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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

Evaluation of high-temperature tensile behavior for metal foils by a novel resistance heating assisted tensile testing system using samples with optimized structures

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Journal of Materials Science & Technology 2021年第35期94卷 216-229页

作者： qiu Zheng Tsuyoshi Furushima Department of Mechanical and Biofunctional Systems Institute of Industrial ScienceThe University of Tokyo4-6-1 KomabaMeguro 153-8505TokyoJapan

To evaluate the tensile behavior of metal foils by resistance heating(Rh)assisted tensile testing system accurately,this study proposed to embed a digital image correlation(DIC)system with laser speckles for the measurement of full-field strain ***,the sample structures were optimized to achieve uniform temperature and strain *** infrared camera was used to monitor the temperature *** samples instead of dog-bone shaped samples were proposed.A model for calculating the temperature distribution was established to optimize the sample *** parameters that influence the temperature distribution and tensile behavior were *** results,compared to the strain measured by a non-contact extensometer,the maximum deviation of the strain measured by DIC was less than 6%when the nominal strain was larger than *** is confirmed that the proposed tensile testing system is reliable for measuring the temperature and full-field strain *** shape influenced temperature distributions of smaller samples while it almost had no influence on the temperature distributions of larger *** temperature difference was not affected by the material type but by the sample *** proposed rectangular shape was validated to be feasible for Rh assisted tensile *** sample length was successfully optimized for a more uniform temperature distribution by the established *** the tensile deformation was not influenced by the sample shape,the temperature distribution resulted in a non-uniform strain distribution before achieving ultimate tensile *** effective sample length between two clamping jigs contributed to a more uniform temperature distribution and material deformation.A more accurate evaluation of high-temperature tensile behavior for metal foils can be achieved by the proposed Rh assisted tensile testing system using rectangular samples with an optimized structure.

关键词： high temperature Metal foil Resistance heating Sample structure Tensile behavior

Current situation and development trend of titanium metal industry in China

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 599-610页

作者： Guanzhou qiu Yufeng Guo School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

Titanium metal and alloy are key materials for technological development,which significantly promote the development of the hightech economy in *** consumption of high-end titanium materials and the developmental level of the titanium industry are important indexes of a country’s comprehensive ***,at present,the application amount and level of high-end titanium materials in China are limited by many factors,including the dependence of raw materials on imports,high processing cost,and structural imbalance of *** on the characteristics of titanium resources and the current situation of the titanium industry,the whole titanium industrial chain in China should be *** the quality of raw materials is important to produce low-cost,high-end titanium materials using titanium resources with high calcium and magnesium contents in the Panxi *** addition,the steel-titanium joint production is a vital step to reduce the processing cost of titanium ***,the consumption structure of titanium materials should be completed to expand their *** implementing these suggestions,the overall level of China’s titanium industry will be greatly improved,thereby rapidly establishing an advanced scientific and technological country.

关键词： titanium titanium resources prodcution cost high-end titanium material steel-titanium joint prodcution

Vectorial Ekeland variational principle for systems of equilibrium problems and its applications

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Science China Mathematics 2017年第7期60卷 1259-1280页

作者： qiu Jinghui School of Mathematical Sciences Soochow University Suzhou 215006 China

For a family of vector-valued bifunctions,we introduce the notion of sequentially lower monotonity,which is strictly weaker than the lower semi-continuity of the second variables of the ***,we give a general version of vectorial Ekeland variational principle(briefly,denoted by EVP) for a system of equilibrium problems,where the sequentially lower monotone objective bifunction family is defined on products of sequentially lower complete spaces(concerning sequentially lower complete spaces,see Zhu et al(2013)),and taking values in a quasi-ordered locally convex ***,the perturbation consists of a subset of the ordering cone and a family {p_i}_(i∈I) of negative functions satisfying for each i∈I,p_i(x_i,y_i) = 0 if and only if x_i=y_*** the general version,we can deduce several particular equilibrium versions of EVP,which can be applied to show the existence of solutions for countable systems of equilibrium *** particular,we obtain a general existence result of solutions for countable systems of equilibrium problems in the setting of sequentially lower complete *** weakening the compactness of domains and the lower semi-continuity of objective bifunctions,we extend and improve some known existence results of solutions for countable system of equilibrium problems in the setting of complete metric spaces(or Fréchet spaces).When the domains are non-compact,by using the theory of angelic spaces(see Floret(1980)),we generalize some existence results on solutions for countable systems of equilibrium problems by extending the framework from reflexive Banach spaces to the strong duals of weakly compactly generated spaces.

关键词： Ekeland variational principle equilibrium problem system of equilibrium problems quasi-ordered locally convex space angelic space sequentially lower complete space

Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation

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Acta Mechanica Sinica 2018年第2期34卷 266-274页

作者： x.h.Zhang D.S.Luo x.B.Lu L.L.Liu C.L.Liu Institute of Mechanics Chinese Academy of SciencesBeijing 100190China College of Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Gas hydrate Ministry of Land and ResourcesQingdao 266071China Qingdao Institute of Marine Geology Qingdao 266071China

The changes in the mechanical properties of gas hydrate-bearing sediments(GhBS) induced by gas hydrate(Gh) dissociation are essential to the evaluation of Gh exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GhBS at a given Gh saturation under the non-dissociated condition. In this paper, GhBS was formed by the gas saturated method, Gh was dissociated by depressurization until the Gh saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with Gh dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with Gh dissociated saturation were presented.

