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81.
Kiyoharu Tadanaga Akira Miyata Daisuke Ando Naoko Yamaguchi Masahiro Tatsumisago 《Journal of Sol-Gel Science and Technology》2012,62(1):111-116
Using hot water treatment of sol–gel derived precursor gel films, Co–Al and Ni–Al layered double hydroxide (LDH) thin films
were prepared. The precursor gel films of Al2O3–CoO or Al2O3–NiO were prepared from cobalt or nickel nitrates and aluminum tri-sec-butoxide using the sol–gel method. Then, the precursor gel films were immersed in a NaOH aqueous solution of 100 °C. Nanocrystallites
of Co–Al and Ni–Al LDH were precipitated with the hot water treatment with NaOH solution. The largest amounts of nanocrystals
were obtained with a solution of pH = 10 for Co–Al LDH, and with that of pH = 9 for Ni–Al LDH. X-ray diffraction measurements
confirmed that this process formed CO3
2− intercalated LDHs. Both Co–Al and Ni–Al LDH thin films were confirmed to work as electrodes for electrochemical devices by
cyclic voltammogram measurements. 相似文献
82.
Daisuke Suzuki Tomoyo Yamagata Koji Horigome Kiyoshi Shibata Akira Tsuchida Tsuneo Okubo 《Colloid and polymer science》2012,290(2):107-117
Influence of the gel size on the morphology, phase diagram, and reflection spectroscopy of the colloidal crystals of thermo-sensitive
gel spheres, poly (N-isopropylacrylamide) (pNIPAm), was discussed by adding the data of two gel samples of pNIPAm(400–5) and pNIPAm(600–5) of
412 nm (at 25 °C) and 220 nm (at 45 °C) and of 517 nm (at 20 °C) and 294 nm (at 45 °C), respectively. Colloidal single crystals
formed, but not so large compared with the giant crystals of small pNIPAm gels reported previously. The suspensions even with
ion-exchange resins were turbid and hard to observe the single crystals clearly with the naked eyes as gel size increased.
The critical concentration of melting decreased sharply as the suspensions were deionized with coexistence of the mixtures
of cation- and anion-exchange resins. The critical concentration increased as the gel size increased and/or dispersion temperature
increased. Density of the gel spheres increased as their size increased. These results demonstrated that the colloidal crystallization
takes place by the extended electrical double layers formed around the gel spheres in addition of the excluded volume effect of the gels. Contribution of the electrical double layers on the crystallization increased sharply as temperature increased
and gel concentration decreased, respectively. The contribution also increased slightly as sphere size increased, when comparison
was made at the same gel concentration in wt.%. The present work clarified that the colloidal interfaces, which are inevitable
for the formation of the electrical double layers, are formed between the water phase and gel spheres, though the gel spheres
contain a lot of water molecules at the inner sphere region. 相似文献
83.
84.
Tatsunori Iwamura Takashi Ichikawa Hiroshi Shimizu Tadashi Kataoka 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):471-472
Abstract Reactions of thiazolo[3,2-b]-1,2,4-triazolium N-methylides with electron-deficient acetylenes gave the thiazole ring-opened products as a mixture of the E-and Z-isomers. In contrast, the N-phenacylides reacted with dimethyl acetylenedicarboxylate to give the thiobenzoates together with the thiazole ring-opened products. The mechanism for formation of these compounds is described. 相似文献
85.
86.
