Kumiko Kamata

Photocatalytic hydrogen evolution on dye-sensitized mesoporous carbon nitride photocatalyst with magnesium phthalocyanine

Spectral sensitization of a mesoporous graphite carbon nitride (mpg-C(3)N(4)) photocatalyst was investigated by depositing magnesium phthalocyanine (MgPc) to expand the absorption to wavelengths longer than those of the principal mpg-C(3)N(4). The obtained sample, MgPc/Pt/mpg-C(3)N(4) (Pt as a cocatalyst) showed stable photocatalytic evolution of hydrogen from aqueous solution in the presence of sacrificial reagents (triethanolamine), even under irradiation at wavelengths longer than 600 nm. Increasing the amount of MgPc led to ordered MgPc aggregation on the photocatalyst surfaces. The rate of photocatalytic hydrogen evolution was highest on a sample with an amount of MgPc corresponding to a monolayer on the Pt/mpg-C(3)N(4) photocatalyst surface. The obtained action spectra of hydrogen evolution and the observation that the amount of evolved hydrogen substantially surpassed the amount of MgPc, confirm that the introduced MgPc functioned as a photocatalytic sensitizer.

Energy Spectrum of Primary Cosmic Rays Between 10**14.5-ev and 10**18-ev

Size spectra of electrons (Ne) and muons (Nmu ) are obtained from the Akeno extensive air-shower experiment. The primary spectrum estimated from each spectrum is the same and is expressed by J(E0)dE0(4.0-5.0)*10-23(E0/1015.67)- gamma dE0 m-2 s-1 sr-1 where gamma =2.62+or-0.12 below and gamma =3.02+or-0.05 above 1015.67 eV. There is no other significant change of slope in either the electron or the muon size spectrum beyond the corresponding energy 1015.67 eV.

Anisotropy of the arrival direction of extensive air showers observed at Akeno

The anisotropy of the arrival direction of the primary cosmic ray of energy 1015 to 1018 eV is studied using approximately 300000 showers observed in 1981 and 1982 at the EAS array at Akeno. The anisotropy of the second harmonics appears to be (1.1+or-0.4)% in the region 1016 to 1017 eV. The showers with rich muon content seem to come preferentially from a direction of about 230 degrees in the right ascension. No statistically meaningful anisotropy is found for muon-poor showers.

Size dependence of frequency attenuation length of extensive air showers observed at Akeno

The size dependence of the frequency attenuation length ( Lambda ) of extensive air showers has been studied at Akeno for electron sizes between 105 and 108.5. Lambda decreases with increasing size up to 106 and increases slowly above 107. The value between 107 and 108 is 99+or-7 g cm-2. This indicates that the depth of the shower maximum above a few 1016 eV is shallower than that obtained by optical methods and is consistent with that from the equiintensity cut method. The result supports the view that heavy enriched primary particles with a conservative interaction model or proton-dominated primaries with interactions of high multiplicity are required.