期刊文献+
共找到177篇文章
< 1 2 9 >
每页显示 20 50 100
Description of inverse energy cascade in homogeneous isotropic turbulence using an eigenvalue method 被引量:1
1
作者 Feng LIU Hantao LIU +1 位作者 Hongkai ZHAO Pengfei LYU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2021年第9期1233-1246,共14页
A description of inverse energy cascade(from small scale to large scale)in homogeneous isotropic turbulence is introduced by using an eigenvalue method.We show a special isotropic turbulence,in which the initial condi... A description of inverse energy cascade(from small scale to large scale)in homogeneous isotropic turbulence is introduced by using an eigenvalue method.We show a special isotropic turbulence,in which the initial condition is constructed by reversing the velocity field in space,i.e.,the time-reversed turbulence.It is shown that the product of eigenvalues of the rate-of-strain tensor can quantitatively describe the backward energy transfer process.This description is consistent to the velocity derivative skewness Sk.However,compared with Sk,it is easier to be obtained,and it is expected to be extended to anisotropic turbulence.Furthermore,this description also works for the resolved velocity field,which means that it can be used in engineering turbulent flows.The description presented here is desired to inspire future investigation for the modeling of the backward energy transfer process and lay the foundation for the accurate prediction of complex flows. 展开更多
关键词 inverse energy cascade homogeneous isotropic turbulence eigenvalue method turbulence model
在线阅读 下载PDF
Analysis of Energy Eigenvalue in Complex Ginzburg–Landau Equation
2
作者 高继华 肖骐 +2 位作者 谢玲玲 张昕昕 杨海涛 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第6期717-722,共6页
In this paper, we consider the two-dimensional complex Ginzburg–Landau equation(CGLE) as the spatiotemporal model, and an expression of energy eigenvalue is derived by using the phase-amplitude representation and the... In this paper, we consider the two-dimensional complex Ginzburg–Landau equation(CGLE) as the spatiotemporal model, and an expression of energy eigenvalue is derived by using the phase-amplitude representation and the basic ideas from quantum mechanics. By numerical simulation, we find the energy eigenvalue in the CGLE system can be divided into two parts, corresponding to spiral wave and bulk oscillation. The energy eigenvalue of spiral wave is positive, which shows that it propagates outwardly; while the energy eigenvalue of spiral wave is negative, which shows that it propagates inwardly. There is a necessary condition for generating a spiral wave that the energy eigenvalue of spiral wave is greater than bulk oscillation. A wave with larger energy eigenvalue dominates when it competes with another wave with smaller energy eigenvalue in the space of the CGLE system. At the end of this study, a tentative discussion of the relationship between wave propagation and energy transmission is given. 展开更多
关键词 complex Ginzburg–Landau equation energy eigenvalue spiral wave bulk oscillation
原文传递
Energy eigenvalues from an analytical transfer matrix method
3
作者 何英 张凡明 +1 位作者 杨艳芳 李春芳 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第4期50-55,共6页
A detailed procedure based on an analytical transfer matrix method is presented to solve bound-state problems. The derivation is strict and complete. The energy eigenvalues for an arbitrary one-dimensional potential c... A detailed procedure based on an analytical transfer matrix method is presented to solve bound-state problems. The derivation is strict and complete. The energy eigenvalues for an arbitrary one-dimensional potential can be obtained by the method. The anharmonic oscillator potential and the rational potential are two important examples. Checked by numerical techniques, the results for the two potentials by the present method are proven to be exact and reliable. 展开更多
关键词 analytical transfer matrix method energy eigenvalues bound state one-dimensional potential
原文传递
Computing Dark Energy and Ordinary Energy of the Cosmos as a Double Eigenvalue Problem
4
作者 Mohamed S. El Naschie 《Journal of Modern Physics》 2015年第4期384-395,共12页
We compute the dark energy and ordinary energy density of the cosmos as a double Eigenvalue problem. In addition, we validate the result using two different theories. The first theory is based on Witten’s 11 dimensio... We compute the dark energy and ordinary energy density of the cosmos as a double Eigenvalue problem. In addition, we validate the result using two different theories. The first theory is based on Witten’s 11 dimensional spacetime and the second is based on ‘tHooft’s fractal renormalization spacetime. In all cases, the robust result is E(O) = mc2/22 for ordinary energy and E(D) = mc2(21/22) for dark energy. Adding E(O) to E(D) we obtain Einstein’s famous equation which confirms special relativity, although it adds a quantum twist to its interpretation. This new interpretation is vital because it brings relativity theory in line with modern cosmological measurements and observations. In particular, we replace calculus by Weyl scaling in all computation which is essentially transfinite discrete. 展开更多
关键词 DOUBLE eigenvalues WEYL Scaling Magueijo-Smolin energy Formula Dark energy Einstein’s Relativity E-INFINITY Theory
在线阅读 下载PDF
What Will Happen, If Zero SpinParticle Possesses Spin Rotational Construction, With Non-Zero Eigenvalues Of Spin Angular Momentum?
