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Development of high-power microwave mechanical integrated continuous mining device

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3365-3377页

作者： Xia-Ting Feng Feng Lin Jiuyu Zhang Chengxiang Yang Yuntan ao Tianyang Tong Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology Northeastern UniversityShenyang110819China

This article introduces a high-power microwave mechanical integrated continuous mining device,which can achieve synchronous cutting of hard rocks by microwave and *** device includes a cutting system,a rotary translation system,a loading system,a high-power microwave system,and a control and monitoring *** technology of“master-slave follow-up”disc cutter alternating side cutting of rock was proposed,which could improve the effectiveness of rock *** integrated structure of a microwave-cut system was then proposed,and synchronous motion of the microwave-cut system and adjustment of the loading system could be *** automatic adjustment technology of the microwave working distance was developed to dynamically control the optimal microwave working *** basic functions of the equipment were verified by *** comparing the two types of disk cutters,it is found that the master-slave follow-up disk cutter can improve significantly the dust removal effect and rock breaking efficiency in rock breaking process versus the conventional large disc *** tests of slate with or without microwave were conducted using a master-slave follow-up disk *** results show that the cutting patterns of slates change from intermittent chunks(without microwave irradiation)to persistent debris(with microwave irradiation),and the cutting speed is significantly improved(170%).The development of the device provides a scientific basis for changing the conventional mining technology of metal mines and realizing the mechanical continuous mining in hard metal mines.

关键词： Hard metal mine Microwave machinery Continuous mining Master-slave follow-up disc cutter

Texture and Se vacancy optimization induces high thermoelectric performance in Bi_(2)Se_(3) flexible thin films

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Rare Metals 2024年第6期43卷 2796-2804页

作者： Dong-Wei ao Wei-Di Liu Yue-Xing Chen Fan Ma Yi-Jie Gu Zhuang-Hao Zheng School of Machinery and Automation Weifang UniversityWeifang 261061China Australian Institute for Bioengineering and Nanotechnology The University of QueenslandBrisbane 4072Australia Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China School of Materials Science and Engineering Inner Mongolia University of TechnologyHohhot 010051China

Bi_(2)Se_(3)-based flexible thin film with high thermoelectric performance is promising for the waste heat recovery *** this work,a novel post-selenization method is employed to prepare n-type Bi_(2)Se_(3)flexible thin films with highly textured *** strengthened texture and Se vacancy optimization can be simultaneously achieved by optimizing the selenization *** highly oriented texture leads to the increased carrier mobility and results in a high electric conductivity of~290.47 S·cm^(-1)at 623 ***,a high Seebeck coefficient(>110μW·K-1)is obtained due to the reduced carrier concentration,induced by optimizing vacancy ***,a high power factor of 3.49μW·cm^(-1)·K^(-2)at 623 K has been achieved in asprepared highly-bendable Bi_(2)Se_(3)flexible thin films selenized at 783 *** study introduces an effective post-selenization method to tune the texture structure and vacancies of Bi_(2)Se_(3)flexible thin films,and correspondingly achieves high thermoelectric performance.

关键词： Thermoelectric Bi_(2)Se_(3) Flexible thin film Post-selenization

Lignin‐derived carbon with pyridine N‐B doping and a nanosandwich structure for high and stable lithium storage

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Carbon Energy 2024年第8期6卷 232-247页

作者： Dichao Wu Jiayuan Li Yuying Zhao ao Wang Gaoyue Zhang Jianchun Jiang Mengmeng Fan Kang Sun Key Lab of Biomass Energy and Material Jiangsu ProvinceNational Engineering Lab for Biomass Chemical UtilizationKey and Open Lab on Forest Chemical EngineeringSFAInstitute of Chemical Industry of Forest ProductsChinese Academy of ForestryNanjingChina Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina School of Energy and Environment Southeast UniversityNanjingChina Department of Chemistry Tsinghua UniversityBeijingChina Fujian Provincial Key Laboratory of Biomass Low‐Carbon Conversion Academy of Advanced Carbon Conversion TechnologyHuaqiao UniversityXiamenChina Chinese Academy of Sciences Xinjiang Lihua Institute of Technology UrumqiChina

Biomass‐derived carbon is a promising electrode material in energy storage ***,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a *** this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B *** nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+)diffusion pathway,and accommodating volume expansion during repeated charging/*** abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−)and reduce the diffusion *** BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1)at 0.05 A g^(−1)and superior stability(96.5%retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the *** the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+)and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,***,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+)migration,resulting in good rate ***,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.

