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Challenges and opportunities in Quaternary palynology

Science China Earth Sciences 2024年第7期67卷 2148-2161页

作者： Qinghai XU Houyuan LU zhuo Z{1. College of Geographical Sciences Hebei Key Laboratory of Environmental Change and Ecological ConstructionHebei Normal UniversityShijiazhuang 050024China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Earth Sciences and Engineering Sun Yat-sen UniversityZhuhai 519082China

Quaternary palynology plays a pivotal role in investigating global climate change and various other research fields,serving as an essential tool for the quantitative analysis of paleoenvironment ***,due to the vast diversity of terrestrial ecosystems and intricate interactions between vegetation,climate,and human activities,further advancements are required in the following aspects within this discipline.(1.The accuracy of classification in pollen morphology and fossil pollen identification needs improvement,particularly at the species *** represents a significant challenge in present Quaternary ***-aided intelligent recognition holds promise as a solution for species identification based on more detail pollen morphology.(2)Most pollen-based vegetation and climate reconstructions overlook the significance of bare *** bare ground can lead to substantial inaccuracies when quantitatively reconstructing past vegetation and climate.(3)While pollen records provide reliable information on paleoclimate changes,current quantitative climate reconstruction models heavily rely on modern pollen datasets derived from present-day vegetation disturbed more or less by human *** introduces bias and uncertainties into paleoclimate reconstruction.(4)Although pollen can serve as an indicator of human activities,accurately quantifying the intensity of human influence remains *** accurate identification of crop pollen,reconstructing reliable land cover/use data,and integrating multidisciplinary data may enhance the identification and quantification of signals related to human activity in pollen records.

关键词： Quaternary palynology Paleoclimate Paleovegetation Human activity

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Characteristics and origin of low-organicmatter carbonate source rocks in the Middle-Upper Ordovician, Tarim Basin, northwestern China

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Journal of Palaeogeography 2024年第3期13卷 594-619页

作者： Jun-Qing Chen Fu-Jie Jiang Xiong-Qi Pang Hai-Jun Yang Kan-Yuan Shi Bo Pang Hong Pang Jian-Fa Chen zhuo-{1. Chen Xin-Gang Zhang Song Wu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China Basic Research Center for Energy Interdisciplinary College of ScienceChina University of Petroleum(Beijing)Beijing 102249China Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum(Beijing)Beijing 102249China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China Research Institute of Petroleum Exploration and Development PetroChina Tarim Oilfield CompanyKorla 841000Xinjiang Uygur Autonomous RegionChina Geological Survey of Canada Natural Resources CanadaCalgary T2L 2A7Canada

The continually-discovered large volumes of marine hydrocarbons indicate a huge exploration potential within the carbonate rocks of Ordovician in the Tarim Basin,northwestern *** Middle-Upper Ordovician(O2+3)carbonate source rocks are at a highly mature *** rocks presently contain a low amount of total organic carbon(TOC_(pd)≤0.5%)(TOC_(pd) means the present-day TOC).A mass balance approach is used to identify the source rocks that have expelled *** characteristics and origin of hydrocarbon expulsion from low-TOC_(pd) source rocks are studied,which are significant for oil exploration in the *** results showed that a low-TOC_(pd) O2+3 source rock having expelled hydrocarbons was type I and had a very narrow oil *** a high rock maturity and a high original TOC(TOCo)value exceeding 1.,nearly 80%of the generated hydrocarbons were *** content of gammacerane and C28 steranes in the oil and source rock extracts were relatively lean,with a V-shaped distribution of regular steranes,suggesting a possible genetic relation between the low-TOC_(pd) source rocks and the marine oil in the Tabei *** planktonic algae or acritarchs were the main hydrocarbon parent materials,distributed in the subsiding platform-slope *** matter was preserved under reducing conditions,and source rocks were formed with a favorable kerogen type and a moderate hydrocarbon generation *** study illustrates the hydrocarbon expulsion of low TOC_(pd) source rocks in northern Tarim Basin,which is greatly significant for analyzing the genesis of marine crude oil in Tarim Basin,and evaluating the distribution of marine source *** research method is theoretically significant for oil and gas exploration in the same type of highlymature carbonate paleobasins.

