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141.
Susan MA Noda A Mitsushima S Watanabe M 《Chemical communications (Cambridge, England)》2003,(8):938-939
Novel Br?nsted acid-base ionic liquids, derived from a simple combination of a wide variety of organic amines with bis(trifluoromethanesulfonyl) amide are electroactive for H2 oxidation and O2 reduction at a Pt electrode under non-humidifying conditions, which shows the prospect of the use of protic ionic liquids as new materials for anhydrous proton conductors at elevated temperatures. 相似文献
142.
Direct evidence for the plant origin of Brazilian propolis by the observation of honeybee behavior and phytochemical analysis 总被引:10,自引:0,他引:10
Kumazawa S Yoneda M Shibata I Kanaeda J Hamasaka T Nakayama T 《Chemical & pharmaceutical bulletin》2003,51(6):740-742
To identify the plant origin of Brazilian propolis directly, we observed the behavior of honeybees in Minas Gerais State of Brazil. Honeybee workers bit and chewed leaves of the plant, Baccharis dracunculifolia, packed the material into their pollen basket, brought it back to their nest, and used it as propolis. We collected the leaves of B. dracunculifolia and propolis, and compared their constituents by liquid chromatography-mass spectrometry (LC/MS) analysis. There was no difference between the chemical constituents of the ethanol extracts of B. dracunculifolia and those of propolis. This indicates directly that the plant origin of Brazilian propolis is B. dracunculifolia. 相似文献
143.
Nanocopying of individual DNA strands and formation of the corresponding surface pattern of titania nanotube 总被引:1,自引:0,他引:1
Fujikawa S Takaki R Kunitake T 《Langmuir : the ACS journal of surfaces and colloids》2005,21(19):8899-8904
Titania nanotube was prepared by nanocopying of the individual DNA double strand as template. DNA was first spread on a solid substrate, and its molecular surface was coated with an ultrathin titania layer by 3 cycles of the surface sol-gel process. Fluorescence microscopic images before and after titania coating of the DNA/YOYO-1 complex were essentially identical, showing that the titania coating did not change the chemical properties of the complex. Titania coating effectively prohibited chemical degradation of titania-coated DNA with DNase I and physically separated the DNA strand from the surrounding environment with an ultrathin titania barrier. The morphology of the DNA strand was preserved, as confirmed by microscopic and spectroscopic observations. The presence of the hollow (tubular) structure was confirmed by a silver staining experiment coupled with scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDX) analysis. The present finding shows the effectiveness of nanocopying of the individual DNA strand. 相似文献
144.
By measuring the very low energy photoemission spectra of the CO/Cu(001) surface with a high resolution, we have found the energy loss components due to inelastic scattering of electrons near the Fermi level by the CO vibrational modes. The main energy loss structure appears as a step at 254 meV below the Fermi edge for 12C16O. An isotope shift of the step to 240 meV was observed when 13C18O was adsorbed. This observation confirms that this step arises from the energy loss of photoelectrons near the Fermi level through the excitation of the C-O stretching mode. 相似文献
145.
Shigenori Egusa Keizo Makuuchi 《Journal of polymer science. Part A, Polymer chemistry》1982,20(3):863-874
The emulsion Copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using 60Co γ-rays as initiator and sodium do-decylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped-flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles. 相似文献
146.
A novel flow-injection spectrophotometric method has been developed for the determination of manganese(II) at sub-nanogram/ml levels. The method is based on its catalytic effect on the oxidation of N,N′-bis(2-hydroxy-3-sulfopropyl)tolidine (HSPT) by periodate. The catalytic effect of manganese(II) was enhanced by the presence of 2,2′-bipyridine as an activator. By monitoring the change in absorbance of the oxidation product of HSPT at 670 nm, manganese(II) ranging 0.02-3.0 ng ml−1 could be determined with the relative standard deviations of less than 2%. The interfering ions were effectively suppressed by the addition of 2,2′-iminodiethanol and citric acid. The proposed method is directly applicable to the determination of manganese in lake and river water samples. 相似文献
147.
