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A method based on circumferential strain distribution for roller path design in conventional spinning of thin-walled conical part with curved surface

Research Square

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Research Square 2021年

作者： Wang, Yongdi Li, Hongwei Gao, Pengfei Zhan, Mei Yan, Xinggang Niu, Haotong State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment School of Materials Science and Engineering Northwestern Polytechnical University P.O. Box 542Shaanxi Xi'an710072 China

Multi-pass conventional spinning is the preferable forming technology for the forming of thin-walled conical part with curved surface (TCPCS) in aerospace field. In multi-pass conventional spinning, the design of roller path is a critical problem due to its sensitive effect on the deformation mode and forming defect during spinning process. However, at present, the roller path is still mainly designed based on experience and trial-and-error, which seriously restricts the high-performance spinning of TCPCS. In this work, a new quantitative method based on circumferential strain distribution was developed for the roller path design in multi-pass conventional spinning of TCPCS. In this method, the total required circumferential strain for the forming of final TCPCS by conventional spinning was firstly determined. Then, the spinning passes number were obtained through dividing the total required circumferential strain by the ultimate circumferential strain producing the spinning instability (Εθult). As for the roller path profile in each pass, it is divided into two sections and determined respectively, i.e. the attaching mandrel section and the performing section. The attaching mandrel section presents the same profile of mandrel. The profile of preforming section is determined point-by-point by distributing the rest of circumferential strain {Εθni} to produce the final TCPCS. The point-by-point distributed circumferential strain is half of the {Εθni} at the initial stage until reaches the half of Εθult, then it will keep the half of Εθult to the end. The proposed new method of roller path design was validated by finite element simulation, where well spinning stability, wall thickness distribution and roundness were obtained. This method provides a quantitative, high-efficient and universal way for the roller path design in conventional spinning of TCPCS. © 2021, CC BY.

关键词： Thin walled structures

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Al-Doped LiNi0.5Mn1.5O4 Cathode Material for High-Rate and High-Voltage Lithium-Ion Batteries

SSRN

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SSRN 2023年

作者： Li, Meixuan Cheng, Jianfeng Weng, Yaqing Liu, Yimeng Zhang, Long Chen, Jian-An Wang, Chunxia Wen, Jiawei Huang, Guoyong Xu, Shengming College of New Energy and Materials China University of Petroleum Beijing102249 China State Key Laboratory of Heavy Oil Processing College of Chemical Engineering China University of Petroleum Beijing102249 China Institute of Applied Chemistry Jiangxi Academy of Sciences Nanchang330029 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing100084 China Beijing Key Lab of Fine Ceramics Tsinghua University Beijing100084 China

The low cost, high operating voltage, and high energy density of LiNi0.5Mn1.5O4 (LNMO) make it a promising candidate for power battery applications. Nevertheless, its poor conductivity and performance at high temperatures limit its further application. In this paper, Al-doped LNMO sample was prepared by a hydrothermal strategy, and the influence of Al doping on the electrochemical characteristics of LNMO was examined employing density functional theory calculations. The density of states computations indicates that the strength of all the spectral bands of Al@LNMO is smaller than those of LNMO pristine material, implying that the incorporation of Al3+ has effectively reduced the overall valence state of LNMO. Energy band calculations demonstrate that the band gap of Al@LNMO (0.0018 eV) is considerably less than that of LNMO (0.5601 eV), indicating that Al doping can significantly improve the conductivity of LNMO. Structural Characterization by XRD and FT-IR illustrates that the crystal structure of the synthesized Al@LNMO is Fd-3m. SEM results show that the morphology of the synthesized Al@LNMO sample is octahedral. In addition, electrochemical cycling tests exhibit that the capacity retention of Al@LNMO after 100 cycles is 82.9% and 79.1% tested at 25 °C and 50 °C, respectively. The capacity retention at 50 °C is similar to that at 25 ℃, which suggests that Al@LNMO has appreciable high-temperature stability. Moreover, the Warburg impedance of Al@LNMO is found small demonstrated by CV test, indicating that Al doping can improve the conductivity of LNMO, which is consistent with density functional theory calculations. © 2023, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Determining the electrochemical activation mechanism of Prussian blue analog precatalysts for a high-efficiency oxygen evolution reaction

Energy Materials and Devices

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Energy materials and Devices 2023年第2期1卷 119-130页

