Showing papers in "Czechoslovak Journal of Physics in 1952"
TL;DR: In this article, various methods, most of them highly perfected, are used for the experimental investigation of strain-stress distribution, including photo-elastic methods for investigation on models while electrical strain-gauges are preferred for strain determinations on the original.
Abstract: Various methods, most of them highly perfected, are used for the experimental investigation of strain-stress distribution. Photo-elastic methods are widely used for investigation on models while electrical strain-gauges are preferred for strain determinations on the original.
12 citations
TL;DR: In this paper, the binding energy was calculated and an attempt was made to explain the spectral distribution of the soft X-ray emission spectrum of a magnesium ion with respect to its magnetic properties.
Abstract: Results are given on the calculations of the energetic spectra of valency electrons in metallic magnesium according to the new method suggested by Z. Matyas and on the basis of group analysis of the wave functions of valency electrons in a crystal. The binding energy was calculated and an attempt was made to explain the spectral distribution of the soft X-ray emission spectrum. The author further attempted an explanation of the quantitative changes in the dependence of the lattice constant of some solid solutions of multivalent metals in magnesium. In all cases the agreement with experiment is satisfactory.
12 citations
TL;DR: In this article, the Schrodinger equation is solved by means of the perturbation theory with the help of certain approximate wave functions, and the parameters determining the spherically symmetrical potential inside the sphere are determined from the values of energy for the lowest energy level, calculated by statistical methods.
Abstract: The described method starts from the assumption that each valency electron in a crystal is subject to the following potential: inside the atomic sphere surrounding each atom this potential is spherically symmetrical while outside this sphere it is constant. The corresponding Schrodinger equation is solved by means of the perturbation theory with the help of certain approximate wave functions. The parameters determining the spherically symmetrical potential inside the sphere are determined from the values of energy for the lowest energy level, calculated by statistical methods.
12 citations
TL;DR: In this paper, the wave functions of valency electrons in the first Brillouin zone of both metals and how it is possible in general to construct an irreducible representation of a space group for the case that this group contains screw axes and gliding planes.
Abstract: In a few papers which will be published in the near future the two authors deal with the electron theory of metallic magnesium and aluminium and the interpretation of some of the properties of these elements or their solid solutions. This paper deals with the group analysis of the wave functions of valency electrons in the first Brillouin zone of both metals and shows how it is possible in general to construct an irreducible representation of a space group for the case that this group contains screw axes and gliding planes.
8 citations
TL;DR: In this paper, a new experimental arrangement for X-ray absorption analysis using two cylindrically bent crystals (NaCl) in a Johann focusing (fig. 1) and perpendicular incidence of the radiation on the film was described.
Abstract: The paper describes a new experimental arrangement for X-ray absorption analysis which can operate with a conventional type of sealed-off X-ray tube. It is designed to use two cylindrically bent crystals (NaCl) in a Johann focusing (fig. 1) and perpendicular incidence of the radiation on the film, by which a large aperture, improved focusing and the possibility of a considerable separation of the lines having small Δx are obtained. This enables us to replace the photographic registration by two Geiger-Muller counters placed next to each other thus fundamentally shortening the time needed for analysis. Finally an arrangement is described permitting analysis on an area smaller than 0,1 mm2; monochromatisation of X-ray radiation is achieved by filtering, registration by a GM counter.
5 citations
TL;DR: In this article, it was shown that the assumption of chemical reactions taking place on the surface of the cathode theoretically leads to an identical dependence on the temperature, and the question of dependence of the number of spurious pulses on the threshold voltage of the counter has been left open for the time being.
Abstract: Spurious random pulses were found which are independent of external radiation, depending exponentially on the voltage above the threshold of sensitivity of the counter and on the reciprocal value of the absolute temperature. It is shown that the assumption of chemical reactions taking place on the surface of the cathode theoretically leads to an identical dependence on the temperature. By calculation one can find the numerical values of the activating energies of chemical reactions or the work function of the metals of the cathode materials. The question of dependence of the number of spurious pulses on the threshold voltage of the counter has been left open for the time being.
