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Vectorial Ekeland variational principle for systems of equilibrium problems and its applications

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Science China Mathematics 2017年第7期60卷 1259-1280页

作者： qiu JingHui School of Mathematical Sciences Soochow University Suzhou 215006 China

For a family of vector-valued bifunctions,we introduce the notion of sequentially lower monotonity,which is strictly weaker than the lower semi-continuity of the second variables of the ***,we give a general version of vectorial Ekeland variational principle(briefly,denoted by EVP) for a system of equilibrium problems,where the sequentially lower monotone objective bifunction family is defined on products of sequentially lower complete spaces(concerning sequentially lower complete spaces,see Zhu et al(2013)),and taking values in a quasi-ordered locally convex ***,the perturbation consists of a subset of the ordering cone and a family {p_i}_(i∈I) of negative functions satisfying for each i∈I,p_i(x_i,y_i) = 0 if and only if x_i=y_*** the general version,we can deduce several particular equilibrium versions of EVP,which can be applied to show the existence of solutions for countable systems of equilibrium *** particular,we obtain a general existence result of solutions for countable systems of equilibrium problems in the setting of sequentially lower complete *** weakening the compactness of domains and the lower semi-continuity of objective bifunctions,we extend and improve some known existence results of solutions for countable system of equilibrium problems in the setting of complete metric spaces(or Fréchet spaces).When the domains are non-compact,by using the theory of angelic spaces(see Floret(1980)),we generalize some existence results on solutions for countable systems of equilibrium problems by extending the framework from reflexive Banach spaces to the strong duals of weakly compactly generated spaces.

关键词： Ekeland variational principle equilibrium problem system of equilibrium problems quasi-ordered locally convex space angelic space sequentially lower complete space

On Pointwise Bounded Approximation

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Acta Mathematica Sinica,English Series 2009年第7期25卷 1217-1222页

作者： Zhijian qiu School of Mathematics Southwestern University of Finance and Economics Chengdu 610074 P. R. China

Let G be an open subset in the extended complex plane and let A（G） denote the algebra of all functions analytic on G and continuous on G. We call a domain multi-nicely connected if there is a circular domain W and a conformal map ~ from W onto G such that the boundary value function of φ is univalent almost everywhere with respect to the arclength on aW. Suppose that every component of G is finitely connected and none of the components of G have single point boundary components. We show that for every bounded analytic function on G to be the pointwise limit of a bounded sequence of functions in A（G）, it is necessary and sufficient that each component of G is multi-nicely connected and the harmonic measures of G are mutually singular. This generalizes the corresponding result of Davie for the case when the components of G are simply connected.

关键词： pointwise approximation harmonic measure Dirichlet algebra

The braid group for a quiver with superpotential

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Science China Mathematics 2019年第7期62卷 1241-1256页

作者： Yu qiu Yau Mathematical Sciences Center Tsinghua University

We survey various generalizations of braid groups for quivers with superpotential and focus on the cluster braid groups, which are introduced in a joint work with King (2018). Our motivations come from the study of cl... 详细信息

关键词： braid groups mapping class groups spherical twists quiver with potential cluster algebras stability conditions

World Meteorological Organization: scaling the peaks for social benefits

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National Science Review 2018年第6期5卷 947-952页

作者： Jane qiu NSR

Climate change is tightening its grip on high mountains. Yet, unlike their island counterparts, the ordeals facing mountain communities are under-studied and under-appreciated. But that’s about to change. The World M... 详细信息

关键词： scaling the peaks for social benefits World Meteorological Organization Organization

ASSESSMENT OF THE SFIM ALGORITHM

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Chinese Geographical Science 2004年第1期14卷 48-56页

作者： XUHan-qiu CollegeofEnvironmentandResources FuzhouUniversityFuzhou350002P.R.China

Fusion of images with different spatial and spectral resolutions can improve the visualization of the images. Many fusion techniques have been developed to improve the spectral fidelity and/or spatial texture quality of fused imagery. Of them, a recently proposed algorithm, the SFIM (Smoothing Filter-based Intensity Modulation), is known for its high spectral fidelity and simplicity. However, the study and evaluation of the algorithm were only based on spectral and spatial criteria. Therefore, this paper aims to further study the classification accuracy of the SFIM-fused imagery. Three other simple fusion algorithms, High-Pass Filter (HPF), Multiplication (MLT), and Modified Brovey (MB), have been employed for further evaluation of the SFIM. The study is based on a Landsat-7 ETM+ sub-scene covering the urban fringe of southeastern Fuzhou City of *** effectiveness of the algorithm has been evaluated on the basis of spectral fidelity, high spatial frequency information absorption, and classification accuracy. The study reveals that the difference in smoothing filter kernel sizes used in producing the SFIM-fused images can affect the classification accuracy. Compared with three other algorithms, the SFIM transform is the best method in retaining spectral information of the original image and in getting best classification results.

