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Dynamic characteristics of coal specimens with varying static preloading levels under low-frequency disturbance load

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Journal of Central South University 2024年第8期31卷 2644-2657页

作者： WEN Xiao-ze feng guo-rui guo Jun YU Lu-yang QIAN rui-peng ZHANG Jie ZHANG Peng-fei feng Wen-ming College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Hydroelectric and Engineering Tsinghua UniversityBeijing 100084China

The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working *** study conducted low-frequency disturbance dynamic uniaxial compression tests on coal specimens using a self-developed dynamic-static load coupling electro-hydraulic servo system,and studied the strength evolutions,surface deformations,acoustic emission(AE)characteristic parameters,and the failure modes of coal specimens with different static preloading levels were *** disturbance damage is positively correlated with the coal specimen static preload ***,the cumulative AE count rates of the initial accelerated damage stage for the coal specimens with static preloading level of 60%and 70%of the uniaxial compressive strength(UCS)were 2.66 and 3.19 times that of the 50%UCS specimens,***,this behaviour manifested as a decrease in the compressive strength,and the mean strengths of the disturbance-damaged coal specimens with 60%and 70%of UCS static preloading decreased by 8.53%and 9.32%,respectively,compared to those of the specimens under pure static *** crack sources,such as the primary fissures,strongly control the dynamic response of the coal *** difference between the dynamic responses of the coal specimens and that of dense rocks is significant.

关键词： low-frequency disturbance dynamic response coal specimens static preloading level

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酸性矿井水环境中矸石胶结充填体的强度演化及劣化规律

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Journal of Central South University 2024年第5期31卷 1560-1573页

作者：赵永辉郭育霞冯国瑞 College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Shanxi Province Research Centre of Green Mining Engineering Technology Taiyuan 030024China Shanxi Province Coal-based Resources Green and High-efficiency Development Engineering Center Taiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024China

矸石胶结充填开采是一种重要的充填开采方法,然而,酸性矿井水会严重影响矸石胶结充填体的强度。在本研究中,将矸石胶结充填体试件分别置于不同环境(空气、水、硫酸溶液、硫酸与荷载耦合)中,测试了不同龄期试件的抗压强度、电阻率及超声... 详细信息

矸石胶结充填开采是一种重要的充填开采方法,然而,酸性矿井水会严重影响矸石胶结充填体的强度。在本研究中,将矸石胶结充填体试件分别置于不同环境(空气、水、硫酸溶液、硫酸与荷载耦合)中,测试了不同龄期试件的抗压强度、电阻率及超声波波速,监测了加载过程中试件的声发射能量数值,同时结合扫描电镜和X衍射分析不同龄期充填体的微观结构。结果表明,1)空气中与水中养护的充填体抗压强度的增长趋势随龄期的增加而逐渐减缓。硫酸溶液中的充填体强度在前90天大于空气及水中养护的充填体强度。硫酸溶液与荷载耦合作用下充填体的强度随龄期的下降速率比单一硫酸溶液作用的较为缓慢;2)不同龄期矸石胶结充填体电阻率与超声波波速与强度有较好的对应关系。受侵蚀后矸石胶结充填体的破坏形式较为多样,且在加载不同阶段表现出不同的声发射能量特征,可以将声发射能量激增作为充填体的破坏前兆;3)侵蚀产物前期填充充填体内部孔隙,提高了其强度,后期会导致充填体膨胀开裂,强度降低。施加40%应力强度比的荷载会抵抗硫酸溶液的侵蚀。本文研究结果可以为充填体的耐侵蚀设计提供参考。

关键词：酸性矿井水矸石胶结充填体劣化规律电阻率超声波波速声发射能量微观结构

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Failure mechanisms and destruction characteristics of cemented coal gangue backfill under compression effect of non-uniform load

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Journal of Central South University 2024年第8期31卷 2676-2693页

作者： feng guo-rui guo Wei QI Ting-ye LI Zhu CUI Jia-qing WANG Hao-chen CUI Ye-kai MA Jing-kai College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Shanxi Province Research Center of Green Mining Engineering Technology Taiyuan 030024China Shanxi Province Coal-based Resources Green and High-efficiency Development Engineering Center Taiyuan 030024China Shanxi Key Laboratory of Mine Rock Strata Control and Disaster Prevention Taiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024China