4 citations
TL;DR: In this paper, the optical constants of metals constant in the real meaning of the word or are they dependent on the angle of incidence of the light point of the metal was investigated.
Abstract: Are optical constants of metals constant in the real meaning of the word or are they dependent on the angle of incidence? This paper is an introductory contribution to the solution of this problem.
4 citations
TL;DR: Combining two axially stigmatic image formations by refracting surfaces, this paper obtained strictly aplanatic image formation only on the following (not sufficient) conditions, i.e.,
Abstract: Combining two axially stigmatic image formations by refracting surfaces we obtain strictly aplanatic image formation only on the following (not sufficient) conditions:
4 citations
TL;DR: In this paper, the formulae deduced for the reflection of light from glass covered with multiple thin films were generalized to reflect light from a metallic mirror with many thin films.
Abstract: The formulae deduced for the reflection of light from glass covered with multiple thin films may be generalized for the reflection of light from a metallic mirror with many thin films. Thin films on the metal change (decrease or increase) the reflectance of the metallic mirror and protect it against corrosion.
3 citations
TL;DR: A prototype of a linear analyser has just been built in Prague and its principle is explained and directions for the adaptation of the tasks for this new mathematical machine are given.
Abstract: A prototype of a linear analyser has just been built in Prague. This paper will endeavour briefly to explain its principle and to give directions for the adaptation of the tasks for this new mathematical machine.
3 citations
TL;DR: A survey of all known pressure effects on the photographic emulsion, particularly the temporary desensitising effect, and briefly deals with the known fluorescent phenomena of photographic layers is given in this article.
Abstract: The paper gives a survey of all known pressure effects on the photographic emulsion, particularly the temporary desensitising effect, and briefly deals with the known fluorescent phenomena of photographic layers. Experimental results are given of research on permanent pressure desensitisation and its dependence on pressure, the wave length of the light used and the photographic material. A proof is submitted of the irreversibility of permanent pressure desensitisation. A lowering of the intensity of fluorescence of the photographic emulsion through the influence of pressure is described. All experimental results are explained on the basis of existing conceptions on the origin of the latent image as well as of fluorescent phenomena.
TL;DR: In this article, a method of successive approximation using graphical resolution of microphotometric curves formed by the merging of two diffraction lines with a known mutual ratio of intensities was described.
Abstract: The article describes a method of successive approximation using graphical resolution of microphotometric curves formed by the merging of two diffraction lines with a known mutual ratio of intensities, if it can be assumed that the “character” of both lines is the same. The method was tried out in determining the lattice constant of mixed crystals of TiC-WC.
TL;DR: In this paper, the authors used the properties of analytic functions of a complex variable to solve plane problems of the mathematical theory of elasticity rendering possible the practical solution even with more complicated boundary conditions.
Abstract: New methods have recently been applied to solve plane problems of the mathematical theory of elasticity rendering possible the practical solution even with more complicated boundary conditions. This method, worked out mainly by N. I. Muskhelishvili, uses the properties of analytic functions of a complex variable and has already made possible the solution of many practical problems. In this paper it is used for the general solution of annular regions with displacements specified on its boundaries, and a specialisation is carried out for two practical examples.
TL;DR: The paper presents a review of the contemporary state of microscope objectives with special regard to new types, the so-called reflecting micro-objectives and new methods of microscopic image formation i.
Abstract: The paper presents a review of the contemporary state of microscope objectives with special regard to new types, the so-called reflecting micro-objectives. The paper also deals with new methods of microscopic image formation i. e. the phase contrast method in ordinary and polarized light and the interference method.
TL;DR: In this paper, a survey of gravimetric work conducted during 1948 and 1949 over the basic gravimometric net-work of 1st and 2nd order on the territory of Czechoslovakia is given.
