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On B(5,20)2-Groups

Algebra Colloquium 2024年第3期31卷 429-440页

作者： E.A.Alhassan y.L.Tan y.li School of Mathematical Sciences Jiangsu UniversityZhenjiangJiangsu 212013China Department of Mathematics Brock UniversitySt.CatharinesOntario L2S 3A1Canada

A finite group G is said to be a B(n,k)group if for any n-element subset[a_(1),…,a_(n)]of G,|{a_(i)a_(j)|1≤i,j≤n}|≤*** is of interest to characterize the structure of B(n,k)groups for n(n+1)/2≤k≤n^(2)-*** B(5,k)groups for 15≤k≤19 have been investigated by several *** this paper,we give a complete characterization of B(5,20)2-groups by showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n,k)groups small squaring property central extension GAP

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3y-1Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.Lv H.L.Ge q.q.Jin X.H.Shao y.T.Zhou B.Zhang X.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering Research Center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation Hardening Precipitates In-situ TEM

Reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of liBH_(4) by novel waxberry-like nano-additive assembled from ultrafine Fe_(3)O_(4) particles

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Journal of Materials Science & Technology 2024年第6期173卷 63-71页

作者： S.Wang M.H.Wu y.y.Zhu Z.L.li y.X.yang y.Z.li H.F.liu M.X.Gao Department of Material Science Shenzhen MSU-BIT UniversityShenzhen 518172China State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Resources Utilization and Rare Earth Development State Key Laboratory of Rare Metals Separation and Comprehensive UtilizationGuangdong Provincial Key Laboratory of Rare Earth Development and ApplicationGuangdong Academy of SciencesGuangzhou 510650China Institute of Science and Technology for New Energy Xi’an Technological UniversityXi’an 710021China National Supercomputing Center in Shenzhen Shenzhen 518055China

liBH_(4) containing 18.5 wt.%H_(2) is an attractive high-capacity hydrogen storage material,however,it suffers from high operation temperature and poor ***,a novel and low-cost bifunctional additive,waxberry-like Fe_(3)O_(4) secondary nanospheres assembled from ultrafine primary Fe_(3)O_(4) nanoparticles,is synthesized,which exhibits significant destabilization and bidirectional catalyzation towards(de)hydrogenation of liBH_(4).With an optimized addition of 30 wt.% waxberry-like Fe_(3)O_(4),the system initiated dehydrogenation below 100℃ and released a total of 8.1 wt.%H_(2) to 400℃.After 10 cycles,a capacity retention of 70% was achieved,greatly superior to previously reported oxides-modified *** destabilizing and catalyzing mechanisms of waxberry-like Fe_(3)O_(4) on liBH_(4) were systematically analyzed by phase and microstructural evolutions during dehydrogenation and hydrogenation cycling as well as density functional theory(DFT)*** present work provides new insights in developing advanced nano-additives with unique structural and multifunctional designs towards liBH4 hydrogen storage.

关键词： liBH_(4) Hydrogen storage Waxberry-like Fe_(3)O_(4) Destabilization Catalysis

对比增强MRI预测局部进展期直肠癌新辅助放化疗后的T再分期

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国际医学放射学杂志 2023年第1期46卷 104-104页

作者： q.y.Lu Z.Guan X.y.Zhang X.T.li R.J.Sun q.y.li 陈红

摘要直肠癌新辅助放化疗(NCRT)后准确再分期,对于局部切除病人的选择至关重要。常规MRI中结合T2WI和DWI方法在再分期方面存在一定的局限性。目的确定对比

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Generation of polarized electron beams through self-injection in the interaction of a laser with a pre-polarized plasma

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High Power Laser Science and Engineering 2024年第3期12卷 62-68页

作者： L.R.yin X.F.li y.J.Gu N.Cao q.Kong M.Büscher S.M.Weng M.Chen Z.M.Sheng Key Laboratory of Nuclear Physics and Ion-beam Application(MoE) Institute of Modern PhysicsDepartment of Nuclear Science and TechnologyFudan UniversityShanghaiChina State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghaiChina SANKEN(Institute of Scientific and Industrial Research) Osaka UniversityOsakaJapan Sichuan Research Institute Shanghai Jiao Tong UniversityChengduChina Peter Grünberg Institut(PGI-6) Forschungszentrum JülichJülichGermany Institut für Laser-und Plasmaphysik Heinrich-Heine-Universität DüsseldorfDüsseldorfGermany Key Laboratory for Laser Plasmas(MoE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghaiChina Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghaiChina Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghaiChina

Polarized electron beam production via laser wakefield acceleration in pre-polarized plasma is investigated by particlein-cell *** evolution of the electron beam polarization is studied based on the Thomas±Bargmann±Michel±Telegdi equation for the transverse and longitudinal self-injection,and the depolarization process is found to be influenced by the injection *** the case of transverse self-injection,as found typically in the bubble regime,the spin precession of the accelerated electrons is mainly influenced by the ***,in the case of longitudinal injection in the quasi-1D regime(for example,*** et al.,***.110,135002(2013)),the direction of electron spin oscillates in the laser *** the electrons move around the laser axis,the net influence of the laser field is nearly zero and the contribution of the wakefield can be ***,an ultra-short electron beam with polarization of 99%can be obtained using longitudinal self-injection.

