Radar imaging of a simple model of non-Gaussian one-dimensional random surface

Author(s):  
J.V. Toporkov ◽  
G.S. Brown
2016 ◽  
Author(s):  
E. R. Méndez ◽  
G. D. Jiménez ◽  
A. A. Maradudin

1. Introduction .—Gamow's elegant deduction by general arguments of the law of radioactive decay by α-particle emission and his subsequent investigations on artificial disintegration suggested to us the desirability of investigating as closely as possible any simple model of a decaying nucleus as a verification of his general approximations. For the model chosen the exact investigation of the decay process is almost trivial. Since we obtained this, now some time ago, Dr. Gamow informed us that he had also obtained equivalent detailed results. Still more recently such results have been published by Kudar. We shall not therefore dwell upon them here. The application of the same ideals, however, to the reverse process of penetration presents points of very definite interest, which we think are well worth discussion. The main point that arises is that the chance of penetration α-particle is or is not equal to a characteristic energy of the nucleus itself. This is a point which is not dealt with by Gamow in his paper. We have discussed it with him, and now put forward the results we have obtained. Since the solution of the decay problem is required in the main discussion of the penetration of α-particles into the nucleus it is included here in 2 for reference. We must emphasise that we claim no novelty, except of detail, for the work of 2; the general lines by now are a matter of fairly common knowledge.


Author(s):  
A. J. Allnutt

SynopsisThe Langevin equation for the harmonic oscillator is solved by a different method from that normally used. The approximate solution for the case of the slightly anharmonic oscillator is then obtained by an iterative procedure and the results are illustrated by a numerical example based on a simple model of a crystalline solid.


1956 ◽  
Vol 52 (4) ◽  
pp. 712-718 ◽  
Author(s):  
H. N. V. Temperley

ABSTRACTA very simple model, consisting of N particles moving in a one-dimensional assembly divided by potential ‘humps’ into M cells, is studied. The process of passing from a quantum-mechanical description of such an assembly to the equation of diffusion type that governs it in practice is shown to consist of at least three separate steps: ‘averaging over phases’, and letting N and M become large. The effects of these steps are considered separately. Strict irreversibility in time appears after the first step, but the assembly remains ergodic until after the second step and fluctuations persist until after the third step.


2000 ◽  
Vol 5 (3) ◽  
pp. 179-187 ◽  
Author(s):  
I. Katzorke ◽  
A. Pikovsky

We consider complex dynamical behavior in a simple model of production dynamics, based on the Wiendahl’s funnel approach. In the case of continuous order flow a model of three parallel funnels reduces to the one-dimensional Bernoulli-type map, and demonstrates strong chaotic properties. The optimization of production costs is possible with the OGY method of chaos control. The dynamics changes drastically in the case of discrete order flow. We discuss different dynamical behaviors, the complexity and the stability of this discrete system.


1979 ◽  
Vol 101 (4) ◽  
pp. 409-417 ◽  
Author(s):  
R. S. Sayles ◽  
T. R. Thomas

Surface and profile measurements and their resulting statistics, based on samples of up to half a million heights, are compared and their interrelationship examined for several common engineering surfaces. The measurements are employed to check the applicability of the spectral moment approach to random surface specification. This technique relates many important geometrical properties of a surface to those of its constituent profiles. A relationship is found to exist between the sampling interval and the spatial size of features accommodated by this form of approach. This explains, for example, why 4 and 8 nearest neighbor summit-density analyses based on the same square grid sampling interval reveal very different results. Having established this basic relationship, good agreement is found between theory and measurement over a large range of sampling intervals. In particular, summit densities and distributions are shown to agree well with theory even for non-Gaussian height distributions. It is shown how the isotropic analysis can be extended to cover directionally anisotropic structures such as ground surfaces by defining equivalent movements based on two profiles at right angles. Here again measurements are in good agreement with theory.


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