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Normality of Tetravalent Cayley Graphs of Odd Prime-cube Order and Its Application

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Acta Mathematica Sinica,English Series 2005年第4期21卷 903-912页

作者： Yan quan feng Ming Yao XU Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China LMAM Institute of Mathematics Peking University Beijing 100871 P. R. China

Let p be an odd prime. In this paper we prove that all tetravalent connected Cayley graphs of order p^3 are normal. As an application, a classification of tetravalent symmetric graphs of odd prime-cube order is given.

关键词： Cayley graph Normal Cayley graph Symmetric graph

Circulant Double Coverings of a Circulant Graph of Valency Five

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Acta Mathematica Sinica,English Series 2007年第1期23卷 23-28页

作者： Rong quan feng Jin Ho KWAK LMAM School of Mathematical Sciences Peking University Beijing 100871 P. R. China Mathematics Pohang University of Science and Technology Pohang 790-784 Korea

Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 （2004）1 enumerated the isomorphism classes of circulant double coverings of a certain type, called a typical covering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21,386 400 （2005）], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

关键词： graph covering voltage assignment Cayley circulant graph

“四新”建设背景下高校社会服务类专业人才培养困境与对策

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河北大学成人教育学院学报 2024年第3期26卷 70-77页

作者：帅全锋邢世勇河北大学教育学院河北保定071002

“四新”建设是深化高等教育专业结构调整优化和内涵提升的中国方案,是实现高等教育“高质量建设”的关键举措。高校社会服务类专业不仅是高校专业设置的重要组成部分,还与社会的发展与变革联系最为紧密,“四新”建设必然要求发展高校... 详细信息

“四新”建设是深化高等教育专业结构调整优化和内涵提升的中国方案,是实现高等教育“高质量建设”的关键举措。高校社会服务类专业不仅是高校专业设置的重要组成部分,还与社会的发展与变革联系最为紧密,“四新”建设必然要求发展高校社会服务类专业。目前,高校社会服务类专业存在跨学科程度较低、实践教育缺位、专业师资欠缺、社会资源利用不足等困境。这需要在跨学科课程构建、实践教育、教师队伍建设、社会资源保障等方面提出有针对性的对策,推动高校社会服务类专业的建设和人才培养“四新”理念的高质量发展。

关键词： “四新”建设高校社会服务类专业人才培养

Regular Maps of Graphs of Order 4p

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Acta Mathematica Sinica,English Series 2012年第5期28卷 989-1012页

作者： Jin Xin ZHOU Yan quan feng Department of Mathematics Beijing Jiaotong University

A 2-cell embedding f ： X → S of a graph X into a closed orientable surface S can be described combinatorially by a pair M = （X; p） called a map, where p is a product of disjoint cycle permutations each of which is the permutation of the arc set of X initiated at the same vertex following the orientation of S. It is well known that the automorphism group of M acts semi-regularly on the arc set of X and if the action is regular, then the map M and the embedding f are called regular. Let p and q be primes. Duet al. [J. Algebraic Combin., 19, 123 141 （2004）] classified the regular maps of graphs of order pq. In this paper all pairwise non-isomorphic regular maps of graphs of order 4p are constructed explicitly and the genera of such regular maps are computed. As a result, there are twelve sporadic and six infinite families of regular maps of graphs of order 4p; two of the infinite families are regular maps with the complete bipartite graphs K2p,2p as underlying graphs and the other four infinite families are regular balanced Cayley maps on the groups Z4p, Z22 × Zp and D4p.

关键词： Regular map Cayley map algebraic map 2-cell embedding

基于并环螺芴氧杂蒽类单体的链柔性化蓝光聚合物及其柔性有机发光二极管

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高分子学报 2024年第6期55卷 673-687页

作者：李昊罗曼曼祝守加朱爱云虞梦娜冯全友解令海南京邮电大学信息材料与纳米技术研究院、有机电子与信息显示国家重点实验室、分子系统与有机器件中心南京210023 河南大学柔性电子学院、河南省柔性电子产业技术研究院郑州450046

螺芴氧杂蒽作为一类重要的宽带隙蓝光材料功能砌块,常被用于构筑具有优异光电性能和器件稳定性的聚合物半导体,但螺芴氧杂蒽类聚合物柔性化的构筑却很少被报道.基于此,本文报道了高效合成单螺环/并环螺芴氧杂蒽类单体及其蓝光聚合物,包... 详细信息

螺芴氧杂蒽作为一类重要的宽带隙蓝光材料功能砌块,常被用于构筑具有优异光电性能和器件稳定性的聚合物半导体,但螺芴氧杂蒽类聚合物柔性化的构筑却很少被报道.基于此,本文报道了高效合成单螺环/并环螺芴氧杂蒽类单体及其蓝光聚合物,包括均聚物PC8SFX-Homo、PDSFX-Homo和共聚物PC8SFX-Co、PDSFX-Co,其中并环聚合物(PLQYsol=88.2%,EQEmax=0.52%)无论是发光效率还是柔性器件性能均明显优于单螺环体系(PLQYsol=11.1%,EQEmax=0.17%).且并环聚合物表现出更低的内部应力.同时通过主链柔性化策略引入柔性链段共聚在获得更优柔性的同时能够获得更优异的发光性能和更好的柔性发光二极管器件性能.该工作为构建柔性电子应用的宽带隙深蓝光聚合物及其柔性发光显示器件应用提供了新的思路.

