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991.
Aïcha Kermaoui Charles Barthou Jean-Pierre Denis Bernard Blanzat 《Journal of luminescence》1984,29(3):295-308
The optical properties of Tm3+ in a fluorophosphate glass are reported. Oscillator strengths and Ωλ parameters for Tm3+ were calculated. Energy transfer between Ce3+ → Tm3+, Tm3+ → Eu3+ and Tm3+ → Tb3+ were measured at room temperature and interpreted using the Yokota and Tanimoto scheme. Fluorescence decay results seem to support the hypothesis of a diffusion-limited relaxation. The effects of Tb3+ and especially Ce3+ on the fluorescence of Tm3+ ion point out the interest of these dopants for obtaining a better emission of Tm3+ at 450 nm. 相似文献
992.
993.
994.
Gregory A. Dilisi Charles Rosenblatt Robert B. Akins Anselm C. Griffin Uma Hari 《Liquid crystals》1992,11(1):63-71
The dialkoxyphenylbenzoate monomer '5005' (C5H11OC6H4COOC6H4OC5H11) and its dimer were aligned parallel to a buffed polyimide-coated glass substrate. A magnetically induced Freedericksz transition in both thick and thin cells was used in conjunction with a capacitance technique to determine the anchoring strength coefficient Was a function of temperature in the nematic phase. It was found that for both monomer and dimer, Wincreases with decreasing temperature. The anchoring coefficient for the dimer, however, was found to be an order of magnitude larger than for the monomer at comparable reduced temperatures. The splay elastic moduli were also determined for both species, and found to be of comparable magnitude, consistent with previous results. 相似文献
995.
996.
Charles S. Tapiero 《European Journal of Operational Research》1983,12(4):348-356
This paper presents a stochastic diffusion model which incorporates advertising word-of-mouth effects. The model defines a 3 variate stochastic process based on explicit assumptions regarding consumer behavior and consumers' response to advertising. The model generalizes a wide variety of advertising models and in addition includes several classes of consumers, interaction effects between these consumers and, of course, a stochastic framework that may be used for assessing the risk implications of advertising policies and for empirical analyses purposes. 相似文献
997.
Charles Martin E.T. Arakawa T.A. Callcott J.C. Ashley 《Journal of Electron Spectroscopy and Related Phenomena》1985,35(2):307-317
The results of experiments on low energy electrons passing through thin amorphous carbon films are reported. For electron energies between 50 and 3000 eV, electron attenuation lengths were determined by electron transmission measurements through carbon films of thicknesses between 81 and 210 Å. The density of these amorphous carbon films was also obtained by a sink—float method and found to be 1.90 ± 0.05 g cm?3. The electron attenuation length for inelastic scattering was found to increase monotonically from approximately 10 to 55 Å over the 50 to 3000 eV range. Over the 500–3000 eV energy region, the results are in good agreement with mean free paths calculated using optically measured dielectric functions. 相似文献
998.
Mitsuru Ueda Toshihisa Kumakura Yoshio Imai Charles U. Pittman Easley Wallace 《Journal of polymer science. Part A, Polymer chemistry》1984,22(1):85-96
The effect of solvent in homo- and copolymerizations of methacryloyl fluoride (MAF) was investigated in various aromatic solvents. In these solvents, there is a significant effect on the rate of polymerization, on the tacticity of the resulting poly(methacryloyl fluoride), and on the copolymerization of MAF with methyl methacrylate (MMA). The equilibrium constants between MAF and aromatic solvents were determined from NMR spectroscopic measurements. These results indicated that the solvent effect on the MAF polymerization stems from changes in reactivity of MAF induced by the strong MAF–solvent interaction as well as stabilization of the MAF radical by solvents. Copolymerization of MAF with both p-methoxystyrene (MSt) and p-nitrostyrene (NSt) was also studied. 相似文献
999.
1000.
Contact angle hysteresis, drop shape, and drop retention were studied with a tiltable plane. Contact liquids were water and ethylene glycol. Four polymers and silicon wafers were used as substrates. When the plane was inclined, the shape of drops distorted, exhibiting advancing and receding contact angles. Drops remained stationary until a critical angle of tilt was exceeded, and then they began to move. The difference in the advancing and receding contact angles, or contact angle hysteresis, ranged from 9° to 66°, depending on the liquid and the substrate. Roughness did not seem to influence the hysteresis as much as the chemical nature of the surfaces. Elongation and back-to-front asymmetry were greater on surfaces with high hysteresis. We found a linear correlation between the aspect ratio of drops and their contact angle hysteresis. Also, the retentive force increased with elongation of the drops. 相似文献