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Heat kernel estimates on effective resistance metric spaces

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Progress in Natural Science:Materials International 2007年第7期17卷 775-783页

作者： Hu Jiaxin Ji Yuan wen zhiying (department of Mathematical Sciences,tsinghua university,beijing 100084,china) [a]department of Mathematical Sciences Tsinghua University Beijing China

We obtain two-sided estimates of heat kernels on effective-resistance metric spaces by using an analytic *** applications,such as on post-critically finite self-similar sets and on products of effective resistance spa... 详细信息

关键词： Heat kernel effective resistance Dirichlet form Green’s function

Some Boundary Fractal Properties of the Convolution Transform of Measures by an Approximate Identity

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Acta Mathematica Sinica,English Series 1999年第2期15卷 207-214页

作者： zhiying wen, department of mathematics, Wuhan university, Wuhan 430072, P. R. china department of Applied mathematics, tsinghua university, beijing 100084, P. R. chinaE-mail: wenzy@tsinghua.edu.cnYiping Zhang, department of mathematics, Wuhan university, Wuhan 430072, P. R. chinaE-mail: ypzhang@*** department of mathematics Wuhan University Wuhan P. R. China department of Applied mathematics Tsinghua University Beijing P. R. China

We consider the convolution transforms of measures on Rd defined by some approximate identity. We shall establish some relations between the irregular boundary properties of the convolution function and the local Lipschitz exponent of the measure. In particular, the results can be applied to the Poisson and Gauss-Weierstrass kernels. We can then obtain some singular boundary behavior of positive harmonic or parabolic functions on R+d+1 by multifractal analysis of measures.

关键词： Approximate identity Multifractal Logarithmic density

Spectrality of planar self-affine measures with two-element digit set

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Science china mathematics 2012年第3期55卷 593-605页

作者： LI JianLin wen zhiying College of mathematics and Information Science Shaanxi Normal University Xi＇an 710062 China department of Mathematical Sciences Tsinghua University Beijing 100084 China

The iterated function system with two element digit set is the simplest case and the most important case in the study of self affine *** one dimensional case corresponds to the Bernoulli convolution whose spectral property is *** higher dimensional analogue is not known,for which two conjectures about the spectrality and the non spectrality remain *** the present paper,we consider the spectrality and non spectrality of planar self affine measures with two element digit *** give a method to deal with the two dimensional case,and clarify the spectrality and non spectrality of a class of planar self affine *** result here provides some supportive evidence to the two related conjectures.

关键词： self-affine measure orthogonal exponentials spectrality Bernoulli convolution compatible pair

DERIVED SEquENCES AND THE FACTOR SPECTRUM OF THE PERIOD-DOUBLING SEquENCE

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Acta Mathematica Scientia 2021年第6期41卷 1921-1937页

作者： Yuke HUANG zhiying wen School of Science Beijing University of Posts and TelecommunicationsBeijing100876China department of Mathematical Sciences Tsinghua UniversityBeijing100084China

Factor properties and their structures are important themes in combinatorics on *** D be the infinite one-sided sequence over the alphabet{a,b}generated by the period-doubling substitutionσ(a)=ab andσ(b)=*** this paper,we determine the derived sequence D_(ω)(D)for any factorω■D,and study some factor spectra using the structures of derived *** also prove the reflexivity property of derived sequences.

关键词： combinatorics on words envelope word derived sequence factor spectrum reflexivity of derived sequence

The Factor Spectrum and Derived Sequence

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Journal of Mathematical Research with Applications 2019年第6期39卷 718-732页

作者： Yuke HUANG zhiying wen School of Science Beijing University of Posts and Telecommunications department of Mathematical Sciences Tsinghua University

Given a sequence ρ over a finite alphabet A, an important topic in combinatorics on words is to find out all factors ω of ρ and positive integers p such that ωp(the p-th occurrence of ω) fulfills property P. This problem is equivalent to determining a notion called the factor spectrum. Determining the factor spectrum is a difficult problem. To this aim, we introduce several notions, such as: kernel word, envelope word, return word and derived sequence of each factor ω. Using the factor spectrum and derived sequence, we can solve some enumerations of factors, such as the numbers of palindromes, fractional powers, etc. We will show some results for several sequences, such as the Fibonacci sequence, the Tribonacci sequence, the Period-doubling sequence, etc. And we think that these notions and methods are suitable for all recurrent sequences.