Shigenori Yanagi 《Mathematical Methods in the Applied Sciences》1993,16(9):609-624
We study the p-system with viscosity given by vt ? ux = 0, ut + p(v)x = (k(v)ux)x + f(∫ vdx, t), with the initial and the boundary conditions (v(x, 0), u(x,0)) = (v0, u0(x)), u(0,t) = u(X,t) = 0. To describe the motion of the fluid more realistically, many equations of state, namely the function p(v) have been proposed. In this paper, we adopt Planck's equation, which is defined only for v > b(> 0) and not a monotonic function of v, and prove the global existence of the smooth solution. The essential point of the proof is to obtain the bound of v of the form b < h(T) ? v(x, t) ? H(T) < ∞ for some constants h(T) and H(T). 相似文献
148.
Shigenori Kagiyama Akihiro Nakamura Toshihiro Omodaka 《Zeitschrift fur Physik C Particles and Fields》1992,56(4):557-560
We propose dibaryon stars on the base of the compressible bag model, in which a hadron bag responds microscopic thermal pressure of the other bags and the volume exclusion effect is considered. In general, a free bosonic point-particle matter has no pressure at zero temperature, but a condensed bosonic bag matter is able to have a finite pressure because of both the compressibility and the volume exclusion effects. We will show that the condensed dibaryon matter not only produce a very soft equation of state but can also bring the 1.44M
mass star. 相似文献
149.
Masakatsu Ueno Satoshi Ueyama Shigenori Hashimoto Noriaki Tsuchihashi Kazuyasu Ibuki 《Journal of solution chemistry》2004,33(6-7):827-846
NMR spin-lattice relaxation time (T 1) measurements were performed for 14N of acetonitrile in acetonitrile (CH3CN)—H2O mixtures and for 2H of heavy water in CH3CN—D2O mixtures at 30°C up to 294.2 MPa together with those for 2H in CH3CN—D2O mixtures at 10 and 20°C under atmospheric pressure over the whole composition range of the mixtures. IR absorption spectra for CH3CN—H2O and CH3CN—10 mol% HDO/D2O mixtures were obtained at 30°C under atmospheric pressure. Densities and viscosities of CH3CN—H2O mixtures were also measured under high pressure. The rotational correlation times for D2O [τ c (D)] and acetonitrile [τ c (N)] were determined from T 1 measurements. Under atmospheric pressure, τ c (D) exhibits a small maximum around 10 mol% of acetonitrile at each temperature, and the maximum position is almost independent of temperature. These results suggest that the dipole–dipole interaction between acetonitrile and water molecules plays an important role in determining the rotational motion of water molecules in the mixtures. This is supported by the variation of the peak for the bending vibration of water molecules with composition. The decreases in τ c (D) and τ c (N) at higher acetonitrile contents are ascribed to the formation of acetonitrile dimer, trimer, and oligomer aggregates. Except for τ c (D) in the water-rich region, the pressure coefficients of τ c (D) and τ c (N) are positive which is understood as a simple compression effect. Furthermore, the composition of mixture at which τ c (D) and τ c (N) show a maximum shifted to higher acetonitrile content with increasing pressure. These results are discussed in terms of the pressure effect on the equilibria of acetonitrile monomers with the aggregates of acetonitrile in the mixtures. 相似文献
150.
Shogo Miyoshi Shigenori Onuma Hiroshige Matsumoto Tatsuya Kawada Harumi Yokokawa 《Journal of solid state chemistry》2004,177(11):4112-4118
The single-phase region of La1−xSrxCrO3 (x=0.1, 0.2, 0.3) was precisely determined as a function of temperature, PO2 and Sr content. The powders with the nominal composition of La1−xSrxCrO3 were equilibrated under various conditions, and then identified by XRD analyses. To confirm the equilibration, two independent experiments were performed for each composition observing (i) the precipitation of the second phase from a single-phase solid solution, and (ii) the formation of the single phase from the constituent oxides. Two kinds of second phases, SrCrO4 and an unknown phase, were observed depending on the conditions. The second phases tended to appear at low temperature, in high PO2 and with a large Sr content. The single-phase regions obtained via the two equilibration routes were in good agreement with each other. The thermodynamic calculations on the supposition of ideality of the solid solution essentially reproduced the experimental results. When this material is used as the interconnects of solid oxide fuel cells, much attention should be paid to its relatively narrow solubility range of Sr; for example, the solubility limit is approximately 0.1 under a typical cathode-side condition (1273 K, air). 相似文献