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Pole-Based Approximation of the Fermi-Dirac Function

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chinese Annals of Mathematics,Series B 2009年第6期30卷 729-742页

作者： Lin LIN Jianfeng LU Lexing YING Weinan E dedicated to professor Andrew Majda on the occasion of his 60th birthday

Two approaches for the efficient rational approximation of the Fermi-Dirac function are discussed： one uses the contour integral representation and conformal real〉 ping, and the other is based on a version of the multipole representation of the Fermi-Dirac function that uses only simple poles. Both representations have logarithmic computational complexity. they are of great interest for electronic structure calculations.

关键词： Contour integral Fermi-Dirac function Rational approximation

Ocean-Atmosphere Interaction in the Lifecycle of ENSO:the Coupled Wave Oscillator

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chinese Annals of Mathematics,Series B 2009年第6期30卷 715-728页

作者： Jialin LIN dedicated to professor Andrew Majda on the occasion of his 60th birthday

To explain the oscillatory nature of E1 Nino/Southern Oscillation （ENSO）, many ENSO theories emphasize the free oceanic equatorial waves propagating/reflecting within the Pacific Ocean, or the discharge/recharge of Pacific-basin-averaged ocean heat content. ENSO signals in the Indian and Atlantic oceans are often considered as remote response to the Pacific SST anomaly through atmospheric teleconnections. This study investigates the ENSO life cycle near the equator using long-term observational datasets. Space-time spectral analysis is used to identify and isolate the dominant interannual oceanic and atmospheric wave modes associated with ENSO. Nino3 SST anomaly is utilized as the ENSO index, and lag-correlation/regression are used to construct the composite ENSO life cycle. the propagation, structure and feedback mechanisms of the dominant wave modes are studied in detail. the results show that the dominant oceanic equatorial wave modes associated with ENSO are not free waves, but are two ocean-atmosphere coupled waves including a coupled Kelvin wave and waves are not confined only to the Pacific a coupled equatorial Rossby （ER） wave. these Ocean, but are of planetary scale with zonal wavenumbers 1-2, and propagate all the way around the equator in more than three years, leading to the longer than 3-year period of ENSO. When passing the continents, they become uncoupled atmospheric waves. the coupled Kelvin wave has larger variance than the coupled ER wave, making the total signals dominated by eastward propagation. surface zonal wind stress （x） acts to slow down the waves. the two coupled waves interact with each other through boundary reflection and superposition, and they also interact with an off-equatorial Rossby wave in north Pacific along 15N through boundary reflection and wind stress forcing. the precipitation anomalies of the two coupled waves meet in the eastern Pacific shortly after the SST maximum of ENSO and excite a dry atmospheric Kelvin wave which

关键词： ENSO Ocean-atmosphere interaction Equatorial waves

Approximating Stationary Statistical Properties

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chinese Annals of Mathematics,Series B 2009年第6期30卷 831-844页

作者： Xiaoming WANG dedicated to professor Andrew Majda on the occasion of his 60th birthday with Admiration and Friendship）

It is well-known that physical laws for large chaotic dynamical systems are revealed *** times these statistical properties of the system must be approximated *** main contribution of this manuscript is to provide simple and natural criterions on numerical methods (temporal and spatial discretization) that are able to capture the stationary statistical properties of the underlying dissipative chaotic dynamical systems *** result on temporal approximation is a recent finding of the author,and the result on spatial approximation is a new *** to the infinite Prandtl number model for convection and the barotropic quasi-geostrophic model are also discussed.

关键词： Stationary statistical property Invariant measure Global attractor Dissipative system Time discretization Spatial discretisation Uniformly dissipative scheme Infinite Prandtl number model for convection Barotropic quasi-geostrophic equations

Two-Dimensional Riemann Problems for the Compressible Euler System

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chinese Annals of Mathematics,Series B 2009年第6期30卷 845-858页

作者： Yuxi ZHENG dedicated to professor Andrew Majda for his 60th birthday

Riemann problems for the compressible Euler system in two space dimensions are complicated and difficult,but a viable alternative remains *** author lists merits of one-dimensional Riemann problems and compares them with those for the current two-dimensional Riemann problems,to illustrate their ***-dimensional Riemann problems are approached via the methodology promoted by Andy Majda in the spirits of modern applied mathematics;that is,simplified model is built via asymptotic analysis,numerical simulation and theoretical analysis.A simplified model called the pressure gradient system is derived from the full Euler system via an asymptotic ***-of-the-art numerical methods in numerical simulations are used to discern small-scale structures of the solutions,e.g.,semi-hyperbolic *** methods are used to establish the validity of the structure revealed in the numerical *** entire process,used in many of Majda's programs,is shown here for the two-dimensional Riemann problems for the compressible Euler systems of conservation laws.

关键词： Characteristic decomposition Guderley reflection Hodograph transform Pressure gradient system Self-similar Semi-hyperbolic wave Triple point paradox Riemann problem Riemann variable

Existence of Nonnegative Solutions for a Class of Systems Involving Fractional (p, q)-Laplacian Operators

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chinese Annals of Mathematics,Series B 2018年第2期39卷 357-372页

作者： Yongqiang FU Houwang LI Patrizia PUCCI dedicated to professor Philippe G. Ciarlet on the occasion of his 80th birthday with high feelings of esteem for his notable contributions in mathematics and great affectio

the authors study the following Dirichlet problem of a system involving fractional(p, q)-Laplacian operators:{(-△)_p^su=λa(x)|u|+^(p-2)u+λb(x)|u|^(α-2)|u|~βu+μ(x)/αδ|u|^(γ-2)|v|~δu in Ω,(-△)_p^su=λc(x)|v|+^(q-2)v+λb(x)|u|~α|u|^(β-2)v+μ(x)/βγ|u|~γ|v|^(δ-2)v in Ω,u=v=0 on R^N\Ω where λ > 0 is a real parameter, ? is a bounded domain in RN, with boundary ?? Lipschitz continuous, s ∈(0, 1), 1 the fractional p-Laplacian operator of u and, similarly,(-?)s qv is the fractional q-Laplacian operator of v. Since possibly p = q, the classical definitions of the Nehari manifold for systems and of the Fibering mapping are not suitable. In this paper, the authors modify these definitions to solve the Dirichlet problem above. then, by virtue of the properties of the first eigenvalueλ_1 for a related system, they prove that there exists a positive solution for the problem when λ the modified definitions. Moreover, the authors obtain the bifurcation property when λ→λ_1^-. Finally, thanks to the Picone identity, a nonexistence result is also obtained when λ≥λ_1.

