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Implicit high-order discontinuous Galerkin method with HWENO type limiters for steady viscous flow simulations

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Acta Mechanica Sinica 2013年第4期29卷 526-533页

作者： zhen-Hua jiang Chao Yan Jian Yu College of Aeronautics Science and Engineering Beijing University of Aeronautics and Astronautics

Two types of implicit algorithms have been im- proved for high order discontinuous Galerkin （DG） method to solve compressible Navier-Stokes （NS） equations on tri- angular grids. A block lower-upper symmetric Gauss- Seidel （BLU-SGS） approach is implemented as a nonlin- ear iterative scheme. And a modified LU-SGS （LLU-SGS） approach is suggested to reduce the memory requirements while retain the good convergence performance of the origi- nal LU-SGS approach. Both implicit schemes have the sig- nificant advantage that only the diagonal block matrix is stored. The resulting implicit high-order DG methods are applied, in combination with Hermite weighted essentially non-oscillatory （HWENO） limiters, to solve viscous flow problems. Numerical results demonstrate that the present implicit methods are able to achieve significant efficiency improvements over explicit counterparts and for viscous flows with shocks, and the HWENO limiters can be used to achieve the desired essentially non-oscillatory shock tran- sition and the designed high-order accuracy simultaneously.

关键词： Discontinuous Galerkin (DG) scheme ~ Implicitmethod ~ HWENO ~ High order ~ Unstructured grids

Design of Personal Terminal DNS Agent

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Journal of Communications and Information Networks 2021年第3期6卷 251-266页

作者： Yongjia Liu Yu jiang ning Ge The Department of Electronic Engineering Tsinghua UniversityBeijing 100080China

As one of the most important Internet infrastructures,domain name system(DNS)is vulnerable to various attacks,and the issue of DNS security has received critical ***,most of the existing DNS security enhancements have encountered great difficulties in the process of *** main reason is that these enhancement measures usually focus on the server side,thus requiring changes to existing DNS protocol or architecture,while modifying the Internet infrastructure is inherently *** that the range of domain name frequently visited by a single user is much smaller than the entire domain system,in this paper we propose the idea of personal DNS agent(P-DNS),which migrates DNS security from servers to user terminals and can be applied without changing the current DNS infrastructure.P-DNS takes advantage of static and dynamic redundancy to enhance DNS ***,in the static redundancy phase,P-DNS improves the resolution efficiency by utilizing resolution results cached in *** in the dynamic redundancy stage,F-DNS improves the reliability of resolution results by querying multiple recursive name servers(RNSs).Simulation results show that our proposed architecture can effectively improve DNS security performance and greatly reduce the additional delay caused by redundancy.

关键词： DNS security terminal agent fault tolerance

Aerodynamic Characteristics of Isolated Loaded Tires with Different Tread Patterns: Experiment and Simulation

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 107-122页

作者： Haichao Zhou zhen jiang Guolin Wang Shupei Zhang School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang 212013China

The current research of tire aerodynamics mainly focus on the isolated and simplified tread *** with the real complex pattern tire,the tread pattern structure and deformed profile of a loaded tire has a greatly influence on tire aerodynamic ***,the mechanisms of the isolated loaded tires with different tread patterns effects on the aerodynamic drag are subjects worthy of *** purpose of this study is to experimentally and compu-tationally investigate the aerodynamic characteristics of three tires 185/65 R14 with different patterns under loaded.A wind tunnel test model was first established using three-dimensional(3D)printing with a ratio of 1:1,and the pres-sure coefficients C_(p) of the three tires with different patterns are *** paper then conducted computational fluid dynamics(CFD)simulations for analyzing the pressure and flow *** accuracy of CFD simulation is verified by comparing the simulation results with the test results of pressure coefficients C_(p),and they are of good ***,the general analysis of pressure coefficients C_(p) results of the three tires indicates high-pressure area on the windward surface,and occurrence of low-pressure area on the leeward surface,the pressure coefficients C_(p) of all three tires decreased firstly and then increased along in the air flow *** authors finally analyzed the effect of tread patterns on the flow field around the tire and revealed the differences between flow characteristics and aerodynamic *** results show that,angle of tire lateral groove has great effect on the flow field characteristics such that;the more the angle of lateral groove agrees with the air flow direction,the less the flow separation and flow vortices,and a minimum observable aerodynamic *** research provides a guidance for the design of low aerodynamic drag tires,and helps to illustrate the impact of tire aerodynamics on the car body in the future.

