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Improving fatigue properties of normal direction ultrasonic vibration assisted face grinding Inconel 718 by regulating machined surface integrity

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International Journal of Extreme Manufacturing 2024年第3期6卷 458-475页

作者： Nianwei Xu Renke kang Bi Zhang Yuan Zhang Chenxu wang Yan Bao Zhigang Dong State Key Laboratory of High-Performance Precision Manufacturing Dalian University of TechnologyDalian 116024People’s Republic of China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China

Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining ***-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue *** lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue *** this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was ***,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was *** on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were *** predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI ***,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted *** to the critical condition,an SI field where FCI sites appeared in the bulk material could be *** this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.

关键词： surface integrity fatigue strength Inconel 718 ultrasonic assisted grinding

Coupling and coordinated evolution characteristics of regional economy-energy-carbon emission multiple systems:A case study of main China's Basin

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Journal of Environmental Sciences 2024年第6期140卷 204-218页

作者： Lu Chen Xin Li Jingyi Zhao Xinyu kang Lu Liu Minxi wang Wu Chen College of Management Science Chengdu University of TechnologyChengdu 610051China SDU Life Cycle Engineering Department of Green TechnologyUniversity of Southern Denmark5230 OdenseDenmark

Comprehensive analysis of the Economy-Energy-Carbon Emission(EECE)system is beneficial for promoting sustainable social *** study analyzes the system development of major watersheds in China from 2010 to *** research fully considers the system’s internal and external inputs and outputs and proposes an evaluation index system for regional EECE coupling and coordinated ***,using the difference in system weight allocation to improve the coupling and coordination model,the study explores the dynamic system’s coupling and *** results show that(1)The development of the system structure is relatively stable,but the overall development status is not ideal;(2)The downstream of China’s main river basins has obvious economic advantages,while the energy system fluctuates *** efficiency of the carbon emission system will decrease in areas with rapid economic *** coupling and coordination level of the EECE system is better in the Yangtze River Basin than in the Yellow River Basin;(3)From the perspective of dynamic coordinated development,the main river basins have been divided into two states since 2012,but it is relatively stable *** dynamic coordination is often at a disadvantage in regions with rapid economic and energy development;(4)The coupling coordination degree of the two river basins has significant positive spatial *** provinces’significant spatial clustering characteristics of the coupling coordination degree are High-High ***-Low type provinces are mainly concentrated *** research process has certain reference significance for the collaborative governance of complex regional systems.

关键词： System structure Efficiency measure Coupling mechanism Dynamic coordination

Photo-induced tunable luminescence from an aggregated amphiphilic ethylene-pyrene derivative in aqueous media

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Chinese Chemical Letters 2024年第6期35卷 303-306页

作者： Junying Zhang Ruochen Li Haihua wang Wenbing kang Xing-Dong Xu National Engineering Research Center for Colloidal Materials Key Laboratory of Special Functional Aggregated Materials of Ministry of EducationShandong Key Laboratory of Advanced Silicone Materials and TechnologySchool of Chemistry and Chemical EngineeringShandong UniversityJi’nan 250100China

An amphiphilic derivative with a large Stokes shift by introducing flexible hydrophilic long chains into a rigid ethylene-pyrene compound have been successfully *** alkylated compound exhibited a notable change in charge distribution,facilitating cation-π *** the process of amphiphilic self-assembly,the formation of highly ordered aggregates enabled effective photo-dimerization under 449 nm LED ***,this photo-responsive technology not only exhibited advanced multi-color emission effects,including white light emission but also exhibited environmentally friendly behavior in the aqueous phase.

关键词： Supramolecular chemistry Amphiphilic assembly Stimuli-responsive materials Tunable luminescence Pyrene derivative

Surface crack evolution patterns in freeze-thaw damage of fissured rock bodies

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Journal of Mountain Science 2024年第9期21卷 3094-3107页

作者： kang Zhiqiang wang Zhilei SHAO Luhang FENG Jiangjiang YAO Xulong College of Mining Engineering North China University of Science and TechnologyTangshan 063200China Green Intelligent Mining Technology Innovation Center of Hebei Province North China University of Science and TechnologyTangshan 063210China Luannan Macheng Mining Co. Ltd.Shougang Group Co.LtdLuannan CountyTangshan 063500China

