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Refill friction stir spot welding (RFSSW): a review of processing, similar/dissimilar materials joining, mechanical properties and fracture mechanism

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Journal of Iron and Steel Research International 2024年第8期31卷 1825-1839页

作者： Yun-qiang Zhao Hao-kun Yang Aloshyn Andriia Hong-hang Lo Jia-xin Li Guangdong provincial key laboratory of advanced welding technology China-Ukraine Institute of WeldingGuangdong Academy of SciencesGuangzhou 510000GuangdongChina Smart Manufacturing Division Hong Kong Productivity CouncilHong Kong 999077China E.O.Paton Electric welding Institute of National Academy of Sciences of Ukraine Kiev 01001KievanUkraine

Refill friction stir spot welding(RFSSW)provides a novel method to join similar and/or dissimilar metallic materials without a key-hole in the center of the *** the key-hole free characterization,the similar/dissimilar RFSSW joint exhibits remarkable and endurable characteristics,including high shear strength,long fatigue life,and strong corrosion *** the meanwhile,as the key-hole free joint has different microstructures compared with conventional friction stir spot welding,thus the RFSSW joint shall possess different shear and fatigue fracture mechanisms,which needs further *** explore the underlying failure mechanism,the similar/dissimilar metallic material joining parameters and pre-treatment,mechanical properties,as well as fracture mechanisms under this novel technology will be *** details,the welding tool design,welding parameters setting,and the influence of processing on the lap shear and fatigue properties,as well as the corrosion resistance will be mainly ***,the roadmap of RFFSW is also discussed.

关键词： Refill friction stir spot welding Processing Mechanism Similar materials joining Dissimilar materials joining Microstructure Mechanical property Fracture mechanism

Chemoselective epoxidation of electron-deficient olefins with molecular oxygen via conjugated olefins epoxidation and BHT hydroxylation

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Science China Chemistry 2024年第9期67卷 3012-3018页

作者： Jia Nie Huanfeng Jiang Chuanle Zhu School of Chemistry and Chemical Engineering Key Lab of Functional Molecular Engineering of Guangdong ProvinceSouth China University of TechnologyGuangzhou 510640China Guangdong provincial key laboratory of Technique and Equipment for Macromolecular advanced Manufacturing South China University of TechnologyGuangzhou 510640China

The chemoselective epoxidation of electron-deficient olefins in the presence of electron-rich alkene moieties is *** chemoselective epoxidation strategy undergoes a conjugated olefin epoxidation and BHT hydroxylation process to give various useful oxiranes in high yields,especially for the 2-substituted ***,this protocol features mild conditions,is transition-metal free,operationally simple,and gram-scalable,and tolerates diverse functional *** candidate HSD-16 is synthesized smoothly by this *** studies indicate molecular oxygen is the terminal oxidant and the O-source of the oxiranes.

关键词： chemoselective epoxidation alkene fluorine molecular oxygen

Study on Catalytic Behavior of Iron-based Catalyst with IITP as Electron Donor in the Polymerization of Butadiene

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Chinese Journal of Polymer Science 2024年第5期42卷 612-619,I0007页

作者： Shi-Liang Xu Ying-Nan Zhao Yao Yu Qi Yang Li-Hua Na Heng Liu Chun-Yu Zhang Xue-Quan Zhang key laboratory of advanced Rubber Material Ministry of EducationSchool of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China Shandong provincial College laboratory of Rubber Material and Engineering School of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China key lab of Rubber-Plastics Ministry of Education/Shandong Provincial Key Lab of Rubber-plasticsSchool of Polymer Science and EngineeringQingdao University of Science&TechnologyQingdao266042China

In this study,a novel iron-based catalyst system,Fe(acac)3/(isocyanoimino)triptenylphosphorane(IITP)/AlR3,was employed for the synthesis of syndiotactic 1,2-polybutadiene in *** catalyst system exhibits remarkably high catalytic activity,achieving a polymerization activity of 762 kgpolymer·molcatalyst^(-1)·h^(-1)at 50℃with a[BD]/[Fe]molar ratio of ***,living polymerization characteristic were observed during the investigation of the polymerization kinetics of 1,3-butadiene *** characteristics were well demonstrated by a narrow molecular weight distribution(PDI≈2.0)of the resulting polybutadiene and a linear relationship between-ln(1-c)and polymerization time as well as number average molecular weight and polymer *** resultant polymer showed a 1,2-selectivity of approximately 76%and stereoregularity ranging from 62%to 73%(rrrr).Additionally,through kinetic studies on polymerization reaction,an apparent activation energy Ea value of this catalytic system was calculated to be 84.98 kJ·mol^(-1),which suggests that high polymerization temperature favors efficient polymerization.

