Mutual transformations between the P–Q,Q–P,and generalized Weyl ordering of operators

Based on the generalized Weyl quantization scheme, which relies on the generalized Wigner operator Ok （p, q） with a real k parameter and can unify the P-Q, Q-P, and Weyl ordering of operators in k = 1, - 1,0, respectively, we find the mutual transformations between 6 （p - P） （q - Q）, （q - Q） 3 （p - P）, and （p, q）, which are, respectively, the integration kernels of the P-Q, Q-P, and generalized Weyl quantization schemes. The mutual transformations provide us with a new approach to deriving the Wigner function of quantum states. The - and - ordered forms of （p, q） are also derived, which helps us to put the operators into their - and - ordering, respectively.     

Statistic of a Gaussian beam from an arbitrary rough target in the single passage atmospheric turbulence

The extended Huygens-Fresnel principle and Goodman model was utilized for target surface to derive the mutual coherence function (MCF) of a Gaussian beam reflected from an arbitrary rough target in atmospheric turbulence. According to the MCF, expressions of the mean irradiance and average speckle size at the receiver were obtained. The analysis indicated that the mean intensity is closely related to the ratio of root mean square (rms) height to the lateral correlation length. In addition, the speckle size at the receiver is associated with turbulence strength, propagation distance and roughness of the target. The results can be reduced to the result of a Gaussian beam illuminating rough target and scattering from a target in free space.     

生产税对居民初次分配总收入影响研究

基于国民经济核算的一般原理及核算账户之间的平衡关系,构建生产税影响居民初次分配总收入的路径图,并运用比例分析法和投入产出法对资金流量表及投入产出表进行建模,从生产税的角度研究居民初次分配总收入占比下降的原因。结果表明,2000年以来企业部门缴纳的生产税占比的上升挤占企业部门支付的劳动者报酬份额,是导致居民部门初次分配总收入占比下降的重要原因。     

Mutual funds performance appraisal using stochastic multicriteria acceptability analysis

Mutual fund investors are concerned with the selection of the best fund in terms of performance among the set of alternative funds. This paper proposes an innovative mutual funds performance evaluation measure in the context of multicriteria decision making. We implement a multicriteria methodology using stochastic multicriteria acceptability analysis, on Greek domestic equity funds for the period 2000-2009. Combining a unique dataset of risk-adjusted returns such as Carhart’s alpha with funds’ cost variables, we obtain a multicriteria performance evaluation and ranking of the mutual funds, by means of an additive value function model. The main conclusion is that among employed variables, the sophisticated Carhart’s alpha plays the most important role in determining fund rankings. On the other hand, funds’ rankings are affected only marginally by operational attributes. We believe that our results could have serious implications either in terms of a fund rating system or for constructing optimal combinations of portfolios.     

Interplay between phase formation mechanisms and magnetism in the Sr2FeMoO6–δ metal‐oxide compound

Double perovskites with the structural formula A₂BB′O_6±δ, especially the strontium ferromolybdate Sr₂FeMoO_6–δ, have attracted a lot of attention due to their unique magnetic and electrical properties and a possible application in spintronic devices. However, a strict correlation between the functional characteristics of Sr₂FeMoO_6–δ and its synthesis technology has been lacking up to date. Thus, we have studied in the present work the crystallization kinetics of Sr₂FeMoO_6–δ using reagents with different pre‐history as well as the structural and magnetic properties of the obtained compounds. Differences in the crystallization kinetics as well as higher magnetic inhomogeneity of Sr₂FeMoO_6–δ synthesised from a mixture of MoO₃, Fe₂O₃, SrCO₃ in comparison with the compound synthesised from the SrFeO_2.5 and SrMoO_4–y precursors have been found and interpreted. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Characterization of radix rehmanniae processing procedure using FT-IR spectroscopy through nonnegative independent component analysis

A method is proposed for monitoring the radix rehmanniae proparate processing procedure and determining the endpoint of the process using attenuated total reflectance (ATR) FT-IR through nonnegative independent component analysis (ICA). In the proposed method, ATR FT-IR spectra of the samples were firstly measured at different steaming periods. Then, nonnegative ICA was used for direct estimation of the feature spectra of the pure components in the mixture without pre-separation and other prior information. The estimated independent components (ICs) and their variation of the relative concentrations were used to characterize the processing procedure and determine the endpoint. The results show that the estimated three ICs are consistent with that of the chemical components in the mixtures, i.e. catalpol/rehmaionoside, glucose, and other compounds that nearly keep invariant during the processing procedure. The endpoint determined by the IR-ICA method is 15 h, which was located in the range obtained by expert sensory analysis, whereas the endpoint determined by the traditional sensory analysis is 14 ∼ 17 h and even 14 ∼ 20 h, which showed the significant deviation of the endpoints determined by different operators. Figure Characterisation of radix rehmanniae processing procedure using FT-IR spectroscopy through nonnegative independent component analysis     

耦合摆特性模拟及振动耦合现象演示

分析了机械耦合摆的振动特性及耦合过程,提出了利用互感耦合电路模拟耦合摆的方法;设计并制作了—种互感耦合装置,模拟机械耦合摆的振动耦合和能量转换过程;通过与机械耦合的比对演示,将两种耦合的特性分析归结为相同的数学问题,在演示物理现象的同时,培养学生数学建模能力和对系统的综合分析能力.     

互耦相对论返波管等同锁相和功率放大的粒子模拟

推导了两个互耦高功率微波振荡系统等同锁相后的锁定频率公式,并利用粒子模拟软件对两个互耦相对论返波管进行了数值仿真实验。模拟时将相同结构的两个相对论返波管并排放置在一起,在它们的慢波结构的第１个波谷处,用一条饼状狭缝将它们并联起来,分别输入不同的加速电压,让它们工作于不同的状态。粒子模拟的结果表明:这两个并联的互耦相对论返波管之间进行了等同锁相,它们的频率都被锁定在同一个特定的频率点上,且其注波能量转换效率都提高了,总输出功率比单独工作时的总功率增加了约10%,同时耦合之后功率输出更平稳。     

独立成分分析及其在图像处理中的应用

独立成分分析是一种新的信号处理技术,在数字图像处理的诸多方向均表现出其独特性。对独立成分分析(ICA,Independent Component Analysis)及其在图像处理中的应用进行了综述。简要介绍了独立成分分析的数学模型,给出了极大化非高斯性的ICA估计方法、极大似然ICA估计方法、极小化互信息ICA估计方法的目标函数及其优化算法;对ICA在像素级图像融合、运动目标检测、人脸检测及特征提取、大脑信号和图像分析、数字水印、有噪图像分离等方向的应用研究进行了评述,进而显示ICA的应用价值和发展空间。     

拮抗作用及传统医学的食物相克

微量元素的生理活性取决于其化合物的溶解性,配位状态、浓度、溶液酸度以及其它元素浓度,拮抗作用的本质是元素的结构－性质－活性关系。其机理主要包括直接反应、形成ＭＴ的抑制反应,相似元素竞争配位部位以及社会、心理、遗传和个体易感性等,传统医学煌食物相克的实质还是物质的拮抗作用。