To explore the effects of freeze‒thaw cycles on the mechanical properties and crack evolution of fissured sandstone,biaxial compression experiments were carried out on sandstone subjected to freeze‒thaw cycles to characterize the changes in the physical and mechanical properties of fissured sandstone caused by freeze‒thaw *** crack evolution and crack change process on the surface of the fissured sandstone were recorded and analysed in detail via digital image technology(DIC).Numerical simulation was used to reveal the expansion process and damage mode of fine-scale cracks under the action of freeze‒thaw cycles,and the simulation results were compared and analysed with the experimental data to verify the reliability of the numerical *** results show that the mass loss,porosity,peak stress and elastic modulus all increase with increasing number of freeze‒thaw *** an increase in the number of freeze‒thaw cycles,a substantial change in displacement occurs around the prefabricated cracks,and a stress concentration appears at the crack *** new cracks continue to sprout at the tips of the prefabricated cracks until the microcracks gradually penetrate into the main cracks,the displacement cloud becomes obviously discontinuous,and the contours of the displacement field in the crack fracture damage area simply intersect with the prefabricated cracks to form an obvious *** damage patterns of the fractured sandstone after freeze‒thaw cycles clearly differ,forming a symmetrical"L"-shaped damage pattern at zero freeze‒thaw cycles,a symmetrical"V"-shaped damage pattern at 10 freeze‒thaw cycles,and a"V"-shaped damage pattern at 20 freeze‒thaw *** 20 freeze‒thaw cycles,a"V"-shaped destruction pattern and"L"-shaped destruction pattern are formed;after 30 freeze‒thaw cycles,an"N"-shaped destruction pattern is *** shows that the failure mode of fractured sandstone gradually becomes more complicated with an increasing number of freeze‒t

关键词： Freeze‒thaw cycles Fissured sandstone Particle flow software Rock mechanics Crack extension pattern DIC technique

Advanced preparation and application of bimetallic materials in lithium-sulfur batteries:A review

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Journal of Energy Chemistry 2024年第1期88卷 469-512,I0011页

作者： yongbing Jin Nanping Deng Yanan Li Hao wang Meiling Zhang Weimin kang Bowen Cheng State Key Laboratory of Separation Membranes and Membrane Processes/National Center for International Joint Research on Separation Membranes School of Textile Science and EngineeringTiangong UniversityTianjin 300387China

Lithium-sulfur(Li-S)batteries are considered highly promising as next-generation energy storage systems due to high theoretical capacity(2600 Wh kg^(-1))and energy density(1675 mA h g^(-1))as well as the abundant natural reserves,low cost of elemental sulfur,and environmentally friendly ***,several challenges impede its commercialization including low conductivity of sulfur itself,the severe“shuttle effect”caused by lithium polysulfides(LiPSs)during charge–discharge processes,volume expansion effects and sluggish reaction *** a solution,polar metal particles and their compounds have been introduced as the main hosts for sulfur cathode due to their robust catalytic activity and adsorption capability,effectively suppressing the“shuttle effect”of Li *** alloys and their compounds with multi-functional properties exhibit remarkable electrochemical performance more readily when compared to single-metal ***-designed bimetallic materials demonstrate larger specific surface areas and richer active sites,enabling simultaneous high adsorption capability and strong catalytic *** synergistic effect of the“adsorption-catalysis”sites accelerates the adsorptiondiffusion-conversion process of Li PSs,ultimately achieving a long-lasting Li-S ***,the latest progress and performance of bimetallic materials in cathodes,separators,and interlayers of Li-S batteries are systematically ***,the principles and challenges of Li-S batteries are briefly ***,various mechanisms for suppressing“shuttle effects”of Li PSs are emphasized at the ***,the performance parameters of various bimetallic materials are comprehensively summarized,and some improvement strategies are proposed based on these ***,the future prospects of bimetallic materials are discussed,with the hope of providing profound insights for the rational design and manufacturing of high-performance bimetallic materia

关键词： Bimetallic materials Lithium-sulfur batteries Effectively suppress shuttle effect of LiPSs Significantly improve reaction kinetics Exceptionally long lifespan

Comprehensive applicability evaluation of four precipitation products at multiple spatiotemporal scales in Northwest China

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Journal of Arid Land 2024年第9期16卷 1232-1254页

作者： wang Xiangyu XU Min kang Shichang LI Xuemei HAN Haidong LI Xingdong School of Mathematics Lanzhou Jiaotong UniversityLanzhou 730070China Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China

Precipitation plays a crucial role in the water cycle of Northwest *** accurate precipitation data is crucial for regional water resource management,hydrological forecasting,flood control and drought ***,the applicability of multi-source precipitation products for long time series in Northwest China has not been thoroughly *** this study,precipitation data from 183 meteorological stations in Northwest China from 1979 to 2020 were selected to assess the regional applicability of four precipitation products(the fifth generation of European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis of the global climate(ERA5),Global Precipitation Climatology Centre(GPCC),Climatic Research Unit gridded Time Series Version 4.07(CRU TS v4.07,hereafter CRU),and Tropical Rainfall Measuring Mission(TRMM))based on the following statistical indicators:correlation coefficient,root mean square error(RMSE),relative bias(RB),mean absolute error(MAE),probability of detection(POD),false alarm ratio(FAR),and equitable threat score(ETS).The results showed that precipitation in Northwest China was generally high in the east and low in the west,and exhibited an increasing trend from 1979 to *** with the station observations,ERA5 showed a larger spatial distribution difference than the other *** overall overestimation of multi-year average precipitation was approximately 200.00 mm and the degree of overestimation increased with increasing precipitation *** multi-year average precipitation of GPCC and CRU was relatively close to that of station *** trend of annual precipitation of TRMM was overestimated in high-altitude regions and the eastern part of Lanzhou with more *** the monthly scale,GPCC performed well but underestimated precipitation in the Tarim Basin(RB=-4.11%),while ERA5 and TRMM exhibited poor accuracy in high-altitude ***5 had a large bias(RB≥120.00%)in winter months

