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Experimental investigation of junction growth of rough contacts using X-ray computed tomography

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Friction 2024年第11期12卷 2519-2531页

作者： Runliang wang jianhua LIU Bo LIU Duo jia Xiaoyu DING School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China AECC Shenyang Engine Research Institution Shenyang 110000China

The real contact area(RCA)of randomly rough contacts has received a great deal of attention because it correlates strongly with friction,lubrication,sealing,and *** have revealed that the RCA associated with deterministic normal squeezing loads increases when tangential loads are also applied,in a phenomenon called junction ***,experimental investigations of the junction growth of randomly rough contacts are ***,we used X-ray computed tomography(CT)to measure junction growth when two aluminum alloy surfaces were in contact.A high-resolution experimental setup was used to apply loads and observe contact behaviors at a resolution of 4μ*** RCA and average contact gaps were computed using a three-dimensional(3D)geometric model constructed from gray CT images using the Otsu thresholding *** results showed that the RCA increased as the normal load *** RCA increased by 22.67%after a tangential load was applied(junction growth),and the average gap decreased by 14.01%after a tangential load was ***,X-ray CT accurately measured the junction growth as a novel quantitative method.

关键词： three-dimensional(3D)contact analyses real contact area(RCA),junction growth X-ray computed tomography(CT) assembly interfaces

Recent applications of macrocycles in supramolecular catalysis

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Chinese Chemical Letters 2024年第4期35卷 132-141页

作者： Conghui wang Lei Xu Zhenhua jia Teck-Peng Loh College of Advanced Interdisciplinary Science and Technology Henan University of TechnologyZhengzhou 450001China Division of Chemistry and Biological Chemistry School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore Institute of Advanced Synthesis School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China

Numerous supramolecular macrocycles have been utilized for developing catalysts by exploiting their specific molecular recognition and ability to form inclusion complexes through noncovalent interactions. The cyclic structure and modified functional groups of these macrocycles can influence substrate and transition state stability, as well as reaction selectivity. The inner cavities of these macrocycles are particularly beneficial, as they enable substrates to adopt preorganized arrangements and serve as versatile platforms for highly efficient supramolecular catalytic systems. This minireview provides an overview of recent advancements in supramolecular catalysis using various macrocycles, such as crown ethers, cyclodextrins,calixarenes, pillararenes, cucurbiturils, and other novel macrocycles.

关键词： Supramolecular catalysis Macrocycle Host-guest interactions Confinement Selectivity

Dynamic simulation of GEH-IES with distributed parameter characteristics for hydrogen-blending transportation

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Frontiers in Energy 2024年第4期18卷 506-524页

作者： Dengji ZHOU jiarui HAO wang XIAO Chen wang Chongyuan SHUI Xingyun jia Siyun YAN Key Laboratory of Power Machinery and Engineering of the ministry of Education Shanghai Jiao Tong UniversityShanghai 200240China Sichuan Research Institute Shanghai Jiao Tong UniversityChengdu 610042China West Pipeline Company National Petroleum and Natural Gas Pipe Network Group Co.Ltd.Urumqi 830012China Institute of Intelligent Manufacturing Modern Industry Xinjiang UniversityUrumqi 830046China

For the purpose of environment protecting and energy saving,renewable energy has been distributed into the power grid in a considerable ***,the consuming capacity of the power grid for renewable energy is relatively *** an effective way to absorb the excessive renewable energy,the power to gas(P2G)technology is able to convert excessive renewable energy into ***-blending natural gas pipeline is an efficient approach for hydrogen ***,hydrogen-blending natural gas complicates the whole integrated energy system(IES),making it more problematic to cope with the equipment failure,demand response and dynamic ***,dynamic simulation of distribution parameters of gas-electricity-hydrogen(GEH)energy system,especially for hydrogen concentration,still remains a *** dynamics of hydrogen-blending IES is *** tackle the issue,an iterative solving framework of the GEH-IES and a cell segment-based method for hydrogen mixing ratio distribution are proposed in this *** typical numerical cases studying the conditions under which renewables fluctuate and generators fail are conducted on a real-word *** results show that hydrogen blending timely and spatially influences the flow parameters,of which the hydrogen mixing ratio and gas pressure loss along the gas pipeline are negatively correlated and the response to hydrogen mixing ratio is ***,the hydrogen-blending amount and position also have a significant impact on the performance of the compressor.