关键词： the Nehari manifold Fractional p-Laplacian Variational methods

A-site Cation Defects(Ba_(0.5)Sr_(0.5))_(1-x)Co_(0.8)Fe_(0.2)O_(3-δ)Perovskites as Active Oxygen Evolution Reaction Catalyst in Alkaline Electrolyte

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chinese Journal of Chemistry 2021年第10期39卷 2692-2698页

作者： Lulu Tang Yifei Rao Lianwei Wei Hui Zheng Huimin Liu Wenhua Zhang Kaibin Tang Department of Chemistry University of Science and Technology of ChinaHefeiAnhui 230026China CAS Key Laboratory of Materials for Energy Conversion Department of Material Science and TechnologyUniversity of Science and Technology of ChinaHefeiAnhui230026 China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefeiAnhui230026 China dedicated to professor Yitai Qian on the occasion of his 80th birthday

Main observation and conclusion Perovskites(Ba_(0.5)Sr_(0.5))_(1-x)Co_(0.8)Fe_(0.2)O_(3-δ)(x=0.02,0.05,0.1 denoted as BSCF-0.98,BSCF-0.95,BSCF-0.9,respectively)with A-site cation defects are synthesized by simple and efficient sol-gel method and are proved to have better OER catalytic effect than the well-known(Ba_(0.5)Sr_(0.5))_(1-x)Co_(0.8)Fe_(0.2)O_(3-δ)(BSCF)***-0.95 exhibits the best OER catalytic activity in the series *** current density of BSCF-0.95 is about 56%higher than that of BSCF oxide at a potential of 1.7 *** experimental studies have shown that compared with BSCF,BSCF-0.95 oxide has a larger electrochemical surface area(ECSA),a higher content of O_(2)^(2–)species related to surface oxygen vacancies,and faster charge transfer rate,which may be the factors for the enhancement of OER *** theoretical calculation results prove that the center positions of the O 2p-band of perovskite with A-site cation defects are closer to the Fermi level than BSCF oxide,which agrees with the OER performance trend of the material.

关键词： Perovskite phases Oxygen evolution reaction Electrochemistry A-site cation defects

professor Delong su:a pioneer in Schistosomiasis Eradication in china

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Protein & Cell 2023年第12期14卷 861-865页

作者： Zhimei Que Zhujun su Yuanyuan Meng Family of professor Delong su Shanghai 200031China Beijing Institutes of Life Science Chinese Academy of SciencesBeijingChina

Delong su(Teh-long su,1906-1985)was an intermationally renowned public health expert,a medical educator and philosopher,and one of the major founders of classic epidemiology in china(Fig.1).He was among the first group of the national distinguished professors and doctoral supervisors appointed since the founding of the People's Republic of *** su served as vice-president of the Shanghai First Medical College and vice-chairman of the National Schistosomiasis Research Council.

关键词： founding Schistosomiasis pioneer

china and Natural Resource Curse in Developing Countries： Empirical Evidence from a Cross-country Study

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china & World Economy 2016年第1期24卷 18-40页

作者： Fubing su Guoxue Wei Ran Tao professor School of Economics Renmin University of China

china＇s rising demand for natural resources and its growing presence in many poor and resource-rich countries have been criticized for promoting neo-colonialism in the 21st century. Using panel data for 135 developing countries from 1995 to 2007, the present paper empirically evaluates the validity of such claims. Our findings do not support the resource curse thesis in the areas of industrialization and economic growth. Moreover, the effect of resources is conditional on the initial quality of political institutions in a country.

关键词： china developing countries economic growth resource curse

Enhanced Heat Transfer with Full Circumferential Ribs in Helical Pipe

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Journal of thermal Science 2002年第3期11卷 241-248页

作者： S.W.Chang L.M.su T.L.Yang Department of Marine Engineering National Kaohsiung Institute of Marine Technology Kaohsiung Taiwan China Associate professor Department of Electrical Engineering Tong Fang College of Technology and Commerce Taiwan China Associate professor and Head of Department Department of Electrical Engineering Fortune Institute of Technology Taiwan China

This paper describes an experimental study of heat transfers in the smooth-walled and rib-roughened helical pipes with reference to the design of enhanced cooling passages in the cylinder head and liner of a marine propulsive diesel engine. the manner in which the repeated ribs modify the forced heat convection in the helical pipe is considered for the case where the flow is turbulent upon entering the coil but laminar in further downstream. A selection of experimental results illustrates the individual and interactive effects of Dean vortices and rib-flows on heat transfer along the inner and outer helixes of coils. the experimental-based observations reveal that the centrifugal force modifies the heat transfer in a manner to generate circumferential heat transfer variation with better cooling performance on the outer edge relative to its inner counterpart even with the agitated flow field caused by the repeated ribs. Heat transfer augmentation factor in the range of 1.3 ~ 3 times of the smooth-walled

关键词： helical pipe heat transfer enhancement.