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Quality assessment of friction-stir-welded aluminum alloy welds via three-dimensional force signals

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Advances in Manufacturing 2024年第1期12卷 61-75页

作者： ji-Hong Dong Yi-Ming Huang jia-Lei Zhu Wei Guan xu-Kai Ren Huan-Wei Yu Lei Cui Beijing Institute of Petrochemical Technology Beijing102617People’s Republic of China Beijing Academy of Safety Engineering and Technology Beijing102617People’s Republic of China AVIC Manufacturing Technology Institute Beijing100024People’s Republic of China Tianjin Key Laboratory of Advanced Joining Technology School of Materials Science and EngineeringTianjin UniversityTianjin300350People’s Republic of China Shaoxing Special Equipment Testing Institute Shaoxing Key Laboratory of Special Equipment Intelligent Testing and EvaluationShaoxing312071ZhejiangPeople’s Republic of China

An online detection technology must be developed for realizing the real-time control of friction stir *** this study,the three-dimensional force exerted on a material during friction stir welding was collected synchronously and the relationship between the forces and welding quality was *** results indicated that the fluctuation period of the traverse force was equal to that of the lateral force during the stable welding *** phase difference between two horizontal forces wasπ/*** values of the horizontal forces increased with welding speed,whereas their amplitudes remained the *** proposed force model showed that the traverse and lateral forces conformed to an elliptical curve,and this result was consistent with the behavior of the measured *** variational mode decomposition was used to process the plunge *** intrinsic mode function that represented the real fluctuation in the plunge force varied at the same frequency as the spindle rotational *** tunnel defects occurred,the fluctuation period features were consistent with those obtained during normal welding,whereas the ratio parameter defined in this study increased significantly.

关键词： Friction stir welding(FSW) Three-dimensional force model Variational mode decomposition Tunnel defect

Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： ji-peng Li De-gao Qiao jian Li Xiao-yang Luo Peng Peng Xian-tao Yan xu-dong Zhang Gansu jiu Steel Group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

Nitrogen-doped titanium dioxide/schwertmannite nanocomposites as heterogeneous photo-Fenton catalysts with enhanced efficiency for the degradation of bisphenol A

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Journal of Environmental Sciences 2024年第9期143卷 1-11页

作者： Xing-Xing Qiao Yu-Hang xu Xiang-ji Liu Sai-Le Chen Zhou Zhong Ya-Feng Li jian Lü Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Potential health risks related to environmental endocrine disruptors(EEDs)have aroused research hotspots at the forefront of water treatment ***,nitrogen-doped titanium dioxide/schwertmannite nanocomposites(N-TiO_(2)/SCH)have been successfully developed as heterogeneous catalysts for the degradation of typical EEDs via photo-Fenton *** to the sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion induced by photoelectrons,as-prepared N-TiO_(2)/SCH nanocomposites exhibit much enhanced efficiency for the degradation of bisphenol A(BPA;ca.100% within 60 min under visible irradiation)in a wide pH range of 3.0-7.8,which is significantly higher than that of the pristine schwertmannite(ca.74.5%)or N-TiO_(2)(ca.10.8%).In this photo-Fenton system,the efficient degradation of BPA is mainly attributed to the oxidation by hydroxyl radical(·OH)and singlet oxygen(^(1)O_(2)).Moreover,the possible catalytic mechanisms and reaction pathway of BPA degradation are systematically investigated based on analytical and photoelectrochemical *** work not only provides a feasible means for the development of novel heterogeneous photo-Fenton catalysts,but also lays a theoretical foundation for the potential application of mineral-based materials in wastewater treatment.

关键词： Titanium dioxide Schwertmannite Fenton reaction Environmental endocrine disruptors Photocatalysis

Achieving Ultra-Broad Microwave Absorption Bandwidth Around Millimeter-Wave Atmospheric Window Through an Intentional Manipulation on Multi-Magnetic Resonance Behavior

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Nano-Micro Letters 2024年第9期16卷 291-307页

作者： Chuyang Liu Lu xu xueyu Xiang Yujing Zhang Li Zhou Bo Ouyang Fan Wu Dong‑Hyun Kim Guangbin ji School of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016JiangsuPeople’s Republic of China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuPeople’s Republic of China School of Physics Chungbuk National UniversityCheongju 28644South Korea Department of Chemistry School of ScienceTianjin UniversityTianjin 300072People’s Republic of China

