检索结果-南通市图书馆

Shrinking target problems for beta-dynamical system

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2013年第1期56卷 91-104页

作者： shen luming WANG BaoWei College of Science Hunan Agricultural University School of Mathematics and Statistics Huazhong University of Science and Technology Lamfa-cnrs umr 6140 Université de Picardie Jules Verne33 rue Saint Leu80039 AmiensFrance

For any β 〉 1, let （[0, 1],Tβ） be the beta dynamical system. For a positive function ψ ： N → R＋ and a real number x0 E [0, 1], we define D（Tβ, ψ, xo） the set of ψ-well approximable points by xo as {x C [0, 1] ： ]Tβ^nx - x0｜（ψ（n） for infinitely many n ∈ N}.In this note, by proving a structure lemma that any ball B（x, r） contains a regular cylinder of comparable length with r, we determine the Hausdorff dimension of the set D（Tβ, ψb, x0） completely for any β 〉 1 and any positive function ψ.

关键词： β -dynamical system shrinking target problems Hausdorff dimension

Modified smoothed particle hydrodynamics approach for modelling dynamic contact angle hysteresis

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第3期35卷 472-485页

作者： Yanyao Bao Ling Li luming shen Chengwang Lei Yixiang Gan School of Civil Engineering University of SydneySydneyNSW 2006Australia

Dynamic wetting plays an important role in the physics of multiphase flow, and has a significant influence on many industrial and geotechnical applications. In this work, a modified smoothed particle hydrodynamics (SPH) model is employed to simulate surface tension, contact angle and dynamic wetting effects at meso-scale. The wetting and dewetting phenomena are simulated in a capillary tube, where the liquid particles are raised or withdrawn by a shifting substrate. The SPH model is modified by introducing a newly developed viscous force formulation at the liquid-solid interface to reproduce the rate-dependent behaviour of the moving contact line. Dynamic contact angle simulations with the interfacial viscous force are conducted to verify the effectiveness and accuracy of this new formulation. In addition, the influence of interfacial viscous forces with different magnitude on the contact angle dynamics is examined by empirical power-law correlations;the derived constants suggest that the dynamic contact angle changes monotonically with the interfacial viscous force. The simulation results are consistent with experimental observations and theoretical predictions, implying that the interfacial viscous force can be associated with the slip length of flow and the microscopic surface roughness. This work demonstrates that the modified SPH model can successfully account for the rate-dependent effects of a moving contact line, and can be used for realistic multiphase flow simulations under dynamic conditions.

关键词： Smoothed particle hydrodynamics Contact angle dynamics Capillary number Interfacial viscous force

HAUSDORFF DIMENSION OF SOME KIND OF ALTERNATING OPPENHEIM SERIES EXPANSION

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Analysis in Theory and Applications 2007年第2期23卷 171-179页

作者： luming shen Chao Ma Yuehua Liu Hunan Agriculture University China Nanjing University China

For Oppenheim series epansions, the authors of [7] discussed the exceptional sets Bm={x∈（0,1]：1〈dj（x）/h（j-1）（d（j-1）（x））≤m for any j ≥2} In this paper, we investigate the Hausdorff dimension of a kind of exceptional sets occurring in alternating Oppenheim series expansion. As an application, we get the exact Hausdorff dimension of the-set in Luroth series expansion, also we give an estimate of such dimensional number.

关键词： alternating Oppenheim series expansion alternating Luroth series expansion,Hausdorff dimension

ON THE ERROR-SUM FUNCTION OF ALTERNATING LüROTH SERIES

在线全文

学校读者我要写书评

暂无评论

Analysis in Theory and Applications 2006年第3期22卷 223-232页

作者： luming shen Chao Ma Jihong Zhang Science College of Hunan Agreculture University China Nanjing University China Wuhan University China

The error-sum function of alternating Lǖroth series is introduced, which, to some extent, discerns the superior or not of an expansion comparing to other expansions. Some elementary properties of this function are st... 详细信息

关键词： Alternating Lǖroth series error-sum function Hausdorff dimension

Some Properties on the Error-Sum Function of Alternating Sylvester Series

在线全文

学校读者我要写书评

暂无评论

Advances in Pure Mathematics 2012年第6期2卷 459-463页

作者： Huiping Jing luming shen Science College of Hunan Agricultural University Changsha China

The error-sum function of alternating Sylvester series is introduced. Some elementary properties of this function are studied. Also, the hausdorff dimension of the graph of such function is determined.

