Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 167

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

External dose estimation for wild animals using ESR spectroscopy

Oka, Toshitaka; Takahashi, Atsushi*

Hoshasen Kagaku (Internet), (110), p.13 - 19, 2020/10

The article depicts how to estimate the external exposure dose for wild animals using electron spin resonance (ESR) spectroscopy. The relationship between the CO$$_{2}$$ radical intensity and the absorbed dose, that is, dose response curve of tooth enamel of Japanese macaque was observed, and the detection limit of our method was estimated. The estimated detection limit of 33.5 mGy is comparable to the previously reported detection limit for human molar teeth. The external exposure dose for seven wild Japanese macaques captured in Fukushima prefecture were examined using this dose response curve. The estimated external exposure dose were ranged between 45 mGy to 300 mGy.

Journal Articles

A Fault dating method using an electron spin resonance

Tanaka, Kiriha*; Muto, Jun*; Nagahama, Hiroyuki*; Oka, Toshitaka

Hoshasen Kagaku (Internet), (110), p.21 - 30, 2020/10

In a fault dating by electron spin resonance (ESR), the number of unpaired electrons trapped in defects in minerals contained in a fault material is detected as ESR intensity. Based on the quantitative change of the intensity before and after an earthquake, the last age of a fault movement can be estimated. However, this method has a hypothesis called "zero-setting" which assumes the decrease in the ESR intensity to zero by fault movement during an earthquake. In order to understand and demonstrate zero-setting, the analysis of the natural fault materials and experiments mimicking fault movements have been conducted. In this paper, we summarized the previous studies about zero-setting by fault movement and described the current status and challenges.

Journal Articles

Development of lanthanide and actinide studies toward interface chemistry using vibrational sum frequency generation spectroscopy

Kusaka, Ryoji

Hosha Kagaku, (41), p.31 - 33, 2020/03

This commentary article introduced researches involved in encouragement award 2019 of the Japan Society of Nuclear and Radiochemical Sciences. Vibrational sum frequency generation (VSFG) spectroscopy and interfacial studies of solvent extraction of lanthanides and actinides using VSFG spectroscopy were described.

Journal Articles

Prediction of scintillation light yield based on track-structure simulation

Ogawa, Tatsuhiko; Sato, Tatsuhiko; Yamaki, Tetsuya*

Hoshasen Kagaku (Internet), (108), p.11 - 17, 2019/11

Scintillators are generally used to detect various kinds of particles such as electrons, gammas, protons and heavy ions. Scintillators emit photons according to the energy deposited to the crystal. It is also known that light yield is suppressed for particles depositing energy densely owing to quenching. Moreover, it is suggested that quenching is attributed to transfer of energy from excited fluorescent molecules to damaged molecules (F$"{o}$rster mechanism or Dexter mechanism). In this study, energy deposition in a scintillator crystal by radiation was calculated using radiation transport codes to finally obtain excitation and damage of fluorescent molecules. Based on the calculation, spatial configuration of exited and damaged molecules. Then the probability that F$"{o}$rster mechanism takes place in excited molecules were estimated to obtain the number of fluorescent molecules that emit photons. As a result, light yield is proportionally increased with increase in the incident energy in case of electron incidence. On the other hand, light yield is increased non-linearly in case of proton incidence. This trend is in a good agreement with the experimental results.

Journal Articles

The 20th Workshop on Environmental Radioactivity

Koarai, Kazuma

Hosha Kagaku, (40), p.26 - 27, 2019/09

Report about "The 20th Workshop on Environmental Radioactivity" was submitted in ${it hoshakagaku}$. There were 195 participants in the workshop. They actively discussed environmental radioactivity and pollution after the Fukushima-Daiichi Nuclear Power Plant. Presentation awards were given to 4 persons.

Journal Articles

Studies on incorporation of $$^{90}$$Sr and $$^{137}$$Cs in hard tissues of cattle and monkey in the Fukushima environment

Koarai, Kazuma

Hosha Kagaku, (40), p.34 - 36, 2019/09

Abstract of doctor thesis was submitted to "Hoshakagaku", which is Japanese article. I described main theme of the thesis. The hard tissues of the animals incorporated $$^{90}$$ at the development stage and bone methabolism of the tissues. On the other hand, $$^{137}$$Cs was incorporated not only the development stage but also after the stage. Strontium-90 and cesium-137 in the cattle teeth reflected the pollution after the Fukushima-Daiichi Nuclear Power Plant accident. The thesis showed $$^{90}$$ and $$^{137}$$Cs in the hard tissues would an important indicator of the environmental pollution.

Journal Articles

Effect of H$$_{2}$$O$$_{2}$$ concentration on oxidative dissolution of U$$_{2}$$O

Kumagai, Yuta

Hoshasen Kagaku (Internet), (107), p.77 - 78, 2019/04

Reaction of hydrogen peroxide (H$$_{2}$$O$$_{2}$$) with uranium dioxide (UO$$_{2}$$) oxidizes U(IV) to water-soluble U(VI). In the concept of direct geological disposal of spent nuclear fuel, this reaction is expected to induce dissolution of UO$$_{2}$$ matrix of the spent fuel. This study investigate effect of H$$_{2}$$O$$_{2}$$ concentration on the kinetics and the yield of U(VI) dissolution of this reaction. A series of experiments of the reaction of H$$_{2}$$O$$_{2}$$ with UO$$_{2}$$ powder dispersed in water has been carried out. The experimental results reveal that increase in the H$$_{2}$$O$$_{2}$$ concentration slows down the reaction and decreases the yield of U(VI) dissolution. This observation suggests that a reaction intermediate is generated in the course of the H$$_{2}$$O$$_{2}$$ reaction on the surface of UO$$_{2}$$.

