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Einstein Finsler metrics and Killing vector fields on Riemannian manifolds

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Science China Mathematics 2017年第1期60卷 83-98页

作者： cheng xinyue SHEN ZhongMin School of Mathematics and Statistics Chongqing University of Technology Department of Mathematical Sciences Indiana University-Purdue University

We use a Killing form on a Riemannian manifold to construct a class of Finsler metrics. We find equations that characterize Einstein metrics among this class. In particular, we construct a family of Einstein metrics on S^3 with Ric = 2F^2, Ric = 0 and Ric =-2F^2, respectively. This family of metrics provides an important class of Finsler metrics in dimension three, whose Ricci curvature is a constant, but the flag curvature is not.

关键词： Killing vector field Finsler metric (α β)-metric Ricci curvature Einstein metric Ricci-flat metric

On a class of two-dimensional Finsler manifolds of isotropic S-curvature

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Science China Mathematics 2018年第1期61卷 57-72页

作者： xinyue cheng Zhongmin Shen Guojun Yang School of Mathematics and Statistics Chongqing University of Technology Department of Mathematical Sciences Indiana University-Purdue University Department of Mathematics Sichuan University

For an(α, β)-metric(non-Randers type) of isotropic S-curvature on an n-dimensional manifold with non-constant norm ‖β‖α, we first show that n = 2, and then we characterize such a class of two-dimensional(α, β)... 详细信息

关键词： (α,β)-metric Randers metric S-curvature

ON(α,β)-METRICS OF CONSTANT FLAG CURVATURE

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Acta Mathematica Scientia 2022年第2期42卷 755-768页

作者： Guangzu CHEN xinyue cheng School of Science East China Jiao Tong UniversityNanchang 330013China School of Mathematical Sciences Chongqing Normal UniversityChongqing 401331China

In this paper,we study the(α,β)-metrics of constant flag *** characterize almost regular(α,β)-metrics of constant flag curvature under the condition that β is a homothetic 1-form with respect to ***,we prove that if a regular(α,β)-metric is of constant flag curvature and β is a Killing 1-form with constant length,then it must be a Riemannian metric or locally Minkowskian.

关键词： (α,β)-metric flag curvature S-curvature mean Landsberg curvature Riemannian metric Minkowski metric homothetic 1-form

Sulfur Vacancies Tune the Charge Distribution of NiCo_(2)S_(4) for Boosting the Energy Density of Stretchable Yarn‑Based Zn Ion Batteries

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Advanced Fiber Materials 2023年第2期5卷 650-661页

作者： xinyue cheng Xu Yang Yanan Zhang Pengfei Lv Jixing Yang Fenglin Huang Qufu Wei Key Laboratory of Eco‑Textiles Ministry of EducationJiangnan UniversityWuxi 214122People’s Republic of China Fujian Key Laboratory of Novel Functional Textile Fibers and Materials Minjiang UniversityFuzhou 350108People’s Republic of China School of Materials Science and Engineering Tianjin UniversityTianjin 300072People’s Republic of China State Key Laboratory of Molecular Engineering of Polymers Fudan UniversityShanghai 200438People’s Republic of China

Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy ***,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical ***,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal *** aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage *** high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and ***,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical *** a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical *** proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.

关键词： Sulfur vacancies NiCo_(2)S_(4-x)nanotube arrays Stretchable Yarn-based zinc ion batteries Wearable energy textiles

Effects of α-pinene on the pinewood nematode（Bursaphelenchus xylophilus） and its symbiotic bacteria

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Effects of α-pinene on the pinewood nematode（Bursaphelench...

