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131.
Naoyuki Ishida 《Colloids and surfaces. A, Physicochemical and engineering aspects》2007,300(3):293-299
Direct measurements of the interaction forces between a spherical silica particle and a small air bubble have been conducted in aqueous electrolyte solutions by using an atomic force microscope (AFM). The silica particle was hydrophobized with a silanating reagent, and the interaction forces were measured by using several particles with different surface hydrophobicities. In the measured force curves, a repulsive force was observed at large separation distances as the particle moved towards the bubble. The origin of the repulsive force was attributed to an electrostatic double-layer force because both the particle and bubble were negatively charged. After the repulsive force, an extremely long-range attractive force acted between the surfaces. These results indicate that the intervening thin water film between the particle and bubble rapidly collapsed, resulting in the particle penetrating the bubble.
The instability of the thin water film between the surfaces suggests the existence of an additional attractive force. By comparing the repulsive forces of the obtained force curves with the DLVO theory, the rupture thickness was estimated. The hydrophobicity of the particle did not significantly change the rupture thickness, whereas the pH of the solution is considered to be a critical factor. 相似文献
132.
Computational calculations of Becke's three-parameter hybrid method using the LYP correlation functional (B3LYP) have been performed on (B12H12)2− dodecaborane anions with different boron isotopic compositions. This was done in order to investigate isotopic dependence of vibrational spectral properties of B12 icosahedra, and for comparison of the optical vibrational properties of the icosahedral molecule with the characteristics of inter- or intra-icosahedral optical phonon vibrational modes in boron-rich crystals. 相似文献
133.
134.
Shunsuke Yanagi Akihisa Matsumoto Dr. Naoyuki Toriumi Yusuke Tanaka Dr. Kazunori Miyamoto Dr. Atsuya Muranaka Prof. Dr. Masanobu Uchiyama 《Angewandte Chemie (International ed. in English)》2023,62(11):e202218358
Activatable near-infrared (NIR) dyes responsive to external stimuli are used in medical and other applications. Here, we describe the design and synthesis of bench-stable 18π- and 20π-electron benzitetraazaporphyrins (BzTAPs) possessing redox-switchable NIR properties. X-Ray, NMR, and UV/Visible-NIR analyses revealed that 20π-electron BzTAP 1 exhibits NIR absorption and antiaromaticity with a paratropic ring-current, while 18π-electron BzTAP 2 shows weakly aromatic character with NIR inertness. Notably, the NIR-silent BzTAP 2 was readily converted to the NIR-active BzTAP 1 in the presence of mild reducing agents such as amine. The intense NIR absorption band of BzTAP 1 is in sharp contrast to the very weak absorption bands of previously reported antiaromatic porphyrinoids. Molecular orbital analysis revealed that symmetry-lowering perturbation of the 20π-electron porphyrinoid skeleton enables the HOMO–LUMO transition of 1 to be electric-dipole-allowed. BzTAPs are expected to be useful for constructing activatable NIR probes working in reductive environments. 相似文献
135.
Naoyuki Kotoku Aoi Ito Shunichi Shibuya Kanako Mizuno Aki Takeshima Masaki Nogata Motomasa Kobayashi 《Tetrahedron》2017,73(10):1342-1349
An improved method for synthesizing structurally simplified analogs of cortistatin A (1), a novel anti-angiogenic steroidal alkaloid from a marine sponge, was developed. In contrast to previous methods, step- and redox-economical synthesis was achieved using a known α-bromoketone as the starting material. The structure-activity relationship study revealed that the isoquinoline portion was strictly recognized by the target molecule. Surprisingly, the introduction of the acetamide moiety on the A-ring structure dramatically enhanced the selective antiproliferative activity against endothelial cells. This new method can be easily applied to gram-scale synthesis and enabled us to prepare various analogs, which were focused on the participation of the side chain and A-ring structure. 相似文献
136.
A new sensitive and selective resin spot test for nanogram quantities of molybdenum(Vl) with tiron is proposed. The limit of identification is 8 ng(1:5 · 106) after 1 hour standing. Vanadium(V), chromium(VI), uraniuni(lV), titanium (IV), palladiuin(II), platinum(lV), silver(I) and gold(III) interfere. Uranium(VI) (20 ng 1:2·106) can be detected similarly. 相似文献
137.
We give examples of the interior derivative blow-up solutions for the curvature evolution of capillary surfaces over a bounded domain in .
138.
Akinori Koukitu Naoyuki Takahashi Tetsuya Taki Hisashi Seki 《Journal of Crystal Growth》1997,170(1-4):306-311
A chemical equilibrium model is applied to the growth of the InxGa1−xN alloy grown by metalorganic vapor-phase epitaxy (MOVPE). The equilibrium partial pressures and the phase diagram of deposition are calculated for the InxGa1−xN alloy. The vapor-solid distribution relationship is discussed in comparison with the experimental data reported in the literature. It is shown that the solid composition of the InxGa1−xN alloy grown by MOVPE is thermodynamically controlled and that the incorporation of group III elements into the solid phase deviates from a linear function of the input mole ratio of the group III metalorganic sources under the conditions of high mole fraction of decomposed NH3 (high value of ), high temperature and low input V/III ratio. The origin of the deviation of the solid composition from the linear relation is also discussed. 相似文献
139.
Kazumasa Funabiki Naoyuki Sugiyama Ji-Ye Jin Yasutake Kato Masaki Matsui 《Journal of fluorine chemistry》2006,127(2):257-262
Four kinds of ring-fluorinated fluoresceins and sulfofluorescein from tetrafluororesorcinol and/or tetrafluorophthalic anhydride have been synthesized and the photochemical properties of the zinc oxide nanocrystalline electrode sensitized by the ring-fluorinated fluoresceins were investigated. 相似文献