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Science China Mathematics 2024年第3期67卷 627-646页

作者： Hui Xiao ion grama quansheng liu Institut fur Mathematik und Angewandte Informatik Universitat HildesheimHildesheim 31141Germany Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China LMBA Universite Bretagne SudCNRS UMR 6205Vannes F-56000France

Let(g_(n))_(n≥1) be a sequence of independent and identically distributed positive random d×d matrices and consider the matrix product G_(n)=g_(n)…g_*** suitable conditions,we establish the Berry-Esseen bounds on the rate of convergence in the central limit theorem and Cramer-type moderate deviation expansions,for any matrix norm ‖G_(n)‖ of G_(n),its entries G_(n)^(i,j) and its spectral radius ρ(G_(n)).Extended versions of their joint law with the direction of the random walk G_(n)x are also established,where x is a starting point in the unit sphere of R~d.

关键词： Berry-Esseen bound Cramér-type moderate deviation product of random matrices operator norm entry spectral radius

Cross-scale mechanical softening of Marcellus shale induced by CO_(2)-water-rock interactions using nanoindentation and accurate grain-based modeling

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Underground Space 2024年第6期19卷 26-46页

作者： Yiwei liu quansheng liu Zhijun Wu Shimin liu Yong Kang Xuhai Tang School of Civil Engineering Wuhan UniversityWuhan 430072China Department of Energy and Mineral Engineering G3 Center and EMS Energy InstituteThe Pennsylvania State UniversityUniversity ParkPA 16802USA School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China

Mechanical softening behaviors of shale in CO_(2)-water–rock interaction are critical for shale gas exploitation and CO_(2)*** work investigated the cross-scale mechanical softening of shale triggered by CO_(2)-water–rock ***,the mechanical softening of shale following 30 d of exposure to CO_(2)and water was assessed at the rock-forming mineral scale using *** mechanical alterations of rock-forming minerals,including quartz,muscovite,chlorite,and kaolinite,were analyzed and ***,an accurate grain-based modeling(AGBM)was proposed to upscale the nanoindentation *** models were generated based on the real microstructure of shale derived from TESCAN integrated minerals analyzer(TIMA)digital *** parameters of shale minerals determined by nanoindentation served as input material properties for ***,numerical simulations of uniaxial compression tests were conducted to investigate the impact of mineral softening on the macroscopic Young’s modulus and uniaxial compressive strength(UCS)of *** results present direct evidence of shale mineral softening during CO_(2)-water–rock interaction and explore its influence on the upscale mechanical properties of *** paper offers a microscopic perspective for comprehending CO_(2)-water-shale interactions and contributes to the development of a cross-scale mechanical model for shale.

关键词： Shale Cross-scale modeling Nanoindentation CO_(2)-water-rock interaction Mechanical softening

Effects of seepage pressure on the mechanical behaviors and microstructure of sandstone

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2033-2051页

作者： Xuewei liu Juxiang Chen Bin liu Sai Wang quansheng liu Jin Luo State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Faculty of Engineering China University of GeosciencesWuhan430074China Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China

Surrounding rocks of underground engineering are subjected to long-term seepage pressure,which can deteriorate the mechanical properties and cause serious *** order to understand the impact of seepage pressure on the mechanical property of sandstone,uniaxial compression tests,P-wave velocity measurements,and nuclear magnetic resonance(NMR)tests were conducted on saturated sandstone samples with varied seepage pressures(i.e.0 MPa,3 MPa,4 MPa,5 MPa,6 MPa,7 MPa).The results demonstrate that the mechanical parameters(uniaxial compressive strength,peak strain,elastic modulus,and brittleness index),total energy,elastic strain energy,as well as elastic strain energy ratio,decrease with increasing seepage pressure,while the dissipation energy and dissipation energy ratio ***,as seepage pressure increases,the micro-pores gradually transform into meso-pores and *** increases the cumulative porosity of sandstone and decreases P-wave *** numerical results indicate that as seepage pressure rises,the number of tensile cracks increases progressively,the angle range of microcracks is basically from 50-120to 80-100,and as a result,the failure mode transforms to the tensile-shear mixed failure ***,the effects of seepage pressure on mechanical properties were *** results show that decrease in the effective stress and cohesion under the action of seepage pressure could lead to deterioration of strength behaviors of sandstone.

