Proceedings of the Japan Academy, Series B

C₂ and λ8727[CI] Lines in Some Carbon Stars

Yoshio FUJITA

1994 Volume 70 Issue 2 Pages 15-18
Published: 1994
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.70.15

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Behaviours of C₂b¹Π_u-x¹ ∑⁺_g System and λ8727[CI] lines in the photographic infrared spectral region of some carbon stars were discussed in connection with their spectral sub-classes.

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Stress Fields in Slabs Penetrating into the Lower Mantle, and Rheology and Composition of the Lower Mantle

Tomoeki NAKAKUKI, Hiromi FUJIMOTO

1994 Volume 70 Issue 2 Pages 19-24
Published: 1994
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.70.19

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Focal mechanisms of deep-focus earthquakes show compressional stress fields in the deepest part of upper mantle slabs. We examine mechanisms to realize the stress fields using numerical models of slabs interacting with a phase and/or a chemical boundary. The compressional stress field implies that compositional density difference greater than 2% exists at the 660km discontinuity, or that viscosity increases by a factor larger than a few tens and linear-law rheology dominates the flow mechanism in the lower mantle.

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A Trial to Detect the Aberration of Ru Isotopic Ratios Due to Radioactive Decay of Technetium

Akimasa MASUDA, Min HUANG

1994 Volume 70 Issue 2 Pages 25-29
Published: 1994
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.70.25

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As our basic work to establish precisely the reference isotopic abundance ratios of ruthenium, we examined carefully the isotopic abundance ratios of seven stable isotopes of ruthenium using its solution prepared by Aldrich Chemical Co., Inc., Milwaukee, WI, USA. Prior to our examination, Poths, Schmitt-Strecker and Begemann (1987) at Max-Planck-Institut für Chemie, Mainz, also determined precisely the corresponding ratios using Ru of Ventron-Alpha Co. Our ⁹⁸Ru/⁹⁹Ru ratio is about 11 ε higher than that reported by Poths et al., while our ¹⁰⁴Ru/⁹⁹Ru ratio is about 10 ε lower than that by them. As regards ⁹⁶Ru, ¹⁰⁰Ru, ¹⁰¹Ru and potentially ⁹⁹Ru, there are little if any remarkable differences between us and them. The difference in ¹⁰⁴Ru/⁹⁹Ru is judged to reflect the interference from (⁸⁸Sr¹⁶O)+ ion in their measurement. However, it is difficult to account for the difference in ⁹⁸Ru/⁹⁹Ru ratio. One cannot rule out the possibility that this has resulted from the difference in nuclear-decay contribution from ⁹⁸Tc.

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