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1.
For the accurate extraction of cavity decay time, a selection of data points is supplemented to the weighted least square method. We derive the expected precision, accuracy and computation cost of this improved method, and examine these performances by simulation. By comparing this method with the nonlinear least square fitting(NLSF) method and the linear regression of the sum(LRS) method in derivations and simulations, we find that this method can achieve the same or even better precision, comparable accuracy, and lower computation cost. We test this method by experimental decay signals. The results are in agreement with the ones obtained from the nonlinear least square fitting method. 相似文献
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X射线荧光光谱理论α系数法测定古青铜钱币中的铅铜锡 总被引:2,自引:0,他引:2
毛振伟 《光谱学与光谱分析》1999,19(5):738-741
本将Lachance-traill(L-T)方程理论α系数法应用于古青铜钱币中的Pb,Cu,Sn分析,并与基本参数法和标样法的结果进行了比较。由于本法和模拟标样法都是从基本参数法演变来的,使用的标样是一样的,三种方法计算结果数据比较接近。本法计算速度快,效率高,但对标样的依赖性较大。 相似文献
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利用泽尼克系数求取衍射光栅的分辨本领 总被引:1,自引:0,他引:1
光栅分辨本领检测设备的焦距通常达几米甚至十几米,采用直接测量法难度大、成本高,利用衍射波前间接求取光栅分辨本领是解决该问题的有效途径之一。在光栅光谱成像傅里叶变换理论基础上,建立了利用泽尼克多项式拟合系数求解衍射光栅分辨本领的归一化模型,揭示了光栅衍射波前与分辨本领的求取关系,提出了依据泽尼克多项式拟合系数求取衍射光栅分辨本领的新方法。根据该方法实测了一块衍射光栅的分辨本领,并与直接测量法进行对比测试。结果表明该方法误差小于4.42%,降低了分辨本领的测试难度,是衍射光栅分辨本领求取的有效手段,应用于ZYGO干涉仪等仪器中,通过简单的波前测试即可得到定量的衍射光栅分辨本领指标。 相似文献
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泡泡布点方法及其并行性 总被引:2,自引:0,他引:2
针对无网格和有限元方法中的布点需求,借鉴分子动力学方法和泡泡网格化方法的思想和处理技术,提出一种单纯的布点方法--泡泡布点方法.将区域内的点看作有相互作用力的泡泡,通过动态模拟得到高质量的点集,模拟中不需要网格连接.算例显示,生成的均匀点集和非均匀点集都具有很好的结构和渐进性,并对复杂区域具有很好的适应性.同时由于相互作用力的局部性,该布点方法类似于短程作用的分子动力学模拟,拥有潜在的并行性.通过初步的并行算例,验证了其并行化的可行性. 相似文献
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In this paper, we improve some key steps in the homogeneous balance method (HBM), and propose a modified homogeneous balance
method (MHBM) for constructing multiple soliton solutions of the nonlinear partial differential equation (PDE) in a unified
way. The method is very direct and primary; furthermore, many steps of this method can be performed by computer. Some illustrative
equations are investigated by this method and multiple soliton solutions are found. 相似文献
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A new method is proposed to determine the optimal embedding
dimension from a scalar time series in this paper. This method
determines the optimal embedding dimension by optimizing the
nonlinear autoregressive prediction model parameterized by the
embedding dimension and the nonlinear degree. Simulation results
show the effectiveness of this method. And this method is applicable
to a short time series, stable to noise, computationally efficient,
and without any purposely introduced parameters. 相似文献
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An adaptive VQ method used on interferential multi-spectral image lossless compression 总被引:1,自引:0,他引:1
In this paper, a high efficient adaptive LBG VQ (vector quantization) method is proposed, which is an improved version of the expansion LBG VQ method [1] (proposed in 2009)and exploits the shortest distance from a point to line segment. Moreover, the proposed method is used on the lossless compression of LASIS (Large Aperture Static Imaging Spectrometer) interferential multi-spectral images. Compared with the expansion LBG VQ method proposed in 2009, the experimental results showed that the adaptive LBG VQ method improved the compression performance obviously. And the experiment also showed that when using these LBG VQ methods above without Dual-Direction Prediction [2], the entropy generated by expansion LBG VQ method [1] sometimes will be larger than that generated by traditional LBG VQ method [3], and when using these LBG VQ methods above after Dual-Direction Prediction [2], CR (compression ratio) generated by expansion LBG VQ method [1] sometimes will be less than that generated by traditional LBG VQ method [3], while the entropy generated by the method proposed in this paper will be much less than that generated by either traditional LBG VQ method [3] or the expansion LBG VQ method [1], and CR generated by the method proposed in this paper will be much larger than that generated by either traditional LBG VQ method [3] or the expansion LBG VQ method [1]. 相似文献
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介绍了超导螺线管的冷铁轭优化设计方法, 即采用均匀设计结合有限元软件Opera作为试验手段进行研究。 对该方法进行了举例说明, 并得到物理量与参数之间的关系式, 并验证了关系式的精度, 以此证明此优化方法的可行性。 A method of studying the effect about cold yoke on the superconducting solenoid is introduced in this paper. In this method the uniform design table was used to arrange experiments. And then these experiments were executed by OPERA software package. Finally, the results were analyzed by the Stepwise Regression Analysis. An example according to the method is described and the reliability of this method is also proved. 相似文献
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《Journal of Physics and Chemistry of Solids》1959,10(4):314-320
An approximate method is derived for calculating the energy band of solids, analogous to the orthogonalized plane-wave method. In this method the exact condition for the orthogonality of the wave functions of valency electrons to the wave functions of the electrons of ions is replaced by a repulsive potential, determined statistically. It is shown by the example of the energy spectrum of diamond that despite the relative simplicity of this method, its results are comparable to those given by other methods. Correlation is also carried out between this method and the Phillips energy-band interpolation scheme. 相似文献
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The relationship between the object-plane phase and the intensity distribution in the Fresnel region can be described by the transport of intensity equation (TIE). The phase distribution can thus be uniquely determined by solving TIE. In this study, a full multigrid preconditioned conjugate gradient (FMG–CG) method is proposed to numerically solve the TIE for phase retrieval. The full multigrid method is a scalable algorithm, and can be parallelized readily and efficiently. By using this method as a preconditioner of the preconditioned conjugate gradient (PCG) method, fast convergence is obtained. The simulation experiments show that complicated phase distributions with fast convergence speed can be retrieved by this composite method. 相似文献
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This paper proposes a new Adomian decomposition method by using integrating factor. Nonlinear models are solved by this method to get more reliable and efficient numerical results. It can also solve ordinary differential equations where the traditional one fails. Besides, the complete error analysis for this method is presented. 相似文献
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Kuniyuki Motojima Shogo Kozaki 《International Journal of Infrared and Millimeter Waves》2002,23(1):157-166
A new near-to-far-field transformation that combines the FDTD and the series solution is presented. In this method, near-field data is calculated by FDTD and far-field data is also expressed by series solution. The boundary condition is applied to a virtual surface, which encloses arbitrarily shaped scatterers. In order to verify this method, scattering patterns from this transformation are compared with scattering patterns from exact solution. Numerical results show that errors in the far-field data from this method is less than surface equivalence theorem. Thus, this method is valid for obtaining the far-field data. 相似文献
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本文提出了一种利用补偿原理直接测量压电换能器串联谐振频率fs和并联谐振频率fP的新方法一补偿法。在这种方法测量原理的基础上,进行了实际测量,并设计了一种实用的测量电路。采用此方法测量的测量结果与电桥法的结果相符得很好。 相似文献