检索结果-南通市图书馆

Strengthening strategy for high-performance friction stir lap welded joints based on 5083 Al alloy

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第11期31卷 2498-2507页

作者： Yujia shen Jijie wang Beibei wang Peng Xue Fengchao Liu Dingrui Ni Bolv xiao Zongyi Ma College of Material Science and Engineering Shenyang Aerospace UniversityShenyang 110136China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Binzhou Institute of Technology Shandong Key Laboratory of Advanced Aluminium Materials and TechnologyWeiqiao-UCAS Science and Technology ParkBinzhou 256606China Centre of Excellence for Advanced Materials Dongguan 523808China

During aircraft,ship,and automobile manufacturing,lap structures are frequently produced among Al alloy skins,wall panels,and *** occurrence of welding defects severely decreases mechanical properties during friction stir lap welding(FSLW).This study focuses on investigating the effects of rotation rate,multipass welding,and cooling methods on lap defect formation,microstructural evolution,and mechanical *** defects were eliminated by decreasing welding speed,applying two-pass FLSW with a small welding tool,and introducing additional water cooling,thus leading to a remarkable increase in effective sheet thickness and lap *** above strategy yielded defect-free joints with an ultrafine-grained microstructure and increased tensile shear force from 298 to 551 N/*** fracture behavior of FSLW joints was systematically studied,and a fracture factor of lap joints was proposed to predict their fracture *** reducing the rotation rate,using two-pass welding,and employing additional water cooling strategies,an enlarged,strengthened,and defect-free lap zone with refined ultrafine grains was achieved with a quality comparable to that of lap welds based on 7xxx Al ***,this study provides a valuable FSLW method for eliminating hook defects and improving joint performance.

关键词： friction stir lap welding defect control microstructure fracture mechanisms mechanical properties

On Minor Left Prime Factorization Problem for Multivariate Polynomial Matrices

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第3期37卷 1295-1307页

作者： LU Dong wang Dingkang xiao Fanghui School of Mathematics Southwest Jiaotong UniversityChengdu 610031China KLMM Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China MOE-LCSM School of Mathematics and StatisticsHunan Normal UniversityChangsha 410081China

A new necessary and sufficient condition for the existence of minor left prime factorizations of multivariate polynomial matrices without full row rank is *** key idea is to establish a relationship between a matrix and any of its full row rank *** on the new result,the authors propose an algorithm for factorizing matrices and have implemented it on the computer algebra system *** examples are given to illustrate the effectiveness of the algorithm,and experimental data shows that the algorithm is efficient.

关键词： Free modules Grobner bases minor left prime(MLP) multivariate polynomial matrices polynomial matrix factorizations

Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 562-573页

作者： Qianqian wang Zequn Yao Lijie Guo xiaodong shen College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology Group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions

Symmetry breaking of highly symmetrical nanoclusters for triggering highly optical activity

在线全文

学校读者我要写书评

暂无评论

Fundamental Research 2024年第1期4卷 63-68页

作者： xiao Wei Hao Li Honglei shen Chuanjun Zhou Shuxin wang Xi Kang Manzhou Zhu Department of Chemistry and Centre for Atomic Engineering of Advanced Materials Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationInstitutes of Physical Science and Information Technology and Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials.Anhui UniversityHefei 230601China

Developing new approaches to fulfill the enantioseparation of nanocluster racemates and construct cluster-based nanomaterials with optical activity remains highly desired in cluster science,because it is an essential prerequisite for fundamental research and extensive applications of these *** herein propose a strategy termed“active-site exposing and partly re-protecting”to trigger the symmetry breaking of highly symmetrical nanoclusters and to render cluster crystals optically *** vertex PPh_(3)of the symmetrical Ag_(29)(SSR)_(12)(PPh_(3))_(4)(SSR=1,3-benzenedithiol)nanocluster was firstly dissociated in the presence of counterions with large steric hindrance,and then the exposed Ag active sites of the obtained Ag_(29)(SSR)_(12)nanocluster were partly re-protected by Ag^(+),yielding an Ag_(29)(SSR)_(12)-Ag_(2)nanocluster with a symmetry-breaking ***_(29)(SSR)_(12)-Ag_(2)followed a chiral crystallization mode,and its crystal displayed strong optical activity,derived from CD and CPL ***,this work presents a new approach(i.e.,active-site exposing and partly re-protecting)for the symmetry breaking of highly symmetrical nanoclusters,the enantioseparation of nanocluster racemates,and the achievement of highly optical activity.

