ИЗЛУЧЕНИЕ ЧЕРЕНКОВА ПРОСТРАНСТВЕННОГО З АРЯДА В ВОЛНОВОДАХ И В НЕОГР АНИЧЕННОЙ СРЕДЕ

, - e . -. , .     

Colour centre in BaTiO3 single crystals

The position of the absorption band of a colour centre formed by one electron trapped on an oxygen vacancy, in a cubic modification of BaTiO₃ single crystals, is quantum mechanically calculated.

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BaTiO₃

- , , , BaTiO₃.

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In conclusion the author thanks Dr. M. Trlifaj, corresponding member of the Czechoslovak Academy of Sciences, for valuable suggestions and remarks. He also thanks Dr. H. Arend, B. Bezina, C. Sc., P. Coufová and V. Janovec, C. Sc., of the Institute of Physics, Czechoslovak Academy of Sciences, for helpful discussions.     

A model of Piron's preparation-question structures in Ludwig's selection structures

We give a model of the basic Jauch-Piron (JP) approach to quantum physics, i.e., of preparation-question structure (with four basic axioms and without axioms C, P, A), in terms of Ludwig's selection structure; in the latter structure the primitive notion of individual sample of a physical entity is formally described (without making reference to any probability concept). Once we interpret Piron's concept of question in Ludwig's context of a selection structure, we find that there is no difficulty in formalizing notions such as performable together questions; moreover, results such as = or ()= can be formally proved. We develop the theory along the lines of the JP approach; the set of JP propositions is derived and it turns out to be a complete lattice, as happens in Piron's theory, but with a different physical interpretation of the lattice operations. Finally, we study some connections between the standard Ludwig foundation and our approach.     

Определение дефекто в решетки третъего ро да и величины когерентн ых областей решетки у порошкооБразного в олъфрама

, . , , -, , , .     

ССЛЕДОВАНИЕ РАСПАДА Dy155 → Tb155

The gamma-spectrum and coincidences of gamma-rays appearing in Dy¹⁵⁵ Tb¹⁵⁵ decay have been measured with the aid of a scintillation gamma-spectrometer. The Dy¹⁵⁵ source has been obtained by a repeated chromatographic separation from Ho fraction produced by a spallations reaction Ta+p(E _p=660 MeV). Dy¹⁵⁵ appears as a decay product of Ho¹⁵⁵ (T _1/2= =45 min). In the gamma-spectrum new transitions in the energy range of 1170–2000 keV have been observed. As a result of- coincidence measurements we get a new energy level (1820±15 keV) of Tb¹⁵⁵.

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, Dy¹⁵⁵ . . .     

Extremal invariant states with a spectrum condition and Borchers' theorem

If the energy spectrum of an extremal invariant state is not the whole real line, it is shown that is either pure or uniquely decomposed into mutually disjoint pure states in the way that =^-1 F _{0 t} dt where is a pure state satisfying = with >0. Next we give a slightly generalized version of Borchers' theorem [1] on the innerness of some automorphism group of a von Neumann algebra with a spectrum condition.     

Nordström,Ehrenfest, and the Role of Dimensionality in Physics

In the summer of 1916, Finnish physicist Gunnar Nordström (1881–1923) arrived in Leiden to carry out research with Paul Ehrenfest (1880–1933), Hendrik A. Lorentzs successor in the chair of theoretical physics. Nordström had recently published the first five-dimensional unified model of the universe, a theory that went virtually unnoticed by the physics community. Ehrenfests personal journals reveal that Nordströms visit coincided with a flowering of Ehrenfests own interest in dimensionality, which resulted in his well-known paper on the connection between the fundamental laws of physics and the three-dimensionality of space. I examine Nordströms and Ehrenfests collaboration and explore the relationship between their ideas and the Kaluza-Klein model of five-dimensional unification.Paul Halpern is Professor of Physics at the University of the Sciences in Philadelphia. He received a Guggenheim Fellowship in 2002 to study the history of dimensionality in science.     

Fractal drums and then-dimensional modified Weyl-Berry conjecture

In this paper, we study the spectrum of the Dirichlet Laplacian in a bounded (or, more generally, of finite volume) open set R ⁿ (n1) with fractal boundary of interior Minkowski dimension (n–1,n]. By means of the technique of tessellation of domains, we give the exact second term of the asymptotic expansion of the counting functionN() (i.e. the number of positive eigenvalues less than ) as +, which is of the form ^/2 times a negative, bounded and left-continuous function of . This explains the reason why the modified Weyl-Berry conjecture does not hold generally forn2. In addition, we also obtain explicit upper and lower bounds on the second term ofN().     

