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1.
The changes in domain structure as a function of the thickness of the crystal are studied on artificial magnetoplumbite crystals. The thickness dependence of the width of the domains is also studied; up to thicknesses of about 10 it follows the theoretical halfpower law. Above 10 the exponent is 0·633. The energy density of the Bloch walls=4·82 erg cm–2 and the exchange constantA=0·66×10–6 erg cm–1 are calculated on the basis of the above measurements.
We thank Z. Málek and V. Janovec for discussions and some remarks. 相似文献
. , 10 . 0,633. = =4,82 erg m–2 =0,66.10–6 erg cm–2.
We thank Z. Málek and V. Janovec for discussions and some remarks. 相似文献
2.
Antonín Rrokeš 《Czechoslovak Journal of Physics》1957,7(3):320-325
50–100 , 1–2 1–10 . - . - . , , - . -. 相似文献
3.
The new approximative method for calculating the frequencies of longitudinal vibrations of isotropic homogeneous rods described in part I. is used for rods of circular crosssection. Similarly to the rods of rectangular cross-section there does not exist any dead zone of frequencies.
II.
, I. (. . 366), . , , .相似文献
4.
5.
A. Corciovei 《Czechoslovak Journal of Physics》1960,10(12):917-926
The magnetic properties of thin ferromagnetic films are studied taking into account the magnetic anisotropy term in the Hamiltonian. In the second approximation equations are obtained for the magnetization of the monatomic layers parallel to the surface of the thin film. From these equations one obtains the Curie temperature, which depends on the thickness of the thin film and the ratio a between the anisotropy constant and the exchange energy between two neighbours. A value can be chosen for such that the thin film becomes ferromagnetic only for a thickness greater than a definite value and in this manner the theoretical results can be fitted to the experimental data. The situation in cobalt thin films is dealt with in particular.
The author extends his thanks to the research workers of CIFA 1 as well as to Dr. L. Valenta for information on the same subject. 相似文献
. , . , . , , - , . , , .
The author extends his thanks to the research workers of CIFA 1 as well as to Dr. L. Valenta for information on the same subject. 相似文献
6.
I. šantavý 《Czechoslovak Journal of Physics》1961,11(11):783-786
Zusammenfassung Im vorliegenden Artikel wird die Durchlässigkeit eines beliebigen Systems homogener oder inhomogener Schichten mit beliebiger Leitfähigkeit bei senkrechtem Einfall einer elektromagnetischen Welle untersucht. Es wird bewiesen, da\ das Verhältnis der Durch-lässigkeiten beim Auftreffen der Welle von der einen und von der anderen Seite lediglich von den Leitfähigkeiten der Medien auf beiden Seiten des Systems abhängt. Falls die Leitfähigkeiten beider Medien gleich sind, sind auch die Durchlässigkeiten in beiden Richtungen gleich.
. , . , .相似文献
7.
8.
V. Santholzer 《Czechoslovak Journal of Physics》1960,10(8):595-602
A survey is given of the results of measuring the radioactivity of rain-out from 1. 11. 1956 to 1. 2. 1960 and of fall-out from 1. 11. 1958 to 1. 2. 1960.The temporary cessation of nuclear weapon tests from 1. 11. 1958 became apparent in the second half-year after the cessation (from 1. 5 to 31. 10. 1959) by a decrease in the cumulative activity to 45% of the value for the first half-year (from 1. 11. 1958 to 30. 4. 1959). At the end of 1959 another decrease was apparent.It was shown on the basis of long-term investigation into the activity that the samples of fall-out with greater activity contain relatively very little admixture from earlier nuclear tests so that in the period of a few weeks to months the sets of fission products may be regarded as practically isolated. The exponentn in the relationA=at
–n is most frequently 1.2 for the period of the first four mounths and for older samples is most oftenn=1.5. The energy of the beta and gamma rays from fall-out was estimated on the basis of absorption measurements. It was shown that the quality of the beta radiation varies with the age of the samples.A brief survey is given of the results of determining the Sr 90 content in fall-out and milk, and of the methods of physical evidence of Sr 90 used.
The author thanks Prof. F. Bhounek, member of the Czechoslovak Academy of Sciences, for valuable advice during this work. 相似文献
1. 11. 1956 1. 2. 1960 1. 11. 1958 1. 2. 1960. 1. 11. 1958 , ( 1. 5. 31. 10. 1959) 45% ( 1. 11. 1958 30. 4. 1959). 1959 . . , , . n A=at –n 4 1,2; n=1,5. - - . , - . Sr90 . Sr90.
The author thanks Prof. F. Bhounek, member of the Czechoslovak Academy of Sciences, for valuable advice during this work. 相似文献
9.
