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The Right Gorenstein Subcategory rg(l,D)

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Acta Mathematica Sinica,English Series 2023年第2期39卷 339-362页

作者： zeng hui GAO Wan WU College of Applied Mathematics Chengdu University of Information TechnologyChengdu610225China

In this paper,we generalize the idea of Song,Zhao and Huang[***.J.,70,483±504(2020)]and introduce the notion of right(left)Gorenstein subcategory rg(l,∂)(lg(l,D)),relative to two additive full subcategoriesφand∂of an abelian category *** the assumption thatφ⊆∂,we prove that the right Gorenstein subcategory rg(l,D)possesses many nice properties that it is closed under extensions,kernels of epimorphisms and direct ***φ⊆Dandφ⊥D,we show that the right Gorenstein subcategory rg(l,D)admits some kind of *** we discuss a resolution dimension for an object in A,called rg(l,D)-projective ***,we prove that if(U,V)is a hereditary cotorsion pair with kernelφhas enough injectives,such that U⊆Dand U⊥∂,then(rg(l,D),φφ)is a weak Auslander±Buchweitz context,whereφis the subcategory of A consisting of objects with finiteφ-projective dimension.

关键词： Right Gorenstein subcategory rg(l,D)-projective dimension cotorsion pair weak Auslander-Buchweitz context

The hydrodynamic interactions of an array of truncated circular cylinders as each cylinder oscillates independently with different prescribed modes

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Journal of Hydrodynamics 2013年第1期25卷 27-38页

作者： zeng Xiao-hui TANG Si-yi Institute of Mechanics Chinese Academy of Sciences

An analytical method based on the eigenfunction expansion and the Graf＇s addition theorem for Bessel functions is developed to study the hydrodynamic interactions of an array of truncated circular cylinders with each cylinder oscillating independently in different prescribed modes. The hydrodynamic radiation and diffraction of linear waves by such an array of cylinders are investigated and the analytical solutions of the velocity potentials are obtained. After comparisons for degenerated cases and program verifications, several cases for an array of truncated cylinders with each cylinder oscillating independently in surge, sway, heave, roll, and pitch modes with different prescribed amplitudes, are studied and the hydrodynamic forces and moments acting on the cylinders are obtained.

关键词： array of truncated circular cylinders independent oscillation radiation hydrodynamic interaction

Soil microbial attributes along a chronosequence of Scots pine(Pinus sylvestris var. mongolica) plantations in northern China

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Pedosphere 2020年第4期30卷 433-442页

作者： Xiaodong YAO Wenjing zeng hui zeng Wei WANG Department of Ecology College of Urban and Environment Sciences and Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871(China) School of Urban Planning and Design Peking University Shenzhen University TownShenzhen 518055(China)

Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.

关键词： soil microbial metabolism quotient(gCO2) soil basal respiration soil depth soil microbial biomass soil organic matter dynamics soil potential extracellular enzyme activity stand age

A review of isolation methods, structure features and bioactivities of polysaccharides from Dendrobium species

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Chinese Journal of Natural Medicines 2020年第1期18卷 1-27页

作者： YUE Han zeng hui DING Kan Glycochemistry and Glycobiology Lab Key Laboratoty of Receptor ResearchShanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of Chinese Academy of Sciences Beijing 100049China

Dendrobium,orchid,is a traditional Chinese herb medicine applied extensively as tonic and precious food for thousands of years recorded in ancient Chinese medical book"Shen Nong’s Materia Medica".It’s well known that bioactivities are usually related to the ingredients’*** on the previous research,Dendrobium species contain amino acid,sesquiterpenoids,alkaloids and *** the bioactive substances,carbohydrate shows extensive activities in antitumor,antiglycation,immune-enhancing,antivirus,antioxidant,antitumor and ***,as the main biologically active substance,the exact structures and latent activities of polysaccharides from Dendrobium species are widely focused *** this review,we focus on the advancements of extraction methods and diversity of structures and bioactivities of polysaccharides obtained from Dendrobium species.

关键词： Dendrobium Polysaccharides Bioactivities Structures

Motion stability of high-speed maglev systems in consideration of aerodynamic effects: a study of a single magnetic suspension system

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Acta Mechanica Sinica 2017年第6期33卷 1084-1094页

作者： Han Wu Xiao-hui zeng Yang Yu Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences State Key Laboratory of Hydraulic Engineering Simulation and Safety School of Civil Engineering Tianjin University

In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed,the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward,and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.

