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981.
Aleksander A. Kubicki Piotr Bojarski Marek Grinberg Micha? Sadownik Benedykt Kukliński 《Optics Communications》2006,263(2):275-280
Apparatus to study time-evolution of emission spectra over very wide time and spectral range is described. Excitation part of the equipment consists of solid state Nd:YAG laser and optical parametric generator. The heart of the detection system consists of spectrograph and streak camera. The significance of optics and electronics built in the system for proper, fast and convenient measurements is underlined. The results of donor-acceptor energy transfer in a rigid polyvinyl alcohol matrix serve here as an example of application our equipment to study complex systems. 相似文献
982.
T. Ossowski D. Zarzeczańska L. Zalewski P. Niedzia?kowski R. Majewski A. Szymańska 《Tetrahedron letters》2005,46(10):1735-1738
The synthesis of a lysine-like chromo-ionophore and its derivatives, useful in peptide chemistry, is described. The influence of the peptide framework on the anthraquinone properties is examined with spectroscopic and electrochemical methods. 相似文献
983.
984.
A. Shengelaya H. Drulis B. Macalik M. Suszyńska 《Zeitschrift für Physik B Condensed Matter》1997,101(3):373-376
Paramagnetic resonance of Bridgman-grown NaCl crystals nominally doped with divalent nickel was studied over the temperature range from 4 K to 300 K. The broad isotropic EPR line with g = 2.12 ÷ 2.23 and ΔH pp = 280 ÷ 780 G was detected at temperatures higher than 130 K for samples of various thermal history. The origin of these spectra was attributed to aggregated and precipitated Ni2+ ions. At temperatures lower than 40 K another ESR signal was registered. It was an anisotropic one, the intensity of which strongly depends upon the temperature. This spectrum results from substitutional Ni+ ions with tetragonally distorted surrounding along a S100T direction. The angular dependence of the ESR line positions was fitted to an appropriate spin-Hamiltonian with the g-factor components g ∥ and g ⊥ equal to 2.86 and 2.10, respectively. The temperature-dependence of the signal intensity at temperatures between 4 and 110 K has been interpreted in terms of a transition from the static to dynamic Jahn-Teller effect. 相似文献
985.
Piotr Krzyanowski 《Mathematical Methods in the Applied Sciences》1994,17(11):837-854
We prove existence and uniqueness theorems for weak solutions of equations describing stationary isothermic motion of a mixture of two viscous incompressible fluids with asymmetric stress tensor, in a bounded subset of ?3. The model of the flow we consider here assumes that some of coefficients characterizing isotropic properties of the fluid equal zero. 相似文献
986.
Andrzej Wolkenberg Tomasz Przes?awski Kazimierz Regiński 《Journal of Physics and Chemistry of Solids》2003,64(1):7-14
At low temperatures In0.53Ga0.47As samples show an increase of carrier concentration, which can be explained in terms of a two carriers transport model. This type of problem exists since the beginning of the semiconductor era, dating back to monocrystalline germanium.We propose that in all the investigated layers, there are X atoms or charged dislocations in the region of the first monolayers, which are built in during epitaxial growth. The layers were intentionally undoped. They form an impurity band in which low mobility carriers dominate over the localised electron scattering due to the s-d exchange interaction. These carriers do not freeze out at liquid helium temperature and give rise to two transport media for electrons; a conduction band at higher temperatures and an impurity band at lower temperatures. The electron which fall down onto the previously ionised X atoms, then move by thermally activated hopping. We show that the two carriers model for In0.53Ga0.47As epitaxial layers are confirmed by the carrier concentration-temperature, carrier concentration-magnetic field, resistivity-magnetic field behaviour, and also by YKA theory also. The differences between the two transport models are so distinctive that observed phenomena may exist. This paper presents experimental results, which constitute comprehensive evidence for the complicated structure of the semiconductor epitaxial layers on the sample of n-type In0.53Ga0.47As/InP layer with n=2.2×1015/cm3. 相似文献
987.
Stanisław Wroński 《Mathematica Slovaca》2007,57(4):359-368
In [ANISZCZYK, B.-FRANKIEWICZ, R.: Non homeomorphic density topologies, Bull. Polish Acad. Sci. Math. 34 (1986), 211–213] the authors constructed 2c non-homeomorphic density topologies tied to the concept of measure. In [WROŃSKI, S.: The number of non-homeomorphic I-density topologies. Institute of Mathematics of Polish Academy of Sciences. Preprint 482, December 1990, XXXIV Semester in Banach Center, Theory
of Real Functions] an analogous construction has been given for topologies tied to the concept of category. Here we present
a generalization containing both the results mentioned above. This generalization based only on the topological ideas is independent
of the concept of measure or category.
Communicated by L’ubica Holá 相似文献
988.
This paper explores the connection between homeomorphisms of the unit circle, codimension-1 measured laminations on closed surfaces, and free actions of surface groups on IR-trees. 相似文献
989.
Piotr Bogus?aw Mucha Wojciech M. Zaj?czkowski 《Journal of Differential Equations》2002,186(2):377-393
In this paper a special Lp-estimate for the linearized compressible Navier-Stokes in the Lagrangian coordinates for the Dirichlet boundary conditions is obtained. The constant in the estimate does not depend on the length of time interval [0,T]. The result is essential to obtain an existence for regular solutions for the nonlinear problem with the lowest class of regularity in Lp-spaces. 相似文献
990.
Jerzy Kociński 《International Journal of Theoretical Physics》2002,41(2):231-250
The Cayley–Klein parameters for the de Sitter groups SO(4, 1) and SO(3, 2) are introduced, and in an extension of the earlier investigation of quasigroups connected with Clifford groups, quasigroups connected with the SO(4, 1) and SO(3, 2) groups are determined. It is shown that these quasigroups have eight-dimensional, double-valued irreducible cracovian representations. The covariance of a five-dimensional form of the Dirac equation with respect to the quasi-rotations forming quasigroups connected with the groups SO(4, 1) and SO(3, 2) is demonstrated. An analogy is drawn between Weyl's hidden symmetry group and a quasigroup. 相似文献