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Predicting microseismic,acoustic emission and electromagnetic radiation data using neural networks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 616-629页

作者： Yangyang Di Enyuan Wang Zhonghui Li Xiaofei Liu Tao Huang Jiajie Yao School of Materials Engineering Changshu Institute of TechnologySuzhou215506China key laboratory of Gas and Fire Control for Coal Mines(China University of mining and Technology) Ministry of EducationXuzhou221116China School of safety Engineering China University of Mining and TechnologyXuzhou221116China State key laboratory of Coal Resources and Safe mining China University of Mining and TechnologyXuzhou221116China

Microseism,acoustic emission and electromagnetic radiation(M-A-E)data are usually used for predicting rockburst ***,it is a great challenge to realize the prediction of M-A-E *** this study,with the aid of a deep learning algorithm,a new method for the prediction of M-A-E data is *** this method,an M-A-E data prediction model is built based on a variety of neural networks after analyzing numerous M-A-E data,and then the M-A-E data can be *** predicted results are highly correlated with the real data collected in the *** field verification,the deep learning-based prediction method of M-A-E data provides quantitative prediction data for rockburst monitoring.

关键词： Microseism Acoustic emission Electromagnetic radiation Neural networks Deep learning Rockburst

Exceptional points enhance sensing in silicon micromechanical resonators

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Microsystems & Nanoengineering 2024年第1期10卷 17-25页

作者： Man-Na Zhang Lei Dong Li-Feng Wang Qing-An Huang key laboratory of MEMS of the ministry of education Southeast UniversityNanjing 210096China

Exceptional points(EPs)have recently emerged as a new method for engineering the response of open physical systems,that is,systems that interact with the *** systems at the EPs exhibit a strong response to a small ***,we show a method by which the sensitivity of silicon resonant sensors can be enhanced when operated at *** our experiments,we use a pair of mechanically coupled silicon micromechanical resonators constituting a parity-time(PT)-symmetric *** perturbations introduced on the mechanically coupled spring cause the frequency to split from the EPs into the PT-symmetric regime without broadening the two spectrum linewidths,and this frequency splitting scales with the square root of the perturbation *** overall signal-tonoise ratio is still greatly enhanced,although the measured noise spectral density of the EP sensing scheme has a slight increase comparable to the traditional *** results pave the way for resonant sensors with ultrahigh sensitivity.

关键词： resonant symmetric points

Ultrafast micro/nano-manufacturing of metastable materials for energy

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National Science Review 2024年第4期11卷 283-298页

作者： Xiaoya Cui Yanchang Liu Yanan Chen School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education) and Tianjin Key Laboratory of Composite and Functional MaterialsTianjin University ministry of education key laboratory of Protein Sciences School of Life SciencesTsinghua University

The structural engineering of metastable nanomaterials with abundant defects has attracted much attention in energy-related fields. The high-temperature shock(HTS) technique, as a rapidly developing and advanced synthesis strategy, offers significant potential for the rational design and fabrication of high-quality nanocatalysts in an ultrafast, scalable, controllable and eco-friendly way. In this review, we provide an overview of various metastable micro-and nanomaterials synthesized via HTS, including single metallic and bimetallic nanostructures, high entropy alloys, metal compounds(e.g. metal oxides) and carbon nanomaterials. Note that HTS provides a new research dimension for nanostructures, i.e. kinetic modulation. Furthermore, we summarize the application of HTS—as supporting films for transmission electron microscopy grids—in the structural engineering of 2D materials, which is vital for the direct imaging of metastable materials. Finally, we discuss the potential future applications of high-throughput and liquid-phase HTS strategies for non-equilibrium micro/nano-manufacturing beyond energy-related *** is believed that this emerging research field will bring new opportunities to the development of nanoscience and nanotechnology in both fundamental and practical aspects.

