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An oscillation-free Hermite WENO scheme for hyperbolic conservation laws

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Science China Mathematics 2024年第2期67卷 431-454页

作者： Zhuang Zhao Jianxian qiu School of Mathematical Sciences and Institute of Natural Sciences Shanghai Jiao Tong UniversityShanghai 200240China School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling and High-Performance Scientific Computing Xiamen UniversityXiamen 361005China

In this paper, the sixth-order oscillation-free Hermite weighted essentially non-oscillatory (OFHWENO) scheme is proposed for hyperbolic conservation laws on structured meshes, where the zeroth- andfirst-order moments are the variables for the governing equations. The main difference from other HWENOschemes existing in the literature is that we add high-order numerical damping terms in the first-order momentequations to control spurious oscillations for the OF-HWENO scheme. The OF-HWENO scheme not only canachieve the designed optimal numerical order, but also can be easily implemented as we use only one set ofstencils in the reconstruction procedure and the same reconstructed polynomials are applied for the zeroth- andfirst-order moment equations. In order to obtain the adaptive order resolution when facing discontinuities, atransition polynomial is added in the reconstruction, where the associated linear weights can also be any positivenumbers as long as their summation equals one. In addition, the OF-HWENO scheme still keeps compactnessas only immediate neighbor values are needed in the space discretization. Some benchmark numerical tests areperformed to illustrate the high-order accuracy, high resolution and robustness of the proposed scheme.

关键词： Hermite WENO scheme hyperbolic conservation laws oscillation-free adaptive order discontinuous Galerkin method

dimension by dimension Finite Volume HWENO Method for Hyperbolic Conservation Laws

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Communications on Applied Mathematics and Computation 2024年第1期6卷 605-624页

作者： Feng Zheng Jianxian qiu College of Mathematics and Statistics Fujian Normal UniversityFuzhou350117FujianChina School of Mathematical Sciences and Fujian Provincial Key Laboratory of Mathematical Modeling&High-Performance Scientific Computing Xiamen UniversityXiamen361005FujianChina

In this paper,we propose a finite volume Hermite weighted essentially non-oscillatory(HWENO)method based on the dimension by dimension framework to solve hyperbolic conservation *** can maintain the high accuracy in the smooth region and obtain the high resolution solution when the discontinuity appears,and it is compact which will be good for giving the numerical boundary ***,it avoids complicated least square procedure when we implement the genuine two dimensional(2d)finite volume HWENO reconstruction,and it can be regarded as a generalization of the one dimensional(1d)HWENO *** numerical tests are performed to verify the high resolution and high accuracy of the scheme.

关键词： Finite volume dimension by dimension HWENO Hyperbolic conservation laws

Nitrogen availability mediates the effects of roots and mycorrhizal fungi on soil organic carbon decomposition:A meta-analysis

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Pedosphere 2024年第2期34卷 289-296页

作者： Tongshuo BAI Yunpeng qiu Shuijin HU Ecosystem Ecology Laboratory College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China department of Entomology&Plant Pathology North Carolina State UniversityRaleigh NC 27695USA

Plant roots and their associated mycorrhizal fungi critically mediate the decomposition of soil organic carbon(C),but the general patterns of their impacts over a broad geographical range and the primary mediating factors remain *** on a synthesis of 596 paired observations from both field and greenhouse experiments,we found that living roots and/or mycorrhizal fungi increased organic C decomposition by 30.9%,but low soil nitrogen(N)availability(i.e.,high soil C:N ratio)critically mitigated this promotion *** addition,the positive effects of living roots and/or mycorrhizal fungi on organic C decomposition were higher under herbaceous and leguminous plants than under woody and non-leguminous plants,***,there was no significant difference between arbuscular mycorrhizal fungi and ectomycorrhizal fungi in their effects on organic C ***,roots and/or mycorrhizal fungi significantly enhanced the decomposition of leaf litter but not root *** findings advance our understanding of how roots and their symbiotic fungi modulate soil C dynamics in the rhizosphere or mycorrhizosphere and may help improve predictions of soil global C balance under a changing climate.

