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Author Maekawa, Kiyoaki|
Published Date 1994
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue5-6
Content Type Journal Article
Author Suzuka, Ichio|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue5-6
Content Type Journal Article
Author Tanizaki, Yoshiro| Kitani, Hikaru| Okazaki, Morihiro| Mifune, Takashi| Mitsunobu, Fumihiro| Sugimoto, Keisuke|
Published Date 1993
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue3-4
Content Type Journal Article
Author Takeo, Masahiko|
Published Date 1993-02-27
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue1-2
Content Type Journal Article
Author Suekane, Takashi| Oshima, Mitsuko| Motomizu, Shoji|
Published Date 2004-12-22
Publication Title 分析化学
Volume volume54
Issue issue10
Content Type Journal Article
JaLCDOI 10.18926/ESR/13945
Title Alternative solubility and polymerization of silica in salt solutions
FullText URL ESR_2_63.pdf
Author Sugita, Hajime| Yamamoto, Masahiro|
Abstract The solubility of amorphous silica was determined in sodium chloride,potassium chloride, magnesium chloride and calium chloride solutions from 0.01 to 1moI/I and at temperatures of 21,36,50 and 65℃. The Setchenow equation was applied to the results, which enabled us to estimate the equilibrium concentration of "dissoloved silica" (molybdate-reactive silica) in the studied chloride solutions. Next, the effects of pH, supersaturation of silica and salt concentration on the polymerization rate of silica were investigated at 35℃. In the pH range from 6.4 to 7.9, the maximum polymerization rate increased with increasing pH. The maxima occurred when dissoloved silica decreased by 25% of the initial supersaturation concentrations irrespective of pH. The polymerization rate was found to be dependent on the supersaturation degree rather than on the supersaturation concentration of silica. The results in magnesium chloride solutions suggest that magnesium ions may act as nuclei in the formation of colloidal silica in geothermal waters.
Keywords amorphous silica solubility polymerization
Publication Title Okayama University Earth Science Report
Published Date 1995-09-20
Volume volume2
Issue issue1
Start Page 63
End Page 70
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310447
JaLCDOI 10.18926/ESR/13943
Title Alternative Water-soluble materials on volcanic ash from the 1990-94 eruption of the Unzenn volcano
FullText URL ESR_2_55.pdf
Author Akagi, Seishi| Yamamoto, Masahiro|
Abstract Water-soluble materials on volcanic ash from the Unzen volcano collected from February, 1991 to July, 1994 were chemically analyzed. They were similar in chemical characteristics to those obtained from other volcanoes. Chemical compositions varied even for materials from the same pyroclastic flow. C1 contens increased with increasing residence time of volcanic ash in air, but SO4 contents were almost fixed. It therefore seems that the reaction of volcanic ash with HC1 proceeds even at low temperatures, whereas the reaction with SO2 takes place only at high temperatutes.
Keywords volcanic ash volcanic gas Unzen volcano C1/SO4 ratio water-soluble material
Publication Title Okayama University Earth Science Report
Published Date 1995-09-20
Volume volume2
Issue issue1
Start Page 55
End Page 62
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310484
JaLCDOI 10.18926/ESR/13908
FullText URL ESR_6_39.pdf
Author Yamamoto Masahiro| Ichimoto Hideo| Komatsu Shinji| Yamashita Ruka|
Abstract Hydrogen and oxygen isotope rations of thermal waters from 46 spas in Okayama Prefecture range from -62.6 to -29.2% in δD and from -10.0 to -4.4% in δ18O, respectively. The isotope rations indicate that all but one of the thermal water in Okayama prefecture are meteoric in origin. The Ofuku thermal water is the only exception, which is probably a mixture of seawater and meteoric water with the ratio of about 1. Sulfur isotope rations of dissolvel sulfate in the thermal waters range from -6.2 ti 59.3% in δ34S. The high δ34S values observed in some thermal waters may be due to bacterial reduction of sulfate.
Keywords Hydrogen isotope ratio Oxygen isotope ratio Sulfur isotope ratio Thermal water Spa Okayama
Publication Title Okayama University Earth Science Report
Published Date 1999-09-20
Volume volume6
Issue issue1
Start Page 39
End Page 44
ISSN 1340-7414
language English
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310408
JaLCDOI 10.18926/ESR/13897
Title Alternative Water-soluble materials formed by the reaction between a volcanic rock and HCI and/or SO2 gases
FullText URL ESR_7_21.pdf
Author Akagi, Seishi| Yamamoto, Masahiro|
Abstract Experiments on the reaction of a volcanic rock, dacite with HCI and /or SO2 gases have been carried out at room temperature to 800℃ for understanding of the condition of the formation of water-soluble materials on volcanic ash. HCI reacted with the dacite mainly at low temperatures (≤200℃), whereas SO2 did at high temperatures (≥400℃). It was also found that CI/SO4 ratios of water-soluble materials were very high at low temperatures, but decreased rapidly with increasing temperature. In the experiments using a mixture of HCI and SO2, the cation composition at 600℃ and 800℃ was revealed to be significantly different from that at lower temperatures, suggesting the change in the reaction process with temperature.