关键词： Carbonate source rock Mass balance approach Present-day TOC Genesis mechanism Tarim Basin

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Preparation,optical properties and energy transfer of SrLaAlO4:Dy3+,Eu3+

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Journal of Rare Earths 2024年第11期42卷 2058-2067页

作者： Wei Chen heng Zhang Desheng Zhu School of Physic and Optoelectronic Engineering Yangtze University

A series of Dy3+/Eu3+single doped and co-doped SrLaAlO4phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were *** X-ray diffraction（XRD） shows a small amount of doping with Dy3+and Eu3+does not change the crystal structure of the matrix SrLaAlO4and the best synthesis temperature is 1.50℃.The scanning electron microscopy（SEM） indicates the particle size directly ranges from 1.to 5μm roughly and the energy dispersive spectroscopy（EDS） patterns show that SrLaAlO4:Dy3+phosphor and SrLaAlO4:Dy3+,Eu3+phosphor were successfully ***4:Dy3+phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm（blue light） and 579 nm（yellow light）,presenting a cold white light;SrLaAlO4:Eu3+phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy3+and Eu3+can be shown simultaneously under the same excitation wavelength in SrLaAlO4:Dy3+, Eu3+*** changing the relative doping concentration ratio of Dy3+and Eu3+,the modulation of SrLaAlO4:Dy3+,Eu3+phosphor from cold white to warm white light can be *** addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy3+and Eu3+in SrLaAlO4:Dy3+,Eu3+phosphor.

关键词： Energy transfer High-temperature solid-phase method Luminescence properties Rare earths SrLaAlO4: Dy3+, Eu3+ White phosphor

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Effects of the nozzle structure and fluidized gas composition on the gas-particle two-phase jet characteristic in a powder fuel scramjet

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Particuology 2024年第9期92卷 166-179页

作者： Changfei zhuo Hongming Ding Xiaobin Ren Hanyu Deng Xiong Chen School of Mechanical and Engineering Key Laboratory of Special Engine TechnologyMinistry of EducationNanjing University of Science and TechnologyNanjing210094China Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore117576 Shanxi North Xing'an Chemical Industry Co. Ltd.Taiyuan030008China

The interaction between nozzle design and fluidization gas composition significantly influences the dynamics within a powder fuel scramjet's combustion *** investigate this relationship,an experimental study utilized high-speed shadow imaging technology to explore the macroscopic aspects of powder fuel *** investigation examined various convergence angles,nozzle throat lengths,and fluidized gas *** findings include:During jet development,powder fuel initially concentrates near the axis,with non-convergence angle nozzles exhibiting longer concentrated distribution periods than convergence angle *** nozzle convergence angles lead to increased penetration distance,frontal velocity,and radial diffusion distance during the initial stages of jet ***,stable jet shapes show larger divergence angles as nozzle convergence angle decreases,with the largest divergence angle observed atα=60°.In the initial 0-7 ms of jet development,the powder fuel jet demonstrates greater penetration distance and frontal velocity under certain ***,penetration distance and frontal velocity increase with throat length from 7 to 20 ms,accompanied by changes in divergence ***,at a throat length(l)of 2 mm,the near-field divergence angle measures 46.50°,and the far-field divergence angle is 22.25°.Conversely,at l=8mm,the near-field divergence angle is 33.49°,and the far-field divergence angle is 23.21..The fluidization gas composition minimally affects jet penetration distance and frontal velocity during the initial 0-3 ***,due to hydrogen's low density,hydrogen/powder fuel jets exhibit shorter distances and velocities compared to nitrogen/powder fuel *** fluidization also results in larger divergence angles,particularly in the near *** findings underscore the importance of nozzle design and fluidization gas composition in optimizing scramjet performance and efficiency.

