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Mechanical behaviors of backfill-rock composites: Physical shear test and back-analysis

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 807-827页

作者： Jie Xin Quan Jiang Fengqiang Gong lang liu Chang liu Qiang liu Yao Yang Pengfei Chen State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China School of Civil Engineering Southeast UniversityNanjing211189China Energy School Xi’an University of Science and TechnologyXi’an710054China

The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled rock.To investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission monitoring.In parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing process.Based on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical behavior.The results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,i.***.the first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste backfill.Moreover,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,i.***.the shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing friction.The numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock composites.Based on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal phenomenon.Finally,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical results.The research can advance the better understanding of the shear behavior of backfill-rock composites and contribute to the

关键词： Physical simulation Backfill-rock composites Shear failure Cracking Shear constitutive model

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Cobalt-doped TiO_(2)@C hierarchical nanocomposites derived from Ti_(3)C_(2) MXene as cathodes for hybrid magnesium-lithium batteries

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Nano Research 2024年第1期17卷 253-261页

作者： Xiaohui Li Yakun Tang lang liu Yue Zhang Yang Gao Mao Qian Wenjie Ma State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830017China

TiO_(2)has been explored in hybrid magnesium-lithium batteries(HMLBs)due to the advantages of low self-discharge and small volume expansion during ion insertion.However,how to improve the inherently low ionic and electrical conductivity of TiO_(2)is the problem that needs to be solved.In this work,a smart strategy is adopted to prepare cobalt-doped TiO_(2)@C(Co^(4+)-TiO_(2)@C)hierarchical nanocomposite derived from Co(II)(OH)n@Ti3C2.Compared with TiO_(2)@C(without cobalt doping),Co^(4+)-TiO_(2)@C shows the highest specific capacity(154.7 mAh·g^(-1)at 0.1 A·g^(-1)after 200 cycles)and extraordinary rate performance in HMLBs.The excellent electrochemical performance of Co4+-TiO_(2)@C is ascribed to the synergistic effect of the hierarchical structure and cobalt-doping.Both experimental results and density functional theory(DFT)calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li+migration barrier.This work provides a new insight to design TiO_(2)-based cathode materials with high-performance in HMLBs.

关键词： Ti_(3)C_(2)MXene TiO_(2) hybrid magnesium-lithium batteries hierarchical structure cobalt-doping

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Magnetic, dielectric and luminescence synergetic switchable effects in molecular material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)]

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Chinese Chemical Letters 2024年第4期35卷 502-505页

作者： Yan Cheng Hua-Peng Ruan Yan Peng Longhe Li Zhenqiang Xie lang liu Shiyong Zhang Hengyun Ye Zhao-Bo Hu Chaotic Matter Science Research Center Faculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000China College of Materials and Chemical Engineering Pingxiang UniversityPingxiang 337055China Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Key Laboratory of Jiangxi University for Functional Materials Chemistry School of Chemistry and Chemical EngineeringGannan Normal UniversityGanzhou 341000China

The application of multifunctional materials in various fields such as electronics and signal processors has attracted massive attention. Herein, a new organic-inorganic hybrid material [Et_(3)NCH_(2)Cl]_(2)[MnBr_(4)](1) is reported, which contains two organic amines cations and one [MnBr_(4)] tetrahedral ion. Compound 1 has a dielectric anomaly signal at 338 K, which proves its thermodynamic phase transition. The single crystal measurements at 200 K and 380 K show that the phase transition of compound 1 is caused by the thermal vibration of organic amine cations in the lattice. Moreover, compound 1 shows yellow-green luminescence under UV light irradiation. The magnetism measurements indicate that compound 1 shows switchable magnetic properties. This organic–inorganic material is a multifunctional material with dielectric, optical, and magnetic synergetic switchable effects, which expands a new direction for designing multifunctional materials.

