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High-Order Decoupled and Bound Preserving Local Discontinuous Galerkin Methods for a Class of Chemotaxis Models

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Communications on Applied Mathematics and Computation 2024年第1期6卷 372-398页

作者： Wei zheng Yan Xu School of Mathematical Sciences University of Science and Technology of ChinaHefei230026AnhuiChina

In this paper,we explore bound preserving and high-order accurate local discontinuous Galerkin(LDG)schemes to solve a class of chemotaxis models,including the classical Keller-Segel(KS)model and two other density-dependent *** use the convex splitting method,the variant energy quadratization method,and the scalar auxiliary variable method coupled with the LDG method to construct first-order temporal accurate schemes based on the gradient flow structure of the *** semi-implicit schemes are decoupled,energy stable,and can be extended to high accuracy schemes using the semi-implicit spectral deferred correction *** bound preserving DG discretizations are only worked on explicit time integration methods and are difficult to get high-order *** overcome these difficulties,we use the Lagrange multipliers to enforce the implicit or semi-implicit LDG schemes to satisfy the bound constraints at each time *** bound preserving limiter results in the Karush-Kuhn-Tucker condition,which can be solved by an efficient active set semi-smooth Newton *** numerical experiments illustrate the high-order accuracy and the effect of bound preserving.

关键词： Chemotaxis models Local discontinuous Galerkin(LDG)scheme Convex splitting method Variant energy quadratization method Scalar auxiliary variable method Spectral deferred correction 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

Trace Lasso Regularization for Adaptive Sparse Canonical Correlation Analysis via Manifold Optimization Approach

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Journal of the Operations Research Society of China 2024年第3期12卷 573-599页

作者： Kang-Kang Deng zheng Peng Beijing International Center for Mathematical Research Peking UniversityBeijing100871China School of Mathematics and Computational Science Xiangtan UniversityXiangtan411105China

Canonical correlation analysis(CCA)describes the relationship between two sets of variables by finding a linear combination that maximizes the correlation ***,in high-dimensional settings where the number of variables exceeds sample size,or in the case that the variables are highly correlated,the traditional CCA is no longer *** this paper,a new matrix regularization is introduced,which is an extension of the trace Lasso in the vector *** we propose an adaptive sparse version of CCA(ASCCA)to overcome these disadvantages by utilizing the trace Lasso *** adaptability of ASCCA is that the sparsity regularization of canonical vectors depends on the sample data,which is more realistic in practical *** ASCCA model is further reformulated to an optimization problem on the Riemannian *** we adopt a manifold inexact augmented Lagrangian method to solve the resulting optimization *** performance of the ASCCA model is compared with some existing sparse CCA techniques in different simulation settings and real datasets.

关键词： Canonical correlation analysis Sparsity of canonical vectors Trace Lasso regularization Manifold optimization

Appreciable Enhancement of Photocatalytic Performance for N-doped SrMoO_(4) via the Vapor-thermal Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 24-31页

作者：恽志强戴振翔 ZHU Liwei zheng Ganhong School and Materials Science and Engineering Anhui UniversityHefei 230601China School of Physics and Optoelectronics Engineering Anhui UniversityHefei 230601China

A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal *** photocatalytic degradation ability of all samples was evaluated using methylene blue (MB) as a target *** band gaps of N-doped samples are all higher than that of pristine ones,which is only 3.12 *** specific surface area S_(BET) and pore volume are increased due to the N *** the greater increase of S_(BET),the faster the photodegradation speed of methylene blue on SrMoO_(4).More specifically,the degradation efficiency of MB is improved up to 87%in 100 min.

关键词： SrMoO_(4) photocatalytic property nitrogen element doping

Achieving tunable long persistent luminescence in metal organic halides based on pyridine solvent

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Chinese Chemical Letters 2024年第9期35卷 227-231页

作者： Jun-Ting Mo zheng Wang College of Chemistry and Chemical Engineering Key Laboratory of Chemical Additives for China National Light IndustryShaanxi University of Science and TechnologyXi’an 710021China MOE Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-sen UniversityGuangzhou 510275China

The research of long persistent luminescence(LPL)materials has yield brilliant results in many ***,the efforts are still needed for the regulation of the LPL *** this work,a series of LPL metal organic halides with rich halogen-bond interactions,Py-CdX_(2)(X=Cl,Br,I)were synthesized through self-assembly by Cd X_(2)and pyridine *** steady-state emission redshifted and phosphorescence lifetime declined as the halogen atoms are *** halides exhibit adjustable emission from blue to green and multiple phosphorescence from green to yellow at room temperature by changing the excitation ***,Py-CdX_(2)can emit the visible color-tunable LPL from green to yellow after removing different excitation sources at ambient *** the results of theoretical calculation and experimental analysis,it is found that heavy atom effect and the rich intermolecular halogen bond help realize LPL and multiple triplet states originated from the pyridine ring and the halogens.

