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51.
52.
Debora?S.?F.?Gay Yoshitaka?Gushikem Celso?C.?Moro Tania?M.?H.?Costa Edilson?V.?BenvenuttiEmail author 《Journal of Sol-Gel Science and Technology》2005,34(2):189-195
1,4-phenylenediamine-1-propylsilica hybrid xerogels were obtained for two composition at different temperatures of gelation, from 5 up to 70C. The morphological effects produced by the different gelation temperatures were investigated by using N2 adsorption-desorption isotherms and scanning electron microscopy. The thermal stability of the organic groups and their distribution on the xerogel matrix, i.e. the fraction of the organic groups that were trapped in closed pores, formed during the xerogel synthesis, and the fraction of organic groups present on the surface, were obtained by using infrared thermal analysis. The higher porosity of the xerogels and the higher thermal stability of the organic groups were achieved for samples gelled at 25C. 相似文献
53.
Benoit Gay Rodolphe Vaillon M. P?nar Mengüç 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(2):287-294
A new integral-vector Monte Carlo method (IVMCM) is developed to analyze the transfer of polarized radiation in 3D multiple scattering particle-laden media. The method is based on a “successive order of scattering series” expression of the integral formulation of the vector radiative transfer equation (VRTE) for application of efficient statistical tools to improve convergence of Monte Carlo calculations of integrals. After validation against reference results in plane-parallel layer backscattering configurations, the model is applied to a cubic container filled with uniformly distributed monodispersed particles and irradiated by a monochromatic narrow collimated beam. 2D lateral images of effective Mueller matrix elements are calculated in the case of spherical and fractal aggregate particles. Detailed analysis of multiple scattering regimes, which are very similar for unpolarized radiation transfer, allows identifying the sensitivity of polarization imaging to size and morphology. 相似文献
54.
K Modos S Gaspar P Kirsch M Gay G Ronto 《Journal of photochemistry and photobiology. B, Biology》1999,49(2-3):171-176
A procedure is presented for constructing the spectral sensitivity functions of biological dosimeters, using five polychromatic UV sources possessing different emission spectra. Phage T7 and uracil biological dosimeters have been used for measuring the dose rates of the lamps. Their spectral sensitivity functions consisting of two exponential terms have been constructed. The parameters of the spectral sensitivity functions have been determined by comparing the directly measured and calculated dose-rate values. The parameters of the sensitivity function are accepted as correct values when the deviation of the measured and calculated values is a minimum. Based on the deviations between the constructed and the experimentally determined spectral sensitivities with monochromatic sources, the differences between the measured and calculated results are interpreted. The importance of the correct spectral sensitivity data is demonstrated through the effectiveness spectra of a TL 01 lamp for phage T7 killing, uracil dimerization and erythema induction. 相似文献
55.
Jean Gay Franois Fressin Jean-Pierre Rivet Yves Rabbia Christophe Buisset 《Comptes Rendus Physique》2005,6(10):1169-1175
We present a new type of stellar interfero-coronagraph, the ‘CIAXE’, which is a variant of the ‘AIC’, the Achromatic Interfero-Coronagraph. The CIAXE is characterized by a very simple, compact and fully coaxial optical combination. Indeed, contrarily to the classical AIC which has a Michelson interferometer structure, the CIAXE delivers its output beam on the same axis as the input beam. This will ease its insertion in the focal instrumentation of existing telescopes or next generation ones. Such a device could be a step forward in the field of instrumental search for exoplanets. To cite this article: J. Gay et al., C. R. Physique 6 (2005). 相似文献
56.
