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Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

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Thermal and hydrological processes in permafrost slope wetlands affect thermosyphon embankment stability

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Advances in Climate Change Research 2024年第4期15卷 680-694页

作者： Bo-Wen TAI Qing-Bai WU Xiao-Ming XU State Key Laboratory of Frozen Soil Engineering Key Laboratory of Cryospheric Science and Frozen Soil EngineeringNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

To ensure the long-term service performance of infrastructure such as railways,highways,airports and oil pipelines built on permafrost slope wetland sites,it is imperative to systematically uncover the long-term heat-water changes of soil in slope wetlands environment under climate *** specifically,considering valuable field data from 2001 to 2019,the long-term heat and water changes in active layers of the slope wetland site along the Qinghai-Xizang Railway(QXR)are illustrated,the effect of thermosyphon measures in protecting the permafrost environment is evaluated,and the influences of climate warming and hydrological effects on the stability of slope wetland embankments are systematically *** permafrost at the slope wetland site is rapidly degrading,demonstrating a reduction in active layer thickness of>3.7 cm per year and a permafrost temperature warming of>0.006℃ per *** thermosiphon embankment developed by QXR has a specific cooling period;thus,to mitigate the long-term impacts of climate warming on the thermal stability of permafrost foundation,it is essential to implement strengthening measures for the thermosiphon embankment,such as adding a crushed-rock layer or sunshade board on the slope of thermosiphon embankment to creating a composite cooling ***-term seasonal groundwater seepage intensifies frost damage to the slope wetland embankment,while long-term seasonal supra-permafrost water and groundwater seepage exacerbates uneven transverse deformation of slope wetland ***-term climate warming and slope effects have altered the surface water and groundwater hydrological processes of slope wetlands,potentially leading to an increased occurrence of slope embankment *** results are crucial for improving our understanding of heat and water variation processes in the active layer of slope wetland sites located in permafrost regions and ensuring long-term service safety for the QXR.

关键词： Heat and water process Active layer Slope wetland Permafrost environment Thermosyphon embankment

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Highly dispersed atomic-level Ni active sites confined in defects for efficient electrocatalytic reduction of carbon dioxide

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Journal of Energy Chemistry 2024年第12期99卷 1-10页

作者： Wenjun Zhang Chen Zhao Yang Yang Ruotong Chen Yue Wu Jiaqi Dai Yuxing Zhang Huajie Liu Mingyang Liu College of Environmental Science and Engineering State Key Laboratory of Medicinal Chemical BiologyNankai UniversityTianjin 300350China School of Chemical Science and Engineering Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education and Shanghai Research Institute for Intelligent Autonomous SystemsTongji UniversityShanghai200092China

Electrocatalytic CO_(2) reduction reaction (eCO_(2)RR) presents a promising approach for harnessing renewable energy and converting greenhouse gas (CO_(2)) into high value-added CO products.N-doped single atom (SA) and atomic-level metal nanocluster (MN) tandem catalysts with rich defects for eCO_(2)RR are reported,which achieved a maximum CO Faraday efficiency (FE_(CO)) of 97.7%(-0.7 V ***) in the H-type cell and maintained over 95% FE_(CO)at potentials from -0.18 to -0.73 V *** in the flow ***,the catalyst in the flow cell demonstrated a remarkably low onset potential of-0.14 V *** and the current density was approximately three times that of the H-type ***,XPS analysis indicates that carbon substrates containing defects have more pyridine-N *** calculations and in-situ attenuated total reflection Fourier transform infrared support this finding by showing that the Ni-(N-C_(2))_(3) active sites with defect favors preferentially convert CO_(2)-to-CO.

关键词： Electrocatalytic CO_(2)RR Atomic-level nanoclusters Defects Catalytic mechanism

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Enhancing Low-Frequency Microwave Absorption Through Structural Polarization Modulation of MXenes

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Nano-Micro Letters 2024年第10期16卷 435-452页

作者： Bo Shan Yang Wang Xinyi Ji Yi Huang College of Light Industry Science and Engineering State Key Laboratory of Biobased Fiber Manufacturing TechnologyTianjin University of Science and TechnologyTianjin 300457People's Republic of China National Institute for Advanced Materials Tianjin Key Laboratory of Metal and Molecule Based Material ChemistryKey Laboratory of Functional Polymer MaterialsCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)School of Materials Science and EngineeringNankai UniversityTianjin 300350People's Republic of China

Two-dimensional carbon-based materials have shown promising electromagnetic wave absorption capabilities in mid-and high-frequency ranges,but face challenges in low-frequency absorption due to limited control over polarization response mecha-nisms and ambiguous resonance *** this study,we pro-pose a novel approach to enhance absorption efficiency in aligned three-dimensional(3D)MXene/CNF(cellulose nanofibers)cavities by modifying polarization properties and manipulating resonance response in the 3D MXene *** controlled polarization mechanism results in a significant shift of the main absorption region from the X-band to the S-band,leading to a remarkable reflection loss value of-47.9 dB in the low-frequency ***,our findings revealed the importance of the oriented electromagnetic coupling in influencing electromagnetic response and microwave absorption *** present study inspired us to develop a generic strategy for low-frequency tuned absorption in the absence of magnetic element participation,while orientation-induced polarization and the derived magnetic resonance coupling are the key controlling factors of the method.

