On the chaotic behavior of the non-ideal vibrating systems

The paper discusses the chaotic behavior of a vibrating structure coupled to an energy source. The structural response of this system may act like energy sink under certain conditions so that a part of the energy supplied by the source is spend to vibrate the structure rather than increasing the drive speed, according to the Sommerfeld effect [1]. The energy source is influenced by the response of the system and consequently, the system exhibits jumps at critical values of the energy source. The system mimics a disappearance of the energy in the resonance regions which can affect the stability of the system, sending it to chaos [2-4]. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the classical descriptions of the quantum phenomena in the harmonic oscillator and in a charged particle under the coulomb force

In this work it is shown that the intrinsic phenomenon (the quantization of the energy) that appears in the first and simple systems studied initially by the quantum theory as the harmonic oscillator and the movement of a charged particle under the Coulomb force, can be obtained from the study of dissipative systems. In others words, we show that this phenomenon of the quantization of the energy of a particle which moves as an harmonic oscillator and which loses and wins energy can be obtained via a classical system of equations. The same also applies to the phenomena of the quantization of the energy of a charged particle which moves under the Coulomb force and which loses and wins energy.     

On the classical descriptions of the quantum phenomena in the harmonic oscillator and in a charged particle under the coulomb force

In this work it is shown that the intrinsic phenomenon (the quantization of the energy) that appears in the first and simple systems studied initially by the quantum theory as the harmonic oscillator and the movement of a charged particle under the Coulomb force, can be obtained from the study of dissipative systems. In others words, we show that this phenomenon of the quantization of the energy of a particle which moves as an harmonic oscillator and which loses and wins energy can be obtained via a classical system of equations. The same also applies to the phenomena of the quantization of the energy of a charged particle which moves under the Coulomb force and which loses and wins energy.     

有向图反能量的一个注记

有向图的反能量是指有向图的反邻接矩阵的能量.本文利用有向图的运算构造出了几类有向图,它们中的每一个都满足有向图的反能量等于其底图的能量.部分回答了Adiga等人在文[The skew energy of a digraph,Linear Algebra Appl.,2010,432:1825-1835]中提出的一个公开问题.     

Domain branching in uniaxial ferromagnets: asymptotic behavior of the energy

In this article we analyze the ground state energy of a ferromagnetic bulk sample with strong uniaxial anisotropy in a regime featuring domain branching. We derive the convergence of the micromagnetic energy towards a sharp interface energy in the spirit of Γ-limits. Then we use this convergence to rigorously justify the notion of a minimal energy per cross-section area. Compared to known results, the scaling bounds for the minimal energy are improved to an asymptotic equality.     

带有风能的智能电网多周期买电策略研究

本文研究带有风能随机供给的智能电网中传统能源的多周期买电问题,假设存在一个能源运营商集中负责智能电网传统能源的购买和消费。通过构建并求解动态规划模型,找到能源运营商在风能供给不确定性下的传统能源最优多周期买电策略。在最优买电策略下,能源运营商只有在当期电价足够小时才购买传统能源,其买电量与风能分布、价格信息和时间信息有关。在实际数据的基础之上,提供详实的数值实验对比研究了本文的最优买电策略和其他两种策略(实践中只考虑风能估计的策略和放弃利用风能的策略)在最小化总成本方面的效果,并验证了本文的最优买电策略在真实风能数据中的鲁棒性。     

基于SPA-TOPSIS方法的能源结构优化程度评价

以能源低碳化发展为基础,从社会经济发展程度、能源规划合理程度、环境和谐程度三个准则层入手,构建能源结构优化程度评价指标体系。运用改进惯性权重的PSO算法确定评价体系权重,并基于SPA-TOPSIS法构建能源结构优化程度评价模型,对30个省、自治区、直辖市的区域能源结构优化程度进行实证研究。实证结果表明:区域社会经济发展水平对能源结构优化程度有直接影响,且各区域能源结构优化程度差异较大,总体呈现“东高西低”的格局;清洁能源消费占比、原煤消费占比、烟尘排放等因素对能源结构优化程度影响显著。     

Long time dynamics of the 3D radial NLS with the combined terms

In this paper,we study the scattering and blow-up dichotomy result of the radial solution to nonlinear Schrodinger equation(NLS) with the combined terms iu_t+△u=-|u|~4u+|4|~(p-1)u,1+4/3p5 in energy space H~1(R~3).The threshold energy is the energy of the ground state W of the focusing,energy critical NLS,which means that the subcritical perturbation does not affect the determination of threshold,but affects the scattering and blow-up dichotomy result with subcritical threshold energy.This extends algebraic perturbation in a previous work of Miao,Xu and Zhao[Comm.Math.Phys.,318,767-808(2013)]to all mass supercritical,energy subcritical perturbation.     

Convergent geometric integrator for the Landau-Lifshitz-Gilbert equation in micromagnetics

We consider a lowest-order finite element scheme for the Landau-Lifshitz-Gilbert equation (LLG) which describes the dynamics of micromagnetism. In contrast to previous works, we examine LLG with a total magnetic field which is induced by several physical phenomena described in terms of exchange energy, anisotropy energy, magnetostatic energy, and Zeeman energy. In our numerical scheme, the highest-order term which stems from the exchange energy, is treated implicitly, whereas the remaining energy contributions are computed explicitly. Therefore, only one sparse linear system has to be solved per time-step. The proposed scheme is unconditionally convergent to a global weak solution of LLG. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

能源强度变动的多因素分解方法研究

为更加全面、准确地度量影响能源强度变动的因素,在分析相关研究文献的基础上,提出包含产业结构份额、部门能源效率份额和能源结构份额的三因素几何均值能源强度分解模型,该模型不仅能够将能源消费结构对能源强度的影响从产业结构和部门效率份额中分离出来,而且克服了当数据集合中出现零值时,现有处理方法产生较大误差的缺点,提供了一种精度较高的多因素能源强度分解方法.     

A scaling and energy equality preserving approximation for the 3D Navier-Stokes equations in the finite energy case

We discuss a new model (inspired by the work of Vishik and Fursikov) approximating the 3D Navier-Stokes equations, which preserves the scaling as in the Navier-Stokes equations and thus allows the study of self-similar solutions. Using some energy estimates and Leray’s limiting process, we show the existence of a solution of this model in the finite energy case, and the energy equality and inequality fulfilled by it. This approximation can be shown to converge to the Navier-Stokes equations using a mild approach based on the approximated pressure, and the solution satisfies Scheffer’s local energy inequality, an essential tool for proving Caffarelli, Kohn and Nirenberg’s regularity criterion. We also give a partial result of self-similarity satisfied by the approximated solution in the infinite energy case.     

The model reference control for the four-dimensional energy supply-demand system

The four-dimensional energy supply-demand system is a nonlinear complex system. The purpose of this paper is to introduce the model reference control method in the four-dimensional energy supply-demand system. By establishing the energy supply-demand reference system, controlling the imports in the four-dimensional energy supply-demand system to the ideal state.     

A direct method to calculate the energy evolution of a turbulent flow

The classical configuration of the power spectrum of a homogeneous turbulent flow provides a functional relation between energy and enstrophy which may be used to find the evolution of energy in the intermediate stages of finite time and viscosity to which the usual asymptotic arguments do not apply. The method has a minimal computational cost compared with the direct numerical integration of the whole Navier–Stokes system. It is applied here to study the energy evolution both theoretically and numerically, obtaining the minima of energy compatible with the power spectra as well as the rate of decay of the energy towards them. The results may be useful to study the compatibility of the Kolmogorov and Kraichnan spectra with the observed energy evolution of a turbulent flow.     

Fourier Integrals, Special Functions, and the Semicontinuity Phenomenon

For a real weighted homogeneous hypersurface germ, we consider elliptic deformations and related special functions. Singularities of these special functions are characterized by some rational numbers called energy exponents. We apply the residue mapping to the corresponding Fourier integrals and give a geometric interpretation of the energy exponents in the terms of the volume of the associated Lagrangian manifold. The energy exponents are calculated for a series of examples. Two conjectures concerning the energy exponents are discussed.     

Long term forecasting of energy demand in the developing countries

Forecasting long-term energy demand should be an important component of energy planning in developing countries. Traditional aggregated econometric metods are not well adapted and technico-economic approaches which look in more details at the determinants of energy demand seem better suited. This paper outlines a possible approach to the modeling of energy demand in developing countries.     

我国低碳经济发展机制的系统动力学建模

在分析了低碳经济系统复杂结构特征及动态反馈关系的基础上,建立了低碳经济系统动力学模型并进行了仿真模拟,研究表明:技术进步、产业调节政策对降低碳排放具有显著影响,提高能源效率是低碳发展的重要举措,制度建设是低碳发展的基础设施.从政策层面上,应通过调整能源结构,发展新能源和可再生能源;改变经济增长方式,调整产业结构,优先发展高新科技产业、服务业等第三产业;引导消费方式的改变,减少能源消耗,实现低碳发展.     

坑口电厂低碳经济发展系统动力学仿真研究

通过分析坑口电厂低碳经济系统的复杂结构特征和动态反馈机制,建立了坑口电厂低碳经济系统动力学模型,描述系统内部各要素之间的相互关系,并以平煤集团坑口电厂为例,对不同发展方案下的坑口电厂低碳经济系统进行仿真模拟.结果表明:科技投资、环保投资、能源利用率、能源消费结构等因素是影响坑口电厂低碳经济发展的关键因素;可以通过优化能源消费结构,提高煤矸石消耗比例;增加科技投资和环保投资,提高能源利用和转换效率,降低污染物和二氧化碳排放量,从而达到高效率、低能耗、低排放的低碳经济发展模式.     

Application of the string method to compute minimum energy paths for a chain of bi-stable elements using the finite element method and molecular dynamics

Activated processes are frequently found in solid state mechanics. The energy landscape of such processes show a non-convex behaviour, and therefore the computation of energy barriers between two stable minima is of importance. Such barriers are revealed by computing minimum energy paths. The string method is a simple and efficient algorithm to move curves over an energy landscape and to identify minimum energy paths. A hierarchical two-scale model recently introduced to the literature (molecular dynamics coupled with the finite element method) is used in this paper to investigate the string method in a model phase transition in a copper single crystal. To do so, bi-stable elements are constructed and the energetic behaviour of a two-elements chain is investigated. We identify successfully the minimum energy path between two local stable minima of the chain and demonstrate thereby the performance of the string method applied to a complex multiscale model. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the minimax spherical designs

Distributing points on a (possibly high-dimensional) sphere with minimal energy is a long-standing problem in and outside the field of mathematics. This paper considers a novel energy function that arises naturally from statistics and combinatorial optimization, and studies its theoretical properties. Our result solves both the exact optimal spherical point configurations in certain cases and the minimal energy asymptotics under general assumptions. Connections between our results and the L1-principal component analysis and quasi-Monte Carlo methods are also discussed.