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Manifold Construction Over Polyhedral Mesh

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Communications in Mathematics and Statistics 2017年第3期5卷 317-333页

作者： Chun Zhang ligang liu School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026People’s Republic of China

We present a smooth parametric surface construction method over polyhe-dral mesh with arbitrary topology based on manifold construction *** surface is automatically generated with any required smoothness,and it has an explicit *** prior methods that build manifolds from meshes need some preprocess to get poly-hedral meshes with specialtypes of connectivity,such as quad mesh and triangle mesh,the preprocess will result in more *** a skillful use of a kind of bivariate spline function which defines on arbitrary shape of 2D polygon,we introduce an approach that directly works on the input mesh without such ***-closedpolyhe-dral mesh,we apply a global parameterization and directly divide it into several *** for closed polyhedral mesh,we propose to segment the mesh into a sequence of quadrilateral patches without any *** each patch is an non-closed polyhedral mesh,the non-closed surface construction method can be *** all the patches are smoothly stitched with a special process on the boundary charts which define on the boundary vertex of each ***,the final constructed surface can also achieve any required smoothness.

关键词： Manifold construction Smoothness Polyhedral mesh Arbitrary connectivity

Head Curvature of Pure Titanium Sheet Influenced by Process Parameters and Controlling in Hot Rolling Process

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Journal of Wuhan University of Technology(Materials Science) 2017年第2期32卷 444-450页

作者：于辉 LI Jun liu ligang 肖宏 College of Mechanical Engineering Yanshan University Qinhuangdao 066004 China National Engineering Research Center for Equipment and Technology of Cold Steel Rolling Yanshan University Qinhuangdao 066004 China State Key Laboratory for Comprehensive Utilization of Vanadium and Titanium Resources Ansteel Research Institute of Vanadium & Titanium (1ran&steel) Panzhihua 617000 China

We investigated the influences of process parameters on the head curvature of pure titanium sheet in hot rolling process and proposed the controlling means. First, the thermal simulation experiments for pure titanium TA1 were carried out to investigate the hot deformation behaviors of pure titanium in the temperature range of 700-800 ℃ with strain rate range of 1-20 S-1, and the processing map was established to determine optimized deformation parameters. Then, the finite element model has been constructed and used to analyze the effect of process parameters on the direction and severity of head curvature of pure titanium sheet. The process parameters considered in the present study include workpiece temperature, work roll diameter, pass reduction, oxide scale thickness of workpiece surface, and interface friction coefficient. The simulation results show that the workpiece temperature and the interface friction coefficient are the two main factors. The proposed controlling means was carried out on a hot rolling production line and solved the head curvature problem effectively. The rolling practices indicate that the rolling yield is improved greatly.

关键词： head curvature hot rolling process parameter thermal simulation pure titanium sheet

Impact of the Global Financial Crisis on China: Empirical Evidence and Policy Implications

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China & World Economy 2009年第6期17卷 1-23页

作者： ligang liu Head of China Economic Research Australia and New Zealand Banking Group Hong Kong

This paper applies a structural vector autoregression analysis to quantify the impact of the global financial crisis on China. It is found that the impact is indeed sizeable： a 1-percent decline in economic growth in the USA, the EU and Japan is likely to lead to a0. 73-percent decline in growth in China. The article discusses whether the current measures of fiscal stimulus are adequate to offset the sharp decline in external demand Although there is little doubt that the massive fiscal stimulus will largely offset the significant shortfalls in external demand, the current growth pattern in China will be increasingly unsustainable in the long term. China ＂s reform cycles suggest that external shocks are often opportunities for structural reforms. Therefore, the crisis could also be a catulyst for rebalancing China ＇s economic structure so as to return the economy to a sustainable path.

关键词： China global financial crisis structural vector autoregression analysis

Fluidization of non-spherical particles:Sphericity,Zingg factor and other fluidization parameters

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Particuology 2008年第2期6卷 125-129页

作者： Baiqian liu Xiaohui Zhang ligang Wang Hui Hong School of Mechanical Engineering University of Science and Technology Beijing Beijing 100083 China

A comparison of sphericity and Zingg factor for particle morphology and description of fluidized-bed dynamics are presented. It is found that Zingg factor Fz = LH/B2 （where L, H and B are, respectively, the length, breadth and height of a particle） well describes the effect of particle morphology. Experimental results show that non-spherical particles give poor fluidizing quality as compared to spherical particles in terms of pressure drop, Umf, etc. With the same volume-equivalent diameter, non-spherical particles have lower Umf and fluidizing coefficient 8. Some smooth curves have been obtained between the parameters 8, Umf and Fz. The quality of fluidization could be evaluated by fluidizing coefficient, which has been correlated to the Zingg factor and minimum fluidizing velocity in this paper.