5
作者 ShaoXu Ren 《Journal of Modern Physics》 2016年第16期2257-2265,共9页
There is no any spin rotational construction for zero spin particle, Casimir operator and the thired component of zero spin particle areandrespectively. Further, there are no spin interactions between zero spin partic... There is no any spin rotational construction for zero spin particle, Casimir operator and the thired component of zero spin particle areandrespectively. Further, there are no spin interactions between zero spin particle and other spin particles. This paper shows: in Spin Topological Space, STS [1], the third component of zero spin particle possesses non-zero eigenvalues besides original zero value, this leads to a miraculous spin interaction phenomenon between zero spin particle and other spin particles. In STS, zero spin particle could "dissolve other spin particles", degrade the values of their Casimir operator, and decay these spin particles into other forms of spin particle. 展开更多
关键词 zero spin particle non-Hermitian matrix non-zero eigenvalues Casimir operator the third component Spin Topological Space STS binding energy of spin particles
在线阅读 下载PDF
QUANTUM PHENOMENON OF THE ENERGY DENSITY OF A HARMONIC MAP TO A SPHERE 被引量:3
6
作者 周振荣 《Acta Mathematica Scientia》 SCIE CSCD 2003年第1期41-45,共5页
This paper proves that if the energy density of a harmonic map to a unit sphere varies between two successive half eigenvalues, then it must be one of them. Applying this result to the Gaussian maps of some submanifol... This paper proves that if the energy density of a harmonic map to a unit sphere varies between two successive half eigenvalues, then it must be one of them. Applying this result to the Gaussian maps of some submanifolds, the quantum phenomena of the square length of the second fundamental forms of these submanifolds is obtained. Some related topics are discussed in this note. 展开更多
关键词 energy density eigenvalue the second fundamental form
在线阅读 下载PDF
Energy Spectrum for a Short-Range 1/r Singular Potential with a Non-Orbital Barrier Using the Asymptotic Iteration Method 被引量:1
7
作者 Abdullah J. Sous Abdulaziz D. Alhaidari 《Journal of Applied Mathematics and Physics》 2016年第1期79-85,共7页
Using the asymptotic iteration method, we obtain the S-wave solution for a short-range three-parameter central potential with 1/r singularity and with a non-orbital barrier. To the best of our knowledge, this is the f... Using the asymptotic iteration method, we obtain the S-wave solution for a short-range three-parameter central potential with 1/r singularity and with a non-orbital barrier. To the best of our knowledge, this is the first attempt at calculating the energy spectrum for this potential, which was introduced by H. Bahlouli and A. D. Alhaidari and for which they obtained the “potential parameter spectrum”. Our results are also independently verified using a direct method of diagonalizing the Hamiltonian matrix in the J-matrix basis. 展开更多
