20 resultados para velar displacement
Resumo:
The mechanism of beam splitting and principle of wide-field-of-view compensation of modified Savart polariscope in the wide-field-of-view polarization interference imaging spectrometer (WPIIS) are analyzed and discussed. Formulas for the lateral displacement and optical path difference (OPD) produced by the modified Savart polariscope are derived by ray-tracing method. The theoretical and practical guidance is thereby provided for the study, design, modulation, experiment and engineering of the polarization interference imaging spectrometers and other birefringent Fourier-transform spectrometers based on Savart polariscopes. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced in ionic liquid (2). The same reaction in [bmim][PF6](1)(where bmim = 1-butyl-3-methylimidazolium) was also studied. It was found that as a reaction medium ionic liquid (2) is better than (1) for nucelophilic displacement reactions.
Resumo:
CaY1-xBO4: xEu was synthesied by solid state reaction method, and the displacement and luminescence of the Eu3+ in CaYBO4 host were studied. Two luminescent centers could be observed at certain Eu3+-concentration, indicating that the Eu3+ occupies two different crystallographic sites. This result shows that the Eu3+ occupies two different Y3+ sites in CaYBO4. The investigation on Eu-O charge transfer bands indicates that the larger distortion or the lower symmetry of Eu3+ site is,the shorter wavelength of the Eu-O charge transfer band is. When the Eu3+-concentration is high (x > 0.10), Eu3+ occupies the sites of Ca2+ and is reduced to Eu2+.
