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61.
We consider noncommutative line bundles associated with the Hopf fibrations of SUq(2) over all Podle? spheres and with a locally trivial Hopf fibration of S3pq. These bundles are given as finitely generated projective modules associated via 1-dimensional representations of U(1) with Galois-type extensions encoding the principal fibrations of SUq(2) and S3pq. We show that the Chern numbers of these modules coincide with the winding numbers of representations defining them. To cite this article: P.M. Hajac et al., C. R. Acad. Sci. Paris, Ser. I 336 (2003).  相似文献   
62.
We characterize Poisson and Jacobi structures by means of complete lifts of the corresponding tensors: the lifts have to be related to canonical structures by morphisms of corresponding vector bundles. Similar results hold for generalized Poisson and Jacobi structures (canonical structures) associated with Lie algebroids and Jacobi algebroids.  相似文献   
63.
Supported by SFB 170 “Geometrie und Analysis” at the University of G?ttingen  相似文献   
64.
Investigations of photoluminescence and Raman scattering in the ternary Zn1-xMgxSe compounds at 4.2 K were performed both in the Stokes and anti-Stokes regions using cw laser excitation with various wavelengths within the transparency band of the crystals. The anti-Stokes luminescence was observed for the first time in the ternary Zn1-xMgxSe compounds. We have found variations in the shape and position of the Stokes and anti-Stokes luminescence bands with an increase in the band gap energy, which depends on magnesium content. We assume that the anti-Stokes emission is generated by two-step excitation via deep-level centers. It is shown that the low-temperature anti-Stokes photoluminescence can probe the spatial distribution profiles of impurities in the bulk of crystals.  相似文献   
65.
Any directed graph G with N vertices and J edges has an associated line-graph L(G) where the J edges form the vertices of L(G). We show that the non-zero eigenvalues of the adjacency matrices are the same for all graphs of such a family L n (G). We give necessary and sufficient conditions for a line-graph to be quantisable and demonstrate that the spectra of associated quantum propagators follow the predictions of random matrices under very general conditions. Line-graphs may therefore serve as models to study the semiclassical limit (of large matrix size) of a quantum dynamics on graphs with fixed classical behaviour.  相似文献   
66.
Although there exist a number of methods, such as NMR, X-ray, e.g., which explore the hydration of phospholipid bilayers, the solvent relaxation (SR) method has the advantage of simple instrumentation, easy data treatment and possibility of measuring fully hydrated samples. The main information gained from SR by the analysis of recorded “time-resolved emission spectra” (TRES) is micro-viscosity and micro-polarity of the dye microenvironment. Based on these parameters, one can draw conclusions about water structure in the bilayer. In this review, we focus on physical background of this method, on all the procedures that are needed in order to obtain relevant parameters, and on the requirements on the fluorescence dyes. Furthermore, a few recent applications (the effect of curvature, binding of antibacterial peptides and phase transition) illustrating the versatility of this method are mentioned. Moreover, limitations and potential problems are discussed.  相似文献   
67.
Summary This paper deals with the two-dimensional static punch problems in the presence of friction for a periodically layered half-space. Within the framework of the homogenized model of linear elasticity with microlocal parameters [8–11] the exact solutions of the considered problems are obtained. The case of the indentation of the composite body by a rigid rectangular punch has been discussed in detail.
Ebene Kontaktprobleme für ein periodisches elastisches Zweischichten-Komposit
Übersicht In dieser Arbeit wird das zweidimensionale statische Stempelproblem mit Reibung für einen periodisch geschichteten Halbraum betrachtet. Im Rahmen eines Homogenisierungsmodells der linearen Elastizitätstheorie mit mikropolaren Parametern werden die exakten Lösungen der betrachteten Probleme gewonnen. Im Detail wird das Eindringen eines rechteckigen starren Stempels behandelt.
  相似文献   
68.
Experimental investigation and analysis of heat transfer process between a gas-liquid spray flow and the row of smooth cylinders placed in the surface perpendicular to the flow has been performed. Among others, there was taken into account in the analysis the phenomenon of droplets bouncing and omitting the cylinder as well as the phenomenon of the evaporation process from the liquid film surface.In the experiments test cylinders were used, which were placed between two other cylinders standing in the row.From the experiments and the analysis the conclusion can be drawn that the heat transfer coefficients values for a row of the cylinders are higher than for a single cylinder placed in the gasliquid spray flow.