The utilization of electromagnetic waves is rapidly advancing into the millimeter-wave frequency range,posing increasingly severe challenges in terms of electromagnetic pollution prevention and radar ***,existing millimeter-wave absorbers are still inadequate in addressing these issues due to their monotonous magnetic resonance *** this work,rare-earth La^(3+)and non-magnetic Zr^(4+)ions are simultaneously incorporated into M-type barium ferrite(BaM)to intentionally manipulate the multi-magnetic resonance *** leveraging the contrary impact of La^(3+)and Zr^(4+)ions on magnetocrystalline anisotropy field,the restrictive relationship between intensity and frequency of the multi-magnetic resonance is successfully *** magnetic resonance peak-differentiating and imitating results confirm that significant multi-magnetic resonance phenomenon emerges around 35 GHz due to the reinforced exchange coupling effect between Fe^(3+)and Fe^(2+)***,Mosbauer spectra analysis,first-principle calculations,and least square fitting collectively identify that additional La^(3+)doping leads to a profound rearrangement of Zr^(4+)occupation and thus makes the portion of polarization/conduction loss increase *** a consequence,the La^(3+)-Zr^(4+)co-doped BaM achieves an ultra-broad bandwidth of 12.5+GHz covering from 27.5 to 40+GHz,which holds remarkable potential for millimeter-wave absorbers around the atmospheric window of 35 GHz.

关键词： Microwave absorption Ultra-broad bandwidth M-type barium ferrite Magnetocrystalline anisotropy field Multimagnetic resonance

Heteroatom doping regulates the catalytic performance of singleatom catalyst supported on graphene for ORR

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Nano Research 2024年第3期17卷 1086-1093页

作者： ji-Kai Sun Yu-Wei Pan Meng-Qian xu Lei Sun Shaolong Zhang Wei-Qiao Deng Dong Zhai Institute of Molecular Sciences and Engineering Institute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Replacing fossil fuels with fuel cells is a feasible way to reduce global energy shortages and environmental ***,the oxygen reduction reaction(ORR)at the cathode has sluggish kinetics,which limits the development of fuel *** is significant to develop catalysts with high catalytic activity of *** single-atom catalysts(SACs)of Pt supported on heteroatom-doped graphene are potential candidates for *** we studied the SACs of Pt with different heteroatoms doping and screened out Pt-C_(4) and Pt-C_(3)O_(1) structures with only 0.13 V overpotential for ***,it is found that B atoms doping could weaken the adsorption capacity of Pt,while N or O atoms doping could enhance *** regularity was verified on Fe *** the electronic interaction analysis between Pt and adsorbate,we explained the mechanism of this regularity and further proposed a new descriptor named corrected d-band center(ε_(d-corr))to describe *** descriptor is an appropriate reflection of the number of free electrons of the SACs,which could evaluate its adsorption *** work provides a purposeful regulatory strategy for the design of ORR catalysts.

关键词： single-atom catalyst(SAC) oxygen reduction reaction(ORR) heteroatom doping corrected d-band center descriptor

Spatiotemporal evolution and influencing factors of urban resilience in the Yellow River Basin,China

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Regional Sustainability 2024年第3期5卷 54-68页

作者： ji Xiaomei NIE Zhilei WANG Kaiyong xu Mingxian FANG Yuhao Qilu University of Technology(Shandong Academy of Sciences) Jinan250100China Science and Technology Service Platform of Shandong Academy of Sciences(Pioneer Park for Overseas Students of Shandong Academy of Sciences) Jinan250100China Institute of Science and Technology for Development of Shandong Jinan250014China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

The Yellow River Basin of China is a key region that contains myriad interactions between human activities and natural *** and urbanization promote social-economic development,but they also have generated a series of environmental and ecological issues in this *** researches have evaluated urban resilience at the national,regional,urban agglomeration,city,and prefecture levels,but not at the watershed *** address this research gap and elevate the Yellow River Basin’s urban resilience level,we constructed an urban resilience evaluation index system from five dimensions:industrial resilience,social resilience,environmental resilience,technological resilience,and organizational *** entropy weight method was used to comprehensively evaluate urban resilience in the Yellow River *** exploratory spatial data analysis method was employed to study the spatiotemporal differences in urban resilience in the Yellow River Basin in 2010,2015,and ***,the grey correlation analysis method was utilized to explore the influencing factors of these *** results of this study are as follows:(1)the overall level of urban resilience in the Yellow River Basin was relatively low but showed an increasing trend during 2010–2015,and significant spatial distribution differences were observed,with a higher resilience level in the eastern region and a low-medium resilience level in the western region;(2)the differences in urban resilience were noticeable,with industrial resilience and social resilience being relatively highly developed,whereas organizational resilience and environmental resilience were relatively weak;and(3)the correlation ranking of resilience influencing factors was as follows:science and technology level>administrative power>openness>market *** research can provide a basis for improving the resilience level of cities in the Yellow River Basin and contribute to the high-quality development

关键词： Urban resilience Spatiotemporal evolution Entropy weight method Exploratory spatial data analysis method Grey correlation analysis method Yellow River Basin

