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901.
J. Balogh D. Kaptás L. F. Kiss T. Kemény L. Bujdosó I. Vincze 《Hyperfine Interactions》2006,169(1-3):1343-1347
Magnetic multilayers of 57Fe with nominal thickness, T
nom, between 0.4 and 1.0 nm separated by 3.0 nm Al spacer layers were prepared by alternate deposition of the constituents in
high vacuum. The samples were investigated at 4.2 K in external magnetic field. A fraction of Fe atoms corresponding to about
0.3 nm equivalent Fe-thickness was found to mix into the Al spacer. The extremely strong magnetic anisotropy observed for
T
nom < 0.8 nm is attributed to Fe layers of approximately two atomic planes thick. The anisotropy decreases considerably after
the building up of the third Fe atomic layer starts at T
nom = 0.8 nm, but full saturation was not achieved even for T
nom = 1 nm and 3 T magnetic field applied perpendicularly to the sample plane. 相似文献
902.
The first twelve members of three new mesogenic homologous series have been characterized, each of which are composed of molecules possessing lateral alkyl chains. The n-alkyl 2,5-bis-(4-n-hexyloxy-benzoyloxy)-benzoates are purely nematic whereas both nematic and smectic behaviour is observed for the 4-cyano-4'-biphenylyl 3'-n-alkyloxybenzoates and the 4-cyano-4'-biphenylyl 3',4'-n-alkyloxybenzoates. The transitional properties of these series are similar to those of the analogous conventional mesogens and hence, can be rationalized without making any special assumptions concerning the conformational distribution of the lateral alkyl chain. 相似文献
903.
H. A. Levine R. Quintanilla L. E. Payne 《Mathematical Methods in the Applied Sciences》1989,11(1):71-77
We consider a three-dimensional hyperelastic cylinder in Ω = D × [0, ∞]. We study the asymptotic behaviour of the deformations of the cross-sections in an equilibrium state. In this case we show that the solutions either have exponential decay or exponential growth. We give some initial conditions such that the latter case occurs. 相似文献
904.
The measurement of the inertial mass of the antiproton and proposed antihydrogen formation experiments require antiprotons
stored in ion traps, cooled to very low (4K) temperatures. Techniques to cool the trapped antiprotons from energies around
1 keV are discussed. Coupling to an external circuit produces cooling times of order 103 s, which may be reduced somewhat with negative feedback. Adiabatic reduction of the trapping potential produces significant
cooling when the particle energies are substantially less than the well depth. Most promising is cooling via energy-transferring
collisions to a cooled cloud of electrons simultaneously trapped with the antiprotons. Electron cooling times are of order
1 s, and strongly depend on electron number and density. 相似文献
905.
F. F. Dedus L. I. Kulikova S. A. Makhortykh N. N. Nazipova A. N. Pankratov R. K. Tetuev 《Moscow University Computational Mathematics and Cybernetics》2007,31(2):49-53
The analysis problem for genetic sequences is formulated from the viewpoint of modern mathematical and information approaches. Statistical, correlative, entropic, and spectral approaches are considered. A brief introduction into the background of the problem is given. Genesis of a new interdisciplinary subject area, bioinformatics, a science considering application of computer methods in biological studies, is analyzed. New approaches to studying macromolecular systems on the basis of combined spectral-analytic technologies are proposed. Estimates of the algorithmic complexity of implementation of the proposed approaches are presented. 相似文献
906.
S. Feng K. Halterman P.L. Overfelt J.M. Elson G.A. Lindsay M.J. Roberts 《Applied Physics A: Materials Science & Processing》2007,87(2):235-244
We present an overview of some of our work on transmission properties and mode characteristics of layered metamaterials and
their potential applications. In particular, we will show how layered metamaterials exhibit unusual transmission properties
and unconventional features of guided modes, such as resonance-induced transparency in multilayer structures and slope reversal
of dispersion curves in coupled waveguides.
PACS 78.67.-n; 73.21.Ac; 61.46.+w; 42.25.Bs; 42.82.Et 相似文献
907.
M.L.H. Gruwel P. Latta M. Tanasiewicz V. Volotovskyy M. Šramek B. Tomanek 《Applied Physics A: Materials Science & Processing》2007,88(4):763-767
Magnetic resonance imaging (MRI) of teeth is an emerging application area which is still in development. Previous investigations
did not fully focus on potential in vivo applications. Using 1H and 31P MRI, we obtained ex vivo microimages of teeth with a silent single point imaging (SPI) technique. 1H Images with an in-plane resolution of 310×310 μm2 were obtained. Utilizing sine-shaped gradient ramps significantly reduced the sound pressure level of the experiment to that
of background noise. 1H magnetic resonance spectroscopy (MRS) was used to characterize the major components in the observed resonance. The spin–spin
(T2) relaxation times of water in enamel and dentin differed by at least one order of magnitude. Three-dimensional surface reconstruction
of the data allowed for complete visualization of the tooth’s surface while volume reconstruction displayed the internal geometry.
PACS 82.56.Na; 83.85.Fg; 87.61.-c; 87.19.-j; 43.50.Cb 相似文献
908.
S. L. Grigor’ev 《Technical Physics》2002,47(2):156-159
Inversion in the structure of polyaminoacids and proteins is discussed, and the electrodynamic quantum-optical model of a neuron is constructed. The feasibility of the quantum-logical summation of exciting pulses by a nanomembrane is considered. The model is consistent with the physiology foundations and assumes implementation by means of techniques used in microelectronics, integrated optics, and nanooptics. 相似文献
909.
Suppose that K
d is compact and that we are given a function fC(K) together with distinct points xiK, 1in. Radial basis interpolation consists of choosing a fixed (basis) function g :
+→
and looking for a linear combination of the translates g(|x−xj|) which interpolates f at the given points. Specifically, we look for coefficients cj
such that
has the property that F(xi)=f(xi), 1in. The Fekete-type points of this process are those for which the associated interpolation matrix [g(|xi−xj|)]1i,jn has determinant as large as possible (in absolute value). In this work, we show that, in the univariate case, for a broad class of functions g, among all point sequences which are (strongly) asymptotically distributed according to a weight function, the equally spaced points give the asymptotically largest determinant. This gives strong evidence that the Fekete points themselves are indeed asymptotically equally spaced. 相似文献
910.
A. A. Gavriliuk A. L. Semenov A. Yu. Mokhovikov D. V. Prudnikov D. A. Shiryaev 《Technical Physics》2006,51(6):746-751
The magnetic and magnetoelastic parameters of Fe64Co21B15 and Fe81.5B13.5Si3C2 amorphous ferromagnetic alloys treated by direct electric current in air are studied as functions of the applied magnetic field and current density. The samples of the alloy have the form of narrow strips with different lengths. It is found that the magnetoelastic parameters of the dc-treated alloys depend on the magnetic field in a qualitatively different way. From the behavior of the magnetic and magnetoelastic parameters of the alloys in the magnetic field a model of magnetization nonuniform distribution in amorphous ferromagnetic alloys subjected to dc treatment is proposed. 相似文献