作者： Wei Hua Huanhuan Sun Yueying Li Yu Zhang Jian-Gan Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and Engi-neeringNorthwestern Polytechnical University and Shaanxi Joint Lab of Graphene(NPU)Xi’an 710072China New Energy(Photovoltaic)Industry Research Center Qinghai UniversityXining 810016China School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China

Prussian blue analogs(PBAs)are effective precatalysts for the oxygen evolution reaction(OER);however,the underlying mechanism of their electrochemical activation is still not well *** this study,we designed and constructed PBA-based precatalysts to determine the electrochemical activation mechanism and achieve high-efficiency *** PBAs undergo in situ electrochemical transformation to form the corre-sponding metal(oxy)hydroxides(M(O)OH)as the true OER *** importantly,the hexacyanoferrate ligands undergo repetitive interfacial coordination/etching with/from M(O)OH during the activation *** distinct mechanism could achieve in situ Fe doping and enable defect *** defect-enriched Fe-NiOOH derived from a well-designed NiHCF/Ni(OH)2 precatalyst requires a low overpotential of 227 mV to reach a current density of 10 mA cm−2 and works stably at 130 mA cm−2 over 100 *** study provides fundamental insights into the electrochemical activation mechanism for developing advanced precatalysts for OER.

关键词： electrochemical activation Prussian blue analogs oxygen evolution reaction water splitting

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The development of 3D printing technology and the current situation of controlling defects in SLM technology

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China Welding 2020年第3期29卷 9-19页

作者： Yin Yan Zhang Yuan Dong Kaiji Zhang Ruihua Chai Xutian State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China China Iron&Steel Research Institute Group Beijing 100081China Hardware Knife Cut Industrial Technology Research Institute Yangjiang Yangjiang 529533China

With unique manufacturing technology,the additive manufacturing technology divides the three-dimensional object into countless two-dimensional *** with the traditional material reduction manufacturing method,it has the characteristics of saving materials,being fast,and especially suitable for single and small batch parts and the rapid manufacturing of parts with complex shapes and internal *** this paper,various methods of additive manufacturing technology are *** paper introduces the characteristics of selective laser melting technology and its forming equipment *** this basis,the technical defects of selective laser melting technology are analyzed,and the status of controlling defects in SLM technology is *** the end,the prospects of additive manufacturing technology are described.

关键词： additive manufacturing technology selective laser melting density support structure

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Sulfur-deficient MoS2 encapsulated in hollow mesoporous carbon spheres as a functional polysulfide mediator

Sulfur-deficient MoS2 encapsulated in hollow mesoporous carb...

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中国化学会第二十次全国电化学大会

作者： Hong-En Wang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

Lithium-sulfur batteries have the advantages of high theoretical energy density(2600 Wh kg-1), low-cost and environmental friendliness, which is one of the most promising secondary battery systems. However, the practical application of Li-S batteries has still been restricted by the low Coulombic efficiency and rapid capacity decay deriving from the low conductivity of sulfur cathode, large volume expansion（～80%） during discharging, and serious lithium corrosion/dendrite of anode, particularly, high dissolution of the discharge intermediate polysulfides（LiPSs） in electrolyte and shuttle effect between cathode and anode.

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Investigation of Deformation and Fracture Mechanisms in Two-dimensional Gallium Telluride Multilayers Using Nanoindentation

arXiv

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arXiv 2022年

作者： Zhou, Yan Zhou, Shi Ying, Penghua Zhao, Qinghua Xie, Yong Gong, Mingming Jiang, Pisu Cai, Hui Chen, Bin Tongay, Sefaattin Jie, Wanqi Zhang, Jin Wang, Tao Liu, Dong Kuball, Martin H. H. Wills Physics Laboratory University of Bristol Tyndall Avenue BristolBS8 1TL United Kingdom University of Science and Technology of China Hefei230026 China School of Science Harbin Institute of Technology Shenzhen518055 China State Key Laboratory of Solidification Processing School of Materials Science Northwestern Polytechnical University Xi'An710072 China School of Advanced Materials and Nanotechnology Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices Xidian University Xi'An710071 China School for Engineering of Matter Transport and Energy Arizona State University TempeAZAZ85287 United States