关键词： arbuscular mycorrhizal fungi ectomycorrhizal fungi leaf litter leguminous plant mycorhizosphere rhizosphere root litter soil C:N ratio

Asymmetric dark matter and Sommerfeld enhancement

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Communications in Theoretical Physics 2024年第8期76卷 120-125页

作者： Sujuan qiu Hoernisa Iminniyaz Wensheng Huo School of Physics Science and Technology Xinjiang University

We study the relic density of asymmetric dark matter with long-range interactions by considering the Sommerfeld effect. We find that the annihilation cross section of asymmetric dark matter is enhanced by the Sommerfeld effect and thus the relic density is decreased. Then we use the Planck data to constrain the asymmetry factor, coupling, and to derive the upper bounds on the dark matter mass in s-wave and p-wave annihilation cases.

关键词： asymmetric dark matter relic density Sommerfeld enhancement

decouple charge transfer reactions in the Li-ion battery

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Journal of Energy Chemistry 2024年第5期92卷 759-798页

作者： Yuxuan Bai qiu-An Huang Kai Wu Jiujun Zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghai 200444China Ningde Contemporary Innovation Laboratory Contemporary Amperex Technology Co.LimitedNingde 352100FujianChina

In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charging,and high safety,an insight into charge transfer reactions is *** electrochemical impedance spectroscopy(EIS)is regarded as a powerful diagnosis tool,it is not a direct but an indirect *** respect to this,some critical questions need to be answered:(i)why EIS can reflect the kinetics of charge transfer reactions;(ii)what the inherent logical relationship between impedance models under different physical scenes is;(iii)how charge transfer reactions compete with each other at multiple *** work aims at answering these questions via developing a theory framework so as to mitigate the blindness and uncertainty in unveiling charge transfer reactions in *** systematically answer the above questions,this article is organized into a three-in-one(review,tutorial,and research)type and the following contributions are made:(i)a brief review is given for impedance model development of the LIBs over the past half century;(ii)an open source code toolbox is developed based on the unified impedance model;(iii)the competive mechanisms of charge transfer reactions are unveiled based on the developed EIS-Toolbox@*** work not only clarifies theoretical fundamentals,but also provides an easy-to-use open source code for EIS-Toolbox@LIB to optimize fast charge/discharge,mitigate cycle aging,and improve energy/power density.

关键词： Electrochemical impedance spectroscopy Unified impedance model Charge transfer reactions Solid/electrolyte diffusion Porous electrode EIS-Toolbox@LIB

Fuzzy-Model-Based Finite Frequency Fault detection Filtering design for Two-dimensional Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第10期11卷 2099-2110页

作者： Meng Wang Huaicheng Yan Jianbin qiu Wenqiang Ji Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationSchool of Information Science and EngineeringEast China University of Science and TechnologyShanghai 200237China Research Institute of Intelligent Control and Systems School of AstronauticsHarbin Institute of TechnologyHarbin 150080China School of Artificial Intelligence Hebei University of TechnologyTianjin 300401China

This article studies the fault detection filtering design problem for Roesser type two-dimensional(2-d)nonlinear systems described by uncertain 2-d Takagi-Sugeno(T-S)fuzzy ***,fuzzy Lyapunov functions are constructed and the 2-d Fourier transform is exploited,based on which a finite frequency fault detection filtering design method is proposed such that a residual signal is generated with robustness to external disturbances and sensitivity to *** has been shown that the utilization of available frequency spectrum information of faults and disturbances makes the proposed filtering design method more general and less conservative compared with a conventional nonfrequency based filtering design ***,with the proposed evaluation function and its threshold,a novel mixed finite frequency H_(∞)/H_(-)fault detection algorithm is developed,based on which the fault can be immediately detected once the evaluation function exceeds the ***,it is verified with simulation studies that the proposed method is effective and less conservative than conventional non-frequency and/or common Lyapunov function based filtering design methods.

