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231.
Oligomeric polysiloxanes having the spirobenzopyran moiety and various substituents were prepared. The polymers were photochromic; the color changed from colorless to red on UV irradiation and the color faded on visible irradiation or on standing in the dark. The thermal decoloration was depressed by the polar substituents. However, the effect of the bulky substituent, which had been observed in the rigid siloxane resins, was not detected. In the inorganic/organic hybrid siloxane gels, the silica/(spirobenzopyran-bonding polysiloxane) system and the (spirobenzopyran-bonding silica)/polysiloxane system, the thermal decoloration was also affected by the polar substituent introduced into the polysiloxane portion. The effect was larger in the first case than in the second. The result can be interpreted by the term of the preferential diffusion of polar spirobenzopyran to the vicinity of the polar substituents during the gelation. 相似文献
232.
Yoshihiko Gotoh Akira Horii Toshio Ishii Hitoshi Kawanowa Hisami Yumoto Takehiko Gonda 《Crystal Research and Technology》1995,30(6):801-806
“In-Situ” observation of nucleation and growth of Ag crystallites on graphite substrate by vapour deposition was carried out by scanning electron microscope (SEM). Irradiation of the SEM electron beam onto the substrate surface before and during deposition enhanced Ag nucleation. The density of the Ag crystallites was 1010/cm2 in room temperature condensation, but decreased to 109/cm2 in high temperature condensation at 140 °C. When the substrate was heated after room temperature condensation, the density of the Ag crystallites decreased prominently. This means that coalescence of the Ag crystallites takes place as a result of their migration on the substrate. 相似文献
233.
Nurul Asyikeen Ab Mutalib Yi Deng An-Ju Hsueh Koki Kariya Toshiaki Kurihara Hiroaki Suzuki 《Electroanalysis》2021,33(10):2123-2127
The interfacial potential difference on the surface of bipolar electrodes was controlled by placing Ag/AgCl on part of the electrode. Oxygen reduction on the cathodic pole was coupled with an electrochemiluminescence (ECL) reaction on the anodic pole. In an open bipolar system, the ECL intensity depended on the location of Ag/AgCl and the concentration of Cl− ions. A current flowed through Ag/AgCl and the ratio of currents generated at the anodic and cathodic poles was affected by the position of Ag/AgCl. Further, the effect of Ag/AgCl placement was also demonstrated in a closed bipolar system using hydrogen peroxide (H2O2) and glucose as analytes. Ag/AgCl was also effective in adjusting the sensitivity to these analytes to achieve the best performance. This method of interfacial potential control is expected to contribute toward the development of reliable sensing devices and applications such as redox cycling, which require precise potential control. 相似文献
234.
We show the bursting process of dioleoylphosphatidylcholine (DOPC) liposomes in response to the addition of acetonitrile, a small toxic molecule widely used in the fields of chemistry and industry. The percentage of destroyed liposomes is reduced upon decreasing the acetonitrile fraction in the aqueous solution and vesicle bursting is not observed at volume ratios of 4:6 and below. This indicates that a high fraction of acetonitrile causes the bursting of liposomes, and it is proposed that this occurs through insertion of the molecules into outer leaflet of the lipid bilayer. The elapsed time between initial addition of acetonitrile and liposome bursting at each vesicle is also measured and demonstrated to be dependent on the volume fraction of acetonitrile and the vesicle size. 相似文献
235.
Guoqing Li Hitoshi Saito Shunji Ishio Toshiyuki Shima Koki Takanashi 《Journal of magnetism and magnetic materials》2006
Anomalous magnetization processes and non-symmetrical domain wall displacements in the minor loop of L10 FePt particulate films were investigated by magnetization measurements and in situ magnetic force microscopy. Magnetization (M) decreases dramatically on increasing the magnetic field to ∼3 kOe after which M becomes small and constant in the range of 5–20 kOe as observed in the successive measurement of minor loops. The domain wall displacement is non-symmetrical with respect to the field direction. The anomalous magnetization behavior was attributed to the non-symmetrical domain wall displacement and large magnetic field required for domain wall nucleation. Energy calculations from modeling suggest that non-symmetrical domain wall displacement is caused by the existence of metastable domains in which the domain edges are stuck to the particle boundaries. 相似文献
236.
