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1.
Vlastislav Červený 《Czechoslovak Journal of Physics》1959,9(1):101-111
Zusammenfassung In der vorliegenden Arbeit werden die Kopfwellen untersucht, die beim Auffallen einer harmonischen Schall-Kugelwelle auf die Ebene Grenzfläche zwischen zwei flüssigen Medien entstehen. Vorausgesetzt wird, daß die Grenzfläche schwach ist, d. h. daß die Geschwindigkeit der Schallwellen im Medium mit der Erregungsquelle nur um weniges kleiner ist als die Geschwindigkeit der Schallwellen im Medium ohne die Quelle.
,
, . , , . . .相似文献
2.
E. Žižka 《Czechoslovak Journal of Physics》1960,10(4):327-333
. , 760 mm . .
Formation of cathode spots and current density distribution in cathode spots of short-time high-intensity electric discharge
The connection between the current density distribution in a spot and the vapour jets was found for a short-time high-intensity electric discharge by studying the structure of partial cathode traces and measuring the current density on the cathode. The variation of the current density on the spot with the current gradient was also found and the etching of the cathode surface with ionic bombardment at a pressure of 760 mm Hg was observed.相似文献
3.
Radko Seidl 《Czechoslovak Journal of Physics》1959,9(5):597-605
Zusammenfassung Es werden die zwei einfachsten Fälle der Exoelektronenemission untersucht und auf Grund dessen geeignete Verfahren zur Verarbeitung der Versuchsergebnisse vorgeschlagen.
.相似文献
4.
Nuclear emulsions were used to study the energy spectrum and forward-backward asymmetry of neutrons from the Co59(p,n) reaction forE
p
6·5 MeV. It was found that the decay of the compound nucleus makes a maximum contribution of 50% to the reaction yield. Energies of some excited states of the Ni59 nucleus were also determined.
The authors would like to thank all those who helped in this work, particularly all members of the cyclotron group of the Nuclear Research Institute of the Czechoslovak Academy of Sciences, who so willingly helped with the irradiation, and H. Koutová from the Faculty of Technical and Nuclear Physics, who carefully measured the emulsions. Our thanks are also due to R. Krejová from the Faculty of Technical and Nuclear Physics for developing the emulsions and J. Kopecký from the Nuclear Research Institute for providing the cobalt target. 相似文献
Co59(p,n) E p 6,5 MeV
- Co59(p,n) E p 6,5 MeV. , 50%. , Ni59.
The authors would like to thank all those who helped in this work, particularly all members of the cyclotron group of the Nuclear Research Institute of the Czechoslovak Academy of Sciences, who so willingly helped with the irradiation, and H. Koutová from the Faculty of Technical and Nuclear Physics, who carefully measured the emulsions. Our thanks are also due to R. Krejová from the Faculty of Technical and Nuclear Physics for developing the emulsions and J. Kopecký from the Nuclear Research Institute for providing the cobalt target. 相似文献
5.
The effects of edge plasma biasing have been recently investigated by different spectroscopic diagnostics on the CASTOR tokamak. Measurements in visible, VUV and XUV ranges complement the knowledge of processes during a biasing phase, and confirm the occurrence of several types of plasma biasing regimes — so called radiating regime, non-radiating regime, and reduced H regime. The use of edge plasma biasing to study the possibility of Electron Bernstein Wave conversion has been demonstrated. 相似文献
6.
We establish a new three-mode entangled state representation , of continuum variables, which make up a complete set. Using optical four-wave mixing and a beam splitter transform we can prepare , . Based on , a new number-difference--operational-phase uncertainty relation is established and the corresponding squeezing dynamics is discussed. 相似文献
7.
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
8.
Emil Antončík 《Czechoslovak Journal of Physics》1959,9(3):291-305
A new method is proposed for calculating the energy in certain special points of the Brillouin zone. The wave functions of valence and conduction electrons are given in the form of the linear combination of plane waves and the orthogonality condition of these functions to the wave functions of lower states is replaced by the repulsive potential. The practical application of this very simple method is illustrated on the energy spectrum of silicon in the centre of the Brillouin zone. It is proved that the results are comparable with some other methods, e. g. the orthogonalized plane-wave method.
The basic thesis of this paper, together with concrete calculation of the energy spectrum of diamond, was delivered at the Czechoslovak-Polish conference in Sopoty in November 1956.
In conclusion the autor would like to thank K. Trnková for carrying out the numerical calculations. 相似文献
. . . , , .
The basic thesis of this paper, together with concrete calculation of the energy spectrum of diamond, was delivered at the Czechoslovak-Polish conference in Sopoty in November 1956.
In conclusion the autor would like to thank K. Trnková for carrying out the numerical calculations. 相似文献
9.
Vladimír Dvořák 《Czechoslovak Journal of Physics》1959,9(6):710-716
The possibility of explaining the existence of a surface layer on BaTiO3 crystals by the presence of Schottky defects in the crystal is investigated. The magnitude of the potential difference between the surface and the interior of the crystal and the thickness of the surface layer, which at temperatures of over 400°C agrees with the measured values, are calculated for the cubic phase from a simplified ionic model.
In conclusion the author would like to thank Dr. M. Trlifaj and V. Janovec, candidates of physics and mathematics, for valuable remarks. 相似文献
BaTiO3
iO3 . , 400° .
In conclusion the author would like to thank Dr. M. Trlifaj and V. Janovec, candidates of physics and mathematics, for valuable remarks. 相似文献
10.
11.
12.
