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HERMITE WENO SCHEMES WITH LAX-WENDROFF TYPE TIME DISCRETIZATIONS FOR HAMILTON-JACOBI EQUATIONS

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Journal of Computational Mathematics 2007年第2期25卷 131-144页

作者： Jianxian qiu Department of Mathematics Nanjing University Nanjing 210093 China

In this paper, we use Hermite weighted essentially non-oscillatory （HWENO） schemes with a Lax-Wendroff time discretization procedure, termed HWENO-LW schemes, to solve Hamilton-Jacobi equations. The idea of the reconstruction in the HWENO schemes comes from the original WENO schemes, however both the function and its first derivative values are evolved in time and are used in the reconstruction. One major advantage of HWENO schemes is its compactness in the reconstruction. We explore the possibility in avoiding the nonlinear weights for part of the procedure, hence reducing the cost but still maintaining non-oscillatory properties for problems with strong discontinuous derivative. As a result, comparing with HWENO with Runge-Kutta time discretizations schemes （HWENO-RK） of qiu and Shu [19] for Hamilton-Jacobi equations, the major advantages of HWENO-LW schemes are their saving of computational cost and their compactness in the reconstruction. Extensive numerical experiments are performed to illustrate the capability of the method.

关键词： WENO scheme Hermite interpolation Hamilton-Jacobi equation Lax-Wendroff type time discretization High order accuracy.

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鄱阳湖地区湿地保护现状及其主要影响因素

东北林业大学学报 2025年第2期53卷 122-126页

作者：邱万保赵英杰新疆政法学院图木舒克832003 东北林业大学

在鄱阳湖区域,选取鄱阳湖国家级自然保护区、鄱阳湖南矶湿地国家级自然保护区、都昌候鸟省级自然保护区、东鄱阳湖国家湿地公园、都昌北鄱阳湖湿省级地公园5个典型湿地保护地为研究地;采用问卷调查方法,选择研究地的管理人员、技术人员... 详细信息

在鄱阳湖区域,选取鄱阳湖国家级自然保护区、鄱阳湖南矶湿地国家级自然保护区、都昌候鸟省级自然保护区、东鄱阳湖国家湿地公园、都昌北鄱阳湖湿省级地公园5个典型湿地保护地为研究地;采用问卷调查方法,选择研究地的管理人员、技术人员、野外工作人员、其他工作人员,调查研究地的资源保护与破坏现状、湿地保护地存在的问题、保护地存在问题的成因、对现实问题的解决方式及建议,问卷有效率93.64%。依据调查数据,分析鄱阳湖地区湿地保护现状及其主要影响因素。调查结果表明:①鄱阳湖湿地保护现状较为理想,湿地资源得到了合理的保护和利用。在受访者中,83.50%工作人员认为湿地水鸟种类增加或维持不变、74.76%工作人员认为湿地水鸟数量增加或维持不变、73.78%工作人员认为湿地水鸟已经达到或基本达到最适数量、63.11%工作人员认为湿地水鸟繁殖能力增加或不变。②各保护地的湿地保护现状差异明显,在受访者中,62.38%工作人员认为鄱阳湖地区湿地保护过程中存在不利影响,主要集中在生态旅游、水量减少、湿地污染、湿地占用等方面。80.58%工作人员认为湿地生态旅游存在负面影响,其中63.10%工作人员认为生态旅游存在严重影响;33.01%工作人员认为湿地保护地的不利基础设施建设存在严重影响或一般影响;82.52%工作人员认为湿地水量减少是湿地保护面临的问题之一;53.40%工作人员认为湿地污染是湿地保护面临的问题之一。③鄱阳湖地区湿地破坏的成因包括鄱阳湖地区湿地保护法规不完善、湿地保护的政府间联动机制不健全、湿地工作人员构成不合理。④改进措施,完善地方湿地立法、政府间部门联动机制、地区人才培养机制及相关政策。

关键词：鄱阳湖湿地保护自然保护区

A direct-variance-analysis method for generalized stochastic eigenvalue problem based on matrix perturbation theory

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Science China(Technological Sciences) 2014年第6期57卷 1238-1248页