Kunio Kimura Toshiyuki Horii Yuhiko Yamashita 《Journal of polymer science. Part A, Polymer chemistry》2003,41(21):3275-3282
Poly(p‐oxybenzoyl) (POB) crystals were prepared with the reaction‐induced crystallization of oligomers during the direct polycondensation of p‐hydroxybenzoic acid (HBA) with p‐toluenesulfonyl chloride (TsCl) and N,N‐dimethylformamide in pyridine. Sheaflike lozenge‐shaped POB crystals were obtained, of which the longer diagonal was 7.0–8.0 μm. The influence of the polymerization condition on the morphology was examined to optimize the preparative condition for the crystals exhibiting the clearest habit, and the favorable condition was determined as the molar ratio of TsCl to HBA of 1.3 and polymerization concentration of 3.0%. The crystals possessed extremely high crystallinity and outstanding thermal stability. The formation mechanism of the crystal was proposed as follows. When the number‐average degree of polymerization of the oligomers exceeded a critical value of about 4, they were precipitated to form the hexagonal lamellae. The crystals were grown very quickly to lozenge‐shaped crystal through screw dislocation with the continuous precipitation of oligomers from the solution. Finally, the further polymerization occurred in the precipitated crystal with developing polymer‐chain packing. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3275–3282, 2003 相似文献
237.
Itoh T Urita K Bekyarova E Arai M Yudasaka M Iijima S Ohba T Kaneko K Kanoh H 《Journal of colloid and interface science》2008,322(1):209-214
The nanoporosities and catalytic activities of Pd nanoparticles dispersed on single wall carbon nanohorns (Pd-SWCNHs) and oxidized single wall carbon nanohorns (Pd-ox-SWCNHs) were examined. A transmission electron microscopy (TEM) observation indicated that Pd nanoparticles of 2-3 nm size were highly dispersed on both the SWCNHs. X-ray photoelectron spectra and N2 adsorption isotherms at 77 K illustrated the differences in the deposition process mechanisms of the Pd-SWCNHs and Pd-ox-SWCNHs; the deposition process depended on the surface functional groups. The supercritical H2 adsorption isotherms at 77 K suggested the relationships between the interaction of Pd-SWCNHs and Pd-ox-SWCNHs with H2 and the catalytic activities for a water formation reaction in a gas phase at 273 or 298 K. The catalytic activity measurement and TEM observation of the catalysts after the reactions demonstrated that the Pd-SWCNHs and Pd-ox-SWCNHs are promising catalysts. 相似文献
238.
Enayati-Rad A Narduzzo A Rullier-Albenque F Horii S Hussey NE 《Physical review letters》2007,99(13):136402
The anisotropic resistivity of PrBa(2)Cu(4)O(8) has been measured as a function of electron irradiation fluence. Localization effects are observed for extremely small amounts of disorder corresponding to electron mean free paths of order 100 unit cells. Estimates of the localization corrections suggest that this anomalous localization threshold heralds a crossover to a ground state with pronounced one-dimensional character in which conduction electrons become confined to a small cluster of chains. 相似文献
239.
M. Haruta T. Sueyoshi T. Fujiyoshi M. Mukaida H. Kai K. Matsumoto P. Mele T. Maeda S. Horii 《Physica C: Superconductivity and its Applications》2011,471(21-22):944-946
Irreversibility lines and distributions of local critical current density (Jcl) based on the percolation transition model were affected by the growth temperature (Ts) in 3.5 wt.%-BaNb2O6-doped ErBa2Cu3Oy thin films. The vortex-Bose-glass-like state appeared by the introduction of nano-rods, and this vortex state was affected by Ts. The shape and width of the Jcl distribution strongly depended on Ts. These results are probably caused by variations of the density and the growth direction for nano-rods reflecting Ts. The growth temperature is an important factor to achieve higher critical current properties under magnetic fields for coated conductors of rare-earth-based cuprates with nano-rods. 相似文献
240.
Seiichi Tokura Koki Itoyama Norio Nishi Shin-Ichiro Nishimura Ikuo Saiki Ichiro Azuma Nishimura 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):1701-1718
The highest antithrombogenic activity was achieved by the N- and O-sulfation of partially N-deacetylated (70%) 6-O-carboxymethyl (0.60)-chitin (SCM-DAC-70) among various modified chitin derivatives. But a O-sulfated 6-O-carobxymethyl-chitin (SCM-chitin) was a quite in- ert heparinoid for the inhibition of blood clotting. It was also suggested that the distribution of N-sulfate and N-acetyl groups on the C-2 position of glucosamine residue might be essential to the selective adsorption of SCM-DAC-70 to antithrombin-III (AT-III) to inhibit thrombin activity. Kinetic evaluations demonstrated the noncompetitive inhibition of thrombin activity by SCM-DAC-70 and competitive inhibition of throm- bin by SCM-DAC-70-AT-III complex. We were unable to find such a specific inhibition by the SCM-DAC-70 complex with blood clotting factors other than AT-III. SCM-chitin was found to inhibit the metasta- sis of cancer cells at about 80–85% without any side effect different from those of heparin. It was suggested that the inhibition of metastasis of B16-BL6 melanoma cells was achieved by bifunctional inhibitions for heparanase and type IV collagenase without growth inhibition of cancer cells. 相似文献