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排序方式: 共有362条查询结果,搜索用时 640 毫秒
31.
32.
Zeina Al Masry Sophie Mercier Ghislain Verdier 《Methodology and Computing in Applied Probability》2017,19(1):213-235
In reliability theory, many papers use a standard Gamma process to model the evolution of the cumulative deterioration of a system over time. When the variance-to-mean ratio of the system deterioration level varies over time, the standard Gamma process is not convenient any more because it provides a constant ratio. A way to overcome this restriction is to consider the extended version of a Gamma process proposed by Cinlar (J Appl Probab 17:467–480, 1980). However, based on its technicality, the use of such a process for applicative purpose requires the preliminary development of technical tools for simulating its paths and for the numerical assessment of its distribution. This paper is devoted to these two points. 相似文献
33.
Résumé On étudie dans cet article un procédé pour obtenir des polycarbonates de bisphénol-A de divers taux de cristallinité. On détermine la variation thermique du module-(10 sec) et la résistance au choc des ces polymères. On étudie également l'influence du recuit sur les propriétés mécaniques.
Summary This paper describes a procedure to obtain polycarbonate of bisphenol A samples of various degrees of crystallinity. The modulus-temperature curves and the impact strength of these materials are investigated. The results show the importance of the annealing procedure on the mechanical properties of these systems.相似文献
34.
Lamoureux N Mercier X Pauwels JF Desgroux P 《The journal of physical chemistry. A》2011,115(21):5346-5353
NCO is a short-lived species involved in NO(x) formation. It has never been quantitatively measured in flame conditions. In the present study, laser-induced fluorescence (LIF) and cavity ring-down spectroscopy (CRDS) were combined to measure NCO radical concentrations in premixed low-pressure flames (p = 5.3 kPa). NCO LIF excitation spectrum and absorption spectrum (using CRDS) measured in a stoichiometric CH(4)/O(2)/N(2)O/N(2) flame were found in good agreement with a simulated spectrum using PGOPHER program that was used to calculate the high-temperature absorption cross section of NCO in the A(2)Σ(+)-X(2)Π transition around 440.479 nm. The relative NCO-LIF profiles were measured in stoichiometric CH(4)/O(2)/N(2)O/N(2) flames where the ratio N(2)O/O(2) was progressively decreased from 0.50 to 0.01 and in rich CH(4)/O(2)/N(2) premixed flames. Then, the LIF profiles were converted into NCO mole fraction profiles from the absorption measurements using CRDS in a N(2)O-doped flame. 相似文献
35.
Thomas Mouton Xavier Mercier Maxime Wartel Nathalie Lamoureux Pascale Desgroux 《Applied physics. B, Lasers and optics》2013,112(3):369-379
This paper presents the study we carried out on the formation of soot particles in low-pressure premixed CH4/O2/N2 flames by using Laser-Induced Incandescence (LII). Flames were stabilised at 26.6 kPa (200 torr). Four different equivalence ratios were tested (Φ = 1.95, 205, 2.15 and 2.32), Φ = 1.95 corresponding to the equivalence ratio for which LII signals begin to be measurable along the flame. The evolution of the LII signals with laser fluence (fluence curve), time (temporal decay) and emission wavelength is reported at different heights above the burner. We specifically took advantage of the low-pressure conditions to probe with a good spatial resolution the soot inception zone of the flames. Significant different behaviours of the fluence curves are observed according to the probed region of the flames and Φ. In addition, while the surface growth process is accompanied by an increase in the LII decay-times (indicator of the primary particle diameter) at higher Φ, decay-times become increasingly short at lower Φ reaching a constant value along the flame at Φ = 1.95. These behaviours are consistent with the detection of the smallest incandescent particles in the investigated flames, these particles having experienced very weak surface growth. Flame modelling including soot formation has been implemented in flames Φ = 2.05 and 2.32. Experimental quantitative soot volume fraction profiles were satisfactorily reproduced by adjusting the fraction of reactive soot surface available for reactions. The qualitative variation of the computed soot particle diameter and the relative weight of surface growth versus nucleation were consistent with the experimental observations. 相似文献
36.
Eliette Pinel Marie‐France Barthe Jrmie De Baerdemaeker Rgis Mercier Sylvie Neyertz N. Dominique Albrola Corine Bas 《Journal of Polymer Science.Polymer Physics》2003,41(23):2998-3010
The microstructures of a series of copolyimide films were characterized with different experimental methods such as density measurements, X‐ray diffraction, ultraviolet‐visible spectrophotometry, positron annihilation spectroscopy, and dynamic mechanical analysis. The experimental data were linked to the chemical structures of the polymers and especially the alicyclic and fluorinated monomers. Some analysis responses were directly dependent on the fluorine atoms and, therefore, did not provide clear information about the microstructures. The chain organization in the amorphous films appeared to be significantly dependent on the effect of the casting solvent. The influence of the alicyclic group content was quite significant for a nonsubstituted diamine but was strongly attenuated with a fluorinated diamine. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2998–3010, 2003 相似文献
37.
H. Moreigne Bayrac M. G. Mercier und G. Cavallero 《Fresenius' Journal of Analytical Chemistry》1895,34(1):770
Ohne Zusammenfassung 相似文献
38.
André Mercier 《General Relativity and Gravitation》1975,6(5):513-536
This paper considers successively: Cosmological Determinism (as an approach to other possible determinisms), the concept of a Cosmic Space (as compared with other concepts of space), Time as being, according to GRG, of a richer nature and of a structure more complicated than thought of by Newton and Kant (especially: spacetime is not a space, but time itself), the idea of a unified theory (based either on the wish to synthesize different dynamics or on a principle that interactions should be unified). A consequence of these considerations is that, possibly, gravitation is not an interaction like other ‘usual’ interactions, much rather it would be an aspect of Time itself. 相似文献
39.
40.
The properties of the solid solution VSe2?xSx 0 ? xnom ? 2 have been investigated for secondary battery application. The phase VSe2 is observed for 0 ? xnom ? 1.2 and the phase V5S8 is found using RX analysis for xnom >1.2. The amount of lithium chemically incorporated in this structure by reaction with n-butyllithium is 2 Li/vanadium for 0 ? xnom ? 0.8 and 1.4 Li/vanadium for V5S8. An electrochemical technique (galvanostatic) indicates that the amount of lithium incorporated depends on the xnom values, the grain size and the discharge rate. The best results are obtained for 0.2 ? xnom ? 0.6 (capacity = 164?172 Ah kg?1 and energy density = 385?465 Wh kg?1). 相似文献