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Volume-averaged modeling of multiphase solidification with equiaxed crystal sedimentation in a steel ingot

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China Foundry 2024年第3期21卷 229-238页

作者： Xiao-lei Zhu Shuang cao Rui Guan Ji Yang Zhe Ning Xin-gang ai Sheng-li li Xin-cheng Miao The key Laboratory of Material Forming and Structure Property Control Anshan 114051LiaoningChina State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009LiaoningChina School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

Macrosegregation is a critical factor that limits the mechanical properties of *** impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a *** improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian *** this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered *** sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the ***,noticeable positive macrosegregation occurs in the area of final solidification in the *** improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting *** mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.

关键词： ingot casting multiphase solidification model equiaxed crystal sedimentation microstructure macrosegregation

Synergistic effects of Pleistocene geological and climatic events on complex phylogeographic history of widespread sympatric species of Megaloptera in East Asia

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Zoological Research 2024年第5期45卷 1131-1146页

作者： ai-li lin Ming-Ming Zou li-Jun cao Fumio Hayashi Ding Yang Xing-Yue liu Department of Entomology China Agricultural UniversityBeijing 100193China Sanya Institute of China Agricultural University SanyaHainan 572025China International Joint Laboratory of Taxonomy and Systematic Evolution of Insecta Henan Institute of Science and TechnologyXinxiangHenan 453003China Institute of Plant and Environmental Protection Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China Department of Biology Tokyo Metropolitan UniversityHachioji-shiTokyo 192-0397Japan

Unraveling the phylogeographic histories of species remains a key endeavor for comprehending the evolutionary processes contributing to the rich biodiversity and high endemism found in East *** this study,we explored the phylogeographic patterns and demographic histories of three endemic fishfly and dobsonfly species(Neochauliodes formosanus,Protohermes costalis,and Neoneuromus orientalis)belonging to the holometabolan order *** species,which share a broad and largely overlapping distribution,were analyzed using comprehensive mitogenomic *** findings revealed a consistent influence of vicariance on the population isolation of *** and *** between Hainan,Taiwan,and the East Asian mainland during the early Pleistocene,potentially hindering subsequent colonization of the later diverged *** to these ***,we unveiled the dual function of the major mountain ranges in East Asia,serving both as barriers and conduits,in shaping the population structure of all three ***,we demonstrated that these co-distributed species originated from Southwest,Southern,and eastern Central China,respectively,then subsequently migrated along multi-directional routes,leading to their sympatric distribution on the East Asian ***,our results highlighted the significance of Pleistocene land bridges along the eastern coast of East Asia in facilitating the dispersal of mountain-dwelling insects with low dispersal ***,this study provides novel insight into the synergistic impact of Pleistocene geological and climatic events in shaping the diversity and distribution of aquatic insects in East Asia.

关键词： Comparative phylogeography Island biogeography Pleistocene glaciation Corydalidae East Asia

Ultrahard X-ray multifunctional application beamline at the SSRF

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Nuclear Science and Techniques 2024年第6期35卷 14-25页

作者： Ke Yang Zhao-Hui Dong Chun-Yin Zhou Zi-Long Zhao Dong-Xu liang Sai-Chao cao ai-Guo li Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China

The ultrahard X-ray multifunctional application beamline(BL12SW)is a phase-II beamline project at the Shanghai Syn-chrotron Radiation *** primary X-ray techniques used at the beamline are high-energy X-ray diffraction and imaging using white and monochromatic *** main scientific objectives of ultrahard X-ray beamlines are focused on two research *** is the study of the structural properties of Earth’s interior and new materials under extreme high-temperature and high-pressure conditions,and the other is the characterization of materials and processes in near-real service *** beamline utilizes a superconducting wiggler as the light source,with two diamond windows and SiC discs to filter out low-energy light(primarily below 30 keV)and a Cu filter assembly to control the thermal load entering the subsequent optical *** beamline is equipped with dual *** first was a meridional bending Laue monochromator cooled by liquid nitrogen,achieving a full-energy coverage of 30-162 *** second was a sagittal bending Laue monochromator installed in an external building,providing a focused beam in the horizontal direction with an energy range of 60-120 *** were four experimental hutches:two large-volume press experimental hutches(LVP1 and LVP2)and two engineering material experimental hutches(ENG1 and ENG2).Each hutch was equipped with various near-real service conditions to satisfy different *** example,LVP1 and LVP2 were equipped with a 200-ton DDIA press and a 2000-ton dual-mode(DDIA and Kawai)press,***1 and ENG2 provide in situ tensile,creep,and fatigue tests as well as high-temperature *** June 2023,the BL12SW has been in trial *** is expected to officially open to users by early 2024.