作者： qiu ZhiPing qiu HeChen Institute of Solid Mechanics Beihang University

It has been extensively recognized that the engineering structures are becoming increasingly precise and complex,which makes the requirements of design and analysis more and more *** the uncertainty effects are indispensable during the process of product ***,iterative calculations,which are usually unaffordable in calculative efforts,are unavoidable if we want to achieve the best *** uncertainty effects into consideration,matrix perturbation methodpermits quick sensitivity analysis and structural dynamic re-analysis,it can also overcome the difficulties in computational *** to the situations above,matrix perturbation method has been investigated by researchers worldwide ***,in the existing matrix perturbation methods,correlation coefficient matrix of random structural parameters,which is barely achievable in engineering practice,has to be given or to be assumed during the computational *** has become the bottleneck of application for matrix perturbation *** this paper,we aim to develop an executable approach,which contributes to the application of matrix perturbation *** the present research,the first-order perturbation of structural vibration eigenvalues and eigenvectors is derived on the basis of the matrix perturbation theory when structural parameters such as stiffness and mass have *** the first-order perturbation of structural vibration eigenvalues and eigenvectors with the probability theory,the variance of structural random eigenvalue is derived from the perturbation of stiffness matrix,the perturbation of mass matrix and the eigenvector of baseline-structure *** the Direct-VarianceAnalysis(DVA)method is developed to assess the variation range of the structural random eigenvalues without correlation coefficient matrix being *** feasibility of the DVA method is verified with two numerical examples(one is trusssystem and the other is wing struct

关键词： matrix perturbation theory generalized stochastic eigenvalue problem structure with random parameter direct variance analysis

Electrocatalytic cleavage of a lignin β-O-4 model compound and coupling with nitrogen-containing aromatics using Prussian blue analogue-derived nickel–cobalt spinel

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Journal of Energy Chemistry 2025年第01期 628-636页

作者： Yi Qi Xueying Chen Bowen Liu Xuliang Lin Xueqing qiu Yanlin Qin Guangdong Provincial Key Laboratory of Plant Resources Biorefinery School of Chemical Engineering and Light Industry Guangdong University of Technology Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Guangdong Basic Research Center of Excellence for Ecological Security and Green Development Guangdong University of Technology

Electrochemical conversion of lignin for the production of high-value heterocyclic aromatic compounds has great *** demonstrate the targeted synthesis and cation modulation of NiCo2O4spinel nanoboxes,synthesized via cation exchange and calcination *** catalysts exhibit excellent efficacy in the electrocatalytic conversion of lignin model compounds,specifically 2-phenoxy-1-phenylethanol,into nitrogen-containing aromatics,achieving high conversion rates and *** catalysts were synthesized via a cation exchange and calcination oxidation process,using Prussian blue nanocubes as *** porous architecture and polymetallic composition of the NiCo2O4spinel demonstrated superior performance in electrocatalytic oxidative coupling,achieving a 99.2 wt%conversion rate of the 2-phenoxy-1-phenylethanol with selectivities of 37.5 wt%for quinoline derivatives and 31.5 wt%for *** innovations include the development of a sustainable one-pot synthesis method for quinoline derivatives,the elucidation of a multistage reaction pathway involving CAO bond cleavage,hydroxyaldol condensation,and CAN bond formation,and a deeper mechanistic understanding derived from DFT *** work establishes a new strategy for lignin valorization,offering a sustainable route to produce high-value nitrogen-containing aromatics from renewable biomass under mild conditions,without the need for additional reagents.

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A Rigidity Result of Spacelike Self-Shrinkers in Pseudo-Euclidean Spaces

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Chinese Annals of Mathematics,Series B 2021年第2期42卷 291-296页

作者： Hongbing qiu School of Mathematics and Statistics Wuhan UniversityWuhan 430072China Hubei Key Laboratory of Computational Science Wuhan UniversityWuhan 430072China

In this paper, the author proves that the spacelike self-shrinker which is closed with respect to the Euclidean topology must be flat under a growth condition on the mean curvature by using the Omori-Yau maximum princ... 详细信息

关键词： Self-Shrinker Rigidity Omori-Yau maximum principle Pseudo-distance

Science communication in China: a critical component of the global science powerhouse

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National Science Review 2020年第4期7卷 824-829页

