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911.
912.
913.
914.
The first paper in this series initiated a study of Sylow theory for quasigroups and Latin squares based on orbits of the left multiplication group. The current paper is based on so‐called pseudo‐orbits, which are formed by the images of a subset under the set of left translations. The two approaches agree for groups, but differ in the general case. Subsets are described as sectional if the pseudo‐orbit that they generate actually partitions the quasigroup. Sectional subsets are especially well behaved in the newly identified class of conflatable quasigroups, which provides a unified treatment of Moufang, Bol, and conjugacy closure properties. Relationships between sectional and Lagrangean properties of subquasigroups are established. Structural implications of sectional properties in loops are investigated, and divisors of the order of a finite quasigroup are classified according to the behavior of sectional subsets and pseudo‐orbits. An upper bound is given on the size of a pseudo‐orbit. Various interactions of the Sylow theory with design theory are discussed. In particular, it is shown how Sylow theory yields readily computable isomorphism invariants with the resolving power to distinguish each of the 80 Steiner triple systems of order 15. 相似文献
915.
By using electrospray ionisation mass spectrometry, it was proven experimentally that the cesium cation (Cs+) forms with [2.2.2]paracyclophane (C24H24) the cationic complex [Cs(C24H24)]+. Further, applying quantum chemical calculations, the most probable structure of the [Cs(C24H24)]+ complex was derived. In the resulting complex with a symmetry very close to C3, the ‘central’ cation Cs+, fully located in the cavity of the parent [2.2.2]paracyclophane ligand, is bound to all three benzene rings of [2.2.2]paracyclophane via cation–π interaction. Finally, the interaction energy, E(int), of the considered cation–π complex [Cs(C24H24)]+ was found to be ?73.2 kJ/mol, confirming the formation of this fascinating complex species as well. This means that [2.2.2]paracyclophane can be considered as a receptor for the Cs+ cation in the gas phase. 相似文献
916.
Luk Fojt Petr Klapetek Ludk Strak Vladimír Vetterl 《Micron (Oxford, England : 1993)》2009,40(8):918-922
Atomic force microscopy was used to distinguish changes in morphology of bacteria induced by 50 Hz 10 mT magnetic field exposure. It is known that alternating magnetic field exposure causes decrease of viability of different bacterial strains. Previously we found that the viability of rod-like bacteria exposed to magnetic field decreased twice more in comparison with the spherical ones. Motivated by this fact we carried out this study with bacterial cells of both shapes. We used Escherichia coli (rod-like) and Paracoccus denitrificans (spherical) bacteria. As a result we have not observed any change in bacterial morphology neither of rod-like nor of spherical bacteria after 1 h, 50 Hz and 10 mT magnetic field exposure. 相似文献
917.
Currently there are two proposed ansätze for NSR superstring measures: the Grushevsky ansatz and the OPSMY ansatz, which for genera g?4 are known to coincide. However, neither the Grushevsky nor the OPSMY ansatz leads to a vanishing two-point function in genus four, which can be constructed from the genus five expressions for the respective ansätze. This is inconsistent with the known properties of superstring amplitudes. 相似文献
918.
919.
Petr Řepa Ladislav Peksa Tomáš Gronych Radek Ulman Jan Wild Oldřich Schneeweiss 《Czechoslovak Journal of Physics》2006,56(12):1389-1399
This article describes a measuring system that was proposed so as to enable measurement of the content of dissolved gas in
samples, whose shape is determined by the specific requirements of the simultaneous measurements and cannot be modified to
satisfy the requirements on solubility measurements. The apparatus — a dynamic UHV vacuum system — consists of a measuring
chamber fitted with a heater based on electron bombardment, which permits a change in the sample temperature according to
the selected schedule. The design of the heater permits reduction of additional heating in the actual measuring chamber, so
that the increase in pressure caused by the action of the heater can be neglected. The measuring part of the system permits
recording of changes in the overall pressure and partial pressures of selected gases in the measuring chamber. The lowest
detectable amount of dissolved gas is less than 10−5 Pa m3.
The results of measurement of the solubility of hydrogen in Ti and Fe aluminides in samples that are simultaneously used to
measure the electrical conductivity are given as an example of the suitability of the apparatus for such measurements.
This work is a part of research plan MSM 0021620834 financed by the Ministry of Education, Youth and Sports of the Czech Republic. 相似文献
920.
J. Kadeřávek J. Kozempel M. Štícha J. Petrášek M. Jirsa P. Taimr L. Lešetický 《Czechoslovak Journal of Physics》2006,56(1):D711-D717
Two retinol derivatives, 4-[(131I)-4-iodobenzoyloxy]retinol propionate and 4-[(131I)-3-iodobenzylcarbamoyl]retinol propionate, were synthesized and their biodistribution in rats was studied in vivo by the whole body scintigraphy. 相似文献