关键词： Multiphase flows Gas-particle two-phase jet Nozzle contraction angle Powder fuel scramjet

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Finite Groups with Some Bounded Codegrees

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1778-1784页

作者： Dong Fang YANG Yu ZENG heng LV School of Mathematics and Statistics Southwest UniversityChongqing400715P.R.China Department of Mathematics Changshu Institute of TechnologyChangshu215500P.R.China

For a characterχof a finite group G,the number cod(χ) := ∣G:ker(χ)∣/χ(1.is called the codegree ofχ.In this paper,we give a solvability criterion for a finite group G depending on the minimum of the ratioχ(1.^(... 详细信息

关键词： Finite group codegree degree simple group

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Three-dimensional forest foodscape in large herbivores’habitat based on UAV with LiDAR detection

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Integrative Zoology 2024年第2期19卷 343-346页

作者： heng BAO Guangshun JIANG College of Wildlife and Protected Area Northeast Forestry UniversityHarbinChina Feline Research Center of National Forestry and Grassland Administration HarbinChina Research Center for Northeast Asia Biodiversity Conservation HarbinChina

Traditionally,wildlife habitat research mainly extracts two-dimensional habitat ***,they live in three-dimensional space,and the three-dimensional structure of the forest ecosystem is an important factor affecting the composition of the mammal community(Fig.1.,b),and the three-dimensional structure of the forest also determines the behavior pattern of wildlife multidimensional habitat selection or use(Flaspohler et al.201.;Palminteri et al.201.;Müller et al.201.).For instance,forest structure determines the vertical distribution of annual edible shoots,fruits,or seed nuts resources in space,providing additional ecological niches for frugivores,rodents,and other species,and then leading to niche differentiation of wild animals in vertical space utilization,thus increasing species coexistence(*** et al.2023).

关键词： habitat forest dimensional

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Photostriction effect and electric properties of La-doped PMN-PT transparent ferroelectric ceramics

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International Journal of Smart and Nano Materials 2024年第2期15卷 296-311页

作者： Zhiqiang Song zhuo Zhang Yirong Yu Dabin Lin Department of Automation and Robotics Engineering School of AutomationWuxi UniversityWuxiChina School of Optoelectronic Engineering Xian Technological UniversityXi'anChina

Ferroelectric ceramics display a remarkable photostriction effect,which could facilitate the prevention of electromagnetic interference and promote the integration and miniaturization of actuator systems,indicating potential applications in glim-mer *** this work,highly transparent La-doped 0.9Pb(Mg1.3Nb2/3)O3-0.1.bTiO3(0.9PMN-0.1.T)ceramicswere synthesized using a solid-state reaction method in an oxyge-nated *** and SEM were used to analyze the phase structure of the dense samples,which displayed a pure perovskite structure,with no trace of a pyrochlore *** La doping,the phase transitiontemperature shows a decreasing trend,and its dielectric constant could reach up to 20,*** P-E loop of the samples was gradually refined into a straight line with an increase in the doping *** La doping,the transparency of the 0.9PMN-0.1.T cera-mics was significantly enhanced and reached up to 61.at the near-infrared ***,the photogenerated voltage and deformation of the La-doped 0.9PMN-0.1.T ceramics were investigated under ultraviolet light of various *** 20 s of irradiation at an intensity of 800 mW/cm²,the max-imum voltage and deformation,with values of 40 V and 250 nm,respectively,were both found in the 1.La-doped 0.9PMN-0.1.T ceramics.

