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Abnormal nonlinear optical responses on the surface of topological materials

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npj Computational Materials 2022年第1期8卷 1045-1052页

作者： Haowei Xu hua wang Ju Li Department of Nuclear Science and Engineering Massachusetts Institute of TechnologyCambridgeMA02139USA Department of Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA02139USA

The nonlinear optical(NLO)responses of topological materials are under active *** previous works studied the surface and bulk NLO responses *** we develop a generic Green’s function framework to investigate the surface and bulk NLO responses *** reveal that the topological surface can behave disparately from the bulk under light ***,the photocurrents on the surface can flow in opposite directions to those in the bulk interior,and the light-induced spin current on the surface can be orders of magnitude stronger than its bulk counterpart on a per-volume *** also study the responses under inhomogeneous field and higher-order NLO effect,which are all distinct on the *** anomalous surface responses suggest that light can be a valuable tool for probing the surface states of topological ***,the surface effects should be prudently considered when investigating the optical properties of topological materials.

关键词： materials. surface. topological

From reflux esophagitis to Barrett's esophagus and esophageal adenocarcinoma

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World Journal of Gastroenterology 2015年第17期21卷 5210-5219页

作者： Rui-hua wang Department of Gastroenterology Shanghai Jiao Tong University affiliated Sixth People’s Hospital South Campus

The occurrence of gastroesophageal reflux disease is common in the human *** all cases of esophageal adenocarcinoma are derived from Barrett's esophagus,which is a complication of esophageal adenocarcinoma precancerous *** exposure of the esophagus to gastroduodenal intestinal fluid is an important determinant factor in the development of Barrett's *** replacement of normal squamous epithelium with specific columnar epithelium in the lower esophagus induced by the chronic exposure to gastroduodenal fluid could lead to intestinal metaplasia,which is closely associated with the development of esophageal ***,the exact mechanism of injury is not completely *** animal models of the developmental mechanisms of disease,and theoretical and clinical effects of drug treatment have been widely used in ***,animal models employed in studies on gastroesophageal reflux injury have allowed significant *** advantage of using animal models lies in the ability to accurately control the experimental conditions for better evaluation of *** this article,various modeling methods are reviewed,with discussion of the major findings on the developmental mechanism of Barrett's esophagus,which should help to develop better prevention and treatment strategies for Barrett's esophagus.

关键词： Animal models Gastroesophageal refluxdisease Reflux esophagitis Barrett's esophagus Esophageal adenocarcinoma

Comparative study on the reaction of methane over a ZnO bed in the absence and presence of CO_2

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Journal of Natural Gas Chemistry 2008年第1期17卷 81-86页

作者： Xianquan Ao hua wang Yonggang Wei Faculty of Materials and Metallurgy Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China Faculty of Chemical Engineering Guizhou University Guizhou 550003 Guiyang China

The reaction of zinc oxide with methane in the absence and presence of CO2 were theoretically and experimentally investigated using HSC Chemistry 5.1 software and a fixed bed reactor, respectively. In the absence of CO2 at 1193 K, the reduction of ZnO was accompanied with methane cracking, and metallic zinc, CO, and H2 were the main reaction products. This system could be utilized for the co-production of metallic zinc and synthesis gas, in which ZnO was a donor of oxygen. In the presence of CO2, ZnO plays as a catalyst in the CO2 reforming of methane and produces syngas with the average H2/CO ratio of 0.88 at 1193 K, which was close to the total reaction theoretic value of 1. It was also found that higher temperature favored high CH4 and CO2 conversions. XRD technique was used to characterize the ZnO species. The result showed that there were no differences in the peak profiles of the XRD patterns of the ZnO powder obtained before and after passing the CH4/CO2 mixed gases for 6 h at 1193 K. It is suggested that ZnO functions as a catalyst according to the redox cycle and metallic zinc plays the role of intermediate product in this process.

关键词： methane synthesis gas, ZnO CO2 reforming catalysis

RATE OF CONVERGENCE OF SCHWARZ ALTERNATING METHOD FOR TIME-DEPENDENT CONVECTION-DIFFUSION PROBLEM

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Journal of Computational Mathematics 2002年第5期20卷 479-490页

作者： Jian-wei Hu Cai-hua wang School of Mathematical Sciences Nankai University300071 Tianjin China Laboratory of Computational Physics IAPCM100088 Beijing China Department of Mathematics Tianjin Normal University300073 Tianjin China

Presents a study that examined the application of an overlapping domain decomposition method to the solution of time-dependent convection-diffusion problems. Background on the Schwartz alternating procedure; Applicati... 详细信息

关键词： rate of convergence Schwarz alternating method convection-diffusion problem

Pressure-induced magnetic transition in Nd_(2)Fe_(14)B based on two-sublattice model

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Rare Metals 2022年第1期41卷 232-239页

作者： Feng Lu Shuo Xu Li-hua wang Institute of Fisheries Engineering Chinese Academy of Fishery SciencesBeijing 100141China

To analyze the magnetic properties of Nd_(2)Fe_(14)B compound under high pressure,an improved two-sublattice molecular field model coupled with equivalent stress field was applied to study the effect of pressure on magnetization,magnetostriction coefficient,susceptibility and Curie *** calculation results show that the pressure has a stronger effect on the magnetization of Fe sublattice compared to that of Nd sublattice at varied temperatures when the external magnetic field is parallel to the alignment *** magnetization,initial susceptibility and magnetic moment of Nd_(2)Fe_(14)B compound are found to decrease gradually with pressure increasing,and the Curie temperature of Nd_(2)Fe_(14)B decreases to about 298 K under an applied pressure of 1.15 *** results suggest that the pressure-induced magnetic phase transition of Nd2Fe14B occurs under 1.15 GPa at room temperature.

