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Numerical simulation of square shaped particle sedimentation

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Particuology 2024年第1期84卷 107-116页

作者： Govind Sharma Bahni Ray department of Mechanical Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi110016India

Direct numerical simulations of square particle sedimentation in a viscous incompressible fluid are presented to examine the effects of sharp edges for various particle-to-fluid density ratios and different initial inclination *** settling process exhibits four different motion regimes;non-oscillatory,non-uniform centered oscillatory,uniform off-centered oscillatory,and non-uniform off-centered(irregular)*** moderate density ratios,we observe that the rotational motion of settling square particle varies with the initial inclination *** employ Dynamic Time Warping and Fast Fourier Transform to analyze translational and angular *** systems are described using phase-space plots,and a chaotic phenomenon is observed at a higher density ratio.

关键词： Sedimentation Distributed Lagrangian multiplier Phase synchronization Oscillations

Enhancing fatigue performance of AZ31 magnesium alloy components fabricated by cold metal transfer-based wire arc directed energy deposition through LPB

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Journal of Magnesium and Alloys 2024年第4期12卷 1638-1662页

作者： Shambhu Kumar Manjhi Srikanth Bontha A.S.S.Balan department of Mechanical Engineering National Institute of Technology KarnatakaSurathkalSrinivasanagarMangaloreKarnataka 575025India

Cold Metal Transfer-Based Wire Arc Directed Energy Deposition(CMT-WA-DED)presents a promising avenue for the rapid fabrication of components crucial to automotive,shipbuilding,and aerospace ***,the susceptibility to fatigue of CMT-WA-DED-produced AZ31 Mg alloy components has impeded their widespread adoption for critical load-bearing *** this study,a comprehensive investigation into the fatigue behaviour of WA-DED-fabricated AZ31 Mg alloy has been carried out and compared to commercially available wrought AZ31 *** findings indicate that the as-deposited parts exhibit a lower fatigue life than wrought Mg alloy,primarily due to poor surface finish,tensile residual stress,porosity,and coarse grain microstructure inherent in the WA-DED *** Plasticity Burnishing(LPB)treatment is applied to mitigate these issues,which induce significant plastic deformation on the *** treatment resulted in a remarkable improvement of fatigue life by 42%,accompanied by a reduction in surface roughness,grain refinement and enhancement of compressive residual stress ***,during cyclic deformation,WA-DED specimens exhibited higher plasticity and dislocation density compared to both wrought and WA-DED+LPB specimens.A higher fraction of Low Angle Grain Boundaries(LAGBs)in WA-DED specimens contributed to multiple crack initiation sites and convoluted crack paths,ultimately leading to premature *** contrast,wrought and WA-DED+LPB specimens displayed a higher percentage of High Angle Grain Boundaries(HAGBs),which hindered dislocation movement and resulted in fewer crack initiation sites and less complex crack paths,thereby extending fatigue *** findings underscore the effectiveness of LPB as a post-processing technique to enhance the fatigue performance of WA-DED-fabricated AZ31 Mg alloy *** study highlights the importance of LPB surface treatment on AZ31 Mg components produced by CMT-WA-DED to remove surface d

关键词： Wire arc additive manufacturing AZ31 Mg alloy Low plasticity burnishing Low cycle fatigue test Strain amplitude

Functional inequalities on manifolds with non-convex boundary

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Science China mathematics 2018年第8期61卷 1421-1436页

作者： Lijuan Cheng Anton Thalmaier James Thompson mathematics Research Unit University of Luxembourg department of Applied mathematics Zhejiang University of Technology

In this article, new curvature conditions are introduced to establish functional inequalities including gradient estimates, Harnack inequalities and transportation-cost inequalities on manifolds with non-convex boundary.

关键词： Ricci curvature gradient inequality log-Sobolev inequality geometric flow

Fidelity of states in infinite-dimensional quantum systems

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1820-1827页

作者： HOU JinChuan QI XiaoFei department of mathematics Taiyuan University of TechnologyTaiyuan 030024China department of mathematics Shanxi UniversityTaiyuan 030006China

We discuss the fidelity of states in the infinite-dimensional systems and give an elementary proof of the infinite-dimensional version of Uhlmann's *** theorem is used to generalize several properties of the fidelity of the finite-dimensional case to the infinite-dimensional *** are somewhat different from those for the finite-dimensional case.

