检索结果-南通市图书馆

Surface engineering based on in situ electro-polymerization to boost the initial Coulombic efficiency of hard carbon anode for sodium-ion battery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2022年第5期41卷 1616-1625页

作者： Cheng-xin Yu Yu Li Zhao-Hua Wang xin-Ran Wang Ying Bai chuan Wu Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing 314019China

Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of *** this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.

关键词： Sodium-ion battery Hard carbon Initial Coulombic efficiency Solid electrolyte interface Surface modification Ester electrolyte

Recent progress on DNA block copolymer

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2017年第9期28卷 1822-1828页

作者： Gaifang Pan xin Jin Quanbing Mou chuan Zhang School of Chemistry and Chemical Engineering State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong University

DNA has gained great attention because of its unique structure,excellent molecular recognition property,and biological *** married with versatile synthetic polymers,the DNA conjugated polymer hybrids,known as DNA block copolymers（DBCs）,have been launched and well developed for the syntheses of new materials and nanostructures with different functions in the past several *** to conventional synthetic block copolymers,using DNA as a building block provides several advantages over other polymer candidates,such as molecular recognition,programmable self-assembly,biocompatibility,and sequence-encoded *** this review,recent developments in this area will be summarized and meaningful breakthroughs will be *** will discuss representative examples of recent progress in the syntheses,structure manipulations,and applications of DBCs.

关键词： DNA block copolymer Self-assembly Nanostructure Hybrid material Micelle

Stochastic Multiresonance Induced by an Optimal Noise Pulse Interval Due to Hopping of Energy Levels

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第7期18卷 870-873页

作者： ZHANG Ji-Qian xin hou-Wen Department of Chemical Physics University of Science and Technology of ChinaHefei 230026

An interesting phenomenon,called the Stochastic multiresonance(SMR),induced by the variation of the noise pulse interval,is described and the formative mechanism of SMR is investigated by using the concept of hopping between different energy ***,the SMR can be realized by choosing the optimal noise pulse interval or selecting the appropriate noise intensity.

关键词： resonance SMR Optimal

Entanglement and Energy for Vibrationally Localized States in Molecule CS2

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第3期28卷 295-298,I0001页

作者： Zi-xin Yang xing Shen Xi-wen hou Department of Physics Huazhong Normal University Wuhan 430079 China

The dynamics of quantum entanglement described by the yon Neumann entropy is studied for the localized states of Fermi-resonance coupling vibrations in molecule CS2, where the interacting energy between the stretching and the bending modes is considered to establish a connection between entanglement and energy. It is shown that entanglement reveals dominant anti-correlation with the interacting energy for the stretch-localized state, while that exhibits dominantly positive correlation for the bend-localized state. The entanglement and the energy for the dislocalized states are discussed as well. Those are useful for molecular quantum computing and quantum information in high dimensional states.

关键词： Entanglement Quantum entropy Vibrational analysis

NUMERICAL SIMULATIONS OF 2D PERIODIC UNSTEADY CAVITATING FLOWS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第3期18卷 341-344页

作者： WU Lei LU chuan-jing LI Jie CHEN xin Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China

A two-phase mixture model was established to study unsteady cavitating flows. A local compressible system of equations was derived by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for solving the variable-density Navier-Stokes equations of cavitating flow problem was put forward. The numerical results for unsteady characteristics of cavitating flows on a 2D NACA hydrofoil coincide well with experimental data.

关键词： unsteady cavitating flow variable-density Navier-Stokes equations periodic cavity break-off and shedding hydrofoil

Ambarzumyan's Theorem for the Dirac Operator on Equilateral Tree Graphs

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 568-576页

作者： Dong-Jie WU xin-Jian XU chuan-Fu YANG Department of Mathematics School of Mathematics and StatisticsNanjing University of Science and TechnologyNanjing 210094China

The classical Ambarzumyan’s theorem states that if the Neumann eigenvalues of the Sturm-Liouville operator-d^(2)/dx^(2)+q with an integrable real-valued potential q on[0,π] are {n^(2):n≥0},then q=0 for almost all x∈[0,π].In this work,the classical Ambarzumyan’s theorem is extended to the Dirac operator on equilateral tree *** prove that if the spectrum of the Dirac operator on graphs coincides with the unperturbed case,then the potential is identically zero.

