Aoyama Gakuin University

About: Aoyama Gakuin University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Superconductivity & Thin film. The organization has 3494 authors who have published 6419 publications receiving 115648 citations. The organization is also known as: Aoyama gakuin daigaku.

Catalysis of mononuclear aquaruthenium complexes in oxygen evolution from water: a new radical coupling path using hydroxocerium(IV) species.

Abstract: The mechanism of O2 evolution from water catalyzed by a series of mononuclear aquaruthenium complexes, [Ru(terpy)(bpy)(OH2)]2+, [Ru(tmtacn)(R2bpy)(OH2)]2+ (R=H, Me, and OMe; R2bpy=4,4′-disubstituted-2,2′-bipyridines), and [Ru(tpzm)(R2bpy)(OH2)]2+ (R=H, Me, and OMe), is investigated, where terpy=2,2′:6′,2′′-terpyridine, bpy=2,2′-bipyridine, tmtacn=1,4,7-trimethyl-1,4,7-triazacyclononane, and tpzm=tris(1-pyrazolyl)methane. The kinetics of O2 evolution is investigated as a function of either the catalyst concentration or the oxidant concentration by employing Ce(NH4)2(NO3)6 as an oxidant; these catalysts can be classified into two groups that have different rate laws for O2 evolution. In one class, the rate of O2 evolution is linear to both the catalyst and Ce4+ concentrations, as briefly reported for [Ru(terpy)(bpy)(OH2)]2+ (S. Masaoka, K. Sakai, Chem. Lett. 2009, 38, 182). For the other class, [Ru(tmtacn)(R2bpy)(OH2)]2+, the rate of O2 evolution is quadratic to the catalyst concentration and independent of the Ce4+ concentration. Moreover, the singlet biradical character of the hydroxocerium(IV) ion was realized by experimental and DFT investigations. These results indicate that the radical coupling between the oxygen atoms of a RuVO species and a hydroxocerium(IV) ion is the key step for the catalysis of [Ru(terpy)(bpy)(OH2)]2+ and [Ru(tpzm)(R2bpy)(OH2)]2+, while the well-known oxo-oxo radical coupling among two RuVO species proceeds in the catalysis of [Ru(tmtacn)(R2bpy)(OH2)]2+. This is the first report demonstrating that the radical character provided by the hydroxocerium(IV) ion plays a crucial role in the catalysis of such ruthenium complexes in the evolution of O2 from water.

Interlayer magnetoresistance due to chiral soliton lattice formation in hexagonal chiral magnet CrNb3S6.

Abstract: We investigate the interlayer magnetoresistance (MR) along the chiral crystallographic axis in the hexagonal chiral magnet CrNb3S6. In a region below the incommensurate-commensurate phase transition between the chiral soliton lattice and the forced ferromagnetic state, a negative MR is obtained in a wide range of temperature, while a small positive MR is found very close to the Curie temperature. Normalized data of the negative MR almost falls into a single curve and is well fitted by a theoretical equation of the soliton density, meaning that the origin of the MR is ascribed to the magnetic scattering of conduction electrons by a nonlinear, periodic, and countable array of magnetic soliton kinks.

The 2009 multiwavelength campaign on Mrk 421: variability and correlation studies

Abstract: Aims. We perform an extensive characterization of the broadband emission of Mrk 421, as well as its temporal evolution, during the non-flaring (low) state. The high brightness and nearby location (z = 0.031) of Mrk 421 make it an excellent laboratory to study blazar emission. The goal is to learn about the physical processes responsible for the typical emission of Mrk 421, which might also be extended to other blazars that are located farther away and hence are more difficult to study. Methods. We performed a 4.5-month multi-instrument campaign on Mrk 421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. This extensive radio to very-high-energy (VHE; E> 100 GeV) γ-ray dataset provides excellent temporal and energy coverage, which allows detailed studies of the evolution of the broadband spectral energy distribution. Results. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. Conclusions. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk 421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.

English in Japanese society: Language within language

Abstract: This paper highlights one of the most conspicuous socio‐linguistic issues involving English in Japanese society: English loan words in Japanese Lexical, grammatical, and pragmatic borrowing from English into Japanese is a complex phenomenon and is explored here in three mutually related terms: structural, functional, and socio‐linguistic First, a formal analysis is presented to show structural and semantic changes which English loans go through in their Japanisation processes Second, the roles that they are expected to play (especially as euphemisms) are depicted Third, the social factors that drive the influx are examined from the perspective of the nation's kanji restriction policy and compulsory English teaching programme