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Mechanism and application of mechanical property improvements in engineering materials by pulsed magnetic treatment:A review

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Friction 2024年第10期12卷 2139-2166页

作者： Zhipeng cai Chengkai QIAN xu ZHANG Ning DAI Yao WU wen JI State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin 300304China

Pulsed magnetic treatment(PMT)has been adopted as an effective strengthening method for engineering materials and components in recent years,and the development of its application depends on the comprehensive understanding of the nature of *** deep mechanism was thought initially to be the magnetostrictive effect,while further investigation found that the magnetic field could lead to the change of the defect states in the crystal,which is called the magnetoplastic *** to the complexity of the engineering materials,manifestations of the magnetoplastic effect become more diverse,and they were reviewed in the form of microstructure homogenization and interfacial ***,the mechanism of the magnetoplastic effect was discussed,focusing on the changes in the spin states under the external magnetic *** modifications could also alter material performances,especially the residual stress,plasticity,and fatigue ***,PMT with specific parameters can be utilized to obtain an ideal combination of microstructure,residual stress,and mechanical properties for better service performance of different mechanical parts,and its applications on machining tools and bearings are perfect *** work reviews the effect of PMT on the microstructure and properties of different materials and the mechanism,and it also summarizes the fundamental applications of PMT on essential mechanical parts.

关键词： pulsed magnetic treatment wear resistance microstructure modifications mechanical properties magnetoplastic effect

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One-step construction of strongly coupled Co_(3)V_(2)O_(8)/Co_(3)O_(4)/MXene heterostructure via in-situ Co-F bonds for high performance all-solid-state asymmetric supercapacitors

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Rare Metals 2024年第2期43卷 682-691页

作者： Ji Zhou Bin-Bin Liu Hu Zheng wen-Qing Ma Qian Li cai-Xia xu Institute for Advanced Interdisciplinary Research(iAIR) Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongSchool of Chemistry and Chemical EngineeringUniversity of JinanJinan250022China

Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal *** interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) *** from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 *** work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.

关键词： Ti_(3)C_(2)T_(x) Co_(3)V_(2)O_(8)/Co_(3)O_(4) Heterostructure Cathode Supercapacitor

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Microstructure and mechanical properties of CuAgZn/GH909 diffusion bonded joint fabricated by hot isostatic pressing

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Transactions of Nonferrous Metals Society of China 2021年第2期31卷 475-484页

作者： Yi XIAO Li-hui LANG wen-cai xu School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China

The hot isostatic pressing-diffusion bonding(HIP-DB)was proposed to achieve the joining of CuAgZn and GH909 directly without an *** microstructure of joint was characterized by scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and X-ray diffraction(XRD).The microhardness and shear strength were tested to investigate the mechanical properties of *** results showed that the interface was complete,and the joint was compact,uniform and free of unbonded *** maximum microhardness of joint was HV 443,higher than that of two base alloys,and the average shear strength of joint reached 172 *** is concluded that a good metallurgical bonding between CuAgZn and GH909 can be obtained by HIP-DB with the process parameters of 700℃,150 MPa and 3 h.

关键词： CuAgZn alloy GH909 superalloy diffusion bonding hot isostatic pressing

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Methanol steam reforming for hydrogen production driven by an atomically precise Cu catalyst

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Green Energy & Environment 2024年第7期9卷 1079-1084页

作者： Weigang Hu Haoqi Liu Yuankun Zhang Jiawei Ji Guangjun Li Xiao cai xu Liu wen Wu xu Weiping Ding Yan Zhu School of Chemistry and Chemical Engineering Nanjing UniversityNanjing210093China School of Physical Science and Technology Ningbo UniversityNingbo315211China

Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research,however it remains elusive whether molecular-like metal clusters with excitonic behavior can be used as light-harvesting materials in solar energy utilization such as photocatalytic methanol steam *** this work,we report an atomically precise Cu_(13)cluster protected by dual ligands of thiolate and phosphine that can be viewed as the assembly of one top Cu atom and three Cu_(4)*** Cu_(13)H_(10)(SR)_(3)(PR’_(3))_(7)(SR=2,4-dichlorobenzenethiol,PR’_(3)=P(4-FC_(6)H_(4))_(3))cluster can give rise to highly efficient light-driven activity for methanol steam reforming toward H_(2)production.

