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1.
E. Antončík 《Czechoslovak Journal of Physics》1960,10(1):22-27
An approximate method, analogical to the orthogonalized plane-wave method, is used to calculate the energy at a number of points in the Brillouin zone of lithium and the results are compared with the energy values calculated by the OPW method. Some of the general properties of the matrix elements of the repulsive potential are discussed and correlation with other methods carried out.
In conclusion the author thanks Dr. Glasser for communicating the numerical values of the wave function and K. Trnková for carrying out the numerical calculations. 相似文献
, , , . .
In conclusion the author thanks Dr. Glasser for communicating the numerical values of the wave function and K. Trnková for carrying out the numerical calculations. 相似文献
2.
E. F. Holländer 《Czechoslovak Journal of Physics》1962,12(1):35-47
Recent advances in the continuum theory of dislocations have been achieved mainly in two directions: (1) the differential geometric (non-linear) theory of stationary dislocations, and (2) the formal linear dislocation dynamics. These two are unified here to form a differential geometric dynamical theory of continuous distributions of dislocations. To begin with, the basic concepts of the geometric theory are briefly summed up. The fundamental geometric equation of time-dependent distortions is derived first in a physically instructive elementary way and afterwards by means of exact differential geometry. A symmetrized form of the equation is given in terms of deformations or the metric tensor. The physical meaning of a previously introduced dislocation current tensor is discussed. A general form of the continuity equation for the dislocation current is then given. Thereafter the forces acting on dislocations are dealt with in connection with energy dissipation during plastic deformation and Ohm's law for dislocations, which has been introduced recently. The dislocation conductivity in simple cubic crystals is discussed. Finally, an invariant partition of the torsion (or dislocation) tensor is introduced. The semi-symmetrical part of this tensor corresponds to volume deformations, while the remainder is associated with shape deformations only. The main unsolved problems are enumerated, and some concluding remarks, concerned with the correspondence between dislocation theory on the one hand and general relativity and differential geometry on the other, are added.
, , : (1) - ( ) (2) . . . , . , . . . , , . . ( ). , . , , , .相似文献
3.
Measurement of the circular polarization of gamma-quanta emitted from the nuclei after the capture of polarized thermal neutrons
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, -. 相似文献
4.
. 1', . . . 相似文献
5.
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
6.
B. Rothenstein 《Czechoslovak Journal of Physics》1959,9(3):410-411
7.
A. Vaško 《Czechoslovak Journal of Physics》1962,12(9):670-684
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The theory and structure of the temperature image
The paper describes the theory of the formation of a temperature image when there are large temperature differences and introduces the concept of temperature distortion of an image. It also deals with the geometrical distortion of the temperature image by the longitudinal thermal conductivity of the receiver layer and gives a solution of the corresponding differential equation of the temperature image for the case of a general linear line test and general circular concentric test. Equations are derived for the temperature distributions of the temperature images of some optical lineated and circular test objects and their geometrical distortion due to the thermal conductivity of the receiver layer is investigated.相似文献
8.
J. Čermák 《Czechoslovak Journal of Physics》1961,11(9):652-659
The neutron density in the vicinity of a black cylindrical rod partly inserted in a bare reactor is calculated and illustrated by a numerical example. The starting point is a two-group diffusion theory approximation. While the dependence of the effect of the rod on the insertion depth can be calculated simply by means of perturbation theory, the question of the neutron density estimate in the vicinity of the rod is considerably more difficult and in some considerations the estimate of the neutron density caused by the presence of the rod is indispensable. The method makes it possible to determine the reactivity value of the rod in dependence on the insertion depth and especially the neutron density deformation in the vicinity of the rod.
In conclusion the author thanks J. Svato for help in carrying out the numerical calculations. 相似文献
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. , . , , . , . [1] . .
In conclusion the author thanks J. Svato for help in carrying out the numerical calculations. 相似文献
9.
10.
Miloš Novák 《Czechoslovak Journal of Physics》1959,9(1):78-83
[1] t
B
, t
B
. , t
B
, . .
