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An improved simulation of temperature field in Laser–low current MAG of thin galvanized steel sheets

International Journal of advanced Manufacturing technology 2025年第7期138卷 3441-3455页

作者： Xu, Shixiang Sun, Zhenbang Han, Yongquan Sun, Haotian Xing, Yucheng Zhang, Shiquan School of Materials Science and Engineering Inner Mongolia University of Technology Hohhot010051 China Engineering Research Center of Development and Processing Protection of Advanced Light Metals Ministry of Education Hohhot010051 China Inner Mongolia Metal Material Research Institute Baotou014034 China

This study aimed to achieve efficient and precise connection of thin steel sheets for vehicles by analyzing the thermal process of Laser-MAG hybrid high-speed welding lap of thin galvanized steel sheets. A high-speed camera combined with an NI AD data acquisition system were used, and the transition behavior and electrical signals of low-current MAG and Laser-MAG hybrid welding were examined. The thin sheet MAG welding droplet transition method mainly comprised short-circuit transfer. During the short-circuit phase, the voltage decreased and the current increased sharply, forming a short-circuit liquid column. When current increased to a certain level, the liquid bridge burst, the droplets carried heat and kinetic energy to the weld pool, the arc voltage returned to a no-load state, and the arc was re-ignited. In the arcing phase, the current first decreased steeply and then slowly, while the voltage decreased slowly and smoothly. According to the different heat source characteristics of the arc combustion and short-circuit stages during short-circuit transition, a new MAG heat source for low-current short-circuit transition was developed. This study employed a double-ellipse heat source with different powers for the arc combustion stage as well as a uniform body heat source that considered the thermal and kinetic energies of the melt droplets for the short-circuit stage. The thermal input of low current MAG welding was described by double-ellipse and uniform body heat source periodic loading. Moreover, the laser exerted an attraction and compression influence over the arc during the hybrid welding, which promoted the droplet transfer. Therefore, based on the novel MAG heat source, a hybrid Laser-MAG heat source in the short-circuit transition mode was developed. The laser beam heat source was described using a three-dimensional column heat source, the arc attraction and compression by the laser were considered indirectly through distribution parameter tuning for th

关键词： High speed cameras

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Temperature Dependent Thermal and Elastic Properties of High Entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2):Molecular Dynamics Simulation by Deep Learning Potential

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Journal of materials Science & technology 2021年第13期72卷 8-15页

作者： Fu-Zhi Dai Yinjie Sun Bo Wen Huimin Xiang Yanchun Zhou Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing100076China

High entropy diborides are new categories of ultra-high temperature ceramics,which are believed promising candidates for applications in hypersonic ***,knowledge on high temperature thermal and mechanical properties of high entropy diborides is still lacking unit *** this work,variations of thermal and elastic properties of high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) with respect to temperature were predicted by molecular dynamics ***,a deep learning potential for Ti-Zr-Hf-Nb-Ta-B diboride system was fitted with its prediction error in energy and force respectively being 9.2 meV/atom and 208 meV/A,in comparison with first-principles ***,temperature dependent lattice constants,anisotropic thermal expansions,anisotropic phonon thermal conductivities,and elastic properties of high entropy(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) from 0℃to 2400℃were evaluated,where the predicted room temperature values agree well with experimental *** addition,intrinsic lattice distortions of(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) were analyzed by displacements of atoms from their ideal positions,which are in an order of 10^(-3) A and one order of magnitude smaller than those in(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))*** indicates that lattice distortions in(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2) is not so severe as *** the new paradigm of machine learning potential,deep insight into high entropy materials can be achieved in the future,since the chemical and structural complexly in high entropy materials can be well handled by machine learning potential.

关键词： High entropy diborides Machine learning potential Thermal properties Elastic properties Molecular dynamics

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Cobalt doping boosted electrocatalytic activity of CaMn3O6 for hydrogen evolution reaction

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Nano Research 2022年第4期15卷 2870-2876页

