Takeshi Hasegawa

京都大学

A novel measurement technique has been developed to simultaneously obtain polarized spectra of in-plane (IP) and out-of-plane (OP) vibrational modes in optically thin films deposited on a nonmetallic substrate without using a polarizer. These spectra correspond to the conventional infrared transmission and reflection−absorption (RA) spectra, respectively. It has been commonly believed that the mode-selective measurements require polarizers and a specific surface. In particular, the OP-mode measu

Perfluoroalkyl (R_f ) compounds have unique characters represented by a significantly high hydrophobic property, which often makes us consider that R_f groups should be interacted with each other via the 'hydrophobic interaction' as found for a normal hydrocarbon. Due to a similar intuitive and simplistic speculation, the R_f -specific material properties have long been enveloped in darkness for comprehensive understanding, which should lucidly be discussed within a

A long-time issue that thin films supported on a substrate with low refractive index cannot be subjected to multiple-angle incidence resolution spectrometry (MAIRS) has been resolved, and an advanced MAIRS technique has been developed. Infrared multiple-angle incidence resolution spectroscopy (IR MAIRS) is being recognized as a powerful spectroscopic tool for revealing molecular orientation in thin films or molecular adsorbates. MAIRS has been, however, employed with only IR spectroscopy thus fa

Abstract Perfluoroalkyl compounds are known to exhibit a hydrophobic character on the surface of the material, although the CF bond has a large dipole, which should make the molecular surface polar and hydrophilic. This inconsistency has long been a chemical matter to be solved. Herein, a stratified dipole‐arrays model is proposed: the molecular polar surface can be fully hidden by forming a two‐dimensional aggregate of perfluoroalkyl (R f ) groups; this aggregate is spontaneously induced by di

We have developed HTS cables using Bi-2212 round wires, which have high mechanical strength and an average J/sub c/ of 200 kA/cm/sup 2/ at 4.2 K in self-field. Four designs of cables were fabricated in this work and those tables could carry I/sub c/ values from 1 kA to 10 kA at 4.2 K and self-field depending on the number of strands. A 70m-long 20-strand Rutherford cable was successfully manufactured. Optimization of heat treatment conditions was effective to reduce I/sub c/ degradation observed

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared external reflection study of molecular orientation in thin Langmuir-Blodgett filmsTakeshi Hasegawa, Junzo Umemura, and Tohru TakenakaCite this: J. Phys. Chem. 1993, 97, 35, 9009–9012Publication Date (Print):September 1, 1993Publication History Published online1 May 2002Published inissue 1 September 1993https://pubs.acs.org/doi/10.1021/j100137a028https://doi.org/10.1021/j100137a028research-articleACS PublicationsRequest reuse permissionsArticle

We have successfully improved the J/sub c/ value of Bi-2212 round wire to 500 kA/cm/sup 2/ at 4.2 K in self-field. The J/sub c/ value strongly depended on the filament size, aspect ratio, and geometry. Adjusting the filament size made it possible to obtain wires with J/sub c/ values higher than 450 kA/cm/sup 2/ in a range of wire diameters from 0.8 to 1.3 mm. The J/sub c/ value remained constant up to an applied tensile strength of 150 MPa. A 1 + 6 stranded cable fabricated using 1.02 mm diamete

Abstract Multiple-angle incidence resolution spectrometry (MAIRS), originally developed in our group, is a unique spectroscopic technique for analyzing the structure of molecular aggregates in a thin film, which requires only the refractive index of the film for attaining an analytical accuracy of three significant digits. Since MAIRS is robust to the surface roughness of the film, rough films prepared by using the spin-coating, bar-coating, or drop-casting techniques can be analyzed with a good

A novel analytical technique based on the detection of minute bands in a mixture spectrum with the use of principal-component analysis (PCA) is presented. This new aspect of PCA indicates that overlapped spectra of some components can be separated with no a priori knowledge of the components when the absorbances of the components vary greatly. This technique can be used for the detection of minute chemical species. The concept was confirmed by computer simulations. In the simulations, abstract s

The hydration structure of the 'strongly bound water' around the sulfonic acid (SA) groups in Nafion, which has recently been revealed by (1)H NMR spectroscopy (Anal. Chem., 2013, 85, 7581), is studied using infrared spectroscopy with the aid of quantum chemical (QC) calculations. During a heated drying process, bulky water is firstly dehydrated, which is followed by the disappearance of the hydronium ion and the appearance of bands that have been assigned to the fully dehydrated species at 140

A noise reduction method was developed for solid-state nuclear magnetic resonance spectroscopy using multivariate analysis. Principal component analysis was first applied for cross-polarization/magic angle spinning and ¹³C spin-lattice relaxation measurements of solid-state nuclear magnetic resonance array spectra. The contact time of cross-polarization/magic angle spinning and the delay time in spin-lattice relaxation measurements were continuously changed to obtain a series of spect

A novel measurement technique of pure out-of-plane vibrational modes of thin films on a nonmetallic substrate has recently been proposed, which is named multiple-angle incidence resolution spectrometry (MAIRS). Since this technique could not be replaced by other conventional techniques, MAIRS was expected to be a promising tool for analysis of thin soft materials and surface adsorbates. Nevertheless, some experimental conditions have been found to be inappropriate for MAIRS, which yields incorre