关键词： high-temperature shock technique defect engineering metastable phase kinetic modulation non-equilibrium micro/nano-manufacturing

Intermittent disturbance mechanical behavior and fractional deterioration mechanical model of rock under complex true triaxial stress paths

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International Journal of mining Science and Technology 2024年第1期34卷 117-136页

作者： Zhi Zheng Hongyu Xu Kai Zhang Guangliang Feng Qiang Zhang Yufei Zhao State key laboratory of Featured metal Materials and Life-cycle safety for Composite Structures Key Laboratory of Disaster Prevention and Structural Safety of Ministry of EducationCollege of Civil Engineering and ArchitectureGuangxi UniversityNanning 530004China State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China State key laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100080China State key laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

Mechanical excavation,blasting,adjacent rockburst and fracture slip that occur during mining excavation impose dynamic loads on the rock mass,leading to further fracture of damaged surrounding rock in three-dimensional high-stress and even causing ***,a novel complex true triaxial static-dynamic combined loading method reflecting underground excavation damage and then frequent intermittent disturbance failure is *** triaxial static compression and intermittent disturbance tests are carried out on *** effects of intermediate principal stress and amplitude on the strength characteristics,deformation characteristics,failure characteristics,and precursors of monzogabbro are analyzed,intermediate principal stress and amplitude increase monzogabbro strength and tensile fracture *** increases in microseismic parameters during rock loading can be precursors for intermittent rock *** on the experimental result,the new damage fractional elements and method with considering crack initiation stress and crack unstable stress as initiation and acceleration condition of intermittent disturbance irreversible deformation are proposed.A novel three-dimensional disturbance fractional deterioration model considering the intermediate principal stress effect and intermittent disturbance damage effect is established,and the model predicted results align well with the experimental *** sensitivity of stress states and model parameters is further explored,and the intermittent disturbance behaviors at different f are *** study provides valuable theoretical bases for the stability analysis of deep mining engineering under dynamic loads.

关键词： True triaxial static and disturbance test Mechanical properties Failure mechanism and precursor Intermittent disturbance effect Fractional mechanical model

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao GUO Peifeng GAO Xingzhe WANG key laboratory of Mechanics on Western Disaster and Environment of ministry of education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting *** respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic *** numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally ***,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake *** approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic *** then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic *** results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and *** proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine

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China Ocean Engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU Wan-li WANG Pi-guang QU Yang DU Xiu-li key laboratory of Urban Security and Disaster Engineering of ministry of education Beijing University of TechnologyBeijing 100124China State key laboratory of Bridge Engineering safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field

Electroacupuncture ameliorates blood-brain barrier disruption after ischemic stroke through histone acetylation regulation at the matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 2 genes

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Journal of Traditional Chinese Medicine 2024年第4期44卷 734-744页

作者： CHEN Yonglin OUYANG Ling MENG Lingling WU Bufan PENG Rou LIU Sitong HOU Dan WANG Yaling JING Xinyue LU Shengfeng FU Shuping key laboratory of Acupuncture and Medicine Research of ministry of education Nanjing University of Chinese Medicine

OBJECTIVE: To explore whether the regulation of matrix metalloproteinase 9(MMP-9)/tissue inhibitors of MMPs(TIMPs) gene expression through histone acetylation is a possible mechanism by which electroacupuncture(EA)protects blood-brain barrier(BBB) integrity in a middle cerebral artery occlusion(MCAO) rat ***: Male Sprague-Dawley rats were divided into four groups: the sham group, the MCAO group, the MCAO + EA(MEA) group, and the MCAO + EA + HAT inhibitor(HATi) group. The MCAO model was generated by blocking the middle cerebral artery. EA was applied to Baihui(GV20). Samples were collected 1 or 3 d after reperfusion. Neurological function scores and Evans blue extravasation were employed to evaluate the poststroke injury. The effect of EA on MMP-9/TIMPs gene expression was assessed by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR) and chromatin immunoprecipitation(ChIP). RESULTS: Our results showed that EA treatment prominently improved neurological function and ameliorated BBB disruption. The RT-qPCR assay showed that EA reduced the expression of MMP-9 and promoted TIMP-2 mRNA expression, but HATi reversed these effects of EA. In addition, ChIP results revealed that EA decreased the enrichment of H3K9ace/H3K27ace at MMP-9 promoters and notably stimulated the recruitment of H3K9ace/H3K27ace at TIMP-2 promoter. CONCLUSION: EA treatment at Baihui(GV20) regulates the transcription of MMP-9 and TIMP-2 through histone acetylation modification in the acute stage of stroke, which preserves the structural integrity of the BBB in MCAO rats. These findings suggested that the histone acetylation-mediated transcriptional activity of target genes may be a crucial mechanism of EA treatment in stroke.