作者： Qun Li Kaisi Liu Siwei Gui Jiabin Wu Xiaogang Li Zaifang Li Hongrun Jin Hui Yang Zhimi Hu Wenxi Liang Liang Huang Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China China-Australia Institute for Advanced Materials and Manufacturing Jiaxing UniversityJiaxing 314001China State Key Laboratory of Material Processing and Die&Mold Technology Department of MechanicsSchool of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The development of earth-abundant-metal-based electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction(HER)is crucial for the clean and renewable energy ***,we report a molten-salt method to synthesize Co-doped CaMn_(3)O_(6)(CMO)nanowires(NWs)as effective electrocatalyst for *** as-obtained CaMn_(3-x)Co_(x)O_(6)(CMCO)exhibits a small onset overpotential of 70 mV,a required overpotential of 140 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 39 mV·dec^(-1)in 0.1 M HClO_(4),and a satisfying long-term *** characterizations combined with density functional theory(DFT)calculations demonstrate that the obtained HER performance can be attributed to the Co-doping which altered CMO’s surface electronic structures and *** the simplicity of synthesis route and the abundance of the pertinent elements,the synthesized CMCO shows a promising prospect as a candidate for the development of earth-abundant,metal-based,and cost-effective electrocatalyst with superior HER *** results also establish a strategy of rational design and construction of novel electrocatalyst toward HER by tailoring band structures of transition metal oxides(TMOs).

关键词： CMCO nanowires hydrogen evolution reaction electronic structure dopant

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A Novel Method for Frequency Selective Surface Design Using Deep Learning with Improved Particle Swarm Algorithm 9

A Novel Method for Frequency Selective Surface Design Using ...

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9th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, MAPE 2022

作者： Cong, Riqiu Liu, Ning Gao, Xiang Zhang, Chunbo Yang, Kaihua Sheng, Xianjun Dalian University of Technology Dalian China Lianyungang Jari Electronics Co. Ltd Lianyungang China Aerospace Institute of Advanced Material & Processing Technology Beijing China

ISBN: (数字)9781665427753

ISBN: (纸本)9781665427753

This paper presents a design method for frequency selective surface (FSS) based on the deep neural network and improved particle swarm algorithm (IPSO). In the proposed method, the forward prediction network (FPN) based on the fully connected network is established to fast predict the transmission coefficient of FSS. Combined with the FPN, the IPSO is used to optimize the structural parameters of FSS. Compared with the traditional iterative optimization method based on full-wave simulation, this method greatly improves the optimization efficiency of FSS. For example, a band-stop FSS is optimized with the proposed method in 210.6s, and the optimization efficiency increases by more than 99%. Simulation results show that the transmission coefficient errors of key frequency points between optimization results and objectives are less than 1 dB. And the deviation of the center frequency and the bandwidth of the target frequency bands is less than 0.81% and 4.1%, respectively. © 2022 IEEE.

关键词： Deep neural networks

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Crystallographic micro-mechanism of faceted crack initiation in near-αtitanium alloy Ti6321 under room-temperature fatigue and dwell fatigue loadings

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材料科学技术（英文版） 2025年第2期205卷 109-126页

作者： Wenyuan Zhang Qiaonan Shu Jiangkun Fan Panpan Fan Xiangyi Xue Peng Jiang Minjie Lai Bing Tang Zhiqian Liao Hongchao Kou Jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China National & Local Joint Engineering Research Center for Precision Thermoforming Technology of Advanced Metal Materials Xi'an 710072China Chongqing Innovation Center Northwestern Polytechnical UniversityChongqing 401135China Luoyang Ship Material Research Institute Luoyang 471000China

Crack initiation mechanism of dwell fatigue has always been a key problem in rationalizing the dwell effect,and it is not completely understood *** study conducted stress-controlled low-cycle fatigue and dwell fatigue tests on Ti-6Al-3Nb-2Zr-1Mo alloy with bimodal microstructure to reveal its microstruc-tural characteristics and crack initiation *** study demonstrated that the faceted primaryα nodules located near the specimen surface acted as crack initiation sites during both fatigue and dwell fatigue *** trace analysis revealed that faceted cracking occurred at(0001)basal plane with the maximum Schmid factor value through a special cracking mode referred to as(0001)twist boundary *** criteria of parameters C1 and C2 were proposed based on experimental observation and molecular dynamics simulations,which well identify candidates for(0001)twist boundary crack *** demonstrated that grain pairs combining a moderately high Schmid factor for basal slip and a well-orientated Burgers vector in the out-of-surface plane was the preferable location for surface(0001)twist-boundary crack initiation,and grain pairs combining a high Schmid factor for basal slip and a high normal stress on basal plane are perfect candidates for subsurface *** on this,phenomeno-logical models are proposed to explain the surface(0001)twist-boundary cracking mechanism from the perspective of surface extrusion-intrusion-induced micro-notches.

关键词： Titanium alloy Dwell fatigue Facet Fatigue crack initiation Crystallographic orientation

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Synthesized robust and thermal stable zirconia aerogel by using N, N-dimethylformamide as a drying inhibitor 4

Synthesized robust and thermal stable zirconia aerogel by us...

