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Multiquadric Finite Difference (MQ-FD) Method and its Application

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Advances in Applied Mathematics and Mechanics 2009年第5期1卷 615-638页

作者： yong Yuan Shan chang Shu Ning Qin Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore 119260Singapore Department of Mechanical Engineering University of SheffieldMappin StreetSheffield S13JDUnited Kingdom

The conventional finite difference(FD)schemes are based on the low order polynomial approximation in a local *** paper shows that when the polynomial approximation is replaced by the multiquadric(MQ)function approximation in the same region,a new FD method,which is termed as MQ-FD method in this work,can be *** paper gives analytical formulas of the MQ-FD method and carries out a performance study for its derivative approximation and solution of Poisson equation and the incompressible Navier-Stokes *** addition,the effect of the shape parameter c in MQ on the formulas of the MQFD method is *** approximation in one-dimensional space and Poisson equation in two-dimensional space are taken as model problems to study the accuracy of the MQ-FD ***,a lid-driven flow problem in a square cavity is simulated by the MQ-FD *** obtained results indicate that this method may solve the engineering problem very accurately with a proper choice of the shape parameter c.

关键词： MQ-FD method shape parameter central FD method

Therapeutic advances: Single incision laparoscopic hepatopancreatobiliary surgery

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World journal of Gastroenterology 2014年第39期20卷 14329-14337页

作者： Stephen Kin yong chang Kai Yin Lee Division of Hepatobiliary and Pancreas Surgery Department of Surgery National University Singapore Hospital

Single-port laparoscopic surgery(SPLS) is proposed to be a step towards minimizing the invasiveness of surgery, and has since gained popularity in several surgical sub-specialties including hepatopancreatobiliary surgery. SPLS has since been applied to cholecystectomy, liver resection as well as pancreatectomy for a multitude of pathologies. Benefits of SPLS over conventional multi-incision laparoscopic surgery include improved cosmesis and potentially post-operative pain at specific time periods and extra-umbilical sites. However, it is also associated with longer operating time, increased rate of complications, and increased rate of port-site hernia. There is no significant difference between length of hospital stay. SPLS has a significant learning curve that affects operating time, rate of conversion and rate of complications. In this article, we review the literature on SPLS in hepatobiliary surgery- cholecystectomy, hepatectomy and pancreatectomy, and offer tips on overcoming potential technical obstacles and minimizing the complications when performing SPLS- surgeon position, position of port and instruments, instrument crossing position, standard hand grip vs reverse hand grip, snooker cue guide position, prevention of incisional hernia. SPLS is a promising direction in laparoscopic surgery, and we recommend step-wise progression of applications of SPLS to various hepatopancreatobiliary surgeries to ensure safe adoption of the surgical technique.

关键词： Single port laparoscopic Cholecystectomy Hepatectomy Pancreatectomy Liver resection

Mold breakout prediction based on computer vision and machine learning

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journal of Iron and Steel Research International 2024年第8期31卷 1947-1959页

作者： Yan-yu Wang Qi-can Wang yong-chang Zhang yong-hui Cheng Man Yao Xu-dong Wang School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina Key Laboratory of Solidification Control and Digital Preparation Technology Dalian University of TechnologyDalian 116024LiaoningChina

Breakout is the most serious production accident in continuous casting and must be detected and predicted by stable and reliable *** sticking region,which forms on the local copper plate and expanded into a"V"shape,is the typical precursor of ***,computer vision technology was exploited to visualize the temperature change rate of the copper plate based on the temperature signals from thermocouples;then,the static and dynamic features of the abnormal sticking region were ***,logistic regression and Adaboost models were used to study and identify these features,resulting in the development of a mold breakout prediction model based on computer vision and machine *** test results demonstrate that the proposed model can effectively distinguish anomalous temperature patterns and considerably reduce false alarms without any missing *** a result,the proposed method could offer valuable insights into the realm of abnormality detection and prediction during continuous casting process.