Abstract: A survey of gravimetric work conducted during 1948 and 1949 over the basic gravimetric net-work of 1st and 2nd order on the territory of Czechoslovakia is given. The choice of the gravimetric points, the way of carrying out systematic gravimetric work of basic character and measurements on the gravimetric points are described. Further the joining of the basic network to the pendulum stations, the measurement of the vertical gradient of gravity and other detailed measurements together with various checks on the Norgaard gravimeter used are also described.
TL;DR: In this paper, it is shown that the disagreement between Sahanek's relation and Kleinsteuber's derivation lies in a difference in assumptions and the contradiction between the two relations is solved.
Abstract: Sahanek has done work on electromagnetic oscillations originating in valves. In 1928 he was the first to deduce a relation for the regions of these oscillations. But others who later worked on this problem achieved results which were in contradiction to Sahanek's relation and the aim of this work is to explain this disagreement. Sahanek's derivation is given and the assumptions from which he started are pointed out in the first part of this article. In the second part Kleinsteuber's derivation is shown and the assumptions on which the calculation was based, and in the third part the contradiction between the two relations is solved. Sahanek's relation is proved by the application of Kleinsteuber's mathematical procedure to Sahanek's assumptions and it is shown that the disagreement only lies in a difference in assumptions.
TL;DR: In this paper, the Fourier synthesis with the coefficients ∥F ∥2−∥F*∥2, where ∥ F ∥ is the amplitude of the structure factor and ∥ f ∥ ∥∥ ∩ 2, is shown to obtain a map having two groups of maxima symmetrical about the origin.
Abstract: Carrying out the Fourier synthesis with the coefficients ∥F∥2−∥F*∥2, where ∥F∥ is the amplitude of the structure factor and ∥F*∥ the amplitude of the structure factor for a structure differing from the wanted one by the fact that the position of one atom is not considered, we obtain a map having two groups of maxima symmetrical about the origin. Each of these groups is arranged similarly as in the Fourier map and the corresponding maxima are displaced towards the origin in such a way that the unknown position is at the origin. If in F* the positions of a greater number of atoms are not considered, then a map is obtained which is composed of maps similar to the Fourier map with the unknown positions at the origin. If in F* a certain position is assumed incorrectly then the group of minima of the map has a similar position as the maxima of the Fourier map and is displaced, the incorrect position being at the origin. If we carry out the Fourier synthesis with the coefficients\(C = (\left| F \right|^2 - \left| {F^* } \right|^2 )\sum\limits_j {\cos 2\pi (hx_j + ky_j + lz_j ),S = (\left| F \right|^2 - \left| {F^* } \right|^2 )\sum\limits_j {sin2\pi (hx_j + ky_j + lz_j )} } \) where xjyjzj are, the positions of the atoms considered, then the unknown position can be determined from the map. It is possible to extend this method to the general case when the position of all atoms is unknown.
TL;DR: In this article, the probability of the spontaneous decay of a μ-meson into one electron and one photon and also two-neutrino annihilation with an electron in condensed matter were compared with the probability for the standard spontaneous decay into one atom and two neutrinos.
Abstract: This paper deals with the probability of the spontaneous decay of a μ-meson into one electron and one photon and also the probability of two- neutrino annihilation of the positive μ-meson with an electron in condensed matter. These probabilities are compared with the probability of the standard spontaneous decay of the μ-meson (into one electron and two neutrinos). Attention is called to the possibility of still other modes of μ-meson decay in matter.
TL;DR: In this paper, the intensity of electric and magnetic fields excited by an elementary oscillating electric dipole arbitrarily oriented in a cylindrical waveguide was derived, and the consequences of these equations were discussed.
Abstract: Equations are derived for the intensity of the electric and magnetic fields excited by an elementary oscillating electric dipole arbitrarily oriented in a cylindrical waveguide (eq. (2.11), (2.12)); the consequences of these equations are discussed.
TL;DR: In this paper, le modele "polyvitesse" adopte en deplacant, en contre partie, l'approximation sur d'autres points, parait plus satisfaisant.
