New proof of a characterization of geodetic graphs

In [3], the present author used a binary operation as a tool for characterizing geodetic graphs. In this paper a new proof of the main result of the paper cited above is presented. The new proof is shorter and simpler.     

Pathological behavior of renormalization-group maps at high fields and above the transition temeprature

We show that decimation transformations applied to high-q Potts models result in non-Gibbsian measures even for temperatures higher than the transition temperature. We also show that majority transformations applied to the Ising model in a very strong field at low temperatures produce non-Gibbsian measures. This shows that pathological behavior of renormalization-group transformations is even more widespread than previous examples already suggested.     

Mass,internal energy,and Cauchy's equations in frame-indifferent thermodynamics

Communicated by D. Owen     

Planning in physics

Following some introductory notes on science, a brief summary of the structure, contents and principal aims of the State Plan of Scientific Research currently being fulfilled in Czechoslovakia is given. More specifically, the different tasks and extent of work done under the State Plan in physics are described, the relative weight of this field compared to other regions of the plan is evaluated and certain long-term trends are mentioned. In the closing chapter an attempt is made to review the most interesting opinions on various aspects of contemporary physics research and its relations to society.     

Mixing ratio of the 0.34 MeV (M1 + E2) transition in49Ti

A direction-polarization correlation experiment was carried out in order to remove the ambiguity of the mixing ratio of the 0.34 MeV transition in⁴⁹Ti. The result of this experiment gives sufficient proof that the value is=+0.1.The authors wish to thank Mr. J. Holeek for his continuous help with the measurements and Ing. R. Michalec as well as other members of the Neutron Physics Department of our Institute for their interest and many helpful discussions.     

Painlevé classification of semilinear partial differential equations

The Painlevé-type classification of first degree second-order polynomial PDEs is performed.     

Beitrag zur spektrophotometrischen Aluminiumbestimmung mit Xylenolorange

Zusammenfassung Die Möglichkeit der Anwendung von Xylenolorange zur spektrophotometrischen Aluminiumbestimmung wurde nachgewiesen. Das optimale p_H wurde ermittelt, die Komplexbeständigkeit und der Einfluß von Begleitstoffen verfolgt. Ein Arbeitsverfahren zur Aluminiumbestimmung in Säuren, Laugen und Wässern wurde vorgeschlagen.

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Summary The feasibility of employing xylenol orange for the spectrophotometric determination of aluminium was established. The optimum p_H was determined, and the stability of the complex and the effect of accompanying materials were followed. A procedure was suggested for determining aluminium in acids, caustic solutions, and waters.

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Résumé On a étudié la possibilité d'appliquer l'Orangé Xylénol au dosage spectrophotométrique de l'aluminium. On a déterminé le p_H optimal et étudié la stabilité du complexe et l'influence des substances qui l'accompagnent. On propose un mode opératoire pour le dosage de l'aluminium dans les acides, dans les lessives alcalines et dans les eaux minérales.

     

On the accuracy of WKB analysis of TE and TM modes in planar graded-index waveguides

The TE and TM mode spectra in inhomogeneous optical waveguides with various refractive index profiles have been calculated in the WKB approximation and compared with data obtained numerically from rigorous theory. The effective index errors better than 3 × 10^-4 and 1.5 × 10^-3 have been found for unburied profiles, respectively. The results obtained may help to take full advantage of the WKB analysis for practical purpose.     

Spektrale Momente und Charakteristische Debyefrequenzen von Diamantartigen Halbleiterverbindungen

Moments of frequency spectrum and Debye characteristic frequencies are taken from literature or are calculated, using the data of specific heat, Debye characteristic temperatures, and mean square atomic displacements of the fourth group elements and compounds with sphalerite structure. The typical features of the Debye characteristic frequencies of these substances are shown and discussed. The results of some theoretical and experimental determinations of latticce dynamical properties of these substances are compared and estimated by means of the dependene of the Debye characteristic frequencies on the order of the moments of frequency spectrum.