关键词： Tire aerodynamic Wind tunnel test Numerical simulation Flow analysis

Reaction mechanisms between molten CaF2-based slags and molten 9CrMoCoB steel

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 611-619页

作者： Lei-zhen Peng Zhou-hua jiang Xin Geng School of Metallurgy Northeastern UniversityShenyang 110819China

Investigating the reaction mechanism between slag and 9CrMoCoB steel is important to develop the proper slag and produce qualified ingots in the electroslag remelting(ESR) process. Equilibrium reaction experiments between molten 9CrMoCoB steel and the slags of 55 wt%CaF2–20 wt%CaO–3 wt%MgO–22 wt%Al2O3–xwt%B2O3(x = 0.0, 0.5, 1.0, 1.5, 2.0, 3.0) were conducted. The reaction mechanisms between molten 9 CrMoCoB steel and the slags with different B2O3 contents were deduced based on the composition of the steel and slag samples at different reaction times. Results show that B content in the steel can be controlled within the target range when the B2O3 content is 0.5 wt% and the FeO content ranges from 0.18 wt% to 0.22 wt% in the slag. When the B2O3 content is ≥1 wt%, the reaction between Si and B2O3 leads to the increase of the B content of steel. The additions of SiO2 and B2O3 to the slag should accord to the mass ratio of [B]/[Si] in the electrode, and SiO2 addition inhibits the reaction between Si and Al2O3.

关键词： 9CrMoCoB electroslag remelting B2O3 thermodynamic calculation reaction mechanism

The Galois Correspondence in Field Algebra of G-spin Model

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Acta Mathematica Sinica,English Series 2005年第4期21卷 673-680页

作者： Li ning jiang Mao zheng GUO Department of Mathematics Beijing Institute of Technology Beijing 100081. P. R. China LMAM Department of Mathematics Peking University. Beijing 100871. P. R. China

Suppose that G is a finite group and D（G） the double algebra of G. For a given subgroup H of G, there is a sub-Hopf algebra D（G; H） of D（G）. This paper gives the concrete construction of a D（G; H）-invariant su... 详细信息

关键词： G-spin model Double algebra Observable algebra Galois closed

The transport and retention of CQDs-doped TiO_(2) in packed columns and 3D printed micromodels

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Journal of Environmental Sciences 2022年第3期34卷 365-375页

作者： Tao Sun Jian Song zhen Liu Wei jiang Environment Research Institute Shandong UniversityQingdao 266237China Qingdao SKSS 3D Printing Technology Co.LTD. Qingdao 266111China Shenzhen Research Institute Shandong UniversityShenzhen 518057China

CQDs-doped TiO_(2)(C-TiO_(2))has drawn increased attention in recent because of its excellent catalytic *** the transport of C-TiO_(2)in porous media is necessary for evaluating the environmental process of this new *** experiments were used in this study to investigate ionic strength(IS),dissolved organic matter(DOM)and sand grain size on the transport of C-TiO_(2).The mobility of C-TiO_(2)was inhibited by the increased IS and decreased sand grain size,but was promoted by the increased DOM *** promotion efficiency of DOM ranked as humic acid(HA)>alginate(Alg)>bovine serum albumin(BSA),which was in the same order as their ability to change surface *** micromodels of pore network were prepared via 3D printing to further reveal the deposition mechanisms and spatial/temporal distribution of C-TiO_(2)in porous space.C-TiO_(2)mainly attached to the upstream region of collectors because of *** collector ripening was observed after long-time *** existence of DOM caused visible decrease of C-TiO_(2)deposition in the pore *** caused the most remarkable reduce of deposition in the three types of DOM,which was consistent with the column experiment *** research is helpful to predict the transport of C-TiO_(2)in natural porous media.

