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spherical cavity-expansion model for penetration of reinforced-concrete targets

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Acta Mechanica sinica 2019年第4期35卷 535-551页

作者： y.J.Deng W.J.song X.W.Chen Institute of systems Engineering China Academy of Engineering PhysicsP.O.Box 919-416Mianyang 621999China shock and Vibration of Engineering Materials and structures Key Laboratory of sichuan Province Mianyang 621000China Department of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621000China Department of Mechanics and Engineering science College of EngineeringPeking UniversityBeijing 100871China Advanced Research Institute for Multidisciplinary science Beijing Institute of TechnologyBeijing 100081China state Key Lab of Explosion science and Technology Beijing Institute of TechnologyBeijing 100081China

The feature of reinforcing bars is introduced into dynamic cavity-expansion theory. Based on the elastic-plastic response penetration model of plain (i.e., unreinforced) concrete (Forrestal and Tzou, 1997), a dynamic spherical cavity-expansion penetration model for reinforced-concrete targets is developed with consideration of the circumferential restriction effect derived from reinforcing bars in the crushed region. The theoretical solution and simplified calculation formula for the cavity radial stress in incompressible and compressible reinforced concrete are obtained by introducing a reinforcement ratio as the volume fraction of rebars in the concrete target. A damping function is presented to describe the restriction effect of a single layer of reinforcing bars on the surrounding concrete, thus establishing a model to calculate the penetration resistance of multilayer reinforced-concrete targets. Compared with test data for the penetration depth, this model considering the circumferential restriction effect produces better results compared with the existing theory.

关键词： Dynamic cavity-expansion theory Reinforced concrete Penetration resistance Reinforcement ratio

PREPARATION AND CORROsION REsIsTANCE OF NiP/TiO_2 COMPOsITE FILM ON CARBON sTEEL IN sULFURIC ACID sOLUTION

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Acta Metallurgica sinica(English Letters) 2006年第2期19卷 117-123页

作者： L.Z. song s.Z. song J. Zhao school of Environment ＆ Chemical Engineering Yanshan University Qinhuangdao 066004 China school of Materials science and Engineering Tianjin University Tianjin 300072 China

A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, EsEM （environmental scanning electron microscopy） and EIs （electrochemical impedance spectroscopy） measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2sO4 solution. The element valence of the composite film was characterized by XPs （X-ray photoelectron spectroscopy） spectrum, and an anticorrosion mechanism of the composite film was discussed.

关键词： electroless plating and sol-gel composite process artificial neural network NiP/TiO2 composite film corrosion resistance

soft x-ray tomographic reconstruction of Heliotron J plasma for the study of magnetohydrodynamic equilibrium and stability

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Plasma science and Technology 2019年第6期21卷 72-78页

作者： s PUROHIT y sUZUKI s OHDACHI s yAMAMOTO sOKENDAI The Graduate University for Advanced Studies Toki Gifu 509-5292 Japan National Institute for Fusion science Toki Gifu 509-5292 Japan Institute of Advanced Energy Kyoto University Gokasho Uji Kyoto 611-0011 Japan

The preparation for an experimental soft x-ray tomography study on the Heliotron J (H-J) machine is carried out,with the objectives of evaluating the capability of the current soft x-ray tomographic system in terms of the identification of different mode structures and their poloidal rotation,and the axis shift with different plasma and machine parameters,and fixing the physics goals for the experimental *** preparations were carried out via a simulated soft x-ray data set arising from different plasma conditions,such as magnetic islands,low beta and high *** x-ray tomography (sXT) is performed by the discrete pixel method including singular value decomposition and Phillips-Tikhonov regularization,to obtain clear and smooth *** H-J soft x-ray tomography results from simulated soft x-rays for the equilibrium H-J plasma sensed the magnetic axis shift clearly and an estimate was also *** reconstruction for mode structure m =1/n =1 was obtained along with the realization of the poloidal rotation of the *** reconstruction for the m =2/n =1 mode was not very clear for the current soft x-ray diagnostic *** mode identification was not possible due to the lack of *** sXT from the current soft x-ray diagnostic on H-J,the magnetic axis shift can be estimated and the m =1/n =1 mode can be *** of higher poloidal modes is difficult with the current design.

关键词： Heliotron J tomography soft x-ray magnetohydrodynamics

Effect of Temperature on Material Transfer Behavior at Different stages of Friction stir Welded 7075-T6 Aluminum Alloy

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Journal of Materials science & Technology 2013年第10期29卷 955-960页

作者： s.D.Ji y.y.Jin y.M.yue s.s.Gao y.X.Huang L.Wang Faculty of Aerospace Engineering Shenyang Aerospace University state Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

In this work, the morphologies of weld of 7075-T6 aluminum alloy via friction stir welding （FsW） were analyzed by optical microscopy, the temperature field was attained by numerical simulation, and the effect of temperature on material transfer behavior in the thermal-mechanical affected zone （TMAZ） at different stages was mainly investigated. The FsW process consists of three stages. It is very interesting to find that the maximum transfer displacement of material appears at the final stage of welding process, then at the stable stage and at the initial stage, which results from the difference of peak temperatures at different stages. At any stage, the material in TMAZ near the surface of weld transfers downwards, the material in the middle of weld moves upwards and the material near the bottom of weld hardly moves. In any cross section of weld, the largest transfer displacement of material appears in the middle of weld. The increase of rotational velocity and the decrease of welding speed are both beneficial to the transfer displacement of material in the middle of weld.

