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Homovalent doping: An efficient strategy of the enhanced TiNb2O7 anode for lithium-ion batteries

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Green Energy & environment 2024年第8期9卷 1257-1266页

作者： Xiaohe Jin Yirui Deng Han Tian Miaomiao Zhou Wenhao Tang Huiyou Dong Xinquan Zhang Ruiping Liu department of Materials Science and engineering China University of Mining & Technology (Beijing) department of Materials Science and engineering China University of Mining&Technology (Beijing)

The low energy density,unsatisfied cycling performance,potential safety issue and slow charging kinetics of the commercial lithium-ion batteries restrained their further application in the fields of fast charging and long-haul electric *** TiNb2O7（TNO） with the theoretical capacity of 387 mAh g-1has been proposed as a high-capacity anode materials to replace *** this work,homovalent doping strategy was used to enhance the electrochemical performance of Ti Nb2O7（TNO） by employing Zr to partial substitute Ti through solvothermal *** doping of Zr4+ions can enlarge the lattice structure without changing the chemical valence of the original elements,refine and homogenize the grains,improve the electrical conductivity,and accelerate the ion diffusion kinetics,and finally enhance the cycle and rate ***,Z0.05-TNO shows initial discharge capacity of as high as 312.2 mAh g-1at 1 C and 244.8 mAh g-1at 10 C,and still maintains a high specific capacity of 171.3 mAh g-1after 800 cycles at 10 *** study provides a new strategy for high-performance fastcharging energy storage electrodes.

关键词： Homovalent doping Zr 4+ TiNb 2 O 7 Microsphere Lithium-ion batteries

Effects of oxygen vacancy on bond ionicity,lattice energy,and microwave dielectric properties of CeO_(2) ceramics with Yb^(3+) substitution

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Journal of Advanced Ceramics 2024年第2期13卷 247-254页

作者： Mingan Shi Shuyang Ma Wangsuo Xia Ying Wang Jinzi Yu Haitao Wu School of Materials Science and Physics China University of Mining and TechnologyXuzhou 221008China School of environment and Material engineering Yantai UniversityYantai 264005China

Novel Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.8)ceramics,designed by replacing Ce^(4+)with Yb^(3+)ions were prepared by conventional oxide reaction,and the structural stability of the cubic fluorite structure was assessed using lattice energy and ionic properties of Ce/Yb-O *** oxygen vacancy caused by unequal substitution,which played a decisive role in bond ionicity and lattice energy,was analyzed experimentally by XPS and also theoretically by first *** Yb_(x)Ce_(1-x)O_(2-0.5x) ceramics maintain a stable cubic fluorite structure when x≤0.47,corresponding to the minimum lattice energy of 4142 kJ/mol with the lowest ionicity as ƒ_(i)=87.57%.For microwave dielectric properties,when the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0-0.4)ceramics are pure phase,the porosity-corrected permittivity is dependent on the bond *** Q×ƒ values are related to the lattice energy and grain *** temperature coefficient of resonance frequency has been analyzed using bond *** the Yb_(x)Ce_(1-x)O_(2-0.5x)(x=0.5-0.8)ceramics are multiple phases,the microwave dielectric properties are associated with the phase composition and grain growth.

关键词： structure stability bond ionicity oxygen vacancy electronic localization function(ELF)

High-resolution photogrammetry to measure physical aperture of two separated rock fracture surfaces

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 2922-2934页

作者： Masoud Torkan Mateusz Janiszewski Lauri Uotinen Alireza Baghbanan Mikael Rinne department of Civil engineering Aalto UniversityEspooFinland department of mining engineering Isfahan University of TechnologyIsfahanIran

Photogrammetry,reconstructing three-dimensional(3D)models from overlapping two-dimensional(2D)photos,finds application in rock mechanics and rock engineering to extract geometrical details of reconstructed objects,for example rock *** properties are important for determining the mechanical stability,permeability,strength,and shear behavior of the rock *** can be used to reconstruct detailed 3D models of two separated rock fracture surfaces to characterize fracture roughness and physical aperture,which controls the fluid flow,hydromechanical and shear behavior of the rock *** research aimed to determine the optimal number of scale bars required to produce high-precision 3D models of a fracture surface.A workflow has been developed to define the physical aperture of a fracture using *** blocks of Kuru granite(25 cm×25 cm×10 cm)with an artificially induced fracture,were *** scaling 3D models,321 markers were used as ground control points(GCPs)with predefined distances on each *** the samples were wellmatched in their original positions,the entire block was *** data of the GCPs were extracted from the 3D model of the *** half was surveyed separately and georeferenced by GCPs and merged into the same coordinate *** fracture surfaces were extracted from the 3D models and the vertical distance between the two surfaces was digitally calculated as physical *** assessment of the photogrammetric reconstruction showed a 20-30 mm digital control distance accuracy when compared to known distances defined between *** attain this accuracy,the study found that at least 200 scale bars were ***,photogrammetry was employed to measure changes in aperture under normal *** results obtained from this approach were found to be in good agreement with those obtained using linear variable displacement transducers(LVDTs),with differences ran

