著者

平山 英夫 近藤 健次郎 海野 泰裕 松村 宏 岩瀬 広 柚木 彰 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J14.048, (Released:2015-06-30)

参考文献数

16

被引用文献数

1

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A rapid and simple method to measure the concentration of 90Sr in water by measuring β-rays from 90Y was presented. Under the situation that 90Sr/90Y, 134Cs and 137Cs are the main radionuclides included in the water sample, only β-rays from 90Y can transmit through 1.5-mm-thick polyethylene. From this fact, it is possible to measure β-rays from 90Y using a β-ray detector, such as the GM-counter, set beneath the 1.5-mm-thick bottom of the water bottle containing the sample with 90Sr/90Y. The acrylic resin collimator having 0 cm, 1.00 cm, 1.50 cm or 3.00 cm diameter was made to detect β-rays at the fixed region of the GM-counter used. Contributions from bremsstrahlung produced by β-rays and γ-rays from radionuclides such as 134Cs and 137Cs/137mBa are removed by subtracting the count rate measured with a 1.00 cm acrylic resin collimator without a hole as the background count rate. The developed method was studied using the bottle routinely used at the Fukushima Daiichi Nuclear Power Station. It was confirmed that the developed method can be applied to measure the 90Sr concentration in water to the order of several Bq/cm3 if 134Cs and 137Cs concentrations are less than or equal to the 90Sr/90Y concentration.

著者

近藤 健次郎 平山 英夫 平 雅文 松村 宏 岩瀬 広 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

pp.J14.034, (Released:2015-06-30)

参考文献数

16

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Strontium-90/Y-90 are major radionuclides observed in the water samples tested recently at the site of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. A simple method of evaluating Sr-90 concentration in these water samples by measuring β rays from Y-90 with a GM-detector setup was developed. By applying the precipitation method, Sr-90 and Y-90 were separated and quantitatively collected with a filter. β rays from Y-90 in the filter were measured two times at appropriate intervals by inserting a polyethylene plate of 2 mm thickness as a β-ray absorber. The contribution of γ rays from Cs-134 and Cs-137 to the Y-90 count rates was quantitatively evaluated using a 10-mm-thick acrylic resin plate. From the parent-daughter relationship between Sr-90 and Y-90, the Sr-90 concentration was evaluated using the conversion coefficient of Y-90 count rate (cps) to Sr-90 concentration (Bq/cm3). It was verified that Sr-90 concentration of below 0.01 Bq/cm3 in water samples can be correctly measured by this simple method.

著者

佐波 俊哉 佐々木 慎一 飯島 和彦 岸本 祐二 齋藤 究

出版者

Atomic Energy Society of Japan

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.10, no.3, pp.163-169, 2011 (Released:2011-07-29)

参考文献数

6

被引用文献数

11 12

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The time variations in the dose rate and γ spectrum of radio nuclides originating from the accident of Fukushima Daiichi Nuclear Power Station were measured at Tsukuba City, Ibaraki, during the period from 15th March to 9th April 2011. The radiation dose peaked three times during the period from 15th to 16th March (1.27 μSv/h at maximum). The contribution of Xe-133 to the dose rate was observed from the γ spectrum obtained from the 5 h measurement during the peaks on 15th and 16th March, indicating that radioactive plume passed through Tsukuba City at that time. After the peaks, a dose rate increase with rainfall was observed on 21th March, dominating the integral dose rate measured at Tsukuba City. The dose after the rainfall comes from I-131, Cs-134, and Cs-137 that can be observed as peaks in the spectra.