Chi-Huey Wong Randall L. Halcomb Yoshitaka Ichikawa Tetsuya Kajimoto 《Angewandte Chemie (International ed. in English)》1995,34(4):412-432
Carbohydrates on cell surfaces are information molecules. Although only seven or eight monosaccharides are commonly used as building blocks in mammalian systems, the multifunctionality of these monomers can lead to the assembly of an immense variety of complex structures. Millions of different tetrasaccharide structures, for example, can be constructed from this small number of building blocks, if branching, the stereochemistry of glycosidic linkages, and the modification of hydroxyl and amino groups are taken into consideration. Oligosaccharides therefore represent an effective class of biomolecules that code for a vast amount of information required in various biological recognition processes, such as intercellular communication, signal transduction, cell adhesion, infection, cell differentiation, development and metastasis. The pace of development of pharmaceuticals based on carbohydrates has, however, been slower than that based on other classes of biomolecules. Part of the reason is the lack of technologies for the study of complex carbohydrates. There is no method to amplify oligosaccharides for sequence analysis. There is no machine available for automated synthesis of oligosaccharides. In addition, the possibly poor bioavailability and difficulties in the large-scale synthesis of carbohydrates have undoubtedly contributed to this slow pace. The enzymatic and chemoenzymatic methods, especially those based on aldolases and glycosyltransferases, described here appear to be useful for the synthesis of mono- and oligosaccaharides and related molecules. Further advances in glycobiology will probably lead to the development of new technologies for the study of carbohydrate recognition and for the synthesis of bioactive carbohydrates and mimetics to control the recognition processes. 相似文献
87.
Hori R Furukawa D Yamamoto K Kutsumizu S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(24):7346-7350
Binary mixtures were prepared from an azobenzene derivative and a liquid-crystal (LC) compound that exhibits smectic?C (SmC) and bicontinuous cubic (Cub(bi)) LC phases. Reversible switching between the two phases in response to UV-light irradiation was observed. This light-driven SmC-to-Cub(bi) transition is the first example showing the increased dimensionality of molecular ordering with isomerization of azobenzenes (see figure). 相似文献
88.
Ion-exclusion/anion-exchange chromatography(IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH——form with basic eluent has been developed.The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase.This system is useful for simultaneous separation and determination of ammonium ion(NH+4),nitrite ion(NO-2),and nitrate ion(NO-3) in water samples.The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column.In this study,several separation columns,which consisted of different particle sizes,different functional groups and different anion-exchange capacities,were compared.As the results,the separation column with the smaller anion-exchange capacity(TSKgel Super IC-Anion) showed well-resolved separation of cations and anions.In the optimization of the basic eluent,lithium hydroxide(LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L,considering the resolution of analyte ions and the whole retention times.In the optimal conditions,the relative standard deviations of the peak areas and the retention times of NH+4,NO-2,and NO-3 ranged 1.28%-3.57% and 0.54%-1.55%,respectively.The limits of detection at signal-to-noise of 3 were 4.10 μmol/L for NH+4,1.87 μmol/L for NO-2 and 2.83 μmol/L for NO-3. 相似文献
89.
Gold nanoparticles located at the interface of anatase/rutile TiO2 particles as active plasmonic photocatalysts for aerobic oxidation 总被引:1,自引:0,他引:1
Tsukamoto D Shiraishi Y Sugano Y Ichikawa S Tanaka S Hirai T 《Journal of the American Chemical Society》2012,134(14):6309-6315
Visible-light irradiation (λ > 450 nm) of gold nanoparticles loaded on a mixture of anatase/rutile TiO(2) particles (Degussa, P25) promotes efficient aerobic oxidation at room temperature. The photocatalytic activity critically depends on the catalyst architecture: Au particles with <5 nm diameter located at the interface of anatase/rutile TiO(2) particles behave as the active sites for reaction. This photocatalysis is promoted via plasmon activation of the Au particles by visible light followed by consecutive electron transfer in the Au/rutile/anatase contact site. The activated Au particles transfer their conduction electrons to rutile and then to adjacent anatase TiO(2). This catalyzes the oxidation of substrates by the positively charged Au particles along with reduction of O(2) by the conduction band electrons on the surface of anatase TiO(2). This plasmonic photocatalysis is successfully promoted by sunlight exposure and enables efficient and selective aerobic oxidation of alcohols at ambient temperature. 相似文献
90.
Taguchi S Ichikawa T Kato T Ohno H 《Chemical communications (Cambridge, England)》2012,48(43):5271-5273
A combination of a phosphonium-type-zwitterions-lithium bis(trifluoromethanesulfonyl)imide complex and a hydrophilic ammonium salt provides a nanosegregated liquid-crystalline matrix consisting of hydrophilic ionic liquid (IL) domains and hydrophobic IL domains. 相似文献