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Experimental study on dynamic mechanical property of cemented tailings backfill under SHPB impact loading

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International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 404-416页

作者： Yu-ye Tan Xin Yu Davide Elmo Lin-hui Xu wei-dong song Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education of China) University of Science and Technology Beijing School of Civil and Resources Engineering University of Science and Technology Beijing Norman B.Keevil Institute of Mining Engineering Applied Science SchoolUniversity of British Columbia

Cemented tailings backfill(CTB) have increasingly been used in recent years to improve the stability of mining stopes in deep underground mines. Deep mining processes are often associated with rock bursting and high-speed dynamic loading conditions. Therefore, it is important to investigate the characteristics and dynamic mechanical behavior of CTB. This paper presents the results of dynamic tests on CTB specimens with different cement and solid contents using a split Hopkinson pressure bar(SHPB). The results showed that some CTB specimens exhibited one to two lower stress peaks after reaching dynamic peak stress before they completely failed. The greater the cement-to-tailings ratio is, the more obvious the strain reaction. This property mainly manifested as follows. First,the dynamic peak stress increased with the increase of the cement-to-tailings ratio when the impact velocity was fixed. Second, the dynamic peak stress had a quadratic relationship with the average stress rate. Third, the cement-to-tailings ratio could enhance the increase rate of dynamic peak stress with strain rate. In addition, the dynamic strength enhancement factor K increased with the increase of strain rate, and its value was larger than that of the rock samples. The failure modes of CTB specimens under low-speed impact were tensile failure and X conjugate shear failure, where were nearly the same as those under static uniaxial and triaxial compression. The CTB specimens were crushed and broken under critical strain, a failure mode similar to that of low-strength concrete. The results of the experimental research can improve the understanding of the dynamic mechanical properties of CTB and guide the strength design of deep mining backfills.

关键词： impact loading test cemented tailings backfill dynamic mechanical properties split Hopkinson pressure bar

Mechanical behavior of Ti-6Al-4V lattice-walled tubes under uniaxial compression

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Defence Technology（防务技术） 2022年第7期18卷 1124-1138页

作者： Gen-zhu Feng Jing Wang Xin-yuan Li Li-jun Xiao wei-dong song State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Earthquake Engineering Research Center China Institute of Water Resources and Hydropower ResearchBeijing100048PR China Beijing Research Institute of Automation for Machinery Industry Co. LtdBeijing100120China

The compression behavior of the lattice-walled tubes under variable strain rates are investigated by numerical simulation,and the stress-strain relationship of the structure under quasi-static loading is theoretically *** finite element software LS-DYNA is used to simulate the structure established by the beam element,and the critical impact velocity is obtained when the structure collapses layer by *** to the plastic hinge theory and considering the combined action of the beam's bending moment and axial force in the structure,the stress-strain relationship of the structure under quasi-static loading is derived and compared with the experimental *** numerical simulation results reveal that the structure of the single-layer gradient tube(SGC)does not undergo shear deformation under quasi-static and low-speed *** critical speed of the gradient square tube(GS)is higher than that of a cylindrical *** theoretical model can correctly reflect the mechanical response of the structure under uniaxial compression.

关键词： Lattice-walled tubes Plastic hinge theory Numerical simulation Critical velocity

Fractal and microscopic quantitative characterization of unclassified tailings flocs

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International Journal of Minerals,Metallurgy and Materials 2021年第9期28卷 1429-1439页

作者： Di Zheng wei-dong song Yu-ye Tan Shuai Cao Zi-long Yang Li-juan Sun State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory for Nonlinear Mechanics(LNM) Institute of Mechanics Chinese Academy of ScienceBeijing 100190China

A series of laboratory investigations are conducted to analyze the effect of flocculant type on the spatial morphology and microstructural characteristics of flocs during the flocculation and settling of *** flocculant types(i.e.,ZYZ,JYC-2,ZYD,and JYC-1)are considered in this *** fractal characteristics and internal structures of tailings flocs with different flocculant types and settlement heights are analyzed by conducting scanning electron microscopy and X-ray micro-computed tomography scanning experiments based on the fractal *** show that unclassified tailings flocs are irregular clusters with fractal characteristics,and the flocculation effect of the four flocculant types has the following trend:ZYZ>JYC-2>ZYD>*** size and average grayscale value of tailings flocs decrease with the increase in settlement *** average grayscale values at the top and bottom are 144 and 103,*** settlement height remarkably affects the pore distribution pattern,as reflected in the constructed three-dimensional pore model of tailings *** top part of flocs has relatively good penetration,whereas the bottom part of flocs has mostly dispersed *** number of pores increases exponentially with the increase in settlement *** contrast,the size of pores initially increases and subsequently decreases with the increase in settlement height.