关键词： Metal organic halide Heavy atom effect Halogen bond Tunable long persistent luminescence Anti-counterfeiting

Multiscale engineered hydrogel for solar evaporation with enhanced water transport and purification

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Science China Materials 2024年第8期67卷 2709-2710页

作者： Mingzhan Wang Ronghui Wu Shuang zheng Pritzker School of Molecular Engineering University of ChicagoChicagoIL 60637USA Department of Civil Engineering The University of Hong KongHong Kong 999077China

Solar evaporation is emerging as a powerful solution to alleviate the global water shortage *** a recent work published in Nature Water,Liangti Qu and coworkers[1]report a facile method of preparing a graphene/alginate hydrogel(GAH),which not only possesses nearly total rejections to salts,volatile and non-volatile organic compounds,but also exhibits excellent antifouling properties to bacteria and *** the perspective of chemistry,these impressive properties originate from the systematic engineering of the GAH,ranging from the molecular scale to the macroscopic scale.

关键词： volatile hydrogel preparing

Selective N-Methylation of N-Methylaniline with CO_(2) and H_(2) over Cu/In_(2)O_(3. Catalyst

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Chinese Journal of Chemistry 2024年第3期42卷 276-282页

作者： Huan zheng Bo Qian Lin He State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouGansu730000 China University of Chinese Academy of Sciences Beijing100049 China

N-Methylation of amines with CO_(2) and H2 is a potential approach for CO_(2) utilization because N-methylated amines can be used as solvents and organic intermediates. In_(2)O_(3.-supported Cu (Cu/In_(2)O_(3.) acts as an effective heterogeneous catalyst for N-methylation reaction of N-methylaniline (MA) with CO_(2) and H_(2),showing higher N,N-dimethylaniline (DMA) selectivity than other supported Cu catalysts. On one hand,the dispersion of Cu can be improved by the defective In_(2)O_(3. support. On the other hand,In_(2)O_(3. support is active in the dissociative adsorption of CO_(2) through C—O bond breaking. In addition,the H_(2) dissociation ability of In_(2)O_(3. can also be enhanced by Cu. The combination of Cu and In_(2)O_(3. is effective in the activation of CO_(2),the adsorption of intermediate N-methylformanilide (MFA),the hydrogenation of MFA to DMA and the prohibition of C—N bond cleavage side reactions,thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

关键词： N-Methylation CO_(2) Cu/In_(2)O_(3. Supported catalysts Heterogeneous catalysis

Stereochemical editing:Catalytic racemization of secondary alcohols and amines

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Chinese Chemical Letters 2024年第5期35卷 17-31页

作者： Jun Zhang Zhiyao zheng Can Zhu Department of Chemistry Fudan UniversityShanghai 200438China Department of Organic Chemistry Arrhenius LaboratoryStockholm UniversityStockholm 10691Sweden

Chiral alcohols and amines are important structural units widely existing in pharmaceuticals,agrochemicals,and food *** kinetic resolution(DKR)is an efficient strategy to deliver optically active alcohols and amines from their *** the development of DKR method,racemization catalyst plays as a crucial element with the requirement of compatibility with the kinetic resolution(KR)*** this paper,recent advance in the catalytic racemization of secondary alcohols and amines is summarized based on different types of racemizing intermediates,which are redox racemization via ketone/imine intermediates,racemization via radical intermediates,and racemization via carbocation *** racemization of secondary alcohols and amines is also enclosed.

关键词： Racemization Secondary alcohols Amines Kinetic resolution Dynamic kinetic resolution

Reliability ensemble averaging reduces surface wind speed projection uncertainties in the 21st century over China

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Advances in Climate Change Research 2024年第2期15卷 222-229页

作者： zheng-Tai ZHANG Chang-Ai XU Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

Accurate prediction of future surface wind speed(SWS)changes is the basis of scientific planning for wind *** studies have projected SWS changes in the 21st century over China on the basis of the multi-model ensemble(MME)of the 6th Coupled Model Intercomparison Project(CMIP6).However,the simulation capability for SWS varies greatly in CMIP6 multi-models,so the MME results still have large *** this study,we used the reliability ensemble averaging(REA)method to assign each model different weights according to their performances in simulating historical SWS changes and project the SWS under different shared socioeconomic pathways(SSPs)in *** results indicate that REA considerably improves the SWS simulation capacity of CMIP6,eliminating the overestimation of SWS by the MME and increasing the simulation capacity of spatial *** spatial correlations with observations increased from 0.56 for the MME to 0.85 for ***,REA could eliminate the overestimation of the SWS by 3.%in *** for southeastern China,the SWS generally decreases over China in the near term(2020-2049)and later term(2070-2099),particularly under high-emission *** SWS reduction projected by REA is twice as high as that by the MME in the near term,reaching-4%to-3..REA predicts a larger area of increased SWS in the later term,which expands from southeastern China to eastern *** study helps to reduce the projected SWS uncertainties.

关键词： Surface wind speed Uncertainty Multi-model ensemble Reliability ensemble averaging CMIP6