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HIGH-RESOLUTION SEMI-DISCRETE CENTRAL SCHEME FOR DAM-BREAK PROBLEMS

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Journal of Hydrodynamics 2005年第5期17卷 585-589页

作者： CHEN jian-zhong SHI zhong-ke College of Automation Northwestern Polytechnical University Xi＇an 710072 China

A numerical model for simulating the dambreak problems was presented. The model was based on a high-resolution semi-discrete central-upwind difference scheme. In order to reduce spurious oscillation, the uniformly non-oscillatory limiter was employed. A third-order total variation diminishing Runge-Kutta method is used for time integration. The main feature of the presented method is its simplicity. It requires no Riemann solvers, no flux splitting and no flux limiter. It is explicit and does not require dimensional splitting for two dimensions. The Simpson quadrature rule was employed to compute the source term. To verify the effectiveness and accuracy of the proposed method, the 1D dambreak, circular dam-break and partial dam-break problems were simulated. The results are shown to be in good agreement with analytical solution and numerical results obtained by other methods.

关键词： dam-break shallow water equations central-upwind difference scheme

An Improved SAR Image Denoising Method Based on Bootstrap Statistical Estimation with ICA Basis

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Chinese Journal of Electronics 2016年第4期25卷 786-792页

作者： ji jian LI Yang School of Computer Science and Technology Xidian University Shaanxi Automobile Group Co. Ltd

A new method for Synthetic aperture radar(SAR) image denoising is *** prior information of speckle statistical model can be exploited to judge its *** basis of SAR image can be estimated by Independent component analysis(ICA),and these bases can be divided into two different subspaces(noise and real signal subspaces) through a linear *** parametric Bootstrap estimates the parameters of speckle statistical model on the noise signal subspace,and the nonparametric Bootstrap can estimate the distribution of real image on the real signal *** to different results estimated by Bootstrap,corresponding Maximum a posterior probability(MAP) filter will be selected for image denoising,using the noise model’s parameter for adaptive *** show that the image processed by this new method can achieve a better visual perception and objective evaluation results.

关键词： Synthetic aperture radar(SAR) Image denoising Independent component analysis(ICA) basis Bootstrap Maximum a posterior probability(MAP)

Effects of Zn content on the microstructure and the mechanical and corrosion properties of as-cast low-alloyed Mg–Zn–Ca alloys

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International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 800-809页

作者： Hong-xiang Li Shi-kai Qin Hng-zhong Ma jian WanE Yun-jin Liu ji-shan Zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

The effects of Zn content on the microstxucture and the mechanical and corrosion properties of as-cast low-alloyed Mg-xZn~.2Ca alloys （x = 0.6wt%, 2.0wt%, 2.5wt%, hereafter denoted as 0.6Zn, 2.0Zn, and 2.5Zn alloys, respectively） axe investigated. The results show that the Zn content not only influences grain refinement but also induces different phase precipitation behaviors. The as-cast microstxucture of the 0.6Zn alloy is composed of ct-Mg, Mg2Ca, and Ca2Mg6Zn3 phases, whereas 2.0Zn and 2.5Zn alloys only contain ct-Mg and Ca2Mg6Zn3 phases, as revealed by X-ray diffraction （XRD） and txonsmission electron microscopy （TEM） analyses. Moreover, with in- creasing Zn content, both the ultimate tensile strength （UTS） and the elongation to fracture first increase and then decrease. Among the three investigated alloys, the largest UTS （178 MPa） and the highest elongation to fracture （6.5%） are obtained for the 2.0Zn alloy. In addition, the corrosion rate increases with increasing Zn content. This paper provides on updated investigation of the alloy composi- tion-microstxucture-property relationships of different Zn-containing Mg-Zn-Ca alloys.

关键词： Mg-Zn-Ca alloy s as-cast micro stxucture mechanical properties corrosion properties

SOLUTION OF 2D SHALLOW WATER EQUATIONS BY GENUINELY MULTIDIMENSIONAL SEMI-DISCRETE CENTRAL SCHEME

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Journal of Hydrodynamics 2006年第4期18卷 436-442页

作者： CHEN jian-zhong, SHI zhong-ke College of Automation Northwestern Polytechnical University Xi＇an 710072 China

A numerical two-dimensional shallow water method was based on method for solving the equations was presented. This the third-order genuinely multidimensional semi-discrete central scheme for spatial discretization and the optimal third-order Strong Stability Preserving （SSP） Runge-Kutta method for time integration. The third-order compact Central Weighted Essentially Non-Oscillatory （CWENO） reconstruction was adopted to guarantee the non-oscillatory behavior of the presented scheme and improve the resolution. Two kinds of source terms were considered in this work. They were evaluated using different approaches. The resulting scheme does not require Riemann solvers or characteristic decomposition, hence it retains all the attractive features of central schemes such as simplicity and high resolution. To evaluate the performance of the presented scheme, several numerical examples were tested. The results demonstrate that our method is efficient, stable and robust.

