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Experimental methods for determination of mechanical behaviors of materials at high temperatures via the split Hopkinson bars

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Acta Mechanica Sinica 2020年第6期36卷 1275-1293,I0003页

作者： Q.B.Dou K.R.Wu T.Suo C.zhang X.guo y.z.guo W.G.guo y.L.Li School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Joint International Research Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China State Key Laboratory for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Full understanding of the thermomechanical behaviors of materials at high strain rates and high temperatures are of great importance from not only scientific meaning but also practical value in engineering structure design and safety *** efforts have been made for abilities of operation the split Hopkinson bars,the most popular technique for experimental determination of mechanical behaviors of materials over the strain rates from 10^2 to 10^4 s^−1 over the past 70 years,at high temperatures since 1960s.A review of experiment work is presented in this paper to give an overview of the development of experimental techniques at high temperatures based on Hopkinson bar *** principles of the split Hopkinson bar requires the loading bars avoiding temperature gradient or keeping relatively low temperature when performing high temperature *** such as performing temperature gradient corrections,rapid heating or using special designed automatically assembled systems were proposed by researchers to enable the operation of the split Hopkinson bars at temperature as high as ***,to the application of high speed photographic technique for capturing the dynamic deformation process of the specimen in high temperature Hopkinson bar testing,some key issues of eliminating the strong thermal radiation induced lights oversaturation and de-blurring of images due to insufficient exposure at high temperature and high strain rate condition,as well as fabrication of high contrast speckle pattern for high temperature digital image correlation measurement were also *** technique can now enable the split Hopkinson bar testing to be performed at high temperature up to 1873 K under the loading conditions of compression or tension with the in situ observation and full field measurement of deformation as *** paper concludes with summaries of the most important achievements and highlighting of the prospects,trends and remaining challenge

关键词： Mechanical behaviors Split Hopkinson bar High strain rate High temperature

Dynamic mechanical Response of two fiber-reinforced composites

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Dynamic mechanical Response of two fiber-reinforced composit...

ELECTRON-COOLING FOR THE INITIAL COMMISSIONING OF CSR

The 16th Annual Conference of Hong Kong Society of Theoretical and Applied Mechanics 2012、The 1st Mainland-Hong Kong youth Forum on Mechanics 2012、The 8th Shanghai-Hong Kong Forum on Mechanics and Its Application 2012

作者： y.z.guo X.Chen z.zeng y.L.Li School of Aeronautics Northwestern Polytechnical University

The mechanical behavior of two fiber-reinforced composites,i.e.,CF3031/Qy8911 and EW100A/BA9916,under dynamic loadings were carefully studied by using split Hopkinson pressure bar(SHPB) *** results show that most of the stress strain curves of both of the two composites are not monotonous but exhibite double-peak shape. The deformation as well as fracture characteristics of the composites under dynamic loadings were captured by using high speed *** photoes indicate that two different failure mechanisms work during dynamic fracture *** first one is the overall shear,which occurs along the path 45°to the loading *** second one is the cleavage between the fiber and the matrix(see figure 1).The competition between these two mechanisms determines the deformation behavior of the *** the overall shear dominates,the stress increase monotonously with increasing strain until ***,if the cleavage mechanism dominates,the double peak character shows itself in the stress-strain curves.

关键词： Dynamic mechanical Response of two fiber-reinforced composites

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ELECTRON-COOLING FOR THE INITIAL COMMISSIONING OF CSR

Microstructural evolution during the progressive transformation-induced plasticity effect in a Fe-0.1C-5Mnmedium manganese steel

第三届全国加速器技术学术交流会

作者： J.W.Xia W.L.zhan y.J.yuan X.D.yang y.Liu y.He J.C.yang L.J.Mao z.z.zhou R.S.Mao T.C zhao z.Xu C.X.Wang y.P.yang M.T.Song D.Q.Gao X.T.yang J.H.zhang P.yuan L.z.Ma K.D.Man y.Q.yang y.z.guo W.M.Qiao N.Jin G.Q.Xiao H.W.zhao J.H.zhen J.X.Wu y.W.Su X.H.Cai and CSR group Institute of Modern Physics(IMP),Chinese Academy of Sciences(CAS)

Since the beginning of 2006 the heavy ion cooler-storage-ring(CSR)system in Lanzhou has been into the stage of the initial *** heavy ion beams from the cyclotron system of HIRFL will be injected into the first ring CSRm,accompanying with the accumulation,e-cooling and acceleration,finally extracted to the experiment ring CSRe for internal-target *** the winter of 2006,the electron-cooling was first

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 369-379页

作者： Mei zhang Wenhao Li yangfei Chen yang Jiang Xiaofei guo Han Dong School of Materials Science and Engineering Shanghai UniversityShanghai 200444China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200444China

The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile ***-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation *** findings were discussed with the local strain measurements via digital image *** results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of *** small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier *** volume fraction of RA gradually decreased from 26.8%to 8.2%prior to *** the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.

关键词： medium-Mn steel retained austenite progressive transformation-induced plasticity effect local strain fracture initiation

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New types of singular solutions of conformal Q-curvature equations

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Acta Mathematica Sinica,English Series 2025年

作者： zongming guo zhongyuan Liu Fangshu Wan Department of Mathematics Henan Normal University School of Mathematics and Statistics Henan University School of Mathematical Sciences Anhui University

We construct radial and non-radial singular solutions u ∈ C4（By） with a non-removable singular point x = 0 for the conformal Q-curvature equation:■where B = {x ∈ R4: |x| D0≥ 0, and satisfying ■Moreover, deta...