Keywords Volcanic gas Volcanic ash Water-soluble material CI/SO4 ratio
Publication Title Okayama University Earth Science Report
Published Date 2000-09-20
Volume volume7
Issue issue1
Start Page 21
End Page 26
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310554
Author Joichi, Yasutaka| Narong, Lenghor| Takayanagi, Toshio| Oshima, Mitsuko| Motomizu, Shoji| Ura, Nobuo|
Published Date 2006-11-17
Publication Title 分析化学
Volume volume55
Issue issue9
Content Type Journal Article
Author Yamamoto, Takako| Akhmad, Sabarudin| Noguchi, Osamu| Takayanagi, Toshio| Oshima, Mitsuko| Motomizu, Shoji|
Published Date 2006-11-17
Publication Title 分析化学
Volume volume55
Issue issue9
Content Type Journal Article
JaLCDOI 10.18926/ESR/13889
FullText URL ESR_8_1_39.pdf
Author Kobyashi, Daiju| Yamamoto Masahiro|
Abstract Hydrogen and oxygen isotope ratios of thermal waters from 42 hot springs in Izu Peninsula, Shizuoka Prefecture, range from -51.7 to -24.7% in δD and from -7.9 to -4.1% in δ18O, respectively. The isotope ratios suggest that most of the thermal waters in Izu Peninsula are essentially meteoric in origin. Significantly deviated from the normal meteoric waters are thermal waters from Yumigahama, Kumomi, and Shimogamo hot springs which may be mixtures of seawater and local meteoric waters, and thermal waters from Izusan and Imaihama whose oxygen isotope ratios may have become heavier by water-rock interaction. 
Keywords Hydrogen isotope ratio Oxygen isotope ratio Thermal water Hot spring Izu Peninsula Shizuoka Prefecture
Publication Title Okayama University Earth Science Report
Published Date 2001-09-20
Volume volume8
Issue issue1
Start Page 39
End Page 44
ISSN 1340-7414
language English
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310513
JaLCDOI 10.18926/ESR/13888
Title Alternative Relationship between the water quality of three main rivers and geology of Okayama Prafecture
FullText URL ESR_8_1_29.pdf
Author Kinoshita, takuya| Matsuda, Toshihiko|
Abstract Concentrations of inorganic major components (Ca2+, Mg2+, Na+, K+, ΣFe, AI3+, HCO3, SO4, CI-, NO3, F- and SiO2) were measured in 57 water samples from three main rivers, the Yoshii, Asahi and Takahashi Rivers and their tributaries. The water quality is discussed in relation to the geological environment in the drainage basin of three rivers. The following results were obtained from the investigation. The degree of influence of rocks on the water quality was limestone≫basic rocks>clastic rocks>andesite>rhyolite>gramite. The influence of geology is clear in the riverhead but it is obscure in the downstream. The concentration of each component increases generally from the upper stream to the lower stream but that of SiO2 only decreases in the lower stream. Kaolinite is a stable mineral as a weathering prodouct from the ion compositions of three rivers. In a rough estimation, Yoshii, Asahi and Takahashi Rivers weather 303,000t, 433,000t and 1,033,000t of the rocks respectively from their basins in a year. The syrface of their basins are scraoed off 0.06mm, 0.11mm and 0.15mm respectively in a year.
Keywords Water quality River water Geology of basin Yoshii River Asahi River Takahashi River Okayama Prefecture
Publication Title Okayama University Earth Science Report
Published Date 2001-09-20
Volume volume8
Issue issue1
Start Page 29
End Page 38
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310339
Author Miyashita, Katuhiro|
Published Date 1993-08
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue7-8
Content Type Journal Article
Author Miyashita, Katuhiro|
Published Date 1993-08
Publication Title 岡山医学会雑誌
Volume volume105
Issue issue7-8
Content Type Journal Article
JaLCDOI 10.18926/ESR/13867
Title Alternative Paleoceanography of the Eastern Asia from the Last Glacial Maximum to the early Holocene
FullText URL earth_science_reports_011_1_23.pdf
Author Kan, Hironobu|
Abstract A series of marginal seas that are separated from the Pacific Ocean by island arcs developed in Eastern Asia. The environmental property of these marginal seas amplified under a sea-level lowstand during the Last Glacial Maximum (LGM). The Japan Sea was covered by low salinity water during the LGM. At the beginning of the post-glacial sea-level rise, the Oyashio Current firstly flowed into the Japan Sea throught the Tsugaru Strait. The influx of the Tsushima Current started around 10,000 yBP and become vigorously after 8,000 yBP. Meanwhile, the northward migration and influx of the Kuroshio Current into East China Sea started around 10,000 yBP and strengthened after 7,500 yBP. The route alternation of the Kuroshio Current might have contributed to the establishment of the Tsushima Current and acted as a trigger for the drastic environmental changes around the merginal seas in Eastern Asia at the time of the post-glacial sea-level rise.
Keywords Paleoceanography Last Glacial Maximum
Publication Title Okayama University Earth Science Report
Published Date 2004-12-31
Volume volume11
Issue issue1
Start Page 23
End Page 31
ISSN 1340-7414
language Japanese
Copyright Holders 岡山大学地球科学研究報告編集委員会
File Version publisher
NAID 120002310301
Author Hidaka, Hidekuni|
Published Date 1994-10
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue9-10
Content Type Journal Article
FullText URL Ana_Sci_24_505.pdf
Author Kunihiko Seno| Kazuki Matsumura| Oshima, Mitsuko| Motomizu, Shoji|
Published Date 2008-04-10
Publication Title Analytical Sciences
Volume volume24
Issue issue4
Publisher 日本分析化学会
Start Page 505
End Page 508
ISSN 0910-6340
NCID AA10500785
Content Type Journal Article
language English
OAI-PMH Set 岡山大学
Copyright Holders 日本分析化学会
File Version publisher
DOI 10.2116/analsci.24.505
Author Noguchi, Osamu| Oshima, Mitsuko| Motomizu, Shoji|
Published Date 2008-05-10
Publication Title Analytical Sciences
Volume volume24
Issue issue5
Content Type Journal Article
Author Mizobuchi, Satoshi|
Published Date 1994-10
Publication Title 岡山医学会雑誌
Volume volume106
Issue issue9-10
Content Type Journal Article