关键词： Shanghai Synchrotron Radiation Facility Ultrahard X-ray High energy diffraction High energy imaging Engineering materials Earth science

Evolution and Governance of the Structure of Marine Economic Networks in China’s Coastal Areas: Based on Sea-related A-share listed Companies

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Chinese Geographical Science 2024年第5期34卷 899-916页

作者： li Bo cao Gai Key Research Base of Humanities and Social Sciences of Ministry of Education Institute of Marine Sustainable DevelopmentLiaoning Normal UniversityDalian 116029China School of Maritime Economics and Management Dalian Maritime UniversityDalian 116026China

Data on discrete,isolated attributes of the marine economy are often used in traditional marine economic ***,as the focus of urban research shifts from internal static attributes to external dynamic linkages,the importance of marine economic net-work research is beginning to *** construction of the marine economic network in China’s coastal areas is necessary to change the flow of land and sea resources and optimize regional marine economic *** data from headquarters and branches of sea-related A-share listed enterprises to construct the marine economic network in China,we use social network analysis(SNA)to discuss the characteristics of its evolution as of 2010,2015,and 2020 and its *** following results were obtained.1)In terms of topological characteristics,the scale of the marine economic network in China’s coastal areas has accelerated and expan-ded,and the connections have become increasingly close;thus,this development has complex network characteristics.2)In terms of spatial structure,the intensity of the connection fluctuates and does not form stable development support;the group structure gradually becomes clear,but the overall pattern is fragmented;there are spatial differences in marine economic agglomeration radiation;the radi-ation effect of the eastern marine economic circle is obvious;and the polarization effect of northern and southern marine economic circles is *** this basis,we construct a framework for the governance of a marine economic network with the market,the government,and industry as the three governing *** clarifying the driving factors and building objectives of marine economic network construction,this study aims to foster the high-quality development of China’s marine economy.

关键词： marine economic network sea-related A-share listed companies social network analysis(SNA) network governance China’s coastal areas

Particles attrition of binary mixtures in the coal-fueled chemical looping system based on fluidized bed

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Particuology 2024年第3期86卷 281-290页

作者： Heyu li Zhe Sun Yan cao Guangzhou Institute of Energy Conversion Chinese Academy of SciencesGuangzhou 510640China University of Chinese Academy of Sciences Bejing 100049China CAS Key Laboratory of Renewable Energy Guangzhou 510640China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640China College of Chemistry and Chemical Engineering Anhui UniversityHefei230601China

In this work,a reactive air jet attrition device with auto-recording and collection of elutriated fines was *** established insights into the physiochemical interaction and further correlated attrition behaviors between char and oxygen carriers under various operation *** attrition rate increased by over 110% upon the introduced CO_(2),which brought in the significant effect of thermo-chemical stress,similarly in effects of the increased char addition ratio and the decreased sizes of char or hematite in different *** the char-hematite co-attrition process,the elutriated carbon loss of char with poor mechanical strength was found to be over 10%,while the reactive iron loss of hematite was found to be 6.3%,and was enriched in elutriated *** reaction-derived thermochemical stress and the collision-derived mechanical stress jointly controls the particle attrition during the cyclic transformation of oxygen carrier particles in coal-fueled chemical looping fluidization,especially sig-nificant in its reduction stage.

关键词： Attrition Binary species Chemical looping Oxygen carrier CO_(2)capture

Reinforcing effects of polypropylene on energy absorption and fracturing of cement-based tailings backfill under impact loading

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 650-664页

作者： Jiajian li Shuai cao Erol Yilmaz School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology BeijingBeijing 100083China Department of Civil Engineering Geotechnical DivisionRecep Tayyip Erdogan UniversityFenerRize TR53100Turkey

Polypropylene(PP)fiber-reinforced cement-based tailings backfill(FRCTB)is a green compound material with superior crack resistance and has good prospects for application in underground ***,FRCTB exhibits susceptibility to dynamic events,such as impact ground pressure and blast *** paper investigates the energy and crack distribution behavior of FRCTB under dynamic impact,considering the height/diameter(H/D)*** Hopkinson pressure bar,industrial computed tomography scan,and scanning electron microscopy(SEM)experiments were carried out on six types of *** outcomes confirmed fiber aggregation at the bottom of *** H/D was less than 0.8,the proportion of PP fibers distributed along theθangle direction of80°-90°*** the total energy,all samples presented similar energy absorption,reflectance,and ***,a rise in H/D may cause a rise in the energy absorption rate of FRCTB during the peak phase.A positive correlation existed between the average strain rate and absorbed energy per unit *** increase in H/D resulted in a decreased crack volume fraction of *** the H/D was greater than or equal to 0.7,the maximum crack volume fraction of FRCTB was observed close to the incidence *** cracks were present only in the FRCTB with an H/D ratio of *** with H/D ratios of 0.5 and 0.6 showed similar distributions of weakly and heavily damaged *** fibers can limit the emergence and expansion of cracks by influencing their *** observations revealed considerable differences in the bonding strengths between fibers and the *** that adhered particularly well to the substrate were attracted together with the hydration products adhering to *** results show that FRCTB is promising as a sustainable and green backfill for determining the design properties of mining with backfill.