关键词： gas-electricity IES dynamic simulation hydrogen blending power to gas(P2G) renewable energy

Recent Advances in Photochemical/Electrochemical Carboxylation of Olefins with CO_(2)

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Chinese Journal of Chemistry 2024年第18期42卷 2249-2266页

作者： Qian wang Yanwei wang min Liu Ganghui Chu Youai Qiu Xinjiang Laboratory of Native Medicinal and Edible Plant Resources Chemistry College of Chemistry and Environmental ScienceKashiUniversityKashiXinjiang844000China state Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Centerfor New Organic MatterCollege of Chemistry NankaiUniversity94WeijinRoadTianjin300071China

CO_(2) is an abundant,nontoxic,and renewable C1 feedstock in synthetic *** carboxylation of readily available olefins incorporating CO_(2) is regarded as a promising strategy to access high value-added carboxylic acids as well as CO_(2) ***,due to the thermodynamic stability and kinetic inertness of CO_(2) and the difficulty in controlling the regioselectivity,the carboxylation of olefins with CO_(2) still remains ***-type functionalization with olefins represented a powerful protocol and enabled the development of novel transformations in this *** recently,the advance of new technology,such as photoredox catalysis and the renaissance of electrochemistry in organic synthesis,offered access to unique chemical reactivities of radical precursors and provided new solutions to the functionalization of olefins.

关键词： CO_(2) Carboxylation Olefins Photocatalysis Electrocatalysis Radical Reduction Difunctionalization

Synergistic effects of multiscale TiC and dual-phase structure on tensile properties of particle-reinforced steel

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Journal of Iron and Steel Research International 2024年第5期31卷 1232-1245页

作者： Ye jia Xiang-tao Deng Qi wang Cheng-ru Li Hao Wu Zhao-dong wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina

The conventional melting methods were used to obtain in situ TiC particle-reinforced dual-phase steel,followed by hot rolling and heat treatment *** aim was to investigate the effect of TiC particles on the fracture behavior of dual-phase steel at different annealing temperatures,by analyzing the microstructure and tensile behavior of the multiscale TiC particle-reinforced dual-phase *** results showed that TiC particles precipitated in the as-cast microstructure of dual-phase steel were distributed along the grain *** hot rolling,the grain boundary-like morphology of the micron-sized TiC particles was disrupted,and the particles became more refined and evenly distributed in the *** tensile tests revealed that the strength of the TiC particle-reinforced dual-phase steel increased with increasing martensite content,while the elongation *** results were similar to those of conventional *** addition of 1 vol.%multiscale TiC particles improved the strength of the dual-phase steel but did not affect elongation of the *** and holes were primarily concentrated around the TiC particles rather than at the interface of martensite and *** main causes of crack sprouting were TiC particle interface cracking and TiC particle internal ***,the study demonstrated the potential of multiscale TiC particle-reinforced dual-phase steel as a strong and tough *** refined distribution of TiC particles in the matrix improved the strength of the material without compromising its *** results also highlighted the importance of careful selection of reinforcement particles to avoid detrimental effects on the fracture behavior of the material.

关键词： TiC particle Dual-phase structure TiC-reinforced dual-phase steel Tension Fracture behavior

Density-Functional Theories for Polyelectrolyte Systems

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Chinese Journal of Polymer Science 2024年第9期42卷 1302-1312,I0006页

作者： jia-Wei Zhang Yu-Hang Zhang Bao-Hui Li Qiang wang School of Physics Nankai UniversityTianjin90001China Department of Chemical and Biological Engineering Colorado State University1370 Campus DeliveryFort CollinsCO80523-1370USA

Polymer density-functional theories(PDFTs)have distinct advantages in the study of polyelectrolyte(PE)systems over experiments and molecular *** we give an introductory review of some PDFTs recently developed for PE *** start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory(SCFT),then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs,including those due to the excluded-volume interaction and chain connectivity of uncharged polymers,the electrostatic correlations of small ions,and the chain correlations in *** also list some applications of PDFTs for PE systems,and finally give some perspectives on future *** hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.

