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101.
Methylenecyclopentanones were synthesized by the nickel-catalyzed [3+1+1] cycloaddition reactions of alkenyl Fischer carbene complexes with methylenecyclopropanes. The methylenecyclopropane was transformed into the C(2)-symmetric bis-cyclopentapyridazine derivative by reacting with p-toluenesulfonyl hydrazine. 相似文献
102.
Yasunori Nishijima 《Journal of Macromolecular Science: Physics》2013,52(3-4):389-411
The characteristics of photoluminescence are affected by the molecular motions in the local environment of the excited molecule. Hence, by knowing the lifetime of the excited state, various relaxation times of the molecular motions can be estimated from the emission characteristics. In the present paper the effect of the molecular motions manifested in the fluorescence emission, such as the rotational depolarization of fluorescence, the internal quenching of fluorescence due to internal rotation, and the inter-and intramolecular excimer formation, are reviewed and the possible applications of such phenomena to the study of molecular motions in polymer systems are discussed. The application of fluorescence methods provide unique information about the molecular motions in the nanosecond range in polymer solutions, melts, and solids. 相似文献
103.
Molecular recognition of dicarboxylates by a dinuclear zinc(II) complex of 2,2?-binaphthalene bearing di(2-pyridyl)aminomethyl groups at 8- and 8?-positions ([Zn2L]4+) by UV-vis and fluorescence spectral titrations in an aqueous solvent was investigated. In a series of α,ω-dicarboxylate, receptor [Zn2L]4+ showed the highest binding affinity for succinate and UV-vis and fluorescence changes were also largest upon the addition of this guest. In a series of phthalate derivatives, phthalate was strongly bound by [Zn2L]4+. The characteristic UV-vis and fluorescence changes strongly depend on the dihedral angle of two naphthyl groups of the complex [Zn2L]4+· dicarboxylate estimated by spectral titrations and DFT calculations. 相似文献
104.
Anna V. Klassen Makoto Matsukura Osamu Nakamura Vladimir V. Kochurikhin Mikhail A. Ivanov Galina Yu. Orlova Akio Miyamoto Yasunori Furukawa 《Journal of Crystal Growth》2008,310(11):2895-2898
The applicability of the edge-defined film-fed growth (EFG) technique for YbxY(1−x)VO4 (x=0.05, 0.1 and 1) was approved by successful growth of crystals up to 80 mm in length as the thin plates. Low-angle grain boundaries and the crystal coloration as main defects were found. Optimal seed orientation was suggested on the strength of vanadate crystal plate morphology. Optical properties, chemical composition and the crystalline quality were investigated. 相似文献
105.
Anisotropic optical properties and nanostructures of thin films prepared by oblique co-deposition of Ag and SiO2 were studied. At low concentrations of Ag, a columnar structure grew towards the direction of the incident SiO2 vapor and small Ag particles were embedded in that structure. An inhomogeneous distribution of Ag was observed in cases where the Ag was deposited from the opposite side of the surface normal to the direction of the incident SiO2 vapor. This inhomogeneous distribution of Ag particles gives rise to optical anisotropy, i.e., the optical transmittance of p-polarized light varies drastically depending on the angle of incidence, while that of s-polarized light remains unchanged. A possible application of the anisotropic optical absorption properties of Ag---SiO2 hybrid films is in the manufactur of an inorganic thin film polarizer. 相似文献
106.
MgO-doped LN (LiNbO3) fibers were automatically grown by an improved drawing down method. The smallest fiber diameter ever attained was 10 μm and the fluctuation in diameter was reduced to ±0.2 μm. The poling process was done during the growth process by the thermal electric effect. The dislocation which was observed in the X-ray topographs of the optical grade bulk crystals did not appear in the fiber. The fibers and optical grade bulk crystals did not have a uniform distribution of the MgO concentration as determined by electron probe micro analysis (EPMA). 相似文献
107.
Hideto Tsuji Yoshiko Yamamura Tomoyuki Ono Takashi Saeki Hiroyuki Daimon Koichi Fujie 《大分子反应工程》2008,2(6):522-528
Aliphatic dicarboxylic acid/aliphatic diol‐derived polyesters, poly(butylene succinate) and poly(butylene succinate/adipate), have been hydrolytically degraded in the melt in high‐temperature and high‐pressure water over a wide temperature range of 180–300 °C for periods of up to 30 min. The formation/decomposition of succinic acid (SA), adipic acid (AA), and butane‐1,4‐diol (BD), plus the molecular weight change of PBS and PBSA were then investigated. SA and AA were recovered at maximum yields of 65–80%, whereas BD was recovered at a maximum yield of only 30%, probably because of its decomposition. The obtained results were compared with those reported for aliphatic hydroxycarboxylic acid‐derived polyesters and aromatic dicarboxylic acid/aliphatic diol‐derived polyesters.
108.
A possible deduction is proposed of channel length distribution in one-dimensional porous materials from the kinetic data
obtained in isothermal thermogravimetry (TG). The method utilizes the absorption/desorption of small molecules into one-dimensional
nano-channel. In the surface-controlled absorption/desorption, the second derivative with respect to time is directly proportional
to the channel-length distribution function. Even in the diffusion-controlled case, the second derivative with respect to
the square root of time gives rough information on the distribution function. 相似文献
109.
110.
A non‐volatile, bistable, and rewritable organic memory device was successfully fabricated with the layers of poly(2,2,6,6‐tetramethylpiperidine‐1‐oxyl methacrylate) (PTMA) and poly(methyl methacrylate) (PMMA) containing silver salt. The PTMA layer was employed as a p‐dopable material, while the silver salt‐dispersed PMMA layer acted as an n‐dopable material. The ON–OFF ratio between low‐conductivity and high‐conductivity states amounted to more than four orders of magnitude, and the retention time was longer than 103 sec. The device was characterized by excellent rewritability. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献