共查询到20条相似文献,搜索用时 562 毫秒
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由完全开放系统的统计分布(也称N-E-V分布)计算了几个热力学系统的热力学量,其结果是与其他分布相同的,只是由平均值代替了固定不变值,但计算的相对涨落却是与通常理论完全不同的.通常的分布计算的相对涨落虽然不完全相同,但都正比于1/N,而由完全开放系统的统计分布计算的相对涨落却正比于1. 相似文献
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研究了单模激光中产生的二次谐波的统计性质,用全饱和激光理论导出了二次谐波光子计数m的几率分布函数、二次阶乘矩和三次阶矩的表达式,同实验值比较,理论与实验在阈值附近符合得很好。研究结果表明,激光场基波和二次谐波的涨落随空腔衰减常数的增大而减小;当激光场中含有乘性噪声时,乘性噪声增强基波的涨落,同时抑制二次谐波的涨落。 相似文献
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本文系统地研究了第核子从3.7到200GeV的束流能区氧核诱发作用中的单粒子赝快度分布和二粒子关联极限碎裂行为.利用阶乘矩与多粒子的赝快度分布的关系、考察了多粒子分布动力学涨落的极限碎裂行为. 相似文献
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利用单事例阶乘矩方法计算了NA27数据的事例空间矩Cp,q(M).与纯统计涨落的蒙特卡罗事例样本的计算结果比较,表明Cp,q(M)随M的变化主要由统计涨落引起的.对NA27数据的赝快度间隔作不稳定性分析,计算了类熵量Sq和Σq,两者都显著地偏离于1.Sq和Σq随q的变化呈指数关系.FRITIOF模拟能重现此标度行为,但数值偏离较大. 相似文献
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This paper verifies the feasibility of the relative entropy method in selecting the most suitable statistical distribution for the experimental data, which do not follow an exponential distribution. The efficiency of the relative entropy method is tested through the fractional order moment and the logarithmic moment in terms of the experimental data of carbon fiber/epoxy composites with different stress amplitudes. For better usage of the relative entropy method, the efficient range of its application is also studied. The application results show that the relative entropy method is not very fit for choosing the proper distribution for non-exponential random data when the heavy tail trait of the experimental data is emphasized. It is not consistent with the Kolmogorov–Smirnov test but is consistent with the residual sum of squares in the least squares method whenever it is calculated by the fractional moment or the logarithmic moment. Under different stress amplitudes, the relative entropy method has different performances. 相似文献
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A new imaging system based on optical frequency domain reflectometry is presented. The intensity-integration effect of the
charge coupled device camera to be used acts effectively as a low pass filter for the intensity fluctuation and the 2nd order
moment of the detected signals is proportional to a low beat frequency component of the interference signal. Consequently,
two-dimensionally imaging of the reflectance of a selective plane located in scattering media is demonstrated. 相似文献
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By extending the constitutive theories for homogeneous granular flows of highly inelastic spheres by Richman (J. Rheol 33 (1989) 1293), Chou (J. CSME 16-6 (1995) 577), and Chou and Richman (Physica A 259 (1998) 430), the collisional source of the second moment of fluctuation velocity and pressure tensor were developed in this study for inhomogeneous rapid granular flows of identical smooth highly inelastic spheres. The important mean fields in this flow are the solid fraction, mean velocity, and full second moment of fluctuation velocity. The collisional source of second moment and the collisional flux of momentum are based upon an anisotropic Maxwellian velocity distribution function. The constitutive theory was combined with the experimental results measured by Hsiau and Jang (Exp. Thermal Fluid Sci. 17 (1998) 202) so as to determine the profiles of pressure tensor and collision source of second moment in the inhomogeneous rapid granular shear flows of inelastic spheres. The normal pressure discrepancies were also observed. 相似文献
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用视密度加权平均二阶矩模型模拟旋流两相流动 总被引:1,自引:0,他引:1
本文用视密度加权平均代替时平均,建立了视密度加权平均的统一二阶矩两相湍流模型方程组(MUSM),其中用体积分数代替了数密度,用颗粒驰豫时间作为封闭两相脉动速度关联方程耗散项的时间尺度,并引入了颗粒视在的气体速度脉动的输运方程。用MUSM模型模拟了旋流数为0.47的气粒两相流动。并和实验结果及时间平均的USM模型的模拟结果进行了对照,两种模型均能较好地预报的两相的轴向和切向速度,轴向和切向脉动速度。此外,MUSM模型可以减少所用方程数,节省计算量。因此视密度加权平均的统一二阶矩两相湍流模型是一种对时间平均的统一二阶矩模型的改进,今后可以进一步扩大应用。 相似文献
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In this paper, for a multi-variate random process of arbitrary distribution type which can be considered to be a sum of two different random processes as a result of the natural internal mechanism of the fluctuation, or of an artificial analytical classification of the fluctuation, a unified statistical treatment for the multi-variate joint probability distribution and the multi-variate joint moment with arbitrary order of the resultant random process is introduced exactly in the form of finite expansion terms. The validity of the present theory has been experimentally confirmed not only by means of digital simulation but also by Hiroshima City street noise data. The experimental results clearly show the usefulness of the theory, and also the importance of the exact correction to the truncation error of the expansion expression. 相似文献
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机载多环架光电吊舱伺服控制电机的力矩估算 总被引:1,自引:0,他引:1
采用多环架稳定的机栽光电吊舱,需要科学准确地估算各环架伺服控制电机的力矩,选择满足控制精度和安装要求的控制电机。通过分析各种扰动作用的途径和多环架结构的抑制效果,估算系统实现指标所需要的加速度、速度,综合出各环架控制电机应有的力矩。得到的数据可用于吊舱系统的性能实现和小型化设计。 相似文献