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A New Class of Harmonic Univalent Functions by the Generalized Salagean Operator 被引量:6
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作者 LI Shuhai LIU Peide 《Wuhan University Journal of Natural Sciences》 CAS 2007年第6期965-970,共6页
A complex-valued harmonic functions that are univalent and sense preserving in the unit disk U can be written in the form f = h + g^-, where h and g are analytic in U. We define and investigate a new class SHPλ(α... A complex-valued harmonic functions that are univalent and sense preserving in the unit disk U can be written in the form f = h + g^-, where h and g are analytic in U. We define and investigate a new class SHPλ(α,β)by generalized Salagean operator of harmonic univalent functions. We give sufficient coefficient conditions for normalized harmonic functions in the class SHPλ(α,β) These conditions are also shown to be necessary when the coefficients are negative. This leads to distortion bounds and extreme points. 展开更多
关键词 harmonic function Salagean operator extreme point distortion bounds
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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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基于SOM神经网络的电网谐波源检测与定位研究 被引量:7
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作者 马立新 徐聪 《控制工程》 CSCD 北大核心 2018年第5期709-715,共7页
谐波对电网及其中正在运行的设备都会产生较大影响,且电网中谐波源的位置和所注入谐波大小具有较大的随机性和非线性,为了准确确定电网中谐波的产生位置,提出了一种基于SOM神经网络的电网谐波源检测与定位方法。该方法主要将电网中与公... 谐波对电网及其中正在运行的设备都会产生较大影响,且电网中谐波源的位置和所注入谐波大小具有较大的随机性和非线性,为了准确确定电网中谐波的产生位置,提出了一种基于SOM神经网络的电网谐波源检测与定位方法。该方法主要将电网中与公共连接点(PCC)连接的各母线及各类型负载单独运行时的负载特征为训练样本建立判断网络,并以此为标准对谐波源位置进行判断,最终确定谐波源所在位置。通过基于Matlab2014a仿真平台实验证明,将实时运行过程中在PCC点所测得的负载特征加入判断网络中,即可完成对于谐波源位置的判断,经过多组待测负载检测结果表明此判断网络具有较高的判断准确率。因此,该方法对于电网中谐波源的检测及定位可取得较好效果,具有一定的工程应用价值。 展开更多
关键词 谐波源 SOM神经网络 PCC点 负载特征 定位
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COMPUTING HARMONIC MAPS AND CONFORMAL MAPS ON POINT CLOUDS
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作者 Tianqi Wu Shing-Tung Yau 《Journal of Computational Mathematics》 SCIE CSCD 2023年第5期879-908,共30页
We use a narrow-band approach to compute harmonic maps and conformal maps for surfaces embedded in the Euclidean 3-space,using point cloud data only.Given a surface,or a point cloud approximation,we simply use the sta... We use a narrow-band approach to compute harmonic maps and conformal maps for surfaces embedded in the Euclidean 3-space,using point cloud data only.Given a surface,or a point cloud approximation,we simply use the standard cubic lattice to approximate itsϵ-neighborhood.Then the harmonic map of the surface can be approximated by discrete harmonic maps on lattices.The conformal map,or the surface uniformization,is achieved by minimizing the Dirichlet energy of the harmonic map while deforming the target surface of constant curvature.We propose algorithms and numerical examples for closed surfaces and topological disks.To the best of the authors’knowledge,our approach provides the first meshless method for computing harmonic maps and uniformizations of higher genus surfaces. 展开更多
关键词 harmonic maps conformal maps point clouds
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逆变器谐波注入引发电池包单体电芯电压跳变问题研究
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作者 陈石人 黄勇 +2 位作者 肖曦 杨凡 舒朝雷 《汽车工程师》 2023年第11期19-24,共6页
针对某纯电动汽车在下线路试中高荷电状态(SOC)下出现制动失速、低SOC情况下满油门加速出现顿挫的问题,经分析确认是逆变器软件谐波注入电流信号参数不合理引发整车电网络系统的谐振,从而导致单体电芯电压跳变所致。对整车电网络系统谐... 针对某纯电动汽车在下线路试中高荷电状态(SOC)下出现制动失速、低SOC情况下满油门加速出现顿挫的问题,经分析确认是逆变器软件谐波注入电流信号参数不合理引发整车电网络系统的谐振,从而导致单体电芯电压跳变所致。对整车电网络系统谐振问题进行分析,建立整车电网络模型,计算谐振点,并优化了谐波注入策略,实车验证结果表明,采用优化策略时单体电芯电压跳变较小,且未引发新的NVH问题。 展开更多
