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A NOTE ON THE S-UNIT EQUATION OVER FUNCTION FIELD
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作者 FENG Keqin(Graduate School at Beijing, University of Science and Technology of China,P.O.Box 3908,Beijing 100039, China) 《Systems Science and Mathematical Sciences》 SCIE EI CSCD 1999年第S1期14-16,共3页
In this note we show that the Mason’s upper bound of deg(u) for S-units u andv satisfying u + v = 1 over function field K = k(C) can be attained for any algebraicallyclosed coefficient field k and for some hyperellip... In this note we show that the Mason’s upper bound of deg(u) for S-units u andv satisfying u + v = 1 over function field K = k(C) can be attained for any algebraicallyclosed coefficient field k and for some hyperelliptic or Artin-Schreier curve C over k withany given genus g≥0. 展开更多
关键词 s-unit equation function fields.
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Study of scalar particles through the Klein–Gordon equation under rainbow gravity effects in Bonnor–Melvin-Lambda space-time
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作者 Faizuddin Ahmed Abdelmalek Bouzenada 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第4期113-125,共13页
In our investigation,we explore the quantum dynamics of charge-free scalar particles through the Klein–Gordon equation within the framework of rainbow gravity,considering the Bonnor–Melvin-Lambda(BML)space-time back... In our investigation,we explore the quantum dynamics of charge-free scalar particles through the Klein–Gordon equation within the framework of rainbow gravity,considering the Bonnor–Melvin-Lambda(BML)space-time background.The BML solution is characterized by the magnetic field strength along the axis of the symmetry direction which is related to the cosmological constantΛand the topological parameterαof the geometry.The behavior of charge-free scalar particles described by the Klein–Gordon equation is investigated,utilizing two sets of rainbow functions:(i)f(χ)=■,h(χ)=1 and(ii)f(χ)=1,h(χ)=1+βХ/2.Here 0<(Х=■)≤1 with E representing the particle's energy,Ep is the Planck's energy,andβis the rainbow parameter.We obtain the approximate analytical solutions for the scalar particles and conduct a thorough analysis of the obtained results.Afterwards,we study the quantum dynamics of quantum oscillator fields within this BML space-time,employing the Klein–Gordon oscillator.Here also,we choose the same sets of rainbow functions and obtain the approximate eigenvalue solution for the oscillator fields.Notably,we demonstrate that the relativistic approximate energy profiles of charge-free scalar particles and oscillator fields get influenced by the topology of the geometry and the cosmological constant.Furthermore,we show that the energy profiles of scalar particles receive modifications from the rainbow parameter and the quantum oscillator fields by both the rainbow parameter and the frequency of oscillation. 展开更多
关键词 quantum fields in curved space-time relativistic wave equations solutions of wave equations BOUND-STATE special functions
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Configuration of propagator method for calculation of electron velocity distribution function in gas under crossed electric and magnetic fields
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作者 Hirotake SUGAWARA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2019年第9期1-18,共18页
This paper presents a self-contained description on the configuration of propagator method(PM)to calculate the electron velocity distribution function(EVDF) of electron swarms in gases under DC electric and magnetic f... This paper presents a self-contained description on the configuration of propagator method(PM)to calculate the electron velocity distribution function(EVDF) of electron swarms in gases under DC electric and magnetic fields crossed at a right angle. Velocity space is divided into cells with respect to three polar coordinates v,θ and f. The number of electrons in each cell is stored in three-dimensional arrays. The changes of electron velocity due to acceleration by the electric and magnetic fields and scattering by gas molecules are treated as intercellular electron transfers on the basis of the Boltzmann equation and are represented using operators called the propagators or Green’s functions. The collision propagator, assuming isotropic scattering, is basically unchanged from conventional PMs performed under electric fields without magnetic fields. On the other hand, the acceleration propagator is customized for rotational acceleration under the action of the Lorentz force. The acceleration propagator specific to the present cell configuration is analytically derived. The mean electron energy and average electron velocity vector in a model gas and SF6 were derived from the EVDF as a demonstration of the PM under the Hall deflection and they were in a fine agreement with those obtained by Monte Carlo simulations. A strategy for fast relaxation is discussed, and extension of the PM for the EVDF under AC electric and DC/AC magnetic fields is outlined as well. 展开更多
关键词 PROPAGATOR method ELECTRON velocity distribution function ELECTRON transport COEFFICIENTS CROSSED electric and magnetic fields MAGNETIZED plasma BOLTZMANN equation
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Solution and stability of mixed type functional equation in non-Archimedean random normed spaces
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作者 张石生 R.SAADATI G.SADEGHI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第5期663-676,共14页
The generalized stability of the Euler-Lagrange quadratic mappings in the framework of non-Archimedean random normed spaces is proved. The interdisciplinary relation among the theory of random spaces, the theory of no... The generalized stability of the Euler-Lagrange quadratic mappings in the framework of non-Archimedean random normed spaces is proved. The interdisciplinary relation among the theory of random spaces, the theory of non-Archimedean spaces, and the theory of functional equations is presented. 展开更多
关键词 generalized Hyers-Ulam stability Euler-Lagrange functional equation nonArchimedean normed space p-adic field
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BSDES IN GAMES,COUPLED WITH THE VALUE FUNCTIONS.ASSOCIATED NONLOCAL BELLMAN-ISAACS EQUATIONS
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作者 郝涛 李娟 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1497-1518,共22页
We establish a new type of backward stochastic differential equations(BSDEs)connected with stochastic differential games(SDGs), namely, BSDEs strongly coupled with the lower and the upper value functions of SDGs, wher... We establish a new type of backward stochastic differential equations(BSDEs)connected with stochastic differential games(SDGs), namely, BSDEs strongly coupled with the lower and the upper value functions of SDGs, where the lower and the upper value functions are defined through this BSDE. The existence and the uniqueness theorem and comparison theorem are proved for such equations with the help of an iteration method. We also show that the lower and the upper value functions satisfy the dynamic programming principle. Moreover, we study the associated Hamilton-Jacobi-Bellman-Isaacs(HJB-Isaacs)equations, which are nonlocal, and strongly coupled with the lower and the upper value functions. Using a new method, we characterize the pair(W, U) consisting of the lower and the upper value functions as the unique viscosity solution of our nonlocal HJB-Isaacs equation. Furthermore, the game has a value under the Isaacs’ condition. 展开更多
关键词 Mc Kean-Vlasov SDE BSDE coupled with the lower and the upper value functions dynamic programming principle mean-field BSDE viscosity solution coupled nonlocal HJB-Isaacs equation Isaacs' condition
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A RANDOM TRANSPORT-DIFFUSION EQUATION 被引量:1
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作者 胡耀忠 《Acta Mathematica Scientia》 SCIE CSCD 2010年第6期2033-2050,共18页
In this paper we study the integral curve in a random vector field perturbed by white noise. It is related to a stochastic transport-diffusion equation. Under some conditions on the covariance function of the vector f... In this paper we study the integral curve in a random vector field perturbed by white noise. It is related to a stochastic transport-diffusion equation. Under some conditions on the covariance function of the vector field, the solution of this stochastic partial differential equation is proved to have moments. The exact p-th moment is represented through integrals with respect to Brownian motions. The basic tool is Girsanov formula. 展开更多
关键词 random vector field chaos expansion random transport-diffusion equation TRACE exponential of quadratic functional of Gaussian field
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<i>L<sub>p</sub></i>-Estimations of Vector Fields in Unbounded Domains
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作者 Alexey V. Kalinin Alla A. Tyukhtina Artem A. Zhidkov 《Applied Mathematics》 2012年第1期45-51,共7页
Some new estimations of scalar products of vector fields in unbounded domains are investigated. Lp-estimations for the vector fields were proved in special weighted functional spaces. The paper generalizes our earlier... Some new estimations of scalar products of vector fields in unbounded domains are investigated. Lp-estimations for the vector fields were proved in special weighted functional spaces. The paper generalizes our earlier results for bounded domains. Estimations for scalar products make it possible to investigate wide classes of mathematical physics problems in physically inhomogeneous domains. Such estimations allow studying issues of correctness for problems with non-smooth coefficients. The paper analyses solvability of stationary set of Maxwell equations in inhomogeneous unbounded domains based on the proved Lp-estimations. 展开更多
关键词 Estimations SCALAR Product Vector field functional Spaces Maxwell equations SOLVABILITY Inhomogeneous Domains
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Approximate energies and thermal properties of a position-dependent mass charged particle under external magnetic fields
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作者 M Eshghi H Mehraban S M Ikhdair 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第6期22-30,共9页
We solve the Schrodinger equation with a position-dependent mass(PDM) charged particle interacted via the superposition of the Morse-plus-Coulomb potentials and is under the influence of external magnetic and Aharo... We solve the Schrodinger equation with a position-dependent mass(PDM) charged particle interacted via the superposition of the Morse-plus-Coulomb potentials and is under the influence of external magnetic and Aharonov–Bohm(AB) flux fields. The nonrelativistic bound state energies together with their wave functions are calculated for two spatially-dependent mass distribution functions. We also study the thermal quantities of such a system. Further, the canonical formalism is used to compute various thermodynamic variables for second choosing mass by using the Gibbs formalism. We give plots for energy states as a function of various physical parameters. The behavior of the internal energy, specific heat, and entropy as functions of temperature and mass density parameter in the inverse-square mass case for different values of magnetic field are shown. 展开更多
关键词 Schr?dinger equation Morse-plus-Coulomb potentials position-dependent mass distribution functions perpendicular magnetic and Aharonov–Bohm flux fields
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On One Possibility of Closuring the Chain of Equations for Statistical Moments in Turbulence Theory
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作者 Edward V. Teodorovich 《Journal of Modern Physics》 2013年第1期56-63,共8页
The paper concerns the problem on statistical description of the turbulent velocity pulsations by using the method of characteristic functional. The equations for velocity covariance and Green’s function, which descr... The paper concerns the problem on statistical description of the turbulent velocity pulsations by using the method of characteristic functional. The equations for velocity covariance and Green’s function, which describes an average velocity response to external force action, have been obtained. For the nonlinear term in the equation for velocity covariance, it has been obtained an exact representation in the form of two terms, which can be treated as describing a momentum transport due to turbulent viscosity and action of effective random forces (within the framework of traditional phenomenological description, the turbulent viscosity is only accounted for). Using a low perturbation theory approximation for high statistical moments, a scheme of closuring the chain of equations for statistical moments is proposed. As the result, we come to a closed set of equations for velocity covariance and Green’s function, the solution to which corresponds to summing up a certain infinite subsequence of total perturbation series. 展开更多
关键词 Random VELOCITY field Statistical DESCRIPTION Characteristic functional CHAIN of equationS for MOMENTS Problem of Closuring
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Bellman Equation for Optimal Processes with Nonlinear Multi-Parametric Binary Dynamic System
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作者 Yakup H. Hacl Kemal Ozen 《Computer Technology and Application》 2012年第1期84-87,共4页
A process represented by nonlinear multi-parametric binary dynamic system is investigated in this work. This process is characterized by the pseudo Boolean objective functional. Since the transfer functions on the pro... A process represented by nonlinear multi-parametric binary dynamic system is investigated in this work. This process is characterized by the pseudo Boolean objective functional. Since the transfer functions on the process are Boolean functions, the optimal control problem related to the process can be solved by relating between the transfer functions and the objective functional. An analogue of Bellman function for the optimal control problem mentioned is defined and consequently suitable Bellman equation is constructed. 展开更多
关键词 Bellman equation bellman function galois field shift operator nonlinear multi-parametric binary dynamic system
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Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1134-1162,共29页
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an... The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles. 展开更多
关键词 ELECTRON POSITRON Wave function Solution Electromagnetic Spin Mass Charge Proof Fundamental Particle Properties Quantum Mechanics Classical Physics Computer 3D Model Schrödinger equation RMS KLEIN GORDON Electric Magnetic Lorentz Invariant Hertzian Vector Point Potential field Density Phase Flow Attraction REPULSION Shell Theorem Ehrenfest VIRIAL Normalization Harmonic Oscillator
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融入非平稳随机场正则化的可控源音频大地电磁法约束反演方法
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作者 戴前伟 郭泸遥 +5 位作者 武赟 熊哲贤 段旦 包中林 吴鸿飞 郝风云 《煤田地质与勘探》 北大核心 2025年第6期246-258,共13页
【目的】可控源音频大地电磁法反演的计算效率和分辨率问题始终是该领域的关键议题。为解决可控源音频大地电磁法反演中计算效率和分辨率不足的问题,特别是传统正则化方法对复杂地质结构估计的过度平滑现象,提出了一种改进的正则化反演... 【目的】可控源音频大地电磁法反演的计算效率和分辨率问题始终是该领域的关键议题。为解决可控源音频大地电磁法反演中计算效率和分辨率不足的问题,特别是传统正则化方法对复杂地质结构估计的过度平滑现象,提出了一种改进的正则化反演方法,旨在更真实地反映地下物性参数的空间分布特性。【方法】采用基于Matérn函数随机偏微分方程的构建法,通过引入矢量场及变程“椭圆”的形状参数,充分考虑地层的倾斜变化和物性分布的非平稳性,构建出满足非平稳假设的模型协方差矩阵,并以此作为正则化约束条件进行反演。通过从反演结果、残差值、视电阻率相对残差及不确定度这4个维度,对比分析了传统最平滑约束方法、基于平稳假设的协方差约束方法以及非平稳协方差约束方法的效果。此外,为验证方法的实际应用效果,将其应用于新疆哈巴河县也尔克曼−金坝金矿勘探的实测数据处理中。【结果】理论模型结果表明,非平稳假设约束下4组试验的残差值介于20.47%~21.29%,优于平稳假设约束(残差值分别为21.25%及22.83%),优于传统最平滑约束方法(残差值为32.46%),且能更真实地反映地质构造特征,以及更清晰地识别地质边界。实测数据结果表明,非平稳假设约束方法在成像效果方面明显优于传统Occam平滑约束方法,数据拟合残差提升达51.47%,显著增强对复杂地质结构的分辨能力,并在一定程度上降低深部区域反演的不确定性,从而有效提升了整体反演结果的可靠性。【结论】基于非平稳假设的Matérn函数正则化反演方法为解决可控源音频大地电磁法反演中的计算效率和分辨率问题提供了一种新的技术手段,对推动地球物理反演技术的发展具有重要意义。 展开更多
关键词 可控源音频大地电磁法 非平稳假设 Matérn协方差函数 随机偏微分方程 矢量场
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基于EMD-FFT方法的双旋流燃烧室非定常特性分析
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作者 王方 张敏琦 +2 位作者 周佳伟 王煜栋 金捷 《海军航空大学学报》 2025年第4期507-518,共12页
通过大涡模拟(Large Eddy Simulation,LES)湍流求解方法和概率密度函数输运方程(Transported Probability Density Function,TPDF)湍流燃烧求解方法结合,对煤油燃料双旋流燃烧室(Gas Turbine Model Combustor,GTMC)进行了模拟,并利用经... 通过大涡模拟(Large Eddy Simulation,LES)湍流求解方法和概率密度函数输运方程(Transported Probability Density Function,TPDF)湍流燃烧求解方法结合,对煤油燃料双旋流燃烧室(Gas Turbine Model Combustor,GTMC)进行了模拟,并利用经验模态分解(Empirical Mode Decomposition,EMD)和快速傅里叶变换(Fast Fourier Transform,FFT)等方法分析了GTMC的温度和速度非定常特性,获得了脉动主频的空间分布。结果显示:空间坐标为(2 cm,0 cm,3 cm)的特征点的温度主频为47和761 Hz;对本征模态函数(Intrinsic Mode Function,IMF)进行显著性分析,能量密度最高的IMF的主频即原始数据的主频;温度脉动主要受湍流流动影响;根据瑞利数场,热-压力激发与抑制区域总是交替出现。 展开更多
关键词 非定常特性 大涡模拟 随机场输运概率密度函数方程湍流燃烧模型 经验模态分解 快速傅里叶变换
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BOS测量密度场泊松方程源项快速计算方法
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作者 张建 张征宇 +4 位作者 杨洋 钱丰学 李小霞 王材钢 罗家杰 《航空学报》 北大核心 2025年第17期59-70,共12页
背景纹影(BOS)是非接触测量流场密度的重要手段,通常采用有限差分法求解泊松方程计算投影密度场,但现有方法计算泊松方程源项(即网格节点上光线偏折角的一阶偏导数)耗时长、突变处精度差。为此,提出基于BOS测量密度场的泊松方程源项快... 背景纹影(BOS)是非接触测量流场密度的重要手段,通常采用有限差分法求解泊松方程计算投影密度场,但现有方法计算泊松方程源项(即网格节点上光线偏折角的一阶偏导数)耗时长、突变处精度差。为此,提出基于BOS测量密度场的泊松方程源项快速计算方法。基于BOS各测量点的光线偏折角数据,创建测量点坐标与光线偏折角场间的哈希函数,旨在快速查找以给定点为中心的局部区域BOS测量点集合及其光线偏折角;建立光线偏折角场中偏折角突变测量点捕捉方法,按突变测量点划分区域,推导并构造区域内偏折角插值型求导公式,基于哈希表和插值型求导公式,分别计算各区域均匀网格节点上光线偏折角的偏导数。仿真试验结果表明:较现有泊松方程源项计算方法,本方法的残差绝对值减小了56.66%,峰值误差减小了75.8%。风洞试验结果表明:较现有方法,本方法解得的空腔模型密度场更精细,加速比为411.85;2 m超风洞“7°(半锥角)的锥柱体模型和某声爆模型”头部微弱激波的测量结果与理论值吻合,激波两侧密度比的最大相对误差为3.9%,流场密度解算正确。因此,本方法提高了密度场测量的速率、精度与微弱激波捕捉能力,工程应用价值大。 展开更多
关键词 密度场重建 光线偏折角 背景纹影 泊松方程 哈希函数
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双线传输线内外电磁场与电磁波的解析计算
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作者 张超 王晓倩 《大学物理》 2025年第2期33-40,50,共9页
为了得出传输模拟信号的双线传输线内外电磁场与电磁波的解析解,该文基于麦克斯韦方程组从TEM波、TM波、TE波的角度对双线传输线内外的电磁场进行了计算.结果表明,在双线传输线内外所传播的电磁波为TM波,双线传输线内电磁场与电磁波的... 为了得出传输模拟信号的双线传输线内外电磁场与电磁波的解析解,该文基于麦克斯韦方程组从TEM波、TM波、TE波的角度对双线传输线内外的电磁场进行了计算.结果表明,在双线传输线内外所传播的电磁波为TM波,双线传输线内电磁场与电磁波的解析解由0阶和1阶复宗量贝塞尔函数构成,双线传输线外电磁场的解析解由0阶复宗量贝塞尔函数和0阶复宗量诺依曼函数构成,同时,该文给出了双线传输线内电磁场的系数与电流的关系.为双线传输线内外电磁场与电磁波的拟合计算、仿真及信号失真、电磁兼容分析提供了依据. 展开更多
关键词 双线传输线 电磁场与电磁波 麦克斯韦方程 复宗量贝塞尔函数 解析计算
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A UNIVERSAL ANALYTIC POTENTIAL-ENERGY FUNCTION BASED ON A PHASE FACTOR 被引量:11
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作者 CFYu KYan DZLiu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2006年第6期455-468,共14页
Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are o... Using a field equation with a phase factor, a universal analytic potential-energy function applied to the interactions between diatoms or molecules is derived, and five kinds of potential curves of common shapes are obtained adjusting the phase factors. The linear thermal expansion coefficients and Young's moduli of eleven kinds of face-centered cubic (fcc) metals - Al, Cu, Ag, etc. are calculated using the potential-energy function; the computational results are quite consistent with experimental values. Moreover, an analytic relation between the linear thermal expansion coefficients and Young's moduli of fcc metals is given using the potential-energy function. Finally, the force constants of fifty-five kinds of diatomic moleculars with low excitation state are computed using this theory, and they are quite consistent with RKR (Rydberg-Klein-Rees) experimental values. 展开更多
关键词 universal potential energy function field equation phase factor derivative renormalization linear thermal expansion coefficient Young's modulus force constant
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ELASTIC CALCULATION OF STRESSES IN RINGS USING AIRY STRESS FUNCTION
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作者 Yicai Sun 1 (Hebei University of Technology, Tianjin 300130) 《Acta Mechanica Solida Sinica》 SCIE EI 2011年第S1期95-106,共12页
Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts ... Stress calculation formulae for a ring have been obtained by using Airy stress function of the plane strain field with the decomposition of the solutions for normal stresses of Airy biharmonic equation into two parts when it is loaded under two opposite inside forces along a diameter. One part should fulfill a constraint condition about normal stress distribution along the circumference at an energy valley to do the minimum work. Other part is a stress residue constant. In order to verify these formulae and the computed results, the computed contour lines of equi-maximal shear stresses were plotted and quite compared with that of photo-elasticity test results. This constraint condition about normal stress distribution along circumference is confirmed by using Greens’ theorem. An additional compression exists along the circumference of the loaded ring, explaining the divorcement and displacement of singularity points at inner and outer boundaries. 展开更多
关键词 elastic circular ring calculation of stresses Airy stress function solving the biharmonic equation plane strain field contour lines of equi-maximal shear stresses a constraint condition about normal stress distribution along circumference
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Photon Structure and Wave Function from the Vector Potential Quantization
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作者 Constantin Meis 《Journal of Modern Physics》 CAS 2023年第3期311-329,共19页
A photon structure is advanced based on the experimental evidence and the vector potential quantization at a single photon level. It is shown that the photon is neither a point particle nor an infinite wave but behave... A photon structure is advanced based on the experimental evidence and the vector potential quantization at a single photon level. It is shown that the photon is neither a point particle nor an infinite wave but behaves rather like a local “wave-corpuscle” extended over a wavelength, occupying a minimum quantization volume and guided by a non-local vector potential real wave function. The quantized vector potential oscillates over a wavelength with circular left or right polarization giving birth to orthogonal magnetic and electric fields whose amplitudes are proportional to the square of the frequency. The energy  and momentum are carried by the local wave-corpuscle guided by the non-local vector potential wave function suitably normalized. 展开更多
关键词 PHOTONS Photon Wave function Vector Potential Quantization Photon Electric and Magnetic fields Photon Structure Wave-Corpuscle Representation Photon “Energy-Vector Potential” equation
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电磁场波动方程的唯一解必然满足Maxwell方程
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作者 闫述 《物理与工程》 2024年第4期11-16,共6页
从Maxwell方程组导出的波动方程的解,代回Maxwell方程中去是否还能得到满足,是电磁场与电磁波课程学习中有时会遇到的问题。本文给出了由自由空间的无源Maxwell方程导出电场和磁场波动方程的过程,然后根据均匀平面波的定义,求得波动方... 从Maxwell方程组导出的波动方程的解,代回Maxwell方程中去是否还能得到满足,是电磁场与电磁波课程学习中有时会遇到的问题。本文给出了由自由空间的无源Maxwell方程导出电场和磁场波动方程的过程,然后根据均匀平面波的定义,求得波动方程的通解。证明这些解满足Maxwell散度方程,但由于含有与源相关的待定常数,故无法判定它们是否满足Maxwell旋度方程。验证某个矢量函数是否满足波动方程和Maxwell方程的习题,并不具有波动方程的解不一定满足Maxwell方程的含义。教材中关于满足波动方程的场量不一定满足Maxwell方程的阐述,指的是未获得波动方程唯一性解的情形;所提出的由波动方程求出一个场量后,再由Maxwell方程求出另一场量的解题方法,目的是当无源时可获得更多的信息,有源时避免复杂源项降低求解难度。可以证明,电偶极子电场和磁场波动方程的唯一解,满足Maxwell方程组中的全部方程。根据电磁场的唯一性定理和宏观电磁场时空分布的确定性,无论求解空间有源还是无源,只要能够获得波动方程的唯一解,这些解必然满足Maxwell方程。 展开更多
关键词 电磁场波动方程 MAXWELL方程 矢量函数 满足 唯一解 唯一性定理
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气压湿度对空气隙绝缘特性的影响研究 被引量:2
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作者 苏梦函 安韵竹 +3 位作者 赵文龙 胡元潮 李海涛 黄涛 《高压电器》 CAS CSCD 北大核心 2024年第1期78-86,共9页
外界环境条件影响以空气为介质的电力设备外绝缘性能,为了研究空气放电的物理特性,文中基于Boltzmann方程研究空气中电子与分子碰撞的微观过程,计算分析气压、湿度对空气隙绝缘性能的影响规律。结果表明,温度为300 K,气压为1.0 atm(1 at... 外界环境条件影响以空气为介质的电力设备外绝缘性能,为了研究空气放电的物理特性,文中基于Boltzmann方程研究空气中电子与分子碰撞的微观过程,计算分析气压、湿度对空气隙绝缘性能的影响规律。结果表明,温度为300 K,气压为1.0 atm(1 atm=101 kPa)时,空气相对湿度的升高会改变电子能量分布函数和电子输运参数。相对湿度每升高30%,电子平均能量下降约0.2 eV,约化电子迁移率下降约0.25×10^(23)(V∙m∙s)^(-1),约化电子扩散系数下降约0.2×10^(24)(m∙s)^(-1),空气相对湿度从0%升高到30%,临界击穿场强升高486 V/cm,空气相对湿度从30%升高到60%,临界击穿场强升高729 V/cm,空气隙绝缘性能增强;温度为300 K,相对湿度为0%时,气压每升高0.2 atm,临界击穿场强升高约6 kV/cm,空气隙绝缘性能增强。 展开更多
关键词 湿度 气压 玻尔兹曼方程 电子能量分布函数 临界击穿场强
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