关键词： Atomically precise nanocluster Symmetry breaking Enantioseparation Circularly polarized luminescent Photoluminescence

Design method and experimental study of a cathode tool with an extremely high leveling ratio for electrochemical machining of blisk

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第4期37卷 593-608页

作者： Moqi shen Jia LIU Jingtao wang Di ZHU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To obtain final parts with the desired dimensional accuracy and repeatability via electrochemical machining(ECM), the machining process must enter an ECM balanced state. However,for the ECM processing of blisk, a key component of aerospace engines, the surface of the blade blank often has an uneven allowance distribution due to the narrow passage of the cascade. It is difficult to remedy this issue in subsequent processing steps, which is necessary to ensure the dimensional accuracy and repeatability of the final blade profile. To solve this problem, electrolytic machining must be preceded by electrolytic shaping, which requires cathode tools with large leveling ratios to quickly homogenize the blank surface of the blade. In this study, to obtain a cathode tool with an extremely high leveling ratio, a design method based on the variation in the electrode gap in the non-equilibrium electrolytic state is proposed, and a dissolution model based on the nonequilibrium state is established. In this design method, the allowance on the blank to be machined is first divided into many discrete allowances with the normal direction. The initial machining clearance, feed rate, and total machining time are then calculated using classical ECM equilibrium state theory based on the maximum allowance. Meanwhile, the point coordinates of the cathode tool at maximum allowance can be determined. The non-equilibrium model can then be used to calculate the relative coordinate positions corresponding to the remaining discrete allowances. Finally, the entire cathode tool profile is designed. Simulations, fundamental experiments, and blisk unit workpiece experiments were carried out to validate the design approach. In the simulated processing of the plane workpiece, the leveling ratio of the cathode tool designed by the proposed method(0.77)was 83% higher than that of the cathode tool designed using the traditional method. The simulation results were confirmed by processing experiments. In t

关键词： Electrochemical machining(ECM) Non-equilibrium machining Large leveling ratios Cathode design Finite element simulation Blisk

Recent progress of cobalt-based electrocatalysts for water splitting: Electron modulation, surface reconstitution, and applications

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第4期17卷 2234-2269页

作者： Zhijian Liang Di shen Lei wang Honggang Fu Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People’s Republic of ChinaHeilongjiang UniversityHarbin 150080China

Electrocatalytic water splitting is an essential and effective means to produce green hydrogen energy structures,so it is necessary to develop non-precious metal catalysts to replace precious ***-based catalysts present effective alternatives due to the diverse valence states,adjustable electronic structures,and plentiful *** this review,the catalytic mechanisms of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)for electrocatalytic water splitting are ***,the synthesis strategies of various cobalt-based catalysts are systematically summarized,followed by the relationships between the structure and performance ***,the effects of d-band center and spin regulation for cobalt-based catalysts are also ***,the dynamic electronic and structural devolution of cobalt-based catalysts are elucidated by combining a series of in-situ ***,we highlight the challenges and future developed directions of cobalt-based catalysts for electrocatalytic water splitting.

