Acta Physica Polonica A
Vol. 93 Supplement '98
 
ROTATION OF DOMAIN STATES IN FERROELASTIC DOMAIN STRUCTURES

L. Inovecky

Gymnazium, Zborovska 45, Praha 5, 15000, Czech Republic

This work deals with misfit angles, which are observable in ferroelastic phase transitions. In the literature the misfit angles were calculated for six different ferroelastic phase transitions, where there is only one possible misfit angle. In this work the method for obtaining all misfit angles (for the cases where there is more than one possible) is introduced. Also the expressions for all possible misfit angles for each ferroelastic species are given.
PACS numbers: 62.20.Dc
 
CCD OBSERVATIONS OF THE MINOR PLANET (73) KLYTIA

G. Szabo

``Radnoti Miklos'' Experimental High School, Szeged, Hungary

We present unfiltered CCD observations of the minor planet (73) Klytia carried out between 20th February and 2nd March 1997. These measurements allowed us to perform a detailed study regarding the asteroid's light variation. The period of the light curve, found in the 21 hours long data series obtained on 4 nights is 8.275 hours (0.3448\pm0.0003 day). The amplitude of the light variation is 0.28 mag. Assuming that the light variation is due to the rotation of the non-spherical minor planets, we have fitted a rotating ellipsoid to the observed light curve and derived its minimal a/b axis ratio equal to 1.28. The fitting method was quite approximate, therefore its results should be considered as rough estimates of the real shape.
PACS numbers: 96.30.Ys, 95.75.De, 95.75.Mn
 
INFLUENCE OF LIGHT ON DISSOLUTION PROCESSES IN CHALCOGENIDE GLASSY SEMICONDUCTORS

D. Boyarskiy

Mivza Ovda 110/28, Beer Sheva, Israel

In this work characteristics of dissolution processes in chalcogenide glassy semiconductors (illuminated and non-illuminated) were studied. The main purpose of this work was studying different compounds of the chalcogenide glassy semiconductors of the As-Se and As-S systems and their reciprocation with some selective solvents. The author of this document and his instructor consider as the most significant result of this work the discovery of an effective positive solvent (\gamma\approx100) in As_45S_55 films.
PACS numbers: 71.55.Jv, 78.90.+t
 
SEA-BOTTOM PROFILE - REMOTE DETERMINATION PROBLEM IN GEOMETRICAL APPROACH

O. Kuzminov

Second General Education Technical Lyceum attached to Samara State Technical University Rabochaya 19, 443041 Samara, Russia

The problem of the remote determination of a sea bottom is discussed. The approach which enables analysis of the experimental data obtained after reflection of audio signal from a sea bottom is presented. A computational algorithm for solving this problem was written. The examples of results for the sea-bottom profile interpolation that has been done with help of ``Maple-V, Release 3 for Windows'' are presented.
PACS numbers: 91.50.Ey, 87.59.Fm
 
SOME GENERALISATIONS OF BRACHISTOCHRONE PROBLEM

A.S. Parnovsky

Lyceum No.~145 for Natural Sciences, Sh. Rustaveli 46, Kiev-23, 252023, Ukraine

300 years ago Johann Bernoulli solved the problem of brachistochrone (the problem of finding the fastest travel curve's form) using the optical Fermat concept. In the same way we solved some generalisations of this problem. We obtained the fastest travel curve's form in a gravitational field for a point-like mass. When moving in a uniform gravitational field we considered the influence of the dry friction or drag.
PACS numbers: 03.20.+i, 46.10.+z
 
LONG-RANGE FERROMAGNETIC ORDER IN ENSEMBLE OF NANOMETRIC MAGNETIC PARTICLES WITH GIANT MAGNETIC MOMENTS

N.G. Takzei

Lyceum No. 145 for Natural Sciences, Sh. Rustaveli 46, Kiev-23, 252023, Ukraine

Using X-ray and magnetic methods as well as small-angle neutron scattering, it is shown as an example of the decomposing alloy Cu_64Mn_9Al_27 that the appearance of long-range ferromagnetic order in a system of small superparamagnetic particles dissolved in nonmagnetic metallic matrix is due to cooperative ordering of their magnetic moments.
PACS numbers: 61.46.+w, 75.25.+z, 75.20.En
 
DETERMINATION OF STRENGTH OF SOLID POROUS BODY

A.A. Vihtuk

Kiev Physics and Technique Faculty of the Kiev Polytechnic Institute, pr. Peremogi 37, Kiev, Ukraine

The problem of destruction of solid bodies is investigated by the science of strength of materials and constructions - mechanics of destruction, expounded on the base of modern conceptions about destruction of different nature bodies. Two kinds of material obtained in different ways have been investigated in this work. A method of alloying the micropowder composition by ultradispersed admixture was used. It increased a value of the Veibull parameter and of average strength of these materials. All these results were calculated and presented in diagrams.
PACS numbers: 07.10.Pz, 62.20.Mk, 81.05.Rm
 
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