关键词： Abnormality detection Image processing Adaboost Logistic regression Continuous casting

Lattice Boltzmann and Finite Volume Simulation of Inviscid Compressible Flows with Curved Boundary

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Advances in Applied Mathematics and Mechanics 2010年第5期2卷 573-586页

作者： Kun Qu chang Shu yong Tian Chew Department of Mechanical Engineering National University of Singapore10 Kent Ridge CrescentSingapore119260

A 2D lattice Boltzmann model for inviscid compressible flows was proposed in this *** volume method was implemented on 2D curvilinear structural grids to solve the lattice BGK-Boltzmann *** scheme was used to perform ... 详细信息

关键词： Lattice Boltzmann method compressible flow finite volume method structural grids

Halogen bonding in the co-crystallization of potentially ditopic diiodotetrafluorobenzene:a powerful tool for constructing multicomponent supramolecular assemblies

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National Science Review 2020年第12期7卷 1906-1932页

作者： Xue-Hua Ding yong-Zheng chang chang-Jin Ou Jin-Yi Lin Ling-Hai Xie Wei Huang Key Laboratory of Flexible Electronics(KLOFE) & Institute of Advanced Materials(IAM) Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University(Nanjing Tech) Key Laboratory for Organic Electronics &Information Displays(KLOEID) and Institute of Advanced Materials (IAM) Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM)Nanjing University of Posts & Telecommunications(NUPT) Shaanxi Institute of Flexible Electronics(SIFE) Northwestern Polytechnical University (NPU)

Halogen bonding is emerging as a significant driving force for supramolecular self-assembly and has aroused great interest during the last two *** the various halogen-bonding donors,we take notice of the ability of 1,4-diiodotetrafluorobenzene(1,4-DITFB) to co-crystallize with diverse halogen-bonding acceptors in the range from neutral Lewis bases(nitrogen-containing compounds,N-oxides,chalcogenides,aromatic hydrocarbons and organometallic complexes) to anions(halide ions,thio/selenocyanate ions and tetrahedral oxyanions),leading to a great variety of supramolecular architectures such as discrete assemblies,1 D infinite chains and 2 D/3 D *** of them act as promising functional materials(***,phosphorescence,optical waveguide,laser,non-linear optics,dielectric and magnetism)and soft materials(*** crystal and supramolecular gel).Here we focus on the supramolecular structures of multicomponent complexes and their related physicochemical properties,highlight representative examples and show clearly the main directions that remain to be developed and improved in this *** the point of view of crystal engineering and supramolecular chemistry,the complexes summarized here should give helpful information for further design and investigation of the elusive category of halogen-bonding supramolecular functional materials.

关键词： halogen bond co-crystal physicochemical properties supramolecular chemistry crystal engineering

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轮轨摩擦自激振动有限元模型的模型优化研究

润滑与密封 2025年第1期50卷 105-110页

作者：张峻才陈光雄常勇唐宇刘崧楠华浩西南交通大学摩擦学研究所四川成都610031

目前在进行轮轨间摩擦自激振动分析时,大多选择用轮对-直线轨道摩擦自激振动有限元模型来模拟车辆在曲线上的运行状态,而基于轮对-曲线轨道摩擦自激振动有限元模型的仿真计算较少。基于轮轨间摩擦自激振动导致钢轨波磨的理论,研究了频... 详细信息

目前在进行轮轨间摩擦自激振动分析时,大多选择用轮对-直线轨道摩擦自激振动有限元模型来模拟车辆在曲线上的运行状态,而基于轮对-曲线轨道摩擦自激振动有限元模型的仿真计算较少。基于轮轨间摩擦自激振动导致钢轨波磨的理论,研究了频繁出现在地铁小半径曲线轨道上的波磨现象。使用有限元软件ABAQUS,分别建立轮对-直线轨道与轮对-曲线轨道摩擦自激振动有限元模型,采用复特征值分析法对比2种模型所预测的不稳定振动频率,并研究轨下垫板弹性模量和轮轨摩擦因数对钢轨波磨的影响。结果发现,轮对-曲线轨道模型更容易反映出轮轨接触时所产生的不稳定振动,且在低频方面有更好的表现结果;增大轮轨摩擦因数和轨下垫板弹性模量会导致等效阻尼比绝对值增大,导致钢轨波磨更容易发生。

