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Mechanical behavior and damage constitutive model of sandstone under hydro-mechanical (h-M) coupling

International Journal of Mining Science and Technology 2024年第6期34卷 837-853页

作者： Tao Tan Chunyang Zhang Yanlin zhao Xiaoshuang Li School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Safety and health in Metal Mines Maanshan 243000China Sinosteel Maanshan General Institute of Mining Research Co. Ltd.Maanshan 243000China School of Resource&Environment and Safety Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Urban Construction Changzhou UniversityChangzhouJiangsu 213164China

Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under h-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under h-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under h-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to h-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under h-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and h-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under h-M coupling, overcome the inconvenience of existing D-C models

关键词： h-M coupling Water-saturated sandstone Mechanical mechanism Energy evolution D-C model

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Piezoelectric composite hydrogel with wireless electrical stimulation enhances motor functional recovery of spinal cord injury

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Journal of Materials Science & Technology 2024年第5期172卷 228-239页

作者： Zehao Li Guanlin Li Xinyu Wang Zheng zhao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Sanya Science and Education Innovation Park of Wuhan University of Technology Sanya 572000China

Electrical stimulation(ES)can restore motor function after spinal cord injury(SCI).however,traditional intraspinal ES has many disadvantages,such as the need for a complex circuitry device,an external power source,and a second surgery to remove the *** materials have received increasing at-tention due to their potential to convert ambient mechanical energy into ES without an external power source or implantation of ***,a novel polydopamine(PDA)coated barium titanate(BaTiO_(3))nanoparticles(BaTiO_(3)@PDA)incorporated silk fibroin(SF)hydrogel(SFBT)was *** SFBT hy-drogel was crosslinked by horseradish peroxidase(hRP)/hydrogel peroxide(h_(2)O_(2))to integrate the piezo-electric potency of BaTiO_(3)with the thermal sensitivity of hRP/h_(2)O_(2)for SCI *** hydrogel con-taining 5%(w/v)BaTiO_(3)@PDA nanoparticles(SFBT-5),which was selected for in vivo study,exhibited a short gelation time(5 min),suitable storage modulus(925±35 Pa),and wireless ES(average current of 124 nA).Moreover,Basso-Beattie-Bresnahan(BBB)scores test and footprint analysis demonstrated that the SFBT-5 hydrogel successfully enhanced motor functional recovery of *** histopathological assess-ments,the SFBT-5 hydrogel significantly accelerated spinal cord healing,as indicated by smaller lesion cavities(∼16.7%of the SCI group).Meanwhile,the SFBT-5 hydrogel accelerated neurogenesis,facilitated axon regrowth and synapse formation,and promoted ***,this study highlights the potential of piezoelectric hydrogels for SCI regeneration.

关键词： Silk fibroin Barium titanate Piezoelectric hydrogel Spinal cord injury Electrical stimulation

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Plasma-assisted synthesis of porous bismuth nanosheets for electrocatalytic CO_(2)-to-formate reduction

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Journal of Energy Chemistry 2024年第7期94卷 19-28页

作者： Liangping Xiao Qizheng Zheng Rusen Zhou Sifan Liu Yifan zhao Yadong zhao Renwu Zhou Kostya Ken Ostrikov State Key Laboratory of Electrical Insulation and Power Equipment Centre for Plasma BiomedicineSchool of Electrical EngineeringXi'an Jiaotong UniversityXi'an 710049 ShaanxiChina School of Chemistry and Physics QUT Centre for Materials ScienceQueensland University of Technology(QUT)BrisbaneQLD 4000.Australia Department of Physics Research Institute for Biomimetics and Soft MatterFujian Provincial Key Laboratory for Soft Functional MaterialsJiujiang Research InstituteXiamen UniversityXiamen361005FujianChina Department of Biomaterials College of MaterialsXiamen UniversityXiamen 361005FujianChina School of Food and Pharmacy Zhejiang Ocean UniversityZhoushan 316022ZhejiangChina

The electrochemical carbon dioxide reduction(eCO_(2)RR)to formate,driven by clean energy,is a promising approach for producing renewable chemicals and high-value *** its potential,further development faces challenges due to limitations in electrocatalytic activity and durability,especially for nonnoble metal-based ***,naturally abundant bismuth-based nanosheets that can effectively drive CO_(2)-to-formate electrocatalytic reduction are prepared using the plasma-activated Bi_(2)Se_(3) followed by a reduction ***-obtained plasma-activated Bi nanosheets(P-BiNS)feature ultrathin structures and high surface *** nanostructures ensure the P-BiNS with outstanding eCO_(2)RR catalytic performance,highlighted by the current density of over 80 mA cm^(-2) and a formate Faradic efficiency of>90%.Furthermore,P-BiNS catalysts demonstrate excellent durability and stability without deactivation following over 50h of *** selectivity for formate production is also studied by density functional theory(DFT)calculations,validating the importance and efficacy of the stabilization of intermediates(^(*)OChO)on the P-BiNS *** study provides a facile plasma-assisted approach for developing high-performance and low-cost electrocatalysts.

