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1.
The self-regulation of an inert gas shielded metal welding arc is dealt with briefly. A thermodynamic equation is derived for the self-regulation of such an arc.
. .
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2.
The basic equations of the dynamics of the continuous distribution of dislocations analogical to Maxwell equations are derived in a series of papers [I, II, III]. The analogy of the elastic and electromagnetic fields is analyzed. In part [III] some special problems are discussed, such as the density of the forces acting on the dislocations, the energy dissipation during the movement of dislocations, which is expressed by an equation analogical to Ohm's law. The equations derived in the previous parts in four-dimensional symbolics are considered in the three-dimensional differential and integral form. It is found that in special cases the relations become the known ones of elastodynamics, hydrodynamics and the static theory of the continuous distribution of dislocations. It is found that Kröner's method of integrating the equations of the dislocation field by means of so-called incompatibility tensors is analogical to the integration of the Maxwell equations by means of Hertz vectors. The analogy between the elastic dislocation field and the electromagnetic field is discussed in detail.
III.
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3.
The paper contains further results of studying dislocations rendered visible by anodic dissolving on the surface of single crystals of alpha-iron. The influence of the crystallographic orientation of the surface is investigated, the effect of carbon is confirmed and the anodic process is studied. The mechanism of dissolving of the crystal is given and a new more suitable method of rendering dislocations visible is derived.
, . , . , .


The author thanks F. Kroupa and J. Hejduk for critical remarks and discussion.  相似文献   

4.
The Bardeen-Shockley formula for the mobility of an electron or hole in a homopolar semi-conductor is derived in a different way to that in which its authors obtained it. The interaction energy of the electron with the acoustic lattice oscillations is derived in an original way. A new possibility for determining the energy gap is given.
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- , , , . . .
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5.
A new theory of rectangular coils without an iron core is described which amends the old one of Fabry and Bitter. It enables us to compute field intensities in coils having very small openings, which the old theory could not do.
, , , .
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6.
The effect of the orientation of zinc single crystals and the rate of growth on the direction of the formation of cellular substructure is observed. A model accounting for the observed dependences is proposed.
. .
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7.
Zusammenfassung An Einkristallen von Zn mit Beimengungen von Cd oder Cu wurde experimentell die Abhä agigkeit der Größe des Durchmessers der Fasersubstruktur vom Gehalt der Beimengungen untersucht, die aus der Theorie von Rutter und Chalmers [1] hervorgeht. Es wird die Möglichkeit gezeigt, die Größe des Verteilungskoeffizientenk aus den erzielten Ergebnissen abzuschätzen.
, . , k.
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8.
The above problem is met, for example, in the case of the collision of molecules of the atmosphere with an artificial earth satellite and leads to the problem of determining the probability distribution of the absolute value of the vector sum of a constant vector and a Maxwell vector (the latter being a vector, whose rectangular components are distributed normally, with the same standard deviation and mean value zero). The resultant probability density is given by equation (18), the complement to the distribution function by (24), the mean value by (27) and the variance by (31). These results are obtained by transforming the corresponding three-dimensional normal distribution to spherical co-ordinates and integrating over the co-ordinate angles and , which yields the required probability density; the other results are then obtained from it by the usual methods.
, , (. . , ). (18), -(24), -(27) (31). , ; .
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9.
On the basis of the boundary conditions of the electromagnetic theory an explicit calculation of the absorption in a thin metallic film was carried out with the result that transport and interference components were found to exist. By applying the method to a simple metal-dielectric boundary the physical interpretation was given of the energy balance, which had hitherto been regarded as unclear. It was also explained why the reversibility principle fails when applied to a metal-dielectric boundary.
, . - , . , - .
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10.
We have found that gamma-irradiated polyformaldehyde does not exhibit the effect of the disappearance of the hyperfine structure of EPR spectrum as a function of the dose or the time passed since the end of irradiation, as was found earlier for a group of polymers having only C-C-C-C-atoms in the polymer chain. This difference in the change in the EPR of the polyformaldehyde (PFA) spectrum compared with the polymers with a -C-C-C-C- chain is explained by the impossibility of forming a conjugate double bond in the -C-O-C-O- chain in PFA.
, , -, , , atom C-C-C-C-. ( ) C-C-C-C- , C-O-C-O- qu .