中国植物病理学会2019年学术年会

作者： Wang Xu Yu Yanxue Ge Jianjun cheng xinyue College of Life Sciences Beijing Normal University Chinese Academy of Inspection and Quarantine

The pinewood nematode（PWN）,Bursaphelenchus xylophilus,is an important plantparasitic nematode that can cause severe mortality of pine *** PWN-induced harm to plants may be closely related to the abundance and diversity of the symbiotic microorganisms of the parasitic *** this study,nematodes were divided into untreated and antibiotic-treated *** were treated by fumigation with different amounts of a-pinene,and the resultant mortality rates were analyzed *** of symbiotic bacteria were calculated as colony-forming units/*** sequencing was used to investigate the bacterial community *** results showed that the mortality of nematodes increased slightly with increasing concentration of a-pinene,and nematodes untreated with antibiotics were more sensitive to a-pinene than those treated with *** highest abundance of symbiotic bacteria was obtained via medium and low levels of a-pinene,but for which community diversity was the lowest（Shannon and Simpson indexes）.The proportion of Pseudomonas *** the symbiotic bacteria of nematodes without antibiotics was relatively high（more than 70%）,while that of Stenotrophomonas *** low（6%-20%）.However,the proportion of Stenotrophomonas *** larger than that of the Pseudomonas *** the symbiotic bacteria associated with the antibiotictreated *** *** after pinene treatment,whereas Stenotrophomonas *** results indicate that although a-pinene has low toxicity to PWNs over a short time period,α-pinene ultimately influences the abundance and community diversity of the symbiotic bacteria of these nematodes;this influence may potentially disturb the development and reproduction of nematodes in the process of infecting pine trees.

关键词： pinewood nematode(PWN) Bursaphelenchus xylophilus α-pinene symbiotic bacteria

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Finsler几何中的体积比较定理

中国科学：数学 2024年第10期54卷 1489-1508页

作者：程新跃冯娅璐重庆师范大学数学科学学院重庆401331

本文着重介绍关于Finsler几何中的体积比较定理及其应用的重要研究进展.首先,介绍Finsler几何中关于距离函数的Laplace比较定理.然后,分别在Ricci曲率Ric、加权Ricci曲率RicN和Ric∞有界的条件下介绍Finsler流形上的体积比较定理及其相... 详细信息

本文着重介绍关于Finsler几何中的体积比较定理及其应用的重要研究进展.首先,介绍Finsler几何中关于距离函数的Laplace比较定理.然后,分别在Ricci曲率Ric、加权Ricci曲率RicN和Ric∞有界的条件下介绍Finsler流形上的体积比较定理及其相关的重要应用.本文的主要结果既有对Riemann几何中的体积比较定理的自然推广,又有在Finsler几何中的创新发展,对推进Finsler流形上的整体几何与分析的研究有着极为重要的价值.

关键词： Finsler流形体积比较定理 Ricci曲率加权Ricci曲率距离函数

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二氧化锰基纤维状超级电容器的研究进展

复合材料学报 2023年第6期40卷 3187-3196页

作者：田晓娟程新跃魏取福江南大学纺织科学与工程学院无锡214122

二氧化锰(MnO_(2))具有高容量、环保、低成本等优点,是一种极具发展前景的超级电容器电极材料。随着智能可穿戴技术的不断发展,纤维状超级电容器由于其灵活性和可编织性受到广泛关注。将高性能的MnO_(2)电极材料构建纤维状超级电容器作... 详细信息

二氧化锰(MnO_(2))具有高容量、环保、低成本等优点,是一种极具发展前景的超级电容器电极材料。随着智能可穿戴技术的不断发展,纤维状超级电容器由于其灵活性和可编织性受到广泛关注。将高性能的MnO_(2)电极材料构建纤维状超级电容器作为可穿戴技术的重要组成部分也被不断研究和拓展创新。根据目前MnO_(2)基纤维状超级电容器的发展和可穿戴能源产品的需求,本文对温和中性电解质中MnO_(2)的储能机制进行分析,针对MnO_(2)基纤维状超级电容器在实际可穿戴应用中存在的连续化生产困难、实际利用率低等问题,提出了解决策略,深入分析了各种解决策略的利弊及方案中材料的协同作用,为未来的研究方向提供新的思路,最后对其面临的挑战和未来的发展进行了归纳总结,MnO_(2)基纤维状超级电容器有望在今后取得重大进展,成为新一代能源纺织品的高效供能体系。

