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Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1799-1815页

作者： Kaizong Xia Zhiwei Si Congxin Chen Xiaoshuang li Junpeng zou Jiahao Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Urban Construction Changzhou UniversityChangzhou 213164China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical ***,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium *** results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition ***,failure first occurs in certain superimposed strata slightly far from the ***,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the *** process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the *** deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping *** effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than *** strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling ***,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever *** taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the ke

关键词： sublevel caving mines universal distinct element code(UDEC)numerical approach large-scale ground movement steeply dipping superimposed cantilever beam toppling failure

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Boosted sustained-release with iron-based MOF-derived mesoporouscarbon-spheres as a nitroimidazole drugs carrier

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Particuology 2024年第3期86卷 269-280页

作者： Danping Wu Jiaying zou Junyi Chen Yan li Na Ma Wei Dai College of Chemistry and Materials Science Zhejiang Normal UniversityJinhua321004China College of life Sciences Zhejiang Normal UniversityJinhua321004China College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua321004China

Metal-organic framework(MoF)with a buildable internal structure has aroused great interest focus as self-sacrificing precursors of porous carbon(PC).However,as a drug carrier,the MOF-derived PC developed thus far are generally composed of irregular powder shape due to their crystalline nature,which consequently causing the cerebral infarction,cerebral thrombosis,and other blood *** this article,we propose a novel approach to constructing amorphous carbon microspheres(AcMs)by dis-torting the topological network through hydrothermal treatment precursors of MIL-101(Fe).Then,a distinctive MIL-101(Fe)-derived spherical porous carbons(MSPC)is achieved through high temperature calcination toward *** of the glucose initial concentration and hydrothermal treatment time on the sphericity of the as-prepared mesoporous MsPC were investigated in *** the loading capacities and sustained-release performances of nitroimidazole drugs over MsPC through simulation internal environment of human body at different pH values was systematically *** nitro-imidazole drugs loading rate and release time of MsPC are 10% and 17 h under preferred ***,the MSPC exhibited very low toxicity on Hela cells and 293T cells at the concentrations tested(10-800μg mL^(-1)).This study,therefore,supports the potential of the mesoporous carbon spheres as a carrierfor nitroimidazole drug delivery.

关键词： Ornidazole Metronidazole Carbon spheres Sustained-release performance Biocompatibility

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Grain size and surface micro-texture characteristics and their paleoenvironmental significance of Holocene sediment in southern margin of the Gurbantunggut Desert,China

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Journal of Arid Land 2024年第5期16卷 632-653页

作者： MA Yunqiang li Zhizhong TAN Dianjia zou Xiaojun TAO Tonglian School of Geographical Sciences Fujian Normal UniversityFuzhou 350117China Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350117China Institute of Geography Fujian Normal UniversityFuzhou 350117China

The southern margin of the Gurbantunggut Desert,China,is characterized by alternating layers of aeolian and alluvial *** the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces,as well as the provenance of ***,there are relatively few investigations on the characteristics of such sediment at *** this study,we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut *** on the optically stimulated luminescence(OSL)dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture,we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene,as well as the provenance of *** results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand,interdune sand,muddy desert surface soil,and riverbed *** frequency curves were unimodal or bimodal,and cumulative probability curves were two-segment or three-segment,mainly composed of suspension load and saltation *** quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces,with short transportation distance and time,and sedimentary environment was relatively *** Holocene,southern margin of the desert primarily featured braided river deposits,and during intermittent period of river activity,there were also aeolian deposits such as sand sheet deposits,stabilized dune deposits,and mobile dune *** provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant,with the debris of the Tianshan Mountains being the primary *** sand is mainly near-source recharge,

关键词： aeolian-alluvial deposition grain size surface micro-texture sedimentary environment Holocene

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Effect of(Cr,V)_(2)(C,N)on the Microstructure and Mechanical Properties of WC-10Co Cemented Carbides

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1138-1148页

作者： li Xiangkun WANG Lu ye Jinwen School of Materials Science and Engineering Sichuan UniversityChengdu 610065China

WC-10Co cemented carbides with finer WC and narrower grain size distributions are produced by using(Cr,V)_(2)(C,N)as grain growth *** a result,with the increase of(Cr_(0.9),V_(0.1))_(2)(C,N)and(V_(0.9),Cr_(0.1))_(2)(C,N),the grains size of WC and mean free path of Co phase decrease,and adjacency of WC *** and homogenization of grains enhance the transverse rupture strength(TRS)and the ***,the deflection and bridging of cracks keep the fracture toughness at a respectable *** WC-10Co-0.6(Cr_(0.9),V_(0.1))_(2)(C,N)-0.025(V_(0.9),Cr_(0.1))_(2)(C,N)cemented carbides exhibit excellent comprehensive mechanical properties with the TRS of 4602.6 MPa,hardness of 1835 kg/mm^(2),and fracture toughness of 10.39 MPa·m^(1/2),***,the large pores are caused by excess N larger than 0.03 wt%and deteriorates the mechanical *** provide a new approach to WC-Co cemented carbides preparation with a narrow grain size distribution by adding novel grain growth inhibitors.

