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Improvement of Low-Frequency Acoustic Spatial Correlation by Frequency-Shift Compensation 总被引:7,自引:0,他引:7
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Interference of normal modes can lead to longitudinal decorrelation of an ocean acoustical field, so It can aecrease the gain of a wide-aperture array. Based on waveguide invariance, we propose a frequency-shift compensation method that can be used to improve the signal correlation received at different locations with certain longitudinal separations. The method is verified by experimental data. 相似文献
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Based on the technique of integration within an ordered product of operators we investigate a completeness relation of pure states (such as the coordinate eigenstate, the momentum eigenstate and the coherent state) into normally ordered Gaussian forms. The Weyl ordering invariance under similarity transformations is employed to reveal physical meaning of a kind of normally ordered Gaussian operators, which have the similar forms to the bivariate normal distributions in statistics, i.e., the thermo mixed state density matrix. 相似文献
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液晶显示器颜色特征化的分段分空间模型 总被引:2,自引:0,他引:2
为了提高液晶显示器(LCD)颜色特征化精度,根据液晶显示器色品恒定性和通道独立性较差的特点,提出了分段分空间模型。该模型首先用分段二次多项式拟合单通道驱动值和三刺激值的关系,然后再根据不同RGB子空间的颜色特性加上适当的干扰项对液晶显示器进行颜色特征化。实验结果表明,在训练样本和检验样本数分别为91和512时分段分空间模型的CIELAB平均色差为1.5881,最大色差为6.0249;通过与三维查找表、Mask、S-Curve及TPC模型的比较研究,验证了当训练样本数不多时分段分空间模型的颜色预测精度最高。 相似文献
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This paper focuses on studying non-Noether conserved quantities of Lie
symmetry and of form invariance for a mechanical system in phase space
under the general infinitesimal transformation of groups. We obtain a new
non-Noether conserved quantity of Lie symmetry of the system, and Hojman and
Mei's results are of special cases of our conclusion. We find a
condition under which the form invariance of the system will lead to a Lie
symmetry, and, further, obtain a new non-Noether conserved quantity of form
invariance of the system. An example is given finally to illustrate these
results. 相似文献
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Lorentz Invariance and Brownian Motion of Test Particles with Constant Classical Velocity in Electromagnetic Vacuum
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We show that the velocity and position dispersions of a test particle with a nonzero constant classical velocity undergoing Brownian motion caused by electromagnetic vacuum fluctuations in a space with plane boundaries can be obgained from those of the static case by Lorentz transformation. We explicitly derive the Lorentz transformations relating the dispersions of the two cases and then apply them to the case of the Brownian motion of a test particle with a constant classical velocity parallel to the boundary between two conducting planes. Our results show that the influence of a nonzero initial velocity is negligible for nonrelativistic test particles. 相似文献
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New Types of the Lie Symmetries and Conserved Quantities for a Relativistic Hamiltonian System 总被引:2,自引:0,他引:2
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LUOShao-Kai 《中国物理快报》2003,20(5):597-599
For a relativistic Hamiltonian system,two new types of the Lie symmetries and conservation laws are given under infinitesimal transformaitons of groups.On the basis of the theory of invariance of the relativistic Hamiltonian equations under infinitesimal transformations and introducing infinitesimal transformations for time t,generalized coordinates qs and generalized monenta ps,we obtain the determinging equations,the structure equations and the conserved quantities of the Lie symmetries.Introducing infinitesimal transformation for generalized coordinates qs and generalized momenta ps,we construct the Lie symmetrical transformations of the system,which only depend on the canonical variables.A set of conserved quantities are directly obtained from the Lie symmetries of the syste.An example is given to illustrante the application of the results. 相似文献
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LED大屏幕空间显色恒定性 总被引:1,自引:0,他引:1
通过两组三基色LED(发光二极管 )样品色度和光强空间分布的测量 ,计算了由这两组LED制作的大屏幕再现的D6 5白平衡点、我国青年女性面部肤色、红旗丝织绸、蓝布和绿滤色片等五种色样在CIELUV均匀颜色空间的色度随观察角 ( 0°~ 70°)的变化及其与正向 ( 0°)再现色之间的色差。结果表明 ,LED单管光强随观察角的变化幅度和三基色管光强空间分布特性的一致性是影响大屏幕空间显色恒定性的主要因素。在确定大屏幕空间显色恒定性允差后 ,可用文中提供的方法对制作大屏幕的LED进行筛选。 相似文献
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