Zur Abhängigkeit der Wärmeleitzahl von Gasen und Flüssigkeiten vom Druck und von der Temperatur

Ohne Zusammenfassung

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Thermoemission und Photoemission von Natriumchlorid

Ohne Zusammenfassung

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Nacl

     

Zur Labyrinthstruktur bei Martensit

Ohne Zusammenfassung

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Verfärbung und Lumineszenz bei Korund

Ohne Zusammenfassung

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Auszug aus dem am 4. 11. 1954 auf der Konferenz über Einkristalle in Turnov vorgetragenen Referat.     

Spatial period of moving striations as function of electric field strength in glow discharge

During a systematic investigation of the parameters of a moving stratification in a glow discharge in helium and neon it was found that the spatial period of the striations is a simple, unique function of the d-c (constant) component of the longitudinal electric field strengthE. It was found that this dependence is hyperbolic and that the simple relation (1) or (2) thus holds. In the relation has the significance of a potential fall between the corresponding points of two neighbouring striations and in the measured range of pressures, currents and diameters of discharge tubes it depends only on the sort of gas and type of striations.

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, , E. , , , (1) (2). (1) (2). , .

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The principal results of this work were reported at the 1st conference on electronics in Prague on April 26, 1960.     

The electroluminescence op ZnS-Cu single crystals excited with pulses of alternating polarity

The brightness waves of electroluminescence of ZnS—Cu were measured for the case of excitation with rectangular pulses as a function of the amplitude of the pulses and the temperature. A concrete model is proposed for electronic processes in barriers in ZnS crystals, the consequences of which for the decay of electroluminescence are in agreement with measurements.

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ZnS-Cu,

e ZnS-Cu . ZnS-Cu, .

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In conclusion the author thanks M. Trlifaj for valuable remarks and discussions, Z. Vojta and E. Rechziegel for constructing an important part of the apparatus and F. Karel for the electroluminescent crystals.     

Die Veränderung einer Metalloberfläche nach der Elektronenemission unter atmosphärischen Bedingungen

Ohne Zusammenfassung

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The distribution of neutron density in the vicinity of a partly inserted black rod in two-group approximation

The neutron density in the vicinity of a black cylindrical rod partly inserted in a bare reactor is calculated and illustrated by a numerical example. The starting point is a two-group diffusion theory approximation. While the dependence of the effect of the rod on the insertion depth can be calculated simply by means of perturbation theory, the question of the neutron density estimate in the vicinity of the rod is considerably more difficult and in some considerations the estimate of the neutron density caused by the presence of the rod is indispensable. The method makes it possible to determine the reactivity value of the rod in dependence on the insertion depth and especially the neutron density deformation in the vicinity of the rod.

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()

. , . , , . , . [1] . .

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In conclusion the author thanks J. Svato for help in carrying out the numerical calculations.     

Über den Einfluss von Stickstopf auf die Exoelektronenemission von Germanium

Zusammenfassung Es wurde der Einfluß eines Bombardements mit Stickstoffionen vor der Erregung untersucht und gezeigt, daß die Stiekstoffatome eine große Rolle bei der Entstehung des Emissionsmaximums bei 150° spielen.

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-

, 150°C.

     

Zum Verlauf der Abhängigkeit der Koerzitivkraft von der plastischen Deformation

Ohne Zusammenfassung

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Der Einfluss der Schlagdeformation auf das Entstehen von Martensit-Plättchen

Ohne Zusammenfassung

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On the relation between the thickness dependence of optical absorption and the surface layers of barium titanate single crystals

Single crystals of BaTiO₃, prepared by crystallization in the system BaCl₂-BaO-BaTiO₃-show a dependence of the optical absorption coefficient on the sample thickness. The observed thickness dependence of the absorption coefficient can be explained by the existence of a surface layer with optical properties differing from those of the inner part of the crystal. By means of an etching method a direct determination of the thickness of the surface layer of crystals in the thickness range of 0.075 to 0.178 mm was carried out. The value found is (6.0±0.2)×10^-4 cm.

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iO₃, 1₂-BaO-BaTiO₃ . . 0,075 0,178 mm. (6,0±0,2). 10^-4 cm.

     

Thermostimulierte Exoemission und Lumineszenz von MgO und CaO

Ohne Zusammenfassung

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MgO CaO

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Ich danke bestens Frau K. Listoová für die sorgfältige Durchführung der Versuchsreihen und Ing. S. urovi und Dr. A. Bergstein für das liebenswürdige Überlassen der Präparate.     

The quantum efficiency of the internal photo-electric effect in indium antimonide

A method is described for measuring the relative quantum efficiency of the internal photo-electric effect in semi-conductors by simultaneously measuring the photo-magnetoelectric and photo-conductive effect. The results of measurements on indium antimonide are given. The quantum efficiency begins to increase if the energy of the photon exceeds 0·47 eVat room temperature. The quantum efficiency as a function of the energy of the photon is analysed on the basis of the conception of impact ionization and it is shown that a study of the structure of this curve can supply information on the, band structure of a semi-conductor in the region of high energies of electrons and holes.

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. . , 0,47 eV . , .

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The authors thank M. Závtová and M. Vantuchová for efficient help with the measurements, K. mirous and V. Vrchovská for preparing the material, E. Antoník for critical remarks and M. Matyá and A. Müller for determining the constants of the material.     

Das Anhaften von Exzitonen an Störstellen des Kristallgitters

Zusammenfassung Es wird der Proze des Anhaftens von Exzitonen an Vakanzen und F-Zentren in den Ionenkristallen studiert. Die Bewegung der Exzitonen im Felde der Vakanz und des F-Zentrums wird in adiabatischer Annäherung untersucht. Mit Hilfe der klassischen Methoden werden die Wirkungsquerschnitte des Anhaftens des Exzitons an den Vakanzen und F-Zentren bestimmt und diskutiert.

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F- . F- . F- .

     

Abhängigkeit des Torsionsmoduls von stahl von der Torsionsvorspannung

Ohne Zusammenfassung

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Über die Natur der Magnetomechanischen Erscheinung im Wechselmagnetfeld

Ohne Zusammenfassung

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Zum Problem der Exoelektronenemission

Ohne Zusammenfassung

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The diffusion and non-radiative transfer of excitation energy in molecular crystals containing foreign molecules

A study is made of the non-radiative transfer and diffusion of excitation energy in molecular crystals containing foreign molecules and its influence on the luminescent properties of these crystals.

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,

, .

     

The probability distribution of the velocities of gas molecules after collision with a rapidly moving rigid body

The above problem is met, for example, in the case of the collision of molecules of the atmosphere with an artificial earth satellite and leads to the problem of determining the probability distribution of the absolute value of the vector sum of a constant vector and a Maxwell vector (the latter being a vector, whose rectangular components are distributed normally, with the same standard deviation and mean value zero). The resultant probability density is given by equation (18), the complement to the distribution function by (24), the mean value by (27) and the variance by (31). These results are obtained by transforming the corresponding three-dimensional normal distribution to spherical co-ordinates and integrating over the co-ordinate angles and , which yields the required probability density; the other results are then obtained from it by the usual methods.

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, , (. . , ). (18), -(24), -(27) (31). , ; .