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181.
In this paper three‐dimensional lubrication flow of grease is analysed numerically. The lubrication flow configuration is formed by two ellipsoid rollers. The load is assumed to be light enough for the lubrication mode to be purely hydrodynamic. The fluid behaviour is modelled using the Herschel–Bulkley model, and a two‐dimensional modified Reynolds equation is derived. The numerical solutions are obtained by using a hybrid spectral/iterative technique and the Galerkin projection scheme. The effects of the material and geometrical parameters on pressure distribution are emphasized in the study. The investigation is conducted for a situation where the two ellipsoids are fully immersed in a grease lubricant. The effect of the geometry on the pressure distribution is determined by varying the ratio of the semi‐axes and the minimum gap of the two rollers, respectively. The effect of the material parameters is examined by varying the power‐law index and yield stress. It is found that the pressure distribution is strongly influenced by the shape of the rollers, the size of the minimum gap of the rollers and the rheological parameters. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
182.
本文根据谐波平衡法假设周期解的基本思想,提出了一种分析非线性振动特性的正交函数法。将位移展开为谐波的级数形式,根据线性模态和三角级数的正交性导出了一组形式简单的特征方程。有效地解决了平方非线性系统存在漂移项的困难,算例表明:本文方法精度高,收敛快,工作量小。 相似文献
183.
Juan A. Navarro Gonzalez Juan B. Sancho de Salas 《Journal of Geometry and Physics》2003,44(4):595-622
We consider a smooth one-parameter family of four-dimensional manifolds X,≥0, each one endowed with a covariant metric g. It is assumed that g is a Lorentz metric for each >0, i.e., the signature of g is (+,−,−,−) for >0, while the limit metric g0 on X0 is assumed to be degenerated of rank 1, i.e., the signature of g0 is (+,0,0,0). We characterize when the limit manifold X0 inherits the geometric structure of a Newtonian gravitation. The limit manifold X0 is a Newtonian gravitation if and only if there exist the limits of the Levi-Civita connection , the curvature operator
and the contravariant Einstein tensor G2 as →0. Moreover, the existence of these limits is characterized in terms of the Taylor expansion of the family {g} with respect to the parameter . 相似文献
184.
The optical nonlinearity of low-dimension structures is studied in the self-effect case at a wavelength of 630 nm in a range of light intensities below 0.1 W/cm2 by waveguide methods. Common tendencies in relationships between intensity of light and optical properties of multilayer structures and semiconductor-doped glass films are detected. It is shown that the state of interfaces determines the character of optical nonlinearity. 相似文献
185.
A method and an algorithm for determining the effective deformational properties of dispersely strengthened materials with a physically nonlinear matrix and quasi-spheroidal linearly elastic inclusions are elaborated based on the stochastic differential equations of the physically nonlinear theory of elasticity. Their transformation to integral equations and the application of the method of conditional moments reduce the problem to a system of nonlinear algebraic equations, whose solution is constructed by the iteration method. The deformation diagrams as functions of the volume content of inclusions are investigated. 相似文献
186.
在北京正负电子对撞机的J/ψ和Ds能区,选择了辐射巴巴事例,并以此来研究北京谱仪的桶部簇射计数器能量响应特性.在消除了由于电子和辐射光子在桶部簇射计数器中沉积能量区域重叠的影响后,正确地得到了桶部簇射计数器在电子和光子动量小于2GeV以下的能量响应,表明在所研究能区,桶部簇射计数器的能量响应线性很好.对桶部簇射计数器微小的非线性进行修正后,重建的π0不变质量谱得到改善. 相似文献
187.
Soichiro Katayama 《Journal of Differential Equations》2005,209(1):140-171
We consider the Cauchy problem for systems of nonlinear wave equations with different propagation speeds in three space dimensions. We prove global existence of small amplitude solutions for systems with some nonresonant nonlinearities which may depend on both of the unknowns and their derivatives. Our method here can be also adopted to treat the null forms. 相似文献
188.
We report on the 320 Gb/s (40 Gb/s × 8 channels) WDM transmission experiment using short-period dispersion-managed fiber. After 320-km transmission, the average Q-factor was measured to be better than 20.4 dB. In addition, we compared the performances of various types of fibers in 40-Gb/s based systems. The results show that the SPDMF was robust to both the intra-channel and inter-channel nonlinearities due to its small average dispersion and large local dispersion. 相似文献
189.
采用脉冲激光沉积(PLD)技术在MgO基片上制备了金属Fe薄膜.利用原子力显微镜研究了不同制备温度对薄膜表面形貌的影响.x射线衍射分析表明沉积温度大于500℃时,Fe薄膜在MgO基片上有很好的结晶性,并有单一取向.通过z扫描方法测量了超薄Fe膜的光学非线性,得到了Fe薄膜的非线性折射率n2=709×10-5cm2/ kW,非线性吸收系数 β=-552×10-3cm/W.
关键词:
Fe薄膜
非线性
脉冲激光沉积 相似文献
190.