关键词： (Cr,V)_(2)(C,N) nutrient content WC grains size microstructure mechanical properties

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Structural disruption of melanin-like polymers with boosted UV protection

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Science China Chemistry 2024年第5期67卷 1653-1663页

作者： Zhen Yang Xianheng Wang Wanjie Bai Zikun zou Haoxing Wu Yiwen li Department of Radiology Huaxi MR Research CenterFunctional and Molecular Imaging Key Laboratory of Sichuan ProvinceNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengdu 610041China College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Manipulating the energy structure of materials represents an efficient way to regulate their light absorption behaviors. For example, constructing donor-acceptor(D-A) structures to increase the polarizability and reduce the energy bandgap of local molecules has been widely used in the field of organic photovoltaics with ordered structures. Remarkably, even in disordered and chaotic systems such as melanin-like polydopamine(PDA), visible and near-infrared light absorption can be significantly improved using this strategy. However, there has been a noticeable dearth of research on the ultraviolet(UV) light absorption regulation of bioinspired polymers with disordered and chaotic architectures by tailoring the D-A microstructures. In this study, a series of benzoheterocyclic molecules with strong electron-donating features screened by molecular simulation calculations were involved in disrupting the D-A structures within PDA. The destruction of D-A structures promoted the increase of the energy band gap and finally boosted the UV absorption of PDA. The resulting PDA nanoparticles with enhanced UV absorption were further employed to fabricate UV shielding composite films to protect the growth of plants from harmful UV radiation. This research may open up new avenues for structural disruption of bioinspired polymers for enhanced photoprotection applications.

关键词： melanin-like polymers polydopamine D-A structure UV absorption photoprotection

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SAM3D: zero-shot 3D object detection via the segment anything model

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Science China(Information Sciences) 2024年第4期67卷 331-332页

作者： Dingyuan ZHANG Dingkang liANG Hongcheng YANG Zhikang zou Xiaoqing ye Zhe liU Xiang BAI School of Artificial Intelligence and Automation Huazhong University of Science and Technology Baidu Inc. School of Electronic Information and Communication Huazhong University of Science and Technology

In the past few years, foundation models have thrived and succeeded in linguistic and visual tasks, showing astonishing zero-shot and few-shot capabilities. Their advances encourage researchers and industries to extend the boundaries of what artificial intelligence can do and have shown some fantastic products(e.g., ChatGPT [1]) with the potential to change the world.

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Deep Video Harmonization by Improving Spatial-temporal Consistency

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Machine Intelligence Research 2024年第1期21卷 46-54页

作者： Xiuwen Chen li Fang Long ye Qin Zhang Key Laboratory of Media Audio and Video Ministry of Education Communication University of ChinaBeijing 100024China

Video harmonization is an important step in video editing to achieve visual consistency by adjusting foreground appear-ances in both spatial and temporal *** methods always only harmonize on a single scale or ignore the inaccuracy of flow estimation,which leads to limited harmonization *** this work,we propose a novel architecture for video harmoniza-tion by making full use of spatiotemporal features and yield temporally consistent harmonized *** introduce multiscale harmon-ization by using nonlocal similarity on each scale to make the foreground more consistent with the *** also propose a fore-ground temporal aggregator to dynamically aggregate neighboring frames at the feature level to alleviate the effect of inaccurate estim-ated flow and ensure temporal *** experimental results demonstrate the superiority of our method over other state-of-the-art methods in both quantitative and visual comparisons.

关键词： Harmonization temporal consistency video editing video composition nonlocal similarity

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Impacts of Water-Sediment Regulation Scheme on Chromophoric Dissolved Organic Matter in the Lower yellow River

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Journal of Ocean University of China 2024年第2期23卷 455-466页

作者： liU Xiao JIANG Xueyan liU Qian SUI Juanjuan zou li Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education Ocean University of ChinaQingdao 266100China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China School of Earth Sciences University of BristolBristolBS81RJUK North China Sea Environmental Monitoring Center State Oceanic AdministrationQingdao 266033China Key Laboratory of Ecological Prewarning Protection and Restoration of Bohai SeaMinistry of Natural ResourcesQingdao 266033China Key Laboratory of Marine Environment and Ecology of Ministry of Education Ocean University of ChinaQingdao 266100China College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China

