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Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

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Defence Technology（防务技术） 2024年第1期31卷 580-593页

作者： Zheng-qing Zhou ze-chen Du Xiao Wang Hui-ling Jiang Qiang Zhou Yu-long zhang Yu-zhe Liu Pei-ze zhang Research Institute of Macro-Safety Science University of Science and TechnologyBeijing100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Mechanical Engineering Nantong UniversityNantong226019China China North Industry Advanced Technology Generalization Institute Beijing100089China China Academy of Ordnance Science China

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive *** this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were *** the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro *** addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the *** stress parameters of the observation points were obtained through an effective numerical *** mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro *** result shows that the generation and expansion of micro defects are related to the stress area(*** upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile ***,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(*** horizontal direction) were also *** was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decrea

关键词： Explosive load Quasi-cracking area Micro defects Steel plate Dynamic response Numerical simulation

Injection molding of highly filled microcrystalline cellulose/polycaprolactone composites with the aid of reversible Diels-Alder reaction

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Journal of Materials Science & Technology 2024年第3期170卷 246-254页

作者： ze Pu Wang WenHong Ruan MinZhi Rong MingQiu zhang Key Laboratory for Polymeric Composite and Functional Materials of MOE GD HPPC LabIGCMESchool of ChemistrySun Yat-Sen UniversityGuangzhou 510275China

To tackle the challenge of producing highly filled polymer composites using the traditional injection molding technique,which is characterized by the fairly high melt viscosity that makes mold filling difficult,the authors propose a solution based on dynamic covalent *** demonstrated by the proof-of-concept experiments,the 4-arm starshaped polycaprolactone(PCL)oligomers and microcrystalline cel-lulose(MCC)are crosslinked by the reversible Diels-Alder(DA)*** flowability of the compounds greatly decreases due to the dissociation of the intercomponent DA bonds at the retro-reaction tempera-ture,and the networked architecture is reconstructed during cooling as a result of the forward DA ***,the high-loading MCC fillers are well distributed in the matrix and covalently bonded to the nearby PCL,forming a striking contrast to the control in which linear PCL acts as the *** DA bonds crosslinked biodegradable PCL composites exhibit decent mechanical strength(20.7 MPa)even at the MCC fraction of 65 wt%,which is superior to those(5-12.2 MPa)of the highly filled PCL composites(with filler contents of 50-63.8 wt%)reported so *** proposed approach has sufficient expansibility for the fabrication of the highly filled polymer composites constructed by other types of matrix and fillers.

关键词： Polymer composites Microcrystalline cellulose Polycaprolactone Injection molding Dynamic reversible chemistry

Multiscale spatiotemporal meteorological drought prediction:A deep learning approach

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Advances in Climate Change Research 2024年第2期15卷 211-221页

作者： Jia-Li zhang Xiao-Meng HUANG Yu-ze SUN Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModellingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China

Reliable monitoring and thorough spatiotemporal prediction of meteorological drought are crucial for early warning and decision-making regarding drought-related *** utilisation of multiscale methods is effective for a comprehensive evaluation of drought occurrence and progression,given the complex nature of meteorological ***,the nonlinear spatiotemporal features of meteorological droughts,influenced by various climatological,physical and environmental factors,pose significant challenges to integrated prediction that considers multiple indicators and time *** address these constraints,we introduce an innovative deep learning framework based on the shifted window transformer,designed for executing spatiotemporal prediction of meteorological drought across multiple *** formulate four prediction indicators using the standardized precipitation index and the standard precipitation evaporation index as core methods for drought definition using the ERA5 reanalysis *** indicators span time scales of approximately 30 d and one ***-term indicators capture more anomalous variations,whereas long-term indicators attain comparatively higher accuracy in predicting future *** focus on the East Asian region,notable for its diverse climate conditions and intricate terrains,to validate the model's efficacy in addressing the complexities of nonlinear spatiotemporal *** model's performance is evaluated from diverse spatiotemporal viewpoints,and practical application values are analysed by representative drought *** results substantiate the effectiveness of our proposed model in providing accurate multiscale predictions and capturing the spatiotemporal evolution characteristics of *** of the four drought indicators accurately delineates specific facets of the meteorological drought ***,three representative drought events,namely flash drought,sustained drought and severe drought,