关键词： kernel word envelope word return word derived sequence the factor spectrum

基于遥感影像的火星尘暴时空概率分析与预报——以“天问一号”任务为例

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科学通报 2025年第1期70卷 107-120页

作者：杨茜李勃田园温埔正张江曲少杰戎昭金山东大学空间科学与物理学院山东省光学天文与日地空间环境重点实验室威海264209 北京空间飞行器总体设计部北京100094 中国科学院地质与地球物理研究所中国科学院地球与行星物理重点实验室北京100029

尘暴是火星表面沙尘颗粒在剧烈的大气运动下形成的扬尘现象,局部尘暴可持续几个火星日(sols),大型甚至全球性尘暴可持续长达几个月.火星尘暴事件严重威胁探测器着陆过程的安全性,并可能加剧火星车太阳能帆板表面的沙尘沉积进而导致火星... 详细信息

尘暴是火星表面沙尘颗粒在剧烈的大气运动下形成的扬尘现象,局部尘暴可持续几个火星日(sols),大型甚至全球性尘暴可持续长达几个月.火星尘暴事件严重威胁探测器着陆过程的安全性,并可能加剧火星车太阳能帆板表面的沙尘沉积进而导致火星车供电不足.为保障火星探测任务着陆过程的安全,应开展火星尘暴事件的时空概率分析并对着陆前的尘暴事件进行预报.本文以中国首次火星探测任务“天问一号”为例,开展了:(1)基于长时间序列(MY24~28)火星遥感影像(MDGMs)来提取尘暴对象和尘暴序列,建立乌托邦平原(Utopia Planitia)研究区的尘暴时空数据库;(2)计算研究区中尘暴出现的时空概率,并对“天问一号”任务的着陆时间、地点以及“祝融号”火星车工作和休眠期内的尘暴活动进行分析评价;(3)完成“天问一号”主选和备选着陆圆的原生尘暴划分和尘暴序列的特征提取,并实现了“天问一号”任务着陆前的尘暴预报分析.未来应当结合大气环流模型模拟和计算的大气物理等参数(温度、压强、光学深度、风速和风向等)来综合研究尘暴等大气活动的机理和影响因子,以提高尘暴分析和预报的准确性以及实时性.

关键词：火星尘暴乌托邦平原天问一号时空概率尘暴预报

Decomposition of L^P( Da) Space and Boundary Value of Holomorphic Functions

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Chinese Annals of mathematics,Series B 2017年第5期38卷 1093-1110页

作者： Zhihong wen Guantie DENG Cuiqiao WANG Feifei qu department of mathematics and Statistics Jiangsu Normal University Xuzhou 221116 Jiangsu China School of Mathematical Sciences Key Laboratory of Mathematics and Complex Systems of Ministry of Education Beijing Normal University Beijing 100875 China

This paper deals with two topics mentioned in the title. First, it is proved that function f in L^P（ Da） can be decomposed into a sum g ＋ h, where Da is an angular domain in the complex plane, g and h are the non-tangential limits of functions in H^P（Da） and H^P（aD^c） in the sense of LP（Da）, respectively. Second, the sufficient and necessary conditions between boundary values of holomorphic functions and distributions in n-dimensional complex space are obtained.

关键词： Hardy space Rational function Holomorphic function Distribution

TiO2 sensitized by red-, green-, blue-emissive carbon dots for enhanced H2 production

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Rare Metals 2019年第5期38卷 404-412页

作者： Dong-Xue Yang Dan qu Xiang Miao wen-Shuai Jiang Li An Yuan-Jing wen Dan-Dan Wu Zai-Cheng Sun beijing Key Laboratory for Green Catalysis and Separation Department of Chemistry and Chemical Engineering School of Environmental and Energy Beijing University of Technology

Carbon dots(Cdots)with a broad light absorption range could be a potential stable sensitizer for TiO2,which is an excellent ultraviolet(UV)response ***,we systematically investigated the different color emissive Cdots-sensitized TiO2 for H2 ***,all kinds of Cdots enhanced the photocatalytic properties of *** the Cdots-sensitized TiO2 exhibits visible light H2 production due to their absorption in the visible light *** photocurrent and H2 production amount display strong dependence on the light absorption range of *** blue-emissive Cdots endow the weak H2 production rate due to its weak absorption in the visible *** enhanced photocatalytic activities are mainly contributed to the strong light absorbance and high-efficient charge *** light absorption of green-and red-emissive Cdots is another main factor for the high catalytic activities besides charge separation.

关键词： TiO2 Carbon dots Visible light absorption Sensitizer H2 production

Coherent effects in a three-photon CPT process of Ca＋

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Frontiers of physics 2011年第3期6卷 258-261页

作者： qu LIU Bao-quan OU Xi-wen ZHU Ke-lin GAO State Key Laboratory of Magnetic Resonance and Atornic and Molecular Physics Wuhan lnstitute of Physics and Mathematics （WIPM） Chinese Academy of Sciences （CAS） Wuhan 430071 China Centers for Cold Atom Physics CAS Wuhan 430071 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China department of Physics Science College National University of Defense Technology Changsha 410073 China

Linewidth narrowing and other quantum coherent effects based on three-photon coherent population trapping （CPT） in Ca＋ ions are investigated. If the propagation directions of the three lasers obey the phase matching condition, the dark linewidth resulting from the CPT can be very narrow, and it can be controlled by adjusting the parameters of the lasers.

关键词： coherent population trapping (CPT) linewidth coherent effects