关键词：螺芴氧杂蒽蓝光聚合物链柔性化力学行为柔性有机发光二极管

A new power generation method utilizing a low grade heat source

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第2期13卷 140-145页

作者： Wei-feng WU Xin-ping LONG Xiao-ling YU quan-ke feng School of Energy and Power Engineering Xi ＇an Jiaotong University Xi ＇an 710049 China School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China

Energy crisis make the effective use of low grade energy more and more urgent. It is still a worldwide difficult conundrum. To efficiently recover low grade heat, this paper deals with a theoretical analysis of a new power generation method driven by a low grade heat source. When the temperature of the low grade heat source exceeds the saturated temperature, it can heat the liquid into steam. If the steam is sealed and cooled in a container, it will lead to a negative pressure condition. The proposed power generation method utilizes the negative pressure condition in the sealed container, called as a condensator. When the condensator is connected to a liquid pool, the liquid will be pumped into it by the negative pressure condition. After the conden- sator is filled by liquid, the liquid flows back into the pool and drives the turbine to generate electricity. According to our analysis, for water, the head pressure of water pumped into the condensator could reach 9.5 m when the temperature of water in the pool is 25 ℃, and the steam temperature is 105 ℃. Theoretical thermal efficiency of this power generation system could reach 3.2% to 5.8% varying with the altitude of the condensator to the water level, ignoring steam leakage loss.

关键词： Low grade heat Power generation Condensation Energ-v storage Renewable energy

东北黑土区耕地利用效益空间差异及影响因素分析

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农业现代化研究 2024年第3期45卷 409-421页

作者：李全峰严建文瞿诗进郭文昊东北农业大学公共管理与法学院黑龙江哈尔滨150030 黑龙江省土地遥感大数据技术创新中心黑龙江哈尔滨150030 中国地质大学公共管理学院湖北武汉430074

耕地利用效益是评估区域耕地利用协调程度的必要前提,也是农业高效可持续发展的重要保障。本文以东北黑土区为研究区,依据耕地利用系统理论,构建“经济-社会-生态”效益框架,运用综合评价法、探索性数据分析法与地理探测器模型,从县域... 详细信息

耕地利用效益是评估区域耕地利用协调程度的必要前提,也是农业高效可持续发展的重要保障。本文以东北黑土区为研究区,依据耕地利用系统理论,构建“经济-社会-生态”效益框架,运用综合评价法、探索性数据分析法与地理探测器模型,从县域尺度分析2020年东北黑土区耕地利用效益空间差异和影响因素。结果显示:1)耕地利用综合效益、经济效益和生态效益整体上均呈现为由南部和中部平原地区向西部和北部低丘缓坡地形区减少趋势,社会效益则主要表现为由南部向北部递减的分布趋势。2)耕地利用综合效益整体上具有显著的集聚特征,高集聚主要在辽宁省南部以及北部黑龙江省县域范围分布,低集聚则集中分布在东部内蒙古和中部吉林省县域。3)从影响因素来看,黑土区耕地利用综合效益中气候、农业机械化程度和农作物复种指数是关键影响因素,且因素间的交互作用影响更加显著。为更好的提升黑土区耕地利用效益,需要把握乡村振兴协作、保护经营机制、农业综合措施和绿色技术创新等方面的促进作用,实现农业资源高效利用和可持续发展。

关键词：耕地利用综合效益空间差异影响因素县域东北黑土区

A Pohozaev Identity for the Fractional Hnon System

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Acta Mathematica Sinica,English Series 2017年第10期33卷 1382-1396页

作者： Pei MA feng quan LI Yan LI Institute of Mathematics School of Mathematical Sciences Nanjing Normal University Nanjing 210023 P. R. China Department of Mathematical Sciences Yeshiva University New York NY 10033 USA School of Mathematical Sciences Dalian University of Technology Dalian 116024 P. R. China

In this paper, we study the Pohozaev identity associated with a Henon-Lane-Emden sys- tem involving the fractional Laplacian：{（-△）^su=｜x｜^aυ^p,x ∈Ω,（-△）^sυ=｜x｜^av^p,x ∈Ω u=υ=0, x∈R^b／Ω,in a star-shaped and bounded domain Ω for s E （0, 1）. As an application of our identity, we deduce the nonexistence of positive solutions in the critical and supercritieal cases.

关键词： Pohozaev identity fractional Laplacian Henon system nonexistence of solutions

Typical Frobenius Coverings

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Acta Mathematica Sinica,English Series 2010年第11期26卷 2209-2214页

作者： Yan WANG Rong quan feng Jaeun LEE Department of Mathematics Yah Tai University Yah Tai 264005 P. R. China LMAM School of Mathematical Sciences Peking University Beijing 100871 P. R. China Department of Mathematics Yeungnam University Kyongsan 712-749 Korea

A covering p from a Cayley graph Cay（G, X） onto another Cay（H, Y） is called typical Frobenius if G is a Frobenius group with H as a Frobenius complement and the map p ： G →H is a group epimorphism. In this paper, we emphasize on the typical Frobenius coverings of Cay（H, Y）. We show that any typical Frobenius covering Cay（G, X） of Cay（H, Y） can be derived from an epimorphism /from G to H which is determined by an automorphism f of H. If Cay（G, X1） and Cay（G, X2） are two isomorphic typical Frobenius coverings under a graph isomorphism Ф, some properties satisfied by Фare given.

关键词： Frobenius group typical Frobenius covering isomorphic