关键词： Meteorological drought Spatiotemporal prediction Multiscale Swim transformer Deep learning

Thermally Conductive,Healable Glass Fiber Cloth Reinforced Polymer Composite based onβ-Hydroxyester Bonds Crosslinked Epoxy with Improved Heat Resistance

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Chinese Journal of Polymer Science 2024年第5期42卷 643-654,I0009页

作者： Fang Chen Xiao-Yan Pang ze-Ping zhang Min-Zhi Rong Ming-Qiu zhang Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education GD HPPC LabIGCMESchool of ChemistrySun Yat-sen UniversityGuangzhou510275China Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Jieyang515200China

To simultaneously endow thermal conductivity,high glass transition temperature(Tg)and healing capability to glass fiber/epoxy(GFREP)composite,dynamic crosslinked epoxy resin bearing reversibleβ-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth(GFC@BNNSs).The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated ***,the GFC@BNNSs were impregnated with the mixture of lower concentration(3-glycidyloxypropyl)trimethoxysilane grafted BN micron sheets,3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride,which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical *** resultant GFREP composite containing less boron nitride particles(17.6 wt%)exhibited superior in-plane(3.29 W·m^(-1)·K^(-1))and through-plane(1.16 W·m^(-1)·K^(-1))thermal conductivities,as well as high Tg of 204℃(Tg of the unfilled epoxy=177℃).The reversible transesterification reaction enabled closure of interlaminar cracks within the composite,achieving decent healing efficiencies estimated by means of tensile strength(71.2%),electrical breakdown strength(83.6%)and thermal conductivity(69.1%).The present work overcame the disadvantages of conventional thermally conductive composites,and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application.

关键词： Thermally conductive composites Boron nitride High-temperature resistance β-Hydroxyl ester bond Healing

Fine Sand and Clay Sediment Acoustic Properties of the Novel Sediment Sample from the Arabian Sea:Experimental Investigations and Biot−Stoll Model Validation

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China Ocean Engineering 2024年第1期38卷 169-180页

作者： Shahabuddin SHAIKH HUANG Yi-wang zhang ze-chuan Habib Hussain ZUBERI National Key Laboratory of Underwater Acoustic Technology and College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed marine sediments from of Pakistan coastline of the Arabian *** measured physical parameters included mean grain size,mass density,bulk density,salinity,porosity,permeability,pore size and mineralogical *** properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transmission method and Fourier transform techniques was utilized to examine the sound propagation and absorption of novel seabed *** standard deviation of mean sound speed in fresh water was 0.75 m/s,and attenuation was observed in the range of 0.43 to 0.61 dB/*** mean sound velocity in sand and clay varied from 1706 to 1709 m/s and 1602 to 1608 m/s,*** average attenuation was observed at 80 to 93 dB/m in sandy sediments and from 31.8 to 38.6 dB/m in clayey *** velocity variation within sandy sediment is low,consistent with expected results,and smaller than the predicted ***,clay sediment exhibited a positive linear correlation and low sound speed *** increased linearly with frequency for both ***,the laboratory results were validated by using the Biot−Stoll *** dispersion of sound speed in sandy and clayey sediments was consistent with the predictions of the Biot−Stoll *** attenuation aligned more with Biot−Stoll model predictions due to improved permeability,tortuosity and pore size parameter fitting.

关键词： physical and acoustic characteristics marine sediments sound speed attenuation Biot−Stoll model

Static recrystallization behaviors and mechanisms of 7Mo super-austenitic stainless steel with undissolved sigma precipitates during double-stage hot deformation

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Journal of Iron and Steel Research International 2024年第2期31卷 475-487页

作者： Shi-guang Xu Jin-shan He Run-ze zhang Fu-cheng zhang Xi-tao Wang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing100083China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004HebeiChina Shandong Provincial Key Laboratory for High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Science)Jinan250353ShandongChina

Static recrystallization(SRX)behaviors and corresponding recrystallization mechanisms of 7Mo super-austenitic stainless steel were studied under different deformation *** order of influence of deformation parameters on static recrystallization behaviors,from high to low,is followed by temperature,first-stage strain and strain ***,the effect of holding time on static recrystallization behaviors is significantly controlled by *** addition,with the increase in temperature from 1000 to 1200°C,the static recrystallization mechanism evolves from discontinuous static recrystallization and continuous static recrystallization(cSRX)to metadynamic recrystallization and cSRX,and finally to *** cSRX exists at all *** is because high stacking fault energy(56 mJ m−2)promotes the movement of dislocations,making the deformation mechanism of this steel is dominated by planar slip of *** undissolved sigma precipitates promote static recrystallization through particle-stimulated ***,small strain-induced precipitates at grain boundaries hinder the nucleation of conventional SRX and the growth of recrystallized grains,while the hindering effect decreases with the increase in temperature.

