Stationary states of an electron in the field of a hole in an ionic crystal

An approximate solution is given of the Schrödinger equation for S-states of an electron in the field of a hole, when the potential energy of the electron has the form — e²/r [1+exp (–qr].

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s- , –e²/r [1+exp (–qr].

     

Ховый метод измерени я коэфициента отражния

, , . .

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A new method of measuring the reflectivity factor

A new method is given of measuring reflectivity and compared with methods known up to now, which are characterized briefly. The applicability and suitability of the given method is shown on an example of measurement of the reflectivity of germanium in the ultra-violet and visible regions.

     

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.     

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.     

ФРЕНЕлЕВскИЕ И ЁНЕРг ЕтИЧЕскИЕ кОМплЕксН ыЕ АМплИтУДы В ОптИкЕ тО НкИх МЕтАллИЧЕскИх с лОЕВ

The Airy summation formulae for the real amplitudes can be written in the two ways: 1) with Fresnel amplitudes, 2) with energy amplitudes. Both ways lead to the same formulae and results. In the case of the reflection and transmission of light through a thin metallic film the Airy summation formulae can be also written in two ways: 1) with Fresnel complex amplitudes, which follow from the boundary conditions, 2) with energy complex amplitudes, which are determined by the Stokes principle of reversibility. The two ways lead to different formulae and results. The author proves that only the energy conception of the complex amplitudes is correct, because it expresses the complete energy balance on both boundaries of a thin metallic film. If we start these calculations from the Fresnel complex amplitudes, then when the light passes from the metal to the dielectric the energy balance does not express the interference intensity. It is from this point of view that Drude's method for the derivation of the formulae for the reflection and transmission of light through a thin film is evaluated, which is correct only for a thin dielectric film (for real amplitudes), but Drude's method fails for a thin metallic film, where the corresponding amplitudes are complex. Drude's method does not take into account the interference intensity on both the boundaries, metal and dielectric.

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, . M. B. 23. 1962 .

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, .     

Refining of CdSb and preparation of CdSb single crystals by zone melting

CdSb single crystals were prepared by zone melting in a boat both with and without a seed crystal in a stream of pure hydrogen or in a sealed and evacuated tube. The zone moved with a velocity of 1–20 cm/hour. Zone melting in an evacuated tube was used to prepare CdSb single crystals of high purity containing 10¹⁵ acceptors/cm³ at room temperature. During zone refining the stoichiometry is damaged; the front part of the ingot is enriched by cadmium and the end of the ingot by antimony; the enrichment is of an order of several percent after 10 passages of the zone. In the middle part of the ingot the stoichiometric compound remains unchanged. CdSb single crystals grow even by directional cooling of the melt of the stoichiometric compound without a seed crystal.

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CdSb CdSb

CdSb 1–20 cm/, . CdSb CdSb , 10¹⁵ cm³ . ; , . . . CdSb .

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The author died 28. 5. 1961.     

ВЛИЯНИЕ ПОЛНОГО ОТРА ЖЕНИЯ НА ДИАФРАГМЕ СОЛЛЕРА НА РАЗРЕШАЮШ УЮ СИЛУ РЕНТГЕНОВСКО ГО СПЕКТРОГРАФА

- - , , , . - , -.     

The collisions of two plasma streams

The mutual interaction of two colliding plasma streams is investigated by means of the perturbation method. The disordered random motions of electrons are taken into account. It is shown that electron oscillations occur only when certain conditions as to the density and relative velocity of the colliding streams are fulfilled. The order of magnitude of the thickness of the shock generated by the initial relative motion is estimated on various assumptions.

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. . , , . , , .

     

Study of magnetic after-effect in magnesium manganese ferrites

The magnetic after-effect caused by the diffusion of electrons was studied in detail in MnMg ferrites of the series Mg _x Mn_1.15–x Fe_1.85O₄₊ ; the comparative measurements were also carried out on a sample of MgFe₂O₄₊₍<0). By combining the two methods, (a) investigation of the disaccommodation of initial permeability at different temperatures and (b) measurement of the displacement of the maximum of the temperature dependence tan with the frequency, it was possible to study the relaxation processes whose time constants lay between 0.5 sec and several hours, or between 10^–4 to 10^–7 sec. It was found that the processes taking place at low temperatures and studied by method (a) differ from those observed at high temperatures by method (b), particularly in the lower activation energies and greater dispersion of the time constants. In addition to these two main relaxation processes a weak relaxation superposed over the main disaccommodation was found in ferrites with non-zero content of manganese. An analysis of the intensity of different relaxation effects showed the participation of Mn ions in these relaxation effects and it was found that both main relaxations are probably equivalent as regards the final steady state, to the creation of which they lead; they differ however in the mechanism of electron diffusion by which this state is realized. The main features of the different diffusion mechanisms are discussed.

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, , MnMg Mg _x Mn_1.15–x Fe_1.85O₄₊ . MgFe₂O_{4+ (}<0). ()- , () tg , , 0,5 sec , 10^–4–10^–7 sec. , , () , , (), , , . , . Mn , , , , , ; , , , . .