关键词： Synergetic switchable effects Molecular materials Magnetism Dielectric Luminescence

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Heat Storage/Heat Release of Phase-Change Filling Body with Casing Heat Exchanger for Extracting Geothermal Energy

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Journal of Thermal Science 2023年第3期32卷 1171-1189页

作者： ZHANG Xiaoyan XU Muyan liu lang YANG Qixing KI-IL Song Energy School Xi'an University of Science and TechnologyXi'an 710054China Key Laboratory of Western Mines and Hazards Prevention Ministry of Education of ChinaXi'an 710054China Department of Civil Engineering Inha UniversityIncheon 402-751South Korea

Arranging heat exchanger in filling body to extract geothermal energy is an effective way to alleviate the problems of high ground pressure and high ground temperature in deep resource exploitation.Filling body with casing heat exchanger was acted as research object,encapsulating phase change materials(PCMs)in annular space.During heat storage and heat release process,the effects of different PCMs on temperature distribution,phase-change process and heat transfer performance were studied.The result indicates:During heat storage process,the temperature increases rapidly and the melting process is accelerated for the position closer surrounding rock.CaCl_(2)·6H_(2)O/EG can make filling body complete heat storage process in the shortest time because of its good thermal diffusivity.The heat storage capacity of PCMs backfill is significantly higher than that of ordinary backfill;it increases by 36.6%-67.3%at heat storage of 10 h.During heat release process,the closer to the heat exchange tube,the greater the temperature drop in filling body.The maximum value of heat release rate and heat release capacity is in CaCl_(2)·6H_(2)O/EG backfill,it can release 116.4%more heat than RT35backfill after heat release of 12 h,the maximum value of effectiveness and its heat transfer rate also is in CaCl_(2)·6H_(2)O/EG backfill.This paper provides the basic data for the selection of PCMs in phase-change thermal storage filling body.

关键词： flling body heat exchanger phase change material heat storage/heat release

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Enhanced Phase Change Heat Storage of Layered Backfill Body under Different Boundary Conditions

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Journal of Thermal Science 2023年第3期32卷 1190-1212页

作者： ZHANG Xiaoyan ZHAO Min liu lang ZHAO Yujiao HUAN Chao ZHANG Bo Energy School Xi'an University of Science and TechnologyXi'an 710054China Key Laboratory of Western Mines and Hazards Prevention Ministry of Education of ChinaXi'an 710054China

In view of the high temperature problem faced by mining activities,the coordinated mining of ore deposit and geothermal energy is a solution in line with the concept of green mining.The layered backfill body with finned double-pipe heat exchanger continuously exchanges heat with the surrounding thermal environment,which plays an effective role in gathering geothermal energy.In this paper,the heat storage process of each layered backfill body under different boundary conditions is simulated by Fluent.The results show the heat storage characteristic of layered backfill body can be significantly improved by adding fins to the double-pipe heat exchanger.On the whole,the heat storage effect of bottom layer backfill body(BLBB)is the best.The total heat storage capacity of top layer backfill body(TLBB),middle layer backfill body(MLBB)and BLBB with the finned double-pipe heat exchanger is 666.3 kJ,662.2 kJ,1003.0 kJ;1639.0 kJ,1760.8 kJ,1911.2 kJ and 1731.1 kJ,1953.3 kJ,1962.8 kJ respectively at 1 h,8 h and 24 h.This study explores the law of heat storage of layered backfill body under different boundary conditions and also expands the idea for layered backfill body to efficiently accumulate geothermal energy.

关键词： layered backfill body boundary conditions phase change heat storage finned double-pipe exchanger geothermal energy of mine

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碳纳米管吸附CHF_(3)的分子模拟研究

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工程热物理学报 2024年第6期45卷 1679-1689页

作者：刘浏刘朝刘浪李期斌重庆大学能源与动力工程学院低品位能源利用技术及系统教育部重点实验室重庆400044

有机朗肯循环中工质可能发生热分解,分解产物对循环性能产生较大影响。本文提出采用多孔材料对热解气体产物进行吸附的方法,以减小工质热解对系统性能的负面影响。采用巨正则蒙特卡洛模拟研究了工质HFO-1234yf主要分解产物CHF_(3)气体... 详细信息

有机朗肯循环中工质可能发生热分解,分解产物对循环性能产生较大影响。本文提出采用多孔材料对热解气体产物进行吸附的方法,以减小工质热解对系统性能的负面影响。采用巨正则蒙特卡洛模拟研究了工质HFO-1234yf主要分解产物CHF_(3)气体在碳纳米管(CNT)中的吸附特性,探究了CNT直径、温度及电荷对吸附的影响。结果表明,(6,6)CNT有着较高CHF_(3)饱和吸附量(2.06 mol·kg^(-1))以及极高的选择系数,但直径较大的CNT更偏向吸附工质HFO-1234yf;温度的升高导致(6,6)CNT对CHF_(3)的吸附量以及选择系数下降;同时带0.05e正电荷的CNT对CHF_(3)吸附量增加近50%,选择系数也有极大提升。