关键词： Rock mechanics Mechanical property Seepage pressure Numerical simulation Microcracks

Anisotropic shearing mechanism of Kangding slate:Experimental investigation and numerical analysis

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1487-1504页

作者： Ping liu quansheng liu Penghai Deng Yucong Pan Yiming Lei Chenglei Du Xianqi Xie The Key Laboratory of Geotechnical and Structural Engineering Safety of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

The shear mechanical behavior is regarded as an essential factor affecting the stability of the surrounding rocks in underground *** shear strength and failure mechanisms of layered rock are significantly affected by the foliation *** shear tests were conducted on cubic slate samples with foliation angles of 0°,30°,45°,60°,and 90°.The effect of foliation angles on failure patterns,acoustic emission(AE)characteristics,and shear strength parameters was *** on AE characteristics,the slate failure process could be divided into four stages:quiet period,step-like increasing period,dramatic increasing period,and remission period.A new empirical expression of cohesion for layered rock was proposed,which was compared with linear and sinusoidal cohesion expressions based on the results made by this paper and previous *** comparative analysis demonstrated that the new expression has better prediction ability than other *** proposed empirical equation was used for direct shear simulations with the combined finite-discrete element method(FDEM),and it was found to align well with the experimental *** both computational efficiency and accuracy,it was recommended to use a shear rate of 0.01 m/s for FDEM to carry out direct shear *** balance the relationship between the number of elements and the simulation results in the direct shear simulations,the recommended element size is 1 mm.

关键词： Anisotropy Empirical expression of cohesion foliation angles Combined finite-discrete element method(FDEM) Shear rate Element size

Numerical investigation of geostress influence on the grouting reinforcement effectiveness of tunnel surrounding rock mass in fault fracture zones

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 81-101页

作者： Xiangyu Xu Zhijun Wu Lei Weng Zhaofei Chu quansheng liu Yuan Zhou The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China Wuhan University Shenzhen Research Institute Shenzhen518057China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan430071China

Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by *** this study,a numerical manifold method(NMM)based simulator has been developed to examine the impact of geostress conditions on grouting reinforcement during tunnel *** develop this simulator,a detection technique for identifying slurry migration channels and an improved fluid-solid coupling(FeS)framework,which considers the influence of fracture properties and geostress states,is developed and incorporated into a zero-thickness cohesive element(ZE)based NMM(Co-NMM)for simulating tunnel ***,to simulate coagulation of injected slurry,a bonding repair algorithm is further proposed based on the ZE *** verify the accuracy of the proposed simulator,a series of simulations about slurry migration in single fractures and fracture networks are numerically reproduced,and the results align well with analytical and laboratory test ***,these numerical results show that neglecting the influence of geostress condition can lead to a serious over-estimation of slurry migration range and reinforcement *** validations,a series of simulations about tunnel grouting reinforcement and tunnel excavation in fault fracture zones with varying fracture densities under different geostress conditions are *** on these simula-tions,the influence of geostress conditions and the optimization of grouting schemes are discussed.

关键词： Numerical manifold method(NMM) Grouting reinforcement Geostress condition Fault fracture zone Tunnel excavation

Experimental study on the influences of cutter geometry and material on scraper wear during shield TBM tunnelling in abrasive sandy ground

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 410-425页

作者： Shaohui Tang Xiaoping Zhang quansheng liu Qi Zhang Xinfang Li Haojie Wang Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

