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Analytical study of subcritical crack growth under mode I loading to estimate the roof durability in underground excavation

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International Journal of Mining Science and Technology 2022年第2期32卷 375-385页

作者： Songtao Ji Zeng Wang Jurij Karlovšek Geotechnical Engineering Centre School of Civil EngineeringThe University of QueenslandBrisbane 4067Australia china Coal Technology&Engineering Group Nanjing design&research institute Co. Ltd.Nanjing 210031China

The long-term stability of the roof is particularly important in designing underground rock *** estimate the durability of roof strata in underground excavation,a computation scheme of subcritical crack growth is proposed in this *** adopting the proposed method,the potential collapse location of strata is derivable in accordance with a static model,the durability of roof strata can be estimated,a dynamic time step control strategy is achieved to balance the accuracy and speed of computing,and the initial crack size of rock can be *** addition to the above,a mechanical model of underground excavation with non-uniformly distributed loads and partially yielded foundation is presented as the prototypical case.A set of case studies is carried out that showcase a power correlation between applied stress and roof *** allowable applied tensile stress for a 100-year life cycle is about 76%of the tensile *** using the proposed subcritical crack growth computation scheme,the roof stability in an underground excavation can be identified not only from the spatial view but also from the temporal perspective.

关键词： Roof durability Analytical model Subcritical crack growth Stress intensity factor Initial crack size Dynamic time step

research on the basic theoretical issues of smart metro construction

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Science china(Technological Sciences) 2019年第11期62卷 2038-2051页

作者： WEI Yun HUANG Wei CAO JinDe BAI WenFei TONG ShuZhen National Engineering Laboratory for Green&Safe construction Technology in urban Rail Transit Beijing 10037China Beijing urban construction design&Development Group Co. LimitedBeijing 100037China Jiangsu Provincial Key Laboratory of Networked Collective Intelligence ITS Research CenterSoutheast UniversityNanjing 210096China

The basic conception and theoretical system of smart metro are not clear and there is not a unified understanding at the academic *** on this fact,there is no guidance of the smart metro ***,this paper conducts a complete and systemic research on several basic theoretical issues of smart metro,such as the development history,concept,connotation,characteristics,evolution stages,system architecture and main construction ***,the internal and external development demands are analyzed in this *** addition,the subject-cycle-function(SCF)model of smart metro concept is ***,the essential connotation,three typical characteristics and the evolution process of smart metro are ***,the evolution relationships of main function,achievement goal,instrument subject,decision subject,control subject and factor relationship for every evolution stage are ***,according to the theory of system engineering,the three-hierarchy system architecture and five main construction contents are *** both can be used to construct the technical system of smart metro at the academic level,and provide theoretical support and technical guidance for promoting the development of smart metro construction in china.

关键词： smart metro basic theory issues system architecture

Glia-to-neuron reprogramming to the rescue?

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Neural Regeneration research 2025年第5期20卷 1395-1396页

作者： Jack W.Hickmott Cindi M.Morshead Department of Surgery University of TorontoTorontoONCanada Donnelly Centre for Cellular and Biomolecular research TorontoONCanada institute of Biomedical Engineering University of TorontoTorontoONCanada The KITE research institute Toronto Rehabilitation InstituteUniversity Health NetworkTorontoONCanada

Over the last two decades,the dogma that cell fate is immutable has been increasingly challenged,with important implications for regenerative *** brea kth rough discovery that induced pluripotent stem cells could be generated from adult mouse fibroblasts is powerful proof that cell fate can be *** exciting extension of the discovery of cell fate impermanence is the direct cellular reprogram ming hypothesis-that terminally differentiated cells can be reprogrammed into other adult cell fates without first passing through a stem cell state.