关键词 Short-Range Three-Parameter Central Potential Asymptotic Iteration Method Potential Parameter Spectrum Method J-Matrix Diagonalizing Method energy eigenvalues
在线阅读 下载PDF
Generalization for Laplacian energy
8
作者 LIU Jian-ping LIU Bo-lian 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2009年第4期443-450,共8页
Let G be a simple graph with n vertices and m edges. Let λ1, λ2,…, λn, be the adjacency spectrum of G, and let μ1, μ2,…, μn be the Laplacian spectrum of G. The energy of G is E(G) = n∑i=1|λi|, while the ... Let G be a simple graph with n vertices and m edges. Let λ1, λ2,…, λn, be the adjacency spectrum of G, and let μ1, μ2,…, μn be the Laplacian spectrum of G. The energy of G is E(G) = n∑i=1|λi|, while the Laplacian energy of G is defined as LE(G) = n∑i=1|μi-2m/n| Let γ1, γ2, ~ …, γn be the eigenvalues of Hermite matrix A. The energy of Hermite matrix as HE(A) = n∑i=1|γi-tr(A)/n| is defined and investigated in this paper. It is a natural generalization of E(G) and LE(G). Thus all properties about energy in unity can be handled by HE(A). 展开更多
关键词 energy (of matrix) Hermite matrix eigenvalue
在线阅读 下载PDF
ADAPTIVE EIGENFREQUENCY ANALYSIS BY IMPROVED r-AND h-ADAPTIVE FINITE ELEMENT METHOD BASED ON PERTURBATION AND ELEMENT ENERGY RATIO
9
作者 Liu Hanbing Gong Guoqing Wei Yuan 《Acta Mechanica Solida Sinica》 SCIE EI 2001年第4期349-356,共8页
A new adaptive technique of r-and h-version for vibration problemsutilizing the matrix per- turbation theory and element energy ratiois proposed. In structural vibration analysis, through the r-conver-gence adaptvie f... A new adaptive technique of r-and h-version for vibration problemsutilizing the matrix per- turbation theory and element energy ratiois proposed. In structural vibration analysis, through the r-conver-gence adaptvie finite element process, mesh optimization can berealized. In the light of the judgement on the changes in themagnitude of the element energy ratio, local refinement can beachieved in the process of h- convergence adaptive finite element sothat more accurate finite element solutions can be obtained with asfew meshes as possible. Many numerical examples are given and theproposed approach is shown to be feasible and effective. 展开更多
关键词 r-and h-adaptive FEM iterative perturbation element energy ratio eigenvalue problems
在线阅读 下载PDF
The Distance Energy of Circulant Graphs
10
作者 ZHOU Hou-qing 《Chinese Quarterly Journal of Mathematics》 2018年第3期233-239,共7页
For a connected graph G, the distance energy of G is a recently developed energytype invariant, defined as the sum of absolute values of the eigenvalues of the distance matrix G. A graph is called circulant if it is C... For a connected graph G, the distance energy of G is a recently developed energytype invariant, defined as the sum of absolute values of the eigenvalues of the distance matrix G. A graph is called circulant if it is Cayley graph on the circulant group, i.e., its adjacency matrix is circulant. In this note, we establish lower bounds for the distance energy of circulant graphs. In particular, we discuss upper bound of distance energy for the 4-circulant graph. 展开更多
