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991.
Some experiments were made for the buoyant jet from a square orifice with a square disc placed on it in static ambient and concentration along the axis in self-similar area behind disc was measured. And at the same time a three-dimensional mathematical model was established to simulate the whole flowing under different conditions. All the results predicted by the numerical calculation were substantiated by the experiments. The results were compared with experiential formula for obstructed round buoyant vertical jets in static ambient and it was found that the two concentration distributions had good accordance. Star shape of temperature isolines on cross-sections in the near areas from the disc was found and it was a very special figure for obstructed square buoyant vertical jets with a square disc. The shape will transform to concentric circles gradually alike to the round buoyant vertical jet in self-similar area with increasing of the distance from the disc. 相似文献
992.
戴世强 《应用数学和力学(英文版)》1991,12(7):617-625
In this paper,we reexamine the method of successive approximation presented byProf.Chien Wei-zang for solving the problem of large deflection of a circular plate,and findthat the method could be regarded as the method of strained parameters in the singularperturbation theory.In terms of the parameter representing the ratio of the centerdeflection to the thickness of the plate,we make the asymptotic expansions of thedeflection,membrane stress and the parameter of load as in Ref.[1],and then give theorthogonality conditions(i.e.the solvability conditions)for the resulting equations,bywhich the stiffness characteristics of the plate could be determined.It is pointed out thatwith the solutions for the small deflection problem of the circular plate and theorthogonality conditions,we can derive the third order approximate relations between theparameter of load and the center deflection and the first-term approximation of membranestresses at the center and edge of the plate without solving the differential equ 相似文献
993.
将零厚度单向试件栅刻蚀工艺应用于晶须增韧氮化硅陶瓷基复合材料表面,通过记录试件所在桥路的输出电压值,可得到随载荷不断增大裂纹逐渐向前扩展过程中每一时刻的裂尖位置和裂纹长度,从而得到该种材料的阻力曲线。 相似文献
994.
Hole-drilling method is one of the most convenient methods for engineering residual stress measurement. Combined with moiré
interferometry to obtain the relaxed whole-field displacement data, hole-drilling technique can be used to solve non-uniform
residual stress problems, both in-depth and in-plane. In this paper, the theory of moiré interferometry and incremental hole-drilling
(MIIHD) for non-uniform residual stress measurement is introduced. Three dimensional finite element model is constructed by
ABAQUS to obtain the coefficients for the residual stress calculation. An experimental system including real-time measurement,
automatic data processing and residual stresses calculation is established. Two applications for non-uniform in-depth residual
stress of surface nanocrystalline material and non-uniform in-plane residual stress of friction stir welding are presented.
Experimental results show that MIIHD is effective for both non-uniform in-depth and in-plane residual stress measurements.
The project supported by the FRAMATOME ANP 相似文献
995.
996.
In literature, nonlinear traveling waves in elastic circular rods have only been studied based on single partial differential
equation (pde) models, and here we consider such a problem by using a more accurate coupled-pde model. We derive the Hamiltonian
from the model equations for the long finite-amplitude wave approximation, analyze how the number of singular points of the
system changes with the parameters, and study the features of these singular points qualitatively. Various physically acceptable
nonlinear traveling waves are also discussed, and corresponding examples are given. In particular, we find that certain waves,
which cannot be counted by the single-equation model, can arise.
The project supported by the Research Grants Council of the HKSAR, China (City U 1107/99P) and the National Natural Science
Foundation of China (10372054 and 10171061) 相似文献
997.
本文将两相流动的雷诺方程沿深度方向进行平均,出求了平均后的运动方程、连续方程和能量方程式,在适当的物理假定下,简化得到可适用于考虑固-液流动及气-液流动两种情况下的两相层状流动基本方程. 相似文献
998.
999.
Synthesis of Nitrogen‐Doped Mesoporous Carbon Spheres with Extra‐Large Pores through Assembly of Diblock Copolymer Micelles 下载免费PDF全文
Jing Tang Dr. Jian Liu Dr. Cuiling Li Yunqi Li Prof. Moses O. Tade Prof. Sheng Dai Prof. Yusuke Yamauchi 《Angewandte Chemie (International ed. in English)》2015,54(2):588-593
The synthesis of highly nitrogen‐doped mesoporous carbon spheres (NMCS) is reported. The large pores of the NMCS were obtained through self‐polymerization of dopamine (DA) and spontaneous co‐assembly of diblock copolymer micelles. The resultant narrowly dispersed NMCS possess large mesopores (ca. 16 nm) and small particle sizes (ca. 200 nm). The large pores and small dimensions of the N‐heteroatom‐doped carbon spheres contribute to the mass transportation by reducing and smoothing the diffusion pathways, leading to high electrocatalytic activity. 相似文献
1000.
Nuo Duan Shijia Wu Shaoliang Dai Tingting Miao Jie Chen Zhouping Wang 《Mikrochimica acta》2015,182(5-6):917-923