Wärmeübergang an eine senkrecht anf eine Zylinderreihe auftreffende Gas-Flüssigkeits-Sprüh-Strömung
Zusammenfassung Es wurden Messungen und theoretische Analysen des Wärmeübergangs zwischen einer Gas-FlüssigkeitsSprüh-Strömung und den glatten Oberflächen einer Zylinderreihe durchgeführt, die senkrecht zum Sprühstrahl angeordnet waren. Dabei wurde in der Analyse unter anderem das Phänomen betrachtet, daß die Tropfen die Zylinderwand treffen und verfehlen können und daß sich ein Verdampfungsprozeß aus dem flüssigen Film an der Zylinderoberfläche einstellt.Gemessen wurde an einem zwischen zwei Randzylindern befindlichen Zylinder.Die Experimente und die Analyse gestatten die Schlußfolgerung, daß der Wärmeübergangskoeffizient für eine Zylinderreihe höher ist als für einen einzelnen Zylinder in der Sprühströmung.

Nomenclature a distance between axes of cylinders, m - c l specific heat capacity of liquid, J/kg K - c g specific heat capacity of gas, J/kg K - D cylinder diameter, m - g l mass velocity of liquid, kg/m2s - ¯k average volume ratio of liquid entering film to amount of liquid directed at the cylinder in gas-liquid spray flow, dimensionless - k() local volume ratio of liquid entering film to amount of liquid directed at the cylinder in gas-liquid spray flow, dimensionless - L specific latent heat of vaporisation, J/kg - m mass fraction of water in gas-liquid spray flow, dimensionless - M constant in Eq. (9) - p pressure, Pa - p g statical pressure of gas, Pa - p w pressure of gas on the cylinder surface, Pa - p external pressure on the liquid film surface, Pa - r cylindrical coordinate, m - R radius of cylinder, m - T temperature, K, °C - T l, tl liquid temperature in the gas-liquid spray, K, °C - T w,tw temperature of cylinder surface, K, °C - T temperature of gas-liquid film interface, K - U liquid film velocity, m/s - w gas velocity on cylinder surface, m/s - w g gas velocity in free stream, m/s - W l liquid vapour mass ratio in free stream, dimensionless - W liquid vapour mass ratio at the edge of a liquid film, dimensionless - x coordinate, m - y coordinate, m - z complex variable, dimensionless - average heat transfer coefficient, W/m2K - local heat transfer coefficient, W/m2 K - average heat transfer coefficient between cylinder surface and gas, W/m2 K - g, local heat transfer coefficient between cylinder surface and gas, W/m2 K - mass transfer coefficient, kg/m2s - liquid film thickness, m - lg dynamic diffusion coefficient of liquid vapour in gas, kg/m s - pressure distribution function on a cylinder surface - function defined by Eq. (3) - l liquid dynamic viscosity, kg/m s - g gas dynamic viscosity, kg/m s - cylindrical coordinate, rad, deg - l thermal conductivity of liquid, W/m K - g thermal conductivity of gas, W/m K - mass transfer driving force, dimensionless - l density of liquid, kg/m3 - g density of gas, kg/m3 - w shear stress on the cylinder surface, N/m2 - w shear stress exerted by gas at the liquid film surface, N/m2 - air relative humidity, dimensionless - T -T w - w =T wTl Dimensionless parameters I= enhancement factor of heat transfer - m *=M l/Mg molar mass of liquid to the molar mass of gas ratio - Nu g= D/ g gas Nusselt number - Pr g=c g g/g gas Prandtl number - Pr l=clll liquid Prandtl number - ¯r=(r–R)/ dimensionless coordinate - Re g=wgD g/g gas Reynolds number - Re g,max=wg,max D g/g gas Reynolds number calculated for the maximal gas velocity between the cylinders - Sc=m * g/l–g Schmidt number =/R dimensionless film thickness  相似文献   
69.
High-energy gamma-rays emitted in the decay of the giant dipole resonance built on excited states of55Mn nucleus were measured with a bismuth germanate detector. Resonance parameters were extracted from the fits to the experimental spectra. Two new high-energy calibration points originating from slow-neutron capture in germanium isotopes of bismuth germanate crystal are proposed for large-volume BGO detectors.  相似文献   
70.
The lifetimes of five states in the ground band, from spin 6+ up to spin 14+, and of all even states in the gamma band up to spin 12+, have been measured in166Er using the recoil distance method. The reduced electric quadrupole transition probabilities have been determined from the measured lifetimes using previously measured branching ratios, and the mixing between the ground band and theγ-band has been studied. The transitional electric quadrupole moments for the ground band and theγ-band have been deduced and are discussed.  相似文献   
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