Backfill mining is one of the most important technical means for controlling strata movement and reducing surface subsidence and environmental damage during exploitation of underground coal resources. Ensuring the stability of the backfill bodies is the primary prerequisite for maintaining the safety of the backfilling working face, and the loading characteristics of backfill are closely related to the deformation and subsidence of the roof. Elastic thin plate model was used to explore the non-uniform subsidence law of the roof, and then the non-uniform distribution characteristics of backfill bodies’ load were revealed. Through a self-developed non-uniform loading device combined with acoustic emission (AE) and digital image correlation (DIC) monitoring technology, the synergistic dynamic evolution law of the bearing capacity, apparent crack, and internal fracture of cemented coal gangue backfills (CCGBs) under loads with different degrees of non-uniformity was deeply explored. The results showed that: 1) The uniaxial compressive strength (UCS) of CCGB increased and then decreased with an increase in the degree of non-uniformity of load (DNL). About 40% of DNL was the inflection point of DNL-UCS curve and when DNL exceeded 40%, the strength decreased in a cliff-like manner;2) A positive correlation was observed between the AE ringing count and UCS during the loading process of the specimen, which was manifested by a higher AE ringing count of the high-strength specimen. 3) Shear cracks gradually increased and failure mode of specimens gradually changed from “X” type dominated by tension cracks to inverted “Y” type dominated by shear cracks with an increase in DNL, and the crack opening displacement at the peak stress decreased and then increased. The crack opening displacement at 40% of the DNL was the smallest. This was consistent with the judgment of crack size based on the AE b-value, i. e., it showed the typical characteristics of “small b-value-large crack and

关键词： cemented coal gangue backfill non-uniform load degree of non-uniformity of load failure mode crack opening displacement

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Compressive performance of innovative reinforced pillars in closed/abandoned mines

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Journal of Central South University 2024年第8期31卷 2780-2793页

作者： LI Jian BAI Jin-wen feng guo-rui WANG Shan-yong ZHAO Hong-chao MI Jia-chen PAN rui-kai SHI Xu-dong MA Jun-biao College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan University of TechnologyTaiyuan 030024China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024China Department of Mining Engineering Shanxi Institute of EnergyJinzhong 030600China Priority Research Centre for Geotechnical Science and Engineering School of Engineeringthe University of NewcastleCallaghanNSW 2308Australia School of Geology and Mining Engineering Xinjiang UniversityUrumqi 830000China

Pillar is closely related to the stability and reliability of underground spaces in closed/abandoned *** present research introduced a new technique to strengthen square cement mortar columns via fiber-reinforced polymer(FRP)strips to verify the strengthening effect of FRP on *** to a fully wrapped FRP jacket,the advantages of FRP strip are cost-effective and easy-to-construct.A series of compression tests as well as theoretical analysis were carried out to explore the mechanical behavior of square cement mortar specimens partially strengthened with FRP *** results verified the effectiveness of FRP strips in enhancing the stress and strain of cement *** from unconfined cement mortar specimens,these FRP-strengthened cement mortar specimens are featured with the double-peaked behaviors,mainly attributed to the stress state transformation from a one-dimensional to a three-dimensional stress *** also indicated that the enhancement of stress increased with the FRP strip ***,the brittle-ductile transition ductile failure characteristics were also observed in FRP-confined cement mortar *** ultimate ductility of the cement mortar specimen decreases gradually with the growth of the FRP strip *** main contribution of this research is to enrich the strengthening techniques for residual pillars.

关键词： fiber-reinforced polymer uniaxial compression partially strengthening double-peaked behaviors brittle-ductile transition

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Study on “triangle” water-inrush mode of strong water-guide collapse column

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Journal of Central South University 2016年第9期23卷 2402-2409页

作者： LI Zhen-hua feng guo-rui ZHAI Chang-zhi School of Energy Science ＆ Engineering Henan Polytechnic University Jiaozuo 454000 China College of Mining Technology Taiyuan University of Technology Taiyuan 030024 China

The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological background of Shuangliu mine is considered a prototype, similar simulation tests are adopted to analyze the water-inrush rules under this model, and the formation of water-guide channel and water-inrush process is investigated by examining the changes in rock resistivity. This work also uses the coupled cloud image derived from numerical simulation software to verify the results of simulation test. Results show that the numerical simulation of "triangle" water-inrush mode is consistent with the similar simulation. The "triangle" seepage area, which is located at the bottom of collapse columns and is connected to aquifer, is caused by the altered seepage direction and strengthened seepage actions after the overlapping of hydraulic transverse seepage in collapse column and hydraulic vertical seepage flow in aquifer. Under "triangle"water-inrush model, water-guide channel is formed by the communication between plastic failure zone of working face baseplate and"triangular" seepage area. Accordingly, the threatening water-inrush distance between working face and collapse column increases by 20 m compared with that of theoretical calculation.

关键词： strong water-guide collapse column "triangle" water-inrush mode similar simulation numerical simulation seepage

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Synthesis and characterization of novel polypropylene paper releasing anion

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Chinese Chemical Letters 2009年第4期20卷 483-486页

作者： Li Qiu Wang Qing Shan Li Hui Peng Ma Xiao feng guo rui Hong Wang Gang Yao College of Environmental and Chemical Engineering State Key Laboratory of Metastable Materials Science and Technology Yanshan University State Key Laboratory of Metastable Materials Science and Technology Qinhuangdao 066004 China

Polypropylene synthetic paper releasing anion was prepared from polypropylene resin, anion additives, titanium dioxide, etc., by calendar forming method. The synthetic paper was tested by anion detector, SEM, AFM, etc. Tensile strength, elongation at break, fight angle tear strength of the polypropylene synthetic paper reached the GB 13022 or QB/T1130 Standard. The synthetic paper was water and oil resistance, and released anions 10,530 cm^-3. It was environment-friendly, and a kind of good material for human＇s health.