When shield TBM tunnelling in abrasive sandy ground,the rational design of cutter parameters is critical to reduce tool wear and improve tunnelling ***,the influence mechanism of cutter parameters on scraper wear remains unclear due to the lack of a reliable test *** and material optimisation are often based on subjective experience,which is unfavourable for improving scraper geological *** the present study,the newly developed WHU-SAT soil abrasion test was used to evaluate the variation in scraper wear with cutter geometry,material and *** influence mechanism of cutter parameters on scraper wear has been revealed according to the scratch characteristics of the scraper *** geometry and material parameters have been optimised to reduce scraper *** results indicate that the variation in scraper wear with cutter geometry is related to the cutting resistance,frictional resistance and stress *** appropriate increase in the front angle(or back angle)reduces the cutting resistance(or frictional resistance),while an excessive increase in the front angle(or back angle)reduces the edge angle and causes stress *** optimal front angle,back angle and edge angle for quartz sand samples areα=25°,β=10°andγ=55°,*** wear resistance of the modelled scrapers made of different metal materials is related to the chemical elements and *** wear resistances of the modelled scrapers made of 45#,06Cr19Ni10,42CrMo4 and 40CrNiMoA are 0.569,0.661,0.691 and 0.728 times those made of WC-Co,*** the alloy hardness is less than 47 HRC(or greater than 58 HRC),scraper wear decreases slowly with increasing alloy hardness as the scratch depth of the particle asperity on the metal surface stabilizes at a high(or low)***,when the alloy hardness is between 47 HRC and 58 HRC,scraper wear decreases rapidly with increasing alloy hardness as the scratch depth transitions

关键词： Shield TBM Scraper wear Cutter shape Metal material Alloy hardness

Sharp large deviation results for sums of independent random variables

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Science China Mathematics 2015年第9期58卷 1939-1958页

作者： FAN XieQuan grama ion.liu quansheng Regularity Team Institut National de Recherche en Informatique et en Automatique Laboratoire de Mathmatiques Appliques aux Systèmes Ecole Centrale Paris-Grande Voie des Vignes Laboratoire de Mathmatiques de Bretagne Atlantique UMR 6205 University Bretagne-Sud School of Mathematics and Computing Science Changsha University of Science and Technology

We show sharp bounds for probabilities of large deviations for sums of independent random variables satisfying Bernstein's condition. One such bound is very close to the tail of the standard Gaussian law in certain case; other bounds improve the inequalities of Bennett and Hoeffding by adding missing factors in the spirit of Talagrand(1995). We also complete Talagrand's inequality by giving a lower bound of the same form, leading to an equality. As a consequence, we obtain large deviation expansions similar to those of Cram′er(1938),Bahadur-Rao(1960) and Sakhanenko(1991). We also show that our bound can be used to improve a recent inequality of Pinelis(2014).

关键词： Bernstein’s inequality sharp large deviations Cramér large deviations expansion of BahadurRao sums of independent random variabl

Femtosecond laser fabrication of 3D vertically aligned micro-pore network on thick-film Li_(4)Ti_(5)O_(12)electrode for high-performance lithium storage

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Journal of Energy Chemistry 2024年第8期95卷 250-262,I0006页

作者： quansheng Li Xiaofei Sun Xuesong Mei Lingzhi Wang Minxing Yang Jianlei Cui Wenjun Wang State Key Laboratory for Manufacturing System Engineering Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina Shaanxi Key Laboratory of Intelligent Robots Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina

The development of energy storage devices with high energy density relies heavily on thick film electrodes,but it is challenging due to the limited ion transport kinetics inherent in thick ***,we report on the preparation of a directional vertical array of micro-porous transport networks on LTO electrodes using a femtosecond laser processing strategy,enabling directional ion rapid transport and achieving good electrochemical performance in thick film *** three-dimensional(3D)vertically aligned micro-pore networks are innovatively designed,and the structure,kinetics characteristics,and electrochemical performance of the prepared ion transport channels are analyzed and discussed by multiple characterization and testing ***,the rational mechanisms of electrode performance improvement are studied experimentally and simulated from two aspects of structural mechanics and transmission *** ion diffusion coefficient,rate performance at 60 C,and electrode interface area of the laser-optimized 60-15%micro-porous transport network electrodes increase by 25.2 times,2.2 times,and 2.15 times,respectively than those of untreated ***,the preparation of 3D micro-porous transport networks by femtosecond laser on ultra-thick electrodes is a feasible way to develop high-energy *** addition,the unique micro-porous transport network structure can be widely extended to design and explore other high-performance energy materials.