关键词： Photostriction ferroelectric Raman piezoelectric

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Improving fault localization with pre-training

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Frontiers of Computer Science 2024年第1期18卷 247-249页

作者： zhuo ZHANG Ya LI Jianxin XUE Xiaoguang MAO School of Information Technology and Engineering Guangzhou College of CommerceGuangzhou 511363China Ningbo Artificial Intelligence Institute Shanghai Jiao Tong UniversityNingbo 315000China Institute for Artificial Intelligence Shanghai Polytechnic UniversityShanghai 210209China College of Computer National University of Defense TechnologyChangsha 410073China

1.Introduction For developers,fault localization is the most tedious and time-consuming *** order to reduce the burden of developers,researchers have developed various techniques to help reduce the cost of locating faults based on possibility of containing a fault in program statements[1..Among them,coverage-based fault localization is one of the most studied automated fault localization ***-based fault localization methods utilize a type of preliminary information to localize the faults in programs,which is a matrix of statements’coverage *** value of each element is 1.or 0,in which 1.means a statement is executed and 0 denotes a statement is not executed[1..

关键词： fault statement utilize

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In situ reduction strategy towards high conductivity,anti-freezing and super-stretchable rGO based hydrogel for diverse flexible electronics

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Nano Research 2024年第5期17卷 4016-4022页

作者： Xin Zhang Junhao Wang Mengyan Wang Dongxu Liu zhuo Wang College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of ScienceBeijing 101400China

Hydrogels electrolytes with flexibility and high conductivity have been widely used in kinds of flexible ***,hydrogels always suffer from the inevitable freezing of water at subzero temperatures,which results in the sacrificing of their electrical ***,an anti-freezing,flexible hydrogel based on in situ reduction of graphene oxide(GO)and laponite has been developed as electrolyte for high performance supercapacitor and sensitive *** crosslinked GO and laponite in polyacrylamide(PAM)resulted in an enhanced mechanical property,while the in-situ reduction of GO in the hydrogel enhanced the conductivity and diminishes the aggregated of *** features guarantee a reliable electro signal as sensor and a high performance of the ***,in the process of preparation of reduced graphene oxide(rGO)hydrogel,the addition of ethylene glycol(EG)and KOH,endows the hydrogel antifreeze *** anti-freezing electrolyte can be stretched to a strain of 1.00%and maintained a specific capacitance of 37.38 F·g^(-1. at-20℃.In addition,the photothermal conversion character of rGO in the hydrogel,endows it’s the potential application in wound *** overall merits of the hydrogel will open up a new avenue for sensitive sensor and energy storage device in practical applications.

关键词： hydrogel in-situ reduction flexible electronics low temperature tolerance photothermal therapy

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Phase-field simulation of precipitation kinetics and creep properties of Ni-Al-Cr/Ta superalloys

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Science China(Technological Sciences) 2024年第4期67卷 1139-1150页

作者： YANG ShuaiGe ZHANG Zan zhuo JiC{1. LONG HongLi LI YongS{1. National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China

The precipitation kinetics ofγ'-Ni_(3)(Al,Ta)phase and creep properties of Ni-1.Al-x Ta at.%superalloys are investigated by the crystal plasticity phase-field *** results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage,while the creep lifetime is *** large external strain intensifies the creep damage and shortens the creep life of Ni-1.Al-3Ta at.%*** kinetics evolution and elements distribution are revealed in the quaternary Ni-1.Al-8.5Cr-xT a(x=1.5 at.%,2.0 at.%,2.5 at.%)superalloys by the multi-component phase-field *** anti-phase boundary(APB)changes the coarsening mechanism ofγ'phase,and Ta promotes the precipitation ofγ'phase with an increasing volume fraction and particle *** composition difference betweenγ'andγphases increases with the rising of Ta content,the strong partitioning of Ta toγ'phase strengthens the partitioning of Ni and Cr toγmatrix,and Ta shows a superiority than Al in the lattice site occupation of L1.(2)-Ni_(3)(Al,X)*** an importantγ'phase forming element,the optimization of Ta content is essential for improving the mechanical properties of Ni-based superalloys.

关键词： Ni-Al-Ta alloys creep properties kinetics phase-field

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