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Reconstructing the flux-rope topology using the FOTE method

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Science China(Technological Sciences) 2019年第1期62卷 144-150页

作者： CHEN ZuZheng FU HuiShan WANG TieYan CAO Dong PENG FangZheng YANG Jian XU Yin School of Space and Environment Beihang UniversityBeijing 100083China

With high-resolution data of the Magnetospheric Multiscale(MMS) mission, we observe a magnetic flux rope(MFR) in the Earth's magnetosheath. This MFR, showing a clear bipolar variation of the magnetic field in the normal component to local current sheet, contains a strong core field. We use the FOTE method to reconstruct the topology of this MFR and find it is consistent with previous expectation. For the first time, the spiral field and core field of the MFR are both revealed from the FOTE method. Comparing topologies reconstructed at different times, we suggest that the axis of the MFR rotates about 88° at different spatial location. Shape and size of the normal projection to axis vary with the spatial location as well. Inside the MFR, a significant increase of plasma density from 40 to 80 cm^(-3), a sharp decrease of ion temperature from 200 to 50 eV, an enhancement of cold ions and a series of filamentary currents are found.

关键词： magnetic flux rope First-Order Taylor Expansion (FOTE)method reconstructing three-dimensional topology

Uncovering the underlying physical mechanisms of biological systems via quantification of landscape and flux

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Chinese Physics B 2016年第1期25卷 244-269页

作者：徐丽楚夏昆晏致强郑喜亮张坤张锋闫晗吴畏汪劲 State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Department of Chemistry and Physics Stony Brook UniversityStony BrookNY 11794-3400USA

In this review, we explore the physical mechanisms of biological processes such as protein folding and recognition, ligand binding, and systems biology, including cell cycle, stem cell, cancer, evolution, ecology, and neural networks. Our approach is based on the landscape and flux theory for nonequilibrium dynamical systems. This theory provides a unifying principle and foundation for investigating the underlying mechanisms and physical quantification of biological systems.

关键词： landscape flux

A comparison study on viscosity and heat transfer property of fluorinebearing and fluorine-free mold flux for casting silicon steel

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Journal of Iron and Steel Research International 2019年第4期26卷 385-392页

作者： De-xiang Cai Wan-lin Wang Lei Zhang Chen Zhang School of Metallurgy and Environment Central South UniversityChangsha 410083HunanChina Steelmaking Research Department Baosteel Group Corporation Research InstituteShanghai 201900China

A comparison study was conducted on viscosity and heat transfer property of the traditional fluorine-bearing(F-bearing)mold flux and the newly designed fluorine-free(F-free)mold flux for casting silicon *** results showed that the viscosity of F-free mold flux is lower than that of F-bearing mold flux,as the apparent activation energy of F-free mold flux is also lower than that of F-bearing mold flux confirmed by the kinetics results for viscous flow,which meant that the energy barrier of F-free mold flux that the migration of ion clusters needs to overcome is smaller,and thus leads to a lower viscosity of F-free mold ***,the research results of the heat transfer suggested that the comprehensive heat transfer coefficient of F-free mold flux is lower than that of F-bearing mold flux in all *** reason is that the true density of F-free mold flux increases from glassy state to crystalline state,while that of F-bearing mold flux is *** reason is that the air gap gets increased due to the volume shrinkage of F-free mold flux from glassy state to crystalline state and the solidification of the molten *** introduce a larger thermal resistance of F-free mold flux than that of F-bearing mold *** the comparison,the designed F-free mold flux shows a better lubrication and capacity to control the heat transfer than the traditional F-bearing mold flux.

关键词： Silicon steel Mold flux Viscosity True density Heat transfer

A numerical study for WENO scheme-based on different lattice Boltzmann flux solver for compressible flows

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Acta Mechanica Sinica 2018年第6期34卷 995-1014页

作者： You Li Xiao-Dong Niu Hai-Zhuan Yuan Adnan Khan Xiang Li College of Engineering Shantou UniversityShantou 515063China School of Mathematics and Computational Science Xiangtan UniversityXiangtan 411105China

