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An apparatus is described that enabled us to carry out a quantitative kinetic investigation of rather quick physicochemical transformations of divided solids by means of an emission of radioactive gas, as in the emanation method. Especially the details of the reaction cells are given in which surface area measurements by the BET method are also performed, and of the low volume scintillation chamber. Its high efficiency does not depend on the nature of the gas. The diverse components of the device ensure a good quality of pure atmosphere or vacuum, rapid and precise temperature setting and control, and reproducible sweeping of the radioactive gas escaping from the sample. 相似文献
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Pierre-Olivier Bussière Jérémy Peyroux Geneviève Chadeyron Sandrine Therias 《Polymer Degradation and Stability》2013
The photochemical behaviour of polymer–nanoparticles/nanocomposites has been studied depending on the geometry of the nanofiller and an overview of the studies reported in the last decade is tentatively given. Depending on their functionality, nanoparticles can impact the durability of the nanocomposite materials under light irradiation. The behaviour to UV-light exposure in presence of oxygen of various types of nanocomposites with clays, LDH and carbon nanotubes has been investigated and recent progress on the influence of functional nanoparticles on the polymer photodegradation is reported. The influence of photocatalytic (ZnO and TiO2) nanoparticles and phosphors on the photooxidation of the polymeric matrix and the durability of the material properties are characterized. From a general point of view, the stabilization strategy of polymer nanocomposites must be adapted depending on the nanofiller. 相似文献
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This Note presents an experimental vibro-acoustic set-up that aims to reproduce the energy pumping phenomenon between an acoustic medium and an essentially nonlinear oscillator. It shows a one-way irreversible transfer of energy between the first acoustic mode in a tube and a thin visco-elastic membrane. To cite this article: B. Cochelin et al., C. R. Mecanique 334 (2006). 相似文献
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M. C. Abreu M. Alimi C. Baglin A. Baldit G. P. Barreira M. Bedjidian P. Bordalo S. Borenstein J. Britz A. Bussiere P. Busson A. Casaca R. Cases J. Castor C. Charlot B. Chaurand D. Contardo E. Descroix A. Devaux J. Fargeix X. Felgeyrolles P. Force L. Fredj J. M. Gago C. Gerschel P. Gomes P. Gorodetzky J. Y. Grossiord A. Guichard J. P. Guillaud R. Haroutunian L. Kluberg L. Kraus G. Landaud I. Linck C. Louren?o A. Maio L. Peralta M. Pimenta J. R. Pizzi C. Racca S. Ramos A. Romana R. Salmeron A. Sinquin P. Sonderegger J. Varela NA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,38(1):129-133
The like-sign dimuons copiously recorded in the NA 38 experiment both inp-U and O?U reactions at 200 GeV/nucleon are interpreted as resulting from decays of π andK mesons in comparable proportions. The ++/?? ratio is large (?1.7) and ascribed to theK + being more copiously produced than theK ?. Both the average transverse momentum and the ++/?? ratio are comparable forp-U and O?U reactions, and both increase only slightly with the transverse energyE T . 相似文献
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This paper presents results obtained within the scope of a collaboration between the “Laboratoire de Mécanique et d'Acoustique”
(Marseille, France), the “Laboratoire de Mécanique des Fluides et d'Acoustique” of the Ecole Centrale (Lyon, France) and the
“Laboratoire de Vibrations et d'Acoustique” of the Institut National des Sciences Appliquées (Lyon, France). The main aspect
of this collaboration is to establish a comparison between a measured and a model vibro-acoustics response of a thin cylindrical
pipe excited by a turbulent internal flow. After a brief review of the literature, a model of the response of the shell, based
on a matched asymptotic expansion, is given. Some numerical results are also given. The spectral density of the acceleration
of the shell is compared with experimental results.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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The addition of tin to iridium-alumina catalysts strongly inhibits catalytic properties of iridium. Tin Mössbauer spectroscopy was applied to Ir-Sn/Al2O3 catalysts and to model mechanical mixtures between SnO2 and Al2O3, Ir-SnO2 and Al2O3 and Ir-Al2O3 and SnO2, during reduction by H2. The final oxidation state of tin (Sn(II) or Sn(0) alloyed to Ir when Ir is present) can be explained by the presence of mobile tin species during reduction. Ir-Sn alloys are responsible for the inhibition of catalytic properties. 相似文献
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Pierre-Olivier Goffard Stéphane Loisel Denys Pommeret 《Methodology and Computing in Applied Probability》2017,19(1):151-174
A numerical method to compute bivariate probability distributions from their Laplace transforms is presented. The method consists in an orthogonal projection of the probability density function with respect to a probability measure that belongs to a Natural Exponential Family with Quadratic Variance Function (NEF-QVF). A particular link to Lancaster probabilities is highlighted. The procedure allows a quick and accurate calculation of probabilities of interest and does not require strong coding skills. Numerical illustrations and comparisons with other methods are provided. This work is motivated by actuarial applications. We aim at recovering the joint distribution of two aggregate claims amounts associated with two insurance policy portfolios that are closely related, and at computing survival functions for reinsurance losses in presence of two non-proportional reinsurance treaties. 相似文献
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P. Bussiere A. Laurent E. Junod 《Journal of Radioanalytical and Nuclear Chemistry》1969,2(3-4):211-217
A method applicable for serial determination of traces of chlorine in SiO2−Al2O3 catalysts by neutron activation is described. The results are evaluated by means of a computer. The38Cl activity is subtracted from the activity of the interfering components (56Mn,24Na) and this enables a direct γ-spectrometric determination. In praxis ten samples should be irradiated simultaneously and
for this reason 3 standards are irradiated together with the samples to correct for the fluxus gradient. The reproducibility
of the method is better than 2 per cent for 10–300 mg samples with a Cl content of 10 ppm.
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