关键词： Nanocluster Photocatalysis Methanol steam reforming Atomically precise Copper catalyst

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Design and performance evaluation of a large field-of-view dual-particle time-encoded imager based on a depth-of-interaction detector

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Nuclear Science and Techniques 2024年第4期35卷 1-14页

作者： Dong Zhao xu-wen Liang Ping-Kun cai Wei Cheng wen-Bao Jia Da-Qian Hei Qing Shan Yong-Sheng Ling Chao Shi Department of Nuclear Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions Suzhou 215000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

Time-encoded imaging is useful for identifying potential special nuclear materials and other radioactive sources at a *** this study,a large field-of-view time-encoded imager was developed for gamma-ray and neutron source hotspot imaging based on a depth-of-interaction(DOI)*** imager primarily consists of a DOI detector system and a rotary dual-layer cylindrical coded *** EJ276 plastic scintillator coupled with two SiPMs was designed as the DOI detector to increase the field of view and improve the imager *** difference in signal time at both ends and the log of the signal amplitude ratio were used to calculate the interaction position *** position resolution of the DOI detector was calibrated using a collimated Cs-137 source,and the full width at half maximum of the reconstruction position of the Gaussian fitting curve was approximately 4.4 *** DOI detector can be arbitrarily divided into several units to independently reconstruct the source distribution *** unit length was optimized via Am-Be source-location experiments.A multidetector filtering method is proposed for image *** method can effectively reduce image noise caused by poor DOI detector position *** vertical field of view of the imager was(-55°,55°)when the detector was placed in the center of the coded mask.A DT neutron source at 20 m standoff could be located within 2400 s with an angular resolution of 3.5°.

关键词： Time-encoded imager Depth-of-interaction detector Dual-particle imaging Hotspot imaging

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Highly Conductive Ag/pCF/MVQ Composite Rubber for Efficient Electromagnetic Interference Shielding

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Chinese Journal of Polymer Science 2024年第6期42卷 864-873页

作者： Yang Chen Xiao-Ming Shao Liang He Yi-Nuo xu Qi-Yuan Yao Ding Feng wen-cai Wang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials Beijing University of Chemical TechnologyBeijing100029China Sino-german School of Engineering Qingdao University of Science and TechnologyQingdao266400China

In this study,flexible and highly conductive composite rubber at low filler content was successfully prepared through polydopamine-assisted electroless silver plating plus mechanical ***,carbon fibers(CF)were activated by polydopamine(PDA)to improve the surface activity by self-polymerization ***,because of the metal chelating ability of PDA,silver layer was firmly deposited on the surface of CF through a facile electroless silver plating ***,flexible silver-plated carbon fibers(Ag/pCF)silicone rubber composites prepared by mechanical *** using X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD),the chemical composition and crystal structure of Ag/pCF were examined,and scanning electron microscopy(SEM)was used to assess the surface morphology of the Ag/*** results showed that a uniform and dense silver layer was formed on the surface of the CF,and the conductivity of the Ag/pCF could reach 7885 S/*** was noteworthy that the composite rubber filled with only 45 phr Ag/pCF had a high electromagnetic interference shielding effectiveness(100 dB)due to the low density and high aspect ratio of Ag/*** composite rubber has excellent potential for application in the field of electromagnetic interference shielding.

关键词： Carbon fibers Polydopamine Electroless plating Silver Electromagnetic interference shielding

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CFD investigation of structural effects of internal gas intake on powder conveying performance in fuel supply systems for aerospace engines

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Particuology 2024年第9期92卷 140-154页

作者： Guanlong Ren Haijun Sun Fangjun Chen wen Shen Yunzhen cai Yihua xu Henrik Ström Bilainu Oboirien Qingang Xiong School of Aircraft Engineering Nanchang Hangkong UniversityNanchang330063China Engineering Research Center of Aero-engine Technology for General Aviation Ministry of EducationNanchang330063China State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou510640China Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGöteborg41296Sweden Department of Chemical Engineering University of JohannesburgJohannesburg17011South Africa

Optimal design of gas intake in powder fuel supply systems is crucial for performance of aerospace *** is little research on the impact of intake structure on powder conveying *** novel internal intakes were proposed,which are spherical,cube-shaped,and *** validation,CFD simulations demonstrate that fluctuation of mass flow rate of powders in the dome-shaped intake is reduced by about 73.3%compared with the annular external *** trends of phase velocities are similar for the spherical and cube-shaped intakes,while those are similar for the annular external and dome-shaped internal *** of area of gas zone for the annular external and spherical internal intakes is larger than that for the cube-shaped and dome-shaped internal *** and relative pressure drop in the fluidization chamber have a stable stage,and fluctuation of relative pressure drop is small when dome-shaped internal intake is used.