关键词： Plasma-assisted synthesis Plasmaa ctivation Bismuth nanosheet CO_(2)RR Formate

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heterocatalytic ethylene methoxycarbonylation via a pseudo-hydride pathway over Pt_(1)/MoS_(2)

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Science China Chemistry 2024年第8期67卷 2427-2428页

作者： Bo-hang zhao Bin Zhang Institute of Molecular Plus Department of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China

Ethylene (C2h4) methoxycarbonylation (EMC) with CO and methanol (Ch3Oh) to methyl propanoate (MP) is industrially important due to its 100% atom efficiency [1].however, the heavy reliance on homogeneous Pd-based catalysts and strong acid media over commercial EMC processes still causes economic and environmental concerns [2]. At present, supported single-atom catalysts (SACs) can serve as bridges for accessing homogeneous catalysts in traditional heterogeneous catalytic processes.

关键词： processes. catalytic hydride

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Mode Switching and Consistency Control for Electric-hydraulic hybrid Steering System

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Automotive Innovation 2024年第1期7卷 166-181页

作者： Zhongkai Luan Wanzhong zhao Chunyan Wang College of Energy and Power Engineering 29 Yudao St.Nanjing 210016China

Electric-hydraulic hybrid power steering(E-hhPS)system,a novel device with multiple modes for commercial electric vehicles,is designed to realize both superior steering feel and high energy ***,inconsistent steering perfor-mance occurs in the mode-switching process due to different dynamic characteristics of electric and hydraulic components,which even threatens driving *** this paper,mode-switching strategy and dynamic compensation control method are proposed for the E-hhPS system to eliminate the inconsistency of steering feel,which comprehensively considers ideal assistance characteristics and energy consumption of the ***,the influence of disturbances on system stability is analyzed,and h_(∞)robust controller is employed to guarantee system robustness and *** experimental results dem-onstrate that the proposed strategy can provide a steering system with natural steering feel without apparent inconsistency and effectively minimize energy consumption.

关键词： hydraulic hybrid steering system Steering feel Consistency Mode switch Robust control

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A high-performance lithium anode based on N-doped composite graphene

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Rare Metals 2024年第3期43卷 1030-1036页

作者： Can Jiao hao-Bo Sun Li Zhang Shang-Qian zhao Guo-Yao Pang Chun-Rong zhao Shi-Gang Lu General Research Institute for Nonferrous Metals Beijing100088China China Automotive Battery Research Institute Co.Ltd Beijing101407China

Lithium(Li)metal is the most promising electrode for next-gene ration rechargeable *** order to push the commercialization of the lithium metal batteries,a kind of nitrogen(N)-doped composite graphene(NCG)adopted as the Li plating host was prepared to regulate Li metal nucleation and suppress dendrite ***,a new kind of sandwich-type composite lithium metal(STCL)electrode was developed to improve its *** STCL electrode can be used as convenient as a piece of Li foil but no dendrite *** a symmetric battery,the STCL electrode cycled for more than 4500 h with the overpotential of less than 40 *** due to the creative design,the STCL promises the Li-S battery with a prolonged cycling lifespan.

关键词： Lithium metal anode Lithiophilic N-doped composite graphene Sandwich-type composite lithium metal electrode

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Synergy between CSST galaxy survey and gravitational-wave observation: Inferring the hubble constant from dark standard sirens

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 7-19页

作者： Ji-Yu Song Ling-Feng Wang Yichao Li Ze-Wei zhao Jing-Fei Zhang Wen zhao Xin Zhang Key Laboratory of Cosmology and Astrophysics(Liaoning)&College of Sciences Northeastern UniversityShenyang 110819China CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of Education) Northeastern Universty Shenyang 110819China