Influence of the Flux Density,the Flux,and the Energy of Electrons on the Change in the Optical Properties of ZnO + K2SiO3 Coatings

The change in the diffusion reflection spectra and the total solar radiation absorption coefficient as by a reflecting heat-regulating coating (HRC) fabricated from ZnO pigment and K₂SiO₃ liquid potash glass in the People's Republic of China is investigated as a function of the flux density , the flux , and the energy E of electrons. The established regularities in the changes of a _s and under irradiation provide additional information on the formation of color centers (CC) in these systems and correlate with the results obtained previously for coatings fabricated in Russia.     

Nonlocal structures: Bilocal photon

As a starting point, it is postulated that all particles and fields are built from a single primitive field, which must then be a massless fermion with a spin of one-half. Two helicities are embodied in a spin of one-half. The vacuum is an open Fermi sea whose height is a wave number . Elementary particles are structures having the form of standing-wave systems floating on the vacuum sea, with the height providing both the scale of inner structural size and the mass unit for the elementary particle mass spectrum. A bilocal photon starts with a function describing two primitive quanta with parallel spin and opposite spin. A centroid-time wave equation then couples-in an infinite set of orthogonal functions. The introduction of an operatorQ permits the reduction of the infinite secular determinant to a finite six-by-six determinant. Solutions (for the infinite expansion) are obtained describing photons with right-handed and left-handed polarizations. Superpositions of these give linearly polarized photons. Electric and magnetic field vectors, satisfying the vacuum Maxwell equations, are obtained from a bilocal Hertz vector given by = (2/³ c)(/t _r)_r(1,2), where (1,2) is the bilocal wave function, and t_r and r are the relative time and relative position variables.     

УпРУгОЕ РАссЕьНИЕ НУклОНОВ НА МИшЕНИ сО спИНОМ 1

1. , .

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Elastic scattering of nucleons on a target with spin 1

A method, by means of which it is possible to reconstruct a potential on the basis of data on elastic scattering, is investigated for the case of scattering of nucleons on targets with spin 1. Formulas are given which express the relations between a phenomenological potential and the elements of the scattering matrix.

     

The kinetics of phase transition in systems with nonconservative order parameter

The kinetics of ordering in systems described by the nonconservative order parameter is studied near the second-order transition critical point.On leave fromDepartment of Nuclear Physics and Biophysics, Faculty of Natural Sciences, University of P. J. afárik, Moyzesova 11, 041 67 Koice, Czechoslovakia.     

\alpha-decay spectroscopy of light odd-odd Bi isotopes - I: 188,190Bi nuclei

Detailed fine-structure -decay studies of ^188,190Bi were performed using the complete-fusion reactions of ^50,52Cr ions with a ¹⁴²Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil- , recoil- - /X-ray and excitation function measurements. Improved data on the -decay of ^188,190Bi were obtained and a number of new low-lying excited states in the daughters ^184,186Tl were observed. An intruder, presumably 10^- state was identified in ¹⁸⁴Tl, extending the systematics of such states in the odd-odd Tl nuclei beyond the neutron mid-shell at N = 104. Some technical aspects of experiment at recoil separators are also discussed.Received: 14 March 2003, Revised: 1 May 2003, Published online: 2 September 2003PACS: 23.60.+e decay - 27.70.+q - 27.80.+w C.D. OLeary: Present address: Department of Physics, University of York, York, UK.M.J. Taylor: Present address: Department of Physics and Astronomy, Rutgers Univesity, NJ, USA.L. Weissman: Present address: NSCL, Michigan State University, East Lansing, MI 48824-1321 USA.K. Heyde: Present address: EP-ISOLDE, CERN, CH-1211, Geneva 23, Switzerland.     

A mass zero cluster expansion

A cluster expansion is developed and applied to study the perturbation ()⁴ of the massless lattice field in dimension 3. The method is loosely inspired by the work of Gawedzki and Kupiainen on block spin techniques for the system. The cluster expansion is given in terms of expansion coefficients for the field as a sum of certain special block spin functions. These functions are chosen with a large number of moments zero, so that the interaction couples spatially separated functions with an interaction falling off as a high inverse power of the separation distance. The present techniques, with some technical development, should work for broad classes of other models, including the lattice dipole gas and the model. Models (,,^; )^2s , >1/2, are essentially included in the present work.This work was supported in part by the National Science Foundation under Grant No. PHY 79-05688     

Electronic absorption spectra of hydrogenated quinolines in various solvents

Data are given on _max and _max for dihydro- and tetrahydroquinolines in various solvents. The effects of structure on molecular interaction are discussed.     

