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Effect of Sintering Temperature on the Microstructure and Mechanical Properties of Nanocrystalline Cemented Carbide

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 664-672页

作者：陈先富刘颖 YE Jinwen wang lu School of Materials Science and Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Advanced Special Ma-terial&Technology Ministry of EducationChengdu 610065China

WC-Co nanocrystalline nitrogen-containing cemented carbides were prepared by vacuum sintering and low pressure *** sintering processes of Cr_(2)(C,N)doped nano WC-Co powders were studied by using thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The effect of sintering temperature on the microstructure and mechanical properties of nanocrystalline cemented carbide was studied by scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM)and mechanical property *** results showed that the nano WC grains began to grow in the solid phase sintering stage.A high-performance nano-nitrogen-containing cemented carbide with uniform microstructure and good interfacial bonding can be obtained by increasing the sintering temperature to 1380℃.It has a transverse rupture strength(TRS)of 5057 MPa and a hardness of 1956 HV30.

关键词： nano nitrogen cemented carbide sintering temperature microstructure mechanical properties

Evolutionary game analysis of information service quality control of e-commerce platforms under information ecology

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Journal of Management Analytics 2024年第1期11卷 135-159页

作者： Xiaojun Xu lu wang Xiaoli wang School of Economics and Management Yanshan UniversityQinhuangdaoPeople’s Republic of China

Due to the information asymmetry and imperfect supervision system,the problem of information service quality of e-commerce platforms is becoming increasingly *** on the perspective of information ecology,this paper constructs a three-party evolutionary game model including merchants,e-commerce platforms and governments,and analyzes the dynamic process of the threeparty game under bounded rationality,thereby characterizing the behavior and optimal strategies of information service quality *** carry out numerical simulation using data of the Pinduoduo *** results show that the cost of each party,control strength of e-commerce platforms,proportion of margin deducted and other factors are important factors affecting the quality of information service;Only when the sum of the costs of passive management of e-commerce platforms,penalties for merchants,and the additional revenue generated from the active management exceeds the cost of the active management of the e-commerce platforms,it ensures effective control over the quality of information service in a stable market ***,some suggestions are put forward to optimize the e-commerce information service quality control.

关键词： E-commerce platforms information service quality control evolutionary game information ecology

Asymmetric copolyimide membranes fabricated by nonsolvent-induced phase separation for He/CH_(4) and He/N_(2) separation

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 97-106页

作者： Ying Li lu wang Junyan Xie Yong Dai Xuehong Gu Xuerui wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Quzhou Membrane Material Innovation Institute Quzhou 324000China

Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature ***,the membrane performance was strongly limited by the trade-off between permeance and ***,novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(APAF)-5-amino-2-(4-aminobenzene)benzimidazole(BIA)asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation *** membrane performance was modulated by regulating dope solution compositions(e.g.,tetrahydrofuran and polymer concentration).The ideal He/CH_(4) selectivity was 124 and the optimized He permeance reached 87 GPU,beyond the current upper ***/CH_(4) selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol%*** membrane showed good resistance to CO_(2) and C_(2)H_(6),which are the typical impurities in natural *** 6FDA-APAF-BIA membranes have good stability(>160 h),which can provide great potential in He extraction from natural gas.

关键词： He separation membrane natural gas copolyimide

Creep constitutive model considering nonlinear creep degradation of fractured rock

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International Journal of Mining Science and Technology 2024年第1期34卷 105-116页

作者： wang Chunping Liu Jianfeng Chen Liang Liu Jian wang lu Liao Yilin Beijing Research Institute of Uranium Geology Beijing 100029China CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste Beijing 100029China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China School of Architecture and Civil Engineering Xihua UniversityChengdu 610039China

Stability analysis of underground constructions requires a model study of rock masses’ long-term performance. Creep tests under different stress conditions was conducted on intact granite and granite samples fractured at 30° and 45° angles. The experimental results indicate that the steady creep strain rates of intact and fractured rock present an exponential increase trend with the increase of stress level. A nonlinear creep model is developed based on the experimental results, in which the initial damage caused by fracture together with the damage caused by constant load have been taken into consideration. The fitting analysis results indicated that the model proposed is more accurate at identifying the full creep regions in fractured granite, especially the accelerated stage of creep deformation. The least-square fit error of the proposed creep model is significantly lower than that of Nishihara model by almost an order of magnitude. An analysis of the effects of elastic modulus, viscosity coefficient, and damage factors on fractured rock strain rate and creep strain is conducted. If no consideration is given to the effects of the damage, the proposed nonlinear creep model can degenerate into to the classical Nishihara model.

关键词： Fractured rock Damage Creep Beishan granite Geological disposal

Temperature dependence of mechanical properties and damage evolution of hot dry rocks under rapid cooling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 645-660页

作者： Longjun Dong Yihan Zhang Lichang wang lu wang Shen Zhang School of Resources and Safety Engineering Central South UniversityChangsha410083China School of Geosciences and Info-physics Central South UniversityChangsha410083China

Understanding the differences in mechanical properties and damage characteristics of granitoid under high temperatures is crucial for exploring deep geothermal *** study analyzes the evolution of the acoustic emission(AE)characteristics and mechanical parameters of granodiorite and granite after heating and water cooling by uniaxial compression and variable-angle shear tests under different temperature *** identify their changes in mesostructure and mineral composition with electron probe microanalysis and scanning electron *** show that these two hot dry rocks have similar diagenetic minerals and microstructure,but show significantly different mechanical and acoustic characteristics,and even opposing evolution trends in a certain temperature *** the temperatures ranging from 100℃to 500℃,the compressive and shear mechanical properties of granodiorite switch repeatedly between weakening and strengthening,and those of granite show a continuous weakening *** 600℃,both rocks exhibit a deterioration of mechanical *** damage mode of granite is characterized by initiating at low stress,exponential evolutionary activity,and intensified energy *** contrast,granodiorite exhibits the characteristics of initiating at high stress,volatile evolutionary activity,and intermittent energy release,due to its more stable microstructure and fewer thermal defects compared to *** the temperature increases,the initiation and propagation of secondary cracks in granodiorite are suppressed to a certain extent,and the seismicity and brittleness are *** subtle differences in grain size,microscopic heterogeneity,and mineral composition of the two hot dry rocks determine the different acoustic-mechanical characteristics under heating and cooling,and the evolution trends with *** findings are of great significance for the scientific and efficient construction of rock mass engineering by rationally utilizin

