Zur Temperaturabhängigkeit der Rechteckigkeits-Koeffizienten der Mangan-Magnesium-Ferrite

Ohne Zusammenfassung

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Abschließend danken wir der Kollegin A. Hadincová für die mit Sorgfalt durchgeführten Messungen.     

ФОТОЭЛЕКТРИЧЕСКИЕ С ВОЙСТВА АНТИМОНИДА ГАЛЛИЯ

(GaSb), - 120–340 °K. : E₂=(0,773–0,75.10^–6 T ²) ., - .     

New derivation of Bardeen-Shockley formula for mobility of electrons in homopolar semi-conductors

The Bardeen-Shockley formula for the mobility of an electron or hole in a homopolar semi-conductor is derived in a different way to that in which its authors obtained it. The interaction energy of the electron with the acoustic lattice oscillations is derived in an original way. A new possibility for determining the energy gap is given.

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- , , , . . .

     

Gerät zur Messung der Magnetostriktion Durch eine VerÄnderliche Kapazität

Ohne Zusammenfassung

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Die durch eine Belastung induzierte amplitudenabhängige innere Reibung bei Fe-Ni Legierungen

Ohne Zusammenfassung

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Fe-Ni ,

     

Energy relations in sound propagation in porous materials with rigid skeleton

The paper deals with the determination of the frequency dependence of the acoustic resistance, of the structure factor, the porosity factor and the constant giving whether the process in the propagation of sound in porous materials with a rigid skeleton is isothermal, adiabatic or polytropic. The latter dependence enables a conclusion to be reached on the energy relations during sound propagation in porous materials.The derivation of the wave resistance and of the constant of wave propagation in a porous material with a rigid skeleton is given and a method described for calculating the constants characterizing the material on the basis of measurements of the wave resistance and the acoustic impedance of the material. The calculation was carried out for felt and it was found that the acoustic resistance and structure factor depends on the frequency and that the process at low frequencies approaches the isothermal and at high frequency the adiabatic. It is shown that the structure factor is not equal to unity even in order of magnitude, as is often assumed in the literature. It is shown that for a complete knowledge of the acoustic resistance necessary for the calculations it is not enough to determine it by the static method.

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The work was carried on through the cooperation of the Research Institute of Sound, Image and Reproduction Technique and the department of physics at the Electrotechnical Faculty of the Czech Technical University in Prague. The authors would like to thank Prof. J. B. Slavík, head of the department of physics, and M. Jahoda, director of the Research Institute of Sound, Image and Reproduction Technique, for the attention they paid to this work.     

The elastic coupling between longitudinal and transversal vibrations оf isotropic rods II. Rods of circular cross-section

The new approximative method for calculating the frequencies of longitudinal vibrations of isotropic homogeneous rods described in part I. is used for rods of circular crosssection. Similarly to the rods of rectangular cross-section there does not exist any dead zone of frequencies.

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II.

, I. (. . 366), . , , .

     

Le pouvoir résolvant du système „objectif-émulsion“

Sans résumé

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Variante Einer Neuen Sphärometrischen Methode

Ohne Zusammenfassung

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On the mechanism of rendering visible dislocations on the surface of iron crystals by anodic dissolving

The paper contains further results of studying dislocations rendered visible by anodic dissolving on the surface of single crystals of alpha-iron. The influence of the crystallographic orientation of the surface is investigated, the effect of carbon is confirmed and the anodic process is studied. The mechanism of dissolving of the crystal is given and a new more suitable method of rendering dislocations visible is derived.

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The author thanks F. Kroupa and J. Hejduk for critical remarks and discussion.     

Über die Natur der Magnetomechanischen Erscheinung im Wechselmagnetfeld

Ohne Zusammenfassung

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Die Schmelzpunkte des Gallium- und Indiumantimonids

Ohne Zusammenfassung

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Der Einfluss verschiedener Beimischungen auf die Entstehung der Leinen und Baumstruktur in der Glimmentladung in der Atmosphere Luft-Quecksilberdampf

Ohne Zusammenfassung

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Zum 75. Geburtstage von Prof. Dr. Josef Zahradníček

Ohne Zusammenfassung

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75-

     

Bemerkung zur Arbeit von L. ?pa?er: Die Struktur der Oberfl?chlichen Abschlussbereiche in den (100) Ebenen in Eisen [4]

Ohne Zusammenfassung

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L. paek (100)

     

Tage des tschechoslowakischen Hütten- und Giessereiwesens in Pilsen

Ohne Zusammenfassung

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Circular edge dislocation loop

A solution of the stress, deformation and deformation energy is given for an edge dislocation with its dislocation line having the shape of a circle in an unlimited isotropic medium. The possibility of using this solution in studying the dislocation loop in a crystal is discussed.

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The author thanks M. imanová for carrying out the numerical calculations and J. Kaczér and B. esták for remarks and discussion.     

Some applications of the discrete fourier transform to problems of crystal lattice deformation II

The method elaborated in [1] is applied to the solution of some problems for a plane lattice and the linear chain. The method can be used to investigate deformations around crystal lattice defects.

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, [1] . .