关键词： Powder supply system Intake structure Dense gas-solid flow Two-fluid model Powder fluidization Pressure drop

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Combined effects of ultrasonic vibration and FeCoNiCrCu coating on interfacial microstructure and mechanical properties of Al/Mg bimetal by compound casting

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China Foundry 2024年第5期21卷 588-598页

作者： Yuan-cai xu wen-ming Jiang Qing-qing Li Ling-hui Yu Xiao-peng Yu Zi-tian Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

In this work,a new treatment method combining ultrasonic vibration with FeCoNiCrCu high entropy alloy(HEA)coating was used to prepared Al/Mg bimetal through the lost foam compound *** effects of composite treatment involving ultrasonic vibration and HEA coating on interfacial microstructure and mechanical properties of Al/Mg bimetal were *** demonstrate that the interface thickness of the Al/Mg bimetal with composite treatment significantly decreases to only 26.99%of the thickness observed in the untreated Al/Mg *** HEA coating hinders the diffusion between Al and Mg,resulting the significant reduction in Al/Mg intermetallic compounds in the *** Al/Mg bimetal interface with composite treatment is composed of Al_(3)Mg_(2)and Mg_(2)Si/AlxFeCoNiCrCu+FeCoNiCrCu/δ-Mg+Al_(12)Mg_(17)eutectic *** interface resulting from the composite treatment has a lower hardness than that without *** acoustic cavitation and acoustic streaming effects generated by ultrasonic vibration promote the diffusion of Al elements within the HEA coating,resulting in a significant improvement in the metallurgical bonding quality on the Mg *** fracture position shifts from the Mg side of the Al/Mg bimetal only with HEA coating to the Al side with composite *** shear strength of the Al/Mg bimetal increases from 32.16 MPa without treatment to 63.44 MPa with ultrasonic vibration and HEA coating,increasing by 97.26%.

关键词： ultrasonic vibration FeCoNiCrCu HEA coating Al/Mg bimetal interfacial microstructure shear strength compound casting

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Exceptional Early Jurassic fossils with leathery eggs shed light on dinosaur reproductive biology

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National Science Review 2024年第6期11卷 146-158页

作者： Fenglu Han Yilun Yu Shukang Zhang Rong Zeng Xinjin Wang Huiyang cai Tianzhuang Wu Yingfeng wen Sifu cai Chun Li Rui Wu Qi Zhao Xing xu School of Earth Sciences China University of Geosciences (Wuhan) Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences University of Chinese Academy of Sciences Guizhou Provincial Museum Guizhou Provincial Institute of Cultural Relics and Archaeology Pingba Institute of Cultural Relics Administration Centre for Vertebrate Evolutionary Biology Yunnan University

Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly,these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves.

关键词： dinosaur sauropodomorph Jurassic embryo egg evolution reproductive behavior

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Automatic Requirement Dependency Extraction Based on Integrated Active Learning Strategies

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Machine Intelligence Research 2024年第5期21卷 993-1010页

作者： Hui Guan Guorong cai Hang xu Department of Computer Science and Technology Shenyang University of Chemical TechnologyShenyang110142China Key Laboratory of Industrial Intelligence Technology on Chemical Process Shenyang110142China

Since requirement dependency extraction is a cognitively challenging and error-prone task,this paper proposes an automatic requirement dependency extraction method based on integrated active learning *** this paper,the coefficient of variation method was used to determine the corresponding weight of the impact factors from three different angles:uncertainty probability,text similarity difference degree and active learning variant prediction divergence *** combining the three factors with the proposed calculation formula to measure the information value of dependency pairs,the top K dependency pairs with the highest comprehensive evaluation value are selected as the optimal *** the optimal samples are continuously added into the initial training set,the performance of the active learning model using different dependency features for requirement dependency extraction is rapidly ***,compared with other active learning strategies,a higher evaluation measure of requirement dependency extraction can be achieved by using the same number of ***,the proposed method using the PV-DM dependency feature improves the weight-F1 by 2.71%,the weight-recall by 2.45%,and the weight-precision by 2.64%in comparison with other strategies,saving approximately 46%of the labelled data compared with the machine learning approach.

关键词： Requirement dependency dependency extraction dependency features integrated active learning strategies coefficient of variation

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