First albedo determination of 2867 Steins, target of the Rosetta mission

We present the first albedo determination of 2867 Steins, the asteroid target o f the Rosetta space mission together with 21 Lutetia. The data were obtained in polarimetric mode at the ESO-VLT telescope with the FORS1 instrument in the V and R filters. Observations were carried out from Jun e to August 2005 covering the phase angle range from 10.3 deg. to 28.3 deg., allowing the determination of the asteroid albedo by the well known experimenta l relationship between the albedo and the slope of the polarimetric curve at th e inversion angle. The measured polarization values of Steins are small, confirming an E-type cla ssification for this asteroid, as already suggested from its spectral propertie s. The inversion angle of the polarization curve in the V and R filters is resp ectively of 17.3 +/-1.5deg. and 18.4+/-1.0 deg., and the corresponding sl ope parameter is of 0.037+/-0.003 %/deg and 0.032+/-0.003 %/deg. On the basis of its polarimetric slope value, we have derived an albedo of 0.45 +/-0.1, that gives an estimated diameter of 4.6 km, assuming an absolute V ma gnitude of 13.18 mag.Comment: 4 pages, 4 figures, letter accepted for pubblication on A&

Microstructural and mechanical characterization of yarns made from carbon nanotubes for the instrumentation of particle beams at CERN

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Generation Of Optical Standing Waves Around Mesoscopic Surface-Structures - Scattering And Light Confinement

Optical scanning probe devices offer an extremely efficient way of collecting local information on the complex structure of optical electromagnetic fields lying near a surface. This paper discusses recent theoretical efforts to develop an efficient method for the calculation of the field distributions in experimentally relevant near-field and integrated optics systems. In order to overcome the obstacles inherent in the matching of the electromagnetic boundary conditions on the surface of complex objects, the discussion is presented in the framework of the integral-equation formalism. This treatment is based on the field-susceptibility Green-function technique applied in real space. Two original numerical schemes, both based on a different discretization procedure, are discussed, and several numerical applications on systems of experimental interest are presented. Particularly, the problem of near-held distribution around three-dimensional objects of various sizes and shapes is investigated as a function of experimental parameters

Field-Induced Manipulation Of Fullerene Molecules With The Stm - A Self-Consistent Theoretical-Study

By applying an appropriate voltage between an STM tip and a metallic substrate, it is possible to induce highly localized electrostatic fields. In this paper, it is shown that the apex of the STM probe, responsible for the resolution, confines an electric field of small lateral extension inside the junction. The change in the potential energy of an adsorbate submitted to such a field is calculated with a self-consistent scheme. A microscopic description of both the tip-apex and the adsorbates is used and the correlations between each polarizable centre are accounted for with a discretized Lippmann-Schwinger equation. Several applications show that our real space approach is extremely attractive for studying electrostatic field distributions in low symmetry systems. Field induced manipulation processes of C-60 molecules are discussed in this context.NA

Этимологический анализ специальных единиц лексико-семантического поля "интеллектуальные энергетические системы" в системе современного английского языка

В данной статье описываются результаты этимологического анализа лексико-семантического поля "Интеллектуальные энергетические системы" современного английского языка. Этимологический анализ проводится в аспекте "семантической эволюции слова", а также принадлежности слова к собственному или заимствованному языковому материалу

Исследование точности отверстий и их усадки в обрабатываемых дорнованием втулках

В работе рассмотрены область применения ,виды дорнов, схема процесса дорнования отверстия, схема параметры дорнования отверстия, плюсы и минусы дорнования, и оборудование для дорнования. Потом использование конечно-элементного программного обеспечения ANSYS для моделирования процесса обработки. Затем проведено исследование зависимости усадки отверстия от натяга, степени толстостенности, механических свойств материала, а также исследована кривизна обработанных отверстий. В заключении изложены выводы о проделанной работе и представлено уравнение описывающее исследованные зависимости.In the work, the scope of application, types of mandrels, a diagram of the mandrel process of a hole, a diagram of the parameters of a mandrel of a hole, the pros and cons of mandrel, and equipment for mandrel are considered. Then the use of ANSYS finite element software to simulate the processing process. Then the study of the dependence of the hole shrinkage on the tightness, the degree of thickness, the mechanical properties of the material was carried out, and the curvature of the machined holes was also investigated. In the conclusion, the conclusions about the work done are presented and the equation describing the investigated dependences is presented