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Sakoda, Akihiro; Ishimori, Yuu; Hasan, Md. M.*; Jin, Q.*; Iimoto, Takeshi*
Journal of Environmental Radioactivity, 287, p.107703_1 - 107703_10, 2025/07
Building materials are one of the most important indoor radon sources, prompting research into their radon exhalation rate (JRn). Most previous studies examining these rates have relied on laboratory tests using pieces or blocks of materials such as concrete and brick. However, creating samples that mimic real cavity walls, defined as walls with a cavity between the two panels of the associated building material, has been challenging owing to structural complexities. In this study, we conducted the first long-term in situ measurement of JRn from the interior board of a common Japanese cavity wall comprising a thin gypsum board (interior wall), air/insulation, and concrete (exterior wall). Results indicated clear diurnal and seasonal variations in the observed JRn data. In general, the highest and lowest JRn values were observed in summer and winter, respectively, exhibiting the same pattern as that observed for thick solid concrete walls analyzed in our previous in situ study. Interestingly, JRn values increased during the day in summer and at night in winter, contrasting with the constant JRn value observed for the thick solid concrete walls over several days. Theoretical calculations indicated that in this case study, JRn was predominantly driven by diffusion, not by advection. These results could be explained by considering the wall thickness, radon diffusivity, and boundary conditions of radon activity concentrations. Our findings can help the selection and refinement of input parameters for radon sources when modeling the spatiotemporal dynamics of indoor radon in buildings. While this study provides new and interesting insights, it is only the first case study, underscoring the need for future in situ tests and the corresponding theoretical analyses across diverse buildings and environments.
Sakoda, Akihiro; Ishimori, Yuu; Hasan, Md. M.*; Jin, Q.*; Iimoto, Takeshi*
Atmosphere (Internet), 15(6), p.701_1 - 701_12, 2024/06
Times Cited Count:2 Percentile:50.89(Environmental Sciences)Building materials such as brick and concrete are known indoor radon (
Rn) and thoron (
Rn) sources. Most radon and thoron exhalation studies are based on the laboratory testing of pieces and blocks of such materials. To discuss if laboratory findings can be applied to a real-world environment, we conducted intensive in-situ exhalation tests on two solid concrete interior walls of an apartment in Japan for over a year. Exhalation rates of radon (
) and thoron (
) were measured by a measurement system, mainly consisting of an accumulation chamber and dedicated monitors. The indoor air temperature (
) and absolute humidity (
) were measured in parallel, and the wall-surface temperature and water content were occasionally measured. All data obtained here were investigated to reveal environmental and material-associated factors affecting exhalation from the concrete walls. There were weak correlations between
or
and T or
at one tested wall, and moderate correlations of
and strong correlations of
with
or
at the other wall. Our findings on
were consistent with those in a previous laboratory work where a concrete sample was subject to various temperatures, although a corresponding laboratory study of
could not be collected. Additionally, moderate or strong correlation between
and
was observed for both tested walls. The comparison of the measured data and theoretical calculations revealed a new issue on how much impact each process of the emanation and migration within concrete pore spaces has on radon and thoron exhalation. This study provides an insight into parameterizing radon and thoron source inputs in modeling the spatiotemporal dynamics of indoor radon and thoron.
Sakoda, Akihiro; Ishimori, Yuu; Jin, Q.*; Iimoto, Takeshi*
Applied Radiation and Isotopes, 207, p.111180_1 - 111180_8, 2024/05
Times Cited Count:3 Percentile:72.26(Chemistry, Inorganic & Nuclear)The impacts of mathematical models and associated parameters on radon (
Rn) and thoron (
Rn) exhalation rates based on in-situ testing at building interior solid walls were demonstrated to improve data analysis techniques. The results showed that the heterogeneity of their activity concentrations within the measurement system was more significant for thoron than radon. The diurnal variation in indoor radon should be considered for better data quality. In conclusion, a model should be appropriately made and selected under the purposes and accuracy requirements of the exhalation test.
Yamada, Ryohei*; Tamakuma, Yuki*; Kuwata, Haruka*; Saigusa, Yumi*; Watanabe, Yuki; Hirota, Seiko*; Jin, Q.*; Cai, Y.*
Hoken Butsuri (Internet), 58(3), p.169 - 177, 2023/11
no abstracts in English
SnSe
Ren, Q.*; Gupta, M. K.*; Jin, M.*; Ding, J.*; Wu, J.*; Chen, Z.*; Lin, S.*; Fabelo, O.*; Rodriguez-Velamazan, J. A.*; Kofu, Maiko; et al.
Nature Materials, 22(8), p.999 - 1006, 2023/08
Times Cited Count:91 Percentile:99.21(Chemistry, Physical)
;
SR studies and charge-spin percolation modelSheng, Q.*; Kaneko, Tatsuya*; Yamakawa, Kohtaro*; Guguchia, Z.*; Gong, Z.*; Zhao, G.*; Dai, G.*; Jin, C.*; Guo, S.*; Fu, L.*; et al.
Physical Review Research (Internet), 4(3), p.033172_1 - 033172_14, 2022/09
Fe(n,
)
Fe cross section from the surrogate ratio method and its effect on the
Fe nucleosynthesisYan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.
Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10
Times Cited Count:6 Percentile:29.69(Astronomy & Astrophysics)Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Kahler, A. C.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Pigni, M.*; Dunn, M.*; Leal, L.*; et al.