关键词： high cycling stability high energy density lithium‐ion batteries pyridinic N‐B species sandwich structure carbon nanosheet

Challenges in applying REE-based thermobarometers: Insights from mafic-ultramafic granulites in Indian southern granulite terrain

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Science China Earth Sciences 2024年第11期67卷 3448-3464页

作者： Xiaofei XU Longlong GOU Chengli ZHANG Junsheng LU Yan ZHao Wenhao ao Yuhua HU Feng ZHOU Faculty of Land Resources Engineering Kunming University of Science and Technology State Key Laboratory of Continental Dynamics Department of Geology Northwest University

High-temperature diffusion of major elements may obscure the records of early and peak metamorphic stages in granulites,while trace elements are more likely to preserve these records due to their lower diffusion ***,using calibrated REE-based thermobarometers has proved essential for reconstructing these key stages,drawing considerable attention and application from ***,the precision of these thermobarometers depends on including both major and trace elements from coexisting minerals to define the correlation coefficients（A,B,and D） among mineral pairs,indicating that the elemental composition of these pairs can affect the *** study examines the mafic-ultramafic granulites in the southern granulite terrain,India,employing integrated methods such as petrography,mineral chemistry,phase equilibrium modeling,and REE-based *** aim to determine their metamorphic conditions and evolutionary history and to identify potential challenges in using REE-based *** garnet,clinopyroxene,and orthopyroxene in the mafic-ultramafic granulite samples display homogeneous compositional profiles,with pronounced Fe-Mg diffusion zones at the interfaces between garnet and ***,the profiles of trace elements within garnet and clinopyroxene are better *** into Fe-Mg exchange and randomly selected mineral pairs significantly influence the accuracy of REE-based ***-Mg exchange can increase in coefficient A,while decreasing coefficient B for light rare earth elements（LREEs） and increasing it for heavy rare earth elements（HREEs）,ultimately resulting in overestimations when calculating REE-based *** example,selecting major compositions with an Ex(=(XMgC-XMg0)/XMg0×100%;where XMgCis the value after Fe-Mg exchange,XMg0is the value before Fe-Mg exchange;XMg=Mg/(Fe2++Mg)) value of ～10 for calculation using the REE-in-Grt-Cpx thermobarometer will result in pressures and t

关键词： Granulites REE-based thermobarometer Fe-Mg exchange Randomly selected mineral pairs

Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research International 2024年第4期31卷 849-860页

作者： Guang-mei Yang Cheng Yuan Chang Liu Qiang Wang Guang-qiang Li Yong-shun Zou ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were *** influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was *** results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based *** TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-Cao complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and ***_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,*** ***_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten *** damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration

The weakening effect of urbanization on tropical cyclone surface winds:An observational study for Shanghai

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Tropical Cyclone Research and Review 2024年第1期13卷 15-23页

作者： Lechuan Zhang Hui Yu Xiangyu ao Shengming Tang Chinese Academy of Meteorological Sciences BeijingChina Shanghai Typhoon Institute China Meteorological AdministrationShanghaiChina

The observation-reanalysis difference method(OMR)and wind proﬁleﬁtting method were used to analyze the inﬂuence urbanization has on the near-surface wind speed in Shanghai during tropical cyclone *** data used include daily wind speed data from the Shanghai Meteorological Observatory Station collected from 1991 to 2020,hourly wind speed data from 100 m high wind towers from 2017 to 2019,and reanalysis data that covered the same *** results indicated that during tropical cyclone occurrence,the wind speed of the OMR in the central urban region was signiﬁcantly lower than that in the suburban area,and the OMR declined more obviously over the year,down to-8 m/s in *** leads to the increase of average wind weakening rate to be higher than the maximum wind weakening rate,causing the maximum weakening rate of the central urban region to the average wind over 80%,while maximum wind speed was less than 80%.The weakening rate of both the average and maximum wind speeds during tropical cyclone impacts is greater than the rate that the annual average wind speed was reduced.A logarithmic variation was visible in the wind proﬁle of the island station during tropical cyclone occurrence,with an average friction velocity U*of 0.9389 m/s and an average rough length Z0 of 0.4915 *** wind speed during tropical cyclone events was higher than the three-year average wind speed within each *** suburban stations show a linear variation,and every hundred meters of height results in an increase of 5–6 m/s in the wind speed change *** 100 m of altitude,the wind speed in the suburban region is reduced by approximately 40%.

关键词： Urbanization Tropical cyclone Shanghai Wind speed

Characteristics of the crack tip field in high-speed railway tunnel linings under train-induced aerodynamic shockwaves

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Underground Space 2024年第5期18卷 199-217页

作者： Yi-Kang Liu Yu-Ling Wang E Deng Yi-Qing Ni Wei-Chao Yang Wai-Kei ao School of Civil Engineering Central South UniversityChangsha 410075China National Rail Transit Electrification and Automation Engineering Technology Research Center(Hong Kong Branch) The Hong Kong Polytechnic UniversityHong Kong 999077China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518057China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China