著者

平井 達哉 本川 祐治 佐々木 慎一 丹京 真一

雑誌

デジタルプラクティス (ISSN:21884390)

巻号頁・発行日

vol.9, no.3, pp.627-642, 2018-07-15

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近年,ソフトウェアの脆弱性が明らかになってから,その点を突くサイバー攻撃が行われるまでの時間が短くなり,実被害を生じる例が増大している.生じる被害を抑えるために,各事業者では,セキュリティインシデントを未然に防止すること,セキュリティインシデントを生じた場合には迅速に対応することが,急務になってきている.それらを達成できるようにするには,各企業内に設置されているCSIRTが,各地で発生しているサイバー攻撃の動向やソフトウェアの脆弱性の情報,それらへの対策の方法を早期に入手できること,情報システム・機器の管理者や利用者に迅速に対策情報を通知できること,通知を受けた管理者や利用者が各機器に対して迅速に対策を実行できること等が必要である.そのためには,CSIRTがソフトウェア開発企業や国内外の情報収集機関等が発信するソフトウェアの脆弱性やサイバー攻撃,およびそれらへの対策に関する情報を入手し,情報を整理した上で,必要なものを,自事業者内や下位の組織・事業者等に展開できる必要がある.このような背景から,関連する組織,事業者,および人員の間で,情報を共有することを適切に支援するICTシステムが存在することが望まれる.上記観点から,我々はまず,被害を抑制するためにCSIRTが遂行する必要がある作業を分析し,その上でそれらをより迅速にCSIRTが遂行できるようにするためのICTシステムを開発・構築した.現在その有用性について検証を進めている.

著者

高橋 由雅 佐々木 慎一

出版者

The Society of Synthetic Organic Chemistry, Japan

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.45, no.11, pp.1087-1097, 1987-11-01 (Released:2010-01-22)

参考文献数

15

被引用文献数

3

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It is well known that chemical structure diagram or three-dimensional structure of a compound molecule involves much information related to biological activity, reactivity, or various physicochemical properties on itself. It is a very important thing in a wide range of chemical research to compare the chemical compounds on the basis of such structural information. Especially, in the area of structure-activity studies, to investigate structural feature such as functional groups or substructural fragments, common to a group of chemical compounds exhibiting a particular biological activity often provides us with very useful and objective information which may be resulted in hypothetical pharmacophore.In this article, a couple of approaches for the automated recognition of common structural patterns among drug molecules will be described. One is related to the maximal common substructure search which can be used to find some topological pharmacophore, and the other one is for the common geometrical pattern search in which three-dimensional geometry of molecules are taken account. The latter approach may be used to identify a certain topographical or three-dimensional pharmacophore. The basic algorithms and related software systems will be summarized with some illustrative examples.

著者

平山 英夫 近藤 健次郎 海野 泰裕 松村 宏 岩瀬 広 柚木 彰 佐々木 慎一

出版者

一般社団法人 日本原子力学会

雑誌

日本原子力学会和文論文誌 (ISSN:13472879)

巻号頁・発行日

vol.14, no.3, pp.141-150, 2015 (Released:2015-08-15)

参考文献数

16

被引用文献数

1

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A rapid and simple method to measure the concentration of 90Sr in water by measuring β-rays from 90Y was presented. Under the situation that 90Sr/90Y, 134Cs and 137Cs are the main radionuclides included in the water sample, only β-rays from 90Y can transmit through 1.5-mm-thick polyethylene. From this fact, it is possible to measure β-rays from 90Y using a β-ray detector, such as the GM-counter, set beneath the 1.5-mm-thick bottom of the water bottle containing the sample with 90Sr/90Y. The acrylic resin collimator having 0 cm, 1.00 cm, 1.50 cm or 3.00 cm diameter was made to detect β-rays at the fixed region of the GM-counter used. Contributions from bremsstrahlung produced by β-rays and γ-rays from radionuclides such as 134Cs and 137Cs/137mBa are removed by subtracting the count rate measured with a 1.00 cm acrylic resin collimator without a hole as the background count rate. The developed method was studied using the bottle routinely used at the Fukushima Daiichi Nuclear Power Station. It was confirmed that the developed method can be applied to measure the 90Sr concentration in water to the order of several Bq/cm3 if 134Cs and 137Cs concentrations are less than or equal to the 90Sr/90Y concentration.