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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

维普期刊数据库

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

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

Calibration of the Solar X-ray Detector on-board the Macao Science Satellite-1B for Soft X-ray Detection

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Science China Earth Sciences 2025年第1期68卷 11-26页

作者： Man-Hei ng Xiaoping ZHAng Jianwu CHEN Yongqiang SHI Fuchang ZUO Wenxi PEng Weichun FU Liansheng LI Pengwei LUO Chi-Long TAng Guozheng ZHAng Zhiwu MEI Li WAng Cunhui LI Jiaming OU Yanyan XU State k.y Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology China National Space Administration (CNSA) Macau Center for Space Exploration and Science Space Optoelectronic Measurement and Perception Laboratory Beijing Institute of Control Engineering Institute of High Energy Physics Chinese Academy of Sciences Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of Physics

The Solar X-ray Detector(SXD) on-board the Macao Science Satellite-1B(MSS-1B) was successfully launched via the Chinese Long March-2C rock.t on 21 May 2023, and commenced operations in early June of the same year. The MSS-1B/Soft X-ray Detection Units(SXDUs) employ two silicon drift detectors(SDDs), providing a wide range of energy spectra spanning from 0.7 to 24 k.V. Notably, the SXDUs deliver a high-resolution capability of 0.14 k.V@5.9 k.V and operate with a time cadence of 1 second. Here, we perform thorough calibrations of the MSS-1B/SXDUs, employing a combination of ground experiments and simulations. In addition, quantitative analysis comparing the flux measurements obtained by the MSS-1B/SXDUs to the data collected by the Geostationary Operational Environmental Satellite(GOES), provides compelling evidence of their consistency. Furthermore, the preliminary spectral analysis results showcase the robustness and expected performance of the MSS-1B/SXDUs, unlock.ng their potential for facilitating the study of dynamic evolution of solar flares. Moreover, the innovative MSS-1B/Solar X-ray Detector facilitates concurrent observations of solar soft and hard X-rays, thereby mak.ng valuable contributions to the advancements in solar research.

关键词： Macao Science Satellite-1B (MSS-1B) Calibration Solar X-Ray Detector Spectrometer Soft X-rays Solar flares Solar abundances

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.

Ending as Beginning： Chinese Translations of Edward Bellamy＇s Utopian Novel Look.ng Back.ard： 2000-1887

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Frontiers of Literary Studies in China-Selected Publications from Chinese Universities 2016年第1期10卷 9-35页

作者： k.nny k. k. ng Department of Chinese and History The City University of Hong Kong Tat Chee Avenue Kowloon Hong Kong China

The Chinese translation of Edward Bellamy＇s Look.ng Back.ard.. 2000-1887（1887） at the turn of the twentieth century has been little studied, in spite of Bellamy＇s obvious influence on Chinese intellectuals and reformist think.rs Enthusiastically embraced by the intelligentsia as a gospel of social change, the utopian fiction has inspired subsequent Chinese writings of science fantasy in popular fiction. Bellamy＇s tale centers on the adventure of time-traveler Julian West, a young Bostonian who is put into a hypnotic sleep in the late nineteenth century and awak.ns in the year 2000 in a socialist utopia. He discovers an ideally realized vision of the future, one unthink.ble in his own century. This article argues that Chinese translators, in their conventional form of storytelling, have intentionally converted Bellamy＇s original religious prophesy into a vision of a new and modernized state that is in line with the Chinese evolutionary historical imagination. It discusses the problematic of imagining the future by delineating the relationships of utopianism, social modernity, and temporality as the novel was written by an engaged American writer and then rendered into various Chinese versions by Western missionaries, Chinese intellectuals, and popular writers.

