巻号一覧
27 巻 (1993)
- 6 号 p. 367-
- 4-5 号 p. 181-
- 3 号 p. 131-
- 2 号 p. 59-
- 1 号 p. 1-
27 巻, 6 号
選択された号の論文の6件中1～6を表示しています
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Yuzuru Nakaguchi, Keizo Hiraki1993 年 27 巻 6 号 p. 367-374
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーSelenium in natural waters was chemically specified at 16 stations from Lake Biwa to Osaka Bay. The concentrations of selenium (IV), selenium (VI) and organic selenium in Lake Biwa ranged from 0.04 to 0.36, from 0.00 to 0.36, and from 0.00 to 1.97 nM, respectively. The concentration of organic selenium was highest at the depth of the maximal of chlorophyll a concentration in the Lake Biwa water. The concentrations of selenium (IV), selenium (VI) and organic selenium in the Yodo River ranged from 0.12 to 0.37, from 0.02 to 0.32, and from 0.32 to 0.18 nM, respectively. In coastal Osaka Bay, the concentrations of selenium (IV), selenium (VI) and organic selenium ranged from 0.05 to 0.31, from 0.09 to 0.50, and from 0.14 to 0.77 nM, respectively.抄録全体を表示PDF形式でダウンロード (1856K) -
Takushi Yokoyama, Yumi Sato, Yonezo Maeda, Toshikazu Tarutani, Ryuichi ...1993 年 27 巻 6 号 p. 375-384
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーIn the deposition of siliceous material from geothermal water, a relationship between chemical compositions of geothermal waters and siliceous deposits was investigated. The results indicated that iron and aluminium were concentrated into these siliceous deposits. For the chemical state of the iron in the deposits, some oxides and oxyhydroxides, sulfide and amorphous iron silicate were identified by powder X-ray diffraction and 57Fe Mössbauer spectroscopy. For the aluminium, two states were detected by 27Al MAS NMR: 6-coordinate aluminium (such as aluminium hydroxide) and 4-coordinate aluminium substituting a Si atom site in the deposit. In some deposit samples, both 4 and 6-coordinate aluminium were detected, but in others only the former was found.抄録全体を表示PDF形式でダウンロード (2479K) -
Minoru Uzaki, Keita Yamada, Ryoshi Ishiwatari1993 年 27 巻 6 号 p. 385-389
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーCarbon isotope compositions of long-chain n-alkanes (C27∼C33) in selected samples from a Tokyo Bay sediment core (0∼3 m in depth) were determined by gas chromatography/isotope ratio mass spectrometry (GC-IRMS). δ13C values of the n-alkanes in the shallow sections (0∼40 cm in depth, present∼1965 AD) range from –31.5 to –28.2‰ relative to the PDB standard, showing that even carbon-numbered n-alkanes are isotopically heavier than the odd numbered ones. The n-alkanes in the deeper sections (190∼220 cm in depth) show the values ranging from –29.6 to –31.4‰ (average value: –30.7 ± 0.6‰) without any significant difference among the n-alkanes. The results of n-alkanes in the shallow sections are explained by an addition of oil-derived n-alkanes to higher plant wax n-alkanes observed in the deeper sections.抄録全体を表示PDF形式でダウンロード (1559K) -
Hiroyuki Kitagawa, Hideki Wada1993 年 27 巻 6 号 p. 391-396
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーδ13C fluctuations within a ring and secular δ13C changes of a Japanese cedar tree from Mt. Amagi in the Izu Peninsula, central Japan, are presented. δ13C values within a ring show a characteristic fluctuation in which the δ13C values in the early wood layer are smaller than that in the late wood layer. The mean peak to peak amplitude of the seasonal δ13C fluctuation is 1.4 ± 0.3‰, which has not apparently changed with time during the past 120 years. The δ13C secular change in annual growth rings shows a downward trend with time, with a δ13C rise of about 1‰ between 1940 and 1960. The δ13C falls in annual growth rings of Japanese cedar were 0.55‰ from 1860 to 1940 and 1.05‰ from 1960 to 1980, respectively.抄録全体を表示PDF形式でダウンロード (1741K) -
Hiroyuki Kitagawa, Eiji Matsumoto1993 年 27 巻 6 号 p. 397-402
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーδ13C records of annual growth rings of two Japanese cedars (Cryptomeria japonica) from Yakushima Island, southern Japan are presented for the past 200 years. Some portions of the short-term fluctuations in the δ13C records from the Japanese cedars are correlated with the variabilities of the ring-thickness index. Regressions between the ring-thickness indices and δ13C values were used to “correct” the δ13C records for local climate and environmental effects. These corrected δ13C records from the two Japanese cedars show a steady downward trend with time, but with pronounced short-term fluctuations superimposed on the trend. The overall δ13C fall from 1870 to the present is between 1.2–1.4‰, consistent with the δ13C records of atmospheric CO2 estimated from ice-core bubbles, which show a fall of 1.14 ± 0.15‰ from 1740 to the present (Friedli et al., 1986). The δ13C fall seems to be related to the increase in the concentration of atmospheric CO2 as a result of fossil fuel burning and deforestation. The corrected δ13C records show small increases at 1900 and 1950, which can not be explained satisfactorily at present.抄録全体を表示PDF形式でダウンロード (1643K) -
Takahiro Tagami, Ken Shibata1993 年 27 巻 6 号 p. 403-406
発行日: 1993/12/20
公開日: 2008/04/08
ジャーナル フリーFour apatite fission track (AFT) and two zircon fission track ages were determined on the Ryoke granitic rocks, located close to the Median Tectonic Line (MTL), Southwest Japan. The AFT ages range from ∼9.3 to ∼32 Ma, and thus can be correlated to the “young” AFT ages previously found near the MTL; meanwhile, zircon ages are around 65 Ma. Because some of the localities lie in the western portion of the Ryoke Belt that was not studied previously, it is suggested that the region characterized by the “young” AFT ages, probably representing later thermal events along the MTL, may be extensive to the overall Ryoke Belt.抄録全体を表示PDF形式でダウンロード (1281K)
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