巻号一覧
25 巻 (1991)
- 6 号 p. 411-
- 5 号 p. 357-
- 4 号 p. 199-
- 3 号 p. 137-
- 2 号 p. 57-
- 1 号 p. 1-
25 巻, 6 号
選択された号の論文の5件中1～5を表示しています
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Pujing Pan, Nicholas J. Susak1991 年 25 巻 6 号 p. 411-420
発行日: 1991年
公開日: 2008/04/08
ジャーナル フリーCobalt(II) speciation in seawater and fresh waters was calculated using recent spectrophotometrically determined stability data for cobalt(II) chloride and bromide complexes in aqueous solutions, and a theoretically estimated stability constant for the cobalt(II) bicarbonate complex. Calculations for seawater suggest that 56.25% of total dissolved cobalt(II) occurs as the free ion, Co2+, 39.53% as CoCl+, 2.76% as CoCl20, 1.02% as CoSO40, and less than 1.0% as CoNH32+, CoCO30, CoHCO3+, CoCl3–, CoF+ and CoBr+. In neutral to acidic fresh waters, 90% or more of the dissolved cobalt(II) occurs as the free ion. CoCO30 becomes important in basic fresh waters (pH > 8.5), and predominant in very basic fresh waters (pH > 9.5). Co(II) organic complexes are not included in the calculations, discussions suggest that they are unlikely to be abundant in seawater. Co(II) organic complexes may, however, be important in fresh waters, and future work should investigate this possibility.抄録全体を表示PDF形式でダウンロード (2438K) -
Akira Shimoyama, Masatoshi Komiya, Kaoru Harada1991 年 25 巻 6 号 p. 421-428
発行日: 1991年
公開日: 2008/04/08
ジャーナル フリーHomologous series of low molecular weight monocarboxylic acids (C2 to C12) and γ-lactones (C5 to C12) were detected in Miocene to Pliocene sediments of Shinjo basin. Abundances of the monocarboxylic acids are 10-6 to 10-8g/g, and those of the γ-lactones are 10-7 to 10-9 g/g. The monocarboxylic acids show the unique predominance of nonanoic acid over octanoic and decanoic acids. The γ-lactones show a predominance of hexanoic lactone in most of the sediments. No δ-lactones were detected in the sediments. It seems that the two classes of organic compounds were converted from common precursors, namely cis-9 unsaturated fatty acids, during the early stages of sediment diagenesis.抄録全体を表示PDF形式でダウンロード (2160K) -
Hiroshi Satake, Seiji Takeuchi1991 年 25 巻 6 号 p. 429-435
発行日: 1991年
公開日: 2008/04/08
ジャーナル フリーThe electrolytic separation factors of tritium, (T/H)water/(T/H)hydrogen, and the relationship between the tritium enrichment factor, Tf/Ti, and the final volume of water have been evaluated for Fe-Ni and Ni-Ni electrodes. The tritium separation factor for the Fe-Ni electrodes (25.9 ± 3.4) is systematically higher than that with the Ni-Ni electrodes (14.4 ± 4.4) when the electrolysis is conducted under similar conditions. The tritium separation factor with the Fe-Ni electrodes obtained in this study is similar to that obtained in previous studies. Chemically impure mild steel used in this study as a cathode material gives a high tritium separation factor as well as pure iron employed in previous studies. The tritium enrichment factor with the Ni-Ni electrodes shows a wide variation at a given final volume, depending upon the tritium separation factor. On the contrary, the tritium enrichment factor obtained with the Fe-Ni electrodes changes as a function of the final volume. When tritium in the sample is enriched 20–25 times with the Fe-Ni electrodes, a reliable tritium enrichment factor can be obtained directly from the final volume with an accuracy of ±3.5% (2σ) without measuring the deuterium or simultaneous electrolysis of a tritiated reference water.抄録全体を表示PDF形式でダウンロード (1947K) -
Shin Toyoda, Motoji Ikeya1991 年 25 巻 6 号 p. 437-445
発行日: 1991年
公開日: 2008/04/08
ジャーナル フリーThermal stabilities of E′, Al, and Ti centers in quartz from the Mannari granite were investigated by electron spin resonance (ESR) with isothermal and isochronal annealing experiments. Second order decay kinetics best explain the results. The closure temperatures at which the ESR clocks start were estimated to be 91°C, 78°C, and 31°C for E′, Al, and Ti centers, respectively, with a cooling rate of about 10°C/Ma. Closure temperatures were also estimated for rocks around an intrusive dike. The thermal history of a quartz bearing rock can be investigated using ESR ages for different centers.抄録全体を表示PDF形式でダウンロード (2746K) -
Keisuke Nagao, Atsumi Ogata, Yayoi Miura, Jun-ichi Matsuda, Shun-iti A ...1991 年 25 巻 6 号 p. 447-451
発行日: 1991年
公開日: 2008/04/08
ジャーナル フリーA technique for noble gas mass spectrometry was applied to the K-Ar dating of very young volcanic rocks to examine the reproducibility in Ar analysis. For two selected samples TE1 (trachyandesite) and NE2 (obsidian) with relatively low atmospheric Ar and high K concentrations, five and seven analyses were performed, respectively, using small sample size (0.5 g), and they gave highly reproducible K-Ar ages. The mean ages for TE1 and NE2 were 13.0 ± 1.6(1σ) and 17.0 ± 1.4(1σ) ka, respectively. Six repeated analyses of the Quaternary reference material YZ1 of Yamagata University showed a mean age of 218 ± 11 ka, which agrees well with the reported values. These results imply the possibility that volcanic rocks as young as ten thousand years can be dated by the K-Ar method with the condition that the samples satisfy the required conditions for K-Ar dating.抄録全体を表示PDF形式でダウンロード (1454K)
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