关键词： dirac operator quantum graph Ambarzumyan’s theorem inverse spectral problem

Constitutive modelling of fabric effect on sand liquefaction

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第4期15卷 926-936页

作者： Zhiwei Gao Dechun Lu Yue hou xin Li James Watt School of Engineering University of GlasgowGlasgowG128QQUK Institute of Geotechnical and Underground Engineering Beijing University of TechnologyBeijing100124China Beijing Key Laboratory of Traffic Engineering Beijing University of TechnologyBeijingChina

Sand liquefaction under static and dynamic loading can cause failure of embankments,slopes,bridges and other important *** liquefaction in the seabed can also cause submarine landslides and *** anisotropy related to the internal soil structure such as particle orientation,force network and void space is found to have profound influence on sand liquefaction.A constitutive model accounting for the effect of anisotropy on sand liquefaction is *** of fabric anisotropy during loading is considered according to the anisotropic critical state theory for *** model has been validated by extensive test results on Toyoura sand with different initial densities and stress *** effect of sample preparation method on sand liquefaction is qualitatively *** model has been used to investigate the response of a sand ground under earthquake *** is shown that sand with horizontal bedding plane has the highest resistance to liquefaction when the sand deposit is anisotropic,which is consistent with the centrifuge test *** initial degree of fabric anisotropy has a more significant influence on the liquefaction *** with more anisotropic fabric that can be caused by previous loading history or compaction methods has lower liquefaction resistance.

关键词： Sand Anisotropy Liquefaction Finite element modelling Constitutive model

APPLICATION OF QUADRATIC AND CUBIC TURBULENCE MODELS ON CAVITATING FLOWS AROUND SUBMERGED OBJECTS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第6期24卷 823-833页

作者： CHEN Ying LU chuan-jing CAO Jia-yi CHEN xin Department of Engineering Mechanics Shanghai Jiao Tong University Department of Engineering Mechanics and State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University

Quadratic and cubic Non-Linear Eddy-Viscosity Models （NLEVMs） at low Reynolds number （Re） correction were introduced into the present Computational Fluid Dynamics （CFD） framework, to provide better numerical treatment about the anisotropic turbulence stress in cavitating flows, which have large density ratio and large-scaled swirling flow structures. The applications of these NLEVMs were carried out through a self-developed cavitation code, coupled with a cavitation model based on the transport equation of liquid phase. These NLEVMs were firstly validated by the benchmark of disk supercavity, and found able to obtain more accurate capture of the hydrodynamic properties than the linear models. One of such models was further applied on the cavitation problem of submerged vehicles. Ultimately, the supercavitating flows around an especially designed underwater vehicle were predicted using the cubic k - e turbulence model, and its cavitation behaviors were studied.

关键词： cavitating flow Non-Linear Eddy-Viscosity Model (NLEVM) submerged object cavitation model

Moduli Space of IIB Superstring and SUYM in AdS5 × S^5

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第2期45卷 301-314页

作者： hou Bo-Yu hou Bo-Yuan WANG Xiao-Hui XIONG chuan-Hua YUE Rui-Hong Institute of Modern Physics Northwest University Xi＇an 710069 China Graduate School the Chinese Academy of Sciences Beijing 100039 China

This paper consists of two parts. In part I, we interpret the hidden symmetry of the moduli space of lib superstring on AdS5× S^5 in terms of the chiral embedding in AdS5, which turns out to be the CP^3 conformal affine Toda model. We review how the position μ of poles in the Riemann-Hilbert formulation of dressing transformation and the value of loop parameter μ in the vertex operator of affine algebra determine the moduli space of the soliton solutions, which describes the moduli space of the Green-Schwarz superstring. We show also how this affine SU（4） symmetry affinizes the conformal symmetry in the twistor space, and how a soliton string corresponds to a Robinson congruence with twist and dilation spin coefficients μ of twistor. In part Ⅱ by extending the dressing symmetric *** of lib string in AdS5×S^5 to the D3 brane, we find a gauged WZW aztion of Higgs Yang-Mills field including the 2-cocycle of axially anomaly. The left and right twistor structures of left and right a-planes glue into an ambitwistor. The symmetry group of Nahm equations is centrally extended to an affine group, thus we explain why the spectral curve is given by affine Toda.

关键词： AdS/CFT correspondence Green-Schwarz superstring affine Toda