关键词 谐波注入 基尔霍夫电流定律 谐振点 整车电网络 纯电动汽车
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Modeling GPS multipath effect based on spherical cap harmonic analysis 被引量:4
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作者 郭金运 李国伟 +1 位作者 孔巧丽 王书阳 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1874-1879,共6页
Most GPS positioning errors can be eliminated or removed by the differential technique or the modeling method,but the multipath effect is a special kind of system or gross error,so it is difficult to be simulated or e... Most GPS positioning errors can be eliminated or removed by the differential technique or the modeling method,but the multipath effect is a special kind of system or gross error,so it is difficult to be simulated or eliminated.In order to improve the accuracy of GPS positioning,the single-epoch pseudorange multipath effects at GPS station were calculated,and firstly modeled based on the spherical cap harmonic(SCH),which is the function of satellite longitude and latitude with the robust method.The accuracy of the kinematic point positioning technique was improved by correcting pseudorange observations with the multipath effect calculated by the SCH model,especially in the elevation direction.The spherical cap harmonic can be used to model the pseudorange multipath effect. 展开更多
关键词 GPS multipath effect spherical cap harmonic kinematic point positioning
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High-accuracy thermodynamic properties to the melting point from ab initio calculations aided by machine-learning potentials
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作者 Jong Hyun Jung Prashanth Srinivasan +1 位作者 Axel Forslund Blazej Grabowski 《npj Computational Materials》 SCIE EI CSCD 2023年第1期2310-2321,共12页
Accurate prediction of thermodynamic properties requires an extremely accurate representation of the free-energy surface.Requirements are twofold—first,the inclusion of the relevant finite-temperature mechanisms,and ... Accurate prediction of thermodynamic properties requires an extremely accurate representation of the free-energy surface.Requirements are twofold—first,the inclusion of the relevant finite-temperature mechanisms,and second,a dense volume–temperature grid on which the calculations are performed.A systematic workflow for such calculations requires computational efficiency and reliability,and has not been available within an ab initio framework so far.Here,we elucidate such a framework involving direct upsampling,thermodynamic integration and machine-learning potentials,allowing us to incorporate,in particular,the full effect of anharmonic vibrations.The improved methodology has a five-times speed-up compared to state-of-the-art methods.We calculate equilibrium thermodynamic properties up to the melting point for bcc Nb,magnetic fcc Ni,fcc Al,and hcp Mg,and find remarkable agreement with experimental data.A strong impact of anharmonicity is observed specifically for Nb.The introduced procedure paves the way for the development of ab initio thermodynamic databases. 展开更多
关键词 harmonic point prediction
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谐波齿轮柔轮啮合点周向刚度的理论分析及仿真 被引量:3
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作者 陈晓霞 吴鸿雁 +2 位作者 牛洪波 姚云鹏 邢静忠 《西安交通大学学报》 EI CAS CSCD 北大核心 2021年第10期184-192,共9页
为揭示柔轮结构对其啮合点周向刚度的影响规律,提升谐波齿轮的传动刚度,提出柔轮啮合点周向刚度的理论计算方法。该算法首先将周向力引起的柔轮啮合点变形拆分为筒体变形和齿体变形,分别推导周向力作用下柔轮杯底、光筒、齿圈和圆弧过... 为揭示柔轮结构对其啮合点周向刚度的影响规律,提升谐波齿轮的传动刚度,提出柔轮啮合点周向刚度的理论计算方法。该算法首先将周向力引起的柔轮啮合点变形拆分为筒体变形和齿体变形,分别推导周向力作用下柔轮杯底、光筒、齿圈和圆弧过渡部分的扭转变形及渐开线轮齿的弯曲和齿根转动的理论公式,并基于周向位移等效折算柔轮啮合点周向刚度;然后建立包含工艺结构及渐开线齿廓等真实结构的杯型柔轮实体单元有限元模型,对未装配变形柔轮模型和波发生器作用下产生装配变形的柔轮模型分别施加周向力,获得柔轮筒体和齿体的负载变形。有限元仿真结果表明:杯底对柔轮筒体的扭转刚度的影响最大,齿体弯曲在齿体变形中的占比最大;装配变形增加了柔轮筒体的刚度,使其负载周向变形减小了约10%;减小齿廓压力角、增大变位系数和齿宽,可提高齿体刚度;柔轮筒体和齿体变形的理论解与有限元解的偏差分别为1.3%和2.2%;啮合点周向刚度的理论解与有限元解的相对偏差为-5%,验证了该算法的有效性。 展开更多