关键词： 7Mo super-austenitic stainless steel Double-stage hot deformation Conventional static recrystallization Metadynamic recrystallization Strain-induced precipitation

Products of Commutator Ideals of Some Lie-admissible Algebras

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1875-1892页

作者： Ivan KAYGORODOV Farukh MASHUROV Tran Giang NAM ze Rui zhang CMA-UBI Universidade da Beira InteriorCovilhaPortugal Shenzhen International Center for Mathematics(SICM) Southern University of Science and TechnologyShenzhen 518055P.R.China Institute of Mathematics VAST18 Hoang Quoc VietCau GiayHanoiVietnam School of Mathematical Sciences South China Normal UniversityGuangzhou 510631P.R.China

In this article,we mainly study the products of commutator ideals of Lie-admissible algebras such as Novikov algebras,bicommutative algebras,and assosymmetric *** precisely,we first study the properties of the lower central chains for Novikov algebras and bicommutative *** we show that for every Lie nilpotent Novikov algebra or Lie nilpotent bicommutative algebra A,the ideal of A generated by the set{ab−ba|a,b∈A}is ***,we study properties of the lower central chains for assosymmetric algebras,study the products of commutator ideals of assosymmetric algebras and show that the products of commutator ideals have a similar property as that for associative algebras.

关键词： Novikov algebra bicommutative algebra assosymmetric algebra Lie nilpotent algebra

Description of martensitic transformation kinetics in Fe-C-X(X = Ni,Cr,Mn,Si) system by a modified model

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1026-1036页

作者： Xiyuan Geng Hongcan Chen Jingjing Wang Yu zhang qun Luo Qian Li State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Ansteel Beijing Research Institute Co. LtdBeijing 102211China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

Controlling the content of athermal martensite and retained austenite is important to improving the mechanical properties of high-strength steels,but a mechanism for the accurate description of martensitic transformation during the cooling process must be *** present,frequently used semi-empirical kinetics models suffer from huge errors at the beginning of transformation,and most of them fail to exhibit the sigmoidal shape characteristic of transformation *** describe the martensitic transformation process accurately,based on the Magee model,we introduced the changes in the nucleation activation energy of martensite with temperature,which led to the varying nucleation rates of this model during martensitic *** to the calculation results,the relative error of the modified model for the martensitic transformation kinetics curves of Fe-C-X(X = Ni,Cr,Mn,Si) alloys reached 9.5% compared with those measured via the thermal expansion *** relative error was approximately reduced by two-thirds compared with that of the Magee *** incorporation of nucleation activation energy into the kinetics model contributes to the improvement of its precision.

关键词： Fe-C-X system martensitic transformation kinetics curve semi-empirical model nucleation activation energy

Management and classification of the fracture of lateral process of talus:An overview and literature update

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World Journal of Clinical Cases 2024年第15期12卷 2487-2498页

作者： Chao-qun Wang Ulrich Stockle Sheng-Nan Dong Xu-Gui Li ze-Xi Ling Department of Traumatic Orthopedics The Affiliated Hospital of Wuhan Sports UniversityWuhan 430079Hubei ProvinceChina Center of Musculoskeletal Surgery Berlin CharitéMedical University HospitalBerlin 13353Germany

Fracture of the lateral process of the talus(FLPT)is uncommon in clinical practice and can be easily missed or *** recent years,as researchers from all over the world have further deepened their research on FLPT,there has been a breakthrough in the classification,and the methods and principles of clinical management have changed accordingly;however,there is still no standardized guideline for the diagnosis and management of FLPT,and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 *** this article,we review the clinical classification,classification-based therapeutic recommendations,and prognosis of FLPT,with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

关键词： Fracture of the lateral process of the talus Fracture of the talus Hindfoot injuries Intraarticular fracture Subtalar joint