82 resultados para 21-206

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Peel test measurements and simulations of the interfacial mechanical parameters for the Al/Epoxy/Al2O3 system are performed in the present investigation. A series of Al film thicknesses between 20 and 250 microns and three peel angles of 90, 135 and 180 degrees are considered. Two types of epoxy adhesives are adopted to obtain both strong and weak interface adhesions. A finite element model with cohesive zone elements is used to identify the interfacial parameters and simulate the peel test process. By simulating and recording normal stress near the crack tip, the separation strength is obtained. Furthermore, the cohesive energy is identified by comparing the simulated steady-state peel force and the experimental result. It is found from the research that both the cohesive energy and the separation strength can be taken as the intrinsic interfacial parameters which are dependent on the thickness of the adhesive layer and independent of the film thickness and peel angle.

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<正> 一、力学发展的趋势 1.20世纪力学的巨大成就 本世纪初边界层理论的提出,对力学的发展起了划时代的作用。从此,流体力学能够成功地解释流动对物体的阻力与升力,为航空、航天的发展奠定了科学基础。这个典型也影响与推动了其他力学分支的发展,使力学研究的内涵有了空前的充实、扩大与深化。早在20年代初便形成了活跃于整个20世纪内容广泛的应用力学,成为工程与应用科学的支柱。人们把空气动力学的研究看作是本世纪以科学为基础将航

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回顾力学发展史,阐明在科技发展过程中力学对于认识自然规律和解决工程技术问题中的地位和作用;提出在固体力学、流体力学、一般力学以及有关力学的若干交叉学科领域中的一些重要研究课题;展望21世纪(特别是21世纪前期)的力学发展趋势.

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回顾力学发展史,阐明在科技发展过程中力学对于认识自然规律和解决工程技术问题中的地位和作用;提出在固体力学、流体力学、一般力学以及有关力学的若干交叉学科领域中的一些重要研究课题;展望21世纪(特别是21世纪前期)的力学发展趋势。

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回顾力学发展史,阐明在科技发展过程中力学对于认识自然规律和解决工程技术问题中的地位和作用,提出在固体力学、流体力学、一般力学以及有关力学的若干交叉学科领域中的一些重要研究课题;展望21世纪(特别是21世纪前期)的力学发展趋势。

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扼要地介绍了自1976年以来,在血栓形成研究中的进展及其对21世纪的展望。

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<正>力学是力与运动的科学,它研究的对象主要是物质的宏观机械运动,它既是基础科学,又是众多应用科学,特别是工程技术的基础。它过去建立在牛顿定律和经典热力学的基础上,现在则扩大到量子力学描述的微观层次。力学和天文学、微积分学几乎同时诞生,曾在经典物理的发展中起关键作用。20世纪力学在推动地球科学,如大气物理、海洋科学等的定量化方面,作出了重大贡献。近年来还在材料科学、生物学、医学等科学分支中起着越来越重要的作用。

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Special thanks to Christopher Blair and Mumtaz Baig for their suggestions. This work was supported by National Basic Research Program of China (973 Program, 2007CB411600), National Natural Science Foundation of China (30621092), and Bureau of Science and Technology of Yunnan Province.

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<正> 世界鲸类动物的人工饲养已经有100多年的历史,鲸类动物的人工饲养不但为人们提供了一种非常有趣的娱乐项目,而且为深入研究、繁殖和保护鲸类动物提供了很好的条件。我国鲸类动物的人工饲养于1965年由青岛海产博物馆从饲养江豚开始

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采用热休克调控技术诱导出103尾第一代白鲫(♀)×红鲫()异源四倍体鱼,并对其生殖力进行了研究。1或2龄的四倍体雄鱼能产生精子,而雌鱼不能产生正常的卵。将异源四倍体雄鱼与二倍体白鲫雌鱼交配产生倍间三倍体鱼,染色体检查证明是整三倍体(3N=150),但其受精率很低(11.4—51.3%,平均32.4%).网箱养殖结果表明,倍间三倍体白鲫的生长速度比白鲫快30%以上,雌雄均不育.并用冷休克处理回收异源四倍体4N()×白鲫2N(♀)受精卵的第二极体产生了新的四倍体鱼.文中还对第一代异源四倍体鱼的批量生产、生殖能

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Aluminum nitride (AIN) thin films were deposited on Si (111) substrates by low pressure metalorganic chemical vapor deposition system. The effects of the V/III ratios on the film structure and surface morphology were systematically studied. The chemical states and vibration modes of AIN films were characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. The optical absorption property of the AIN films, characterized by ultraviolet-visible-near infrared spectrophotometer, exhibited a sharp absorption near the wavelength of 206 mm. The AIN (002) preferential orientation growth was obtained at the V/III ratio of 10,000 and the preferential growth mechanism is presented in this paper according to the thermodynamics and kinetics process of the AIN growth.