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111.
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Yasuyuki Tsuboi Kensaku Okada Shoji Ishizaka Noboru Kitamura 《Analytical sciences》2005,21(3):303-308
We found that alpha-diketones (2,3-butanedione (BD) and 1-phenyl-1,2-propanedione (PPD)) were very suitable luminescence probes for studying the properties of a perfluorinated solvent (i.e., fluorous solvent; perfluoromethylcyclohexane (PFMC)), since these compounds were soluble in PFMC and showed long-lived phosphorescence even at room temperature. The phosphorescence lifetime (tau(p)) of BD in PFMC (650 micros) was much longer than that in cyclohexane (CH, 270 micros). The longer tau(p) value of BD in PFMC was ascribed to the variation of the intersystem crossing rate constant (k(isc)) from the excited triplet state (T1) to the ground state (S0) with the solvent. Some possible reasons for the change in k(isc) were discussed in terms of solute-solvent interactions. Furthermore, by utilizing phosphorescence quenching of BD by pyrene, we, determined a rate constant of the diffusion-controlled reaction in PFMC. Characteristic behaviors of mixing/separation processes between PFMC and a common organic solvent observed by Schlieren photographs were also reported. 相似文献
113.
The orientational photorefractive properties of photorefractive mesogenic composites have been investigated by means of two-beam coupling and degenerate four-wave mixing. Photorefractive mesogenic composites, consisting of low molar mass liquid crystals, polymer, and photoconductive sensitizer, constitute novel organic materials possessing high performance photoreractivity. The refractive index change was estimated on the basis of the theory of two-beam coupling and four-wave mixing, and large index modulation of over 0.01 was obtained. 相似文献
114.
S.V. Marchese E. Innerhofer R. Paschotta S. Kurimura K. Kitamura G. Arisholm U. Keller 《Applied physics. B, Lasers and optics》2005,81(8):1049-1052
We demonstrate room temperature femtosecond optical parametric generation with high average output power in periodically poled
MgO-doped stoichiometric LiTaO3. Direct pumping with 725-fs pulses from a passively mode-locked thin disk laser at 1030 nm resulted in stable 1.5 W average
signal power at 1484 nm at the full laser repetition rate of 59 MHz. With this demonstration we achieved a significant simplification
of our recently presented red-green-blue laser source because no temperature stabilization of any nonlinear crystal is required.
PACS 42.65.Yj; 42.70.Mp; 42.79.Nv 相似文献
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