关键词： Polymer density-functional theories Polyelectrolytes Correlations

Preparation and characterization of high-reactivity explosive-based nano-boron microspheres

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Particuology 2024年第10期93卷 125-136页

作者： Chen Dong Yi wang Kanghui jia Dan Song Xiaolan Song Chongwei An School of Materials Science and Engineering North University of ChinaTaiyuan030051China Jinxi Group Shanxi jiangyang Chemical Co. Ltd.Taiyuan030051China China Ordnance Institute of Science and Technology Beijing100089China School of Environment and Safety Engineering North University of ChinaTaiyuan030051China

Boron nanoparticles,with their remarkably high gravimetric and volumetric calorific values,emerge as the most promising fuel in energetic ***,challenges such as susceptibility to oxidation,high ignition temperature,and low combustion efficiency have constrained their further *** this study,we fabricated high explosives based nano-boron microspheres with uniform size using the electrostatic spray method,in which the boron nanoparticles and high explosives(CL-20 or PETN)are closely bonded together by fluorinated polymer(F2602)and evenly *** results indicated that the microspheres exhibited high sphericity and showed an enhanced antioxidant *** addition of high-energy explosives not only reduced the thermal oxidation temperature of nano-boron powder within the microspheres but also significantly enhanced the pressurization ***,the microspheres with added high-energy explosives released more energy during the combustion *** to physically mixed samples,electrostatically sprayed microspheres with a uniform microstructure still exhibited higher ***,the design and synthesis of microspheres with controllable structures using the electrostatic spray method show promising application prospects.

关键词： Nano-boron CL-20 PETN Electrospraying Ignition and combustion

Research progress on electronic and active site engineering of cobalt‐based electrocatalysts for oxygen evolution reaction

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Carbon Energy 2024年第8期6卷 134-165页

作者： Chuansheng He Linlin Yang jia wang Tingting wang jian Ju Yizhong Lu Wei Chen School of Materials Science and Engineering University of JinanJinanChina Catalonia Energy Research Institute—IREC Sant Adriàde BesòsBarcelonaSpain Department of Electronic and Biomedical Engineering University of BarcelonaBarcelonaSpain Graduate School of Integrated Sciences for Life Hiroshima UniversityHigashi‐HiroshimaHiroshimaJapan Wenzhou Institute University of Chinese Academy of SciencesWenzhouChina Oujiang Lab WenzhouChina School of Chemistry and Pharmaceutical Science Guangxi Normal UniversityGuilinChina

Electrocatalytic water splitting has been identified as a potential candidate for producing clean hydrogen energy with zero carbon ***,the sluggish kinetics of oxygen evolution reaction on the anode side of the watersplitting device significantly hinders its practical ***,the efficiency of oxygen evolution processes depends greatly on the availability of cost‐effective catalysts with high activity and *** recent years,extensive theoretical and experimental studies have demonstrated that cobalt(Co)‐based nanomaterials,especially low‐dimensional Co‐based nanomaterials with a huge specific surface area and abundant unsaturated active sites,have emerged as versatile electrocatalysts for oxygen evolution reactions,and thus,great progress has been made in the rational design and synthesis of Co‐based nanomaterials for electrocatalytic oxygen evolution *** the remarkable progress in this area,in this timely review,we highlight the most recent developments in Co‐based nanomaterials relating to their dimensional control,defect regulation(conductivity),electronic structure regulation,and so ***,a brief conclusion about recent progress achieved in oxygen evolution on Co‐based nanomaterials,as well as an outlook on future research challenges,is given.

关键词： Co‐based nanomaterial dimension regulation electronic structure and active site oxygen evolution reaction

Moderate Deviations for Parameter Estimation in the Fractional Ornstein–Uhlenbeck Processes with Periodic Mean

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1308-1324页

作者： Hui jiaNG Shi min LI Wei Gang wang School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China The People's Bank of China Operations Ofice of Nanjing Branch Nanjing 210016P.R.China School of Statistics and Mathematics Zhejiang Gongshang UniversityHangzhou 310018P.R.China

In this paper,we study the asymptotic properties for the drift parameter estimators in the fractional Ornstein-Uhlenbeck process with periodic mean function and long range *** Cremér-type moderate deviations,as well ... 详细信息

关键词： Cramér-type moderate deviation fractional Ornstein-Uhlenbeck process parameter estimation multiple Wiener-Ito integrals