关键词： 2D shallow water equations semi-discrete central scheme Central Weighted Essentially Non-Oscil]atory (CWENO) reconstruction

Decoupled thermal–hydraulic analysis of an air-cooled separated heat pipe for spent fuel pools under natural convection

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Nuclear Science and Techniques 2023年第6期34卷 183-197页

作者： Hui-Lin Xue jian-jie Cheng Wei-Hao ji Wen-jin Li Han-zhong Tao Wei Li College of Urban Construction Nanjing Tech UniversityNanjing211800China School of Energy Science and Engineering Nanjing Tech UniversityNanjing211800China

An investigation of the decoupled thermal–hydraulic analysis of a separated heat pipe spent fuel pool passive cooling system(SFS)is essential for practical engineering *** on the principles of thermal and mass balance,this study decoupled the heat transfer processes in the *** accordance with the decoupling conditions,we modeled the spent fuel pool of the CAP1400 pressurized water reactor in Weihai and used computational fluid dynamics to explore the heat dissipation capacity of the SFS under different air temperatures and wind *** results show that the air-cooled separated heat pipe radiator achieved optimal performance at an air temperature of 10℃ or wind speed of 8 m/*** equations for the equivalent thermal conductivity of the separated heat pipes with the wind speed and air temperature we obtained according to the thermal resistance network *** study is instructive for the actual operation of an SFS.

关键词： Decoupled analysis Separated heat pipe CAP1400 Finned tube radiator Passive cooling

Adenosylhopane Biosynthesis by the Radical SAM Enzyme HpnH

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Chinese Journal of Chemistry 2020年第2期38卷 218-219页

作者： Yuting zhong Xinjian ji Department of Chemistry Fudan UniversityShanghai 200433China

The radical S-adenosylmethinone(SAM)superfamily is currently the largest known enzyme superfamily that consists of more than 22000 members.[1]These enzymes utilize a[4Fe-4S]cluster to bind SAM and reductively cleave it to produce a highly reactive 5'-deoxyadenosyl(dAdo)*** alkyl radical abstracts a hydrogen atom from the substrate to produce 5'-deoxyadenosine(dAdoH)and a substrate radical,thereby initiating remarkably diverse reactions.[1]

关键词： radical utilize thereby

Halloween genes AhCYP307A2 and AhCYP314A1 modulate last instar larva–pupa–adult transition, ovarian development and oogenesis in Agasicles hygrophila (Coleoptera:Chrysomelidae)

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Journal of Integrative Agriculture 2023年第3期22卷 812-824页

作者： jiN ji-su LIU Yi-ran ZHOU zhong-shi WAN Fang-hao GUO jian-ying State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193P.R.China Agricultural Genomics Institute at Shenzhen Chinese Academy of Agricultural SciencesShenzhen 518120P.R.China

In insects,ecdysteroids are synthesized by genes of the Halloween family and play important roles in several key developmental events,including molting and ***,the roles of these genes in Agasicles hygrophila are still largely *** this study,the expression patterns of the two Halloween genes AhCYP307A2 and AhCYP314A1 were determined by quantitative PCR(qPCR)at different developmental ***,the functions of these two genes were explored using RNA interference(RNAi),and ovarian development was observed by dissecting the ovaries of *** *** qPCR results showed that AhCYP307A2 and AhCYP314A1 were highly expressed in last instar larvae and in adult *** addition,AhCYP307A2 was also highly expressed in eggs and pupae but was markedly lower than in third-instar larvae and *** RNAi results showed that the injection of dsAhCYP307A2 or dsAhCYP314A1 markedly inhibited their expression and the transcription levels of three related *** of AhCYP307A2 or AhCYP314A1 significantly inhibited larval molting,impaired last instar larva–pupa–adult transition,delayed ovarian development,and stopped egg production(i.e.,no eggs were laid).These results indicate that AhCYP307A2 and AhCYP314A1 play important regulatory roles in last instar larva–pupa–adult transition and reproduction in ***.

关键词： Agasicles hygrophila ovary oogenesis AhCYP307A2 AhCYP314A1 RNA interference

Recent progress in self-propelled particles

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Journal of Hydrodynamics 2024年第1期36卷 61-77页

作者： Zhen-yu Ouyang jian-zhong Lin Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo315201China Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou310027China

Self-propelled particles are commonly found in a large number of planktonic organisms such as bacteria,fungi,and algae in nature,and researchers have taken a long interest in exploring their swimming mechanisms for more than a *** in the past 20 years,with the development of computational fluid dynamics and flow display technology,as well as the need for the design of synthetic self-propelled particles and micro-swimming devices,self-propelled particles have become the forefront and hotspot of current research in the field of fluid *** paper first introduces the swimming characteristics of common self-propelled particles,leading to a classic“squirmer”type self-propelled particle *** this basis,a systematic introduction and summary of the theoretical and numerical simulation research of“squirmer”will be ***,the main challenges and opportunities faced by the current research will be summarized.

关键词： Self-propelled particles multiphase flow hydrodynamic interaction

openGauss: An Open-Source Database for the Era of Artificial Intelligence

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JOURNAL OF COMPUTER SCIENCE AND TECHNOLOGY 2024年第5期39卷 1005-1006页

作者： Li, jian-zhong Shenzhen Inst Adv Technol Shenzhen 518055 Peoples R China Harbin Inst Technol Sch Comp Sci & Technol Harbin 150001 Peoples R China

Databases play a vital role in data management in many fields,such as finance,government,telecommunications,energy,electricity,transportation,*** the database management system has become a core foundational *** is an enterprise-grade open-source database,a product of deep integration of research and development from Huawei,Tsinghua University,and China Mobile in the past decade.

关键词： database Open finance