As a river with more than 3000 reservoirs in its watershed,the yellow River has been affected by dams not only on the sediment load,but also on the water ***-sediment regulation scheme(WSRS),which has been carried out annually in the yellow River since 2002,is a typical human activity affecting river water *** dissolved organic matter(CDOM)in river is susceptible to changes in ecological and environmental conditions as well as human ***,we report variations in dissolved organic carbon concentrations,compositions and sources of CDOM in time series samples in the lower yellow River during *** addition,a parallel factor fluorescence analysis(PARAFAC)method is applied to identify different fluorescent components in water samples during WRSR,showing four major components including tryptophan-like component(C1),microbial humic-like component(C2),terrestrial humic-like component(C3)and tyrosine-like component(C4).In general,C1 increased after water regulation,while C2 and C3 increased after sediment regulation,indicating that the water and sediment released by the dam have different effects on CDOM *** the impacts of the dam,source of CDOM in the lower yellow River is mainly autochthonous related to microbial activities,and is regulated by the terrestrial input during WSRS *** resuspension inhibits microbial activities and reduces the production of autochthonous ***,human activities especially WSRS,as exemplified here,significantly alter the quality and quantity of CDOM in the lower yellow River,affecting CDOM dynamics and biogeochemical processes in the estuarine environment.

关键词： chromophoric dissolved organic matter(CDOM) water-sediment regulation scheme(WSRS) yellow River optical properties

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Extrusion-base d 3D-printe d“rolle d-up”composite scaffolds with hierarchical pore structure for bone growth and repair

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Journal of Materials Science & Technology 2024年第4期171卷 222-234页

作者： Yufan li li Chen Yijing Stehle Mingyue lin Chenxin Wang Rui Zhang Min Huang Yubao li Qin zou Research Center for Nano Biomaterials Analytical&Testing CenterSichuan UniversityChengdu 610064China Analytical&Testing Center Sichuan UniversityChengdu 610064China Department of mechanical engineering Union College807 Union St.SchenectadyNY 12308USA Sichuan Institute of Atomic Energy Chengdu 610101China

Three-dimensional(3D)bioprinting,specifically direct ink writing(DIW)capable of printing biologically active substances such as growth factors or drugs under low-temperature conditions,is an emerging di-rection in bone tissue ***,limited by the bio-ink mobility and the poor resolution of this printing technology,the lateral pores of current crisscross-stacked scaffolds printed through DIW tend to clog and are inimical to bone ***,it is critical to develop DIW printed biologi-cal scaffold structure with high mechanical strength,porosity,and biocompatibility ***,patterned polylactic acid(PLA)/polycaprolactone(PCL)/nano-hydroxyapatite(n-HA)based scaffold was printed through DIW technological and rolled-up for properties characterization,cytocompatibility test,and bone repair *** result not only shows that the hexagonal patterned scaffolds are me-chanically strong with porosity,but also demonstrated that the hierarchical pore structure formed during rolled-up has the potential to address the clogging problem and stimulates bone growth and repair.

关键词： Direct ink writing(DIW) Bone repair scaffold,Micro-CT Bio composites

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A novel high-Cr CoNi-based superalloy with superior high-temperature microstructural stability, oxidation resistance and mechanical properties

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1373-1381页

作者： Xiaorui Zhang Min zou Song Lu Longfei li Xiaoli Zhuang Qiang Feng Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced MetalsUniversity of Science and Technology BeijingBeijing 100083China

A novel multicomponent high-Cr CoNi-based superalloy with superior comprehensive performance was prepared,and the evaluation of its high-temperature microstructural stability,oxidation resistance,and mechanical properties was conducted mainly using its cast polycrystalline *** results disclosed that the morphology of theγ′phase remained stable,and the coarsening rate was slow during the long-term aging at 900–1000℃.The activation energy forγ′precipitate coarsening of alloy 9CoNi-Cr was(402±51)kJ/mol,which is higher compared with those of CMSX-4 and some other Ni-based and Co-based ***,there was no indica-tion of the formation of topologically close-packed phases during this *** these factors demonstrated the superior microstructural stability of the *** mass gain of alloy 9CoNi-Cr was 0.6 mg/cm^(2) after oxidation at 1000℃ for 100 h,and the oxidation resistance was comparable to advanced Ni-based superalloys CMSX-4,which can be attributed to the formation of a continuous Al_(2)O_(3) protective ***,the compressive yield strength of this cast polycrystalline alloy at high temperatures is clearly higher than that of the conventional Ni-based cast superalloy and the compressive minimum creep rate at 950℃ is comparable to that of the conventional Ni-based cast superalloy,demonstrating the alloy’s good mechanical properties at high *** is partially because high Cr is bene-ficial in improving theγandγ′phase strengths of alloy 9CoNi-Cr.

关键词： CoNi-based superalloys microstructure coarsening oxidation mechanical properties

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