关键词： cement-based tailings fiber-reinforced backfills fracture energy absorption impact loading

Microstructural evolution and strengthening mechanism of aligned steel fiber cement-based tail backfills exposed to electromagnetic induction

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International Journal of Minerals,Metallurgy and Materials 2024年第11期31卷 2390-2403页

作者： Xihao li Shuai cao Erol Yilmaz School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology BeijingBeijing 100083China Department of Civil Engineering Geotechnical DivisionRecep Tayyip Erdogan UniversityFener Rize TR53100Turkey

Cemented tailings backfill(CTB)not only boosts mining safety and cuts surface environmental pollution but also recovers ores previously retained as pillars,thereby improving resource *** use of alternative reinforcing products,such as steel fiber(SF),has continuously strengthened CTB into *** approach prevents strength decreases over time and reinforces its long-term durability,especially when mining ore in adjacent underground *** this study,various microstructure and strength tests were performed on SFCTB,considering steel fiber ratio and electromagnetic induction strength *** findings show that combining steel fibers and their distribution dominantly influences the improvement of the fill’s ***’s strength rises by fiber insertion and has an evident correlation with fiber insertion and magnetic induction *** magnetic induction strength is 3×10^(-4) T,peak uniaxial compressive stress reaches 5.73 MPa for a fiber ratio of 2.0vol%.The cracks’expansion mainly started from the specimen’s upper part,which steadily expanded downward by increasing the load until damage *** doping of steel fiber and its directional distribution delayed crack *** the doping of steel fiber was 2.0vol%,SFCTBs showed excellent ductility *** energy required for fills to reach destruction increases when steel-fiber insertion and magnetic induction strength *** study provides notional references for steel fibers as underground filling additives to enhance the fill’s durability in the course of mining operations.

关键词： electromagnetic induction steel fiber cemented tailings backfill strength microstructure

Classifying hepatitis B therapies with insights from covalently closed circular DNA dynamics

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Virologica Sinica 2024年第1期39卷 9-23页

作者： Jie-li Hu ai-Long Huang Key Laboratory of Molecular Biology on Infectious Diseases Ministry of EducationChongqing Medical UniversityChongqing400016China

The achievement of a functional cure for chronic hepatitis B(CHB)remains limited to a minority of patients treated with currently approved *** primary objective in developing new anti-HBV drugs is to enhance the functional cure rates for CHB.A critical prerequisite for the functional cure of CHB is a substantial reduction,or even eradication of covalently closed circular DNA(cccDNA).Within this context,the changes in cccDNA levels during treatment become as a pivotal *** have previously analyzed the factors influencing cccDNA dynamics and introduced a preliminary classification of hepatitis B treatment strategies based on these *** this review,we employ a systems thinking perspective to elucidate the fundamental aspects of the HBV replication cycle and to rationalize the classification of treatment strategies according to their impact on the dynamic equilibrium of *** upon this foundation,we categorize current anti-HBV strategies into two distinct groups and advocate for their combined use to significantly reduce cccDNA levels within a well-defined timeframe.

关键词： Hepatitis B cccDNA Functional cure Dynamics Treatment Strategy

Thermosphere joint observations by TM-1 constellations and Swarm-B during the April 2023 geomagnetic storm

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Earth and Planetary Physics 2024年第2期8卷 307-316页

作者： YongPing li YueQiang Sun XianGuo Zhang JiangZhao ai Xiaoliang Zheng Jia li YuJie Wang BiBo Guo Feng Yan ShiLong Wei XinChun Tang YuanYuan cao National Space Science Center Chinese Academy of SciencesBeijing 100190China Beijing Key Laboratory of Space Environment Exploration Beijing 100190China Key Laboratory of Science and Technology on Space Environment Situational Awareness Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Shenzhen Aerospace Dongfanghong Satellite LtdShenzhen 518057China

The response of thermosphere density to geomagnetic storms is a complicated physical ***-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been *** this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B *** observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic *** observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the *** TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were ***-B data exhibit near-symmetry between the *** addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric *** South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%*** the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite ***00 model simulations were also performed on this geomagnetic *** are absent in the NRLMSISE00 *** satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both ***,use of the density simulation of NRLM

关键词： TM-1 constellation Swarm-B joint observations geomagnetic storm Local Times