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21.
Masahiro Terashima Takuya Miyayama Tetsuro Shirao Hin Wai Mo Yasuhiro Hatae Hiroshi Fujimoto Katsumi Watanabe 《Surface and interface analysis : SIA》2020,52(12):948-952
Low-energy inverse photoelectron spectroscopy (LEIPS) and ultraviolet photoelectron spectroscopy (UPS) incorporated into the multitechnique XPS system were used to probe the ionization potential and the electron affinity of organic materials, respectively. By utilizing gas cluster ion beam (GCIB), in situ analyses and depth profiling of LEIPS and UPS were also demonstrated. The band structures of the 10-nm-thick buckminsterfullerene (C60) thin film on Au (100 nm)/indium tin oxide (100 nm)/glass substrate were successfully evaluated in depth direction. 相似文献
22.
Shinichi Kinugasa Hisae Nakahara Jun-Ichi Kawahara Yoshinori Koga Haruo Takaya 《Journal of Polymer Science.Polymer Physics》1996,34(3):583-586
Static light scattering measurements were performed on dilute solutions of monodisperse poly(ethylene oxide) (PEO) in methanol at 25°C. PEOs of five different molecular weights ranging from nominal Mw = 8.6 × 104 to 9.13 × 105 were used. Linear Zimm plots were obtained for all the PEO samples: no downturn was observed at small angles, indicating that no large aggregates of PEO molecules exist in the solution. From the plots, values of the weight-average molecular weight, Mw, the radius gyration, RG, and the second virial coefficient, A2, were successfully determined for respective PEOs. Observed relationship between RG and Mw indicates that methanol is certainly a good solvent for the polymer. © 1996 John Wiley & Sons, Inc. 相似文献
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Dilute aqueous solutions of dodecyl-benzenesulfonic acid sodium salt (DBS-Na) and polyoxyethylenenonylphenyl ethers (PONPEs) were ultrasonically atomized. The surfactants were concentrated in collected mist droplets. The enrichment ratio increased with decreasing surfactant concentration. Depending on the surfactant’s molecular weight and affinity to water, different enrichment ratio was observed in the range of low feed concentrations. For anionic surfactant, DBS-Na, the enrichment ratio was significantly improved by KCl addition and a peak appeared on the plot of the ratio against KCl concentration. Addition of NaCl or CaCl2 · 2H2O to the surfactant solution also enhanced the enrichment ratio; however, the effect was relatively small. Such behaviors of the ratio were interpreted as enhanced interfacial adsorption of the surfactant and a lack of supply of surfactant monomers from liquid bulk because of slow breaking of surfactant micelles. Time required for collecting an amount of mist was also observed. Among the three salt systems, the time for KCl system was twice as long as others. This fact suggested that the formation of smaller droplets in KCl system. 相似文献
26.
[reaction: see text] A concise method for the preparation of 1-acyl-4-alkoxy- or 1-acyl-4-alkylsulfanylnaphthalenes has been developed by the reaction of o-ethynylbenzoates or benzothioates with vinyl ethers, in the presence of a catalytic amount of PtCl(2). It is proposed that the reaction proceeds through [3 + 2]-cycloaddition of the platinum-containing carbonyl ylides followed by 1,2-alkyl migration. 相似文献
27.