关键词： Friction stir welding 7075-T6 aluminum alloy Thermal-mechanical affected zone Material transfer Numerical simulation

Temperature Effects on the Microstructures of Mg-Gd-y Alloy Processed by Multi-direction Impact Forging

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Acta Metallurgica sinica(English Letters) 2020年第2期33卷 243-251页

作者： s.s.A.shah D.Wu R.s.Chen G.s.song school of Material science and Engineering Anhui University of Technology The Group of Magnesium Alloys and Their Applications Institute of Metal ResearchChinese Academy of Sciences

A high strain rate multi-directional impact forging(MDIF) was applied to a solutionized Mg-Gd-y-Zr alloy in the temperature range of 350-500℃.Results demonstrate that the dominant deformation mode is twinning at a temperature below 400℃,whereas at a medium temperature of 450℃ considerable continuous dynamic recrystallization was promoted by{10-12} extension *** a higher temperature of 500℃,twinning activation was *** DRX grains were observed but their sizes were much bigger than those resulting from the MDIFed 50 passes at 450℃,which are ascribed to the larger grain boundary mobility and atomic diffusion at 500℃.Moreover,a non-basal weak texture was gained afterward MDIF at each temperature,which is credited to the MDIF process and the minor strain applied in each pass.

关键词： Magnesium alloys Twinning Dynamic recrystallization Forging Texture

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汉末三国的军师

南都学坛 2025年第1期45卷 1-12页

作者：宋杰首都师范大学历史学院北京100089

“军师”是为君主将帅谋划作战事务的文职官员,周代尊称为“师”,两汉之际始称“军师”。汉末三国曹操的首位军师是周,后来荀攸作为军师跟随他征伐中原,屡立奇功。曹操被封魏公后,设立有中军师、前军师、左右军师等,文帝以降又在中军和... 详细信息

“军师”是为君主将帅谋划作战事务的文职官员,周代尊称为“师”,两汉之际始称“军师”。汉末三国曹操的首位军师是周,后来荀攸作为军师跟随他征伐中原,屡立奇功。曹操被封魏公后,设立有中军师、前军师、左右军师等,文帝以降又在中军和边防外军都督属下置军师,参赞军务,代表朝廷监督主将。蜀汉刘备先后任命诸葛亮为军师中郎将、军师将军,有带兵的权力。诸葛亮执政后设前军师、中军师等荣誉官衔,到他死后逐渐取消。孙吴长期未设军师,曾经颁授的也只是荣誉性的附加职衔,起不到为君主参议军事的作用。吴、蜀军师的虚设与消亡,与其人才匮乏有密切关系。

关键词：师军师祭酒周荀攸诸葛亮

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Multi-place physics and multi-place nonlocal systems

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Communications in Theoretical Physics 2020年第5期72卷 120-132页

作者： s y Lou school of Physical science and Technology Ningbo UniversityNingbo315211China

Multi-place nonlocal systems have attracted attention from many *** this paper,we mainly review the recent progresses on two-place nonlocal systems(Alice-Bob systems)and four-place nonlocal ***-place systems can firstly be derived from many physical problems by using a multiple scaling method with a discrete symmetry group including parity,time reversal,charge conjugates,rotations,field reversal and exchange *** nonlocal systems can also be derived from the symmetry reductions of coupled nonlinear systems via discrete symmetry *** the other hand,to solve multi-place nonlocal systems,one can use the symmetry-antisymmetry separation approach related to a suitable discrete symmetry group,such that the separated systems are coupled local *** using the separation method,all the known powerful methods used in local systems can be applied to nonlocal *** this review article,we take two-place and four-place nonlocal nonlinear schr?dinger(NLs)systems and Kadomtsev-Petviashvili(KP)equations as simple examples to explain how to derive and solve *** types of novel physical and mathematical points related to the nonlocal systems are especially emphasized.

关键词： multi-place physics multi-place nonlocal systems symmetries integrable systems parity and time reversal soliton theory classical prohibitions

Neumann＇s method for boundary problems of thin elastic shells

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Applied Mathematics and Mechanics(English Edition) 2017年第4期38卷 543-556页

作者： y. s. NEUsTADT Department of Civil Engineering Samara State Architectural and Building University Samara 443001 Russia

The possibility of using Neumann＇s method to solve the boundary problems for thin elastic shells is studied. The variational statement of the static problems for the shells allows for a problem examination within the distribution space. The convergence of Neumann＇s method is proven for the shells with holes when the boundary of the domain is not completely fixed. The numerical implementation of Neumann＇s method normally requires significant time before any reliable results can be achieved. This paper suggests a way to improve the convergence of the process, and allows for parallel computing and evaluation during the calculations.

关键词： boundary problem thin elastic shell theory Neumann's method variational principle Korn's inequality distribution embedding theorem Green tensor

Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.W.Wi y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

We investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths