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Dynamic impact properties of deep sandstone under thermal-hydraulicmechanical coupling loads

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Journal of mountain Science 2024年第6期21卷 2113-2129页

作者： cao Chunhui DING Haonan ZOU Baoping School of Civil Engineering and Architecture Zhejiang University of Science and TechnologyHangzhou 310023China Zhejiang-Singapore Joint Laboratory for Urban Renewal and Future City Hangzhou 310023China

The deep rock mass within coal mines situated in a challenging environment are characterized by high ground stress,high geotemperature,high osmotic water pressure,and dynamic disturbances from mechanical *** investigate the impact of this complex mechanical environment on the dynamic characteristics of roof sandstone in self-formed roadways without coal pillars,standard specimens of deep sandstone from the 2611 upper tunnel working face of the Yongmei Company within the Henan Coal Chemical Industry Group in Henan,China were prepared,and an orthogonal test was *** a self-developed geotechnical dynamic impact mechanics test system,triaxial dynamic impact tests under thermal-hydraulicmechanical coupling conditions were conducted on deep *** results indicate that under high confining pressure,deep sandstone exhibits pronounced brittle failure at low temperatures,with peak strength gradually decreasing as temperature and osmotic water pressure ***,under low confining pressure and low temperature,the brittleness of deep sandstone weakens gradually,while ductility ***,sandstone demonstrates higher peak strength at low temperatures under high axial pressure conditions,lower peak strength at high temperatures,and greater strain under low axial pressure and high osmotic water *** in impact air pressure and osmotic water pressure have proportionally greater effects on peak stress and peak *** 50%of the input strain energy is utilized as effective energy driving the sandstone fracture *** analysis identifies the optimal combination of factors affecting the peak stress and peak strain of *** the coupling effect,intergranular and transgranular fractures occur within the *** images illustrate that the damage forms range from minor damage with multiple fissures to extensive fractures and severe *** study elucidates the varied dynamic impact me

关键词： Deep sandstone Thermal-hydraulicmechanical coupling Dynamic impact Stress-strain Failure modes Polar analysis

Numerical study of the influence of the atmospheric pressure on the thermal environment in the passenger cabin

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Building Simulation 2024年第2期17卷 253-265页

作者： Xin Su Yu Guo Zhengwei Long Yi cao Tianjin Key Lab.of Indoor Air Environmental Quality Control School of Environmental Science and EngineeringTianjin UniversityTianjin300072China Shanghai Aircraft Design and Research Institute Jinke RoadPudong DistrictShanghai201210China

The cabin air pressure remains lower than the horizontal atmospheric pressure when the airplane is in *** pressure is one of the parameters that must be taken into consideration while studying the thermal environment of an airplane *** are still no reference values for aircraft cabins despite the fact that numerous studies on low pressure heat transfer have demonstrated the connection between convective heat transfer coefficient(CHTC)and air *** this paper,a correction method for CHTC under low pressure conditions was established by using the dummy heat dissipation in the low-pressure cabin *** this basis,a thermal environment simulation model was developed,then was applied to the simulation of a seven-row aircraft cabin containing 42 passengers,and the CHTC and heat loss of dummy surface in the cabin were ***,the results of PmV calculated by using heat dissipation and air parameters at sampling points were *** results show that the modified CHTC can accurately reflect the cabin thermal environment under low pressure conditions,and the correction of CHTC can be realized by adjusting the turbulent Prandtl number,which is nonlinear correlated with the *** simulation results of the thermal environment in the seven-row cabin show that the CHTC changes by about 42%before and after *** air pressure decreases during take-off,which reduces the average CHTC of the crew surface from 5.09 W/(m^(2)·K)to 4.56 W/(m^(2)·K),but the air temperature rises by about 0.2°C as a *** deviation of PmV results calculated by using simulated heat loss data and using air parameters of measuring points in space is up to 0.5,but the latter is representative for calculating the thermal comfort level of the whole cabin.

关键词： low pressure aircraft cabin simulation heat dissipation convective heat transfer coefficient

Fixed-Time Gradient Flows for Solving Constrained Optimization: A Unified Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1849-1864页

作者： Xinli Shi Xiangping Xu Guanghui Wen Jinde cao School of Cyber Science and Engineering Southeast UniversityNanjing 210096China School of mathematics Southeast UniversityNanjing 210096China

The accelerated method in solving optimization problems has always been an absorbing *** on the fixedtime(FxT)stability of nonlinear dynamical systems,we provide a unified approach for designing FxT gradient flows(FxTGFs).First,a general class of nonlinear functions in designing FxTGFs is provided.A unified method for designing first-order FxTGFs is shown under Polyak-Łjasiewicz inequality assumption,a weaker condition than strong *** there exist both bounded and vanishing disturbances in the gradient flow,a specific class of nonsmooth robust FxTGFs with disturbance rejection is *** the strict convexity assumption,Newton-based FxTGFs is given and further extended to solve time-varying ***,the proposed FxTGFs are further used for solving equation-constrained ***,an FxT proximal gradient flow with a wide range of parameters is provided for solving nonsmooth composite *** show the effectiveness of various FxTGFs,the static regret analyses for several typical FxTGFs are also provided in ***,the proposed FxTGFs are applied to solve two network problems,i.e.,the network consensus problem and solving a system linear equations,respectively,from the perspective of ***,by choosing component-wisely sign-preserving functions,these problems can be solved in a distributed way,which extends the existing *** accelerated convergence and robustness of the proposed FxTGFs are validated in several numerical examples stemming from practical applications.

