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M. Song D.H. Xiao State Key Laboratory of Powder Metallurgy Central South University Changsha China 《金属学报(英文版)》2007,(6)
The ab initio method has been performed to explore the elastic and optical properties of Al3Sc compound, based on a plane wave pseudopotential method. It can be seen that the calculated equilibrium lattice parameter and elastic constants are in reasonable agreement with the previous experimental data. The elastic constants satisfy the requirement for mechanical stability in the cubic structure of the Al3Sc compound. The optical property calculations show that a strong absorptive peak exists from 0-15eV and a relative small absorptive peak exists around 30eV. The form is caused by the optical transitions between high s, p, and d bands, and the latter results from the optical transitions from high s, p, and d bands to the low 2p band. 相似文献
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利用DEAE—Sephadex分离柱及GC—MS对构树皮丙酮抽出物 进行了分离和分析.在丙酮抽出物中中性组分占抽出物的59.7%,弱酸性 组分和强酸性组分分别占25.9%和10.3%.中性组分中不皂化物占 89.2%,皂化物仅占8.4%.不皂化物的成分比较复杂,所检出的主要有 甾醇和甾酮类.皂化物中亚油酸占50%,软脂酸占21%.弱酸性组分中 50%以上是脂肪酸(亚油酸和软脂酸),而没有松香酸. 相似文献
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JIANG YuXuan LI Zheng SUN YongJian YU TongJun CHEN ZhiZhong ZHANG GuoYi ZHANG GuangChen & FENG ShiWei State Key Laboratory of Artificial Microstructure Mesoscopic Physics School of Physics Peking University Beijing China School of Electronic Information & Control Engineering Beijing University of Technology Beijing 《中国科学:信息科学(英文版)》2010,(2)
We presented the analysis of the incomplete conduction in bonding medium in high power GaN-based light-emitting diode (LED) packages. A numerical study was carried out with parametric model to understand the junction temperature variation due to bonding medium defects. Transient thermal measurement was performed to evaluate LED’s junction temperature. Thermal resistance from chip to lead frame was 20 K/W in our sample LED. It was suggested that only 60% of the surface area of the bonding medium was involved... 相似文献
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NISHI Michihiro 《中国科学:信息科学(英文版)》2010,(1)
A novel double suction shaft-less mini pump was developed for heat control of small energy systems in this study.The mini pump impeller with an exit diameter of 40 mm was combined with the motor rotor supported by the hybrid dynamic bearing.The specific speed of the pump was 125 min-1 m3 min-1 m.The hydraulic performance of the pump was investigated experimen-tally under four rotational speeds.From the test results,it was recognized that the pump could provide a flow discharge of 5 L/min and head of 1.5 m,w... 相似文献
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Ji-ping Chen) Yong-lin Kang ) Ying-min Hao) Guang-ming Liu) Ai-ming Xiong) ) School of Materials Science Engineering University of Science Technology Beijing Beijing China ) The State Key Laboratory for Advanced Metals Materials China ) Steel Research Institute of Shougang Beijing China 《北京科技大学学报(英文版)》2009,16(5):540-548
A Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied.Subsequent cold rolling and continuous annealing processes were also conducted.The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites.The yield strength,ultimate tensile strength,n value,and r value of the No.2 specimen hot-rolled in the ferr... 相似文献
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ZHANG YuJun ZHANG WeiQing & YANG ChaoShuai State Key Laboratory of Geomechanics Geotechnical Engineering 《中国科学:信息科学(英文版)》2011,(7)
With the models of stress corrosion and pressure solution, by Yasuhara et al., two computation conditions were designed for a hypothetical nuclear waste repository in an unsaturated dual-porosity rock mass: (i) the fracture apertures are changed with the stress corrosion and pressure solution (the porosity of rock matrix is also a function of stress); (ii) the fracture apertures and the porosity of rock matrix are constants. Then the corresponding two-dimensional FEM analyses for the coupled thermohydro-mec... 相似文献
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DALLY B B 《中国科学:信息科学(英文版)》2011,(2)
Moderate or intense low oxygen dilution(MILD)combustion plays a significant role in the mitigation of combustion-generated pollutants and greenhouse gases whilst meeting thermal efficiency needs.However,due to the lack of the fundamental knowledge on this combustion,there is a misconception that MILD combustion should be established by high preheating of the air,which has limited its application.Our research and development on this combustion has been performed for several years. We have found that the requ... 相似文献