关键词： CQDs-doped HO_(2) Transport Dissolved organic matter Column experiment 3D-printed micromodel

Caspases control antiviral innate immunity

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Cellular & Molecular Immunology 2017年第9期14卷 736-747页

作者： Huihui Chen Xiaohan ning zhengfan jiang Shenzhen BOLI Pharmaceutical Co. LtdShenzhenGuangdong 518040China State Key Laboratory of Protein and Plant Gene Research School of Life SciencesPeking UniversityBeijing 100871China Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education School of Life SciencesPeking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Beijing 100871China

Caspases are a family of cysteine proteases whose functions have been scrutinized intensively in recent *** their established roles in programmed cell death and inflammatory response,some caspases are also fundamental players in antiviral immunity by fine-tuning the levels of antiviral signaling adapters and cytokines,such as type I interferons,which serves as a major,sophisticated weapon against *** infections can result in inflammasome activation and the initiation of cell death,including apoptosis and pyroptosis,and multiple caspases are significantly involved in these *** review will focus on the cutting-edge discoveries regarding the multifaceted roles of caspases in antiviral innate immunity.

关键词： apoptosis caspases I-IFNs inflammasome innate immunity

Multi-stage Dynamic Post-disaster Recovery Strategy for Distribution Networks Considering Integrated Energy and Transportation Networks

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CSEE Journal of Power and Energy Systems 2021年第2期7卷 408-420页

作者： Xinyi jiang Jian Chen Ming Chen zhen Wei Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong UniversityJinan 250061China State Grid Qingdao Power Supply Company Qingdao 266002China

To improve the resilience of distribution networks(DNs),a multi-stage dynamic recovery strategy is proposed in this paper,which is designed for post-disaster DN considering an integrated energy system(IES)and transportation network(TN).First,the emergency response quickly increases the output of gas turbines(GTs)in the natural gas network(NGN),and responsively reconfigures the DN in microgrids,to maximize the amount of loads to be *** single-commodity flow model is adopted to construct spanning tree ***,in the second stage of energy storage recovery,mobile energy storage systems(MESSs)are deployed to cover the shortages of power demands,i.e.,to further restore the loads after evaluating the load recovery *** Floyd algorithm based dynamic traffic assignment(DTA)is selected to obtain the optimal path of the *** the third stage,the outputs of various post-disaster recovery measures are adjusted to achieve an economically optimized *** studies demonstrate the effectiveness of the proposed dynamic post-disaster recovery strategy.

关键词： Dynamic post-disaster recovery dynamic transportation network integrated energy system resilience distribution

Association Testing for High-Dimensional Multiple Response Regression

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Journal of Systems Science & Complexity 2023年第4期36卷 1680-1696页

作者： WANG Jinjuan jiang zhenzhen LIU Hongzhi MENG zhen School of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100081China LSC Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Science University of Chinese Academy of SciencesBeijing 100190China Institute of Food Science and Technology Chinese Academy of Agricultural Sciences/Comprehensive Key Laboratory of Agricultural Products Processing and Quality ControlMinistry of AgricultureBeijingChina School of Statistics Capital University of Economics and BusinessBeijing 100070China

Multiple response regression model is commonly employed to investigate the relationship between multiple outcomes and a set of potential predictors,where single-response analysis and multivariate analysis of variance(MANOVA)are two frequently used methods for association ***,both methods have their own *** basis of the former method is independence of multiple responses and the latter one assumes that multiple responses are normally *** this work,the authors propose a test statistic for multiple response association analysis in high-dimensional situations based on F *** is free of normal distribution assumption and the asymptotic normal distribution is obtained under some regular *** computer simulations and four real data applications show its superiority over single-response analysis and MANOVA methods.

关键词： Association analysis high-dimensional multiple response multiple response regression non normality