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Ground state energy of excitons in quantum dot treated variationally via Hylleraas-lik. wavefunction

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Chinese Physics B 2009年第4期18卷 1578-1585页

作者： S. Sak.roglu . Dogan A. Yιldιz k. akgngr H. Epik.Y. Ergn H. Sarι . Sk.en Physics Department Dokuz Eyll University Physics Department Anadolu University Physics Department Cumhuriyet University

In this work. the effects of quantum confinement on the ground state energy of a correlated electron-hole pair in a spherical and in a disc-lik. quantum dot have been investigated as a function of quantum dot size. Under parabolic confinement potential and within effective mass approximation ritz＇s variational method is applied to Hylleraas-lik. trial wavefunction. An efficient method for reducing the main effort of the calculation of terms lik. τek. exp （-λτeh） is introduced. The main contribution of the present work.is the introduction of integral transforms which provide the calculation of expectation value of energy and the related matrix elements to be done analytically over single-particle coordinates instead of Hvlleraas coordinates.

关键词： exciton parabolic confinement variational method Hylleraas coordinates

Ground state energy of He isoelectronic sequence treated variationally via Hylleraas-lik. wavefunction

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Chinese Physics B 2009年第6期18卷 2238-2243页

作者： Serpil Sak.roglu k.dir akgngr Ismail Sk.en Physics Department Dokuz Eyll University

In this study, the energy for the ground state of helium and a few helium-lik. ions （Z=1-6） is computed variationally by using a Hylleraas-lik. wavefunction. A four-parameters wavefunction, satisfying boundary conditions for coalescence points, is combined with a Hylleraas-lik. basis set which explicitly incorporates r12 interelectronic distance. The main contribution of this work.is the introduction of modified correlation terms leading to the definition of integral transforms which provide the calculation of expectation value of energy to be done analytically over single-particle coordinates instead of Hylleraas coordinates.

关键词： He isoelectronic sequence Hylleraas basis set electronic correlation variational method

Mitochondrial therapeutics and mitochondrial transfer for neurodegenerative diseases and aging

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Neural regeneration research 2025年第3期20卷 794-796页

作者： Neville ng Michelle Newbery Nicole Miles Lezanne Ooi Molecular Horizons and School of Chemistry and Molecular Bioscience University of WollongongWollongongNSWAustralia

Mitochondrial dysfunction and neurodegeneration:Progressive neurodegenerative diseases affect a significant proportion of the population;in a single year,there are as many as 276 million disabilities and 9 million dea... 详细信息

关键词： degenerative diseases Mitochondrial

robust interface and excellent as-built mechanical properties of Ti–6Al–4V fabricated through laser-aided additive manufacturing with powder and wire

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 154-168页

作者： Fei Weng Guijun Bi Youxiang Chew Shang Sui Chaolin Tan Zhenglin Du Jinlong Su Fern Lan ng k.y Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong Engineering&Technology Research Center for Superhard MaterialSchool of Materials Science and EngineeringShandong UniversityJinan 250061China Institute of Intelligent Manufacturing Guangdong Academy of SciencesGuangzhou 510095China Singapore Institute of Manufacturing Technology 5 Cleantech Loop636732Singapore

The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),*** the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire *** characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α *** mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and *** mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat *** fracture occurred within the interfacial area,further suggesting the robust *** findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.

关键词： laser-aided additive manufacturing powder deposition wire deposition interfacial characteristic mechanical behavior

Solving sparse non-negative tensor equations： algorithms and applications

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Frontiers of Mathematics in China 2015年第3期10卷 649-680页

作者： Xutao LI Michael k. ng School of Computer Engineering Nanyang Technological University Singapore 639798 Singapore Centre for Mathematical Imaging and Vision and Department of MathematicsHong Kong Baptist University Hong Kong China

We study iterative methods for solving a set of sparse non-negative tensor equations （multivariate polynomial systems） arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional network.. By mak.ng use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional network. are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.

关键词： Nonnegative tensor multi-dimensional network information retrieval community iterative method multivariate polynomial equation

Fourier transform technique in variational treatment of two-electron parabolic quantum dot

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Chinese Physics B 2009年第8期18卷 3508-3516页

作者： S.Sak.roglu A.Yιldιz .Dogan k.akgngr H.Epik.Y.Ergn H.Sarι .Sk.en Physics Department Dokuz Eyll University Physics Department Anadolu University Physics Department Cumhuriyet University

In this work. we propose an efficient method of reducing the computational effort of variational calculation with a Hylleraas-lik. trial wavefunction. The method consists of introducing integral transforms for the terms as r12^κ exp （-λτ12） which provide the calculation of the expectation value of energy and the relevant matrix elements to be done analytically over single-electron coordinates instead of Hylleraas coordinates. We have used this method to calculate the ground state energy of a two-electron system in a spherical dot and a disk.lik. quantum dot separately. Under parabolic confinement potential and within effective mass approximation size and shape effects of quantum dots on the ground state energy of two electrons have been investigated. The calculation shows that our results even with a small number of basis states are in good agreement with previous theoretical results.

关键词： two-electron quantum dot parabolic confinement variational method Hylleraas coor- dinates

Positron-Lithium Atom and Electron-Lithium Atom Scattering Systems at Intermediate and High Energies

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Chinese Physics Letters 2006年第7期23卷 1753-1756页

作者： k. ratnavelu S. Y. ng Institute of Mathematical Sciences Faculty of Science University of Malaya 50603 Kuala Lumpur Malaysia Department of Physics Faculty of Science National University of Singapore Singapore

The coupled-channel optical method is used to study positron scattering by atomic lithium at energies ranging from the ionization threshold to 60eV, The present method simultaneously treats the target channels and the positronium （Ps） channels in the coupled-channel method together with the continuum effects via an ab-initio optical potential. Ionization, elastic and inelastic cross sections in target channels, and the total cross section are also reported and compared with other theoretical and experimental data. A comparative study with the corresponding electron-lithium data is also reported.

关键词： CLOSE-COUPLIng THEOrY HYDrOGEN SCATTErIng CrOSS-SECTIONS COLLISIONS

Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

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China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem akgün Çağın Bolat Ali Gök.enli Faculty of Mechanical Engineering Istanbul Technical University34437İstanbulTurkey Faculty of Engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms mak.s it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and *** this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a *** to their features lik. low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors *** this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF ***,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive *** results show that PEC particles can be an alternative to expensive hollow spheres used in the previous ***,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

MODIFIED NEWTON＇S ALGOrITHM FOr COMPUTIng THE GrOUP INVErSES OF SIngULAr TOEPLITZ MATrICES

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Journal of Computational Mathematics 2006年第5期24卷 647-656页

作者： Jian-feng Cai Michael k. ng Yi-min Wei Department of Mathematics The Chinese University of Hong Kong Hong Kong Department of Mathematics Hong Kong Baptist University Hong Kong School of Mathematical Sciences Fudan University Shanghai 200433 China ~ Key Laboratory of Mathematics for Nonlinear Sciences (Fudan University) Ministry of Education

Newton＇s iteration is modified for the computation of the group inverses of singular Toeplitz matrices. At each iteration, the iteration matrix is approximated by a matrix with a low displacement rank. Because of the displacement structure of the iteration matrix, the matrix-vector multiplication involved in Newton＇s iteration can be done efficiently. We show that the convergence of the modified Newton iteration is still very fast. Numerical results are presented to demonstrate the fast convergence of the proposed method.

关键词： Newton's iteration Group inverse Toeplitz matrix Displacement rank.