关键词： Hierarchical structure MXene Microwave absorption Low-frequency

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Arch formation mechanism and discharge process of cohesive fine powder in a vibrated silo

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Particuology 2024年第11期94卷 373-385页

作者： Jingzhen Zhu Kun Wang Yu Ma Wentao Xu Jiecai Long Xiwen Li State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment Guangdong University of TechnologyGuangzhou510006China

The arch formation mechanism and discharge process of a very cohesive fine powder(calcium carbonate)in a vibrated silo was investigated by experiments and discrete element method(DEM)*** experimental setup is built to study the flow behaviors with the proposed image-based flow rate measurement method.A cohesive DEM model is used to investigate the dynamic behaviors of the powder *** indicate that the arch formation depends on the vibration acceleration amplitude and is slightly affected by the *** powder discharge flow rate increases with vibration acceleration amplitude and decreases with *** the acceleration amplitude exceeds 15 g,the flow rate tends to *** the acceleration amplitude exceeds 1 g,there is separation and collision between the powder bed and the silo *** collision leads to a significant increase in the contact force.

关键词： Cohesive fine powder Silo discharge Vertical vibration Arch formation Flow rate Discrete element method

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Loosening earth pressure above shallow trapdoor in unsaturated soil with different groundwater level

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Frontiers of Structural and Civil engineering 2024年第10期18卷 1626-1635页

作者： Yun ZHAO Zhongfang YANG Zhanglong CHEN Daosheng LING College of Civil Engineering and Architecture Henan University of TechnologyZhengzhou 450001China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China State Key Laboratory of Hydro-Science and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China

The consideration of unsaturated conditions is infrequently addressed in current Terzaghi’s soil arching research.A modified analytical method for calculation of unsaturated loosening earth pressure above shallow trapdoor is proposed in this *** assuming the existence of a vertical slip surface above the trapdoor,the stress state of the soil in the loosening area are delineated in the extended Mohr–Coulomb *** account for the non-uniform distribution of vertical stress at arbitrary points along the horizontal differential soil trip,a virtual rotation circle trajectory of major principal stress is ***,the average vertical stress acting on the soil trip is determined through integral *** into account the influence of matric suction on soil weight and apparent cohesion,the differential equation governing the soil trip is solved analytically for cases of uniform matric suction distribution and alternatively using the finite difference method for scenarios involving non-uniform matric suction *** proposed method’s validity is confirmed through comparison with published *** parameter analysis indicates that the loosening earth pressure initially decreases and subsequently increases with the increase of the soil *** the rise of groundwater level,the normalized effective loosening earth pressure shows a decreasing trend.

关键词： soil arching effect unsaturated soil trapdoor test loosening earth pressure groundwater level variation

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In-situ construction of nano-multifunctional interlayer to obtain intimate Li/garnet interface for dendrite-free all solid-state battery

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材料科学技术（英文版） 2025年第3期206卷 248-256页

作者： Shiyu Yu Zhinan Gong Min Gao Jie Li Wenfei Xie Yaqing Wei De Li Liang Yang Daming Chen Yuanxun Li Yong Chen State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti ResourcesHainan UniversityHaikou 570228China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054China Guangdong Key Laboratory for Hydrogen Energy Technologies School of Materials Science and Hydrogen EnergyFoshan UniversityFoshan 528000China

Garnet-based all-solid-state lithium batteries(ASSLBs)were considered as the most promising energy storage device due to their high energy density and good ***,interface problems caused by impurities such as Li2CO3 on the surface still hinder the practical application of garnet-based ***,we use a simple ultrasonic spraying method to coat SiO2 on the Li6.4La3Zr1.4Ta0.6O12(LLZTO)surface,and in-situ construct Li4SiO4/Li2O/Li21 Si5 nano-multifunctional interlayer through the high-temperature conversion reaction of *** and density functional theory(DFT)calculations demonstrate that the introduced Li4SiO4/Li20/Li21 Si5 nano-multifunctional interlayer at the LLZTO/Li interface can sig-nificantly improve the air stability and interface contact of LLZTO/*** a result,the interface impedance of Li/SiO2@LLZTO/Li was reduced to 24.2 Ω cm-2,and it can operate stably over 2400 and 1000 h at current densities of 0.05 and 0.2 mA cm-2,*** full cell assembled with LiFePO4(LFP)as cathode(Li/SiO2@LLZTO/LFP)also exhibits excellent cycling performance(capacity retention rate of 95％after 50 cycles at 0.1 C)and rate performance(140 mAh g-1 at 0.1 C and 107 mAh g-1 at 1 C).This re-search provides a strategy to improve interface problems and achieve dendrite-free ASSLBs through in-situ transformation constructed nano-multifunctional interlayers.