关键词： Femtosecond laser Micro-porous transport networks Laser processing Thick film electrodes ion transport kinetics

Two-dimensional silica enhanced solid polymer electrolyte for lithium metal batteries

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Particuology 2024年第2期85卷 146-154页

作者： Zhihong Luo Weiyong Li Chong Guo Ya Song Mingxia Zhou Yan Shi Jing Xu Long Li Bin Shi quansheng Ouyang Jiao-jing Shao Guangmin Zhou School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Advanced Chemical Power Sources Zunyi563003China Graphene Materials Engineering Research Center of Guizhou Colleges and Universities Guiyang550025China Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate Schoo Tsinghua UniversityShenzhen518055China

Solid polymer electrolytes(SPEs)are promising substitutes for current flammable liquid electrolytes to achieve high-safety and high-energy-density lithium metal *** oxide(PEO)based solid polymer electrolytes have attracted increasing attention because of their excellent flexibility,manufacturability,light weight,and low-cost processing,while they often suffer from low ionic con-ductivity at room temperature,low lithium transference number and unsatisfactory interfacial resis-tance,which largely restrain their practical ***,two-dimensional holey silica nanosheets(2D-HSN)as the fillers,together with LiNO_(3) as the electrolyte additive,are introduced in a PEO/poly(-vinylidene fiuoride-co-hexafluoropropylene)(PVDF-HFP)blended polymer matrix to obtain a *** incorporation of HSN filler creates supplementary channels for lithium ion migration and lowers the crystallinity of the polymer,thereby facilitating the movement of lithium *** HSN-based SPE demonstrates higher ionic conductivity up to 3.7 x 10-4 S cm-1 at 30℃,larger Li+transference number close to 0.34,and more stable lithium plating/stripping than that without the fillers,and HSN can promote the formation of more stable solid electrolyte interphase(SEI)*** as-assembled LiFePO4||Li batteries deliver a high specific capacity of 159 mA h g-1 with the capacity retention of 95.5%after 200 cycles at 30℃,as well as superior rate performance and cycling stability compared to that using the blank SPE.

关键词： Vermiculite nanosheets Two-dimensional silica Solid polymer electrolytes FillersLithium metal batteries

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内丹学视域下扶阳学派“阳主阴从”观新探

中华中医药杂志 2024年第5期39卷 2224-2229页

作者：刘辰昊刘毅冯全生成都中医药大学成都610075

钦安卢氏扶阳学派因提出有别于传统“阴阳平衡”的“阳主阴从”阴阳观而显标新立异。考究发现这一观点的来源实出自道家内丹学思想。从钦安卢氏扶阳医学发展源流看,其与道家内丹学说的渊源联系出于槐轩,成于钦安,盛于卢氏。“阳主阴从... 详细信息

钦安卢氏扶阳学派因提出有别于传统“阴阳平衡”的“阳主阴从”阴阳观而显标新立异。考究发现这一观点的来源实出自道家内丹学思想。从钦安卢氏扶阳医学发展源流看,其与道家内丹学说的渊源联系出于槐轩,成于钦安,盛于卢氏。“阳主阴从”观早于扶阳医学理论而见于道家内丹学说之中。内丹学说认为阴阳具有不同层次。钦安卢氏基于内丹学说对阴阳的认识而尤重坎中一阳,形成了阳主阴从,用阳化阴的理论认识,并在药物运用上一以贯之。“阳主阴从”观的实质是以先天真阳为主导,气血精津液等后天阴阳为从属,包含着先天统领后天的主从关系。重阳的理念是对通于天道的境界追求。故可认为钦安卢氏扶阳学派更近于“道医”而有别于其他中医学派。

关键词：钦安卢氏扶阳医学内丹学说道医阳主阴从