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Metastable magnetic behavior in La_(0.9)Tb_(0.1)MnO_3

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Rare Metals 2017年第7期36卷 596-600页

作者： Wei-Bin Liu Ying-Tang Zhang Zi-Yu Chen Li-Zhu Liu Sheng-tao Li tao-tao ai Department of Physics Beijing University of Aeronautics and Astronautics School of Material Science and Engineering Institute of Functional MaterialShaanxi University of Technology Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and Technology State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University

The linear and nonlinear magnetizations of La0.9Tb0.1MnO3 at low temperatures were reported in de- tail. The temperature dependence of magnetization shows peaks at 50, 100 and 150 K, respectively. When LaMnO3 is Tb-doped, its magnetic structure exhibits a canted an- tiparallel spin order. This is different from classical antiferromagnetic （AFM） in which the relaxation behavior takes place at about 150 K. At 50 K, Tb-doped LaMnO3 exhibits canonical spin glass behavior, arising from the competition of exchange and super-exchange between spins. The peak at 100 K shows neither spin glass behavior nor canted AFM behavior. Its peak value increases with frequency increasing, and the transition temperature of the peak shifts to higher temperatures with frequency increasing. The study of aging behavior at 100 K shows a periodical variable metastability, which is ascribed to the competition between ferromagnetic （FM）-, AFM- and sinusoidal-order interactions. This work should shed a light on understanding the complex magnetic structure of the perovskite oxides.

关键词： La0.9Tb0.1MnO3 Relaxation behavior Metastability

Paleogene integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth Sciences 2024年第4期67卷 1290-1325页

作者： Jia LIU ai SONG Lin DING tao SU Zhekun ZHOU CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Institute of Paleontology Yunnan UniversityKunming 650500China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

The Paleogene is a crucial period when terrestrial and marine ecosystems recovered from major disruptions and gradually approached their modern *** the Qinghai-Tibetan Plateau and its surrounding regions,the Paleogene also represents a significant phase of tectonic evolution in the Qinghai-Tibetan Plateau-Himalaya orogeny,reorganization of Asian climates,and evolution of *** to limitations in research conditions and understanding,there are still many controversies regarding stratigraphic divisions in the Qinghai-Tibetan Plateau and its surrounding *** recent years,extensive studies on sedimentary petrology,magnetostratigraphy,and isotope dating have been conducted in the *** fossils have been discovered and reported,contributing to a more systematic understanding of *** studies have laid a solid foundation for the comprehensive investigation of the stratigraphy,biotas and paleogeographic evolution of the Qinghai-Tibetan Plateau and its surrounding regions during the *** this paper,we integrate recent research on fossils,isotopic dating,magnetostratigraphy,and geochemistry to refine the stratigraphic divisions and correlation framework of different tectonic units in the region,building upon previous *** the Second Tibetan Plateau Scientific Expedition and Research,the knowledge of Paleogene floras has gradually *** paper discusses the biostratigraphic significance of extinct and newly appeared taxa based on the latest dating results of these plant *** new understanding of fossil species such as the“Eucalyptus”and Arecaceae establishes connections between the Paleogene flora of the Qinghai-Tibetan region and the biotas of Gondwana,specifically Oceania and South *** evolutionary history of key taxa near the Yarlung Zangbo suture zone indicates that the collision between the Indian and Eurasian plates occurred approximately 65-54 *** reconstructions,based o

关键词： Qinghai-Tibetan Plateau Fossils Biostratigraphy Paleoenvironment Paleogeography Paleogene

China-EU Relations Face Unprecedented Development Opportunities——Notes on NPC Vice-Chairman Zhou Tienong's Visitto Europe

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International Understanding 2011年第4期 24-27页

作者： tao tao ai Hong

At the invitation of the Foundation of European Progressive Studies, the Belgium-ChinaParliamentary Friendship Group, and the Austria-China Friendship Association, Vice-Chairman of NPC Standing Committee and President of CAFIU Mr. Zhou Tienong headed a delegation of 14 members to the EU, Belgium and Austria for a good-will visit from July 2 to 13. During the visit, Mr.

关键词：全国人大常委会中国欧洲欧盟债券铁比利时奥地利

Localization of q-form fields on a de Sitter brane in chameleon gravity

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Frontiers of physics 2024年第3期19卷 11-18页

作者： Yi Zhong tao-tao Sui School of Physics and Electronics Science Hunan UniversityChangsha 410082China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China College of Physics Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Recently,it was found that the vector field can be naturally localized on the thick brane in chameleon *** this work,we extend this study to encompass de Sitter brane *** focus on the localization of q-form *** scalar and vector fields can be localized on the de Sitter brane,while the KR field cannot be *** condition for localization of the scalar and vector fields is ***,we investigate the localization characteristics in two examples with given conformal factor b(ϕ).In the first case,the effective potentials and KK modes of the matter fields are obtained asymmetric even though the de Sitter brane has Z2 *** the second case,volcano-like effective potentials are generated in the de Sitter brane model.