The crystal structure of copper dipyridine dibromide Cu(C5H5N)2Br2

The X-ray structural analysis of copper dipyridine dibromide was carried out. The substance is monoclinic, its space group isP2₁/n, having the lattice constantsa=8.30 kXU,b=17.72 kXU,c=4.04 kXU,=96°,Z=2. The localization of the heavy atoms was carried out by means of the projections of the Patterson functionsP(u, v) andP(v, w), which provided the bases for determining the signs of the majority of structure factors. The projections of the electron density(x, y) and(y, z) were calculated on the basis of these data. The positions of the atoms were refined three times by methods of differential syntheses and by geometrical analysis. The structure of CuPy₂Br₂ is very close to that of CuPy₂Cl₂ [1], [2], differing from it primarily in the orientation of the symmetry elements with respect to the crystallographic axes. In both structures the copper atom is octahedrally coordinated with four halogen and two nitrogen atoms. The nitrogen atoms and two bromine atoms are bound to the copper covalently in the structure of the bromine derivative, as follows from the length of the bonds (Cu-N 1.99 kXU, Cu-Br, 2.46 kXU), while the remaining two bromine atoms are bound to the copper by weaker bonds and mediate the chain formation of molecules in the direction of thec axis.

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Cu(C₅H₅N)₂Br₂

. , 2₁/ ==8,30 kX,b=17,72 kX,=4,04 kX,=96°,z=2. (, v) P(v, w), . (, ) (, z). . CuPy₂Br₂ u₂1₂, . . , (-N 1,99 kX, u-r 2,46 kX), .

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The authors thank M. Serátor for supplying the crystal samples and for initiating the work, the management of the Institute of Technical Physics, Czechoslovak Academy of Sciences, in Prague and especially Dr. A. Línek for making it possible to calculate some of the Fourier maps on the special computer Elika and finally A. lechtová for carefully calculating the Fourier maps and structure factors.

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The first stage of this work was reported on at the 3rd State Conference on Inorganic Chemistry, held in Bratislava from June 29th to July 4th, 1959.     

Studium der photodielektrischen Erscheinung an lumineszierenden Zinkkadmiumsulfiden

Zusammenfassung Die spektrale Abhägigkeit der photodielektrischen Eigenschaften der lumineszierenden Zinkkadmiumsulfide verschiedener Zusammensetzung zeigt, da eine Beimengung von Kupfer das Eintreten von Zuständen mit groer Polarisierbarkeit hervorruft, die eine Änderung der realen Komponente der Dielektrizitätskonstanten zur Folge haben. Die Kupferkonzentration kann dabei so gering sein, da sie in der Lumineszenzemission gar nicht zur Geltung kommt. Die Infrarotmaxima der Verluste entsprechen Niveaus, die von anderen Autoren und mit anderen Methoden festgestellt wurden. Das Maximum des Exzitationsspektrums im Bereiche des Ausläufers der Absorptionskante hängt mit dem Maximum der Änderung der realen Komponente der Dielektrizitätskonstante zusammen.

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- , , . , . , . .

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Nunmehr im Physikalischen Institut der Karlsuniversität, Prag.     

КОРРЕКЦИОННЫЕ ФАКТО РЫ ПРИ АБСОЛЮТНОЙ ДОЗ ИМЕТРИИ ПЛОСКИХ ИСТОЧНИКОВβ-ИЗЛУЧЕНИЯ С ПОМОЩЬЮ СЧЕТЧИКА ГЕЙГЕРА-МЮЛ ЛЕРА

n n, n , .     

К ТЕОРИИ ГРАВИТАЦИОННОГО ИЗЛУЧЕНИЯ

. , , , . , . . . . , , . ; , .

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On the theory of gravitational radiation

The equations of motion of weakly radiating particles are investigated in a linear approximation in which the pseudo-Euclidian metric remains valid but energy changes caused by gravitational radiation are considered. The classical relativistic equations of motion with variable rest mass are applied. An elementary theory of the gravitational radiation of a rotator is formulated. The results are applied for particles in circular accelerators. It is found that a rotator with non-zero rest mass cannot exist for an unlimited period and that it cannot exceed the velocity of light. This explains why particles with non-zero rest mass cannot attain the velocity of light in circular accelerators; it is also shown that the gravitational radiation of particles in circular accelerators does not exist in practice.

     

К ВОПРОСУ O КРИТИЧЕСКО Й ЧАСТОТЕ ПРИ ПРЕРЫВИСТОМ ОСВЕ ЩЕНИИ

c , c n , n AgBr. .