On the interaction of two beating electrostatic waves with plasma electrons

This paper is devoted to the study of the interaction of particles with two beating plasma waves. We follow the instructional article by Ott and Dum. According to them, the sum of wave actions during the interaction is constant, supposing the effect of trapped particles on the beat can be neglected. In the present paper, this problem is solved more generally, just for the case of trapped and also untrapped particles in the wave. Our study shows that the sum of wave actions is constant also in the case when the influence of the trapped particles on the amplitudes of two waves was considered. On the contrary this conclusion is not valid if it is supposed that two original waves are amplitude modulated e.g. by the influence of the interaction of the beat with particles. The author is deeply indebted to Dr. Ladislav Krlín for guidance and encouragement throughout the course of this work.     

Effective relaxation time of the impurity concentration in a medium with a slightly nonuniform diffusion coefficient

Based on the previously introduced integral criterion and a new approach to estimating the time characteristics of diffusion, the relaxation time of impurity concentration in a medium with a slightly nonuniform diffusion coefficient is determined. The diffusion coefficient profile that cuts the relaxation time is found.     

Study of the cation distribution in the surface layer and bulk of substituted iron garnet films

A comparative analysis has been carried out of the physical-chemical state of the surface and bulk of single-crystal films of the iron garnet Y_2.6Sm_0.4Fe_3.7Ga_1.3O₁₂ on substrates consisting of a gadolinium-gallium garnet single crystal. To carry out this study, we used the method of simultaneous γ-ray, x-ray, and electron Mösbauer spectroscopy, which made it possible to simultaneously extract information from the surface layers and the bulk of the sample. This method was applied using a precision system for the motion for the Mössbauer source. It is shown that the parameters of the hyperfine interactions in the surface layer and in the bulk of the film differ, and that these differences increase towards the surface. This result is explained by the fact that the surface layer is formed as the substrate, together with the synthesized film, is removed from the flux and, consequently, the temperature conditions of synthesis of the bulk and of the surface layer are different.     

A survey of symmetry point groups and characters of its irreducible representations

In this paper the character tables of irreducible representations of discrete symmetry point groups of general order are arranged.     

Reference materials for PCDD and PCDF analysis: production and verification of the contents of twelve congeners in iso-octane reference solutions

Summary The Community Bureau of Reference (BCR) of the Commission of the European Communities has produced standard solutions of PCDDs and PCDFs (dirty dozen) to guarantee proper calibration and traceability of results in the certification of these compounds in matrix materials. The purity of each individual isomer has been evaluated on the initial crystals using several analytical methods. Solvents have been checked for impurities. The entire procedure of preparation of the twelve solutions has been performed under strict metrological conditions and will be published elsewhere. All results and the preparation procedure followed are described. The solutions are not certified, but may be obtained from BCR together with an analytical report.     

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.     

СПЕКТР КОНВЕРСИОННЫ Х ЭЛЕКТРОНОВ Lu171 И Lu172

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Conversion electron spectrum of Lu¹⁷¹ and Lu¹⁷²

     

Analytischer Entwurf eines Triplets und seiner Modifikationen

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Analytischer Entwurf eines Triplets und seiner Modifikationen