Gravitational waves(GWs) from compact binary coalescences encode the absolute luminosity distances of GW sources. Once the redshifts of GW sources are known, one can use the distance-redshift relation to constrain cosmological parameters. One way to obtain the redshifts is to localize GW sources by GW observations and then use galaxy catalogs to determine redshifts from a statistical analysis of redshift information of the potential host galaxies, commonly referred to as the dark siren method. The third-generation(3G) GW detectors are planned to work in the 2030s and will observe numerous compact binary *** these GW events as dark sirens requires high-quality galaxy catalogs from future sky survey projects. The China Space Station Telescope(CSST) will be launched in 2024 and will observe billions of galaxies within a 17500 deg^(2) survey area with redshift up to z ~ 4, providing photometric and spectroscopic galaxy catalogs. In this work, we simulate the CSST galaxy catalogs and the 5-year GW data from the 3G GW detectors and combine them to infer the hubble constant(h_(0)). Our results show that the measurement precision of h0could reach the sub-percent level, meeting the standard of precision cosmology. We conclude that the synergy between CSST and the 3G GW detectors is of great significance in measuring the hubble constant.

关键词： CSST galaxy survey galaxy catalogs gravitational waves dark sirens the hubble constant

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Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

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Rare Metals 2024年第7期43卷 3286-3300页

作者： Wen-Jie zhao Chang-Yu Liu Peng-Cheng Che Zhi-Liang Ning hong-Bo Fan Jian-Fei Sun Yong-Jiang huang Alfonso h.W.Ngan National Key Laboratory for Precision hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China

The distinctive intrinsic heat treatment(IhT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IhT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IhT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IhT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IhT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization heterogeneous grain structure

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Online Pareto optimal control of mean-field stochastic multi-player systems using policy iteration

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Science China(Information Sciences) 2024年第4期67卷 21-37页

作者： Xiushan JIANG Yanshuang WANG Dongya zhao Ling ShI College of New Energy China University of Petroleum(East China) Department of Electronic and Computer Engineering Hong Kong University of Science and Technology

In this study, the Pareto optimal strategy problem was investigated for multi-player mean-field stochastic systems governed by It? differential equations using the reinforcement learning(RL) method.A partially model-free solution for Pareto-optimal control was derived. First, by applying the convexity of cost functions, the Pareto optimal control problem was solved using a weighted-sum optimal control problem. Subsequently, using on-policy RL, we present a novel policy iteration(PI) algorithm based on the hrepresentation technique. In particular, by alternating between the policy evaluation and policy update steps,the Pareto optimal control policy is obtained when no further improvement occurs in system performance,which eliminates directly solving complicated cross-coupled generalized algebraic Riccati equations(GAREs).Practical numerical examples are presented to demonstrate the effectiveness of the proposed algorithm.

关键词： mean-field stochastic systems Pareto optimal control policy iteration scheme $\mathcal{h}$-representation

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Electronic control seed-metering system for precision seeding maize based on fuzzy PID

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 217-226页

作者： Xiaoshun zhao hongpeng zhao Zehe Wang Jincai Li huali Yu Qing Yan State Key Laboratory of North China Crop Improvement and Regulation Hebei Agricultural UniversityBaoding 071001HebeiChina College of Mechanical and Electrical Engineering Hebei Agricultural UniversityBaoding 071001HebeiChina

Aiming at the problem of poor uniformity of maize sowing caused by ground wheel slip,an electronic control seed-metering system(ECSMS)for maize single seed precision sowing was designed and a mathematical model for motor control of the ECSMS was *** PID parameters were set by Z-N method and fuzzy *** fuzzy PID control design and Simulink simulation were completed by MATLAB,which reduced response time of the system by 0.23 s and improved the control *** on the JPS-12 test bench show that the qualification index(QI)of maize seed-metering device with the ECSMS increases by 4.47%,the multiples index(MI)decreases by 1.96%,the miss index(MIX)decreases by 2.81%,and the coefficient of variation(CV)of qualified seed spacing decreases by 5.06%,and the sowing uniformity has been greatly *** results of the soil-tank test bench show that the system has good sowing uniformity and *** the QI is 96.74%,the MI is 2.15%,the MIX is 1.10%,and the CV of qualified seed spacing is 16.24%.Under different setting seed spacing and different sowing operation speed,the change range of seeding quality index was within 10%.The results of field sowing test show that the QI was 84.21%,the MI was 2.63%,the MIX was 7.89%,and the CV of qualified seed spacing was 22.15%,which meet the requirements of JB/T 10293-2013‘Specification for single seed planters(precision planters)’and the agronomic requirements for maize precision *** system runs stably and reliably in practical operation and has good operation performance.

关键词： maize seed-metering system electronic control precision sowing parameters tuning fuzzy PID control simulink simulation

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