The author thanks K. Vacek for many valuable discussions which helped this work.  相似文献   

11.
In paper [1] Fang derived an expression for the complex conductivity of plasma assuming that the distribution function of the electrons is Maxwellian and the collision frequency is directly proportional to their velocity. Since the assumptions are approximately satisfied in the positive column of a d-c glow discharge in Ne, the applicability of Fang's relation is investigated for this case.
[1] , . , .
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12.
A detailed analysis of the dependence of the surface recombination velocitys on the surface potential s leads to the conclusion that the position of the surface recombination level with respect to the centre of the energy gapE t -E i does not coincide with the valueq s *, while the surface recombination velocitys decreases to half its maximum value. The difference between the two quantities is negligible only when the width of the curves( s ) between the points corresponding to the valuess=1/2s max is greater than 8kT.
s s , E t -E i s , s . , s( s ) , s=1/2s max, 8kT.
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13.
The paramagnetic spectrum of the Fe3+ ion in a CdWO4 monocrystal was measured on a frequency of 9600 kMHz at 290°K. The spin-Hamiltonian of the Fe3+ ion was determined and had the form of (1). The constants derived for the spin-Hamiltonian areE/D=0·144±0·002,D=23·8 kMHz.
Fe3+ CdWO4
Fe3+ CdWO4 9600 kMHz 290°K. - Fe3+ (1), E/D 0,144±0,002 D 23,8 kMHz.


In conclusion, the authors thank . Bárta and V. Kment from the Society for Chemical and Metallurgical Production in Ústí n/L for producing and supplying the monocrystals and for much valuable advice.  相似文献   

14.
Zusammenfassung In der vorliegenden Arbeit werden einige Ergebnisse, die an ferromagnetischen Proben erhalten wurden, beschrieben. Verwendet wurde Kupferdraht, auf welchen Nickelschichten von verschiedener Dicke niedergeschlagen wurden. Die Proben zeigen, daß dabei die innere Reibung im magnetischen Wechselfeld unter den Wert, der der magnetischen Sättigung entspricht, fallen kann, und daß am Torsionspendel unter bestimmten Umständen erzwungene Schwingungen entstehen.
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15.
16.
The influence of the magnetic after-effect on the rectangularity of the hysteresis loop of MgMn ferrites in two different compositions was studied; it was found that this influence is so small that it cannot be the actual cause of a rectangular hysteresis loop of such materials.
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- . , , .
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17.
The basic equations of the dynamics of the continuous distribution of dislocations analogical to Maxwell's equations are derived in a series of papers I, II, III. The analogy of the elastic and electromagnetic fields is analyzed. In part I the basic equations of the continuous distribution of dislocations are derived for the dynamic case (especially for small deformations and for the Poisson ratio equal to zero in a continuum, infinite with respect to space and time, from the variational problem by means of the formal apparatus of the special theory of relativity.
I.
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18.
It is shown for a one-dimensional approximation that, around a disturbance in the ion concentrationn +(x, t) in the axial direction of a cylindrical plasma, a corresponding electron distributionn (x, t) is established with such a large velocity that under the usual conditions of a discharge plasma this electron distribution follows the relatively slow changes in ion concentration practically without delay. Relation (24) then holds for the electron concentration, the parametersl 1,l D being given by Eqs. (15) and (16). As long as the disturbance of the ions isn +(x) 0, a space chargeq 0(n +-n) is produced and maintained in the plasma even if the disturbance of the equilibrium state of the plasma in the initial stage was electrically neutral (i.e.n +(x, t=0)==n (x,t=0)). The dimensions of these space charges can be many orders larger than the Debye characteristic lengthl D ; this is shown on an example of a spatially periodic curven +(x). The unique (quasi-stationary) expression of the electron concentrationn by means of the deflection of the ion concentrationn +(x, t) permits a considerable simplification of the solution of the problems connected with axially disturbing the homogeneous state of a plasma, sincen (x, t) can be eliminated from the equations of continuity of the plasma by substituting from (24), and the problem becomes that of determining the curve of the ion concentrationn + from the equations modified in this way.
, +(, t) - (, t) , . (24), l 1 l D (15) (16). +() 0, q 0(n+ — n), , (..n +(x,0)=(, 0)). () +(, t) , , . . (, t) n + .
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19.
The effect of an excess of oxygen on the electric conductivity of a pre-illuminated and heated single crystal of Cu2O is investigated. It is found that the influence of illumination on the electric conductivity, together with the concentration of impurities, increases with increasing oxygen pressure during annealing.
, Cu2O. , .


In conclusion the author thanks E. Klier and J. Pastrak for valuable remarks and discussion.  相似文献   

20.
The method of sliding photomultipliers was used to study the connection between two forms of the positive column in oxygen — the so-called low-gradientT-form and the highgradientH-form — and the presence of moving striations in the positive column. It was shown that in theT-form of a positive column striations are always present which move from the cathode to anode with a velocity of several thousand metres/sec. The highgradient form of theH-positive column, on the other hand, is not striated. The non-single-valuedness of the value of the longitudinal electric field in a discharge in oxygen is thus explained by the presence or absence of phenomena of a time variable character.
— - H - — . , - , /. , , . , , , .
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