关键词：二氧化锰(MnO_(2)) 纤维状超级电容器智能可穿戴应用解决策略

合肥市不同功能街道峡谷PM_(2.5)和PM_(10)时空分布特征及影响因素分析

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生态环境学报 2022年第3期31卷 524-534页

作者：王薇程歆玥安徽建筑大学建筑与规划学院安徽合肥230601 安徽建筑大学建成环境与健康重点实验室安徽合肥230601

以PM_(2.5)和PM_(10)为代表的空气污染对城市居民的生活产生了巨大的影响。街道峡谷是城市的重要构成部分,是城市居民生活的主要场所之一。选择合肥市3种典型功能的街道峡谷,监测PM_(2.5)和PM_(10)质量浓度变化,采用相关分析和回归分析... 详细信息

以PM_(2.5)和PM_(10)为代表的空气污染对城市居民的生活产生了巨大的影响。街道峡谷是城市的重要构成部分,是城市居民生活的主要场所之一。选择合肥市3种典型功能的街道峡谷,监测PM_(2.5)和PM_(10)质量浓度变化,采用相关分析和回归分析等方法,研究不同功能街道峡谷PM_(2.5)和PM_(10)的差异及其影响因素,并采用空气质量评价模型对其空气质量进行评价。结果表明,(1)街道峡谷PM_(2.5)和PM_(10)质量浓度之间具有较高的相关性,波峰出现在08:00—09:00,波谷多出现在14:00—15:00。PM_(2.5)质量浓度波峰为61.22—73.71μg·m^(−3),波谷为32.73—33.59μg·m^(−3);PM_(10)质量浓度波峰为67.65—85.19μg·m^(−3),波谷为37.35—39.81μg·m^(−3),均位于一级标准极限值上下。(2)合肥市办公型街道峡谷与商业型街道峡谷日变化呈明显的下降型双峰形式,居住型街道峡谷呈平稳型双峰形式。街道峡谷PM_(2.5)和PM_(10)质量浓度:办公型>商业型>居住型。街道峡谷内PM_(2.5)和PM_(10)质量浓度峰值多在下沉广场和次干道,低谷值多在主干道绿化带旁和主次干道交叉口。(3)夏季,合肥市街道峡谷PM_(2.5)质量浓度与PM_(10)质量浓度、相对湿度呈现显著的正相关,与空气温度呈现显著的负相关。(4)运用AQI对合肥市夏季不同功能街道峡谷进行评价,其空气质量级别以优良为主,空气质量级别多分布在一级和二级。该研究对合肥市不同功能街道峡谷的污染物浓度进行对照,为街道峡谷特征功能评估提供了基本参数。

关键词：街道峡谷功能分区空气污染空气质量评价 PM_(2.5) PM_(10)

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我国及邻近地区斑腿蝗科区系及其起源研究

昆虫学报 1999年第2期42卷 184-198页

作者：黄春梅成新跃中国科学院动物研究所

根据斑腿蝗科（Ｃａｔａｎｔｏｐｉｄａｅ）在我国各动物地理区的种类组成和区系特点，发现华中区和华北区的区系特点不明显，前者为南北成份的混交区，后者特有种可跨区分布，这与蝗虫有明显的区域和地带分布的特点不相符。为此，作者... 详细信息

根据斑腿蝗科（Ｃａｔａｎｔｏｐｉｄａｅ）在我国各动物地理区的种类组成和区系特点，发现华中区和华北区的区系特点不明显，前者为南北成份的混交区，后者特有种可跨区分布，这与蝗虫有明显的区域和地带分布的特点不相符。为此，作者同意马世骏先生把江汉平原、秦阳山山地、辽黄淮平原划为古北区，成为东方区系。根据我国北方种类与前苏联西伯利亚区系关系密切，而极少数种类与前苏联欧洲部分甚至欧洲部分所共有这种事实，认为世界动物地理区划中应把西伯利亚单独作为一个亚区较合适。

关键词：区系起源斑腿蝗科