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排序方式: 共有210条查询结果,搜索用时 15 毫秒
71.
72.
73.
The effect of the three different surfactants, sodium dodecyl sulfate (SDS), diethylhexyl sodium sulfosuccinate (AOT), and taurodexycholic acid sodium salt (STDC) on the nonaqueous capillary electrophoretic separations of hydrophobic compounds were compared with formamide containing 20 mM K2HPO4 as electrolyte solvent. Separations of all selected uncharged hydrophobic compounds, e.g., p-arylacetophones were shown to be strongly dependent on the kind of surfactant. The electrolyte containing 180 mM SDS provided the best result for the selected samples. 相似文献
74.
Shigeyuki Yagi Ryuhei Yamada Norihiro Tsuji Shinji Murakami Toru Takagishi 《Supramolecular chemistry》2013,25(3):293-297
Abstract A porphyrin dimer with a polyether linkage was newly synthesized and its conformational change triggered by complexation with an sodium cation was examined. It was confirmed by 1H NMR titration experiments that the dimer bearing a pentaoxyehtylene linkage (1b) was effectively formed a 1:1 complex with a sodium perchlorate. A detailed investigation of the CIS values for the protons confirmed that the complex of 1b?Na+ adopts a slipped face-to-face conformation. 相似文献
75.
Fukushima K Funatsu K Ichimura A Sasaki Y Suzuki M Fujihara T Tsuge K Imamura T 《Inorganic chemistry》2003,42(10):3187-3193
Rhodium(III) porphyrin complexes, [Rh(4-PyT(3)P)Cl](4) (1) and [Rh(2-PytB(3)P)Cl](2) (2) (4-PyT(3)P = 5-(4-pyridyl)-10,15,20-tritolylporphyrinato dianion, 2-PytB(3)P = 5-(2-pyridyl)-10,15,20-tri(4-tert-butyl)phenylporphyrinato dianion), were self-assembled and characterized by (1)H nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electron spray ionization-mass spectroscopy methods. The spectroscopic results certified that the rhodium porphyrin complexes 1 and 2 have a cyclic tetrameric structure and a cofacial dimeric structure, respectively. The X-ray structure analysis of 1 confirmed the cyclic structure of the complex. The Soret bands of both oligomers were significantly broadened by excitonic interactions between the porphyrin units, compared to those observed for a corresponding analogue of Rh(TTP)(Py)Cl (TTP = 5,10,15,20-tetratolylporphyrinato dianion, Py = pyridine). Stepwise oxidation of the porphyrin rings in the oligomers was observed by cyclic voltammetry. The oligomers 1 and 2 are very stable in solution, and they slowly undergo reactions with pyridine to give corresponding monomer complexes only at high temperatures (approximately 80 degrees C). 相似文献
76.
We have investigated a waveguide bend having enhanced curvature with reduced loss. The waveguide width is made wider toward the inner side of the bend. The numerical analysis, by means of the beam propagation method, showed that the loss of the proposed bend is lower than that of an abrupt bend or a smooth bend of constant curvature. For a typical waveguide, we have optimized the structure of the bend and achieved one order of loss reduction in comparison with an abrupt bend of the same angle. 相似文献
77.
Kenzo Yamaguchi Masamitsu Fujii Tadanobu Niimi Masanobu Haraguchi Toshihiro Okamoto Masuo Fukui 《Optical Review》2006,13(4):292-296
A micrometer-sized nonlinear optical resonator constituted of a silica microsphere coated with J-aggregates has been fabricated
by the sol-gel process. We determined the scattering light spectrum and discuss the application of the observed effect for
the realization of an optical switching element. Optical evaluation of the sphere has been performed in the attenuated-total-reflection
(ATR) configuration. We excited a whispering gallery mode and measured the nonlinear ATR signal dependence on excitation intensity.
The experimental result agrees very well with the simulation results obtained using the Mie theory and the finite-difference
time-domain method taking into account optical Kerr nonlinearity. The permittivity of the film of J-aggregates was measured
by ATR method at several wavelengths and the value at the desired wavelength was determined by extrapolation using the Lorentz
function. 相似文献
78.
Toru Takagishi Kiyoaki Yoshikawa Nobuhiko Kuroki Hiroshi Kozuka Masaru Mitsuishi 《Journal of polymer science. Part A, Polymer chemistry》1984,22(1):185-194
The binding of 4′-dibutylaminoazobenzene-4-sulfonate (butyl orange, BO) and 1-amino-4-methylaminoanthraquinone-2-sulfonate (AQ) by crosslinked polyvinylpyrrolidone and the competition between BO and AQ for binding sites of the polymer were examined. The equilibrium data showed competitive binding. Thus the intrinsic binding constants and the number of binding sites can be evaluated easily and precisely by competitive binding. The thermodynamic parameters that accompained the binding were calculated from the intrinsic binding constant and its temperature-dependence. The thermodynamic data for BO showed that the binding process is athermal and stabilized entirely by the entropy term. The binding of BO to the polymer is entropically favorable as a result of the operation of the hydrophobic effect. In contrast, with AQ a favorable free energy for a dye-polymer complex formation is associated with a large negative enthalpy and a small entropy. Therefore it is likely that the binding of AQ occurs by energetic forces and that the large aromatic ring of the dye contributes to the binding energy. On the average, BO and AQ can bind to the crosslinked polymer to the extent of 1 dye/ca 73 basemol in 0.1M tris-acetate buffer, pH 7.0. 相似文献
79.
Microelectrochemical approach to induce local cell adhesion and growth on substrates 总被引:1,自引:0,他引:1
Kaji H Kanada M Oyamatsu D Matsue T Nishizawa M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(1):16-19
The nature of an albumin-coated substrate that blocks protein adsorption and cell adhesion was rapidly switched to cell-adhesive by exposure to an oxidizing agent such as HBrO. This finding has enabled cellular pattern drawing even on a single-cell level by closely scanning a microelectrode above the substrate and electrochemically producing the agent at the tip of the electrode. The present microelectrochemical cell patterning is applicable even for a previously cell-patterned substrate and for a grooved substrate. These unique technical features will have impacts on a variety of cell-based studies that require the analysis of heterotypic cell-cell interactions and cellular arrangement on an uneven surface such as semiconductor devices. 相似文献
80.
Haruyuki Okamura Shogo Toda Masahiro Tsunooka Masamitsu Shirai 《Journal of polymer science. Part A, Polymer chemistry》2002,40(17):3055-3062
Photocrosslinkable systems with thermally cleavable properties based on blends of poly(vinyl phenol) (PVP) and diepoxides were investigated. Thermally cleavable diepoxides as crosslinkers were prepared and characterized. As a thermally cleavable linkage, a tertiary ester moiety was incorporated into the crosslinker molecule. PVP/crosslinker blended films containing photoacid generators (PAGs) became insoluble in solvents after UV irradiation and subsequent post‐exposure‐bake (PEB) treatment. With a rise in the PEB temperature, the insoluble fraction of the irradiated films increased, passed through a maximum value, decreased, and increased again at elevated baking temperatures. The insolubilization profiles of the irradiated films were complicated and strongly dependent on the type of PAG used, the structure of the crosslinkers, and the PVP/crosslinker ratio. A mechanism for the thermal degradation was studied with Fourier transform infrared spectroscopy. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3055–3062, 2002 相似文献