On longitudinal vibrations of thin cylindrical tubes

The method of variable coupling parameters is used for approximatively calculating the frequencies of longitudinal vibrations of isotropic homogeneous tubes. For thin-walled tubes we arrive at the same formula for frequencies as in Love's classical theory.

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. , .

     

The use of the kramers-kronig relations in determining optical constants

The paper discusses some of the ways in which to avoid difficulties in applying dispersion relations to experimental data of the optical constants of solids, particularly with regard to measurements in a narrow frequency range.

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-

.

     

The conversion electron spectra of Lu169 and Lu170

The isotopes Lu¹⁶⁹ and Lu¹⁷⁰, obtained in the fraction of radioactive Lu isotopes by bombarding a Ta target with fast protons, were measured on a double focusing -ray spectrometer. The gamma transitions are given together with the relative intensities of the conversion lines. The multipolarity of the transition is determined for some gamma transitions from the internal conversion coefficient ratios of theK andL shells.

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Lu¹⁶⁹ Lu¹⁷⁰

Lu¹⁶⁹ Lu¹⁷⁰, . - . - K L .

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We should like to thank V. Kopiva and M. Buriánek for help during the measurements.     

The effect of oxygen on the electric conductivity of a cuprous oxide single crystal

The effect of an excess of oxygen on the electric conductivity of a pre-illuminated and heated single crystal of Cu₂O is investigated. It is found that the influence of illumination on the electric conductivity, together with the concentration of impurities, increases with increasing oxygen pressure during annealing.

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, Cu₂O. , .

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In conclusion the author thanks E. Klier and J. Pastrak for valuable remarks and discussion.     

The influence of plastic deformation on the magnetostriction constant of iron-nickel alloys

The magnetostriction constant of three iron-nickel alloys and one Fe-Ni-Co alloy was measured as a function of the plastic elongation up to about 25%. The magnetostriction constant decreases with deformation in all materials. In Fe-Ni-Co alloy the volume magnetostriction also decreases. The influence of crystallographic texture is discussed and it is shown that it is not a decisive factor. The observed decrease is explained by assuming the influence of lattice deformation on spin-orbital interaction.

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- Fe-Ni-Co 25%. . Fe-Ni-Co . , . .

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In conclusion the authors thank Z. Málek and S. Libovický for carefully reading this paper and for remarks, J. Míová for help in the measurements, J. Cáslavský for X-ray determination of the texture and members of the chemical department of the Institute of Physics for thermal treatment and analysis of the samples.     

RÄumliche Darstellung der Atomverteilung im Kristallgitter aus einer beschrÄnkten Anzahl von Röntgendiffraktionsdaten

Zusammenfassung Aus den Projektionen der Elektronendichten in drei voneinander unabhÄngigen kristallographischen Ebenen wird die Funktion (2) zusammengesetzt, die das übliche Darstellungsverfahren mit Hilfe der dreidimensionalen Fourierreihe ersetzt.

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(2), .

     

Arbeitstagung über die Physik und Chemie der Kristallphosphore in Berlin

Ohne Zusammenfassung

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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.     

Untersuchungen über Versetzungen an Einkristall- und Polykristallplatten von AgCl

Zusammenfassung Beobachtungen der Versetzungen wurden an für optische Messungen hergestellten Platten des AgCl gemacht. Es wurde die Versetzungsdichte im Zusammenhang mit dem deformierenden Druck untersucht.

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AgCl

AgCl, . .

     

Graphische Bestimmung der optischen Konstanten aus Zwei DurchlÄssigkeiten

Ohne Zusammenfassung

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Determination op energy gap width in some semi-conductors

The formula derived by the author for the width of the energy gap is compared with experiment for GaSb, InAs, InSb, and InSb. GaSb semi-conductors. The agreement is good.

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GaSb, InAs, InSb, InSb. GaSb. o.

     

Double cascade transitions of gamma rays from radiative capture on Co59

Pairs of gamma quanta, giving a sum equal to the binding energy of the last neutron in a Co⁶⁰ isotope, were studied during radiation capture on a Co⁵⁹ nucleus. The energies of the gamma quanta giving such cascades were determined and an attempt was made to determine the relative intensities of the different cascades.