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2023 4th International Conference on material Chemistry and Composite materials, MCCM 2023

作者： Hou, Sifan Sun, Yinjie Zhang, Kai Li, Guoqi Fan, Jinpeng Institute of Advanced Structural Technology Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology Beijing10081 China Aerospace Research Institute of Materials and Processing Technology Beijing100076 China

N, N-dimethylformamide (DMF) is used as a drying inhibitor to prepare ZrO2 aerogels. The properties were investigated and the result reflected that adding DMF can get bulk aerogels with better mechanical strength (0.51 MPa), lower density (0.38 g/cm3), lower thermal conductivity (0.024 W·m-1·K-1), and higher specific surface area (123.46 m2/g) after heat treatment. Its performance as a drying inhibitor is better than that of formamide (FA). It indicates that DMF can be used as a drying inhibitor to prepare zirconia aerogel with excellent thermal stability and mechanical strength. © Published under licence by IOP Publishing Ltd.

关键词： Aerogels

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Simple preparation of silicone rubber Pickering emulsions using silica nanoparticles for water-borne thermal protection coating

Simple preparation of silicone rubber Pickering emulsions us...

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作者： Gao, Chao He, Chen Zeng, Yibing Wu, Xiaohui Yan, Xue Wu, Xiaofeng Li, Chenguang Li, Boqian Feng, Anchao Aerospace Research Institute of Materials and Processing Technology Beijing100076 China Center of Advanced Elastomer Materials College of Materials Science and Engineering Beijing University of Chemical Technology Beijing100029 China

In this study, we aimed to develop stable silicone rubber Pickering emulsions by employing silica nanoparticles as stabilizers in order to produce a water-borne thermal protection coating. Initially, silica nanoparticles were synthesized using the Stöber method and subsequently functionalized with γ-glycidoxypropyltrimethoxysilane (GTMS). The size and grafting efficiency of the GTMS-modified silica nanoparticles were characterized using transmission electron microscopy and thermogravimetric analysis, respectively. Furthermore, the functionalization mechanism was elucidated by monitoring the pH and Zeta potential of the silica sols. Subsequently, the silicone rubber Pickering emulsion was prepared via the emulsion inversion point method and characterized using transmission electron microscopy. The emulsification process was analyzed by measuring the conductivity of the emulsion during the phase transition. Finally, the water-borne coating was formulated by blending the emulsions with Kaolin, glass fiber, and glass microspheres. The thermal protection performance of the resulting coating was evaluated under typical test conditions, with the highest heat flow reaching 242 kW m−2 for 40 s. © 2023 IUPAC & De Gruyter.

关键词： Emulsification

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Synthesis and mechanical and elevated temperature tribological properties of a novel high-entropy(TiVNbMoW)C_(4.375) with carbon stoichiometry deviation

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Journal of advanced Ceramics 2023年第2期12卷 242-257页

作者： Jicheng LI Yanchun ZHOU Yunfeng SU Shuna CHEN Qiuan SUN Hengzhong FAN Junjie SONG Litian HU Yongsheng ZHANG State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China

High-entropy carbides are a nascent group of ceramics that are promising for high-temperature applications due to the combination of good stability,high hardness(H),high strength,and superior creep resistance that they *** to high melting points and low lattice diffusion coefficients,however,the high-entropy carbides are usually difficult to consolidate to a nearly full *** cope with this challenge,herein,binary carbides including TiC,V_(8)C_(7),NbC,Mo_(2)C,and WC with different carbon stoichiometry were used to prepare dense high-entropy(TiVNbMoW)C_(4.375),and the influence of carbon vacancy on formation ability and mechanical properties of carbon-deficient high-entropy(TiVNbMoW)C_(4.375) were ***,although the starting binary carbides have different crystal structures and carbon stoichiometry,the as-prepared high-entropy material showed a rock-salt structure with a relatively high density(98.1%)and good mechanical properties with hardness of 19.4±0.4 GPa and fracture toughness(KIC)of 4.02 MPa·m^(1/2).More importantly,the high-entropy(TiVNbMoW)C_(4.375) exhibited low coefficient of friction(COF)at room temperature(RT)and 800℃.Wear rate(W)gradually increased with the temperature rising,which were attributed to the formation of low-hardness oxidation films at high temperatures to aggravate *** 800℃,lubricating films formed from sufficient oxidation products of V_(2)O_(5) and MoO_(3) effectively improved tribological behavior of the high-entropy(TiVNbMoW)C_(4.375).Wear mechanisms were mainly abrasive wear resulting from grain pullout and brittle fracture as well as oxidation wear generated from high-temperature *** results are useful as valuable guidance and reference to the synthesis of high-entropy ceramics(HECs)for sliding parts under high-temperature serving conditions.