A note on the theory of the successive production of moving striations in the plasma of inert gases
Approximate expressions are derived on the basis of Pekárek's theoretical paper [1] for the period of the maximum tB of a wave packet produced by the passage of a wave of stratification before the aperture of a photomultiplier, and for its time width in the half-height tB. The relaxation time of a wave of stratification, following from the theory [1], can thus be calculated by means of the experimentally measured velocity of motion of the maximum of a wave packet u and its width tB. The calculation is supplemented by numerical data on the magnitude of errors committed by using approximate expressions.相似文献
11.
Ira W. Herbst 《Communications in Mathematical Physics》1980,75(3):197-205
LetH=–+V+Fx
1 withV(x
1,x
) analytic in the first variable andV(x
1+ia, x
) bounded and decreasing to zero asx for eacha . Let be an eigenvector of –+V with negative eigenvalue. Among our results we show that forF0, (,e
–H
) decays exponentially at a rate governed by the positions of the resonances ofH. This exponential decay is in marked contrast to conventional atomic resonances for which power law decay is the rule.Research supported by NSF Grant No. MCS 78-00101. 相似文献
12.
Ning Jin Yang Guo Zhuoli Zhang Longjiang Zhang Guangming Lu Andrew C. Larson 《Magnetic resonance imaging》2013
Purpose
To investigate the feasibility of combining GESFIDE with PROPELLER sampling approaches for simultaneous abdominal R2 and R2* mapping.Materials and Methods
R2 and R2* measurements were performed in 9 healthy volunteers and phantoms using the GESFIDE-PROPELLER and the conventional Cartesian-sampling GESFIDE approaches.Results
Images acquired with the GESFIDE-PROPELLER sequence effectively mitigated the respiratory motion artifacts, which were clearly evident in the images acquired using the conventional GESFIDE approach. There was no significant difference between GESFIDE-PROPELLER and reference MGRE R2* measurements (p = 0.162) whereas the Cartesian-sampling based GESFIDE methods significantly overestimated R2* values compared to MGRE measurements (p < 0.001).Conclusion
The GESFIDE-PROPELLER sequence provided high quality images and accurate abdominal R2 and R2* maps while avoiding the motion artifacts common to the conventional Cartesian-sampling GESFIDE approaches. 相似文献13.
14.
, , , , . 相似文献
15.
Using a recent result of Sinai, we prove that the almost Mathieu operators acting onl
2(), (l
Y,
)(n) = (l+1)+(l–)+ cos(n+) (n) have a purely absolutely continuous spectrum for almost all a provided that is a good irrational and is sufficiently small. Furthermore, the generalized eigen-functions are quasiperiodic. 相似文献
16.
Background
Global cerebral ischemia triggers neurodegeneration in the hippocampal CA1 region, but the mechanism of neuronal death remains elusive. The epsilon isoform of protein kinase C (PKCε) has recently been identified as a master switch that controls the nucleocytoplasmic trafficking of ATF2 and the survival of melanoma cells. It is of interest to assess the role of PKCε–ATF2 signaling in neurodegeneration.Results
Phosphorylation of ATF2 at Thr-52 was reduced in the hippocampus of PKCε null mice, suggesting that ATF2 is a phosphorylation substrate of PKCε. PKCε protein concentrations were significantly reduced 4, 24, 48 and 72 h after transient global cerebral ischemia, resulting in translocation of nuclear ATF2 to the mitochondria. Degenerating neurons staining positively with Fluoro-Jade C exhibited cytoplasmic ATF2.Conclusions
Our results support the hypothesis that PKCε regulates phosphorylation and nuclear sequestration of ATF2 in hippocampal neurons during ischemia-induced neurodegeneration.17.
H. V. Klapdor-Kleingrothaus A. Dietz I. V. Krivosheina 《Foundations of Physics》2002,32(11):1803-1803
Corrigendum
Corrigenda 相似文献18.
Li-yeng Sung 《Mathematical Physics, Analysis and Geometry》1999,2(4):417-418
Volume Contents
Contents of Volume 2 相似文献19.
Editorial
Editorial 相似文献20.
J. Gasser 《The European Physical Journal A - Hadrons and Nuclei》2003,18(4):711-711