关键词： cobalt-based electrocatalysts water splitting electron modulation surface reconfiguration

Real-Time 3D Ultrasound Imaging System Based on a Hybrid Reconstruction Algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 245-255页

作者： Yifei LYU Yu shen Mingbo ZHANG Junchen wang School of Mechanical Engineering and Automation Beihang University The First Medical Center General Hospital of Chinese PLA

As a safe and convenient imaging technology in clinical routine diagnosis, ultrasound imaging can provide real-time 2D images of internal tissues and organs. To realize real-time 3D image reconstruction, pixel nearest neighbor interpolation(PNN) reconstruction algorithm and Bezier interpolation algorithm are combined into a hybrid reconstruction algorithm. On this basis, a real-time interactive 3D ultrasound imaging system is *** temporal calibration and spatial calibration, the six degrees of freedom poses of 2D ultrasound images can be accurately collected. The 3D volume reconstructed by the proposed 3D reconstruction algorithm is visualized by volume rendering. A multi-thread software system allows parallel operation of data acquisition, 3D reconstruction,volume visualization and other functions. 3D imaging experiments on a 3D printing femur model, a neck phantom and the neck of human volunteers were performed for systematic evaluation. When the reconstruction voxel size was set to be(0.53 mm3, 1.03 mm3, 1.53 mm3), the reconstruction errors of the femur and trachea model were respectively(0.23 mm, 0.31 mm, 0.56 mm) and(0.62 mm, 0.88 mm, 1.41 mm). Clinical feasibility was demonstrated by application of the 3D ultrasound imaging on the neck of human volunteers.

关键词： Interpolation Three-dimensional displays Ultrasonic imaging Imaging Data visualization Reconstruction algorithms Real-time systems

Progress on the glassy-crystal laminates:From design,microstructure to deformation and future solutions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第5期172卷 113-144页

作者： Yu Chen Ronggao Cui Jun shen Gang wang College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Motor Design Business Weichai New Energy Technology Co.Ltd.Weifang 261061China Guangdong Key Laboratory of Electromagnetic Control and Intelligent Robots Shenzhen UniversityShenzhen 518060China Laboratory for Microstructures Institute of MaterialsShanghai UniversityShanghai 200444China

The development of new design strategies to create innovative structural materials,refine existing ones,and achieves compatible combinations of strength and plasticity remains a worldwide *** alloys,such as shape memory alloys(SMAs),bulk metallic glasses(BMGs),high entropy alloys(HEAs),and heterogeneous pure metals such as Cu,have excellent mechanical responses,but they still fall short of meeting all the requirements of structural materials due to specific flaws,such as lack of tensile de-formation for BMGs and low yielding strength for *** address these shortcomings,proposals such as integrating glassy matrices and crystallized alloys,such as HEAs/SMAs,have been ***,these solutions have unresolved issues,such as the challenging control of B2 phase formation in BMG ***,glass-crystal(A/C)laminated alloys with alternating layers have been reported to exhibit improved mechanical properties and activated work-hardening behaviors,but they still face press-ing issues such as bonding interfaces and unknown deformation *** review focuses on design routes such as the selection of alloy components and processing techniques,exploration of micro-structural evolution and deformation modes with an increase in strain,and future solutions to address pressing and unsolved *** prominent advantages include diversified deformation mechanisms,such as deformation twinning,martensitic phase transformation,and precipitation hardening,as well as tuned interactive reactions of shear bands(SBs)near the A/C ***,this review provides a promising pathway to design and develop structural materials in the materials field community.

关键词： Glassy-crystal laminates Bulk metallic glasses High entropy alloys Shape memory alloys Microstructure Deformation mechanisms Future solutions

Harmonic Transfer Function Based Single-input Single-output Impedance Modeling of LCC-HVDC Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1327-1332页

作者： Yang wang Fei Xia Ying wang Xianyong xiao College of Electrical Engineering Sichuan UniversityChengdu 610065China

This study presents a harmonic transfer function(HTF)based single-input single-output(SISO)impedance modeling *** method converts an HTF from phase domain to sequence domain and then transforms it into an SISO impedance while preserving the frequency coupling information of different sequences and different *** of this method to a line-commutated converter based high-voltage direct current(LCC-HVDC)system are *** results demonstrate the accuracy of the derived SISO impedance,and a truncation-order selection is *** case study shows that the proposed method facilitates simpler impedance measurements and associated stability analysis.

关键词： Line-commutated converter based high-voltage direct current(LCC-HVDC) harmonic transfer function(HTF) single-input single-output(SISO)impedance frequency coupling