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- Co⁵⁹

Co⁵⁹ -, Co⁶⁰. -, , .

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In conclusion the authors thank J. Vávra for cooperation in the measurements.     

Influence of manganese and oxygen content on tetragonal deformation of copper ferrite

Pure copper ferrite and solid solutions of 0.9 parts of copper ferrite CuFe₂ and 0.1 part of hausmannite Mn₃ were heated in air or in oxygen at various temperatures and either cooled slowly or quenched. All samples with cubic spinel structure contained less oxygen than required by the ideal spinel formula Me²⁺Me ₂ ³⁺ O ₄ ^2– . The addition of hausmannite promotes the formation and/or stabilization of the cubic structure. The lower the heating temperature, the higher the oxygen deficiency necessary for the preparation of cubic samples.

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CuFe₂O_4– Cu_0,88Mn_0,30Fe_1,82O_4± Cu_0,91Mn_0,31Fe_1,82O_4± . , <0; , , (4±) ( ) . Cu-Mn ( –) ó, . , CuFe₂O_4– . ; .

     

Characteristic parameters of recombination centres

The paper points to the possibility of describing the properties of recombination centres by means of the quantitiesc _p/c _n ande _n/e _p, in contrast to the existing method based mainly on the so-called energy position of recombination levels. The proposal is supported by a simple statistical analysis and by experimental material and has some advantages over the method used hitherto.

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c _p/c_n e _n/e_p , . .

     

A possible test of quantum electrodynamics by means of polarization effects in electron-nucleon scattering

The differential cross-section is given for the electromagnetic scattering of polarized relativistic electrons on polarized nucleons. The finite size of each particle is taken into account by means of two form-factors. The effect of the possible non-punctiform structure of the electron on the polarization effects in scattering is discussed. It is shown that the internal structure of the anomalous magnetic moment of the electron would show itself in the cross-section by terms depending on the transversal polarization of the incident electrons.

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. . . , , .

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Summary of results of a diploma-thesis for the degree of graduate physicist.

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In conclusion the author wishes to express his sincere gratitude to prof. V. Votruba and J. Kvasnica for suggesting this problem, for helpful discussions and valuable advice.     

Bestätigung der Hertzschen Theorie mittels eine indirekte Methode

Ohne Zusammenfassung

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Die Linearitätsabweichung des Fermi-Diagramms bei P32

Ohne Zusammenfassung

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P³²

     

Die Konferenz über optik und Spektroskopie aller wellenlängen in der DDR

Ohne Zusammenfassung

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Der Einfluss von Mikrosegregations-Substrukturen auf die Kritische Schubspannung und den Verfestigungskoeffizient von Zinkeinkristallen

Zusammenfassung Der Einflu\ von Mikrosegregations-Substrukturen auf das plastische Verhalten von Zinkeinkristallen entspricht den allgemeinen Erwartungen in der Weise, da\ die kritische Schubspannung mit wachsender Substrukturendichte zunimmt. Der Verfestigungskoeffizient _A nimmt hingegen mit wachsender Substrukturendichte ab. Dabei wird der Verfestigungskoeffizient vom Charakter der Substruktur viel empfindlicher beeinflu\t als die kritische Schubspannung. Es wird angenommen, da\ dieser Einflu\ durch unterschiedlichen Fremdstoffgehalt zustande kommt.

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, . , _A . , . , .

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Die Autoren danken Herrn Prof. M. Valouch, der die Durchführung dieser Arbeit ermöglicht hat. Herrn P. Kratochvíl sei an dieser Stelle für zahlreiche Diskussionen aufs herzlichste gedankt.     

Zur Frage derZ-Zentren bei der Exoelektronenemission aus Alkalihalogeniden

Zusammenfassung Es wurde das Maximum des Exoelektronenemissionsstroms untersucht, das an NaCl infolge Verunreinigung durch Kalzium auftritt, und die Möglichkeit, dieses Maximum denZ-Zentren zuzuordnen, diskutiert.

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Z-

, NaCl . Z-.

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Wir danken herzlichst Herrn Dr. A. Bohun für das gefällige überlassen des NaCl: Ca-Materials.