关键词 谐波齿轮传动 柔轮 啮合点 周向刚度 有限元仿真
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Symmetry of the Point Spectrum of Infinite Dimensional Hamiltonian Operators and Its Applications 被引量:1
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作者 Hua WANG Alatancang Jun-jie HUANG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2012年第1期149-156,共8页
This paper studies the symmetry, with respect to the real axis, of the point spectrum of the upper triangular infinite dimensional Hamiltonian operator H. Note that the point spectrum of H can be described as σp(H)... This paper studies the symmetry, with respect to the real axis, of the point spectrum of the upper triangular infinite dimensional Hamiltonian operator H. Note that the point spectrum of H can be described as σp(H) = σp (A) U σp1 (-A*). Using the characteristic of the set σp1(-A*), we divide the point spectrum σp (d) of A into three disjoint parts. Then, a necessary and sufficient condition is obtained under which σp1(-A*) and one part of σp(A) are symmetric with respect to the real axis each other. Based on this result, the symmetry of σp(H) is completely given. Moreover, the above result is applied to thin plates on elastic foundation, plane elasticity problems and harmonic equations. 展开更多
关键词 infinite dimensional Hamiltonian operator point spectrum SYMMETRY thin plate on elasticfoundation plane elasticity problem harmonic equation
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一种舰船轴频电场信号源强度计算方法 被引量:1
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作者 李国栋 姜润翔 +1 位作者 孙兆龙 刘琪 《探测与控制学报》 CSCD 北大核心 2022年第4期28-34,共7页
为了有效计算不同谐波频率轴频电场信号的等效源强度,在对轴频电场、轴电流特性分析的基础上,结合“空气海水海床”三层介质中点电荷模型的计算公式,反演出轴频电场包络信号的等效源强度,再根据水下电场谐波信号的幅值和相位反推出各个... 为了有效计算不同谐波频率轴频电场信号的等效源强度,在对轴频电场、轴电流特性分析的基础上,结合“空气海水海床”三层介质中点电荷模型的计算公式,反演出轴频电场包络信号的等效源强度,再根据水下电场谐波信号的幅值和相位反推出各个谐波对应的源强度。利用不同阴极保护状态下的缩比船模试验数据对所提方法的有效性进行检验,试验结果表明,所提方法能够较好地实现对谐波信号源强度的准确计算,0.7倍船宽深度向1.0倍、1.5倍船宽深度换算时,谐波信号的频谱相对误差小于12%。 展开更多
关键词 舰船 轴频电场 谐波信号 点电荷 反演
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梅涅劳斯定理和塞瓦定理的应用 被引量:2
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作者 徐颖 胡岩伟 《高师理科学刊》 2001年第1期7-10,14,共5页
通过对梅涅劳斯定理和塞瓦定理在解题中的应用研究 ,证明共线点与共点线以及著名定理 .
关键词 调和共轭点 交比 截线 梅涅劳斯定理 塞瓦定理 平面几何 共线点 共点线
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城市变压器中性点地电流特性分析与抑制策略 被引量:1
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作者 陈爽 方翰 +3 位作者 石一辉 李航 朱劲力 王丹 《变压器》 2022年第11期28-34,共7页
通过傅里叶变换,对比分析不同时间段内变压器中性点地电流特征以及各次谐波随时间的变化过程。对经由变压器中性点侵入电网的谐波电流的传递特性开展分析研究,搭建基于变压器、线路实际参数的仿真模型,并研究了谐波次数、末端负荷、变... 通过傅里叶变换,对比分析不同时间段内变压器中性点地电流特征以及各次谐波随时间的变化过程。对经由变压器中性点侵入电网的谐波电流的传递特性开展分析研究,搭建基于变压器、线路实际参数的仿真模型,并研究了谐波次数、末端负荷、变压器类型等对谐波地电流传递的影响。提出了基于无源滤波的抑制策略,以应对更加频繁的地电流入侵现象。 展开更多
关键词 电力变压器 地电流 谐波 中性点 直流偏磁
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谐波误差对N(N>3)点均布测量圆参数的影响 被引量:2
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作者 张德芬 张国雄 《计量学报》 CSCD 北大核心 1997年第1期23-27,共5页
用严密的数学理论和误差理论,推导出了在三坐标测量机上采用多点均布测量圆零件的圆心位置和半径时,选择不同的测量点数,谐波误差对测量结果产生不同的影响。
关键词 谐波 误差 三坐标测量机 误差理论 测量
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准同步谐波分析的DSP实现 被引量:1
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作者 韩建超 杨北革 李芙英 《继电器》 CSCD 北大核心 2005年第18期49-52,66,共5页
介绍一种DSP准同步谐波分析系统。系统硬件选用主从式双处理器结构,主处理器(单片机)负责人机交互及DSP的Bootloader等,从处理器(DSP芯片)专门负责数据处理;软件采用定点机浮点化运算,自定义浮点类型简化运算,提高运算速度和有效位数,... 介绍一种DSP准同步谐波分析系统。系统硬件选用主从式双处理器结构,主处理器(单片机)负责人机交互及DSP的Bootloader等,从处理器(DSP芯片)专门负责数据处理;软件采用定点机浮点化运算,自定义浮点类型简化运算,提高运算速度和有效位数,系统在谐波分析中利用准同步算法,提高非正弦周期信号非同步采样情况下电网参数运算的准确度。系统成功应用于光电式高压计量装置,通过仿真试验,基波准确度优于0.1%,11次以下的谐波准确度优于2%。具有良好的实用价值和拓展性能。 展开更多
