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991.
992.
Chen Huai 《中国科学基金(英文版)》2008,16(1):2-2
Prof. Wang Jie, NSFC Vice President, cordially met with Dr. David Lightfoot, Assistant Director of USA National Science Foundation (NSF) responsible for the Directorate for Social, Behavioral and Economic Sciences, on April 21, 2008. 相似文献
993.
苏丹共和国麦罗维友谊大桥设计 总被引:1,自引:0,他引:1
文章介绍了麦罗维友谊大桥的构造和预应力体系设计,并对该桥的总体设计、结构内力分析以及箱梁施工程序等方面进行了介绍。 相似文献
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《电子CAD-PROTEL》课程的教学改革探索 总被引:2,自引:0,他引:2
本文首先介绍了电子CAD-PROTEL课程的教学现状,对传统的教学模式所存在的弊端,提出了具体的改革措施和方法。改革目标是要提高和增强学生学习的主动性与实践能力,培养学生的创新思维和创新能力,让学生能独立地将理论知识应用到工程实际中去,实践证明这些改革收到了良好的教学效果。 相似文献
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999.
TAO PingJun YANG YuanZheng BAI XiaoJun XIE ZhiWei CHEN XianCao DONG ZhenJiang Wen JianGuo 《科学通报(英文版)》2008,53(3):465-468
Generally, bulk metallic glasses (BMGs) exhibit a very limited plastic deformation under a compression load at room temperature, often less than 2% before fracturing. In this letter, through an appropriate choice of BMGs' composition, an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting. X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability, and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously. The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K, respectively, and its micro-hardness was 594.7 Hv. During compression, when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa, respectively, i.e., the true strain and true stress reached 9.42% and 1560 MPa, respectively, the amorphous rod started to yield. After yielding, with the increase of load, the strain increased and the glass rod ulti- mately were compressed into flake-like form. Although the maximum engineering strain was larger than 70%, i.e., the maximum true strain exceeded by 120%, the amorphous specimen was not fractured, indicating that it has super-plasticity at room temperature. Through the appropriate choice of composition and optimization of the technological process, flexible BMG with super-plasticity at room temperature could be produced. 相似文献
1000.
Relationship between the atmospheric heat source over Tibetan Plateau and the heat source and general circulation over East Asia 总被引:4,自引:0,他引:4
On the basis of NCEP/NCAR version I daily reanalysis data from 1971 to 2000 and by the methods of inverse calculation, correlation analysis and comparative analysis, the influences of atmospheric heat source (AHS) over the Tibetan Plateau on the large-scale AHS and the general circulation in summer are studied in this paper. The results show that AHS over the plateau in summer may trigger a heat source wavetrain propagating northeastward along the coast from the East Asian continent and West Pacific to Bering Strait-Arctic or even North America. In addition, if AHS over the eastern plateau is intense, South Asian High moves to southeast and West Pacific subtropical high moves to southwest; on the contrary, if AHS over the eastern plateau is weak, South Asian High moves to northwest and West Pacific subtropical high moves to northeast. Therefore, South Asian High and West Pacific subtropical high move in the horizontally-opposite directions in terms of interannual variation, for which AHS over the eastern plateau seems to be thermodynamically responsible. 相似文献