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111.
In the theory of elastic thin plates, the bending of a rectangular plate on the elastic foundation is also a difficult problem. This paper provides a rigorous solution by the method of superposition. It satisfies the differential equation, the boundary conditions of the edges and the free corners. Thus we are led to a system of infinite simultaneous equations. The problem solved is for a plate with a concentrated load at its center. The reactive forces from the foundation should be made to be in equilibrium with the concentrated force to see whether our calculation is correct or not. 相似文献
112.
113.
Nataliya E. Borisova Marina A. Orlova Valery A. Knizhnikov Varvara K. Dolgova Marina D. Reshetova Alexey P. Orlov 《Mendeleev Communications》2021,31(2):207-209
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114.
Ruiqi Yin Xiaochen Zhang Jianxian Ge Ling Wen Lei Chen Jianfeng Zeng Zhen Li Mingyuan Gao 《Particle & Particle Systems Characterization》2021,38(1):2000270
The rapid growth of inorganic nanoparticles provides numerous opportunities for cancer diagnosis. Due to their adjustable and diverse characteristics that are strongly dependent on the size, morphology, charge, and the nature of surface coatings, they are widely used in the field of oncology. However, inorganic nanomaterials are usually difficult to degrade and excrete within a short time, resulting in long-term in vivo retention and potential toxicity, which significantly hinders their translation into clinical practice. Therefore, the development of renal clearable inorganic nanomaterials that can excrete out of body within desired timeframe is of great significance to promote their clinical bioapplications. Herein, the recent advances in renal clearable inorganic nanoparticles for tumor diagnosis are focused on, and the factors affecting the renal clearance efficiency, with a view to understand the underlying metabolism mechanism and the relevant bioapplications, are discussed. 相似文献
115.
The results of an investigation of the flow past and the behavior of free bluff bodies mounted in pipes and channels with a narrow clearance, conducted in the Institute of Mechanics of Moscow State University, are presented. The drag of circular cylinders of different size and mass in a circulation-free water flow in a plane channel of rectangular cross-section was studied in the transverse self-oscillation regime. The experiments were conducted for Reynolds numbers based on the cylinder diameter 1.7 ? 104 ≤ Re ≤ 7.2 ? 104, relative clearances \(\bar S\) based on a cross-sectional area ranging from 0.76 to 0.9, and cylinder-to-water density ratios ρ c /ρ ranging from 1.29 to 8.2. Only the case of intense transverse self-oscillations accompanied by impact interaction with the channel wall was considered. The dependence of the period-average cylinder drag coefficient C x on the basic dimensionless relevant parameters is obtained. The dependence of the dimensionless self-oscillation frequency determined in [1] is refined. The kinematic and dynamic features of the flows past spheres in cylindrical pipes and cylinders in plane channels are compared in the transverse self-oscillation regime. 相似文献
116.
利用 Laplace 变换确定双层厚壁长圆筒的轴对称界面碰撞压力 总被引:1,自引:0,他引:1
利用Laplace变换,考虑轴对称弹性波的影响,采用特征函数展开法求解双层厚壁长圆筒受爆炸载荷作用下的轴对称弹性碰撞冲击问题,着重研究前几次碰撞冲击引起的轴对称界面碰撞压力。并对轴对称界面碰撞压力与间隙量、爆炸载荷幅值、爆炸载荷衰减系数之间的关系以及相关的动力响应作了初步的分析。 相似文献
117.
By means of ink trace visualization of the flows in conventional straight, positively curved and negatively curved cascades
with tip clearance, and measurement of the aerodynamic parameters in transverse section, and by appling topology theory, the
topological structures and vortex structure in the transverse section of a blade cascade were analyzed. Compared with conventional
straight cascade, blade positive curving eliminates the separation line of the upper passage vortex, and leads the secondary
vortex to change from close separation to open separation, while blade negative curving effects merely the positions of singular
points and the intensities and scales of vortex.
Foundation items: 973 Project of China; the Doctoral Foundation of Education Ministry of China (EDAF24403003)
Biography: YANG Qing-hai (1969−) 相似文献
118.
A HB (Harmonic Balance)/AFT (Alternating Frequency/Time) technique is developed to obtain synchronous and subsynchronous whirling motions of a horizontal Jeffcott rotor with bearing clearances. The method utilizes an explicit Jacobian form for the iterative process which guarantees convergence at all parameter values. The method is shown to constitute a robust and accurate numerical scheme for the analysis of two dimensional nonlinear rotor problems. The stability analysis of the steady-state motions is obtained using perturbed equations about the periodic motions. The Floquet multipliers of the associated Monodromy matrix are determined using a new discrete HB/AFT method. Flip bifurcation boundaries were obtained which facilitated detection of possible rotor chaotic (irregular) motion as parameters of the system are changed. Quasi-periodic motion is also shown to occur as a result of a secondary Hopf bifurcation due to increase of the destabilizing cross-coupling stiffness coefficients in the rotor model. 相似文献
119.
NONLINEAR STABILITY OF BALANCED ROTOR DUE TO EFFECT OF BALL BEARING INTERNAL CLEARANCE 总被引:2,自引:0,他引:2
Stability and dynamic characteristics of a ball bearing-rotor system are investigated under the effect of the clearance in the ball bearing. Different clearance values are assumed to calculate the nonlinear stability of periodic solution with the aid of the Floquet theory. Bifurcation and chaos behavior are analyzed with variation of the clearance and rotational speed. It is found that there are three routes to unstable periodic solution. The period-doubling bifurcation and the secondary Hopf bifurcation are two usual routes to instability. The third route is the boundary crisis, a chaotic attractor occurs suddenly as the speed passes through its critical value. At last, the instable ranges for different internal clearance values are described. It is useful to investigate the stability property of ball bearing rotor system. 相似文献
120.