关键词： high-entropy ceramics(HECs) transition metal(TM)carbides carbon stoichiometry deviation tribological performances wear

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Janus MXene film with gradient structure for highly efficient terahertz and infrared electromagnetic absorption

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Nano Research 2025年第1期18卷 434-442页

作者： Shaodian Yang Weiqiang Huang Zhiqiang Lin Zibo Chen Rongliang Yang Yi Jia Xuebin Liu Rui Wang Zhiping Zeng Yougen Hu Huanjun Chen Xuchun Gui11 State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275China National Key Laboratory of Materials for Integrated Circuits Shenzhen Institute of Advanced Electronic MaterialsShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China China Academy of Aerospace Science and Innovation Beijing 100176China Guangdong Province Key Laboratory of Display Material and Technology Guangzhou 510275China School of Materials Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China

Electromagnetic interference (EMI) shielding inhigh-frequency range, especially the rapidly growing terahertz(THz) frequency range, attracts increasing attention due tothe potential application of terahertz in 6G wirelesscommunication, and security inspection. However, traditionalconductive EMI films typically achieve high shieldingeffectiveness through strong reflection, which may causesecondary pollution to other devices. Here, a gradientstructure strategy was proposed to constructTi_(3)C_(2)Tx/hydroxypropyl methyl cellulose (HPMC) film, in whichthe content of Ti_(3)C_(2)Tx gradually increases along the thicknessdirection, resulting in different conductivity of the two surfaces(surface-M and surface-H) for the film. The obtained gradientfilmexhibits an EMI shielding efficiency of over 48.5 dB in theTHz range (0.2-1.6 THz) at a thickness of 40 μm. Especially,as the THz waves incident from the surface-H to the film, the absorption effectiveness reaches 48.2 dB (average absorbedpower loss up to 91.4%), and the reflection effectiveness is only 0.3 dB. In additions, the gradient-film also demonstrates ahigh absorption rate of 95.5% in the infrared band (2.5-16.7 μm). Moreover, the gradient-film exhibits an excellent tensilestress and Young’s modulus value of 173.1 MPa and 2.8 GPa, respectively. Therefore, the gradient-film proposed in thiswork, with excellent electromagnetic absorption in both THz and infrared band, provides a promising candidate for the nextgenerationEMI shielding applications.

关键词： electromagnetic interference shielding Janus film terahertz MXene

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Garnet-type solid-state electrolytes:crystal structure,interfacial challenges and controlling strategies

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Rare Metals 2023年第10期42卷 3177-3200页

作者： Ting-Ting Wu Sijie Guo Bing Li Chang-Yu Shen Xian-Hu Liu An-Min Cao National Engineering Research Center for Advanced Polymer Processing Technology Key Laboratory of Advanced Material Processing&Mold(Ministry of Education)Zhengzhou UniversityZhengzhou450002China CAS Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of Sciences(CAS)Beijing100190China University of Chinese Academy of Sciences Beijing100049China

All-solid-state batteries(ASSBs) hold great promise for next-generation energy storage technologies owing to their advantage in different aspects such as energy density,safety,and wide temperature ***,the use of solid-state electrolytes(SSEs) instead of liquid ones meanwhile brings serious concerns related to the point-to-point contact between SSEs and electrodes,which is known to result in high interface resistance and inhomogeneous distribution of charges during the Li^(+)plating/stripping process,eventually leading to a premature failure of *** review focuses on the garnet-type SSEs in the formula of Li_(7)La_(3)Zr_(2)O_(12)(LLZO),and discusses the structure-performance relationship of this ceramic electrolyte in detail to achieve a clear understanding of its Li^(+)transmission ***,the challenges of cubic phase LLZO(c-LLZO) for their application in solidstate batteries(SSBs) are demonstrated by the Li/LLZO interface,which features the importance of Li metal wettability and dendrite suppression for sustainable ***,this review summarizes the recent research strategies to combat these contact issues at the Li/LLZO interface,highlighting the essential role played by surface modification of LLZO *** the obtained insights,perspectives for future research on LLZO to accelerate its potential development of SSBs in commercialized applications are also provided.

关键词： Solid-state electrolytes(SSEs) Garnet-type electrolytes Li^(+)ion conductivity Interface engineering Lithium dendrites

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