关键词： blood-brain barrier electroacupuncture histone acetylation matrix metalloproteinase 9 tissue inhibitor of metalloproteinases

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Economic analysis of rooftop photovoltaics system under different shadowing conditions for 20 cities in China

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Building Simulation 2024年第2期17卷 235-252页

作者： Zhiyi Ren Yixing Chen Chengcheng Song Mengyue Liu Anni XuQilin Zhang College of Civil Engineering Hunan UniversityChangsha410082China key laboratory of Building safety and Energy Efficiency of ministry of education Hunan UniversityChangsha410082China

Installing photovoltaic(PV)systems is an essential step for low-carbon *** economics of PV systems are strongly impacted by the electricity price and the shadowing effect from neighboring *** study evaluates the PV generation potential and economics of 20 cities in China under three shadowing ***,the building geometry models under three shadowing conditions for the 20 cities were constructed using ***,60 building models with PV systems and shadows from surrounding buildings were generated by City Buildings,Energy,and Sustainability(CityBES),an open platform,to simulate the PV power ***,the study presented one economic analysis model to evaluate the profitability by combining the market cost of rooftop PV systems and electricity prices in *** economic model included four indicators:payback period(static and dynamic),net present value(NPV),and internal rate of return(IRR).The results show that the reduction of PV power generation ranges from 8.29%to 16.01%under medium shadowing,and experiences a maximum decrease of up to 39.71%under high *** economic analysis shows that almost all the regions show reliable potential,obtaining an IRR higher than the reference value(5%).Nenjiang has the highest economic profit,with the highest NPV(86,181.15 RMB)and IRR(30.14%)under no shadowing among 20 *** also should be mentioned that the alignment between electricity price distribution and the solar power generation curve will directly impact the economic potential of PV systems.

关键词： rooftop photovoltaic system EnergyPlus economic analysis shadowing buildings electric price

Laser-upgraded coal tar for smart pavements in road and bridge monitoring applications

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Microsystems & Nanoengineering 2024年第2期10卷 231-239页

作者： Jincai Huang Man Zhang Haoyun He Qingang Li Yixin Zhao Qiulin Tan Xining Zang Department of Mechanical Engineering Tsinghua UniversityBeijing100084China State key laboratory of Clean and efficient Turbomachinery Power Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing100084China key laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing100084China Science and Technology on Electronic Test and Measurement laboratory North University of ChinaTaiyuan030051China School of Energy and mining Engineering China University of Mining and Technology(Beijing)Beijing100083China

The implementation of an intelligent road network system requires many sensors for acquiring data from roads,bridges,and vehicles,thereby enabling comprehensive monitoring and regulation of road *** this large number of required sensors,the sensors must be cost-effective,dependable,and environmentally ***,we show a laser upgrading strategy for coal tar,a low-value byproduct of coal distillation,to manufacture flexible strain-gauge sensors with maximum gauge factors of 15.20 and 254.17 for tension and compression ***,we completely designed the supporting processes of sensor placement,data acquisition,processing,wireless communication,and information decoding to demonstrate the application of our sensors in traffic and bridge vibration *** novel strategy of using lasers to upgrade coal tar for use as a sensor not only achieves the goal of turning waste into a resource but also provides an approach to satisfy large-scale application requirements for enabling intelligent road networks.

关键词： gauge bridge smart