关键词： laser wakefield acceleration longitudinal self-injection particle-in-cell simulation polarized electron beam

Rescattering of stimulated Raman side scattering in nonuniform plasmas

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Matter and Radiation at Extremes 2024年第5期9卷 68-76页

作者： S.Tan q.Wang y.Chen W.B.yao C.Z.Xiao J.F.Myatt School of Physics and Electronics Hunan UniversityChangsha 410082China Institute of Applied Physics and Computational Mathematics Beijing 100094China School of Electrical and Information Engineering Anhui University of Science and TechnologyHuainanAnhui 232001China Department of Electrical and Computer Engineering University of Alberta9211116 St.NWEdmontonAlberta T6G 1H9Canada

Rescattering of stimulated Raman side scattering(SRSS)is observed for the first time via two-dimensional(2D)particle-in-cell(PIC)*** construct a theoretical model for the rescattering process,which can predict the region of occurrence of mth-order SRSS and estimate its *** rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion *** electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order SRSS,but there is no cascade acceleration to produce superhot *** studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and important processes in inertial confinement fusion.

关键词： nonuniform acceleration scattering

Electromagnetic Performance Analysis of Variable Flux Memory Machines with Series-magnetic-circuit and Different Rotor Topologies

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 3-11页

作者： qiang Wei Z.q.Zhu yan Jia Jianghua Feng Shuying Guo yifeng li Shouzhi Feng Department of Electronic and Electrical Engineering The University of SheffieldSheffield S13JDU.K. IEEE the CRRC Zhuzhou Institute Company Ltd. Zhuzhou 412001China

In this paper,the electromagnetic performance of variable flux memory(VFM)machines with series-magnetic-circuit is investigated and compared for different rotor *** on a V-type VFM machine,five topologies with different interior permanent magnet(IPM)arrangements are evolved and optimized under same *** on two-dimensional(2-D)finite element(FE)method,their electromagnetic performance at magnetization and demagnetization states is *** reveals that the iron bridge and rotor lamination region between constant PM(CPM)and variable PM(VPM)play an important role in torque density and flux regulation(FR)***,the global efficiency can be improved in VFM machines by adjusting magnetization state(MS)under different operating conditions.

关键词： Memory machine Permanent magnet Rotor topologies Series magnetic circuit Variable flux

Precipitation transformation pathway and mechanical behavior of nanoprecipitation strengthened Fe-Mn-Al-C-Ni austenitic low-density steel

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Journal of Materials Science & Technology 2024年第7期174卷 157-167页

作者： y.F.An X.P.Chen L.Mei P.Ren D.Wei W.q.Cao College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Guangxi Engineering Research Center for Characteristic Metallic Powder Materials School of Electronic EngineeringGuangxi University of Science and TechnologyLiuzhou 545006China Central Iron&Steel Research Institute Beijing 100081China

Precipitation strengthening has been widely adopted in austenitic low-density steel owing to excellent hardened *** approach generally employs the coherentκ′carbides and non-coherent B2 *** the precipitation transformation pathway is decisive for further optimizing the microstructures under specific engineering ***,the detailed precipitation sequence of Fe-28Mn-11Al-1C-5Ni(wt%)austenitic low-density steel as well as its influence on mechanical prop-erties during aging process is systematically *** results reveal that nano-sizedκ′carbides domains(2 nm)exist in the solution-treated *** aging at 500℃for 1 h,the cuboidalκ′carbides(15-20 nm)uniformly disperse in austenite ***,after aging at 700℃for 15 min,the coarsenκ′carbides(30-35 nm)inhomogeneously distribute and align preferentially along the〈100〉***,extending the aging time to 60 min,the needle-type B2 particles replace theκ′carbides due to the enrichment of Ni elements at the phase boundaries among the austenite andκ′*** aging at 900℃,κ′carbides entirely dissolve into the austenite matrix,and the intragranular B2 particles are the sole precipitates in the austenite matrix and follow the K-S orientation relationship with *** work hardening capability seriously deteriorates due to the shearing ofκ′carbides by gliding *** the intragranular B2 particles preserve excellent work hardening rate by dislocations bow-out *** present work is meaningful for guiding the design of new generation dual-nano precipitation austenitic lightweight steel.

关键词： lightweight steel κ′-carbides B2 particles Work hardening capability

Transfer learning framework for multi-scale crack type classification with sparse microseismic networks

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International Journal of Mining Science and Technology 2024年第2期34卷 167-178页

作者： Arnold yuxuan Xie Bing qli Department of Civil and Environmental Engineering Western UniversityLondon N6A 3K7Canada

Rock fracture mechanisms can be inferred from moment tensors(MT)inverted from microseismic ***,MT can only be inverted for events whose waveforms are acquired across a network of *** is limiting for underground mines where the microseismic stations often lack azimuthal ***,there is a need for a method to invert fracture mechanisms using waveforms acquired by a sparse microseismic ***,we present a novel,multi-scale framework to classify whether a rock crack contracts or dilates based on a single *** framework consists of a deep learning model that is initially trained on 2400000+manually labelled field-scale seismic and microseismic waveforms acquired across 692 *** learning is then applied to fine-tune the model on 300000+MT-labelled labscale acoustic emission waveforms from 39 individual experiments instrumented with different sensor layouts,loading,and rock types in *** optimal model achieves over 86%F-score on unseen waveforms at both the lab-and *** model outperforms existing empirical methods in classification of rock fracture mechanisms monitored by a sparse microseismic *** facilitates rapid assessment of,and early warning against,various rock engineering hazard such as induced earthquakes and rock bursts.

关键词： Multi-scale Fracture processes Microseismic Acoustic emission Source mechanism Deep learning