Carlos Gay Gary E. Thomas 《Journal of Quantitative Spectroscopy & Radiative Transfer》1981,25(4):351-380
We have developed a new approach toward solving problems of linear radiative relaxation of LTE temperature perturbations in a plane-parallel atmosphere of finite extent. We show that the mathematical problem is one of solving an integral eigenvalue equation, for which non-trivial solutions exist only for discrete values of the radiative relaxation time. The solutions for the spatial part of the perturbation constitute a complete and orthogonal set of basis functions, making it possible to solve more general problems of temperature relaxation. In applying this method to radiative relaxation in the middle atmosphere of earth, we show how the additional influences of photochemical coupling, advection by winds, and eddy diffusion by small-scale turbulence may be easily included using matrix perturbation techniques. We have solved the homogeneous integral equation for a wide variety of vertical thicknesses in an idealized homogeneous slab medium. Adopting a number of different analytic line profiles (rectangular, Doupler, Voigt, and Lorentz) we have obtained numerical solutions using an exponential-kernel method for solving the integral equation. The discrete eigenvalue “spectrum” is presented for vertical optical depths (0–103) at line-center, and is used in solving several initial-value problems for a decaying temperature perturbation. We find that the eigenvalue spectrum is bounded from above by the lowest-order eigenvalue, and bounded from below by the familiar transparent approximation. The dependence of the lowest even eigenvalue on optical depth and the relative separation of the higher eigenvalues are found to depend sensitively on the line profile. 相似文献
57.
C. Dionisi R. Armenteros J. Diaz Ph. Gavillet J.B. Gay A. Gurtu R.J. Hemingway M. Mazzucato P. Trepagnier R. Blokzijl G.G.G. Massaro B. Jongejans J. Engelen J.J. Timmermans R.T. Van De Walle B. Foster P.R. Lamb W.L. McDowell 《Physics letters. [Part B]》1978,78(1):154-157
Evidence is presented for an I = 1 enhancement observed in the reactions K?p→Λ(Σ)K01K±π? at inciden momentum. The mass and width of the proposed new Y1 are, respectively, (1553 ± 7) MeV) and (80 ± 30) MeV. A decay branching ratio is also obtained. 相似文献
58.
T Gay 《The Journal of the Acoustical Society of America》1978,63(1):223-230
The purpose of this experiment was to study the effects of changes in speaking rate on both the attainment of acoustic vowel targets and the relative time and speed of movements toward these presumed targets. Four speakers produced a number of different CVC and CVCVC utterances at slow and fast speaking rates. Spectrographic measurements showed that the midpoint format frequencies of the different vowels did not vary as a function of rate. However, for fast speech the onset frequencies of second formant transitions were closer to their target frequencies while CV transition rates remained essentially unchanged, indicating that movement toward the vowel simply began earlier for fast speech. Changes in both speaking rate and lexical stress had different effects. For stressed vowels, an increase in speaking rate was accompanied primarily by a decrease in duration. However, destressed vowels, even if they were of the same duration as quickly produced stressed vowels, were reduced in overall amplitude, fundamental frequency, and to some extent, vowel color. These results suggest that speaking rate and lexical stress are controlled by two different mechanisms. 相似文献
59.
60.
D. C. Dejongh S. C. Perricone M. L. Gay W. Korytnyk 《Journal of mass spectrometry : JMS》1968,1(1):151-166
The mass spectra of the different forms of vitamin B6, some metabolites and antimetabolites, and some analogs are reported. The free bases are suitable for study, but the 5-phosphates are not sufficiently volatile. The hydrochloride salts dissociate thermally in the inlet system into the free base and HCl and give the spectrum of the free base with the spectrum of HCL superimposed on it. The compounds studied are: pyridoxol, pyridoxamine and pyridoxal, which are different forms of vitamin B6; 4-pyridoxic acid and its lactone, 5-pyridoxic acid lactone, isopyridoxal, 5-formyl-3-hydroxy-2-methylpyridine-4-carboxylic acid, and 3-hydroxy-2-methylpyridine-4,5-dicarboxylic acid, which are vitamin B6 metabolites; α4-and α5-deoxypyridoxol, 3-deoxypyridoxol, and 4- and 5- norpyridoxol, which are antimetabolites and analogs of vitamin B6. 相似文献