关键词： brane q-form field chameleon gravity

A Global Optimality Principle for Fully Coupled Mean-field Control Systems

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 379-413页

作者： tao HAO School of Statistics and Mathematics Shandong University of Finance and EconomicsJinan 250014China

This paper concerns a global optimality principle for fully coupled mean-field control *** the first-order and the second-order variational equations are fully coupled mean-field linear FBSDEs. A new linear relation is introduced, with which we successfully decouple the fully coupled first-order variational equations. We give a new second-order expansion of Y^(ε) that can work well in mean-field framework. Based on this result, the stochastic maximum principle is proved. The comparison with the stochastic maximum principle for controlled mean-field stochastic differential equations is supplied.

关键词： optimal control global maximum principle fully coupled general mean-field FBSDE adjoint equation recursive utility

Track-before-detect for bistatic radar based on pseudo-spectrum

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Chinese Journal of Aeronautics 2024年第1期37卷 236-246页

作者： tao HAN Gongjian ZHOU School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China Key Laboratory of Marine Environmental Monitoring and Information Processing Ministry of Industry and Information TechnologyHarbin 150001China

Track-Before-Detect(TBD) is an efficient method to detect dim targets for radars. Conventional TBD usually follows an approximate motion model of the target, which may cause an inaccurate integration of the target energy. A TBD technique on basis of pseudo-spectrum in mixed coordinates adopting an accurate motion model for bistatic radar system is developed in this *** predicted position in bistatic polar plane is derived according to a nonlinear function that exactly describes the constant Cartesian velocity motion. Then around the predicted position, a pseudo-spectrum is formulated and its samples are accumulated to the integration frame for energy integration. The evolution of the state and the procedure of accumulation of the target energy are derived elaborately. The superior performance of the proposed method is demonstrated by some simulations.

关键词： Weak target detection Bistatic radar Track-before-detect Pseudo-spectrum Multiframe integration

Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

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Journal of Thermal Science 2024年第3期33卷 1132-1147页

作者： JIANG tao LI Mingjia Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081China

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good ***,due to the large variety of PCHE configurations,channel selection in practical applications lacks a ***,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE ***,the comprehensive performance of four channels was ***,the heat transfer and friction factor correlations for S-CO_(2)in four channels were *** findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively *** zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat *** sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded *** streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance *** the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting *** research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.

关键词： printed circuit heat exchanger supercritical carbon dioxide typical channel structure field synergy analysis

Gas-surface interaction features under effects of gas-gas molecules interaction in high-speed flows

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Chinese Journal of Aeronautics 2024年第5期37卷 228-242页

作者： Ruiling tao Zhihui WANG School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Understanding interactions between gas molecules and solid surface is key to the aerodynamic design of high-speed,high-altitude aerospace vehicles,but there is a large dispersion of gas-surface interaction parameters or namely accommodation *** uncertainty results partly from different considerations of the interaction between gas molecules in various experimental and numerical *** this study,effects of gas-gas molecules interaction are systematically discussed by comparing two different approaches of molecular dynamics simulation of high-speed argon molecules scattering on a graphite *** popularly-used“single scattering”approach repeats the scattering process of a single gas molecule without considering the gas-gas molecules *** newly-developed“continual scattering”approach continually shoots gas molecules at the surface,considering collisions between gas molecules in addition to gas molecules’collisions with ***-surface interaction features in the two approaches are compared and discussed under various affecting factors including rarefaction degree,gas-surface interaction strength,surface temperature and incident *** is shown that these two approaches usually produce different accommodation coefficients,and the corresponding mechanisms are *** study could help clarify some doubts about the selection of accommodation coefficients in engineering practice,and also provide an instruction on design of an appropriate molecular dynamics simulation approach.

关键词： Gas-surface interaction Molecular dynamics Accommodation coefficient Aerospace vehicles High-speed flow

On m-ovoids of finite classical polar spaces with an irreducible transitive automorphism group

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Science China Mathematics 2024年第3期67卷 683-712页

作者： tao Feng Weicong Li Ran tao School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Department of Mathematics and National Center for Applied Mathematics Shenzhen Southern University of Science and TechnologyShenzhen 518055China Key Laboratory of Cryptologic Technology and Information Security Ministry of EducationShandong UniversityQingdao 266237China School of Cyber Science and Technology Shandong UniversityQingdao 266237China

In this paper, we classify the m-ovoids of finite classical polar spaces that admit a transitive automorphism group acting irreducibly on the ambient vector space. In particular, we obtain several new infinite familie... 详细信息

关键词： transitive m-ovoids irreducible action finite classical polar spaces primitive divisor