关键词： data fusion SFIM algorithm evaluation classification remote sensing

氨基化磁性还原氧化石墨烯的制备及其对甲基橙吸附研究

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仲恺农业工程学院学报 2025年第1期38卷 6-11页

作者：丘关南龚圣肇庆旭源环保科技有限公司广东肇庆526236 仲恺农业工程学院化学化工学院广东广州510225

水中存在有机染料会造成生态和公共卫生问题,对受到有机染料污染的水进行修复具有重要意义.本研究采用共沉淀法合成氨基化磁性还原氧化石墨烯(NH2-MrGO),并用其吸附水中的甲基橙(Methyl Orange,MO)染料;通过SEM、Zeta电位、FT-IR和磁滞... 详细信息

水中存在有机染料会造成生态和公共卫生问题,对受到有机染料污染的水进行修复具有重要意义.本研究采用共沉淀法合成氨基化磁性还原氧化石墨烯(NH2-MrGO),并用其吸附水中的甲基橙(Methyl Orange,MO)染料;通过SEM、Zeta电位、FT-IR和磁滞回线等先进技术对合成的复合材料进行表征,考察温度和pH值对其吸附性能的影响.结果表明,NH2-MrGO对MO的最大吸附量为15.7 mg/g,去除率为78.5%,且吸附过程符合Freundlich模型,可为水中的有机染料污染物的治理与消除提供实践支持与数据参考.

关键词：还原氧化石墨烯氨基化磁性吸附甲基橙

Boosting the discovery of 3D topological materials: mixing chemistry with physics via a two-step computational screening strategy

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National Science Review 2018年第3期5卷 316-318页

作者： Xing-qiu Chen Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

Topological materials in crystal solids,including topological insulators(TIs),crystalline insulators(TCIs),Dirac semimetals(DSMs),topological Weyl semimetals(WSMs),topological Dirac or Weyl nodal line semimetals(NLSMs)and beyond[1–5],are mainly featured with topological,protected non-trivial surface states and their bulk phases are insulators or semimetals with the proper presence of Dirac cones,Weyl nodes

关键词： Bi mixing chemistry with physics via a two-step computational screening strategy Boosting the discovery of 3D topological materials

Time—Frequency Analysis of Electromagnetic Pulse Response from a Spherical Target

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Chinese Physics Letters 2003年第5期20卷 660-663页

作者： CHENDong JINYa-qiu CenterforWaveScatteringandRemoteSensing andSchoolofInformationScienceandEngineeringFudauUniversityShanghai200433

Transient backscattering from a spherical target under incidence of an electromagnetic short pulse is studied. The target can be a perfectly conducting sphere, a dielectric sphere or a dielectric spherical shell. To understand the scattering mechanism from transient impulse echoes for target detection, both the short-time Fourier transform (STFT) and the wavelet transform (WT) are applied to retrieval of scattering information from the backscattering data. Analysis in both the time and frequency domains demonstrates that the WT is more feasible than the STFT to clarifying scattering process of the scatterer because of its excellent multi-resolution characteristic. This technique shall be helpful for scattering analysis and detection of more complex single or multi-targets.

关键词：电磁脉冲响应球形物体时频分析瞬时反向散射快速傅里叶变换小波变换雷达

顶空固相微萃取/气相色谱法快速萃取-解吸土壤中7种芳香族化合物

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分析测试学报 2025年第1期44卷 172-179页

作者：李丙阳王钊陈佳邱洪灯新疆师范大学化学化工学院新疆乌鲁木齐830000 中国科学院兰州化学物理研究所甘肃省天然药物重点实验室甘肃兰州730000

利用氧化石墨烯功能化修饰固相微萃取(GO@SPME)针,结合气相色谱(GC)-氢火焰离子化检测器(FID)建立了检测土壤中7种挥发性芳香烃及其衍生物(包括甲苯、氯苯、乙苯、对二甲苯、邻二甲苯、硝基苯和萘)的快速萃取和解吸策略。考察了萃取液... 详细信息

利用氧化石墨烯功能化修饰固相微萃取(GO@SPME)针,结合气相色谱(GC)-氢火焰离子化检测器(FID)建立了检测土壤中7种挥发性芳香烃及其衍生物(包括甲苯、氯苯、乙苯、对二甲苯、邻二甲苯、硝基苯和萘)的快速萃取和解吸策略。考察了萃取液体积、搅拌速率、萃取温度、加盐量、解吸温度、萃取时间和解吸时间对目标物萃取效果的影响,确定在土壤样品中加入内标物质(氘代甲苯),经甲醇提取,顶空固相微萃取快速富集,再结合GC-FID进行检测,基质匹配内标法定量分析。在优化的实验条件下,该方法在15 s内可实现对目标物的快速萃取与解吸(萃取时间12 s,解吸时间3 s)。土壤样品中7种挥发性芳香烃及其衍生物的线性关系良好,相关系数(r^(2))均不小于0.9989,方法检出限(LOD,S/N=3)为1.71~11.60μg/g,定量下限(LOQ,S/N=10)为5.70~38.67μg/g;在3个不同加标水平(60、120、180μg/g)下的平均回收率为87.3%~109%,相对标准偏差(RSD)不大于12%。该方法前处理简单快速,成本较低,数据稳定可靠,适用于土壤样品中芳香族类化合物的快速检测。

关键词：芳香烃及其衍生物氧化石墨烯顶空固相微萃取气相色谱法快速萃取-解吸策略土壤