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本文给出了单摆运动非线性微分方程的精确解,并得到了单摆运动周期与初始条件的关系。当初始条件满足一定关系时,单摆的运动状态并不由初始条件唯一确定,而有两种可能,因此状态空间出现分支点,这是非线性方程解的特征. 相似文献
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基于MATLAB下对单摆实验中大摆角问题的讨论 总被引:1,自引:0,他引:1
借助MATLAB计算软件,研究无阻尼状态下单摆的大摆角运动,给出了任意摆角下单摆运动周期的精确解。同时利用MATLAB函数库中的ode45函数,求解出大摆角下的单摆的运动方程及其运动规律,为单摆实验中大摆角问题的讲解提供了较好的教学辅助手段。 相似文献
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用单摆测量重力加速度是大学普通物理实验中的一个基础实验,测量的核心问题是如何精确的测量单摆周期,常有秒表法、光电探测器、霍耳位置传感器等方法.这些方法各有优缺点,但无法测出单摆在摆动过程中的运动情况.本文设计的基于红外微位移传感器的精密测量装置,不仅可以对单摆周期进行精确测 相似文献
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研究和分析有阻尼单摆的运动方程,应用近似法方程时发现存在冲击波解并精确求解.同时结合有阻尼单摆的相图分析冲击波解存在的物理意义. 相似文献
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用线性插值法求单摆运动周期的近似解 总被引:6,自引:1,他引:5
利用线性插值的方法,提出了一个任意摆角条件下的单摆运动周期的近似公式.并利用Mathematica软件将该公式与精确解进行了比较,还与其他近似公式进行了对比.结果表明,该公式的近似程度相当好. 相似文献
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无阻尼单摆运动微分方程是一种具有物理背景的非线性常微分方程,研究其精确解和解法是非线性科学中的一个重要内容.在F展开法的基础上,应用反正切分式变换正弦函数方法,并引入Riccati辅助方程,得到了4种无阻尼单摆方程精确解的结果.达到了丰富此类方程求解技巧和精确解的目的.总结得出此类方程应用反正切分式变换方法具有一定普适性的结论. 相似文献
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非线性系统受迫振动的周期解 总被引:1,自引:1,他引:0
理论上采用近似法求解,并用数学软件作图,分析和讨论了单摆自由振动的非等时性以及非线性受迫振动周期解与线性受迫振动稳态解的重要差别. 相似文献
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对用单摆测重力加速度实验中单摆周期的测定进行了研究,给出了一种基于电子秒表的自动测量单摆周期的可靠装置,改进了传统单摆周期测量的不足,提高了测量单摆周期的精度. 相似文献
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Naoyuki Amemiya Kengo Miyamoto Shun-ichi Murasawa Hideki Mukai Kazuya Ohmatsu 《Physica C: Superconductivity and its Applications》1998,310(1-4):30-35
AC losses in Bi-2223 superconducting tapes carrying AC transport current and/or exposed to DC or AC magnetic field are calculated with a numerical model based on the finite element method. Superconducting property is given by the E–J characteristic represented by a power law using equivalent conductivity. First, transport loss and magnetization loss are calculated numerically and compared with measured values. The calculated losses almost agree with the measured losses. Frequency dependencies of calculated and measured transport losses are compared with each other. Next, the influence of DC external magnetic field on the transport loss is studied. DC external magnetic field reduces n that is an exponent in the power law connecting resistivity and current density. The numerically calculated transport loss increases with increasing DC magnetic field. Finally, the total loss of superconducting tape carrying AC transport current in AC magnetic field is calculated. In the perpendicular magnetic field, the calculated total loss is lager than the sum of the transport loss and the magnetization loss, while they almost agree with each other in the parallel magnetic field. 相似文献
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Molecular dynamics simulation combined with an embedded atom method (EAM) potential was applied to the calculation of the
specific heat and the diffusion coefficient for superheated and undercooled liquid copper and nickel as functions of temperature.
The system contains 108,000 atoms. The calculated results show that the enthalpy increases linearly with the rise of temperature.
There are no breaks at their melting temperatures of 1356 and 1726 K. It is found that the calculated specific heats of Cu
and Ni are 32.75 and 36.11 J/mol/K respectively. The calculated mean square displacements increase linearly with calculated
time. The diffusion coefficients are exponentially dependent on temperature. Moreover, the calculated results are in good
agreement with the reported experimental results for the specific heat and diffusion coefficient. 相似文献
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在超重核区(Z≥104)使用文献[7—9]给出的3组参数应用Viola-Seaborg公式计算了α衰变寿命,所得结果与实验值进行比较,发现其结果与实验值相差较大。为此,利用最小二乘法分别在重核区和超重核区重新对参数进行了拟合,得到的计算结果与实验值相比符合得较理想,尤其是由超重核得到的参数的结果非常理想。 相似文献
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An analytical approach for simultaneously determining an inelastic mean free path (IMFP), a surface excitation parameter (SEP) and a differential SEP (DSEP) with absolute units was applied for the analysis of absolutely measured reflection electron energy loss spectra for Au. The IMFP, SEP and DSEP in Au for 300-3000 eV electrons are successfully obtained. The obtained DSEPs show a reasonable agreement with those theoretically calculated. The present SEPs were compared with those calculated by several empirical equations, revealing that the present SEPs are close to those calculated using the Oswald's equation. The IMFPs for Au determined by the present analysis were compared with those calculated by the TPP-2M predictive equation, revealing that the present IMFPs are in fairly good agreement with those calculated by the TPP-2M equation. The results confirmed that the present approach is effective for experimentally determining the SEP, DSEP, and IMFP for electrons in solids. 相似文献
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Yu. É. Zevatskiy 《Technical Physics》2006,51(3):378-382
The terms of ions and atoms are calculated with a method based on the Bohr model. The ionization potentials of helium-like, lithium-like, and beryllium-like ions are calculated as functions of the nuclear charge and electron quantum numbers. The results calculated are in satisfactory agreement with experimental data. The accuracy of the method is found to rise with the nuclear charge of ions. 相似文献
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王义 《原子与分子物理学报》2000,17(2):359-362
以GGA-LAPW冷能计算为基础,应用经典统计理论计算了铁的Hugoniot性质,包括:P-V曲线、P-T曲线、热容、Grueneisen参数,计算结果基本上与实验符合。 相似文献
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Hu Chi 《International Journal of Infrared and Millimeter Waves》2003,24(11):1999-2006
Semicircular groove guide is a kind of waveguide for millimeter waves. In this paper, a conformal mapping technique is used to analyze it. Several semicircular groove guides are calculated with the method. It is shown that their cutoff wavelength calculated by the method are very close to those calculated by the transverse resonance method. 相似文献