High-speed railway tunnels in various countries have continuously reported accidents of vault falling concrete *** the concrete block falling occurs,serious consequences follow,and traffic safety may be *** aerodynamic shockwave evolves from the initial compression wave may be an important inducement causing the tunnel lining cracks to grow and form falling concrete blocks.A joint calculation framework is established based on ANSYS Fluent,ABAQUS,and FRANC3D for calculating the crack tip field under the aerodynamic *** intensification effect of aerodynamic shockwaves in the crack is revealed,and the evolution characteristics of the crack tip field and the influence factors of stress intensity factor(SIF)are *** show that(1)the aerodynamic shockwave intensifies after entering the crack,resulting in more significant pressure in the crack than the input *** maximum pressure of the inclined and longitudinal cracks is higher than the corresponding values of the circumferential crack,respectively.(2)The maximum SIF of the circumferential,inclined,and longitudinal crack appears at 0.5,0.68,and 0.78 times the crack front *** maximum SIF of the circumferential crack is higher than that of the inclined and longitudinal *** possibility of crack growth of the circumferential crack is the highest under aerodynamic shockwaves.(3)The influence of train speed on the SIF of the circumferential crack is more than 40%.When the train speed,crack depth,and crack length change,the change of pressure in the crack is the direct cause of the change of SIF.

关键词： Falling concrete blocks Tunnel lining cracks Aerodynamic shockwave Intensification effect Crack tip field Stress intensity factor

Photometric Analysis for Asteroid(81)Terpsichore using Convex Inversion and Phase Function Fitting Methods

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Research in Astronomy and Astrophysics 2024年第6期24卷 201-208页

作者： ao Wang Xiaobin Wang Xiaoyun Xu Longhua Qin Quangui Gao Huaizhen Li Yong Xiao Hairu Zhao Department of Physics Yuxi Normal UniversityYuxi 653100China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China

The shapes and rotation states(periods and pole orientations)of main-belt asteroids are important for understanding their formation and *** order to obtain sufficient photometric data covering different apparitions for asteroid(81)Terpsichore,ground-based photometric observations in 2020 and 2021 were carried *** combining published and newly obtained photometric data,we calculated the shape and spin parameters for(81)Terpsichore using the convex inversion *** this method,we have derived a best fitted pole orientation—(22.2±_(3.1)^(3.3°),17.5±_(5.5)^(10.8°))with a spin period of 10.94±_(0.01)^(0.01)*** on the derived convex shape of(81)Terpsichore,we have fitted the H,G+1,G_(2)phase function using the calibrated TESS data and Gaia data after accounting for the lightcurve amplitude *** a result,we have derived its absolute magnitude H=8.68±_(0.19)^(0.22)mag with corresponding phase function parameters G_(1)=0.82±_(0.10)^(0.09)and G_(2)=0.02±_(0.02)^(0.03).

关键词： asteroids:general minor planets asteroids:individual(Terpsichore) techniques:photometric

Protective effects of baffles with different positions,row spacings,heights on debris flow impact

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Journal of Mountain Science 2024年第7期21卷 2352-2367页

作者： SUN Xinpo CHEN Min BI Yuzhang ZHENG Lu CHE Chi XU ao TIAN Zijian JIANG Zheyuan College of Civil Engineering Sichuan University of Science and EngineeringZigong 643000China College of Resources and Environment Fujian Agriculture and Forestry UniversityFuzhou 350002China School of Civil Engineering Fuzhou UniversityFuzhou 350108China Jiangsu Key Laboratory of Urban Underground Engineering&Environmental Safety Institute of Geotechnical EngineeringSoutheast UniversityNanjing 210096China Beijing Urban Construction Science Technology Promoting Association Beijing 100055China SUSE-BZ Geoenvironmental Engineering Joint Laboratory Sichuan University of Science and EngineeringZigong 643000China

The baffle effectively slowed down debris flow velocity,reduced its kinetic energy,and significantly shortened the distance of debris flow ***,they are widely used for protection against natural hazards such as landslides and *** study,based on the threedimensional DEM(Discrete Element Method),investigated the impact of different baffle positions on debris flow *** flow velocity and kinetic energy variations were studied through single-factor *** baffle positions were preliminarily selected by analyzing the influence of the first-row baffle position on the impact force and accumulation mass of debris ***,based on the selected baffle positions and four factors influencing the effectiveness of baffle protection(baffle position(P),baffle height(h),row spacing(S_(r)),and angle of transit area(α)),an orthogonal design was employed to further explore the optimal arrangement of *** research results indicate that the use of a baffle structure could effectively slow down the motion velocity of debris flows and dissipate their *** the baffle is placed in the transit area,the impact force on the first-row baffle is greater than that when the baffle is placed in the deposition ***,when the baffle is placed in the transit area,the obstruction effect on debris flow mass is also greater than that when the baffle is placed in the deposition *** orthogonal experimental range analysis,when the impact on the first row of baffles is used as the evaluation criterion,the importance of each influencing factor is ranked asα>P>S_(r)>*** the mass of debris flow behind the baffle is regarded as the evaluation criterion,the rank is changed to P>α>S_(r)>*** experimental simulation results show that the optimal baffle arrangement is:P_(5),S_(r)=16,α=35°,h=9.

关键词： Debris flow Baffle Protective effect Discrete element