关键词： Consensus constrained optimization disturbance rejection linear equations fixed-time gradient flow(FxTGF).

Fluid-solid coupling numerical simulation of micro-disturbance grouting treatment for excessive deformation of shield tunnel

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Underground Space 2024年第6期19卷 87-100页

作者： Yanjie Zhang Zheng cao Chun Liu Hongwei Huang College of Civil Engineering and Architecture Henan University of TechnologyZhengzhou 450001China School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China Key Laboratory of Geotechnical and Underground Engineering of ministry of Education Tongji UniversityShanghai 200092China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

micro-disturbance grouting is a recovery technique to reduce the excessive deformation of operational shield tunnels in urban *** grout mass behaves as a fluid in the ground before hardening to form a grout–soil mixture,which highlights the necessity of using fluid–solid coupling method in the simulation of grouting *** a discrete element modeling environment,this paper proposes a novel fluid-solid coupling method based on the pore density flow *** demonstrate the effectiveness of this method,it is applied to numerical simulation of micro-disturbance grouting process for treatment of large transverse deformation of a shield tunnel in Shanghai metro,*** simulation results reveal the mechanism of recovering tunnel convergence by micro-disturbance grouting in terms of compaction and fracture of soil,energy analysis during grouting,and mechanical response of soil-tunnel interaction ***,the influence of the three main grouting parameters(i.e.,grouting pressure,grouting distance,and grouting height)on tunnel deformation recovery efficiency is evaluated through parametric *** order to efficiently recover large transverse deformation of shield tunnel in Shanghai metro,it is suggested that the grouting pressure should be about 0.55 mPa,the grouting height should be in the range of 6.2–7.0 m,and the grouting distance should be in the range of 3.0–3.6 *** results provide a valuable reference for grouting treatment projects of over-deformed shield tunnel in soft soil areas.

关键词： Fluid-solid coupling Discrete element method Pore density flow micro-disturbance grouting Soil-tunnel interaction

Dietary long-chain fatty acid metabolism boosts antitumorimmune response

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Cancer Communications 2024年第5期44卷 580-583页

作者： Jiaming Wang Xuetao cao Department of Immunology Institute of Basic Medical SciencesPeking Union Medical CollegeChinese Academy of Medical SciencesBeijingP.R.China Institute of Immunology College of Life SciencesNankai UniversityTianjinP.R.China

Overcoming resistance to immune checkpoint blockade(ICB)therapy will pave the way for effective ICB cancer immunotherapy since a large proportion of cancer patients are not responsive to ICB immunotherapy[1].The molecular mechanisms of ICB resistance are diverse,including tumor-intrinsic resistant factors(such as genetic and epigenetic disorders),immunosuppressive/disabled factors(such as T cell exhaustion),and environmental restrictive factors(such as neuroendocrine stress and metabolic reprogramming).

关键词： metabolism cancer immune

Generation of polarized electron beams through self-injection in the interaction of a laser with a pre-polarized plasma

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High Power Laser Science and Engineering 2024年第3期12卷 62-68页

作者： L.R.Yin X.F.Li Y.J.Gu N.cao Q.Kong m.Büscher S.m.Weng m.Chen Z.m.Sheng Key Laboratory of Nuclear Physics and Ion-beam Application(moE) Institute of Modern PhysicsDepartment of Nuclear Science and TechnologyFudan UniversityShanghaiChina State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghaiChina SANKEN(Institute of Scientific and Industrial Research) Osaka UniversityOsakaJapan Sichuan Research Institute Shanghai Jiao Tong UniversityChengduChina Peter Grünberg Institut(PGI-6) Forschungszentrum JülichJülichGermany Institut für Laser-und Plasmaphysik Heinrich-Heine-Universität DüsseldorfDüsseldorfGermany Key Laboratory for Laser Plasmas(moE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghaiChina Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghaiChina Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghaiChina

Polarized electron beam production via laser wakefield acceleration in pre-polarized plasma is investigated by particlein-cell *** evolution of the electron beam polarization is studied based on the Thomas±Bargmann±michel±Telegdi equation for the transverse and longitudinal self-injection,and the depolarization process is found to be influenced by the injection *** the case of transverse self-injection,as found typically in the bubble regime,the spin precession of the accelerated electrons is mainly influenced by the ***,in the case of longitudinal injection in the quasi-1D regime(for example,*** et al.,***.110,135002(2013)),the direction of electron spin oscillates in the laser *** the electrons move around the laser axis,the net influence of the laser field is nearly zero and the contribution of the wakefield can be ***,an ultra-short electron beam with polarization of 99%can be obtained using longitudinal self-injection.