关键词：钢轨波磨自激振动曲线轨道等效阻尼比振动频率

Early Cretaceous transpressional and transtensional tectonics straddling the Sulu orogenic belt,East China

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Geoscience Frontiers 2019年第6期10卷 2287-2300页

作者： Jun Wang Su-Chin chang yong Chen Shiyong Yan School of Resource Environment and Earth Sciences Yunnan UniversityKunming 650500China Department of Earth Sciences The University of Hong KongHong KongChina School of Geosciences China University of Petroleum(East China)Qingdao 266580China

The Sulu orogenic belt(SOB)separates the North and South China blocks in East Asia and formed during Triassic continent-continent ***,late Mesozoic post-collisional exhumation is poorly understood due to lack of surface evidence for Paleo-Pacific subduction and associated *** paper interprets the tectonic history of the SOB using detrital zircon age data from Early Cretaceous sedimentary units along with previously published geochronologic and geochemical data to reconstruct sedimentological and tectonic *** zircon age distributions obtained from sedimentary units include a 2.0 Ga subpopulation that appears only in turbidite units to the *** sediment probably derived from the Yangtze *** facies from the Jiao-Lai basin to the northwest appear to derive from the North China *** and geochemical data indicate that Early Cretaceous,post-collisional volcanism was compositionally bimodal(mafic-felsic)with associated intrusive activity that peaked at 120 *** images of northerly regions of the study area indicate this occurred in an extensional *** facies and field structural analyses revealed an unconformity interpreted to reflect rapid uplift with NW SE compression to the *** observed sinistral movement along the Tan-Lu fault,we interpret northwest and southeast regions of the SOB as experiencing transtensional and transpressional tectonics,respectively,driven by continuous subduction of the Paleo-Pacific *** of the Late Yanshannian granitoids marked the final formational stage of this unique tectonic setting.

关键词： Detrital zircon Seismic reflection Structural analysis Tectonic evolution Early Cretaceous

A Class of Rumor Spreading Models with Population Dynamics

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Communications in Theoretical Physics 2018年第12期69卷 795-802页

作者： Suyalatu Dong yong-chang Huang College of Applied Sciences Beijing University of Technology

Based on the characteristics of rumor spreading in online social networks, this paper proposes a new rumor spreading model. This is an improved SIS rumor spreading model in online social networks that combines the transmission dynamics and population dynamics with consideration of the impact of both of the changing number of online social network users and different levels of user activity. We numerically simulate the rumor spreading process. The results of numerical simulation show that the improved SIS model can successfully characterize the rumor spreading behavior in online social networks. We also give the effective strategies of curbing the rumor spreading in online social networks.

关键词： online social networks rumor spreading model population dynamics stability of equilibriumpoint

Two-Photon Jaynes-Cummings Model Governed by Milburn Equation with Phase Damping

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Communications in Theoretical Physics 2006年第4期45卷 702-708页

作者： CHEN chang-yong LI Shao-Hua LIU Zong-Liang Department of Physics and Electronic Information Engineering Hunan Institute of Humanities Sciences and Technology Loudi 417000 China Key State Laboratory of Magnetic Resonance and Atomic and Molecular Physics Institute of Physics and Mathematics the Chinese Academy of Sciences Wuhan 430071 China

In this paper, we find an analytic solution of the master equation of a non-resonant two-photon Jaynes- Cummings model （JCM） with phase damping with the help of the super-operator technique. We study the influence of phase damping on non-classical effects in the JCM, such as oscillations of the photon-number distribution, revivals of the atomic inversion, and sub-Possion photon statistics. It is demonstrated that the phase damping suppresses the revivals of the atomic inversion and non-classical effects of the cavity field in the JCM.

关键词： Jaynes-Cummings model (JCM) Milburn equation phase damping