著者

丸山 誠史 服部 健太郎 平田 岳史

出版者

日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.48, no.3, pp.187-199, 2014-09-25 (Released:2014-10-10)

参考文献数

41

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Concentrations of uranium and thorium in commercial bottled mineral waters (81 domestic and 11 foreign products) have been analyzed using ICP-MS. Domestic bottled mineral waters exhibit very wide range of the uranium concentrations (0.1–3300 ng/L). However uranium concentrations of most samples were below 100 ng/L. There is no obvious correlation between the values of hardness and the uranium concentrations of the domestic bottled mineral waters. The uranium concentrations of foreign bottled mineral waters tended to be much higher than those of domestic ones (up to 4000 ng/L), and the values of hardness correlate roughly with the uranium concentration. It may be due to interactions between limestone and groundwater. Thorium concentrations of both domestic and foreign bottled mineral waters are typically less than 3.0 ng/L. Concentrations of uranium and thorium in bottled mineral waters were greatly lower than provisional guideline values defined by WHO. Therefore, it can be considered that there is no health risk chemically/radioactively induced by natural uranium and thorium in commercial mineral waters currently available in Japan, especially in Kyoto City.

著者

坂崎 貴俊 加納 靖之 大邑 潤三 服部 健太郎

出版者

京都大学生存圏研究所

雑誌

生存圏研究 (ISSN:1880649X)

巻号頁・発行日

vol.11, pp.64-70, 2015-11-10

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1856年09.月23日(旧暦安政3年08月25日)に江戸を直撃した台風について調べた。主として安政風聞集に基づき被害状況を報告すると共に、各地の日記記録などを併せて台風の進路を含む当時の気象場を推定した。その結果、台風は太平洋上を猛スピードで北上し相模に上陸、江戸の西側を通過して北へ抜けたと推定される。猛烈な風による吹き寄せ効果により急激な高潮が生じたことが、人的・物的被害を拡大させた最大の要因と考えられる。

著者

大林 秀行 坂田 周平 山本 伸次 磯崎 行雄 服部 健太郎 平田 岳史

雑誌

日本地球惑星科学連合2016年大会

巻号頁・発行日

2016-03-10

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Most of the global events, such as formation of magma ocean, core-mantle segregation, crust formation, and/or chemical evolution of atmosphere, could be completed within the first 0.5 Byr of the Earth History, so called Hadean Eon. Despite the great importance of the Hadean Eon, no petrographic record can be found for this stage, and only geochemical information can be derived from small minerals such as zircons or other accessory minerals within zircons (e.g., apatite, muscovite, or biotite). For geochemical studies for Hadean Eon, many pioneering studies have been made based on the isotope geochemistry on zircons collected from Jack Hills and Mt. Narryer, Western Australia. It is widely recognized that zircons collected from these area have been thought one of the most principal clues for Hadean studies. Moreover, further detailed studies have been carried out from small inclusions in zircon crystals. Zircons from Jack Hills contain various mineral inclusions such as muscovite, quartz, biotite, apatite and so on, and about two-thirds of them are muscovite and quartz, probably due to secondary replacement of primary apatite (Hopkins et al., 2008, Rasmussen et al., 2011). Recently, biogenic carbon, as graphite inclusion, was recovered from 4.1 Ga zircon, but an abundance of carbon-bearing Jack Hills zircons of only about 1-in-10,000 (Bell et al., 2015). In addition, the percentage of Hadean zircons to detrital zircons in Jack Hills was as small as 7% (Holden et al., 2009). For these reasons, large number of age data for zircon grains must be defined to derive reliable and objective information concerning the Hadean history of the Earth. To overcome this, we have developed new analytical technique to define precise age data from combination of U-Pb (Pb-Pb) dating method with high sample throughput.We have developed rapid and precise dating technique for zircons using laser ablation ICP-mass spectrometer (LA-ICP-MS), equipped with two Daly ion collectors (Nu Plasma IID, Wrexham, UK). Laser ablation instrument used in this study was ESI NWR193 laser ablation system (New Wave Research, Oregon, USA). Combination of multiple collector-ICPMS system and ArF Excimer laser ablation system enables us to measure Pb-Pb age for the sample within 10 second/spot, and uncertainties in the resulting Pb-Pb age data can be minimized by the multiple-collector system setup. Based on the age determination system using LA-MC-ICPMS technique, we just started to measure Pb-Pb age data from 180 grains of zircons within an hour . In this presentation, difference in the resulting age histogram for the zircons collected from Jack Hills will be discussed, and detailed observation for various inclusions in the Hadean zircons will be demonstrated in this talk.

著者

五十嵐 昭男 吉田 孝文 服部 健太郎

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.60, no.578, pp.p3372-3379, 1994-10

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Rolling motion is one cause of mechanical sound. Rolling sound may cause serious problems when it is excessive in machines and structures, for example. A series of studies have been carried out in order to obtain basic information for the reduction of rolling sound. This third report concerns the generation mechanism of the sound. Horizontal square steel plates with different surface finishes were simply supported at four points. Nylon and steel balls with different surface finishes were rolled at various rolling velocities on the plates, and the sound was measured using a condenser microphone. Surface topographies of the balls and plates were also measured by a device measuring the deviation from circular form and surface roughness, respectively. The signals obtained in the measurements were analyzed by an FFT analyzer. From the experiments, analysis and considerations, the generation mechanism of the sound was clarified.