Two-dimensional (2D) materials possess great potential for flexible devices, ascribing to their outstanding electrical, optical, and mechanical properties. However, their mechanical deformation property and fracture mechanism, which are inescapable in many applications like flexible optoelectronics, are still unclear or not thoroughly investigated due methodology limitations. In light of this, such mechanical properties and mechanisms are explored on example of gallium telluride (GaTe), a promising optoelectronic candidate with an ultrahigh photo-responsibility and a high plasticity within 2D family. Considering the driving force insufficient in atomic force microscopy (AFM)-based nanoindentation method, here the mechanical properties of both substrate-supported and suspended GaTe multilayers were systematically investigated through full-scale Berkovich-tip nanoindentation, micro-Raman spectroscopy, AFM, and scanning electron microscopy. An unusual concurrence of multiple pop-in and load-drop events in loading curve was observed. By further correlating to molecular dynamics calculations, this concurrence was unveiled originating from the interlayer sliding mediated layers-by-layers fracture mechanism within GaTe multilayers. The van der Waals force between GaTe multilayers and substrates was revealed much stronger than that between GaTe interlayers, resulting in the easy sliding and fracture of multilayers within GaTe. This work provides new insights into the deformation and fracture mechanisms of GaTe and other similar 2D multilayers in flexible applications. Copyright © 2022, The Authors. All rights reserved.

关键词： Substrates

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Charge redistribution, charge order and plasmon in La2−xSrxCuO4/La2CuO4 superlattices

arXiv

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arXiv 2023年

作者： Li, Qizhi Ju, Lele Huang, Hsiaoyu Zhang, Yuxuan Zou, Changwei Ren, Tianshuang Singh, A. Zhang, Shilong Qiu, Qingzheng Xiao, Qian Huang, Di-Jing Xie, Yanwu Chen, Zhen Peng, Yingying International Center for Quantum Materials School of Physics Peking University Beijing100871 China Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation Zhejiang Province Key Laboratory of Quantum Technology and Device Department of Physics Zhejiang University Hangzhou310027 China National Synchrotron Radiation Research Center Hsinchu30076 Taiwan State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing100084 China Department of Physics and Astrophysics University of Delhi New Delhi110007 India Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Collaborative Innovation Center of Quantum Matter Beijing100871 China

Interfacial superconductors have the potential to revolutionize electronics, quantum computing, and fundamental physics due to their enhanced superconducting properties and ability to create new types of superconductors. The emergence of superconductivity at the interface of La2−xSrxCuO4/La2CuO4 (LSCO/LCO), with a Tc enhancement of ∼ 10 K compared to the La2−xSrxCuO4 bulk single crystals, provides an exciting opportunity to study quantum phenomena in reduced dimensions. To investigate the carrier distribution and excitations in interfacial superconductors, we combine O K-edge resonant inelastic X-ray scattering and atomic-resolved scanning transmission electron microscopy measurements to study La2−xSrxCuO4/La2CuO4 superlattices (x=0.15, 0.45) and bulk La1.55Sr0.45CuO4 films. We find direct evidence of charge redistribution, charge order and plasmon in LSCO/LCO superlattices. Notably, the observed behaviors of charge order and plasmon deviate from the anticipated properties of individual constituents or the average doping level of the superlattice. Instead, they conform harmoniously to the effective doping, a critical parameter governed by the Tc of interfacial superconductors. Copyright © 2023, The Authors. All rights reserved.

关键词： Copper compounds

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Editorefficient Degradation of Sulfamethoxazole in Various Waters with Peroxymonosulfate Activated by Magnetic Sludge Biochar: Surface-Bound Radical Mechanism

SSRN

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SSRN 2022年

作者： Chen, Xi Qian, Shufang Ma, Yongfei Zhu, Jinyao Shen, Shitai Tang, Jiayi Ding, Yongzhen Zhi, Suli Zhang, Keqiang Yang, Lie Zhang, Zulin Hubei Key Laboratory of Mineral Resources Processing and Environment School of Resources and Environmental Engineering State Key Laboratory of Silicate Materials for Architectures Wuhan University of Technology Wuhan430070 China Agro-Environmental Protection Institute Ministry of Agriculture and Rural Affairs Tianjin300191 China The James Hutton Institute Craigiebuckler AberdeenAB15 8QH United Kingdom