关键词： tailings flocs fractal dimension settlement height grayscale value three-dimensional pore model

Microstructural Features and Mechanical Behaviors of Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) High-Entropy Alloys Fabricated by Selective Laser Melting Technique

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Acta Metallurgica Sinica(English Letters) 2022年第10期35卷 1591-1606页

作者： Yao Yan wei-dong song Ke-Feng Li Kang Zhao Tong-Tong Sun Kai-Kai song Jian-Hong Gong Li-Na Hu Shenzhen Research Institute of Shandong University Shenzhen518057China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Guangdong Institute of Materials and Processing Guangdong Academy of SciencesGuangdong UniversityGuangzhou510650China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai264209China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan250061China

In this work,high strength and ductile Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) high-entropy alloys(HEAs)were fabricated by the selective laser melting(SLM)*** orthogonal experiments,it was verified that a wide SLM processing parameter window can be used to produce crack-free samples for the investigated *** the printed HEA samples exhibit good densification higher than 98.3%.It was found that obvious epitaxial growth leads to the formation of the cylindrical and equiaxed ordered face-centered cubic(FCC)crystals,displaying the characteristics of sub-cylindrical and sub-cellular *** low-angle grain boundaries(LAGBs)prefer appearing around subgrain structures,while the high-angle grain boundaries(HAGBs)tend to form around coarse *** HEA samples with high and low apparent densities were selected to observe their mechanical properties,which exhibit Vickers hardness higher than 263 HV and do not fail during *** increasing densification,the strength gradually *** to the engineering stress–strain curves during compression,the yield strength is higher than 530 MPa,while the strength near 40%engineering strain is larger than 1840 *** deformation,a large density of dislocations becomes popular within subgrain structures together with the pre-existing dislocations from rapid solidification,leading to the formation of planar and cross slip *** coarse cylindrical crystals,some deformation twins are also induced together with the appearance of a distinct copper-type texture during *** a result,the as-printed samples display better mechanical properties than the as-cast *** present studies provide a very good HEA candidate for the SLM process,but more work should be conducted to achieve excellent comprehensive properties.

关键词： High-entropy alloys Selective laser melting Mechanical properties Microstructures

On Complete Totally Real Pseudo-Umbilical Submanifolds in a Complex Projective Space

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Journal of Mathematical Research and Exposition 2011年第5期31卷 946-950页

作者： Min LIU wei dong song College of Mathematics and Computer Science Anhui Normal University Anhui 241000 P. R. China

Let Mn be a totally real pseudo-umbilical submanifold in a complex projective space CPn＋p. In this paper, we study the position of completeness of Mn. By choosing a suitable frame field, we obtain a rigidity theorem ... 详细信息

关键词： complex projective space totally real submanifolds pseudo-umbilical submanifolds complete.

Hot deformation behavior and constitutive model of TC18 alloy during compression

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Rare Metals 2014年第4期33卷 383-389页

作者： Bao-Hua Jia wei-dong song Hui-Ping Tang Zhi-Hua Wang Xiao-Nan Mao Jian-Guo Ning State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology State Key Laboratory of Porous Metal Materials Northwest Institute for Nonferrous Metal Research Institute of Applied Mechanics and Biomedical Engineering Taiyuan University of Technology Northwest Institute for Nonferrous Metal Research

The hot deformation behavior of TC18 alloy at strain rates ranging from 1 × 10-4 to 1 x 10-2 s-1 and temperatures ranging from 25 to 800 ℃ was studied using a WDW-300 electronic universal testing machine. The relationships between true flow stress decreases with stress and true strain show that the increase of temperature and increases as strain rate increases. The effect of strain rate on the flow stress becomes pronounced at higher temper- atures. At room temperature, the river pattern characteristic of brittle fracture and the dimple pattern typical of ductile fracture are found to exist in different regions of fracture surfaces of the samples. An improved constitutive rela- tionship is proposed to accurately describe the flow stress of TC18 by considering the effect of strain. And a micro- scopic model is also deduced which can link the physical mechanisms to the macroscopic experimental results. A good agreement is obtained between the predictions of the microscopic model and the results of the macroscopic experiment.