关键词： laser wakefield acceleration longitudinal self-injection particle-in-cell simulation polarized electron beam

Impact pressure of waves generated by landslides on bank slopes

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Journal of mountain Science 2024年第3期21卷 918-931页

作者： cao Ting WANG Pingyi QIU Zhenfeng LIU Jie Key Laboratory of Hydraulic and Waterway Engineering of ministry of Education Chongqing Jiaotong UniversityChongqing 400074China Engineering Research Center of Diagnosis Technology and Instruments of Hydro-Construction Chongqing Jiaotong UniversityChongqing 400074China

Impulse waves that are generated by landslides in narrow reservoir areas threaten the stability of buildings and bank *** discuss the action process and evolution law of the wave pressure on bank slopes,a three-dimensional physical model test that considers impulse waves generated by landslides was performed,and factors including landslide width,thickness,slope angles of the sliding surface,and bank slope angle were *** on wave forms on the bank slopes,wave pressure curve characteristics,and peak value,the action process of wave pressure could be divided into the following stages:maximum pulsating pressure stage,wave impact stage(when waves break),and stationary pulsation *** was found that wave breaking is dependent on the value of the surf similarity parameterξ.The distribution pattern of impact pressure decays linearly on both sides of the maximum impact pressure point,and the attenuation degree decreases when it attains 40%of the maximum ***,it is proposed that the prediction formula for the maximum effective impact pressure of the bank slope be related to the reciprocal of wave steepness,relative water depth,and slope *** prediction formula provides strong theoretical support for early safety warning and for predicting the bank slope under impulse waves generated by landslides.

关键词： model test Impact pressure Action stage Breaking discrimination Distribution model

Ionic Liquid-Enhanced Assembly of Nanomaterials for Highly Stable Flexible Transparent Electrodes

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Nano-micro Letters 2024年第7期16卷 441-455页

作者： Jianmin Yang Li Chang Xiqi Zhang Ziquan cao Lei Jiang Key Laboratory of Bio-Inspired materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China College of Chemistry and Chemical Engineering Chongqing University of TechnologyChongqing 400054People’s Republic of China Binzhou Institute of Technology Binzhou 256600People’s Republic of China Nanomics Biotechnology Co. Ltd.HangzhouPeople’s Republic of China

The controlled assembly of nanomaterials has demon-strated significant potential in advancing technological ***,achieving highly efficient and low-loss assembly technique for nanomate-rials,enabling the creation of hierarchical structures with distinctive func-tionalities,remains a formidable ***,we present a method for nanomaterial assembly enhanced by ionic liquids,which enables the fabrication of highly stable,flexible,and transparent electrodes featuring an organized layered *** utilization of hydrophobic and non-volatile ionic liquids facilitates the production of stable interfaces with water,effectively preventing the sedimentation of 1D/2D nanomaterials assembled at the ***,the interfacially assembled nanomaterial monolayer exhibits an alternate self-climbing behavior,enabling layer-by-layer transfer and the formation of a well-ordered mXene-wrapped silver nanowire network *** resulting composite film not only demonstrates exceptional photoelectric performance with a sheet resistance of 9.4Ωsq^(-1) and 93%transmittance,but also showcases remarkable environmental stability and mechanical *** noteworthy is its application in transparent electromagnetic interference shielding materials and triboelectric nanogenerator *** research introduces an innovative approach to manufacture and tailor functional devices based on ordered nanomaterials.

关键词： Ionic liquids Assembly Silver nanowires mXene nanosheets Flexible transparent electrodes

Characterization of size-resolved effective density of atmospheric particles in an urban atmosphere in Southern China

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Journal of Environmental Sciences 2024年第7期141卷 194-204页

作者： Tingting Xie Liming cao Jinyi Zheng Peng Xuan Xiaofeng Huang Laboratory of Atmospheric Observation Supersite School of Environment and EnergyPeking University Shenzhen Graduate SchoolShenzhen 518055China

Effective density(ρ_(eff))is one of the most important physical properties of atmospheric particles,providing important references in exploring the emissions and aging processes of fresh *** this study,a combined system of differential mobility analyzer,centrifugal particle mass analyzer,and condensation particle counter was used to periodically measure theρ_(eff)of atmospheric particles in Shenzhen from Oct.2021 to *** showed that theρ_(eff)of particles with various size presented a bimodal distribution,which could be divided into main density(ρ_(m),main peak,corresponding to relatively dense particles after aging)and sub density(ρ_(s),sub peak,corresponding to fresh particles).The occurrence frequencies ofρ_(s)of particles with diameters of 50 and 80 nm were less than 20%,but were as high as about 40%of that with diameters from 120 to 350 ***ρ_(m)showed increasing trend with the size of particles,whileρ_(s)decreased as the increasing of the size of ***ρ_(eff)on pollution day varied significantly with chemical *** increasing of the proportion of sulfate could promote the increasing ofρ_(eff),while black carbon and organic matter caused opposite effects,which may be related to various factors,including the difference of the material density and morphology of various chemical ***ρ_(eff)of 50,80 and 120 nm particles decreased considerably during the new particle formation event,indicating that organic condensation was an important contributor to new particle growth.

关键词： DmA-CPmA-CPC Effective density main/sub density Size distribution