关键词： Iron catalyst Syndiotactic 1,2-polybutadiene Elastomers Donor Selectivity

Hot deformation behavior and microstructure evolution of GH3536-TiB_(2) composites fabricated by powder metallurgy

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Science China(Technological Sciences) 2024年第7期67卷 2107-2124页

作者： ZHOU ShiPeng WANG Shuai HUANG LuJun ZHANG Rui CHEN Xin MENG FanChao CHEN Run SUN FengBo WANG CunYu GENG Lin School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State key laboratory of advanced welding and Joining Harbin Institute of TechnologyHarbin 150001China

The hot deformation behavior and microstructure evolution of GH3536-TiB2composites fabricated by powder metallurgy(PM)were examined in the temperature range of 950–1150℃ and strain rate range of 0.001–1 s^(-1). The hot compression stress-strain curves and the constitutive equation were obtained. In addition, the hot processing map was drawn, which indicated that the appropriate hot working window was 950–1050℃/0.001–0.1 s^(-1)and 1050–1100℃/0.001–0.01 s^(-1). The microstructure analysis showed that the splitting and spheroidization of M3B2led to a decrease in size and volume fraction at 950–1100℃. At 1150℃,the eutectic microstructure of M_(3)B_(2)+ γ was formed due to the dissolution of M_(3)B_(2), which caused macroscopic cracking of the deformed sample. Additionally, the deformation temperature and the strain rate had little effect on the size and volume fraction of M_(3)B_(2). Besides, discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX) were found in the deformed microstructure, while the former was dominant. Within the test range of this work, the dynamic recrystallization(DRX) fraction of the deformed composites was high due to the bulging nucleation of numerous interfaces. The DRX grain size increased with increasing deformation temperature or decreasing strain rate. Texture analysis showed that the deformation texture of //compression direction RD existed in the matrix when the deformation temperature was below 1100℃, and the texture type became //RD at 1100℃. Additionally, it was also found that the //RD texture was formed in M3B2under the strain rates of 0.1 and 0.01 s^(-1).

关键词： GH3536 alloy matrix composites powder metallurgy hot deformation behavior microstructure evolution

Fatigue Crack Initiation and Propagation Dominated by Crystallographic Factors in TiB/near α-Ti Composite

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 763-776页

作者： Fanchao Meng Rui Zhang Shuai Wang Fengbo Sun Run Chen Lujun Huang Lin Geng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China Waikato Centre for advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton 3240New Zealand State key laboratory of advanced welding and Joining Harbin Institute of TechnologyHarbin 150001China

Discontinuously reinforced titanium matrix composites(DRTMCs)with a network structure have been extensively researched due to their superior combination of strength and ***,their fatigue performance has remained *** order to elucidate the fatigue behavior of DRTMCs,a tension-tension fatigue test was performed on a TiB/nearα-Ti composite with network *** results showed that the variability of fatigue lifetime increased as the stress level *** analysis indicated that fatigue crack initiation was associated with facet formation,while the subsequent propagation was hindered by the network structure comprising TiB whiskers and *** characterization further revealed that facets formed due to a combination of shear and normal *** reduction in fatigue lifetime was attributed to an increase in the effective slip length,which was influenced by the orientation of grains near the crack-initiation sites toward basal slip in the life-limiting *** in situ observation suggested that the crack initiation was facilitated by both basal and prismatic slip ofα-Ti as well as fracture of *** propagation was found to be associated with basal and prismatic slip systems with high Schmid factors,regardless of whether the crack was intergranular or intragranular.

关键词： Titanium matrix composite TiBw Fatigue lifetime variability Crack initiation Crack propagation

Topological pseudospin switcher:Mechanism and acoustic realization

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 46-53页

作者： Jia-He Chen Yiyin Chen Yaoqieyu Song Yongxu Xu Xinrong Li Jingsong Wang Jiawei He Jiaxu Qu Zheng Li Xiaofei Li Wenqiang Lin Jiannan Chen Caixing Fu Zhi Hong Hang School of Physical Science and technology&Collaborative Innovation Center of Suzhou Nano Science and technology Soochow UniversitySuzhou 215006China Institute for advanced Study Soochow UniversitySuzhou 215006China provincial key lab of Thin Films Soochow UniversitySuzhou 215006China

The control of the pseudospin of sound wave has attracted increasing attention in recent *** the finite-size effect of topological acoustics,we successfully construct an H-shaped acoustic topological pseudospin switcher that sound wave energy can be easily switched through different *** interesting phenomenon of pseudospin flipping is numerically and experimentally demonstrated.A quantitative interference theory is proposed that the constructive and destructive interference of pseudospin states leads to pseudospin flipping and preserving in multiple *** verify the key parameters of the design,including the length of the passage and its interface state dispersion,and the theory can be extended to other topology acoustics and photonics ***,the tunable topological sonic crystal we use provides adjustable convenience to pseudospin switcher *** pseudospin switching behavior offers an efficient method to control the acoustic topological edge state transport,which has great potential in versatile applications,such as integrated acoustics,acoustic security,and information processing.

