Phase considerations in digital image analysis of polarized-light images

The phase statistics in digital imaging (DIA) is considered for the case when Fourier transformation is performed over images obtained in polarized light. An additional phase shift associated with “directionality” of scatterers is shown significant for the true simulation of nonisotropic scattering. The proof is based on analysis is particular of DIA simulated patterns and optical Fourier transforms of spherulitic particles, the latter transforms being obtained by optical modelling of spherulitic polarized light scattering. The constraints on the phase shift in the simulation process have been established. The phase analysis additionally implies that the nonisotropic scattering might be considered as a new special case of the apodization technique, with a number of potential applications. © 1994 John Wiley & Sons, Inc.     

A further study of the anomalous response of an elastic-plastic structural model to impulsive loading

The dynamic response to impulsive loading of a new elastic-plastic structural model, i.e. the double-tier-spring (DTS) model, is further studied to explore the dependence of the deformation history of the springs in the model on the structural and loading parameters, so as to deepen the understanding of the intrinsic mechanism of the anomalous behavior for a certain range of parameters' combination.     

Slow Modes in Passive Advection

The anomalous scaling in the Kraichnan model of advection of the passive scalar by a random velocity field with nonsmooth spatial behavior is traced to the presence of slow resonance-type collective modes of the stochastic evolution of fluid trajectories. We show that the slow modes are organized into infinite multiplets of descendants of the primary conserved modes. Their presence is linked to the nondeterministic behavior of the Lagrangian trajectories at high Reynolds numbers caused by the sensitive dependence on initial conditions within the viscous range where the velocity fields are more regular. Revisiting the Kraichnan model with smooth velocities, we describe the explicit solution for the stationary state of the scalar. The properties of the probability distribution function of the smeared scalar in this state are related to a quantum mechanical problem involving the Calogero–Sutherland Hamiltonian with a potential.Partially supported by NSF Grant DMS-9205296     

Anomalous behaviour of sound velocity in the highT c superconductor YBa2Cu3O7

The longitudinal acoustic wave velocity in YBa₂Cu₃O₇ has been measured in the range 300 to 85 K using the ultrasonic pulse superposition technique. The sound velocity shows a steep drop in its value at 260 K and decreases continuously till the superconducting transition temperature. BelowT _c the sound velocity increases steeply. A hysteresis is seen when the experiments are performed during a cooling-warming cycle. The results are compared with recent measurements by Ewertet al on the samples with the same chemical composition.     

Correlation of reactivity with structural factors in a series of Fe(II) substituted cobalt ferrites

A series of powdered cobalt ferrites, Co_xFe_3−xO₄ with 0.66?x<1.00 containing different amounts of Fe^II, were synthesized by a mild procedure, and their Fe and Co site occupancies and structural characteristics were explored using X-ray anomalous scattering and the Rietveld refinement method. The dissolution kinetics, measured in 0.1 M oxalic acid aqueous solution at 70 °C, indicate in all cases the operation of a contracting volume rate law. The specific rates increased with the Fe^II content following approximately a second-order polynomial expression. This result suggests that the transfer of Fe^III controls the dissolution rate, and that the leaching of a first layer of ions Co^II and Fe^II leaves exposed a surface enriched in slower dissolving octahedral Fe^III ions. Within this model, inner vicinal lattice Fe^II accelerates the rate of Fe^III transfer via internal electron hopping. A chain mechanism, involving successive electron transfers, fits the data very well.     

X-ray emission from aluminium under intense, ultrashort irradiation

We present studies of X-ray emission from aluminium under picosecond and femtosecond irradiation in the intensity range 10¹²-10¹⁵ W cm^-2. We use a new and simple method to measure spectrally resolved absolute X-ray yields. It is shown that the X-ray yields can be obtained for arbitrary levels of X-ray flux. We present details of the variation of the absolute yields as a function of wavelength, intensity, polarization and pulse duration of the incident laser radiation. Electron temperatures in the keV range are observed at 10¹⁵ W cm^-2 with femtosecond laser pulses. Received 12 August 1999 and Received in final form 29 November 1999     

Intermittent type fluctuation of target fragments produced in 16O-AgBr interactions at 4.5 AGeV/c

A study of intermittency of target associated fragments produced in the interactions of 16OAgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments,Fq,has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variable X(z) suggested by Bialas and Gazdzicki.The anomalous dimensions,dq,increase linearly with the order of moments,q.This observation indicates the association of multifractility with production mechanism of target associated fragments.     

Correlation functions in the anomalous-dimension approximation for a multicomponent liquid

We analyze the features of solutions for pair correlation functions in the case of a multicomponent liquid. We obtain these solutions based on the Ornstein-Zernike equation. In the anomalous-dimension approximation, we find expressions for pair correlation functions in the case of a spatially unbounded multicomponent liquid. We show that all pair correlation functions for a system in the close vicinity of the critical state are described by a general expression similar to the expression for a pair correlation function in the case of a one-component liquid. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 153, No. 1, pp. 124–129, October, 2007.     

Thickness dependence of the anomalous Hall effect in disordered face-centered cubic FePt alloy films

The anomalous Hall effect in disordered face-centered cubic(fcc) FePt alloy films is experimentally studied. The longitudinal resistivity independent term of the anomalous Hall conductivity(AHC) increases and approaches saturation with increasing film thickness. The contribution of side jump scattering is suggested to decrease monotonically with increasing film thickness, which can be ascribed to the variation of the surface scattering with the film thickness. The sign of the skew scattering contribution to the AHC is opposite to that of the intrinsic contribution in the system.     

在冲击载荷作用下弹塑性圆板的反直观动力行为数值分析

对周边简支理想弹塑性圆板受脉冲载荷作用时的动力行为进行了数值计算与分析,揭示了板类结构反直观动力行为的客观存在性．通过分析发现,随着脉冲强度的增加,存在几个窄的载荷区域,板的响应是反直观的,而且在此附近,结构参数、载荷等因素的微小改变将导致响应模式的很大差异,表明反直观行为对这些参数的极其敏感性．进一步计算表明,这一特殊的动力行为主要与板内力间的相互耦合作用密切相关,同时,卸载后的结构反弹到另一侧时发生较大的反向塑性变形,导致能量的进一步耗散,使板呈现反常的动力响应．这一现象是几何与材料两种非线性相互作用的结果。