关键词 DISTANCE eigenvalue DISTANCE energy CIRCULANT GRAPH
在线阅读 下载PDF
Small-World Networks with Unitary Cayley Graphs for Various Energy Generation
11
作者 C.Thilag P.B.Sarasija 《Computer Systems Science & Engineering》 SCIE EI 2023年第6期2773-2782,共10页
Complex networks have been a prominent topic of research for several years,spanning a wide range of fields from mathematics to computer science and also to social and biological sciences.The eigenvalues of the Seidel ... Complex networks have been a prominent topic of research for several years,spanning a wide range of fields from mathematics to computer science and also to social and biological sciences.The eigenvalues of the Seidel matrix,Seidel Signless Laplacian matrix,Seidel energy,Seidel Signless Laplacian energy,Maximum and Minimum energy,Degree Sum energy and Distance Degree energy of the Unitary Cayley graphs[UCG]have been calculated.Low-power devices must be able to transfer data across long distances with low delay and reliability.To overcome this drawback a small-world network depending on the unitary Cayley graph is proposed to decrease the delay and increase the reliability and is also used to create and analyze network communication.Small-world networks based on the Cayley graph have a basic construction and are highly adaptable.The simulation result shows that the small-world network based on unitary Cayley graphs has a shorter delay and is more reliable.Furthermore,the maximum delay is lowered by 40%. 展开更多
关键词 Seidel energy Seidel Signless Laplacian eigenvalues Distance degree energy Unitary Cayley graphs
在线阅读 下载PDF
Minimum Covering RandićEnergy of a Graph
12
作者 M. R. Rajesh Kanna R. Jagadeesh 《Advances in Linear Algebra & Matrix Theory》 2016年第4期116-131,共17页
Randi&cacute;energy was first defined in the paper [1]. Using minimum covering set, we have introduced the minimum covering Randi&cacute;energy RE<sub>C</sub> (G) of a graph G in this paper. This p... Randi&cacute;energy was first defined in the paper [1]. Using minimum covering set, we have introduced the minimum covering Randi&cacute;energy RE<sub>C</sub> (G) of a graph G in this paper. This paper contains computation of minimum covering Randi&cacute;energies for some standard graphs like star graph, complete graph, thorn graph of complete graph, crown graph, complete bipartite graph, cocktail graph and friendship graphs. At the end of this paper, upper and lower bounds for minimum covering Randi&cacute;energy are also presented. 展开更多
关键词 Minimum Covering Set Minimum Covering Randi&cacute MATRIX Minimum Covering Randi&cacute eigenvalueS Minimum Covering Randi&cacute energy
在线阅读 下载PDF
On the Non-Common Neighbourhood Energy of Graphs
13
作者 Ahmad N. Al-Kenani Anwar Alwardi Omar A. Al-Attas 《Applied Mathematics》 2015年第8期1183-1188,共6页