关键词： Particle morphology Fluidized-bed Sphericity Non-spherical particle

A Revisit of Shape Editing Techniques:From the Geometric to the Neural Viewpoint

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Journal of Computer Science & Technology 2021年第3期36卷 520-554页

作者： Yu-Jie Yuan Yu-Kun Lai Tong Wu Lin Gao ligang liu Beijing Key Laboratory of Mobile Computing and Pervasive Device Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China School of Computer Science and Informatics Cardiff UniversityCardiff CF243AAU.K. School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China

3D shape editing is widely used in a range of applications such as movie production,computer games and computer aided *** is also a popular research topic in computer graphics and computer *** past decades,researchers have developed a series of editing methods to make the editing process faster,more robust,and more ***,the deformed shape is determined by the optimal transformation and weights for an energy *** increasing availability of 3D shapes on the Internet,data-driven methods were proposed to improve the editing *** recently as the deep neural networks became popular,many deep learning based editing methods have been developed in this field,which are naturally *** mainly survey recent research studies from the geometric viewpoint to those emerging neural deformation techniques and categorize them into organic shape editing methods and man-made model editing *** traditional methods and recent neural network based methods are reviewed.

关键词： mesh deformation man-made model editing deformation representation optimization deep learning

Parametric curve with an implicit domain

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Science China Mathematics 2014年第12期57卷 2621-2634页

作者： ZHANG WeiHong DENG JianSong YANG ZhouWang liu ligang School of Mathematical Sciences University of Science and Technology of China School of Mathematics and Statistics Hefei Normal University

In this paper we present a new representation of curve, named parametric curve with an implicit domain(PCID), which is a curve that exists in parametric form defined on an implicit domain. PCID provides a bridge between parametric curve and implicit curve because the conversion of parametric form or implicit form to PCID is very convenient and efficient. We propose a framework model for mapping given points to the implicit curve in a homeomorphic manner. The resulting map is continuous and does not overlap. This framework can be used for many applications such as compatible triangulation, image deformation and fisheye views. We also present some examples and experimental results to demonstrate the effectiveness of the framework of our proposed model.

关键词： parametric curve with an implicit domain regularity quadratic programming image deformation

Practical construction of globally injective parameterizations with positional constraints

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Computational Visual Media 2023年第2期9卷 265-277页

作者： Qi Wang Wen-Xiang Zhang Yuan-Yuan Cheng ligang liu Xiao-Ming Fu School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China

We propose a novel method to compute globally injective parameterizations with arbitrary positional constraints on disk topology *** to this method is the use of a scaffold mesh that reduces the globally injective constraint to a locally flipfree ***,given an initial parameterized mesh containing flipped triangles and satisfying the positional constraints,we only need to remove the flips of a overall mesh consisting of the parameterized mesh and the scaffold mesh while always meeting positional *** successfully apply this idea,we develop two key ***,an initialization method is used to generate a valid scaffold mesh and mitigate difficulties in eliminating ***,edgebased remeshing is used to optimize the regularity of the scaffold mesh containing flips,thereby improving practical *** to state-of-the-art methods,our method is much more *** demonstrate the capability and feasibility of our method on a large number of complex meshes.

关键词： globally injective parameterization constrained parameterization bijection flip-free scaffold mesh

The Effect of Digital Transformation and Supply Chain Integration on Enterprise Performance:The Moderating Role of Entrepreneurship

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Frontiers of Business Research in China 2022年第4期16卷 412-438页

作者： LI Qi liu ligang SHAO Jianbing Business School Liaoning UniversityShenyang 110036China

Digital transformation provides companies with a productive approach to transforming and upgrading enterprise resources and capabilities and to exploiting external subject forces to unleash and magnify their potential,thus advancing high-quality enterprise ***,using regression analysis of the data of China’s non-financial listed firms from 2007‒2019 obtained by Python,this paper finds that digital transformation has enormously improved enterprise ***,digital transformation has powerfully boosted supply chain integration,which has played a mediation role in the impact of digital transformation on enterprise ***,entrepreneurship plays a positive moderating effect on enterprise performance through supply chain integration during digital *** further heterogeneity analysis finds that digital transformation performs better in large,public,state-owned,mature,and non-manufacturing(service industry)***,the positive effect of digital transformation on enterprise performance and supply chain integration is not significant in small and medium-sized ***,supply chain integration cannot play a mediating role in the impact of digital transformation of manufacturing enterprises upon their *** paper probes the realization mechanism and micro-foundation of digital transformation,and its conclusion contributes to high-quality digital transformation.

关键词： digital transformation supply chain integration entrepreneurship enterprise performance

Survey on computational 3D visual optical art design

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Visual Computing for Industry,Biomedicine,and Art 2022年第1期5卷 378-408页

作者： Kang Wu Xiao‑Ming Fu Renjie Chen ligang liu School of Mathematics University of Science and Technology of ChinaHefei 230026China

Visual arts refer to art experienced primarily through vision.3D visual optical art is one of *** use their rich imagination and experience to combine light and objects to give viewers an unforgettable visual ***-ever,the design process involves much trial and error;therefore,it is often very *** has prompted many researchers to focus on proposing various algorithms to simplify the complicated design processes and help artists quickly realize the arts in their *** help computer graphics researchers interested in creating 3D visual optical art,we first classify and review relevant studies,then extract a general framework for solving 3D visual optical art design problems,and finally propose possible directions for future research.

关键词： Computational art 3D visual art Automatic art design Optical art