An investigation of finite-size scaling for systems with long-range interaction: The spherical model
A method is suggested for the derivation of finite-size corrections in the thermodynamic functions of systems with pair interaction potential decaying at large distancesr asr
–d –
, whered is the space dimensionality and>0. It allows for a unified treatment of short-range (=2) and long-range (<2) interaction. The asymptotic analysis is illustrated by the mean spherical model of general geometryL
d–d×
d
subject to periodic boundary conditions. The Fisher-Privman equation of state is generalized to arbitrary real values ofd, 0d. It is shown that the-expansion may be used to study the breakdown of standard finite-size scaling at the borderline dimensionalities. 相似文献
10.
Radko Seidl 《Czechoslovak Journal of Physics》1959,9(4):517-523
.
The influence of the emission properties of an anode on the characteristics of GM counters
The hitherto unknown mechanism of the production of false pulses is investigated and its influence on the characteristics of counters is discussed.相似文献
11.
Using the Kubo-Martin-Schwinger boundary condition for equilibrium states of quantum statistical mechanics of fermion gas, we prove that forT;0 a one-particle evolution (corresponding essentially to bilinear hamiltonians) generally defines a unique equilibrium state, which is quasi-free. Conversely any quasi-free state is the equilibrium state for a single one-particle evolution if it has no Fock part in its product decomposition. Limiting cases whereT 0 andT are studied. In the case whereT 0 one shows that the state generally converges to a Fock state linked to the evolution.Attaché de Recherche au C.N.R.S.This work is a part of a Thèse de Doctorat d'Etat presented to the Faculté des Sciences de Marseille, April 23, 1969, under the number A.O. 3073. 相似文献
12.
Single crystals of BaTiO3, containing one 90° domain wall, were used to study the origin and character of the movement of such a wall in an alternating electric field having a frequency of 50 c/s. The experimental results are discussed from the phenomenological point of view.
The authors would like to thank A. Glanc for preparing the crystals for measurement, V. Dvoák, J. Kaczér and V. Janovec for fruitful discussions. 相似文献
90- BaTiO3
iO3, 90- , 50 Hz. .
The authors would like to thank A. Glanc for preparing the crystals for measurement, V. Dvoák, J. Kaczér and V. Janovec for fruitful discussions. 相似文献
13.
14.
, - - . , - , , :32P,35S 90Sr+90Y. 相似文献
15.
The paper describes a new experimentally found phenomenon of the effect of standing stratification on the parameters of moving striations in the positive column of a glow discharge.
. . M. Hobaky 相似文献
. . M. Hobaky 相似文献
16.
F. C. Hoh 《International Journal of Theoretical Physics》2000,39(4):1069-1084
An expression for the decay rate (0 ) has been derived in the frameworkof the spinor strong interaction theory, a first-principles strong interaction theoryproposed some years ago as an alternative to low-energy QCD. The startingpoint is the SO(3) gauge-invariant action for two quark mesons which has beensuccessful in accounting for confinement, + + , e+, and 0 e+, nonexistenceof the Higgs boson, and other low-energy mesonic phenomena. The quasi-four-quarkmeson equations developed for the decay of a vector meson into twopseudoscalar mesons V PP has been taken over here to apply to P(0) VV(+ –) (plus + and – which annihilate each other). This mechanismin principle agrees with that of the assumption of vector meson dominance inthe literature. It, together with the effect of form factors, arises naturally in theformalism and need not be assumed. Equations for the perturbed vector mesonwave functions cannot be simply solved and an assumption has been made toobtain an estimate of their magnitude. Together with a constant associated withthe strong coupling obtained earlier from V() PP(K+K–), the estimated decayrate is 19.2 eV, in order-of-magnitude agreement with data (7.74 eV). 相似文献
17.
18.
Otto Litzman 《Czechoslovak Journal of Physics》1957,7(6):690-700
. n : , . npou u , n . n n npocm . 相似文献
19.
Ola Bratteli Richard H. Herman Derek W. Robinson 《Communications in Mathematical Physics》1978,59(2):167-196
For automorphism groups of operator algebras we show how properties of the difference
t
– '
t
are reflected in relations between the generators , . Indeed for a von Neumann algebraM with separable predual we show that if t – 't 0.28 for smallt, then = 0(+)°-1 where is an inner automorphism ofM and is a bounded derivation ofM. If the difference
t
– '
t
=O(t) ast ; 0, then = + and if
t
– '
t
0.28 for allt then =. We prove analogous results for unitary groups on a Hilbert space andC
0,C
0
*
groups on a Banach space.This paper subsumes an earlier work of the same title which appeared as a report from Z.I.F. der Universität BielefeldWith partial support of the U.S. National Science Foundation 相似文献
20.
Vladimír Hermoch 《Czechoslovak Journal of Physics》1959,9(4):505-511
.
On processes in electrode spaces of short-time high-intensity electric discharges
The conditions and causes of the interrupted emission of the vapours of the material of short-time high-intensity electric discharge electrodes are discussed on the basis of earlier and new observations.相似文献