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811.
812.
In laser frequency stabilization using an atomic or molecular beam reference, systematic errors could be introduced by the non-orthogonality of the laser light and the direction of the atomic beam. These effects are computed theoretically and numerical values are obtained for various degrees of non-orthogonality. 相似文献
813.
Atsushi Hirano Yutaka Maeda Prof. Dr. Takeshi Akasaka Prof. Dr. Kentaro Shiraki Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9905-9910
Carbon nanotubes (CNTs) are anticipated as an important new material for use in nanotechnology applications because of their excellent mechanical and electrical properties. For their development, a highly stable dispersion of debundled CNTs is indispensable. Herein we present a new method to enhance dispersibility of single‐walled carbon nanotubes (SWNTs) with proteins using alcohols as co‐solvents. Addition of fluoroalcohols in solution increased the SWNT dispersion by more than one order of magnitude without protein denaturation. Enhancement of SWNT dispersion through addition of alcohols was attributed to the decreased hydrophobic interaction among SWNTs. This novel approach enables us to produce biofunctional CNTs such as one‐dimensional nanobiosensors and drug carriers that can penetrate cells. 相似文献
814.
Anatase-type nanoparticles ScXTi1−2XNbXO2 with wide solid solution range (X=0-0.35) were hydrothermally formed at 180 °C for 5 h. The lattice parameters a0 and c0, and the optical band gap of anatase gradually and linearly increased with the increase of the content of niobium and scandium from X=0 to 0.35. Their photocatalytic activity and adsorptivity by the measurement of the concentration of methylene blue (MB) that remained in the solution in the dark or under UV-light irradiation were evaluated. The anatase phase existed stably up to 900 °C for the samples with X=0.25-0.30 and 750 °C for that with X=0.35 during heat treatment in air. The phase with α-PbO2 structure and the rutile phases coexisted in the samples with X=0.25-0.30 after heated at temperatures above 900-950 °C. The α-PbO2 structure having composition ScTiNbO6 with possibly some cation order similar to that seen in wolframite existed as almost completely single phase after heat treatment at temperatures 900-1500 °C through phase transformation from anatase-type ScTiNbO6. 相似文献
815.
816.
Dr. Atsushi Hirano Dr. Takeshi Tanaka Dr. Hiromichi Kataura Dr. Tomoshi Kameda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4922-4930
Charged peptides and proteins disperse single‐wall carbon nanotubes (SWCNTs) in aqueous solutions. However, little is known about the role of their side chains in their interactions with SWCNTs. Homopolypeptide–SWCNT systems are ideal for investigating the mechanisms of such interactions. In this study, we demonstrate that SWCNTs are individually dispersed by poly‐L ‐arginine (PLA). The debundled SWCNTs exhibited a distinct fluorescence. The dispersibility of SWCNTs with PLA was greater than that of SWCNTs with poly‐L ‐lysine (PLL). Molecular dynamics simulations suggest that the side chains of PLA have stronger interactions with the sidewalls of SWCNTs compared with those of PLL. The guanidinium group at the end of the side chain of an arginine residue plays an important role in the interaction with SWCNTs, likely through hydrophobic, van der Waals, and π–π interactions. PLA can be useful as a tool for the dispersion of SWCNTs and can be used to non‐covalently anchor materials to SWCNTs with strong binding. 相似文献
817.
A three-dimensional photovisco-elasto-plastic model considering the strain rate effect was investigated by the scattered-light
method using polyester as a model material. To examine the mechanical and optical properties of the material, tension and
torsion tests were carried out on cylindrical specimens under various strain rates at 30°C. The effects of strain rate on
the stress-strain relation and scattered-light fringe appearance were evaluated. The equivalent shearing stress-strain relation
can be approximated by the Ramberg-Osgood equation with rate-dependent modulus and yield stress. The fringe gradient, when
normalized by a rate-dependent yield gradient, can be related to an equivalent strain in the same form regardless of the strain
rate. The strain rate can be evaluated from the measurement of the rate of increase of the fringe gradient. Hence, the relation
between the fringe gradient and its rate of increase was derived as a function of strain rate. Finally, a method is proposed
for the estimation of the visco-elasto-plastic stress and strain in a three-dimensional specimen from the measurement of only
the fringe gradient and its rate of increase. The method was successfully applied not only to uniaxial tension but also to
pure torsion. 相似文献
818.