关键词：有机朗肯循环工质热解吸附碳纳米管

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Preparation and Performance of Chitosan/Citric Acid Modified Magnesium Oxychloride Cement

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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1326-1334页

作者： SONG Zijian liu lang YU Peipei ZHANG Yunsheng LI Xincheng CHU Hongqiang JIANG Linhua College of Mechanics and Materials Hohai UniversityNanjing 2100China School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Yunnan Institute of Building Research Co. LtdKunming 650223China

Citric acid(CA)and chitosan(CS)were employed to modify magnesium oxychloride cement(MOC).Multiscale measurements were implemented to study the properties of the modified MOC pastes.Results show that the addition of CA/CS significantly changes the content of each phase and the microstructure of phase 5.The single addition of CA can effectively increase the compressive strength of MOC after 7 d curing,while CS exerts no obvious effect on the compressive strength.As to the simultaneous addition of CA and CS,the compressive strength of MOC gradually decreases with the increasing content of CS.Interestingly,mixing CA and CS significantly enhances the water resistance of MOC and decreases the degradation rate of MOC in phosphate buffered solution,which can be ascribed to the low specific surface area of the plate-like crystals in the modified MOC and the reduction of pores in the structure.

关键词： magnesium oxychloride cement modifier citric acid chitosan

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科研管理视域下的高校交叉学科创新研究

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科技管理研究 2024年第9期44卷 100-107页

作者：张卓刘浪暨南大学广东广州510632

通过讨论交叉学科发展必要性以及存在的困境,发现交叉学科创新虽然取得了一定的成效,但仍然面临着学科交叉的理念意识不足、管理体制和运行机制不完善、多学科背景人才缺乏等问题,并结合个案进行分析,提出组建高起点高标准交叉研究平台... 详细信息

通过讨论交叉学科发展必要性以及存在的困境,发现交叉学科创新虽然取得了一定的成效,但仍然面临着学科交叉的理念意识不足、管理体制和运行机制不完善、多学科背景人才缺乏等问题,并结合个案进行分析,提出组建高起点高标准交叉研究平台、构建交叉人才队伍体系、探索制度创新以及强化组织领导、优化资源配置等建设发展路径,为交叉学科融合创新发展提供模式和对策,不断推动学科发展增长点以及科研竞争力的提升。

关键词：交叉学科科研创新高等院校 “四新”

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Nuclear magnetic moments for J~π=2_1^+ state of ^(10)Be with ab initio Monte Carlo shell model calculation

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 239-243页

作者： liu lang LI Jian School of Science Jiangnan University College of Physics Jilin University

The magnetic moment of 2+1 state for 10Be are calculated and investigated in terms of single particle orbits for protons and neutrons under the framework of ab initio Monte Carlo shell model method in an emax = 3 model space. The reduced matrix elements of orbital and spin angular momentum are evaluated. It is found that the orientations of orbital angular momentum in diferent single particle orbits are consistent. Conversely,the orientations of spin in diferent single particle orbits tend to be chaotic. The nuclear magnetic moment of 2+1 state for 10Be is obtained as 1.006N and is discussed in regards to the contribution of orbital and spin angular momentum both for protons and neutrons. The corresponding g-factor is also given.

关键词：核磁矩壳模型状态蒙地卡罗计算自旋角动量粒子轨道轨道角动量

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Nuclear current and antimagnetic rotation in ^(105)Cd

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Science China(Physics,Mechanics & Astronomy) 2012年第12期55卷 2420-2424页

作者： liu lang ZHAO PengWei State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

The effects of the nuclear current in the antimagnetic rotation band of 105Cd have been investigated in a fully self-consistent and microscopic way by using the tilted axis cranking relativistic mean-field model.It was found that the inclusion of nuclear current leads to a higher angular momentum and thus a larger kinetic moment of inertia at a given rotational frequency.As a consequence,the B(E2) values with current are always smaller than those without current.

关键词：旋转带防磁相对论平均场模型电流引线 CD 完全自洽惯性力矩旋转频率

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