First time, this study synthesized a magnetic sludge biochar (MSBC) as an activator of peroxymonosulfate (PMS) to eliminate sulfamethoxazole (SMX). The removal efficiency of SMX reached 96.1% at t=60 min by PMS/MSBC system. The larger surface area and magnetic Fe3O4 of MSBC surface enhanced its activation performance for PMS. The PMS decomposition, premixing and reactive oxygen species (ROS) identification experiments combined with Raman spectra analysis demonstrated that the degradation process was dominated by surface-bound radicals. The transformed products (TPs) of SMX and the main degradation pathways were identified and proposed. The ecotoxicity of all TPs was lower than that of SMX. The magnetic performance was beneficial for its reuse and the removal efficiency of SMX was 83.3% even after five reuse cycles. Solution pH, HCO3- and CO32- were the critical environmental factors affecting the degradation process. MSBC exhibited environmental safety for its low heavy metal leaching. PMS/MSBC system also performed excellent removal performance for SMX in real waters including drinking water (88.1%), lake water (84.3%), Yangtze River water (83.0%) and sewage effluent (70.2%). This study developed an efficient PMS activator for SMX degradation in various waters and provided a workable way to reuse and recycle municipal sludge. © 2022, The Authors. All rights reserved.

关键词： Potable water

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Self-assembled Nanostructures and Derived Nanocarbon materials for Electrochemical Energy Storage

Self-assembled Nanostructures and Derived Nanocarbon Materia...

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中国化学会第二十次全国电化学大会

作者： Qi Li Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

Self-assembly of functional units represents an important synthetic approach in the rational design of nanomaterials with precisely-controlled chemical compositions, nanostructures and desired properties, and hence finds vast applications in areas including but not limited to biomedical engineering, separation, energy storage and conversion. The functional units which can be used in self-assembly range from small molecules, metal ions, clusters, nanoparticles to large polymeric molecules. Finely tuning the functional groups of assembly units and the bonding/interactions between the units can generate versatile materials with unique structures and properties, thus leading to the desired performances for various applications. Notably, under varied external conditions, the chemical bonding, interactions between the assembly units and the structures can also be varied, which further endows these materials with responsive properties for applications in multidisciplinary areas. In recent years, I have studied a series of self-assembled nanostructured materials which are based on metal-organic coordinative compounds constructed between metal ions and organic ligands. Nanostructuring of these materials endow them with greatly enhanced properties in electrochemical energy storage. Moreover, in combination with controlled pyrolysis and understanding of the structure-property relationship, the rational design and controlled synthesis of nanocarbon composite electrode materials towards high-performance electrochemical energy storage and conversion becomes feasible. In this talk, I will present some of our recent work on the rational design of self-assembled metal-organic nanostructures and their derived nanocarbon materials for electrochemical energy storage.

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New Penta- and Hexa-Coordinated Titanium Sites in Titanium Silicalite-1 Catalyst for Propylene Epoxidation

SSRN

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SSRN 2022年

作者： Wang, Yanli Kong, Xiangguang Yang, Hong Zuo, Yi Tian, Dongxu Hou, Guangjin Su, Yaqiong Feng, Zhaochi Guo, Xinwen Li, Can State Key Laboratory of Fine Chemicals Frontier Science Center for Smart Materials PSU-DUT Joint Center for Energy Research School of Chemical Engineering Dalian University of Technology No.2 Linggong Road Dalian116024 China School of Engineering The University of Western Australia 35 Stirling Highway PerthWA6009 Australia State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian116023 China School of Chemistry Xi'an Key Laboratory of Sustainable Energy Materials Chemistry State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'An710049 China State Key Laboratory of Heavy Oil Processing China

Creating and identifying catalytically active titanium sites is vital to further enhance performance of titanium-containing zeolites, particularly for environmentally friendly titanium silicalite-1 catalyst (TS-1). Herein, we prepared a typical TS-1 with two new Ti-sites including the penta-coordinated Ti(OH)2(OSi)3 and hexa-coordinated Ti(OH)4(OSi)2. They are identified by UV resonance Raman spectroscopy and their coordination structures delineated by density functional theory calculations. Evaluated by propylene epoxidation to propylene oxide, Ti(OH)4(OSi)2 is more active than Ti(OH)2(OSi)3. Furthermore, Ti(OH)4(OSi)2 delivers the catalytic activity about 8.7 times the activity of known tetra-coordinated framework Ti(OSi)4 sites. Thus, Ti(OH)4(OSi)2 is found to be highly active in this reaction. © 2022, The Authors. All rights reserved.

关键词： Zeolites

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