关键词： Fault diagnosis finite frequency specifications mixed H_(∞)/H_(-)performance two-dimensional nonlinear systems

A new nonfullerene acceptor with an extended π conjugation core enables ternary organic solar cells approaching 19%efficiency

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Nano Research 2024年第5期17卷 4062-4068页

作者： Chunyan Liu Nailiang qiu Zhengjin Li Yan Lu School of Materials Science and Engineering Tianjin Key Laboratory for Photoelectric Materials and DevicesKey Laboratory of Display Materials and Photoelectric DevicesMinistry of EducationTianjin University of TechnologyTianjin 300384China School of Chemistry Chemical Engineering and MaterialsJining UniversityQufu 273155China

In organic solar cells(OSCs),it is an effective way to improve the power conversion efficiency(PCE)by adding a guest component with appropriate absorption and energy levels in the host ***,a new nonfullerene acceptor(NFA)named TBF-2Cl was developed by the strategy of expanding theπconjugated core of 2,2’-(((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b’]dithiophene-2,7-diyl)bis(methaneylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IdT-4Cl)with two benzene *** increase of benzene units,TBF-2Cl exhibits higher lowest unoccupied molecular orbital(LUMO)level of-3.75 eV than that of one benzene unit based NFA IdT-4Cl and fluorene core based NFA F-2Cl,which facilitates enhancing the open-circuit voltage(V_(oc))of ternary ***,TBF-2Cl film shows a medium optical bandgap with the absorption range from 500-800 nm,being well complementary with the wide bandgap polymer donor d18 and narrow bandgap NFA ***,a remarkable PCE of 18.92%with a high short-circuit current density(J_(sc))of 27.40 mA·cm^(-2),a fill factor(FF)of 0.749,especially an outstanding V_(oc) of 0.922 V was achieved for the optimal ternary device based on d18:TBF-2Cl:CH-6F,surpassing the binary counterpart(17.08%).The findings provide insight into the development of new guest acceptors for obtaining more efficient OSCs.

关键词： medium optical bandgap high lowest unoccupied molecular orbital(LUMO)level the third component ternary organic solar cell high open-circuit voltage

Cross-Country Externalities of Trade and FdI Liberalization

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2013年第1期8卷 19-49页

作者： Qing Liu Larry d. qiu School of International Trade and Economics University of International Business and Eco-nomics Beijing 100029 China School of Economics and Finance The University of Hong Kong Hong Kong China

We develop a three-country heterogeneous-firm model and show that FdI liberalization in one foreign country （F1） results in the following：（i） some firms from the home country switch from export to FdI in F1; （ii） skilled labor＇s wage rate drops in the home country; （iii） wage inequality between the skilled and unskilled labor decreases; and （iv） some firms from the home country switch from FdI to export to another foreign country （F2）. The effects from trade liberalization are just the opposite, but the effects from education improvement are qualitatively the same as FdI liberalization. The cross-country externalities work through the domestic labor market.

关键词： export FdI finn heterogeneity cross-country externalities wage in-equality skill training contractual friction

IPR, Trade, FdI, and Technology Transfer

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2014年第4期9卷 529-555页

作者： Tan Li Larry d. qiu Faculty of Business and Economics The University of Hong Kong Hong Kong China

In this survey, we discuss how intellectual property rights （IPR） protection in the South affects trade flows, foreign direct investment （FdI） flows, and technology transfers from the North to the South. We also discuss optimal IPR policies and their effect on innovation. Our discussion covers both theoretical studies and empirical evidence. This survey is both comprehensive and critical. It aims to give readers the current state of IPR and globalization literature. Some issues have been studied more thoroughly, whereas for others the surface has only been scratched upon. This survey gives readers a clearer picture of the literature and may help them find future research topics.

关键词： IPR trade FdI technology transfer