关键词： programming passing proof

Case study on the seismic response of a subway station combined with a flyover

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Underground Space 2021年第6期6卷 665-677页

作者： Qi Wang Ping Geng Xiangyu Guo Xinqiang Wang Peisong Li Bingbing Zhao Key Laboratory of Transportation Tunnel Engineering Ministry of EducationSouthwest Jiaotong UniversityChengduSichuan 610031China china Railway construction Bridge Engineering Bureau Group No.2 Engineering Co. LtdShenzhenGuangdong 518083China Tianjin Municipal Engineering design&research institute Tianjin 300392China

With the rapid development of urban traffic networks,subway stations will inevitably be constructed close to other structures in the *** subject of this study is a new subway station in china,combined with a flyover standing on the roof,owing to its unique structural *** on the time history-analysis method,the dynamic responses of the subway station,piers,and piles under seismic conditions were *** results show that the internal force and deformation of the underground structure vary under seismic excitation in different directions and are more dangerous in the under transverse excitation than under longitudinal ***,the dynamic response of the underground structure is severe under the action of low-frequency-rich Wenchuan waves,and the resonance effect is *** load of the bridge was found to inhibit the deformation of the underground structure to a certain ***,the mid-pillar and slab-mid-pillar connections are the weakest parts,and special attention should be paid to their seismic ***,the piers and piles can maintain good working condition under the action of an earthquake with the peak acceleration of 0.1g.

关键词： Subway station Time-history analysis Seismic design Spectrum characteristics Integrated structure

Sequence-activated chemiluminescence probes: programmable illumination for high-contrast in vivo sensing and imaging

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Science china Chemistry 2025年第01期 26-34页

作者： Yutao Zhang Juan Li Wei-Hong Zhu Zhiqian Guo Shanghai Key Laboratory of Functional Materials Chemistry Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Institute of Fine Chemicals School of Chemistry and Molecular Engineering East China University of Science and Technology State Key Laboratory of Bioreactor Engineering Shanghai Frontier Science Research Base of Optogenetic Techniques for Cell MetabolismEast China University of Science & Technology

Sequence-activated chemiluminescence(CL) technique offers a unique approach to detecting specific biomolecules or cellular events with high sensitivity and spatial resolution. The fundamental principle behind sequence-activated CL probes involves tailoring highly-controllable CL signals in response to specific sequences or events of interest, thus enabling high-contrast signals under complex physiological conditions. This sequential activation could be triggered by enzymes, reactive oxygen species(ROS), biothiols or changes in the microenvironment. These unique sequence-activated CL probes bestow several advantages, including minimal background, deep-tissue penetration, and the ability of non-invasive or minimally invasive detection. The sequence-activated CL techniques represent a significant advancement in molecular imaging and diagnostics. In this mini-review, we focus on the latest developments in sequential CL probes, addressing the technical challenges and discussing the future trajectory by harnessing CL signaling and molecular recognition.

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Engineering atomic Rb-N configurations to tune radical pathways for highly selective photocatalytic H2O2 synthesis coupled with biomass valorization

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Journal of Energy Chemistry 2025年第1期100卷 215-225页

作者： Jiaye Li Shuang Pan Yihuang Chen Qiong Liu College of Chemistry and Materials Engineering Wenzhou University Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology (china) Institute of Analysis Guangdong Academy of Sciences (China National Analytical CenterGuangzhou)

Photocatalytic oxygen reduction for hydrogen peroxide （H2O2） synthesis presents a green and costeffective production ***,achieving highly selective H2O2synthesis remains challenging,necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative ***,we report for the visible light-driven simultaneous co-photocatalytic reduction of O2to H2O2and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride（CNRb）.The optimized CNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h-1for H2O2generation and photooxidation rate of 3.75 mM h-1for furfuryl alcohol to furoic acid,achieving a remarkable solar-to-chemical conversion （SCC） efficiency of up to 2.27%.Experimental characterizations and DFT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical *** is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2adsorption and reinforce the capability to extract protons,thereby triggering a high selective redox product *** study holds great potential in precisely regulating reactive radical processes at the atomic level,thereby paving the way for efficient synthesis of H2O2coupled with biomass valorization.

关键词： Atomic economy Radical pathway regulation Rubidium atom coordination Biomass valorization

Influence of disturbance degree on the propped excavation stability in sandy soil in Shenyang,china

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Underground Space 2023年第3期10卷 150-165页

作者： Jiachao Dong Chen Chen Manman Dong Bo Lu Yongping Guan Wen Zhao School of Resources and Civil Engineering Northeastern UniversityShenyang 110819China Northeast Architectural design&research institute Co.Ltd Shenyang 110003China Department of Engineering Management Changshu Institute of TechnologyChangshu 215500China Taizhou Transportation Investment Group Taizhou 318000China

