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71.
Ladislav Štourač 《Czechoslovak Journal of Physics》1959,9(6):717-720
, Bi2Te3-Bi2Se3. , , , . .
Influence of ageing on change in electrical properties of semiconducting systems of Bi2Te3-Bi2Se3
The paper describes the effect of ageing observed on a semiconducting system Bi2Te3 — Bi2Se3. It is shown that the change in electrical conductivity and thermoelectric force, which takes place during ageing, is caused by the change in concentration of the free electrons. The influence of this process on the efficiency of equipment employing the Peltier effect is analyzed.相似文献
72.
Ladislav Špaček 《Czechoslovak Journal of Physics》1959,9(2):186-199
The periodic domain structures on unfavourably oriented surface layers of ferromagnetic materials were studied both experimentally and theoretically. The connection between the surface structure and the crystallographic orientation of the crystals was confirmed. All the terms contributing to the total energy of the surface layer were calculated. A general solution of the potential problem is given for arbitrary periodic distribution of the charges.
. . . .相似文献
73.
74.
Ladislav Adamec 《Applications of Mathematics》2005,50(2):93-101
In the theory of autonomous perturbations of periodic solutions of ordinary differential equations the method of the Poincaré mapping has been widely used. For the analysis of properties of this mapping in the case of two-dimensional systems, a result first obtained probably by Diliberto in 1950 is sometimes used. In the paper, this result is (partially) extended to a certain class of autonomous ordinary differential equations of higher dimension.This research was supported by Grant No. 201/99/0295 of the Grant Agency of the Czech Republic.This revised version was published online in April 2005 with a corrected missing date string. 相似文献
75.
Ladislav Nebeský 《Journal of Graph Theory》1978,2(3):251-255
The following theorem is proved: Let G be a graph of even order. Assume that there exists a connected spanning subgraph F of G such that for every set U of four vertices in G, if the subgraph of F induced by U is a star, then the subgraph of G induced by U is complete. Then G has a 1-factor. The above theorem is derived from another sufficient condition for the existence of a 1-factor, which is also proved in this paper (Lemma 1). 相似文献
76.
The kinetics of dissolution of five fractions of commercial poly(vinyl chloride) in cyclohexanone was studied at temperatures from 20 to 70°C. Good agreement was observed between the experimental results and equations expressing the dependence of the induction periods and the rates of dissolution on temperature and molecular weight. It was found that the apparent activation energy for the swelling process lies in the range 9–14 kcal/mole and the apparent activation energy for the dissolution diffusion process in the range 8–12 kcal/mole. The apparent dependence of activation energies on number-average molecular weight indicates that the chain ends are more important in determining the dissolution rate than the centers of the polymer chains. 相似文献
77.
Ladislav Špaček 《Czechoslovak Journal of Physics》1957,7(6):714-721
Zusammenfassung
Auf Grund der Berechnung der Austauschenergie, der magnetostatischen und magnetoelastischen Energie und der Energie der Blochwände wird das bäumchenförmige Aussehen der oberflächlichen Abschlussbezirken an wenig gegenüber der Ebene (100)geneigten Ebenen erläutert. Aus dem Minimum der Gesamtenergie gehen dann, auch die Abmessungen dieser Bezirke in Abhängigkeit vom Neigungswinkel hervor. 相似文献
78.
79.
80.
D. L. Nagy R. Doerfler B. Molnár G. Ritter J. Waigel N. Zeman 《Hyperfine Interactions》1983,16(1-4):1051-1055
The Fe3+ fraction after the EC of57Co is usually evaluated supposing that ferric ions contribute a quadrupole doublet to Mössbauer emission spectra. It is shown that a not sufficiently fast relaxation of the electron spins may falsify the evaluated intensity even by a factor 2. Additional information can be gained from measurements performed in a large velocity span at low temperatures in high magnetic fields. 相似文献