量:3
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作者 Hui WANG Xiang-yang ZHOU +2 位作者 Bo LONG Juan YANG Hong-zhuan LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第12期3147-3153,共7页
Closed-cell aluminum foam has incomparable advantages over other traditional materials for thermal insulation and heatpreservation because of small thermal conductivity coefficient. Spherical bubble three-dimensional ... Closed-cell aluminum foam has incomparable advantages over other traditional materials for thermal insulation and heatpreservation because of small thermal conductivity coefficient. Spherical bubble three-dimensional model of aluminum foam is builtto deduce the relationship among pore wall thickness, porosity and average pore size. Non-uniform closed-cell foam aluminummodel with different structural parameters and random pore distribution is established based on the relationship via C programminglanguage. And the temperature distribution is analyzed with ANSYS software. Results indicate that thermal conductivity increaseswith the reducing of porosity. For the aluminum foam with the same porosity, different pore distributions result in different thermalconductivities. The temperature distribution in aluminum foam is non-uniform, which is closely related with the pore size anddistribution. The pores which extend or distribute along the direction perpendicular to heat flow strengthen obstructive capability forheat flow. When pores connect along the direction perpendicular to heat flow, a “wall of high thermal resistance” appears to declinethe thermal conductivity rapidly, which shows that only porosity cannot completely determine effective thermal conductivity ofclosed-cell aluminum foam. 展开更多
关键词 closed-cell aluminum foam thermal conductivity POROSITY pore distribution temperature distribution
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Microstructure and properties of rheo-HPDC Al-8Si alloy prepared by air-cooled stirring rod process 被引量:5
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作者 Ming-fan QI Yong-lin KANG Guo-ming ZHU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第9期1939-1946,共8页
A new and effective semisolid slurry preparation process with air-cooled stirring rod(ACSR)is reported,in which the compressed air is constantly injected into the inner cavity of a stirring rod to cool the melt.The sl... A new and effective semisolid slurry preparation process with air-cooled stirring rod(ACSR)is reported,in which the compressed air is constantly injected into the inner cavity of a stirring rod to cool the melt.The slurry of a newly developed high thermal conductivity Al?8Si alloy was prepared,and thin-wall heat dissipation shells were produced by the ACSR process combined with a HPDC machine.The effects of the air flow on the morphology ofα1-Al particles,mechanical properties and thermal conductivity of rheo-HPDC samples were studied.The results show that the excellent slurry of the alloy could be obtained with the air flow exceeding3L/s.Rheo-HPDC samples that were produced with the air flow of5L/s had the maximum UTS,YS,elongation,hardness and thermal conductivity of261MPa,124MPa,4.9%,HV99and153W/(m·K),respectively.Rheo-HPDC samples show improved properties compared to those formed by HPDC,and the increasing rates of UTS,YS,elongation,hardness and thermal conductivity were20%,15%,88%,13%and10%,respectively. 展开更多
关键词 rheo-HPDC Al.8Si alloy air-cooled stirring rod microstructure mechanical properties thermal conductivity
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Significance of induced magnetic field and variable thermal conductivity on stagnation point flow of second grade fluid 被引量:2
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作者 A.A.KHAN S.ILYAS +1 位作者 T.ABBAS R.ELLAHI 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第11期3381-3390,共10页
In this study,the stagnation point transport of second grade fluid with linear stretching under the effects of variable thermal conductivity is considered.Induced magnetic field impact is also incorporated.The nonline... In this study,the stagnation point transport of second grade fluid with linear stretching under the effects of variable thermal conductivity is considered.Induced magnetic field impact is also incorporated.The nonlinear set of particle differential equations is converted into set of ordinary differential equations through appropriate transformation.The resulting equations are then resolved by optimal homotopy analysis method.The effect of pertinent parameters of interest on skin friction coefficient,temperature,induced magnetic field,velocity and local Nusselt number is inspected by generating appropriate plots.For numerical results,the built-in bvp4 c technique in computational software MATLAB is used for the convergence and residual errors of obtained series solution.It is perceived that the induced magnetic field is intensified by increasing β.It can also be observed that skin friction coefficient enhances with increasing value of magnetic parameter depending on the stretching ratio a/c.For the validness of the obtained results,a comparison has been made and an excellent agreement of current study with existing literature is found. 展开更多
关键词 stagnation point variable thermal conductivity induced magnetic field second grade fluid
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