关键词： Photogrammetry Physical aperture Rock fracture Predefined distances Markers

Advancing respirable coal mine dust source apportionment:a preliminary laboratory exploration of optical microscopy as a novel monitoring tool

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International Journal of Coal Science & Technology 2024年第2期11卷 222-233页

作者： Nestor Santa Emily Sarver department of mining and Minerals engineering Virginia TechBlacksburgVA 24061USA

Exposure to respirable coal mine dust(RCMD)can cause chronic and debilitating lung ***-time monitoring capabilities are sought which can enable a better understanding of dust components and *** many underground mines,RCMD includes three primary components which can be loosely associated with three major dust sources:coal dust from the coal seam itself,silicates from the surrounding rock strata,and carbonates from the inert‘rock dust’products that are applied to mitigate explosion hazards.A monitor which can reliably partition RCMD between these three components could thus allow source *** tracking silicates,specifically,could be valuable since the most serious health risks are typically associated with this component-particularly if abundant in crystalline *** a monitoring concept based on field microscopy,and following up on prior research using polarized light,the aim of the current study was to build and test a model to classify respirable-sized particles as either coal,silicates,or *** model development,composite dust samples were generated in the laboratory by successively depositing dust from high-purity materials onto a sticky transparent substrate,and imaging after each deposition event such that the identity of each particle was known a *** testing followed a similar approach,except that real geologic materials were used as the source for each dust *** showed that the model had an overall accuracy of 86.5%,indicating that a field-microscopy based moni-tor could support RCMD source apportionment and silicates tracking in some coal mines.

关键词： Polarized light microscopy Image processing Dust monitoring Respirable silica Coal mining

Predicting uniaxial compressive strength of tuff after accelerated freeze-thaw testing: Comparative analysis of regression models and artificial neural networks

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Journal of Mountain Science 2024年第10期21卷 3521-3535页

作者： Ogün Ozan VAROL department of mining engineering Faculty of EngineeringVan Yuzuncu Yil UniversityVan 65080Türkiye

Ignimbrites have been widely used as building materials in many historical and touristic structures in the Kayseri region of Türkiye. Their diverse colours and textures make them a popular choice for modern construction as well. However, ignimbrites are particularly vulnerable to atmospheric conditions, such as freeze-thaw cycles, due to their high porosity, which is a result of their formation process. When water enters the pores of the ignimbrites, it can freeze during cold weather. As the water freezes and expands, it generates internal stress within the stone, causing micro-cracks to develop. Over time, repeated freeze-thaw (F-T) cycles lead to the growth of these micro-cracks into larger cracks, compromising the structural integrity of the ignimbrites and eventually making them unsuitable for use as building materials. The determination of the long-term F-T performance of ignimbrites can be established after long F-T experimental processes. Determining the long-term F-T performance of ignimbrites typically requires extensive experimental testing over prolonged freeze-thaw cycles. To streamline this process, developing accurate predictive equations becomes crucial. In this study, such equations were formulated using classical regression analyses and artificial neural networks (ANN) based on data obtained from these experiments, allowing for the prediction of the F-T performance of ignimbrites and other similar building stones without the need for lengthy testing. In this study, uniaxial compressive strength, ultrasonic propagation velocity, apparent porosity and mass loss of ignimbrites after long-term F-T were determined. Following the F-T cycles, the disintegration rate was evaluated using decay function approaches, while uniaxial compressive strength (UCS) values were predicted with minimal input parameters through both regression and ANN analyses. The ANN and regression models created for this purpose were first started with a single input value and then dev

关键词： Ignimbrite Uniaxial compressive strength Freeze-thaw Decay function Regression Artificial neural network

Experimental study of face passive failure features of a shallow shield tunnel in coastal backfill sand

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Frontiers of Structural and Civil engineering 2024年第2期18卷 252-271页

作者： Weifeng QIAN Ming HUANG Bingnan WANG Chaoshui XU Yanfeng HU School of Civil engineering Fuzhou UniversityFuzhou 350108China School of Civil Environment and Mining EngineeringUniversity of AdelaideAdelaide 5005Australia China First Highway Xiamen engineering Co. Ltd.Xiamen 361000China

Face passive failure can severely damage existing structures and underground utilities during shallow shield tunneling,especially in coastal backfill *** this work,a series of laboratory model tests were developed and conducted to investigate such failure,for tunnels located at burial depth ratios for which C/D=0.5,0.8,1,and *** pressures,the evolution of failure processes,the failure modes,and the distribution of velocity fields were examined through model tests and numerical *** support pressure in the tests first rose rapidly to the elastic limit and then gradually increased to the maximum value in all *** maximum support pressure decreased slightly in cases where C/D=0.8,1,and 1.3,but the rebound was insignificant where C/D=*** addition,the configuration of the failure mode with C/D=0.5 showed a wedge-shaped arch,which was determined by the outcropping shear *** configuration of failure modes was composed of an arch and the inverted trapezoid when C/D=0.8,1,and 1.3,in which the mode was divided into lower and upper failure zones.