关键词 谐波分析 准同步算法 DSP 浮点化
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二次曲线主轴方程的解析法建模研讨 被引量:1
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作者 宋占奎 《陕西教育学院学报》 2007年第1期98-100,共3页
根据既是共轭又互相垂直的直径对有心二次曲线(双曲线椭圆)进行建模研究,建立了有心二次曲线和类似建立了无心二次曲线(抛物线)主轴方程的模型,推证得知,任意无穷远点关于二次曲线的极线都是直径。而且它们都通过中心,有心二次曲线有一... 根据既是共轭又互相垂直的直径对有心二次曲线(双曲线椭圆)进行建模研究,建立了有心二次曲线和类似建立了无心二次曲线(抛物线)主轴方程的模型,推证得知,任意无穷远点关于二次曲线的极线都是直径。而且它们都通过中心,有心二次曲线有一对主轴,无心二次曲线仅一个主轴。 展开更多
关键词 主轴 极点 极线 对称轴 调和共轭 共轭直径 无穷远点 无穷远直线
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Analytical Approach for the Systematic Research of the Periodic Ferroresonant Solutions in the Power Networks
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作者 Fathi Ben Amar Rachid Dhifaoui 《Energy and Power Engineering》 2011年第4期450-477,共28页
Ferroresonance is a complex and little known electrotechnical phenomenon. This lack of knowledge means that it is voluntarily considered responsible for a number of unexplained destructions or malfunctioning of equipm... Ferroresonance is a complex and little known electrotechnical phenomenon. This lack of knowledge means that it is voluntarily considered responsible for a number of unexplained destructions or malfunctioning of equipment. The mathematical framework most suited to the general study of this phenomenon is the bifurcation theory, the main tool of which is the continuation method. Nevertheless, the use of a continuation process is not devoid of difficulties. In fact, to continue the solutions isolats which are closed curves, it is necessary to know a solution belonging to this isolated curve (isolat) to initialise the continuation method. The principal contribution of this article is to develop an analytical method allowing systematic calculation of this initial solution for various periodic ferroresonant modes (fundamental, harmonic and subharmonic) appearing on nonlinear electric system. The approach proposed uses a problem formulation in the frequency domain. This method enables to directly determine the solution in steady state without computing of the transient state. When we apply this method to the single-phase ferroresonant circuits (series and parallels configurations), we could easily calculate an initial solution for each ferroresonant mode that can be established. Knowing this first solution, we show how to use this analytical approach in a continuation technique to find the other solutions. The totality of the obtained solutions is represented in a plane where the abscissa is the amplitude of the supply voltage and the ordinate the amplitude of the system’s state variable (flux or voltage). The curve thus obtained is called “bifurcation diagram”. We will be able to then obtain a synthetic knowledge of the possible behaviors of the two circuits and particularly the limits of the dangerous zones of the various periodic ferroresonant modes that may appear. General results related to the series ferroresonance and parallel ferroresonance, obtained numerically starting from the theoretical and real cases, 展开更多
关键词 Transformer FERRORESONANCE Fundamental MODE harmonic MODE SUBharmonic MODE Fractional MODE Isolat Limit point BIFURCATION DANGEROUS Zone
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On Simplified Models for Dynamics of Pointlike Objects
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作者 Marijan Ribarič +4 位作者 Luka Š terš 《Journal of Applied Mathematics and Physics》 2021年第8期1853-1869,共17页