In this paper, we introduce a new type of graph energy called the non-common-neighborhood energy ,?,?NCN-energy for some standard graphs is obtained and an upper bound for ?is found when G is a strongly regular graph.... In this paper, we introduce a new type of graph energy called the non-common-neighborhood energy ,?,?NCN-energy for some standard graphs is obtained and an upper bound for ?is found when G is a strongly regular graph. Also the relation between common neigh-bourhood energy and non-common neighbourhood energy of a graph is established. 展开更多
关键词 NCN-eigenvalues (of Graph) NCN-energy (of Graph) NCN-Adjacency Matrix (of Graph)
在线阅读 下载PDF
TLD耗能结构系列风振响应的简明封闭解
14
作者 李创第 余洋城 +1 位作者 杨雪峰 葛新广 《桂林理工大学学报》 北大核心 2025年第1期51-56,共6页
针对使用调谐液体阻尼器(TLD)的耗能建筑结构在Davenport风速谱下的系列响应计算复杂不利于实际应用的问题,提出了一种基于频率响应特征值函数二次正交化的简明解法。基于TLD的集中质量法获得耗能结构在风振作用下的运动方程;通过复模... 针对使用调谐液体阻尼器(TLD)的耗能建筑结构在Davenport风速谱下的系列响应计算复杂不利于实际应用的问题,提出了一种基于频率响应特征值函数二次正交化的简明解法。基于TLD的集中质量法获得耗能结构在风振作用下的运动方程;通过复模态法和一阶微分方程的虚拟激励法得到耗能结构的系列风振响应的频域解;基于频率响应特征值函数的二次正交化获得TLD耗能结构在Davenport风速谱下结构功率谱函数的简明解;利用谱矩的定义得到TLD耗能结构风振响应的0~2阶谱矩及结构加速度方差的简明封闭解。通过算例将本文方法同虚拟激励法比较验证了其正确性,并且计算结果不受积分步长影响,相较于虚拟激励法在计算效率上更高,更有助于实际工程应用。 展开更多
关键词 TLD耗能结构 Davenport风速谱 频率响应特征值函数 二次正交化 风振响应简明封闭解
在线阅读 下载PDF
考虑光伏调频作用的电力系统频率动态特性分析 被引量:1
15
作者 石鹏 王永灿 +6 位作者 王曦 白珈于 陈保瑞 左佳鑫 李振垚 王雪一 甘德强 《电力自动化设备》 北大核心 2025年第5期110-117,184,共9页
随着新能源渗透率的不断提高,我国电力系统呈现高不确定性和低惯量特性。针对含光伏的电力系统,对其频率响应特性展开研究。建立计及光伏的电力系统频率线性化模型,推导得到频率时域解析解;将模型的主导特征值算式近似解耦为三次方程,... 随着新能源渗透率的不断提高,我国电力系统呈现高不确定性和低惯量特性。针对含光伏的电力系统,对其频率响应特性展开研究。建立计及光伏的电力系统频率线性化模型,推导得到频率时域解析解;将模型的主导特征值算式近似解耦为三次方程,并说明频率响应特性由主导特征值决定;根据主导特征值的近似解,推导频率指标的解析表达式,证明调速器下垂控制和光伏频率控制会增加系统阻尼但不会改变系统惯量。以10机39节点系统为仿真算例,将所建模型与系统频率响应模型、平均系统频率模型进行对比,结果验证了所建模型的准确性,并分析了调速器下垂系数和光伏频率控制参数对系统频率响应特性的影响。 展开更多
关键词 电力系统 一次调频 频率响应特性 新能源发电 光伏 主导特征值
在线阅读 下载PDF
制氢系统对双馈风机串补系统次同步振荡特性的影响
16
作者 鲁亚楠 徐涛 刘泽楠 《发电技术》 2025年第4期715-726,共12页
【目的】规模化风电机组的并网运行增加了系统发生次同步振荡(sub-synchronous oscillation,SSO)的风险,针对此问题,深入分析了制氢系统对风电系统SSO特性的影响。【方法】首先,搭建双馈风电系统、串补输电系统和制氢系统模型;然后,在... 【目的】规模化风电机组的并网运行增加了系统发生次同步振荡(sub-synchronous oscillation,SSO)的风险,针对此问题,深入分析了制氢系统对风电系统SSO特性的影响。【方法】首先,搭建双馈风电系统、串补输电系统和制氢系统模型;然后,在此基础上,根据制氢系统电解槽内部热动力和电化学动态特性,在PSCAD/EMTDC仿真平台建立制氢装置的电磁暂态模型;最后,将其加入到双馈风电经串补外送系统中进行时域仿真分析。【结果】制氢系统在特定的控制参数下会参与到系统的次同步振荡中,制氢系统加入到风电远距离输送系统能在一定程度上缓解并网系统SSO,从而提供一种解决SSO问题的新思路。【结论】制氢系统的投入提高了风氢耦合并网系统的阻尼,改善了系统稳定性。 展开更多
关键词 新能源 氢能 风电机组 制氢系统 次同步振荡(SSO) 双馈风机 串联补偿 特征值分析法 时域仿真
在线阅读 下载PDF
基于代表性片段的新能源汽车多城市工况曲线构建优化方法
17
作者 王义博 刘海江 魏冉 《机械制造与自动化》 2025年第1期270-275,共6页
为了提高新能源汽车在多种城市工况下的车速循环测试效率,对3个不同地区的新能源汽车工况曲线提出一种筛选方法并利用代表性片段对3个城市工况曲线重构。用速度、加速度等能耗相关性大的特征参数计算原始曲线的特征值并划分运动片段,计... 为了提高新能源汽车在多种城市工况下的车速循环测试效率,对3个不同地区的新能源汽车工况曲线提出一种筛选方法并利用代表性片段对3个城市工况曲线重构。用速度、加速度等能耗相关性大的特征参数计算原始曲线的特征值并划分运动片段,计算片段间的欧式距离并进行相似性排序;用能耗特征信息与相似性排序结果筛选出具有代表性的片段;用少量代表性片段组合出与原始曲线具有能耗一致性的新曲线。结果表明:新曲线在曲线特征值、速度-加速度联合概率分布、续航里程仿真以及实车台架测试中,均能反映原始曲线的特征,且构建新曲线使用的片段数量远少于原曲线,提高了测试效率。 展开更多
关键词 新能源汽车 工况曲线构建 片段筛选 特征值计算 曲线能耗仿真 聚类分析
在线阅读 下载PDF
一类单圈图的最小sum-connectivity能量
18
作者 赵可 朱芳 赵璇 《重庆理工大学学报(自然科学)》 北大核心 2025年第9期240-248,共9页