关键词： precipitation products the fifth generation of European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis of the global climate(ERA5) Global Precipitation Climatology Centre(GPCC) Climatic Research Unit gridded Time Series(CRU TS) Tropical Rainfall Measuring Mission(TRMM) applicability evaluation Northwest China

Low Loss and Low EMI Noise Trench IGBT with Shallow Emitter Trench Controlled P-Type Dummy Region

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Chinese Journal of Electronics 2024年第2期33卷 326-335页

作者： Jinping ZHANG Xiaofeng LI Rongrong ZHU kang wang Bo ZHANG State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China (UESTC) Institute of Electronic and Information Engineering of UESTC in Guangdong

A novel trench insulated gate bipolar transistor（TIGBT） with a shallow emitter trench controlled P-type dummy region（STCP-TIGBT） is *** with the conventional TIGBT with floating P-type dummy region（CFP-TIGBT） and TIGBT with floating P-type dummy region and normally on hole path（HFPTIGBT）,the proposed STCP structure not only speeds up the extraction of excessive holes in the turn-off process but also reduces the Miller plateau charge(Qgc).Therefore,both the power loss and electromagnetic interference（EMI） noise are significantly *** results show that the Qgcof the proposed device is only 501 nC/cm2,which is reduced by 58.5% and 26.4% when compared to the CFP-TIGBT and HFP-TIGBT,*** same on-state voltage drop(Vceon) of 1.02 V,the turn-off loss(Eoff) of the proposed device is 13.49 mJ/cm2,which is 64.6%and 67.6% less than those of the CFP-TIGBT and HFP-TIGBT,***,the reverse recovery dVak/dt of the freewheeling diode at same turn-on loss(Eon) of 31.8 mJ/cm2for the proposed STCP-TIGBT is only 2.15 kV/μs,which is reduced by 91.3% and 57.2% when compared to 24.69 kV/μs and 5.02 kV/μs for the CFP-TIGBT and HFPTIGBT,*** reduced dV/dt significantly suppresses the electromagnetic interference noise generated by the proposed device.

关键词： Insulated gate bipolar transistors Electrodes Annealing Simulation Electromagnetic interference Noise Voltage

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600MW超临界机组滑参数停机探讨

华东电力 2008年第2期36卷 45-49页

作者：王永康华能上海石洞口第二电厂上海200941

滑参数停机能快速降低汽轮机转子和汽缸温度,缩短汽轮机检修前盘车运行时间,有利于尽快进行汽轮机本体检修。介绍了石洞口二厂600 MW超临界机组滑参数停机过程中锅炉压力、汽温、汽轮机转子应力、汽缸探针温度等参数控制的范围和操作要... 详细信息

滑参数停机能快速降低汽轮机转子和汽缸温度,缩短汽轮机检修前盘车运行时间,有利于尽快进行汽轮机本体检修。介绍了石洞口二厂600 MW超临界机组滑参数停机过程中锅炉压力、汽温、汽轮机转子应力、汽缸探针温度等参数控制的范围和操作要点。分析了滑参数停机过程中存在的问题及解决方法。

关键词：滑参数参数控制给水控制旁路控制

Understanding and unveiling the electro-chemo-mechanical behavior in solid-state batteries

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SusMat 2024年第2期4卷 75-88页

作者： Yunlei Zhong Xia Zhang yong Zhang Peng Jia Yuebin Xi Lixing kang Zhenjiang Yu Key Laboratory of Multifunctional Nanomaterials and Smart Systems Division of Advanced MaterialsSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhouChina Institute of Applied Materials Helmholtz Centre Berlin for Materials and EnergyBerlinGermany School of Electronic and Information Engineering Changshu Institute of TechnologyChangshuJiangsuChina State Key Laboratory of Biobased Material and Green Papermaking Qilu University of TechnologyJinanShandongChina

Solid-state batteries(SSBs)are attracting growing interest as long-lasting,thermally resilient,and high-safe energy storage *** an emerging area of battery chemistry,there are many issues with SSBs,including strongly reductive lithium anodes,oxidized cathodes(state of charge),the thermodynamic stability limits of solid-state electrolytes(SSEs),and the ubiquitous and critical *** this Review,we provided an overview of the main obstacles in the development of SSBs,such as the lithium anode|SSEs interface,the cathode|SSEs interface,lithium-ion transport in the SSEs,and the root origin of lithium intrusions,as well as the safety issues caused by the *** and overcoming these obstacles are crucial but also extremely challenging as the localized and buried nature of the intimate contact between electrode and SSEs makes direct detection *** reviewed advanced characterization techniques and discussed the complex ion/electron-transport mechanism that have been plaguing ***,we focused on studying and revealing the coupled electro-chemo-mechanical behavior occurring in the lithium anode,cathode,SSEs,and beyond.

关键词： advanced characterization techniques chemo-mechanical effects interface