<strong>Motivation:</strong> We study the asymptotic-type dynamics of various real pointlike objects that one models by a variety of differential equations. Their response to an external force one defines ... <strong>Motivation:</strong> We study the asymptotic-type dynamics of various real pointlike objects that one models by a variety of differential equations. Their response to an external force one defines solely by the trajectory of a single point. Its velocity eventually stops changing after cessation of the external force. The response of their acceleration to the long-term external force is slow and possibly nonlinear. <strong>Objective:</strong> Our objective is to present technique for making simplified models for the long-term dynamics of pointlike objects whose motion interacts with the surroundings. In the asymptotic-type long-term dynamics, the time variable <em>t</em> ∈ (<em>t<sub>m</sub></em>, +∞) and<em> t<sub>m</sub></em> > 0 is large, say <img src="Edit_6f0f7522-7319-4b30-a451-0453ff0f75d3.bmp" alt="" />! <strong>Method:</strong> We apply Taylor series expansion to differential equations to model the acceleration of pointlike object whose response to the long-term external force is not instantaneous and possibly nonlinear. <strong>Results:</strong> We make simplified models for the long-term dynamics of pointlike objects by Taylor polynomials in time derivatives of the external force. <strong>Application:</strong> We interpret the relativistic Lorentz-Abraham-Dirac equation as an equation for modeling the long-term dynamics, where <em>t</em> ≥ <em>t<sub>m</sub></em> <span style="white-space:nowrap;">&#8811;</span> 0. This interpretation resolves the conceptual and usage controversy surrounding its troublesome application to determine the trajectory of a radiating charged particle, thus contributing to the development of more adequate modeling of physical phenomena. 展开更多
关键词 point Mass Long-Term Dynamics harmonic Oscillator Drag Force Lorentz-Abraham-Dirac Equation Taylor Series Expansion
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A CLASS OF HARMONIC STARLIKE FUNCTIONS WITH RESPECT TO SYMMETRIC POINTS ASSOCIATED WITH WRIGHT GENERALIZED HYPERGEOMETRIC FUNCTION
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作者 M.K. Aouf R.M. El-Ashwah +1 位作者 A. Shamandy S.M. El-Deeb 《Analysis in Theory and Applications》 2012年第4期363-376,共14页
Making use of Wright operator we introduce a new class of complex-valued harmonic functions with respect to symmetric points which are orientation preserving, univalent and starlike. We obtain coefficient conditions, ... Making use of Wright operator we introduce a new class of complex-valued harmonic functions with respect to symmetric points which are orientation preserving, univalent and starlike. We obtain coefficient conditions, extreme points, distortion bounds, and convex combination. 展开更多
关键词 harmonic UNIVALENT Wright operator symmetric point
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谐振动的坐标原点和势能零点的选择 被引量:1
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作者 邱荒逸 《高师理科学刊》 2007年第5期78-80,共3页
用数学、力学的一般讨论方法,说明谐振动就是动、势能在平衡位置附近相互转化,并用算例重点论证了对于谐振系统,其坐标系原点和势能零点一般只能选在这个谐振动系统的平衡位置上,而非一般力学问题可任意选取.为解决物理教学上的难点,提... 用数学、力学的一般讨论方法,说明谐振动就是动、势能在平衡位置附近相互转化,并用算例重点论证了对于谐振系统,其坐标系原点和势能零点一般只能选在这个谐振动系统的平衡位置上,而非一般力学问题可任意选取.为解决物理教学上的难点,提供一个选择方案. 展开更多
关键词 简谐振动 势能 平衡位置
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找准理论与实践的结合点——高师音乐教育专业和声学教改实验谈 被引量:1
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作者 姜丽新 王殿玉 《齐齐哈尔师范高等专科学校学报》 2010年第1期131-132,共2页
在高师和声学教学中,从培养学生应用能力出发,努力探求理论与实践的结合点。探索和声教学与写作实践相结合的教学方法,抛弃"纸上谈兵",综合各学科知识,努力实现理论与实践的统一,知识与能力的统一,以建设一门学术性、师范性... 在高师和声学教学中,从培养学生应用能力出发,努力探求理论与实践的结合点。探索和声教学与写作实践相结合的教学方法,抛弃"纸上谈兵",综合各学科知识,努力实现理论与实践的统一,知识与能力的统一,以建设一门学术性、师范性兼备的实用型课程。 展开更多
关键词 和声学 理论与实践的统一 结合点
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