关键词： Garnet electrolyte In-situ construction Ultrasonic spraying Nano-multifunctional interlayer All solid-state lithium batteries(ASSLBs)

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Interbasin groundwater flows in the Yarlung Zangbo River Basin and its surrounding areas:A perspective

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science China(Technological sciences) 2025年第4期68卷 299-301页

作者： Jianxin CHEN Xingxing KUANG Linfeng FAN Chunmiao ZHENG Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen518000China State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610000China

Interbasin groundwater flows(IGFs)are movements of groundwater across topographic basin boundaries,which can either contribute to or deplete the water resources of a basin[1].Basins that net-export groundwater beyond their topographic boundaries are termed groundwater exporters,whereas those that receive groundwater from beyond their topographic confines are known as groundwater *** studies have highlighted that the Yarlung Zangbo River Basin(YZRB)is under the impact of IGFs[2,3].

关键词： interbasin groundwater flows interbasin groundwater flows igfs groundwater importers water resources movements groundwater groundwater exporters Yarlung Zangbo River Basin

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Online Queue-Aware Service Migration and Resource Allocation in Mobile Edge computing

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IEEE Transactions on Vehicular Technology 2025年第5期74卷 8063-8078页

作者： Du, An Jia, Jie Chen, Jian Wang, Xingwei Huang, Min Northeastern University School of Computer Science and Engineering The Engineering Research Center of Security Technology of Complex Network System Shenyang110819 China Northeastern University Key Laboratory of Intelligent Computing in Medical Image Ministry of Education Shenyang110819 China Northeastern University College of Information Science and Engineering State Key Laboratory of Synthetical Automation for Process Industries Shenyang110819 China

Mobile edge computing (MEC) integrated with Network Functions Virtualization (NFV) helps run a wide range of services implemented by Virtual Network Functions (VNFs) deployed at MEC networks. This emerging paradigm offers flexible edge resource management for Internet Service Providers (ISPs) and improves service satisfaction of diverse applications. However, a critical challenge lies in processing extremely unpredictable and bursty traffic flow, especially in event-trigger sensing tasks. In this paper, we study queue-aware service migration and resource allocation in an MEC network, where different devices with different arrival patterns request different network services. To this end, we first formulate a novel long-term operation cost minimization problem subject to the stability of multiple queues by adopting a simultaneous migration scheme and determining resource allocation dynamically. To address the problem efficiently, we propose an online control framework to make decisions without any prior system *** first adopt the Lyapunov optimization technique to decompose the long-term optimization problem into multiper-slot subproblems. Then, we adopt a decoupled optimization algorithm based on the coordinate descent method and augmented Lagrangian method to solve the offline mixed integer non-linear programming (MINLP) subproblems. Extensive results reveal that the proposed online optimization framework can efficiently balance queue stability and cost consumption. © 1967-2012 IEEE.

关键词： Mobile edge computing

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A brief review of preparation and applications of monolithic aerogels in atmospheric environmental purification

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Journal of Environmental sciences 2025年第3期149卷 209-220页

作者： Linfeng Nie Shuangde Li Mengjie Cao Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science&Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Monolithic aerogels are promising candidates for use in atmospheric environmental purification due to their structural advantages,such as fine building block size together with high specific surface area,abundant pore structure,***,monolithic aerogels possess a unique monolithic macrostructure that sets them apart from aerogel powders and nanoparticles in practical environmental clean-up *** review delves into the available synthesis strategies and atmospheric environmental applications of monolithic aerogels,covering types of monolithic aerogels including SiO_(2),graphene,metal oxides and their combinations,along with their preparation *** particular,recent developments for VOC adsorption,CO_(2)capture,catalytic oxidation of VOCs and catalytic reduction of CO_(2)are ***,challenges and future opportunities for monolithic aerogels in the atmospheric environmental purification field are *** reviewprovides valuable insights for designing and utilizing monolithic aerogel-based functional materials.

关键词： Monolithic aerogel Environmental purification Catalysis Adsorption

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