We construct radial and non-radial singular solutions u ∈ C4（By） with a non-removable singular point x = 0 for the conformal Q-curvature equation:■where B = {x ∈ R4: |x| y, we can construct two different types of singular solutions u ∈ C4（By） of（0.1）, satisfying ■for some D0 ≥ 0 and any D > D0≥ 0, and satisfying ■Moreover, detailed asymptotic expansions near x = 0 of these radial and non-radial singular solutions can be established. As an application, we can also obtain the existence of two types of solutions u ∈ C4（R4■） to the problem ■ satisfying |x|-2u（x） →-D y as |x| → ∞ for some D0≥ 0 and any D > D0, and satisfying u（x） = o（|x|2） uniformly as |x| → ∞.

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The linear self-attracting diffusion driven by the weighted-fractional Brownian motion II: The parameter estimation

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Science China Mathematics 2025年

作者： Litan yan Rui guo Wenyi Pei Department of Statistics College of Science Donghua University School of Statistics and Mathematics Zhejiang Gongshang University

Let Ba,bbe a weighted-fractional Brownian motion with Hurst indexes a and b such that a>-1and 0≤b<1∧（1+a）.In this paper,we consider the linear self-attracting diffusion ■ interacting diffusion (see Cranston and L...

Let Ba,bbe a weighted-fractional Brownian motion with Hurst indexes a and b such that a>-1and 0≤by asymptotic ■ converges in distribution to the sum of the chi-square random variable with 1 degree of freedom and the random variable z1a,b.

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A Mn-porphyrinic metal–organic framework immobilizing glucose oxidase for combined photodynamic/chemodynamic/starvation therapy

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Tungsten 2025年第1期7卷 183-194页

作者： Xin-Ran Sun Hao-Ming yuan guo-Da zhang Chao Wang Shu-Juan Sun Peng-Fei Shi Shandong Provincial Key Laboratory of Detection Technology for Tumor Markers School of Chemistry and Chemical Engineering Linyi University

The combination of photodynamic therapy（PDT） and chemodynamic therapy（CDT） in tumor treatment has attracted considerable ***,tumor hypoxia and glutathione（GSH） overproduction in the tumor tissue restricted the progress of their ***,a Mn-porphyrinic metal-organic framework（Mn-TCPP） was constructed by the one-pot method and further used for immobilizing glucose oxidase（GOx） to obtain GOx@*** would rapidly exhaust endogenous glucose into hydrogen peroxide（H2O2） and gluconic acid,thus shutting off the energy supply of tumor cells for starvation ***-TCPP catalyzed H2O2to produce oxygen,regulating the hypoxic tumor microenvironment and in turn improving1O2generation under laser ***,Mn-TCPP can reduce reactive oxygen species consumption owing to the redox reaction between Mn3+and GSH,thus greatly enhancing ***,benefiting from GOx-mediated starvation therapy,Mn2+produced by Mn3+reduction can react with sufficient intracellular H2O2to generate ·OH with high cytotoxicity through a Fenton-like *** treatment by GOx@Mn-TCPP under laser irradiation in vitro,the cell viability of 4T1 and A549 tumor cells reached to 20%,reflecting GOx@Mn-TCPP could give full play to the advantages of PDT/CDT/starvation *** results in vivo demonstrated that GOx@Mn-TCPP mediated synergistic cascade therapy could significantly inhibit tumor growth and improve the therapeutic effect.

关键词： Chemodynamic therapy Immobilizing enzyme Metal–organic frameworks Photodynamic therapy Starvation therapy

Low‑Temperature Oxidation Induced Phase Evolution with Gradient Magnetic Heterointerfaces for Superior Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第1期17卷 191-204页

作者： zizhuang He Lingzi Shi Ran Sun Lianfei Ding Mukun He Jiaming Li Hua guo Tiande Gao Panbo Liu School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710129People’s Republic of China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China

Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase ***,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation *** results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial ***,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic ***,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon *** design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.

关键词： Magnetic heterointerfaces Phase evolution Interfacial polarization Magnetic coupling Electromagnetic wave absorption

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Numerical Modeling and Analysis of Grooved Surface Applied to Film Cooling

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Journal of Bionic Engineering 2011年第4期8卷 464-473页

作者： L. guo z. C. Liu y. y. yan z. W. Han Faculty of Engineering University of Nottingham Nottingham NG7 2RD UK Department of Internal Combustion Engine Jilin University Changchun 130022 P. R. China Key Laboratory of Bionic Engineering （Ministry of Education China） Jilin University Changchun 130022 P. R. China

In order to improve the efficiency of film cooling, numerical investigation was carried out to study the effects of different film-cooled plates on surface heat transfer. Both grooved and non-grooved surfaces were concerned. The modeling was per- formed using Fluent software with the adoption of Shear-Stress Transport （SST） k-ωmodel as the turbulence closure. The coolant was supplied by a single film cooling hole with an inclination angle of 30°. The Mach numbers for the coolant flow and the mainstream flow were fixed at 0 and 0.6, respectively. At three blowing ratios of 0.5, 1.0 and 1.5, the aerodynamic behaviour of the mixing process as well as the heat transfer performance of the film cooling were presented. The numerical results were validated using experimental data extracted from a benchmark test. Good agreements between numerical results and the ex- perimental data were observed. For the film cooling efficiency, it shows that both local and laterally averaged cooling effectiveness can be improved by the non-smooth surface at different blowing ratios. Using the grooved surface, the turbulence intensity upon the plate can be reduced notably, and the mixing between the two flows is weakened due to the reduced turbu lence level. The results indicate that the cooling effectiveness of film cooling can be enhanced by applying the grooved surface.

关键词： film cooling non-smooth surface cooling effectiveness grooved structure blowing ratio