关键词： Synthetic paper Polypropylene Functional polymer Health material Anions releasing

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A Sparse Representation Algorithm for the Mode Separation and SNR Improvement of Lamb Wave Signals

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Chinese Physics Letters 2013年第3期30卷 96-99页

作者： YU Yong-Ling ZHANG Hai-Yan SHI Fang-Fang feng guo-rui MA Shi-Wei School of Communication and Information Engineering Key Laboratory of Specialty Fiber Optics and Optical Access NetworksShanghai UniversityShanghai 200072 Institute of Acoustics Chinese Academy of SciencesBeijing 100080 Shanghai Key Laboratory of Power Station Automation Technology School of Mechatronic Engineering and AutomationShanghai UniversityShanghai 200072

A matching pursuit method based on training an over-complete dictionary is *** using the K-singular value decomposition(K-SVD)algorithm,an over-complete dictionary that describes the Lamb wave signals is *** results demonstrate that the method can effectively remove redundant information and separate multiple Lamb wave *** matching pursuit method with the K-SVD algorithm shows its efficiency for Lamb wave signal processing.

关键词： matching pursuit wave

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Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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Defence Technology（防务技术） 2024年第4期34卷 217-224页

作者： rui Zhao Jian Zheng Jin guo Yunbo Shi Hengzhen feng Jun Tang Jun Liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss

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The role of strain in oxygen evolution reaction

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Journal of Energy Chemistry 2024年第6期93卷 322-344,I0009页

作者： Zihang feng Chuanlin Dai Zhe Zhang Xuefei Lei Wenning Mu rui guo Xuanwen Liu Junhua You School of Materials Science and Engineering Northeastern UniversityShenyang 110819LiaoningChina School of Materials Science and Technology Shenyang University of TechnologyShenyang 110870LiaoningChina

The oxygen evolution reaction(OER)is a crucial step in metal-air batteries and water splitting technologies,playing a significant role in the efficiency and achievable heights of these two ***,the OER is a four-step,four-electron reaction,and its slow kinetics result in high overpotentials,posing a *** address this issue,numerous strategies involving modified catalysts have been proposed and proven to be highly *** these strategies,the introduction of strain has been widely reported because it is generally believed to effectively regulate the electronic structure of metal sites and alter the adsorption energy of catalyst surfaces with reaction ***,strain has many other effects that are not well known,making it an important yet unexplored *** on this,this review provides a detailed introduction to the various roles of strain in *** better explain these roles,the review also presents the definition of strain and elucidates the potential mechanisms of strain in OER based on the d-band center theory and adsorption volcano ***,the review showcases various ways of introducing strain in OER through examples reported in the latest literature,aiming to provide a comprehensive perspective for the development of strain ***,the review analyzes the appropriate proportion of strain introduction,compares compressive and tensile strain,and examines the impact of strain on *** the review offers prospects for future research directions in this emerging field.

关键词： Oxygen evolution reaction Strain generation Tensile strain Compressive strain Strain mechanism Strain effects

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Plasma-assisted ammonia synthesis under mild conditions for hydrogen and electricity storage:Mechanisms,pathways,and application prospects

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Frontiers in Energy 2024年第4期18卷 418-435页

作者： feng GONG Yuhang JING rui XIAO Key Laboratory of Energy Thermal Conversion and Process Measurement and Control of the Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China

Ammonia,with its high hydrogen storage density of 17.7 wt.%(mass fraction),cleanliness,efficiency,and renewability,presents itself as a promising zero-carbon ***,the traditional Haber−Bosch(H−B)process for ammonia synthesis necessitates high temperature and pressure,resulting in over 420 million tons of carbon dioxide emissions annually,and relies on fossil fuel *** contrast,dielectric barrier discharge(DBD)plasma-assisted ammonia synthesis operates at low temperatures and atmospheric pressures,utilizing nitrogen and hydrogen radicals excited by energetic electrons,offering a potential alternative to the H−B *** method can be effectively coupled with renewable energy sources(such as solar and wind)for environmentally friendly,distributed,and efficient ammonia *** review delves into a comprehensive analysis of the low-temperature DBD plasma-assisted ammonia synthesis technology at atmospheric pressure,covering the reaction pathway,mechanism,and catalyst system involved in plasma nitrogen *** from current research,it evaluates the economic feasibility of the DBD plasmaassisted ammonia synthesis technology,analyzes existing dilemmas and challenges,and provides insights and recommendations for the future of nonthermal plasma ammonia processes.

关键词： plasma catalysis nitrogen fixation ammonia synthesis hydrogen storage catalyst carbon neutralization

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