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131.
132.
Junichiro Otomo Hitoshi Shigeoka Hiroshi Takahashi 《Journal of Physics and Chemistry of Solids》2005,66(1):21-30
Proton conduction and crystal structure in CsHSO4/SiO2 composite composed of polycrystalline CsHSO4 and mesoporous silica particles were investigated based on conductivity measurement and characterizations using Raman spectroscopy, XRD, and differential thermal analysis. The conductivity of pure CsHSO4 abruptly changes at around 414 K (superprotonic phase transition), being accompanied with the structural transformation from a monoclinic phase to a tetragonal phase, while the conductivity of CsHSO4/SiO2 composite is significantly larger by over three orders of magnitude than that of pure CsHSO4 below the critical temperature of the superprotonic phase transition (353-414 K). Raman spectroscopy and XRD indicate that this remarkable conductivity-enhancement in the composite is not due to the stabilization of the tetragonal phase (superprotonic phase) below its critical temperature. The line-broadening of the internal modes in the Raman spectra suggests that the rapid reorientational motion of the HSO4− ion, which leads to superprotonic conduction, is induced in the composite even below the critical temperature. The reorientational motion of the HSO4− ion below the critical temperature will occur at the interfacial phase which is structurally disordered and forms between CsHSO4 and SiO2 in the mesopores and/or on the surfaces of silica particles. Proton transfer will be accelerated via the interfacial conduction-pathway in the composite. 相似文献
133.
Tsunehisa Hirashita Yusuke Daikoku Hitoshi Osaki Mamiko Ogura Shuki Araki 《Tetrahedron letters》2008,49(37):5411-5413
Methylenecyclopropanes carrying a hydroxymethyl group at the ring underwent stereoselective allylindation with allylindium sesquiiodide to afford the allylated products, in which the allyl group was delivered at the external sp2 carbon via cyclopropylindium intermediates. The reaction of ethyl 2-cyclopropylideneacetate and triallylindium afforded the 1,4-adduct along with dimeric products. 相似文献
134.
Magnetophoretic velocimetry is a novel technique to measure the magnetic susceptibility of a single microparticle. This technique could be applied to study the interfacial adsorption equilibria of a paramagnetic dysprosium(III) ion with capric, lauric or stearic acid for a single 2-fluorotoluene microdroplet. The observed magnetic susceptibility of the micro-organic droplets was reciprocally proportional to its radius in each case. From the proportional constant, the interfacial concentration of Dy(III) was determined. Furthermore, the dependences of the interfacial concentration on the initial Dy(III) concentration and pH were examined in order to analyze the adsorption equilibrium. Finally, the saturated interfacial concentration and the interfacial adsorption constant at the infinite dilution of Dy(III)-laurate complex were evaluated as 4.8 x 10(-10) mol cm(-2) and 3.4 x 10(-2) dm, respectively. 相似文献
135.
Noriki Kutsumura Kota Shibuya Hitoshi Yamaguchi Takao Saito 《Tetrahedron letters》2017,58(43):4099-4102
Regioselective elimination of a vicinal bis-triflate having an adjacent ether oxygen functional group has been developed. Considered in the context of our studies of the regioselective elimination of vicinal dibromide, the key to the mechanism involves the electron-withdrawing inductive effect of the neighboring oxygen functional group. Aliphatic vinyl triflate was shown to be effective in Suzuki–Miyaura cross coupling compared with corresponding aliphatic vinyl bromide. 相似文献
136.
Hiroaki Aizawa Ken Hatano Hitoshi Saeki Nobuaki Honsho Tetsuo Koyama Koji Matsuoka Daiyo Terunuma 《Tetrahedron letters》2010,51(12):1545-6442
A new compound having a 2,3,4,5-tetraphenylsilole derivative on the center silicon of Dumbbell(1)6Gb3; Silole-Dumbbell(1)6Gb3 (1) was previously reported. It was found that 1 exhibited strongly increased fluorescence both in water and in a 96% acetone/water mixed solvent. The physical behavior of 1 in water and in the 96% acetone/water mixed solvent was investigated, and analyses including fluorescence quantum yields, dynamic-light-scattering (DLS), atomic-force-microscopy (AFM), and fluorescence microscopy were carried out. It was clarified that 1 dynamically formed different types of aggregates in water and in higher acetone concentrations to yield high aggregation-induced emission (AIE) effects due to the formation of micelle-like particles in water and inversion-type micelles in the acetone/water mixed solvent, respectively. 相似文献
137.
Eiji Hashimoto Yuichi Seshimo Keita Sasanuma Yuichiro Aoki Hitoshi Kanazawa Yuji Ike Seiji Kojima 《Journal of Thermal Analysis and Calorimetry》2010,99(1):45-50
The fragility of ethylene glycol and glucose aqueous solution systems has been investigated by temperature-modulated differential
scanning calorimetry (TMDSC). The frequency and temperature dependences of complex specific heat have been observed in the
vicinity of a glass-transition temperature T
g
. It is shown that the value of the fragility index m can be determined from the temperature dependence of the α-relaxation times observed by TMDSC. We have also studied the elastic
properties of these aqueous solutions by micro-Brillouin scattering, and determined these relaxation times of elastic properties
in the gigahertz range. 相似文献
138.
Kumi Y. Inoue Kosuke Ino Hitoshi Shiku Tomokazu Matsue 《Electrochemistry communications》2010,12(8):1066-1069
We have developed a zymogen-based electrochemical sensor. Zymogen is an inactive enzyme precursor (proenzyme) and it is necessary to transform it biochemically (e.g., by hydrolysis and conformational change) to make it an active enzyme. In this study, we demonstrated the detection of endotoxin by using recombinant Factor C (rFC), which is a protease zymogen activated by endotoxin binding. The activated rFC hydrolyzes a synthetic substrate of Boc-Val-Pro-Arg-p-nitroanilnide to generate an electrochemical active compound, p-nitroaniline (pNA). The liberated pNA was detected by differential pulse voltammetry at –0.75 V. By using this electrochemical process, 5000 endotoxin units (EU) L?1 and 1000 EU L?1 were detected in a Tris-Ac buffer with a pH of 7.5 at 37 °C for reaction times of 1 h and 3 h, respectively. The concept of zymogen-based electrochemical sensors is expected to lead to the development of new biosensors. 相似文献
139.
Tanaka H Sudo M Hirata M Etoh H Sato M Yamaguchi R Sakai E Chen IS Fukai T 《Natural product communications》2010,5(11):1781-1784
A new biisoflavonoid, biseryvarin A (1a), together with two known compounds were isolated from the roots of Erythrina variegata. The structure of biseryvarin A was established on the basis of spectroscopic evidence. Biseryvarin A is the first dimeric isoflavonoid possessing isoprenoid groups from the genus Erythrina. Biseryvarin A showed low activity against methicillin-resistant Staphylococcus aureus (MRSA). 相似文献
140.
Some important classes of optimization problems originating from the optimal design of semiconductor memories such as SRAM,
aiming at boosting the yield rate, are studied. New optimization methods for the classes based on a symbolic algorithm called
quantifier elimination, combined with numerical computation, are proposed. The total efficiency of the design process is improved
by reducing the number of numerical yield-rate evaluations. In addition, useful information such as the explicit relations
among design variables, objective functions, and the yield rate, is provided. 相似文献