关键词： Hot dry rock Acoustic emission Mechanical properties High temperature Damage

Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

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China Ocean Engineering 2024年第1期38卷 1-17页

作者： DING Xiao-de ZHANG Jian wang Fang JIAO Hui-feng wang Ming-lu School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Shanghai Engineering Research Center of Marine Renewable Energy College of Engineering Science and Technol-ogyShanghai Ocean UniversityShanghai 201306China China Ship Scientific Research Center Wuxi 214082China

The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater ***,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape *** critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s *** numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were *** results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical *** formula can be extended to estimate the buckling capacity of water-drop-shaped pressure *** addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping ***,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical *** experimental results were consistent with the numerical *** results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt *** paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.

关键词： buckling pressure hull water drop underwater observatory

Towards Achieving Carbon Neutrality: The Role of Vegetation Restoration in Karst Regions of Southwest China

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Journal of Earth Science 2024年第3期35卷 1044-1048页

作者： Yuemin Yue lu wang Xinbao Zhang Kelin wang Guangxi Key Laboratory of Karst Ecological Processes and Services Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Huanjiang Observation and Research Station for Karst Ecosystem Chinese Academy of SciencesHuanjiang 547100China Chengdu Institute of Mountain Disasters and Environment Chinese Academy of Sciences&Ministry of Water ResourcesChengdu 610041China

Karst regions of Southwest China become a hotspot for global greening through large-scale vegetation restoration in recent two ***,the unique,fragile geological setting of carbonate rocks affects the sustainability of vegetation ***,we summarize and evaluate the impacts of the rock and soil compositions of karst landscapes on the types and quality of vegetation *** introduce the concept of“soil mass”and establish its relationship with aboveground vegetation biomass across varying degrees of rocky *** mineral nutrients and soil mass constrain the potential of vegetation carbon sequestration in karst *** enhance the sustainability of vegetation restoration and carbon sequestration under karst geological constraints,we suggest to push ecological intensification of tree plantations and optimize the zoning and classification of rocky desertification treatment,and these restoration initiatives will foster vegetation restoration to serve as a pivotal pathway towards carbon neutrality.

关键词： soil karst Restoration

Surface chemical microenvironment engineering of catalysts by organic molecules for boosting electrocatalytic reaction

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Chinese Chemical Letters 2024年第8期35卷 15-24页

作者： Xianxu Chu lu wang Junru Li Hui Xu Henan Key Laboratory of Biomolecular Recognition and Sensing College of Chemistry and Chemical EngineeringShangqiu Normal UniversityShangqiu 476000China Key Laboratory of Advanced Catalytic Materials and Technology Advanced Catalysis and Green Manufacturing Collaborative Innovation CenterChangzhou UniversityChangzhou 213164China

Electrocatalysis is a surface-sensitive process,in which the catalytic activity of electrocatalyst highly re-lates to the surface adsorption/desorption behaviors of the reactants/intermediates/products on the cat-alytically active *** chemical microenvironment engineering via organic molecules functional-ization is a promising strategy to tune the electrocatalytic activity since it can well modify the elec-trode/electrolyte interface and alter the reaction *** this review,we summarize the recent progress of surface microenvironment engineering of electrocatalysts induced by organic molecules func-tionalization,with the special focus on the organic molecule-assisted growth mechanism and unique electronic *** importantly,the applications of organic molecule functionalized catalysts in var-ious electrocatalytic reactions are also systematically summarized,along with a deep discussion on the conclusion and *** work will open a new avenue for the construction and modification of advanced electrocatalysts based on organic molecule-mediated interface engineering.

关键词： Chemical microenvironment engineering Organic molecules Electrocatalysis Functionalization Interface

Effect of(Cr,V)_(2)(C,N)on the Microstructure and Mechanical Properties of WC-10Co Cemented Carbides

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1138-1148页

作者： LI Xiangkun wang lu YE Jinwen School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

WC-10Co cemented carbides with finer WC and narrower grain size distributions are produced by using(Cr,V)_(2)(C,N)as grain growth *** a result,with the increase of(Cr_(0.9),V_(0.1))_(2)(C,N)and(V_(0.9),Cr_(0.1))_(2)(C,N),the grains size of WC and mean free path of Co phase decrease,and adjacency of WC *** and homogenization of grains enhance the transverse rupture strength(TRS)and the ***,the deflection and bridging of cracks keep the fracture toughness at a respectable *** WC-10Co-0.6(Cr_(0.9),V_(0.1))_(2)(C,N)-0.025(V_(0.9),Cr_(0.1))_(2)(C,N)cemented carbides exhibit excellent comprehensive mechanical properties with the TRS of 4602.6 MPa,hardness of 1835 kg/mm^(2),and fracture toughness of 10.39 MPa·m^(1/2),***,the large pores are caused by excess N larger than 0.03 wt%and deteriorates the mechanical *** provide a new approach to WC-Co cemented carbides preparation with a narrow grain size distribution by adding novel grain growth inhibitors.

关键词： (Cr,V)_(2)(C,N) nutrient content WC grains size microstructure mechanical properties