定义C_(g)∪S_(t)为将一个圈C_(g)中的某个顶点与一个星图S_(t)中的某个顶点相连后构造出的具有n个顶点的单圈图。图G的sum-connectivity矩阵S(G)=(s_(ij))_(n×n)是一n阶矩阵,其中,若顶点v_(i)与顶点v_(j)邻接,则s_(ij)=1/√d_(G)(... 定义C_(g)∪S_(t)为将一个圈C_(g)中的某个顶点与一个星图S_(t)中的某个顶点相连后构造出的具有n个顶点的单圈图。图G的sum-connectivity矩阵S(G)=(s_(ij))_(n×n)是一n阶矩阵,其中,若顶点v_(i)与顶点v_(j)邻接,则s_(ij)=1/√d_(G)(v_(i))+d_(G)(v_(j)),若v_(i)与点v_(j)不邻接,或i=j,则s_(ij)=0。图G的sum-connectivity能量定义为sum-connectivity矩阵特征值的绝对值之和。考虑了该类单圈图中的sum-connectivity能量的极小值问题。根据sum-connectivity能量的定义及其性质得到4种图变换,同时得到该类单圈图sum-connectivity能量的变化规律,最后得到S_(n)^(3)在该类单圈图中具有最小的sum-connectivity能量,其中S_(n)^(3)表示圈C_(3)上某个顶点连接n-3条悬挂边的单圈图。 展开更多
关键词 单圈图 特征多项式 特征值 sum-connectivity能量
在线阅读 下载PDF
Smallest Eigenvalues Based Logarithmic Derivative Method for Computing Dominant Oscillation Modes in Large-scale Power Systems
19
作者 Linguang Wang Xiaorong Xie +2 位作者 Wenkai Dong Yong Mei Aoyu Lei 《Journal of Modern Power Systems and Clean Energy》 2025年第3期747-756,共10页
With the rapid integration of renewable energy,wide-band oscillations caused by interactions between power electronic equipment and grids have emerged as one of the most critical stability issues.Existing methods are ... With the rapid integration of renewable energy,wide-band oscillations caused by interactions between power electronic equipment and grids have emerged as one of the most critical stability issues.Existing methods are usually studied for local power systems with around one hundred nodes.However,for a large-scale power system with tens of thousands of nodes,the dimension of transfer function matrix or the order of characteristic equation is much higher.In this case,the existing methods such as eigenvalue analysis method and impedance-based method have difficulty in computation and are thus hard to utilize in practice.To fill this gap,this paper proposes a novel method named the smallest eigenvalues based logarithmic derivative(SELD)method.It obtains the dominant oscillation modes by the logarithmic derivative of the k-smallest eigenvalue curves of the sparse extended nodal admittance matrix(NAM).An oscillatory stability analysis tool is further developed based on this method.The effectiveness of the method and the tool is validated through a local power system as well as a large-scale power system. 展开更多
关键词 Large-scale power system renewable energy integration k-smallest eigenvalue eigenvalue analysis smallest eigenvalues based logarithmic derivative(SELD)method oscillatory stability analysis
原文传递
基于导纳稳定容量的新能源并网强度评估
20
作者 吴林林 邓晓洋 +2 位作者 郑佳杰 梁以宁 郑乐 《电力系统自动化》 北大核心 2025年第13期43-51,共9页
随着新型电力系统中新能源渗透率逐渐升高,电力系统的动态行为发生显著变化,变流器等电力电子设备并网后的系统稳定性分析日益复杂。文中基于元件的特征值灵敏度分析方法提出了考虑变流器控制细节差异的并网强度评估指标。首先,对多馈... 随着新型电力系统中新能源渗透率逐渐升高,电力系统的动态行为发生显著变化,变流器等电力电子设备并网后的系统稳定性分析日益复杂。文中基于元件的特征值灵敏度分析方法提出了考虑变流器控制细节差异的并网强度评估指标。首先,对多馈入系统进行全系统阻抗建模,分析了特征值对具体导纳变化的灵敏度;其次,从新能源并网点变流器导纳最大变化程度的物理本质出发,定义了导纳稳定容量,导纳稳定容量捕获了系统所有元件的动力学特性,可以描述系统的抗干扰能力和新能源并网点的电网强度;最后,通过单变流器连无穷大系统和改进的14母线系统验证了所提指标的有效性。 展开更多
关键词 新型电力系统 小信号 特征值 导纳稳定容量 灵敏度 变流器 并网强度 新能源
在线阅读 下载PDF
上一页 1 2 9 下一页 到第
使用帮助 返回顶部