关键词： TC18 titanium alloy Hot deformation Strainrate Constitutive model

Enhanced mechanical performance of gradient-structured CoCrFeMnNi high-entropy alloys induced by industrial shot-blasting

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Rare Metals 2023年第3期42卷 982-993页

作者： Ming-Zhi Zhang Kun Zhang Kai-Kai song Xiao-Yu Zou wei-dong song Ke-Feng Li Li-Na Hu Ze-Qun Zhang Jürgen Eckert Shenzhen Research Institute of Shandong University Shenzhen 518057China CAS Key Laboratory of Microgravity(National Microgravity Laboratory) Institute of MechanicsChinese Academy of SciencesBeijing100190China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai 264209China Guangdong Institute of Materials and Processing Guangdong Academy of SciencesGuangzhou 510650China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China Erich Schmid Institute of Materials Science Austrian Academy of SciencesLeoben 8700Austria Department of Materials Science Montanuniversitat LeobenLeoben 8700Austria

In this study,CoCrFeMnNi high-entropy alloys(HEAs)with a surface gradient nanostructure were produced using industrial shot blasting,which improved their mechanical properties compared to the untreated *** severely plastically deformed(SPD)surface layer had a multi-scale hierarchical structure with a high density of stacking faults,deformation nanotwins,and amorphous *** depth of the SPD layer steadily increased as the shot-blasting time *** differences in the microhardness and tensile strength before and after shotblasting demonstrated the significant effect of the SPD layer on the mechanical *** microhardness of the homogenized HEA was~5 *** comparison,the maximum microhardness of the specimens after 20 min of shot blasting was~8.0 GPa at the *** yield strength also improved by 178%,and a large ductility of~36%was *** nanograin boundary,stacking fault,and twin strengthening within the gradientnanostructured surface layer caused the strength to *** tensile deformation,strain concentration began at the surface of the specimen and gradually spread to the ***,the gradient-nanostructured surface layer with improved strain hardening can prevent early necking and ensure steady plastic deformation so that high toughness is achieved.

关键词： High-entropy alloy Shot blasting Gradient structure Mechanical property Deformation mechanism

Proteomic analysis and miRNA profiling of human testicular endothelial cell-derived exosomes:the potential effects on spermatogenesis

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Asian Journal of Andrology 2022年第5期24卷 478-486页

作者： Wen-Peng song Sheng-Ji Gu Xiao-Hui Tan Yang-Yang Gu wei-dong song Jian-Yu Zeng Zhong-Cheng Xin Rui-Li Guan Department of Urology Peking University First HospitalBeijing 100034China Institute of Urology Peking UniversityBeijing 100034China Beijing Key Laboratory of Urogenital Diseases(Male)Molecular Diagnosis and Treatment Center Beijing 100034China Department of Dental Implant Center Beijing Stomatological HospitalSchool of StomatologyCapital Medical UniversityBeijing 100050China Department of Radiation Medicine Institute of Systems BiomedicineSchool of Basic Medical SciencesPeking University Health Science CenterBeijing 100191China

Testicular endothelial cells have been found to play an important role in spermatogenesis and fertility,but their mechanism is *** released by various cells are recognized as cell–cell communication mediators during the initiation and progression of many ***,the current study aimed to investigate the protein and miRNA components of human testicular endothelial cell-derived exosomes(HTEC-Exos)and to explore their potential effects on *** this study,HTEC-Exos were first isolated by the ultracentrifugation method,and then identified by nanoparticle tracking analysis,transmission electron microscopy(TEM),and western *** characteristics of HTEC-Exos were examined by liquid chromatography–mass spectrometry and microRNA(miRNA)chip *** analysis was performed to explore the potential role of the exosomal content on spermatogenesis.A total of 945 proteins were identified,11 of which were closely related to spermatogenesis.A total of 2578 miRNAs were *** them,30 miRNAs demonstrated potential associations with male reproductive disorders,such as azoospermia,and spermatogenesis *** particular,11 out of these 30 miRNAs have been proven to be involved in spermatogenesis based on available *** study provides a global view of the proteins and miRNAs from HTEC-Exos,suggesting that HTEC-Exos may function as potential effectors during the process of spermatogenesis.

关键词： exosomes microRNAs proteomics testicular endothelial cells

The 14th Asia-Pacific Society for Sexual Medicine （APSSM2013）

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Asian Journal of Andrology 2013年第6期15卷 855-856页

作者： Yong De Xu Hong En Lei wei dong song Andrology Center Peking University first Hospital Beijing 100034 China

The Asia-Pacific Society for Sexual Medicine （APSSM） was established in 1987 in Hong Kong as a regional affiliated society of International Society for Sexual Medicine （ISSM）, and its biennial meeting is held in different Asia-Pacific countries or regions biennially. The 14th PSSM was successfully held in Kanazawa, Japan on May 31-June 2, 2013. Professor Mikio Namiki chaired this meeting. Attracted to the comprehensively well-designed scientific programm, nearly 500 delegates across the filed of urological surgery, andrology, reproductive medicine, endocrinology, spiritual psychology and geriatric medicine from all of the world came together and discussed the important and hot topics across the filed. Over 200 abstracts were presented. The active discussion and reaction in the meeting had to complete due to the limited time, but the resounding outcome and the lasting reflection will be kept for a long time in minds of all attendees. Here we summarize APSSM2013 as below.

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