关键词： topological acoustics realization

Molecular-level proton acceptor boosts oxygen evolution catalysis to enable efficient industrial-scale water splitting

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Green Energy & Environment 2024年第2期9卷 344-355页

作者： Yaobin Wang Qian Lu Xinlei Ge Feng Li Le Chen Zhihui Zhang Zhengping Fu Yalin Lu Yang Song Yunfei Bu jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment technology(CICAEET) Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control(AEMPC)UNIST-NUIST Energy and Environment Jointed Lab(UNNU)School of Environmental Science and TechnologyNanjing University of Information Science and Technology(NUIST)219 NingliuNanjing210044China laboratory of advanced Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsFudan University220 HandanShanghai200433China jiangsu key laboratory of advanced Materials and technology School of Petrochemical EngineeringChangzhou University1 GehuChangzhou213164China Anhui laboratory of advanced Photon Science and technology University of Science and Technology of China(USTC)96 JinzhaiHefeiAnhui 230026China School of Chemistry and Chemical Engineering Nanjing University of Science and Technology200 Xiaolingwei210094China

Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be ***,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water ***-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline *** on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the *** use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.

关键词： Oxygen evolution reaction Nanofiber Water splitting Proton acceptor Perovskite

Thermal and Magnetic Dual-Responsive Catheter-Assisted Shape Memory Microrobots for Multistage Vascular Embolization

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Research 2024年第3期2024卷 529-543页

作者： Qianbi Peng Shu Wang Jianguo Han Chenyang Huang Hengyuan Yu Dong Li Ming Qiu Si Cheng Chong Wu Mingxue Cai Shixiong Fu Binghan Chen Xinyu Wu Shiwei Du Tiantian Xu Guangdong provincial key lab of Robotics and Intelligent Systems Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina University of Chinese Academy of Sciences BeijingChina Department of Neurosurgery South China HospitalMedical SchoolShenzhen University.ShenzhenChina The key laboratory of Biomedical Imaging Science and System Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenChina.

Catheters navigating through complex vessels,such as sharp turns or multiple U-turns,remain challenging for vascular ***,we propose a novel multistage vascular embolization strategy for hard-to-reach vessels that releases untethered swimming shape-memory magnetic microrobots(SMMs)from the prior catheter to the vessel ***,made of organo-gel with magnetic particles,ensure biocompatibility,radiopacity,thrombosis,and fast thermal and magnetic *** SMM is initially a linear shape with a 0.5-mm diameter at 20°C inserted in a *** transforms into a predetermined helix within 2 s at 38°C blood temperature after being pushed out of the catheter into the *** enable agile swimming in confined and tortuous vessels and can swim upstream using helical propulsion with rotating magnetic ***,we validated this multistage vascular embolization in living rabbits,completing 100-cm travel and renal artery embolization in 2 *** 4 weeks,the SMMs maintained the embolic position,and the kidney volume decreased by 36%.

关键词： turns maintained travel

Highly selective electrosynthesis of 3,4-dihydroisoquinoline accompanied with hydrogen production over three-dimensional hollow CoNi-based microarray electrocatalysts

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Nano Research 2024年第4期17卷 2509-2519页

作者： Yu Xin Liyu Chen Yingwei Li Kui Shen Guangdong provincial key lab for Green Chemical Product technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State key laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Electrocatalytic oxidation reaction of biomass-based derivatives is an excellent candidate to replace water oxidation for obtaining both value-added products and hydrogen(H_(2)),but the exploration of competent electrocatalysts is still highly ***,two new types of three-dimensional self-supported hollow microarrays containing CoNi layered double hydroxide(CoNi-LDH)and N-doped carbon nanosheets decorated with CoNi alloyed nanoparticles(CoNi-NC)on carbon cloth(CC)are prepared,which are further used as efficient electrocatalysts for tetrahydroisoquinoline(THIQ)electrooxidation and hydrogen evolution reaction(HER),*** demonstrate that the Co-modulated electronic environment for Ni(II)/Ni(Ⅲ)redox-looping in CoNi-LDH is the main factor to boost the selectivity of 3,4-dihydroisoquinoline(DHIQ)for the indirect electrooxidation process of *** functional theory(DFT)calculations reveal that the Ni(Ⅲ)/Co(Ⅲ)dual sites of CoNi-LDH exhibit enhanced adsorption for THIQ but poorer adsorption for DHIQ compared to pure Co(Ⅲ)or Ni(Ⅲ).Therefore,the Ni(Ⅲ)/Co(Ⅲ)dual sites can effectively inhibit the peroxidation of DHIQ to isoquinoline(IQ)over CoNi-LDH,thus improving the selectivity of DHIQ to nearly 100%,much higher than that of its pure Ni ***,CC@CoNi-NC can deliver high HER activity with low overpotential(40 mV@10 mA·cm^(-2))and high exchange current density(3.08 mA·cm^(-2)).Impressively,the assembled flow-cell device with CC@CoNi-LDH anode and CC@CoNi-NC cathode only requires low cell voltage and electricity consumption of 1.6 V and 3.50 kWh per cubic meter of H_(2)(@25 mA·cm^(-2)).

关键词： highly selective electrosynthesis dihydroisoquinolines hydrogen evolution reaction metal-organic frameworks hollow microarrays