Work-hardening of Fe,Fe-0·5 wt% Si and Fe-0·9 wt% Si single crystals

Work-hardening curves of single crystals of iron and its alloys with 0·5 and 0·9 wt.% Si and paths of the tensile axis of specimens during deformation were investigated. Single crystals oriented for single glide were deformed in tension at temperatures 113, 201, 295 and 403 K at a nominal strain rate of 5·5×10^?5 sec^?1. It appears that with increasing silicon content (a) the transition between the high-temperature regime of plastic deformation (characterized by three-stage work-hardening) and the low-temperature regime is shifted to lower temperatures, (b) stage I-hardening is enhanced and (c) the flow stress level increases. These observations are explained by strong solution hardening of iron by silicon atoms which suppresses the differences between mobilities of screw and non-screw dislocations, increases the flow stress level and consequently the density of primary dislocations. As a result of this the latent hardening in the secondary slip system increases and stage I extends to a large strain.     

Temperature dependence of development of slip bands and of strain hardening in AgCl crystals

The dependence of the flow stress and the slip band density on the plastic strain has been measured at 201 K, 293 K and 363 K. The growth of deformation concentrated in an average slip band has been stated. The types of obstacles acting against the rise and development of a slip band and the temperature dependence of the strain hardening in AgCl crystals are discussed. An equation stating the dependence of the flow stress on the slip band density is presented. The hardening in AgCl crystals is classified as the stage III — hardening.     

Effect of water of crystallization on magnetic properties of MgSO4

The object of this paper has been to determine the effect of water of crystallization on magnetic properties of MgSO₄. Changes in the magnetic properties of MgSO₄ in depenedence on the number of waters of crystallization have been established from the magnetic susceptibility changes. The value obtained by measurement differs from that calculated by the additivity law. This disagreement can be explained by the presence of the thermally independent Van Vleck's polarization paramagnetism _p .The paper brings forward calculations of _p values for the individual hydrates of MgSO₄.i H₂O fori=0, 1, ..., 7. Besides, it examines what portion of the polarization paramagnetism _pi of the overall values of _pci is due to the effect of water of crystallization. On the basis of this information the deviation from the spherical symmetry, caused by hydration of the MgSO₄ molecule, has been interpreted.     

The conceptual analysis (CA) method in theories of microchannels: Application to quantum theory. Part III. Idealizations. Hilbert space representation

We illustrate the application of the conceptual analysis (CA) method outlined in Part I by the example of quantum mechanics. In the present part the Hilbert space structure of conventional quantum mechanics is deduced as a consequence of postulates specifying further idealized concepts. A critical discussion of the idealizations of quantum mechanics is proposed. Quantum mechanics is characterized as a “statistically complete” theory and a simple and elegant formal recipe for the construction of the fundamental mathematical apparatus of quantum mechanics is formulated. Our analysis may also lead to a criticism of quantum mechanics as a “strongly idealized” theory. A critical analysis of the fundamental structure of quantum mechanics seems an indispensable and natural starting point for the construction of new theories. A major technical problem in a more general application of the CA method is the lack of mathematical representation theorems for more general algebraic structures.     

A wave-packet formulation of multiparticle production at high energies

Starting from a free boson gas in a box, we formulate a statistical approach to multi-particle production. The specific feature of the small box quantization is the fact that one-particle wave functions are wave packets instead of plane waves. In this context we investigate the jet model with Bose-Einstein (BE) statistics. The transverse cut-off function is naturally related to the size of the box (production region). We compare our results with experimental data.     

On the theories of the interacting perturbations of the Reissner-Nordström black hole

A complete account of the Hamiltonian approach to the coupled perturbations of the Reissner-Nordström black hole, initiated by Moncrief, is given. All Hamiltonian equations are expressed explicitly in suitable forms; the metric and electromagnetic field perturbations are found in terms of Moncrief's gauge invariant canonical variables in the Regge-Wheeler gauge. The basic (both tetrad and coordinate) gauge invariant scalars occurring in the perturbation studies based on the Newman-Penrose formalism are then related to Moncrief's variables. The strikingly simple relations obtained enable us to show that the fundamental pair of decoupled equations, derived recently within the Newman-Penrose formalism by Chandrasekhar, can be cast into gauge invariant form, and that it can be obtained from Moncrief's formalism.It is demonstrated how the fundamental equations, supplemented by another combination of the Newman — Penrose equations, generalize the Bardeen-Press equations for uncoupled electromagnetic and gravitational perturbations of the Schwarzschild black hole.The odd and the even parityl=1 perturbations are also considered in detail. In the Appendix the relations to Zerilli's work on coupled perturbations of the Reissner-Nordström black hole are given.     

Elektrophorese der halogenokomplexe von hg(ii), bi(iii), cd(ii), pb(ii) und cu(ii) : Chloro-, bromo- und jodokomplexe in kcl,hcl,kbr,hbr und kj

The electrophoretic mobilities of chloro-, bromo- and iodo-complexes of Hg, Bi, Cd, Pb, and Cu, obtained by heavy current electrophoresis on filter paper, are presented in diagrams as a function of the logarithm of the concentrations of the halogen ions KC1, HCl, KUr, HBr and KJ, mainly in concentrations between 0.1N and 4N, were selected as complexing agents Straight lines were obtuned with characteristic slopes, breaks and parallelisms. Furthermore it can be seen from the diagiarns, that the tendency to form complexes increases on the one hand in the sequence chloro - bromo -iodo, and on the other for the chloro- and bromo-complexes in the sequence Cu - Pb - Cd - Bi -Hg In the case of the lodo-complexes the sequence is (Pb + Cd) - Hg - Cu.Figures that show the electrophoretie scpartion of a mixture of Hg - Bi - Cd - Pb - Cu in Voirious concentrations of KC1, KBr and HBr, are given. The separation of these metals in the form of halogeno-complexes can be most satisfactorily accomplished in 0.5_N KBr or 0.5NHBr.     

Rapid graphical determination of the radial intensity distribution of the small-angle scattering of X-rays from the measured data

The radially symmetrical small-angle scattering pattern (which would be obtained by the use of a direct beam having a point-like cross section) is in practice distorted, especially by the beam height. To eliminate this distortion the integration of a set of curves based on the derivative of the measured intensity distribution is required to derive the true radial intensity distribution. A rapid graphical method of plotting these curves is described and its accuracy is proved on an example. It is further shown that the radial intensity distribution can be determined in principle using the values of the measured curve instead of its derivative.

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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.