关键词： High-speed maglev system Critical speed Aerodynamic effect Motion stability

Lake microbiome composition determines community adaptability to warming perturbations

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Ecological Processes 2024年第2期13卷 177-191页

作者： Xiaotong Wu Qixing Zhou hui zeng Xiangang Hu Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education) Carbon Neutrality Interdisciplinary Science Centre/College of Environmental Science and Engineering Nankai University

Background Microbial communities are crucial for ecosystems. A central goal of microbial ecological research is to simplify the biodiversity in natural environments and quantify the functional roles to explore how the ecosystems respond under different environmental conditions. However, the research on the stability and dynamics of lake microbes in response to repeated warming stress is *** To exclude confounding environmental factors, we conducted a 20-day repeated warming simulation experiment to examine the composition and function dynamics of lake microbial *** Experimental warming significantly altered the community structure of bacteria instead of fungi. Microbial community structure, together with microbial biomass, jointly regulated the function of microbial communities. The plummeting of aerobic denitrifiers Pseudomonadaceae decreased by 99%(P < 0.001) after high temperature, leading to reduced microbial nitrogen metabolism on nitrogen respiration and nitrate respiration. Under warming conditions, the microbial community with higher adaptability showed more positive correlations and less competitive relationships in co-occurrence networks to acclimate to *** Microbiome composition controlled carbon and nitrogen metabolism, thus determining lake microbial communities' adaptability to heat stress. This study extended our insights on the lake microbial community response and adaptability under warming drivers.

关键词： Temperature Environmental stress Bacteria Fungi Freshwater ecosystem

Preparation of Wear Resistant Materials by Melting and Diffusion Process

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Journal of Wuhan University of Technology(Materials Science) 2012年第6期27卷 1072-1076页

作者：余世浩 WEI Xueping zeng hui School of Materials Science and Engineering Wuhan University of Technology Wuhan University of Technology Huaxia College Department of Electronics and Information Engineering Guangdong Jiaying CollegeMeizhou 514015China

A wear-resistant material reinforced with VCp was manufactured by the in-mold melting process, in which the high-vanadium alloy-rods were melted by high temperature liquid steel and elements diffused into the liquid. Microstructure of the material was examined by OM, SEM, and XRD, and alloy elements in the diffusion layer were studied by EDS, and the hardness of the material was tested by HRS. The experimental results show that the material gradually changes hardness, which is due to the uniformly existents of carbide particles on martensite matrix and the gradient distribution of vanadium and carbide.

关键词： in-mold melting elements diffused reinforced with VCp wear resistant

The Weighted Transience and Recurrence of Markov Processes

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Acta Mathematica Sinica,English Series 2007年第1期23卷 111-126页

作者： Min Zhi ZHAO hui zeng ZHANG Department of Mathematics Zhejing University Hangzhou 310027 P. R. China School of Computer and Computing Science Zhejiang University City College. Hangzhou 310015 P. R. China

Transience and recurrence are among the most important concepts in Markov processes. In this paper, we study the transience and recurrence for right processes with a given weight function, and characterize them by potentials, excessive functions, first hitting times and last exit times of the process. We also study the properties of recurrent states.

关键词： ω-recurrence ω-transience last exit time right process

A novel optimization method of transient stability emergency control based on practical dynamic security region (PDSR) of power systems

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Science China(Technological Sciences) 2004年第3期47卷 376-384页

作者： YU Yixin LIU hui zeng Yuan School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

This paper proposes a novel optimization method of transient stability emergency control based on a new concept of the so-called extended practical dynamic security region (EPDSR) defined in this paper and four experiential laws about the EPDSRs found from a number of studies in real power systems. In this method, the effect of a control action is represented by the displacement of EPDSRs critical hyper-plane boundary in the direction of its outer normal vector. If an unstable contingency occurs, appropriate emergency control actions are triggered so that the enlarged EPDSR can cover the current operating point. Based on these ideas, a mathematics model of emergency control strategy is developed for minimizing its total cost and guaranteeing power system transient stability. The simulation results on the 10-generator, 39-bus New-England Test System as well as other real power systems have shown the validity of this method.

关键词： emergency control, transient stability, EPDSR, critical hyper-plane boundary, experiential law