※一部利用できない機能があります
| 1.
論文（リポジトリ） |
論文（リポジトリ）
|
Nakasone, Shunya ; Yokoyama, Sumi ; Takahashi, Tomoyuki ; Ota, Masakazu ; Kakiuchi, Hideki ; Sugihara, Shinji ; Hirao, Shigekazu ; Momoshima, Noriyuki ; Tamari, Toshiya ; Shima, Nagayoshi ; Atarashi-Andoh, Mariko ; Fukutani, Satoshi ; Ishimine, Akinobu ; Furukawa, Masahide ; Tanaka, Masahiro ; Akata, Naofumi
概要:
This paper presents an evaluation of a rapid pretreatment method for tritium analysis, that uses ion exchange resins (th
…
e batch method). The standard water samples were prepared with river water collected in Okinawa, Japan. Powdex resin was used in this study, which is an ion exchange resins in the form of powder beads. First, 100 mL of the standard sample was stirred with the cation exchange (PCH) and anion exchange (PAO) resins, as well as with activated carbon. To determine the optimal stirring time, we tested stirring times of 5, 10, 20 and 30 min. Additionally, to determine a suitable amount of ion exchange resin for environmental water samples, variations in the amount of resin and activated carbon were tested. Under the conditions of Experiment-3 (0.3 g, 0.3 g and 0.6 g of PCH, PAO and activated carbon, respectively) and with a stirring time of 5 min, electrical conductivity values of less than 1 mSm^<−1> were achieved. These results demonstrate the effectiveness of the removal of impurities in the sample water by ion exchange resins and confirm that such an effect can be achieved during a short period of time (i.e., in 5 min).
論文 続きを見る |
||||
| 2.
論文（リポジトリ） |
論文（リポジトリ）
|
2. Development of Field Estimation Technique and Improvement of Environmental Tritium Behavior Model
Yokoyama, Sumi ; Takahashi, Tomoyuki ; Ota, Masakazu ; Kakiuchi, Hideki ; Sugihara, Shinji ; Hirao, Shigekazu ; Momoshima, Noriyuki ; Tamari, Toshiya ; Shima, Nagayoshi ; Atarashi-Andoh, Mariko ; Fukutani, Satoshi ; Nakasone, Shunya ; Furukawa, Masahide ; Tanaka, Masahiro ; Akata, Naofumi
概要:
To estimate the environmental transfer of tritium into the atmosphere and to establish tritium analysis techniques, this
…
study improves our previous compartment model and proposes new analytical technique based on the microwave heating method and a water-sample purification technique using ion resin. This article introduces a new conceptual approach for estimating environmental tritium behavior.
論文 続きを見る |
||||
| 3.
論文（リポジトリ） |
論文（リポジトリ）
|
Akata, Naofumi ; Kakiuchi, Hideki ; Tanaka, Masahiro ; Shima, Nagayoshi ; Shiroma, Yoshitaka ; Tokonami, Shinji ; Hosoda, Masahiro ; Ishikawa, Yoshio ; Furukawa, Masahide ; Sanada, Tetsuya
概要:
We have developed a rapid sampling system for measuring the tritium in atmospheric water vapor. The system consists of a
…
high-efficiency particulate air filter cartridge, an oil-free compressor, a water-vapor-separating module with hollow fiber membranes, two cold traps, and an oil-free rotary pump. Compressed air (0.4 - 0.7MPa) is introduced into the water-vapor-separation module, which consists of a stainless steel column containing polyimide membrane tubes. Water vapor permeates through the tubes and is collected by cold traps cooled with dry ice and ethanol. The module is heated with a flexible heater to control its temperature. We have determined the recovery yields under various sampling conditions and find that this system can collect atmospheric water vapor with a recovery yield of >99%. This system can thus be a useful tool for understanding short-term observations of tritium in atmospheric water vapor.
論文 続きを見る |
||||
| 4.
論文（リポジトリ） |
論文（リポジトリ）
|
Akata, Naofumi ; Shiroma, Yoshitaka ; Furukawa, Masahide ; Kato, Akemi ; Kakiuchi, Hideki ; Hosoda, Masahiro ; Kanai, Yutaka ; Yanagisawa, Fumitaka
概要:
Aerosol samples were collected at Naha, Okinawa Prefecture, Japan during July 2001 to March 2005 to elucidate the concen
…
trations of chemical components, including ^<210>Pb, present in air for a sub-tropical region of Japan. The NO^-_3, SO^<2->_4, NH^+_4 and Ca^+_2 concentrations had clear seasonal variations and were high in winter to spring and low in summer. ^<210>Pb concentrations ranged from 0.10 to 1.52 mBq m^<-3> and were low in summer and high in the other three seasons. The source of sulfur compounds in the aerosol samples was clarified by combining the sulfur isotope ratio δ^<34>S and ^<210>Pb concentrations. The multi-isotope method using δ^<34>S and ^<210>Pb concentrations was judged to be a good tool for understanding the transported sulfur source.
論文 続きを見る |