The stability of deep excavation is often investigated through numerical ***,most constitutive models cannot take into account the influence of disturbance on soil response,especially for excavations in sandy *** this study,the conventional Dun-can–Chang constitutive model is modified based on the data obtained from a series of triaxial consolidated drained tests on medium coarse sand with different relative densities,where all input parameters in the model are correlated with the changes in relative density due to *** modified hyperbolic model is then implemented in the general-purpose finite element code,*** effi-ciency of the proposed constitutive mode is demonstrated by comparing with the experimental ***,a case study of a large-scale propped excavation for a subway station in Shenyang is analyzed through numerical calculations with the conventional Mohr–Cou-lomb model and the proposed hyperbolic model,and theoretical derivations based on the current technical code in *** is found that the proposed approach can provide reasonable estimations compared with field measurements with a maximum error of 28%for max-imum horizontal displacement of the solider pile and of 8%for maximum ground surface settlement,whereas the other techniques over-estimate the behaviour of deep excavation significantly by more than 90%.

关键词： Propped excavation Triaxial tests Constitutive model Disturbance degree Numerical analysis

Numerical Simulation and Experimental research on Indoor Environment Separated with Down-Feed Air Curtain

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Transactions of Tianjin University 2009年第1期15卷 65-69页

作者：郭春梅张于峰常茹王晓东 School of Environmental Science and Engineering Tianjin University Energy and Mechanical Engineering Department Tianjin Urban Construction Institute Tianjin urban design institute

Indoor environment separated with down-feed air curtain was numerically simulated and experimen-tally researched. Indoor airflow and temperature fields separated with air curtain were numerically simulated. Re-sults show that both polluted airflow and thermal air current can be separated with a down-feed air curtain to pre-vent contaminants from spreading in the room space. In a test chamber, the smoke of burning Tibetan incense served as the source of contaminants, and the probe test shows that 1.0 μm is the prevailing diameter of the smoke particles. During the release of the smoke, the particle concentration of the indoor air was tested with a laser particle counter at the points of three different heights from the floor when the air curtain was running or not. Experimental results show that the higher the test point is located, the lower the particle concentration is, implying that the sepa-rating or isolating effect decreases as the air velocity of the curtain reduces along with the height descends. Accord-ing to both simulation and experimental results, down-feed air curtain can separate indoor environment effectively when the supply air velocity of air curtain is not less than 3 m/s. In order to strengthen separation effect, it is sug-gested that the supply air velocity be speeded up to 5 m/s.

关键词： air curtain airflow field temperature field particle concentration numerical simulation test chamber

Geographical Differences and Influencing Factors of Rural Energy Consumption in Southwest Mountain Areas in china:A Case Study of Zhaotong City

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Journal of Mountain Science 2012年第6期9卷 842-852页

作者： SUN Wei HAN Xiaoxu SHENG Kerong FAN Jie institute of Geographic Sciences and Natural Resources research Chinese Academy of SciencesBeijing 100101China Key Laboratory of Regional Sustainable Development Modeling Chinese Academy of SciencesBeijing 100101China china urban construction design and research institute Beijing 100120China Shandong University of Technology Shandong 255049China

china is a mountainous country,and Southwest mountain areas cover the most mountain areas in china and have the most serious *** Zhaotong city as the study area,based on 902 rural household questionnaires of 11 villages in 2 counties and Tobit model,this paper analyzes the geographical differences and influencing factors of energy consumption for non-production purposes of rural households living in different terrain *** research finds that:(1) Coal takes up the main part of energy consumption in valley areas and coal consumption is mainly affected by per capita cultivated land area,household income,proportion of rural household energy expenditure in total expenditure,coal price,and family population *** takes up the main part of energy consumption in high mountain areas and firewood consumption is mainly affected by per capita firewood forest area,distance to purchase coal,household income,electricity price,and coal price.(2) Only when the distance is greater than 20 kilometers,that is the average distance of rural households living in middle mountain areas(1,600m^1,800m) to purchase coal,the transportation condition has a significant impact on coal consumption.(3) In high mountain areas,prices of coal and electricity are the main factors influencing energy consumption choice of rural *** high prices of coal and electricity would to some extent lead rural households to choose firewood as the main energy consumption *** to coal,rural households prefer to choose electricity.

关键词： Southwest mountain areas Sustainable livelihoods Energy for non-production purposes Terrain