In this paper,the finite difference weighted essentially non-oscillatory (WENO) scheme is incorporated into the recently developed four kinds of lattice Boltzmann flux solver (LBFS) to simulate compressible flows,including inviscid LBFS Ⅰ,viscous LBFS Ⅱ,hybrid LBFS Ⅲ and hybrid LBFS Ⅳ.Hybrid LBFS can automatically realize the switch between inviscid LBFS Ⅰ and viscous LBFS Ⅱ through introducing a switch *** resultant hybrid WENO-LBFS scheme absorbs the advantages of WENO scheme and hybrid *** investigate the performance of WENO scheme based on four kinds of LBFS *** results indicate that the devopled hybrid WENO-LBFS scheme has high accuracy,high resolution and no *** can not only accurately calculate smooth solutions,but also can effectively capture contact discontinuities and strong shock waves.

关键词： WENO scheme Hybrid Lattice Boltzmann flux solver Compressible inviscid flows Contact discontinuities Shock waves

The landscape and flux of a minimum network motif,Wu Xing

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Chinese Physics B 2020年第12期29卷 186-197页

作者： Kun Zhang Ashley Xia Jin Wang State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China The U.S.Center for Chinese Medicine by Beijing University of Chinese Medicine 15005 Shady Groove RoadSuite 410RockvilleMD 20850USA Department of Chemistry and Physics Department of Applied MathematicsState University of New York at Stony BrookStony BrookNY 11794USA

Wu-Xing theory is an ancient philosophy that serves as a guiding principle in the traditional Chinese medicine(TCM).It has been used to explain the unbalance among the TCM organ systems in disease states and provide treatment philosophy *** now,it is still a challenge to explore the Wu-Xing theory beyond its philosophical *** this study,we established a quantitative framework using the landscape and flux theory to characterize the nature of the WuXing theory from a perspective of a minimal network motif and leave certain specific functional aspects of Wu-Xing theory for future *** uncovered the irregular ring shape of projection landscape for the Wu-Xing network with several local basins and *** found that the dynamics of the self-organized Wu-Xing system was determined by the underlying negative landscape gradient force and the nonequilibrium rotational *** the shape of the WuXing landscape determines the stabilities of the states,the rotational flux guarantees the persistent periodic oscillation and the stability of the *** provides a physical and quantitative basis for Yin–Yang duality of the driving forces for determining the dynamics and behaviors of the living *** landscape and flux analysis,we can identify the key parameter for the dynamics/function of Wu-Xing *** findings allow us to have a deeper understanding of the scientific merits of the ancient Wu-Xing theory from the network motif perspective.

关键词： traditional Chinese medicine nonequilibrium landscapes flux

An Analytical Model Based on the Theory of Constant Heat flux Ratio Across the Frozen Layer for Solving Planar, Cylindrical and Spherical Freezing Problems

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Journal of Thermal Science 2004年第2期13卷 155-162页

作者： Sui Lin Zheng Jiang Department of Mechanical and Industrial Engineering Concordia University Montreal Canada Flomerics Inc. Southborough USA

The purpose of the paper is to establish a theory of the constant heat flux ratio across the frozen layer based on the dimensional analysis of the system equations describing the freezing processes. An analytical model is then developed, utilizing this theory, for solving the planar, cylindrical and spherical freezing problems with both inward and outward freezing. As there is no exact solution available for the cylindrical and spherical freezing processes, the temperature distribution in the planar solidification obtained from the model is compared with the exact solution. They are in excellent agreement. For the cylindrical and spherical freezing, the complete inward solidification times calculated by the model are compared with those obtained from references. The results are in good agreement. The great advantage of the proposed model is its simplicity and is sufficiently accurate for most practical

关键词： analytical planar cylindrical spherical solidification theory constant heat flux ratio.