Abstract: L'etude rigoureuse de fluctuations de courant dans une diode en presence d'une barriere de potentiel (potentiel minimum) se heurte a des difficultes inextricables dans le cas, ou les temps de transit des electrons cessent d'etre negligeables par rapport a la periode des fluctuations considerees, a cause surtout du fait que le faisceau electronique reel est un faisceau „polyvitesse“. L'approximation par un faisceau „univitesse“, exclusivement adoptee dans les travaux publies, n'est pas suffisante. Le modele „polyvitesse“ que nous avons adopte en deplacant, en contre partie, l'approximation sur d'autres points, parait plus satisfaisant. En effet, l'approximation principale adoptee presente cette particularite importante, qu'elle devient d'autant moins grave que la frequence s'eleve, tout en nous permettant de retrouver l'allure generale des phenomenes pour les basses frequences radio.
TL;DR: The existing method of controlling the centricity of optical systems in reflected light can be simplified by placing an auxiliary optical system having a short focal distance in front of the microscope objective.
Abstract: The existing method of controlling the centricity of optical systems in reflected light can be simplified by placing an auxiliary optical system having a short focal distance in front of the microscope objective. Reflections from all surfaces of the system under test can then be seen simultaneously in the field of the microscope and it can be recognised at first glance whether it is centric or not.
TL;DR: In this paper, a brief review of gravimetric work carried out in 1950 by the former State Institute of Geophysics (now the Central Institute of Physics) in cooperation with the State Geodetic and Cartographic Institute (SGCI) in the basic Gravimetric network of 1st and 2nd order on the territory of Czechoslovakia is given.
Abstract: The report gives a brief review of gravimetric work carried out in 1950 by the former State Institute of Geophysics (now the Central Institute of Physics) in cooperation with the State Geodetic and Cartographic Institute in the basic gravimetric network of 1st and 2nd order on the territory of Czechoslovakia.
TL;DR: In this paper, the structure of linear relativistic wave equations for particles with maximum spin 1 and non-zero rest mass was studied and it was proved that the only permissible equations for these particles are the known Dirac equations for the electron and the equations for scalar and vector (pseudo-scalar and pseudovector) meson fields.
Abstract: The paper deals with the structure of linear relativistic wave equations for particles with maximum spin 1 and with non-zero rest mass. It can be proved that the only permissible equations for these particles are the known Dirac equations for the electron and the equations for scalar and vector (pseudo-scalar and pseudovector) meson fields.
TL;DR: In this article, the n-th harmonic for longitudinal and torsional vibrations and for first and second overtone for transverse vibrations are compared according to dynamical rigidity, and the ease of excitation is compared according with dynamical strength.
Abstract: The paper deals with a method of calculating an analogue system. The calculation is carried out for the n-th harmonic for longitudinal and torsional vibrations and for first and second overtone for transverse vibrations. The ease of excitation is compared according to dynamical rigidity.
TL;DR: In this paper, the authors propose a theory ondulatoire to verify the existence of a certain nombre of plans importants at the point de vue de l'imagerie.
Abstract: En appliquant la theorie ondulatoire a l'imagerie d'un point situe sur l'axe optique, d'une part, d'un systeme stigmatique et, d'autre part, d'un systeme entache d'aberration spherique, on a calcule dans l'espace image la repartition de la lumiere le long de l'axe. Les resultats theoriques donnes par l'optique ondulatoire conduisent a prevoir les conditions favorables pour la formation d'un plus grand nombre des plans image. L'existence des differents plans image a ete examinee experimentalement, d'une part, directement par la mesure photographique du pouvoir resolvant de l'ensemble „objectif+couche photographique“ et, d'autre part, en utilisant un microscope, par la determination visuelle et photographique des positions des maxima et des minima et de la qualite des images de differents objets formees dans les plans de ces maxima et minima. On a verifie l'existence d'un certain nombre des plans importants au point de vue de l'imagerie.