关键词： Hilbert space trace quantum states fidelity entanglement fidelity

MULTIPLE SYMMETRIC RESULTS FOR A CLASS OF BIHARMONIC ELLIPTIC SYSTEMS WITH CRITICAL HOMOGENEOUS NONLINEARITY IN R^N

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Acta Mathematica Scientia 2017年第6期37卷 1665-1684页

作者：邓志颖黄毅生 School of mathematics and Physics Chongqing University of Posts and Telecommunications department of mathematics Soochow University

This paper is dedicated to studying the existence and multiplicity of symmetric solutions for a class of biharmonic elliptic systems with critical homogeneous nonlinearity in RN. By virtue of variational methods and the symmetric criticality principle of Palais, we establish several existence and multiplicity results of G-symmetric solutions under certain appropriate hypotheses on the parameters and the weighted functions.

关键词： G-symmetric solution symmetric criticality principle critical Sobolev expo-nent biharmonic elliptic systems

Matrix transformations of l^q(X) to l^p(Y )

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Applied mathematics(A Journal of Chinese Universities) 2012年第1期27卷 78-86页

作者： GUO Hao LI Rong-lu WU Jun-de department of mathematics Harbin Institute of TechnologyHarbin 150001China department of mathematics Zhejiang UniversityHangzhou 310027China

Let X and Y be Banach spaces, 0 〈 q 〈＋∞, i ≤ p 〈＋∞. In this paper, we characterize matrix transformations of lq （ X ） to lp （ Y ）.

关键词： matrix transformation, sequence space demi-linear mapping.

Peristaltic flow of Sisko fluid in a uniform inclined tube

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Acta Mechanica Sinica 2010年第5期26卷 675-683页

作者： Sohail Nadeem Noreen Sher Akbar department of mathematics Quaid-i-Azam University 45320

We have analyzed an incompressible Sisko fluid through an axisymmetric uniform tube with a sinusoidal wave propagating down its walls. The present analysis of non- Newtonian fluid is investigated under the considerations of long wavelength and low Reynolds number approximation. The analytic solution is obtained using （i） the regular perturbation method （ii） the Homotopy analysis method （HAM）. The comparison of both the solutions is presented graphically. The results for the pressure rise, frictional force and pressure gradient have been calculated numerically and the results are studied for various values of the physical parameters of interest, such as α （angle of inclination）, b^＊（Sisko fluid parameter）, Ф （amplitude ratio） and n （power law index）. Trapping phenomena is discussed at the end of the article.

关键词： Peristaltic flow Sisko fluid Perturbation method Homotopy analysis method

COMPLEX SYSTEM ANALYSIS OF MARKET RETURN PERCOLATION MODEL ON SIERPINSKI CARPET LATTICE FRACTAL

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Journal of Systems Science & Complexity 2014年第4期27卷 743-759页

作者： DONG Yanfang WANG Jun department of mathematics College of ScienceBeijing Jiaotong University

This paper investigates the statistical behaviors of fluctuations of price changes in a stock *** Sierpinski carpet lattice fractal and the percolation system are applied to develop a new random stock price for the financial *** Sierpinski carpet is an infinitely ramified fractal and the percolation theory is usually used to describe the behavior of connected clusters in a random *** authors investigate and analyze the statistical behaviors of returns of the price model by some analysis methods,including multifractal analysis,autocorrelation analysis,scaled return interval ***,the authors consider the daily returns of Shanghai Stock Exchange Composite Index,and the comparisons of return behaviors between the actual data and the simulation data are exhibited.

关键词： Percolation return Sierpinski carpet lattice fractal statistical analysis stock market.

Analytic solution for magnetohydrodynamic boundary layer flow of Casson fluid over a stretching/shrinking sheet with wall mass transfer

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Chinese Physics B 2013年第2期22卷 314-319页

作者： Krishnendu Bhattacharyya Tasawar Hayat Ahmed Alsaedi department of mathematics The University of BurdwanBurdwan-713104West BengalIndia department of mathematics Quaid-I-Azam University 45320Islamabad 44000Pakistan department of mathematics Faculty of ScienceKing Abdulaziz UniversityJeddah 21589Saudi Arabia

In this analysis,the magnetohydrodynamic boundary layer flow of Casson fluid over a permeable stretching/shrinking sheet in the presence of wall mass transfer is *** similarity transformations,the governing equations are converted to an ordinary differential equation and then solved *** introduction of a magnetic field changes the behavior of the entire flow dynamics in the shrinking sheet case and also has a major impact in the stretching sheet *** similarity solution is always unique in the stretching case,and in the shrinking case the solution shows dual nature for certain values of the *** stronger magnetic field,the similarity solution for the shrinking sheet case becomes unique.

关键词： magnetohydrodynamic boundary layer Casson fluid stretching/shrinking sheet wall mass transfer analytic solution