作者： Jane qiu Writes for NSR

China has attached a great significance to bringing science to the public—known as kepu(, ‘science popularization’) or kexue chuanbo(, ‘science dissemination’)—in recent years, partly in response to its unprecedented push for innovation in science and technology. In 2018, it spent 16 billion yuan(US$2.3 billion) on such endeavours, nearly 80% of which was government funding, according to a survey conducted by the Ministry of Science and Technology. With one science-education venue for every million people, approximately 76 million visits

关键词： a critical component of the global science powerhouse Science communication in China

Hierarchical self-assembly: when sugar meets amino acid

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Science China Chemistry 2016年第12期59卷 1621-1622页

作者： Huibin qiu School of Physical Science and Technology ShanghaiTech University

Life is an extremely delicate self-assembly system, where a rich array of small molecules, macromolecules and other entities associate and organize in an intrinsically diverse and precise manner. During the past few decades, scientists have devoted enormous efforts to fabricate functional materials, including the interesting self-assembled molecular devices that recently crowned with the 2016 Nobel Chemistry Prize, by self-assembly of natural and synthetic molecules/mac- romolecules. Nevertheless, it still remains an incredibly big challenge to approach the elegance of life self-assembly, predominantly as a consequence of limited diversity and accuracy of chemistry, structure, and supramolecular asso- ciation of the building blocks.

关键词： when sugar meets amino acid Figure Hierarchical self-assembly

黑磷/黑砷异质结纳米器件热电性质应力调控研究

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原子与分子物理学报 2025年第1期42卷 69-74页

作者：戎杙邱乙峰张蓓新疆大学物理科学与技术学院乌鲁木齐830046

探索新型高性能低维热电纳米材料已成为国家重大发展策略.论文采用密度泛函理论结合非平衡态格林函数方法研究了由黑磷、黑砷纳米带构建异质结构在2%、4%、6%和8%四种拉伸应变作用下热电性能调控机理.研究结果表明,6%拉伸应变较其他情形... 详细信息

探索新型高性能低维热电纳米材料已成为国家重大发展策略.论文采用密度泛函理论结合非平衡态格林函数方法研究了由黑磷、黑砷纳米带构建异质结构在2%、4%、6%和8%四种拉伸应变作用下热电性能调控机理.研究结果表明,6%拉伸应变较其他情形,能够更有效抑制声子输运行为;与此同时,拉伸应变对于器件的电子输运的调控效果并不明显.在费米能附近,黑磷/黑砷异质结纳米器件在6%拉伸应变调控下热电优值达到最大值2.31.

关键词：黑磷黑砷异质结应力热电性质

基于石墨烯电极TCNQ分子结热/电输运性质理论研究

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原子与分子物理学报 2025年第3期42卷 135-140页

作者：刘仪伟邱乙峰张蓓新疆大学物理科学与技术学院乌鲁木齐830046

本文采用密度泛函理论和非格林平衡函数,对基于石墨烯电极的7,7,8,8-四氰基苯醌二甲烷(Tetracyanoquinodimethane,TCNQ)分子结热/电输运性质进行系统研究.研究结果表明:随着中心TCNQ分子个数的增加,声子透射系数明显降低,即声子透射行... 详细信息

本文采用密度泛函理论和非格林平衡函数,对基于石墨烯电极的7,7,8,8-四氰基苯醌二甲烷(Tetracyanoquinodimethane,TCNQ)分子结热/电输运性质进行系统研究.研究结果表明:随着中心TCNQ分子个数的增加,声子透射系数明显降低,即声子透射行为受到极大抑制.与此同时,电子透射系数也有一定程度的减小.在热/电参数的协同作用下,伴随分子数量的增加分子结热电转换性能呈上升趋势,1TCNQ热电优值(ZT)为0.016,而2TCNQ则上升了1个数量级,ZT值达到0.11.最后,我们对分子结依赖于分子结构个数的自旋输运性质进行研究,发现TCNQ分子结具有显著的自旋过滤效应,其过滤能力随着TCNQ分子数量的增加而增加.该工作可为实验制备分子热电器件提供理论依据和数据支持.

关键词：锯齿状石墨烯纳米带 TCNQ分子自旋输运性质自旋过滤效应

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