关键词： Gas hydrate-bearing sediments Dissociation Mechanical properties Shear strength Triaxial test

Empirical models for predicting lateral spreading considering the effect of regional seismicity

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Earthquake Engineering and Engineering Vibration 2012年第1期11卷 121-131页

作者： Zhang Jian Yang Changwei John x. Zhao Graeme h. Mcgerry Department of Civil Engineering Southwest Jiaotong University Chengdu 610031 China GNS Science Lower Hutt New Zealand

A revised empirical model has been developed for predicting liquefaction-induced lateral spreading displacement （LD） as a function of both response spectral acceleration derived from strong-motion attenuation models and geotechnical parameters from Youd＇s LD data set （Youd website）. This revised model is different from the model of Zhang and Zhao, which overcame some drawbacks of earlier models for predicting lateral spreading and was primarily used in Japan and the western U.S. The revised model can potentially be applied anywhere if ground shaking （in terms of 5% damped acceleration or displacement response spectra） can be estimated using local strong-motion attenuation relationships. The revised model is examined using data from Japan and the western U.S. and applied to Turkey and New Zealand, where the ground shaking is estimated using appropriate strong-motion attenuation relationships for each region. The accuracy of the revised model is evaluated by comparing its predicted lateral displacements with those measured in actual earthquakes. The results show that the revised model can account for the effects of local seismicity on lateral spreading displacements and is comparable with existing prediction models.

关键词： lateral spreading liquefaction strong-motion attenuation

Experimental investigation on the wake interference among wind turbines sited in atmospheric boundary layer winds

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Acta Mechanica Sinica 2017年第4期33卷 742-753页

作者： W.Tian A.Ozbay x.D.Wang h.hu School of Aeronautics and Astronautics Shanghai Jiao Tong University Department of Aerospace Engineering Iowa State University School of Energy Power and Mechanical Engineering North China Electric Power University

We examined experimentally the effects of incoming surface wind on the turbine wake and the wake interference among upstream and downstream wind turbines sited in atmospheric boundary layer（ABL） winds. The experiment was conducted in a large-scale ABL wind tunnel with scaled wind turbine models mounted in different incoming surface winds simulating the ABL winds over typical offshore/onshore wind farms. Power outputs and dynamic loadings acting on the turbine models and the wake flow characteristics behind the turbine models were quantified. The results revealed that the incoming surface winds significantly affect the turbine wake characteristics and wake interference between the upstream and downstream turbines. The velocity deficits in the turbine wakes recover faster in the incoming surface winds with relatively high turbulence levels. Variations of the power outputs and dynamic wind loadings acting on the downstream turbines sited in the wakes of upstream turbines are correlated well with the turbine wakes characteristics. At the same downstream locations, the downstream turbines have higher power outputs and experience greater static and fatigue loadings in the inflow with relatively high turbulence level, suggesting a smaller effect of wake interference for the turbines sited in onshore wind farms.

关键词： turbulence winds upstream downstream turbine simulating turbulent averaged faster fatigue

Dynamic Impact of high-Density Aluminum Foam

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Acta Mechanica Solida Sinica 2022年第2期35卷 198-214页

作者： Q.Peng J.xie h.S.Ma x.Ling x.Liu Y.G.Wei LNM Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China School of Engineering and Technology China University of GeosciencesBeijing 100083China College of Engineering Peking UniversityBeijing 100871China

high-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 *** this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,*** on the derived model,we performed finite element simulation to study the impact response of the present *** dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after *** the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.

关键词： high density aluminum Foam Deshpande-Fleck model Finite element method Impact analysis Plastic wave

World Meteorological Organization: scaling the peaks for social benefits

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National Science Review 2018年第6期5卷 947-952页

作者： Jane qiu NSR

Climate change is tightening its grip on high mountains. Yet, unlike their island counterparts, the ordeals facing mountain communities are under-studied and under-appreciated. But that’s about to change. The World M... 详细信息

关键词： scaling the peaks for social benefits World Meteorological Organization Organization

CREVICE CORROSION BEhAVIOR OF x70 STEEL IN hCO_3^- SOLUTION UNDER CAThODIC POLARIZATION

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Acta Metallurgica Sinica(English Letters) 2008年第4期21卷 235-244页

作者： C.W. Du x.G. Li x. Chen P. Liang h. Guo School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Liaoning University of Petroleum and Chemical Technology ~shun 113001 China

The crevice corrosion behavior of xTO steel was investigated with a wedge-shaped crevice assembly under -1000 m V （SCE） cathodic polarization in the solutions with various hCO3 concentrations. The potential, current, ph and the oxygen content within the crevice were measured with or without outside coupled specimen. The results indicated that the polarization potential of xTO steel in the crevice dropped with the increase of time under the cathodic polarization. There was a remarkable influence of hCO3 concentration on the potential of xTO steel in the crevice. When hCO3 concentration was up to 0.125%, the surface of the metal was covered with the corrosion products that resulted in the polarization extent of xTO steel decreased. The ph value in the crevice rose and it dropped gradually from the crevice mouth to the bottom under the cathodic polarization. With the increasing of hCO3 concentration, the hydrolyzation reaction of metal in the crevice bottom aggravated. Most of the dissolved oxygen in the crevice was consumed by the cathodic current. The maximum cathodic current on the metal surface was at the crevice mouth and it was much more than that at the crevice bottom.

关键词： Cathodic polarization xTO steel Potential ph value Oxygen