关键词： apocalyptic fiction dream Edward Bellamy Evolutionism fantastic,futuristic world translation utopia

BLOCk.TRIAngULAR PRECONDITIONERS FOR SYSTEMS ARISIng FROM EDGE-PRESERVIng IMAGE RESTORATION

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Journal of Computational Mathematics 2010年第6期28卷 848-863页

作者： Zhong-Zhi Bai Yu-Mei Huang Michael k. ng LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of Mathematics and Statistics Lanzhou University Lanzhou 730000 China Department of Mathematics Hong Kong Baptist University Kowloon Tong Hong Kong

Signal and image restoration problems are often solved by minimizing a cost function consisting of an l2 data-fidelity term and a regularization term. We consider a class of convex and edge-preserving regularization functions. In specific, half-quadratic regularization as a fixed-point iteration method is usually employed to solve this problem. The main aim of this paper is to solve the above-described signal and image restoration problems with the half-quadratic regularization technique by mak.ng use of the Newton method. At each iteration of the Newton method, the Newton equation is a structured system of linear equations of a symmetric positive definite coefficient matrix, and may be efficiently solved by the preconditioned conjugate gradient method accelerated with the modified block.SSOR preconditioner. Our experimental results show that the modified block.SSOR preconditioned conjugate gradient method is feasible and effective for further improving the numerical performance of the half-quadratic regularization approach.

关键词： Block.system of equations Matrix preconditioner Edge-preserving Image restoration Half-quadratic regularization.

维普期刊数据库

Development of an industrial Internet of things suite for smart factory towards re-industrialization

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Advances in Manufacturing 2017年第4期5卷 335-343页

作者： C. k. M. Lee S. Z. Zhang k. k. H. ng Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hong Kong People's Republic of China Department of Information Management Zhejiang University of Finance and Economics Hangzhou 310018Zhejiang People's Republic of China

Re-industrialization, which supports industrial upgrading and transformation, promotes smart production and high value-added manufacturing processes, and helps to create new momentum for the economic. Under the current situation, industrialists encounter several chal- lenges to achieve re-industrialization. Firstly, the cost and technical thresholds for industrialists to leverage emerging technologies are high. Secondly, there are huge quantities and numerous types of Internet of things （IoT） devices in smart factories, warehouses and offices. The enormous extents of data exchange and communication, manage- ment, monitoring and control of IoT devices as well as the establishment and maintenance of a reliable cloud platform hinder industrialists to implement an integrated smart production management. Therefore, to achieve re-indus- trialization, an industrial Internet of things （IIoT） suite consisting of a micro-services-based IIoT cloud platform and IIoT-based smart hub is proposed, which helps to materialize re-industrialization and to conduct industrial upgrading and transformation to achieve smart production and high value-added manufacturing processes.

关键词： Industrial Intemet of things (IIoTs) Cloudplatform Micro-services-based Industry 4.0 Reindustrialization

EFFICIENT BOX-CONSTRAINED TV-TYPE-l^1 ALGORITHMS FOR RESTORIng IMAGES WITH IMPULSE NOISE

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Journal of Computational Mathematics 2013年第3期31卷 249-270页

作者： Liyan Ma Michael k. ng Jian Yu Tieyong Zeng School of Computer and Information Technology Beijing Jiaotong University Beijing 100044 China Department of Mathematics Hong Kong Baptist University Hong Kong China

In this paper, we study the restoration of images simultaneously corrupted by blur and impulse noise via variational approach with a box constraint on the pixel values of an image. In the literature, the TV-l^1 variational model which contains a total variation （TV） regularization term and an l^1 data-fidelity term, has been proposed and developed. Several numerical methods have been studied and experimental results have shown that these methods lead to very promising results. However, these numerical methods are designed based on approximation or penalty approaches, and do not consider the box constraint. The addition of the box constraint mak.s the problem more difficult to handle. The main contribution of this paper is to develop numerical algorithms based on the derivation of exact total variation and the use of proximal operators. Both one-phase and two-phase methods are considered, and both TV and nonlocal TV versions are designed. The box constraint [0, 1] on the pixel values of an image can be efficiently handled by the proposed algorithms. The numerical experiments demonstrate that the proposed methods are efficient in computational time and effective in restoring images with impulse noise.

关键词： Image restoration Impulse noise Total variation Nonlocal total variation Proximal Operators.