Small interplanetary magnetic flux rope

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Science China(Technological Sciences) 2020年第2期63卷 183-194页

作者： FENG HengQiang ZHAO GuoQing WANG JieMin Institute of Space Physics Luoyang Normal UniversityLuoyang 471934China Henan Key Laboratory of Electromagnetic Transformation and Detection Luoyang Normal UniversityLuoyang 471934China

Small interplanetary magnetic flux ropes(SIMFRs) are often detected by space satellites in the interplanetary space near 1 *** ropes can be fitted by a cylindrically symmetric magnetic model. The durations of SIMFRs are usually 700 km/s). Some SIMFRs demonstrate abnormal heavy ion compositions, such as abnormally high He abundance, abnormally high average iron ionization, and enhanced O7+abundance. These SIMFRs originate from remarkably hot coronal origins. Approximately 74.5% SIMFRs exhibit counterstreaming suprathermal electron signatures. Given their flux rope configuration, SIMFRs are potentially more effective for substorms. SIMFRs and magnetic clouds have many similar observational properties but also show some different *** similar properties may indicate that SIMFRs are the interplanetary counterparts of small coronal mass ejections. Some direct bodies of evidence have confirmed that several SIMFRs are interplanetary counterparts of CMEs. However, their different properties may imply that some SIMFRs have interplanetary origins. Therefore, one of the main aims of future research on SIMFRs is to determine whether SIMFRs originate from two different sources, that is, some events are formed in the solar coronal atmosphere, whereas others originate from the interplanetary space. Finally, in this paper, we offer some prospects that should be addressed in the future.

关键词： magnetic flux ropes magnetic cloud coronal mass ejection heliospheric current sheet

Effects of silicon addition on optical properties of mould flux with iron oxide and estimation of apparent thermal conductivity of flux

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Journal of Iron and Steel Research International 2019年第4期26卷 365-373页

作者： Rie Endo Yo Kan Takashi Watanabe Miyuki Hayashi Masahiro Susa Department of Materials Science and Engineering Tokyo Institute of TechnologyTokyo 152-8552Japan Department of Metallurgy and Ceramics Science Tokyo Institute of TechnologyTokyo 152-8552Japan

Mould flux with high absorptivity had been obtained in the reduction process of mould flux by *** further utilisation of the mould flux with high absorptivity,the effect of silicon addition on the optical property has been *** synthesised mould flux powder with iron oxide was melted with the addition of silicon powder at 1703 K followed by quenching,thus forming a glassy *** 5-30-min reduction,the samples exhibited black opaque ***,the samples that were reduced for 45-60 min had a bluish grey *** iron-based particles dispersed in the samples were micrometre order in *** determine the effect of iron particles on the optical properties of the sample,extinction,scattering and absorption efficiencies were calculated according to Mie *** showed that both scattering on the iron particle and absorption by iron effectively increase the extinction efficiency in the mould ***,the silicon particle in the flux has large scattering *** black opaque colour is contributed by the existence of silicon and iron *** apparent thermal conductivity was calculated for the solid *** also indicated that the entire glassy mould flux would effectively work for mild cooling in a continuous casting process owing to high absorptivity and small thermal conductivity.

关键词： Mould flux Reduction Iron oxide Thermal conductivity Optical property

Use of improved cold-finger technique to assess effects of basicity on heat transfer through solidified mold flux

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Journal of Iron and Steel Research International 2019年第4期26卷 393-402页

作者： Karina Lara Santos Assis Petrus Christiaan Pistorius Department of Materials Science and Engineering Center for Iron and Steelmaking ResearchCarnegie Mellon UniversityPittsburgh 15213PAUSA

Cold-finger measurements were used to estimate the contact resistance and average thermal conductivity of mold flux films solidified on a water-cooled copper *** industrial mold fluxes,with basicities from low to high,were *** steady-state rate of convective heat transfer between the solid film and liquid flux was compared with calculations based on natural convection correlations;the comparison indicates that the surface of the solid film(in contact with molten flux)is approximately at its solidus *** roughness of the mold flux film in contact with copper was larger for films grown from higher-temperature mold flux and for higher-basicity mold *** glassy(low-basicity)film had an estimated thermal conductivity of 1.1 W/(m K).The crystalline or partially crystalline films had higher estimated thermal conductivities of 2.2-3.2 W/(m K).The measured values of thermal resistance were extrapolated to typical mold flux film thicknesses for industrial conditions;the extrapolations confirmed that the high contact resistance of higher-basicity mold fluxes can yield higher thermal resistances than the low-basicity *** morphology of the rough interface of higherbasicity mold flux films that gives the higher contact resistance is consistent with that observed in previous work and appears not to be directly related to crystallization.

关键词： Mold flux Heat transfer Conduction Contact resistance-Cold-finger technique