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In conclusion the author thanks Dr. J. Bro and K. Závta for valuable discussion and F. Vilím for carefully carrying out the measurements.     

Single crystal diffraction pattern of germanium

The diffraction pattern for the (111)-reflection of germanium was measured by means of the three-crystal arrangement and compared with dynamical theory. The results obtained indicate the possibility of using germanium crystals for precise measurements in X-ray spectroscopy.

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(111) . .

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In conclusion the authors thank Ing. Hrubý for preparing the germanium single crystals and participating in the preparation of the surfaces; they are also indebted to V. Smutná, R. ída and A. Irra for the care with which they carried out various tasks and V. Horáková for carefully performing the numerical calculations.     

Измерение некоторых нейтронных спектров методом ядерных эмулъсий

. Ra+Be . , , . 8.     

К ВОПРОСУ О ФОТОПРОВО ДИМОСТИ ФОТОГРАФИЧЕСКОЙ ЭМУ ЛьСИИ

) . , , , ; , , . . , .     

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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. , .

     

Влияние непроводяще го слоя на поверхност и электродов на ход эле ктрического конденсированного р азряда

, .     

Studium der Stationären und Laufenden Schichtung in der Entladung in Neon Mit Hilfe eines Lokalen Hochfrequenzfeldes

Zusammenfassung Es wurde ein Verfahren zur Erregung von stationären Schichten, der Schichtungswelle und der laufenden Schichten in der Gleichstromentladung ausgearbeitet, das auf der Einwirkung eines Hochfrequenzfeldes auf einen kurzen Abschnitt der positiven Säule beruht. Dieses Verfahren wurde zum Studium aller drei angeführten Schichtungsarten in Neon benützt, insbesondere jedoch zum Studium des Zusammenhanges zwischen den laufenden und den stationären Schichten.Bei stationären Schichten wurden zweifache Strukturen festgestellt und es wurde deren Abhängigkeit vom Entladungsstrom und von der Größe des erregenden Hochfrequenzfeldes verfolgt.Bei der Schichtungswelle wurde die Stelle deren Entstehung ermittelt und es wurde nachgewiesen, daß das Hochfrequenzfeld diese Welle lokal an der Stelle dessen Einwirkung auf die positive Säule hervorruft.Bei den laufenden Schichten wurde deren Resonanzfrequenz in Abhängigkeit vom Entladungsstrom und die Abhängigkeit der Wellenlänge der Schichten von der Frequenz untersucht.Es wurde festgestellt, daß der extrapolierte Wert der Wellenlänge für die Nullfrequenz erheblich niedriger ist als die Länge der stationären Schichten. Weiter wurde eine Übereinstimmung der Frequenz der laufenden Schichten in der Schichtungswelle mit der Resonanzfrequenz der künstlich hervorgerufenen laufenden Schichten festgestellt.

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, , . , . . , . . , . , .

     

ВЛИЯНИЕ ПАРНЫХ СИЛ НА ЭНЕРГИЮ ГИГАНТСКОГО РЕЗОНАНСА

, , . .

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Influence of pair forces on the giant resonance energy

The influence of various nucleon-nucleon forces on the giant resonance energy is investigated with the help of the sum rules. The dependence of the contribution of exchange forces to the integral cross-section of the gamma quantum absorption on the number of protons and neutrons is obtained for light nuclei.

     

Рентгенографически е измерения остаточн ыгх напряжений в керамич еских изоляторах из плавленного корун да

Al₂O₃ K ₁ . , , .     

РЕНТГЕНОВСКОЕ ИЗЛУЧ ЕНИЕ, ВОЗБУЖДАЕМОЕ ПР ОТОНАМИ в Zn,Cu, Ni,Co и Fe

, , - 400–700 Zn, Cu, Ni, Co Fe. NaCl. - -. -. - , - .     

Bemerkung zur Theorie der Elektrolumineszenz in ZnS-Kristallen

Zusammenfassung Nach Zalm sind die Kristalle von ZnS mit einer dünnen Halbleiterschicht bedeckt, aus der auf Grund des Tunneleffekts Elektronen in den Kristall eindringen können. Im vorliegenden Artikel wird vorausgesetzt, da die Elektrolumineszenz bei der Rekombination dieser Elektronen mit den ionisierten Aktivatorzentren eintritt, die sich im Kristall zu Beginn eines jeden Zyklus vorfinden, und die Folgen dieser Voraussetzung werden mit den experimentell erhaltenen Daten verglichen.

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ZnS

ZnS , . , , ; .

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Dieser Artikel entstand aus einer Diplomarbeit, die im Physikalischen Institut der Tschechosl. A. d. W., Prag, ausgearbeitet wurde.

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Abschlieend möchte ich RNDr. Miroslav Trlifaj für seine zahlreichen wertvollen Hinweise wie auch für sein Interesse an dieser Arbeit danken.     

ГАЛЬВАНОМАГНИТНЫЙ Э ФФЕКТ В ОБЛАСТИ ТЕМПЕРАТУРЫ КЮРИ

. - II- . .