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In this article we use the C 1 wavelet bases on Powell-Sabin triangulations to approximate the solution of the Neumann problem for partial differential equations. The C 1 wavelet bases are stable and have explicit expressions on a three-direction mesh. Consequently, we can approximate the solution of the Neumann problem accurately and stably. The convergence and error estimates of the numerical solutions are given. The computational results of a numerical example show that our wavelet method is well suitable to the Neumann boundary problem. 相似文献
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Sami Ullah Khan Samaira Aziz Hiba Hussein Alwan Muapper Alhadri Shaher Alshammrei Yassine Bouazzi 《印度化学会志》2022,99(8):100616
Recently, the nanofluids report multidisciplinary applications in the various era of engineering like engine cooling, solar energy production, cooling of engineering devices, diesel generator performance etc. Owing to such novel applications, the aim of current communication is to report the significances of bio-convection for unsteady Eyring Powell nanofluid due to bidirectional oscillatory stretching surface. The enrollment of buoyancy forces and magnetic impact are worked out to inspect the stability and thermal on set of nanofluids. Heat transformation features are explored by utilizing thermal radiation. Further, the characteristics of chemical reaction and activation energy have been considered for physical significance. Unlike traditional approach, the governing equations are not altered into ordinary set of equation but only diminish the independent variables. This task makes the non-dimensional equations in highly complicated from which the convergent technique via HAM is successfully implemented. The physical outcomes of dominant variables on profiles of microorganisms, concentration, temperature, velocity and skin frictions are conferred graphically while local motile density, Sherwood and Nusselt numbers are deliberated through different tables. It is noted that the amplitude of bidirectional shear stresses and velocities periodically get increase for higher material parameter. This analysis emphasized that concentration distribution augments for rising values of activation energy variable, whereas conflicting situation occurs for temperature difference parameter. Moreover, motile microorganism's distributions are diminished by improved values of bio-convected Peclet and bio-convected Lewis numbers. 相似文献
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Shangyou Zhang 《计算数学(英文版)》2008,(3):456-470
The stability of the P1-P0 mixed-element is established on general Powell-Sabin triangular grids. The piecewise linear finite element solution approximating the velocity is divergence-free pointwise for the Stokes equations. The finite element solution approximating the pressure in the Stokes equations can be obtained as a byproduct if an iterative method is adopted for solving the discrete linear system of equations. Numerical tests are presented confirming the theory on the stability and the optimal order of convergence for the P1 Powell-Sabin divergence-free finite element method. 相似文献
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基于Powell优化算法和图像的金字塔分解,提出了一个新的亚像元运动参数估计方法.用参考图像和待配准图像构造的非线性最小二乘公式作为Powell算法的目标函数,并且以运动参数作为变量.由细到粗的多分辨率分解为准确的亚像元参数估计提供了基础.数值实验结果表明,该算法可以用于准确的稳健的亚像元参数估计,其不足之处在于运行时间比较长. 相似文献
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We trace the history of physics in Bristol, before and after the foundation of the University, describing the important locations
and events and contributions by notable individuals. As well as the Nobel prizewinners Paul Dirac, Cecil Powell, and Nevill
Mott, these include Arthur Tyndall, Charles Frank, Yakir Aharonov, and David Bohm.
For detailed historical material and personal reminiscences relating to the Bristol Physics Department, see the website <http://www.phy.bris.ac.uk/history.html>.
Michael Berry and Brian Pollard have been members of the theory group in the Physics Department of the University of Bristol
since the 1960s. 相似文献
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Powell dynamic identification of displacement parameters of indeterminate thin-walled curve box based on FCSE theory 总被引:1,自引:0,他引:1
Jian Zhang · Chu-Wei Zhou · Jia-Shou Zhuo College of Aerospace Engineering Nanjing University of Aeronautics Astronautics Nanjing China College of Mechanics Material Hohai University Nanjing China 《Acta Mechanica Sinica》2011,27(3):452-460
The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and reliable.During parameters’ iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element(FCSE) partial differentiation,which proves high computation effciency of the studied method. 相似文献
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根据LiouvillevonNeumann方程从理论上对特形脉冲做了全面的描述,提出了一种具体的调幅特形脉冲设计方案:首先将待设计的脉冲展成一个有限Fourier级数,然后根据Bloch方程的解析解准确计算出各阶正弦、余弦波的频谱,再将这些频谱组合后与该脉冲的理想频谱进行比较构成误差函数,最后运用鲍威尔-模拟退火组合优化算法计算出全局最优Fourier系数,即可得到所需脉冲的表达式.应用此设计方案,得到了体系处于热平衡态时的特形激励脉冲和反转脉冲的具体表达式.计算机模拟表明,所得脉冲的频谱具有较好的选择性
关键词:
核磁共振
特形脉冲
Bloch方程
鲍威尔模拟退火组合优化算法 相似文献