Clear Physical Sense Research Articles

Energy behavior of hadronic spectra in the dual parton model

The energy behavior of the hadronic spectra is studied in the framework of the dual parton model. The problem of Feynman scaling violation in the central and fragmentation regions is discussed. For the fragmentation region a simple analytical expression is derived which has a clear physical sense and coincides in the form with corresponding formulas of quark cascade models. The corrections to this expression, taking into account a slight violation of scaling in the fragmentation region, are obtained.

Stellar surface oscillations under the action of hydrodynamical perturbations

Abstract The problem of stellar surface oscillations under the action of perturbations in the inner layers of the star is considered. A one-dimensional hydrodynamical model is adopted to describe relatively short (compared with the stellar radius) perturbations of gas in a non-stationary gravity field. The Legendre transformation technique is used to obtain exact solutions describing the star's surface oscillations. It is shown that if the perturbations in the inner layers of the star have small energy, then the extreme characteristics of the star surface oscillations (displacement and velocity) do not depend on the nonlinearity of the problem, and thus, they can be calculated in the frame-work of a linear hydrodynamical model. The criterion for breaking of the wave coming to the star's surface is obtained. It is found that this criterion can be defined by solving the linear problem and therefore having a very clear physical sense (the ratio of the wave acceleration to the acceleration due to gravity). It...

Group Theoretical Setting of Manipulators Kinematics and Control

This paper sets some questions on kinematic and dynamic modelling and control of manipulators through vector parametrization of the special orthogonal group SO(3), which presense can not be avoided in the description of the rotation motions. All vectors belonging to the real three dimensional space R3 with definite composition law form a group, isomorphic to a part of SO(3). Remaining part is covered by another chart with the same codomain. Any vector from this group which we shall call vector-parameter has a clear physical sense: it coincides with the rotational axis and its module is equal to the tangent of the half rotational angle. In this aspect all analytic presentations of the direct and inverse kinematic problems of the manipulators systems as of the dynamic equations of motion contains the theory of algebraic or differential equations respectively over a group. The aim of the paper is to show that in the suggested approach, be cause of the simple composition law, the number of the multiplications in the position problem of manipulator systems is reduced with about AO p.c. This makes it more appropriate and convinient for complex spatial anthropomorphic structure description and for on-line manipulator control.

Acoustic diffraction analysis by the impulse response method: A line impulse response approach

Acoustic diffraction of plane impulsive waves is considered for free‐field, baffled, and pressure release boundary conditions, in the case of an arbitrary spatial distribution of combined, amplitude‐time delay modulation in an aperture. The method is based on the impulse response analysis of parallel aperture lines, the line impulse responses being then integrated to give an aperture impulse response. A closed‐form, analytical expression is derived for lines having an arbitrary amplitude modulation. In the case of nonmodulated apertures of an arbitrary shape, the aperture impulse response is also of an analytical form, directly involving the aperture contour line. The analysis is performed with emphasis on maintaining clear physical sense of successive evaluation steps.