EPJ Web of Conferences, 146, p.02001_1 - 02001_9, 2017/09
Times Cited Count:8 Percentile:95.98(Nuclear Science & Technology)The CIELO collaboration has studied neutron cross sections on nuclides (
O,
Fe,
U and
Pu) that significantly impact criticality in nuclear technologies with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.
Deng, Z.*; Zhao, K.*; Gu, B.; Han, W.*; Zhu, J. L.*; Wang, X. C.*; Li, X.*; Liu, Q. Q.*; Yu, R. C.*; Goko, Tatsuo*; et al.
Physical Review B, 88(8), p.081203_1 - 081203_5, 2013/08
Times Cited Count:79 Percentile:91.91(Materials Science, Multidisciplinary)Long, Y.-W.*; Kawakami, Takateru*; Chen, W.-T.*; Saito, Takashi*; Watanuki, Tetsu; Nakakura, Yuta*; Liu, Q.-Q.*; Jin, C.-Q.*; Shimakawa, Yuichi*
Chemistry of Materials, 24(11), p.2235 - 2239, 2012/06
Times Cited Count:40 Percentile:71.78(Chemistry, Physical)An A-site ordered perovskite-structure oxide, LaCu
Fe
O
, shows unusual intermetallic charge transfer between the A-site Cu and the B-site Fe ions. Like temperature, pressure also induces the intermetallic charge transfer at room temperature and the compound changes from low-pressure LaCu
Fe
O
to high-pressure LaCu
Fe
O
accompanying with significant volume collapse and as well as unusual softening in bulk modulus. In addition, the material was changed from an antiferromagnetic insulator to a paramagnetic metal transition. Either by physical or chemical (cation substitution) pressure, the charge-transfer transition temperature decreases, and the lower volume phase stabilizes Cu
and Fe
at the A and B sites, respectively.
Deng, Z.*; Jin, C. Q.*; Liu, Q. Q.*; Wang, X. C.*; Zhu, J. L.*; Feng, S. M.*; Chen, L. C.*; Yu, R. C.*; Arguello, C.*; Goko, Tatsuo*; et al.
Nature Communications (Internet), 2, p.1425_1 - 1425_5, 2011/08
Times Cited Count:174 Percentile:93.71(Multidisciplinary Sciences)In a prototypical ferromagnet (Ga,Mn)As based on a III-V semiconductor, substitution of divalent Mn atoms into trivalent Ga sites leads to severely limited chemical solubility and metastable specimens available only as thin films. The doping of hole carriers via (Ga,Mn) substitution also prohibits electron doping. To overcome these difficulties, Masek et al. theoretically proposed systems based on a I-II-V semiconductor LiZnAs, where isovalent (Zn,Mn) substitution is decoupled from carrier doping with excess/deficient Li concentrations. Here we show successful synthesis of Li
(Zn
Mn
)As in bulk materials. We reported that ferromagnetism with a critical temperature of up to 50 K is observed in nominally Li-excess compounds, which have p-type carriers.
Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Times Cited Count:52 Percentile:70.05(Biochemistry & Molecular Biology)Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
Sakoda, Akihiro; Ishimori, Yuu; Hasan, Md. M.*; Jin, Q.*; Iimoto, Takeshi*
no journal, ,
no abstracts in English
Jin, Q.*; Sakoda, Akihiro; Iimoto, Takeshi*
no journal, ,
Radon-222, a gaseous decay product in the Uranium decay chain, has been recognized as a significant factor contributing to lung cancer and has also been widely used as a tracer for environmental monitoring. Extensive research has focused on understanding its behavior in the environment along with the measurement technique. Regarding previous research on Radon exhalation rate from the soil, various influence factors such as temperature, air pressure, humidity, soil conditions, and soil water contents have been studied extensively. For in-situ continuous measurement of Radon exhalation rate from the soil, the simplest set-up is the long-term coverage of an accumulation chamber on a soil surface to collect Radon gas from the soil. This may impact the environmental parameters such as the temperature of soil and air in the chamber, and soil conditions including soil water contents and humidity, potentially leading to differences in Radon exhalation rate measurement results between the soil surface in and around the chamber. To investigate the effects of the long-term coverage on the same soil surface on measurement results, an in-situ measurement method based on the open-loop accumulation chamber technique has been obtained for comparing the environmental parameters and the Radon exhalation rates between continuous measurement and spot measurement. This research can provide the Radon exhalation mechanism regarding the change of the environmental parameters, especially during the measurement using the accumulation chamber technique, to decrease the potential effects caused by the variation of influence factors, improving the accuracy of Radon exhalation rate measurement results.
Sakoda, Akihiro; Ishimori, Yuu; Hasan, Md. M.*; Jin, Q.*; Kanzaki, Norie; Iimoto, Takeshi*
no journal, ,
Building materials such as brick and concrete are known to be one of indoor radon (Rn-222) and thoron (Rn-220) sources. Most radon and thoron exhalation studies have been based on laboratory tests using pieces and blocks of such materials. To elucidate how laboratory findings can be used in a real-world environment, we conducted intensive in-situ radon and thoron exhalation tests on interior walls, with different structure types of an apartment (i.e., solid wall and cavity wall) for over a year. This study provides an insight into parameterizing a radon source input in modeling the spatial and temporal dynamics of indoor radon and thoron air concentrations.