Effects of water and alcohol on the formation of inclusion complexes of d-limonene and cyclodextrins
Takeshi Furuta Hidefumi Yoshii Atsuyuki Miyamoto Akira Yasunishi Hiroshi Hirano 《Supramolecular chemistry》2013,25(3-4):321-325
Abstract Systematic studies have been carried out on the role of water and alcohol in the formation of inclusion complexes between d-limonene and α-, β- and γ-cyclodextrin (CD) by a micro-aqueous method. The inclusion complex was barely formed at zero water content for all CDs. Above the specific water content for each CD, formation of the inclusion complex correlated well with an equation which was derived on the autocatalytic assumption for the inclusion phenomenon. The inclusion complex correlated well with an equation which was derived on the autocatalytic assumption for the inclusion phrnomenon. The minimum water content, which was defined as 1% of the maximum concentration of the inclusion complex formed, coincided with the number of water molecules inside the cavity of the CD. In the presence of ethanol, a significant amount of the inclusion complex was formed for β- and γ-CD/limonene systems, particularly at lower moisture content. However, for α-CD the inclusion fraction decreased significantly in the presence of ethanol. This means that ethanol inhibits the formation of the inclusion complex between x-CD and d-limonene. For other linear alcohols, the formation of the inclusion complex between d-limonene and β-CD increased with decreasing alkyl chain length. This suggests that the more hydrophilic and the smaller (in molecular size) the alcohol is, the more enhanced is the inclusion of d-limonene to β-CD. 相似文献
819.
Tomohiko Hirano Shinya Kitagawa Hajime Ohtani Takehiko Kinoshita Yuzo Ishigaki Nobuyuki Shibata Susumu Nii 《Analytical and bioanalytical chemistry》2013,405(25):8319-8326
A method for evaluating the interactions between metal ions and nonionic surfactants in aqueous solutions containing high-concentration HCl, using gas pressure-driven low-pressure high-performance liquid chromatography (LP-HPLC) as a highly acid-resistant HPLC system, was developed. To construct the LP-HPLC for this purpose, poly(styrene-co-divinylbenzene)-based low-flow-resistance monolithic columns tolerant to highly acidic conditions were prepared using low-conversion thermal polymerization. Thermal polymerization at 65 °C for 1.5 h (monomer conversions, 33 % for styrene and 59 % for divinylbenzene) allowed preparation of a column with both high separation efficiency (around 60,000 plates m?1 for alkylbenzenes) and a quite low back pressure of 0.14 MPa at a linear flow rate of 1 mm s?1 (2.8?×?10?13 m2 in permeability). The base column prepared under the above conditions was coated with a nonionic surfactant, polyoxyethylene nonylphenyl ether (PONPE, average oxyethylene unit numbers (n)?=?3, 7.5, 15, and 20), and used for evaluation of the interactions between PONPEs and metal ions in 6 M HCl. The interactions between PONPEs and Au(III), Ga(III), Fe(III), Zn(II), and Cu(II) were successfully evaluated using both breakthrough and chromatographic methods. Furthermore, a study of the effect of the polyoxyethylene (POE) chain length revealed that the use of PONPE with the longer POE moiety enhanced the magnitude of the interaction together with the increase in the amount of oxyethylene (OE) units coated on the monolith. Moreover, the interactions of metal ions with a single OE unit were almost constant in the range of n?=?7.5–20, whereas the suppression of the interaction between Au(III) with the shortest PONPE chain (n?=?3) was also observed. Figure
Acid-resistive gas pressure-driven low-pressure high-performance liquid chromatography was developed and applied to the evaluation of interactions between metal ions and nonionic surfactants in high-concentration HCl, in particular for the effect of polyoxyethylene length on the interaction. 相似文献
820.
Keisuke Hirano Hitoshi Yamato Kazuhiko Kunimoto Masaki Ohwa 《Journal of Electroanalytical Chemistry》2001,510(1-2)
Novel indophenol derivatives were synthesized and characterized electrochemically with respect to their abilities to act as electron-transfer mediators for lactate oxidase. These compounds showed suitable redox potentials and high second-order rate constants, kmed, in solution for electron-transfer from the reduced enzyme. A lactate sensor using these derivatives demonstrated high sensitivity and good substrate selectivity. This sensor could also achieve excellent durability which retained more than 70% residual activity and good linearity in the range from 0 to 16 mM lactate concentration even after 10 days. 相似文献