关键词： Alternating Sylvester Series Error-Sum Function Hausdorff Dimension

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

对外贸易促进城乡共富的理论机制与地区差异

浙江学刊 2024年第3期 163-170页

作者：沈璐敏浙江理工大学经济管理学院杭州310018

随着贸易强国建设的深入推进,对外贸易发展与城乡共富逐渐进入到相互促进的阶段。本文基于2015-2021年的制造业贸易数据,实证检验我国对外贸易发展对省域城乡收入差距的影响。研究发现,我国各省份贸易规模扩大有利于缩小城乡收入差距,... 详细信息

随着贸易强国建设的深入推进,对外贸易发展与城乡共富逐渐进入到相互促进的阶段。本文基于2015-2021年的制造业贸易数据,实证检验我国对外贸易发展对省域城乡收入差距的影响。研究发现,我国各省份贸易规模扩大有利于缩小城乡收入差距,贸易方式优化、贸易结构升级能进一步强化对外贸易带来的城乡收入差距缩小效应。由于贸易方式优化及贸易结构升级的程度不同,相对于“一带一路”沿线国家和美墨加欧盟国家,我国各省份与《区域全面经济伙伴关系协定》国家间的贸易具有更强的城乡收入差距缩小效应;相较于中西部省份,我国东部省份的对外贸易能更大地缩小城乡收入差距。研究结论为我国建设贸易强国和促进城乡共富提供了有益的政策启示。

关键词：国际贸易城乡共富省级面板

Comparison of Two Possible Evolutionary Mechanisms of the 62 tRNA Codon Sequences

在线全文

学校读者我要写书评

暂无评论

Journal of Biomedical Science and Engineering 2017年第4期10卷 172-181页

作者： Fangping Wei Zhenxiong Lan luming shen Bourong Liu Yu Xue Physical Science & Technology College Guangxi University Nanning China College of Computer and Information Engineering Guangxi Teacther Education University Nanning China

The tRNAs were divided into 62 groups based on the codons they carried and networks were constructed. Phylogenetic trees were constructed in parallel and antiparallel directions based on the parameters of these networks. Point mutations were found in the codon sites in the same clusters in the entire parallel and antiparallel phylogenetic trees, whereas there was no evidence of a complementary duplication mechanism in the corresponding antiparallel phylogenetic trees. The codons of isoaccepting tRNAs were found in neighboring clusters or distributed within a very small distance so the codons with only one base difference remained very close, which was perfectly consistent with the hypothesis that a new tRNA gene could be recruited from an isoaccepting group via another point mutation.

关键词： Phylogenetic Trees Point Mutation Template Duplication Network

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于色调分形维数的柑橘糖度和有效酸度检测

农业机械学报 2010年第3期41卷 143-148页

作者：曹乐平温芝元沈陆明湖南生物机电职业技术学院教务处长沙410127 湖南农业大学理学院长沙410128

研究了宫川温州蜜柑糖度及有效酸度的机器视觉检测技术及影响检测精度的因素。对机器视觉系统采集的柑橘图像进行图像裁切、亮度法去图像背景和RGB空间至HSI空间的转换,将柑橘色调范围分割为0°~20°、20°~40°、40°~60°、60°~80°... 详细信息

研究了宫川温州蜜柑糖度及有效酸度的机器视觉检测技术及影响检测精度的因素。对机器视觉系统采集的柑橘图像进行图像裁切、亮度法去图像背景和RGB空间至HSI空间的转换,将柑橘色调范围分割为0°~20°、20°~40°、40°~60°、60°~80°、80°~100°和100°~120°共6个区域,提取各区域色调分形维数,以此作为BP神经网络输入,无损检测宫川温州蜜柑糖度及有效酸度。167个测试样本的检测结果表明：在±1.5°B rix精度范围内糖度正确识别率为66.6175%,在±0.5精度范围内有效酸度正确识别率为73.927 5%。宫川温州蜜柑糖度及有效酸度与果皮色调分形维数之间具有相关性,可用机器视觉检测其糖度及有效酸度。

关键词：柑橘糖度有效酸度机器视觉无损检测色调分形维数

在线全文

学校读者我要写书评

暂无评论

基于类二叉树的虚拟植物分枝结构三维重构

农业工程学报 2011年第11期27卷 151-154页

作者：方逵敬松沈陆明陈演湖南农业大学信息科学技术学院长沙410128

为了有效的提取自然界分枝植物的生长规则,该文在深入研究L系统的基础上,提出了一种基于类二叉树结构的虚拟植物生长三维重构方法。该方法用类二叉树结构来简化分枝植株的生长规则,以L系统描述植株的拓扑结构;对实际树木的仿真结果表明... 详细信息

为了有效的提取自然界分枝植物的生长规则,该文在深入研究L系统的基础上,提出了一种基于类二叉树结构的虚拟植物生长三维重构方法。该方法用类二叉树结构来简化分枝植株的生长规则,以L系统描述植株的拓扑结构;对实际树木的仿真结果表明,该方法能够有效地描述植物的生长规则,为植物生长规则的提取提供了一条新的途径。

关键词：计算机仿真虚拟植物分形类二叉树 L系统三维重构