Takaya Terashima Makoto Ouchi Tsuyoshi Ando Mitsuo Sawamoto 《Journal of polymer science. Part A, Polymer chemistry》2011,49(5):1061-1069
Oxidation of sec‐alcohols was investigated with ruthenium‐bearing microgel core star polymer catalysts [Ru(II)‐Star]. The star polymer catalysts were directly prepared via RuCl2(PPh3)3‐catalyzed living radical polymerization of methyl methacrylate (MMA), followed by the arm‐linking reaction with ethylene glycol dimethacrylate ( 1 ) in the presence of diphenylphosphinostyrene ( 2 ). The Ru(II)‐Star efficiently and homogeneously catalyzed the oxidation of 1‐phenylethanol ( S1 ) to give a corresponding ketone (acetophenone) in higher yield (92%) than the analogs of polymer‐supported ruthenium complexes. Importantly, the star catalyst afforded high recycling efficiency in the oxidation. They held catalytic activity against three times catalysis even though they were recovered under air‐exposure, whereas the conventional RuCl2(PPh3)3 lost the activity for same recycling procedure due to the deactivation by oxygen. The stability of the star catalysts during the recycle experiment was confirmed by detailed spectroscopic characterization. The star polymers also catalyzed oxidation for a wide range of sec‐alcohols with aromatic and aliphatic groups. The substrate affinity was different from that with RuCl2(PPh3)3, suggesting the unique selectivity caused by the specific structure. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
28.
Minoru Ishikura Machiko Kamada Izumi Oda Tsukasa Ohta Masanao Terashima 《Journal of heterocyclic chemistry》1987,24(2):377-386
The reaction of various lithium tributylheteroarylborates with allylic bromides in the presence of copper(I) cyanide furnished the regioselective allylation at the heteroaryl ring. 相似文献
29.
Eiji Takahashi Hikaru Takaya Dr. Takeshi Naota Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(16):4793-4802
The first vapochromic organic crystals are described with respect to their preparation, color change, adsorption/desorption properties, crystal structures, and color‐change mechanism. Non‐solvatochromic, 1,4,5,8‐naphthalene‐tetracarboxylic diimide (NDI) derivatives 1 a bearing two pyrrole imine (PI) tethers have been used as a motif for the crystal packing template. Red‐purple vapochromic solid 3 was prepared by evacuation of orange crystals 2 (equivalent to 1 a ?2 MeOH), obtained by recrystallization of 1 a from MeOH. Solid 3 showed high‐adsorption ability and unprecedented vapor‐dependent color changes upon exposure to a variety of organic vapors, whereas light brown amorphous solid 1 a , did not show vapo‐ or solvatochromic behavior toward any organic solvent. The strong adsorption capability of 3 was confirmed by TGA experiments and adsorption/desorption isotherms. Analysis of the solid‐state UV/Vis analysis revealed that the vapor‐dependent color changes of 3 were owed to the specific interference of solvent vapors with its broad CT absorbance at λ=450–650 nm. Packing structures of 1 a in orange crystals 2 , red‐purple solid 3 , and regenerated orange solid 2 were unequivocally established by single crystal and synchrotron powder X‐ray diffraction, respectively. Molecular structures and arrays of 1 a in these materials indicated that 1) unit 1 a had an S‐shaped folded conformation in 2 and 3 by intramolecular donor–acceptor interactions between NDI and two PI units; 2) inclusion of the guest vapor into the S‐shaped template decreased the intramolecular PI‐NDI interactions, accompanied by increasing intermolecular NDI‐NDI and PI‐PI interactions; and 3) such flexible, open–close motions of the S‐shaped template could be repeated during reversible adsorption/desorption processes without degradation of crystal packing. The adsorption properties and mechanism of molecular shape‐dependent vapochromic behavior of 3 are discussed with reference to experimental results, crystallographic data, and theoretical calculations. 相似文献
30.
Dynamic properties of combustion instability in a lean premixed gas-turbine combustor 总被引:1,自引:0,他引:1
We experimentally investigate the dynamic behavior of the combustion instability in a lean premixed gas-turbine combustor from the viewpoint of nonlinear dynamics. A nonlinear time series analysis in combination with a surrogate data method clearly reveals that as the equivalence ratio increases, the dynamic behavior of the combustion instability undergoes a significant transition from stochastic fluctuation to periodic oscillation through low-dimensional chaotic oscillation. We also show that a nonlinear forecasting method is useful for predicting the short-term dynamic behavior of the combustion instability in a lean premixed gas-turbine combustor, which has not been addressed in the fields of combustion science and physics. 相似文献