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991.
sented to correct for the shape effects. 相似文献
992.
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. 相似文献
993.
994.
The collision efficiency of dioctyl phthalate nanoparticles in Brownian coag- ulation has been studied. A set of collision equations is solved numerically to find the relationship between the collision efficiency and the particle radius varying in the range of 50 nm to 500 nm in the presence of Stokes resistance, lubrication force, van der Waals force, and elastic deformation force. The calculated results are in agreement with the experimental data qualitatively. The results show that the collision efficiency decreases with the increase of the particle radii from 50 nm to 500 nm. Based on the numerical data, a new expression for collision efficiency is presented. 相似文献
995.
A two fluid continuum model is applied to the simulation of steady fully developed particle/fluid flow in a vertical circular pipe. Both closed form and numerical solutions are obtained to the associated governing equations. These solutions are compared to the predictions of another two fluid continuum model. These comparisons are used to illustrate the differences in the predictions of two widely used models, even in the fundamental problem of steady flow in a circular pipe. 相似文献
996.
Yunxiaing You Tianqun Hu Hao Xu Yongliu Fang Zhong Yu Zhongmin Shi Yan Qu Yue Xiao 《力学学报》2010,42(3):400
对密度分层流体中内波与半潜平台的相互作用问题
进行了模型试验研究. 采用摇板方法进行了内波造波试验,对内波波长、周期和波高进行了
测量分析,获得了内波波高和波长与周期之间的相关关系. 利用激光和倾角仪方法对半潜平
台的纵荡和纵摇运动响应进行了测量分析,获得了平台纵荡运动及纵摇角幅值与内波周期之
间的相关关系. 结果表明,在半潜平台的设计与应用中,内波对其运动响应的影响是不可忽
视的. 特别地,发现了在内波周期的某个范围内, 半潜平台的纵荡和纵摇都会出现
倍频周期运动响应的现象. 相似文献
997.
A molecular dynamics simulation of segregation behaviours of horizontally vibrated binary granular mixture 下载免费PDF全文
This paper performs the two-dimensional, soft-sphere
molecular dynamics simulations to study the granular segregation in
a binary granular mixture with the same size but different density
in the container with the sawtooth base under horizontal vibration.
The segregation phase diagram is presented in the
acceleration-frequency space. When the acceleration is high enough
to result in relative motions of the particles, the system can be in
various states (mixed state, vertical and horizontal segregation
state), which depend on both acceleration and frequency. Due to the
sawtooth base there is stratified flow effect besides density
effect. The density effect raises the light particles. The
stratified flow drives the particles in the upper levels to the
right and the particles in the lower particles to the left, those
fact results in the appearance of the left segregation state. The
left segregation state can be changed to the right segregation by
changing the shape of the sawtooth. As the vibration frequency
increases, the stratified flow effect becomes weaker and weaker, so
at high vibration frequencies the vertical segregation state appears
instead of the left segregation state. 相似文献
998.
In this paper, we study the Hopf bifurcation for the four-dimensional competitive Lotka–Volterra system, and give an example which can display chaotic dynamics apparent like Rössler’s folded band attractor. This demonstrates that Smale’s conclusions in (J. Math. Biol., 3:5–7, 1976) are true even for the simplest competitive Lotka–Volterra systems when the dimension n is four. We explore the mechanism of occurrence of chaotic behavior for the four-dimensional competitive Lotka–Volterra system. The numerical study indicates that a periodic solution by Hopf bifurcation can undergo successive period-doubling cascades, and a homoclinic orbit can undergo homoclinic bifurcation by Shil’nikov theorem. 相似文献
999.
For an operator weighted shift S, the essential spectrum σ
e (S) are described. Moreover, Banach reducibility of S is investigated and a condition for S* to be a Cowen-Douglas operator is characterized.
Supported by MCME, Doctoral Foundation of the Ministry of Education and Science Foundation of Liaoning
University 相似文献
1000.
In this paper we prove the persistence of lower-dimensional invariant tori of integrable equations after Hamiltonian perturbations under the first Melnikov's non-resonance condition. The proof is based on an improved KAM machinery which works for the angle variable dependent normal form. By an example, we also show the necessity of the Melnikov's first non-resonance condition for the persistence of lower dimensional tori. 相似文献