关键词： tunnel face stability passive failure model test support pressure failure mode

Recycling arsenic-containing bio-leaching residue after thermal treatment in cemented paste backfill:Structure modification,binder properties and environmental assessment

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2136-2147页

作者： Dengfeng Zhao Shiyu Zhang Yingliang Zhao department of mining engineering Lyuliang UniversityLvliang 033000China School of Civil and environmental engineering University of Science and Technology BeijingBeijing 100083China School of mining engineering Taiyuan University of TechnologyTaiyuan 030024China department of Civil and environmental engineering The Hong Kong Polytechnic UniversityHong Kong 00852China

The substantial arsenic(As)content present in arsenic-containing bio-leaching residue(ABR)presents noteworthy environ-mental challenges attributable to its inherent instability and susceptibility to *** its elevated calcium sulfate content,ABR exhibits considerable promise for industrial *** study delved into the feasibility of utilizing ABR as a source of sulfates for producing super sulfated cement(SSC),offering an innovative binder for cemented paste backfill(CPB).Thermal treatment at varying temperatures of 150,350,600,and 800℃ was employed to modify ABR’s *** investigation encompassed the examination of phase transformations and alterations in the chemical composition of As within ***,the hydration characteristics of SSC utilizing ABR,with or without thermal treatment,were studied,encompassing reaction kinetics,setting time,strength development,and *** findings revealed that thermal treatment changed the calcium sulfate structure in ABR,consequently impacting the resultant sample ***,calcination at 600℃ demonstrated optimal modification effects on both early and long-term strength *** enhanced performance can be attributed to the augmented formation of reaction products and a densified ***,the thermal treatment elicited modifications in the chemical As fractions within ABR,with limited impact on the As immobilization capacity of the prepared binders.

关键词： cemented paste backfill bio-leaching residue arsenic immobilization binder hydration calcination

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Microseismic source location using deep learning:A coal mine case study in China

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Journal of Rock Mechanics and Geotechnical engineering 2024年第9期16卷 3407-3418页

作者： Yue Song Enyuan Wang Hengze Yang Chengfei Liu Baolin Li Dong Chen School of Safety engineering China University of Mining and TechnologyXuzhou221116China State Key Laboratory of Coal Mine Disaster Prevention and Control China University of Mining and TechnologyXuzhou221116China School of environment and Safety engineering North University of ChinaTaiyuan030051China State Key Laboratory for Geomechanics&Deep Underground engineering China University of Mining TechnologyXuzhou221116China

Microseismic source location is crucial for the early warning of rockburst ***,the conventional methods face challenges in terms of the microseismic wave velocity and arrival time *** techniques,such as the full convolutional neural network(FCNN),can capture spatial information but struggle with complex microseismic *** the FCNN with the long shortterm memory(LSTM)network enables better time-series signal classification by integrating multiscale information and is therefore suitable for waveform *** LSTM-FCNN model does not require extensive data preprocessing and it simplifies the microseismic source location through feature *** this study,we utilized the LSTM-FCNN as a regression learning model to locate the seismic ***,the method of short-time-average/long-time-average(STA/LTA)arrival time picking was employed to augment spatiotemporal ***,oversampling the on-site data was performed to address the issue of data imbalance,and finally,the performance of LSTM-FCNN was ***,we compared the LSTM-FCNN model with previous deep-learning *** results demonstrated remarkable location capabilities with a mean absolute error(MAE)of only 7.16 *** model can realize swift training and high accuracy,thereby significantly improving risk warning of rockbursts.

关键词： Microseismic source location Rockburst Deep learning Intelligent early warning

Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading

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Earthquake engineering and engineering Vibration 2024年第4期23卷 845-862页

作者： Van Vi Pham Ngoc Anh Do Piotr Osinski Ngoc Thai Do Daniel Dias Sustainable Development in Underground engineering Research Team Hanoi University of Mining and GeologyHanoiVietnam department of Underground and mining Construction Faculty of Civil EngineeringHanoi University of Mining and GeologyHanoiVietnam department of Geotechnical engineering Institute of Civil EngineeringWarsaw University of Life Sciences-SGGWWarszawaPoland Laboratory 3SR Grenoble Alpes UniversityGrenoble 38400France

The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil *** individual behavior of circular,rectangular,and sub-rectangular tunnels subjected to seismic loadings has already been studied in the *** the present research,two case scenarios of circular,rectangular tunnels and four sub-rectangular shaped tunnels,with similar cross-section areas,were adopted to perform a comprehensive numerical *** purpose of the study was to determine the mechanical behavior of tunnels of different shapes,depending upon seismic *** were performed by considering the influence of soil-lining interaction,soil parameters,and lining thickness,as well as lining *** were performed for no-slip and full-slip *** results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding *** concerns no-slip as well as full-slip soil-lining interaction,especially when the lining is subjected to seismic ***,it is shown that changes in incremental bending moments for circular,rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly.

关键词： tunnel shape soil-lining interaction seismic loading internal forces numerical analysis

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