G. Benfatto C. Marchioro E. Presutti M. Pulvirenti 《Journal of statistical physics》1980,22(3):349-362
We consider an anharmonic crystal described by variablesS
x
,x
d
,S
x
, with one-body interaction ¦S
x
¦
and nearest neighbor (n.n.) two body interaction ¦S
x
–S
y
¦. We prove that, for
d
bounded, , where
is the correlation function for the free boundary condition Gibbs state in ,>0 and are suitable constants independent of and . This generalizes previous results obtained in the case.Research partially supported by Consiglio Nazionale delle Ricerche. 相似文献
13.
0,6 25 . , , . , 13,4 20,4 , , , . . , . .
A contribution to the absorption spectrum of amorphous selenium in the infra-red region
The absorption spectrum of amorphous selenium was measured in the region of 0·6 to 25 on samples of high purity and homogeneity. The absorption bands of amorphous and liquid sulphur were also measured in the same wave-length region. The measurements showed that the absorption bands 13·4 and 20·4 , appearing in the spectrum of amorphous selenium, are its intrinsic absorption bands and are not caused by impurities, as some authors think. The similarity between the infra-red spectra of selenium and sulphur is shown.相似文献
14.
G. Dorda 《Czechoslovak Journal of Physics》1960,10(11):820-829
A study was made of the influence of the relative humidity (from 0.5–90%) on the surface conductivity of bothp- andn-type germanium having differing resistivity. It was. found that the range of changes in the surface potential did not depend on the volume properties of germanium. An analysis of the experimental results shows that the surface potential has values approximately in the range from
s
=–3kT/q to
s
=+5kT/q for a change in humidity from 0.5 to 90%. Assuming that the Fermi level changes on the outer side of the oxide layer by approximately the same value as on the germaniumgermanium oxide boundary as a result of the increase and decrease of slow states, it follows that the levels of the slow centres are considerably distant from the Fermi level during the whole humidity range. It is also shown that on the first monomolecular layer of adsorbed water there is an increment of (7.5±0.8) x 1010 donor levels per cm2. This increase in levels either decreases with the number of adsorbed monomolecular layers of water and for 90% humidity has approximately the value 2×1010 cm–2 or remains almost unchanged with the number of layers, if it is assumed that for
s
=6.0kT/q the Fermi level passes through the centres of adsorbed water.
In conclusion the author thanks Dr. J. Taue for instigating this work and S. Koc, C. Sc., for remarks and the interest with which he followed the work. He also thanks A.Müller for measuring the Hall constant in the samples. 相似文献
0,5 90% p n. . , s =– 3kT/q s =+ 5kT/q 0,5 90%. , - , , . , (7,5 ±0,8). 1010 cm2. 90% . 2. 1010 cm–2 , , , s =6,0kT/q .
In conclusion the author thanks Dr. J. Taue for instigating this work and S. Koc, C. Sc., for remarks and the interest with which he followed the work. He also thanks A.Müller for measuring the Hall constant in the samples. 相似文献
15.
P. Kratochvíl 《Czechoslovak Journal of Physics》1960,10(12):927-930
The applicability of Tiller's considerations on the production of dislocations is proved. The density of dislocations appearing during impurity microsegregation increases with increasing rate of growth as a consequence of the corresponding change in the effective distribution coefficient. The real value of C at the microsegregation boundaries is at least twice as great as the average value of the concentration of impurities in the crystal in question.
. , , . C , .相似文献
16.
The first theoretical solution is given of the spinning impact of an imperfectly elastic sphere on a rigid, imperfectly rough plane. The method of solution is based on the general static theory of the impact of rough bodies, elaborated by one of the authors in 1952 [5]. The problem leads to a non-linear differential equation, which can be solved only by an approximate numerical method. The results of the theory are in good agreement with the experiments carried out in 1947 [4].
In conclusion the authors thank Dr. Vaclav Goldbach, lecturer at our department, for valuable help in making the experimental apparatus and in carrying out the difficult measurements by the method described in section 3 of this paper. Our thanks also go to O. Brha for help in the graphical solution and drawing of the figures. 相似文献
, . , 1952 . , . .
In conclusion the authors thank Dr. Vaclav Goldbach, lecturer at our department, for valuable help in making the experimental apparatus and in carrying out the difficult measurements by the method described in section 3 of this paper. Our thanks also go to O. Brha for help in the graphical solution and drawing of the figures. 相似文献
17.
L. Dunajský 《Czechoslovak Journal of Physics》1961,11(12):871-873
, .
Energy flux through thin dielectric film when total reflection is disturbed
It is shown that the energy flux through a thin dielectric film when total reflection is disturbed is brought about by the interference Poynting vector.相似文献
18.
It is shown that generic small data Robinson-Trautman space-times cannot beC
123 extended beyond the r=2m Schwarzschild-like event horizon. This implies that an observer living in such a space-time can determine by local measurements whether or not he has crossed the event-horizon of the black-hole. 相似文献
19.
The magnetic dipole interaction of the 150 keV state of177Lu in an environment of metallic ytterbium has been investigated by time-differential perturbed angular correlation experiments. The measurements were performed in an external magnetic field of 0.4 T at room temperature. Two independent measurements at different - cascades give the same Larmor precession frequency. From the weighted average the magnetic dipole moment of the 150 keV state is derived as =+5.5(3) K. From the angular correlation coefficient A22=–0.042(7) of the (139–150) keV - cascade the mixing ratio =+0.21(4) is deduced. The coefficient A22=+0.015(7) of the (1080–150) keV - cascade yields the mixing ratio =+0.08(4). 相似文献