Wheel-legged In-pipe Robot with a Bioinspired Hook and Dry Adhesive Attachment Device

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Journal of Bionic Engineering 2024年第3期21卷 1208-1222页

作者： Yahong Liu Yi Sun Kai Cao Shutao Wu Xiaofeng xu Qingfei Han Shikun Wen Huan Shen Guangming Chen jiajun xu Zhiwei Yu Aihong ji Lab of Locomotion Bioinspiration and Intelligent Robots College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In-pipe robots have been widely used in pipes-with smooth inner ***,current in-pipe robots face challenges in terms of moving past obstacles and climbing in marine-vessel pipeline systems,which are affected by marine biofouling and electrochemical *** paper takes inspiration from the dual-hook structure of Trypoxylus dichotomus’s feet and gecko‑like dry adhesives,proposing an in-pipe robot that is capable of climbing on rough and smooth pipe *** combination of the bioinspired hook and dry adhesives allows the robot to stably attach to rough or smooth pipe inwalls,while the wheel-leg hybrid mechanism provides better conditions for obstacle *** paper explores the attachment and obstacle-surmounting mechanisms of the ***,motion strategies for the robot are devised based on different pipe structural *** experiments showed that this robot can adapt to both smooth and rough pipe environments simultaneously,and its motion performance is superior to conventional driving *** robot’s active turning actuators also enable it to navigate through horizontally or vertically oriented 90°bends.

关键词： In-pipe robot Bioinspired attachment device Wheel-legged robot Mechanical design

Adaptive Predefined-Time Backstepping Control for Grid Connected Photovoltaic Inverter

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Energy Engineering 2024年第8期121卷 2065-2083页

作者： jiarui Zhang Dan Liu Kan Cao Ping Xiong Xiaotong ji Yanze xu Yunfei Mu Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin300072China State Grid Hubei Electric Power Research Institute Wuhan430077China State Grid Hubei Electric Power Co. Ltd.Wuhan430077China

The system performance of grid-connected photovoltaic(PV)has a serious impact on the grid *** improve the control performance and shorten the convergence time,a predefined-time controller based on backstepping technology and dynamic surface control is formulated for the inverter in the grid-connected *** time-varying tuning functions are introduced into state-tracking errors to realize the predefined-time control *** address the“computational explosion problem”in the design process of backstepping control,dynamic surface control is adopted to avoid the analytical calculations of virtual *** disturbances of the PV system are estimated and compensated by adaptive *** control parameters are chosen and the global stability of the closed-loop is ensured by Lyapunov *** results confirm the effectiveness of the proposed controller and ensure the predefined time control in the photovoltaic inverter.

关键词： Photovoltaic inverter system backstepping technology predefined-time control adaptive control

Effects of organic fertilizers on organic carbon accumulation in alkalized saline soil and silage maize yield

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 159-168页

作者： Lidong ji Lei Li Rui Wang Xing xu Fengju Zhang Guilian Mao Teng Wang School of Forestry and Prataculture Ningxia UniversityYinchuan750021China School of Agriculture Ningxia UniversityYinchuan750021China School of Ecological Environment Ningxia UniversityYinchuan 750021China School of Life Sciences Ningxia UniversityYinchuan 750021China

To understand the combined effect of organic and chemical fertilizers on soil carbon emissions and carbon balance of a farmland ecosystem,this study investigated the organic fertilizer nitrogen replacing different proportions of chemical fertilizer *** results showed that,compared to F_(100),the O_(15)F_(85) treatment increased the yield and net ecosystem productivity carbon sequestration of silage maize under mild,moderate,and severe salinization levels,as well as the contents of soil organic carbon,microbial carbon,and humin carbon,while reducing plant carbon *** O_(15)F_(85) treatment did not significantly increase soil carbon emissions(CEC),but O_(30)F_(70),O_(45)F_(55) and O_(100) treatments significantly increased *** soil carbon balance analysis showed that the farmland ecosystem was a“sink”for atmospheric CO_(2) under each *** O_(15)F_(85) treatment produced an“excitation effect”to enhance the carbon sink effect of silage maize farmland under mild,moderate and severe salinization levels while maintaining stable production and *** the O_(100) treatment increased the carbon sink of farmland under different salinization levels,the yield was significantly reduced and did not represent practical production *** analysis showed that soil organic carbon components and ecosystem carbon balance were closely related to soil total salt,pH and bulk density,while soil dissolved organic carbon,humus carbon components and carbon emissions were closely related to soil moisture and ***,the purpose of improving the carbon sink of saline-alkali land can be achieved through soil salt inhibition,soil structure remodeling and water supplement and warming regulation,which provides technical and theoretical support for reducing carbon emissions,achieving carbon neutrality and alleviating global warming.

关键词： carbon balance carbon component organic carbon organic substitution saline-alkali land