Nagao Y.,Japan Advanced Institute of Science and Technology
Journal of Physical Chemistry C
Solid state ionics is a research field attracting much current attentions because of the ideal power sources for use with portable electronic devices having high power-to-weight ratios. One of the most urgent subjects in this field is to understand proton transport properties at the interface between inorganic materials and polymer electrolyte from the viewpoint of developing much more powerful energy. In this study, a 150-nm-thick Nafion thin film was prepared by spin-coating on a silicon (Si) substrate to investigate the proton transport property at the interface. The infrared (IR) p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) technique was applied to investigate the in-plane (IP) and out-of-plane (OP) spectra to the surface. The IP spectrum showed a well-known spectrum, but the OP spectrum was quite different from the IP spectrum. An anomalous IR peak was observed in the OP spectrum at 1260 cm-1. From density functional theory (DFT) calculations, this peak was attributed to the -SO3H vibration modes between two sulfonic acid groups with hydrogen bonds. These results demonstrate that the Nafion thin film on Si substrate had a highly oriented structure with the sulfonic acid groups at the side chain. Impedance measurements of Nafion thin film were conducted to investigate the proton transport property of the Nafion thin film on SiO2 substrate. The proton conductivity of the thin film exhibited a lower value than that of the commercial Nafion membrane. The low proton conductivity of the Nafion thin film was related with these highly oriented structures. © 2013 American Chemical Society. Source
Ozaki T.,Japan Advanced Institute of Science and Technology
Physical Review B - Condensed Matter and Materials Physics
An efficient low-order scaling method is presented for large-scale electronic structure calculations based on the density-functional theory using localized basis functions, which directly computes selected elements of the density matrix by a contour integration of the Green's function evaluated with a nested dissection approach for resultant sparse matrices. The computational effort of the method scales as O [N ( log2 N ) 2], O (N2), and O (N7/3) for one-, two-, and three-dimensional systems, respectively, where N is the number of basis functions. Unlike O (N) methods developed so far the approach is a numerically exact alternative to conventional O (N3) diagonalization schemes in spite of the low-order scaling, and can be applicable to not only insulating but also metallic systems in a single framework. It is also demonstrated that the well separated data structure is suitable for the massively parallel computation, which enables us to extend the applicability of density-functional calculations for large-scale systems together with the low-order scaling. © 2010 The American Physical Society. Source
Japan Advanced Institute of Science and Technology | Date: 2012-05-07
The object is to provide a universal joint that, has a secure range of motion, does not deviate from the center of rotation, and does not generate bending moments between itself and a joint that links a plurality of movable members. A plurality of movable members (
Japan Advanced Institute of Science and Technology | Date: 2012-11-13
To provide a polymer material having properties that allow the polymer material to replace a polyimide and a polyamide synthesized from a petroleum raw material, said polymer material being synthesized from a raw material derived from natural molecules. [Solution] This polymer material is obtained by polymerizing a polymer raw material comprising a dimer of 4-amino cinnamic acid or a dimer of a 4-amino cinnamic acid derivative, which are natural molecules, wherein the carboxyl group is protected by an alkyl chain. The TGA curve of a polyamide acid (PAA-1) and a polyimide (PI-1) according to the present invention is shown in FIG.
Japan Advanced Institute of Science and Technology | Date: 2014-03-27
The present invention provides a new photoreactive compound which can be used in technologies for photoreactions of nucleic acid, and also provides a photoreactive crosslinking agent comprising the above photoreactive compound. A photoreactive compound represented by the following formula I can be used.