关键词： Magnetization Curie temperature Molecular field theory Nd_(2)Fe_(14)B

Scattering Theory for the Defocusing Fourth Order NLS with Potentials

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Acta Mathematica Sinica,English Series 2018年第4期34卷 773-786页

作者： Hong Liang FENG hua wang Xiao hua YAO School of Mathematics and Statistics Central China Normal University Wuhan 430079 P. R. China School of Mathematics and Statistics and Hubei Province Key Laboratory of Mathematical Physics Central China Normal University Wuhan 430079 P. R. China

Based on the endpoint Strichartz estimates for the fourth order SchrSdinger equation with potentials for n ≥ 5 by [Feng, H., Softer, A., Yao, X.： Decay estimates and Strichartz estimates of the fourth-order Schr6dinger operator. J. Funct. Anal., 274, 605-658 （2018）], in this paper, the authors further derive Strichartz type estimates with gain of derivatives similar to the one in [Pausader, B.： The cubic fourth-order Schr6dinger equation. J. Funct. Anal., 256, 2473-2517 （2009）]. As their applications, we combine the classical Morawetz estimate and the interaction Morawetz estimate to establish scattering theory in the energy space for the defocusing fourth order NLS with potentials and pure power nonlinearity 1 ＋ 8/n〈 p 〈 1 ＋ 8/n-4 in dimensions n ≥ 7. n

关键词： Fourth order NLS potential morawetz estimate scattering

A new color image encryption scheme based on chaos synchronization of time-delay Lorenz system

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Advances in Manufacturing 2016年第4期4卷 348-354页

作者： hua wang Hang-Feng Liang Zhong-hua Miao Shanghai Key Laboratory of Power Station AutomationTechnology School of Meehatronic Engineering andAutomation Shanghai University Shanghai 200072People's Republic of China

In this paper, a new image encryption scheme is presented based on time-delay chaos synchronization. Compared with existing methods, a new method is pro- posed and a lot of coupled items can be taken as zero items to simplify the whole system. A simple linear controller is introduced to realize time-delay chaos synchronization and image encryption. The positions of the image pixels are firstly shuffled and then be hidden in the cartier image. The address codes of the chaotic sequences are adopted to avoid the disturbances induced by the initial value and computer accuracy error. Simulation results for color image are provided to illustrate the effectiveness of the proposed method. It can be seen clearly that the system can converge quickly and the image can be encrypted rapidly.

关键词： Delay chaotic system Chaos synchronization Linear controller Color image encryption Address code

Scale effects on bow wave breaking of KCS ship model:Insights from DDES investigations

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Journal of Hydrodynamics 2023年第4期35卷 668-678页

作者： Jian-hua wang Wen-tao wang De-cheng Wan Computational Marine Hydrodynamics Laboratory(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China China Ship Scientific Research Center Wuxi214082China

Ship bow wave breaking is a common phenomenon during navigation,involving complex multi-scale flow ***,the understanding of this intense free surface flow issue is not sufficiently deep,especially regarding the lack of research on the impact of scale effects on bow wave *** paper focuses on the benchmark ship model KCS and conducts numerical simulations and comparative analyses of bow wave breaking for three model scales under the condition of Fr=*** numerical calculations were performed using the in-house computational fluid dynamics(CFD)solver naoe-FOAM-SJTU,which is developed on the open source platform *** detached eddy simulation(DDES)method is utilized to calculate the viscous flow field around the ship *** present method was validated through measurement data of wave profiles and wake flows obtained from model *** field results for three different scales,including bow wave profiles,vorticity at various sections,and wake distribution,were presented and *** results indicate that there is small difference in the bow wave overturning and breaking for the first two occurrences across different ***,considerable effects of scale are observed on the temporal and spatial variations of the free surface breaking pattern after the second *** findings of this study can serve as valuable data references for the analysis of scale effects in ship bow wave breaking phenomena.

关键词： Scale effects wave pattern bow wave breaking KRSIO Container Ship(KCS) delayed detached eddy simulation(DDES)approach

Global Well-posedness of the 3D Generalized Rotating Magnetohydrodynamics Equations

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Acta Mathematica Sinica,English Series 2018年第6期34卷 992-1000页

作者： Wei hua wang Gang WU School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper, we establish the global well-posedness of the generalized rotating mag- netohydrodynamics equations if the initial data are in χ^1-2α defined by χ^1-2α {u ∈D＇（R^3）：fR^3｜｜^1-2αu^^（ξ）｜d... 详细信息

关键词： Magnetohydrodynamics fractional MHD incompressible rotation framework Coriolis force