Journal Articles

Recent progress of radiation physicochemical process (third part)

Kai, Takeshi; Yokoya, Akinari*; Fujii, Kentaro*; Watanabe, Ritsuko*

Hoshasen Kagaku (Internet), (106), p.21 - 29, 2018/11

It is thought to that the biological effects such as cell death or mutation are induced by complex DNA damage which are formed by several damage sites within a few nm. As the prediction of complex DNA damage at an electron track end, we report our outcomes. These results indicate that DNA damage sites comprising multiple nucleobase lesions with a single strand breaks can be formed by multiple collisions of the electrons within 1 nm. This multiple damage site cannot be processed by base excision repair enzymes. Pre-hydrated electrons can also be produced resulting in an additional base lesion over a few nm from the multi-damage site. This clustered damage site may be finally converted into a double strand break. These DSBs include another base lesion(s) at their termini that escape from the base excision process and which may result in biological effect. Our simulation is useful to reveal phenomena involved in radiation physico-chemistry as well as the DNA damage prediction.

Journal Articles

Report of participation in Radiochemical Conference

Shimada, Asako

Hosha Kagaku, (38), p.30 - 31, 2018/09

no abstracts in English

Journal Articles

Microfabrication of fluoropolymers using ion beam irradiation

Kitamura, Akane; Kobayashi, Tomohiro*

Hoshasen Kagaku (Internet), (104), p.29 - 34, 2017/10

no abstracts in English

Journal Articles

Reactivity of an antioxidant, edaravone, with reactive oxygen species and its chemical repair properties against oxidative damage on DNA

Hata, Kuniki; Lin, M.*; Yokoya, Akinari*; Fujii, Kentaro*; Yamashita, Shinichi*; Muroya, Yusa*; Katsumura, Yosuke*

Hoshasen Kagaku (Internet), (103), p.29 - 34, 2017/04

Reactivity of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), which is known to show high antioxidative properties, with oxidative species, such as hydroxyl radical ($${}^{bullet}$$OH) and azide radical (N$$^{bullet}$$$$_{3}$$), was investigated by a pulse radiolysis experiment, and generation behavior of edaravone radicals produced through these reactions were observed. It was shown that OH-adducts are produced by the reaction with $${}^{bullet}$$OH in contrast to the other oxidative radicals, which react with edaravone by an electron transfer reaction. Chemical repair properties of edaravone against DNA lesions produced by reactions of DNA with oxidative species were also investigated by a pulse radiolysis experiment with deoxyguanosine monophosphate (dGMP) and a $$gamma$$-radiolysis experiment with plasmid DNA solutions. It was observed that edaravone reduced dGMP radicals just after produced in a dilute aqueous solution and inhibited some base lesions on plasmid DNA more effectively than single strand breaks. These results show that edaravone may protect living system from oxidative stress, such as radiation, by not only scavenging oxidative species but also reducing precursors of DNA leisons.

Journal Articles

Report on the stay in Norway as a secondee of OECD Halden Reactor Project

Hata, Kuniki

Hoshasen Kagaku (Internet), (103), P. 65, 2017/04

no abstracts in English

Journal Articles

Bonding study on d- and f-block coordination compounds by combining density functional calculations with M$"o$ssbauer spectroscopic parameters

Kaneko, Masashi

Hosha Kagaku, (35), p.36 - 39, 2017/03

This paper is an article for research introduction by winner of the Japan Society of Nuclear and Radiochemical Sciences Encouragement Price 2016. It was mentioned about the achievements which revealed the spin transition behavior of iron complex and the separation mechanism of actinides from lanthanides.

Journal Articles

Recent progress of radiation physicochemical process (first part)

Kai, Takeshi; Yokoya, Akinari; Fujii, Kentaro; Watanabe, Ritsuko

Hoshasen Kagaku (Internet), (101), p.3 - 11, 2016/04

Behavior analysis of low energy electrons in liquid water provides the fundamentals for successive radiation chemistry, and it makes analysis of DNA damage implication involved in the electrons possible. We have progressed theoretical studies for radiation physicochemical process of liquid water to clear the role of low-energy secondary electrons damage to DNA. The process has included many unknown factors for the DNA damage so far. Based on the results, we implied a newly formation process of unrepair DNA damage produced by the secondary electrons assumed that it was ejected from DNA by impact of a high energy electron. We report our outcomes separately in three manuscripts entitled "Recent progress of radiation physicochemical process (first, second, third parts)" to journal of radiation chemistry. In this first part, we outline recent status of studies for the DNA damage and the radiation physicochemical process, we also show calculation method of electron impact cross sections involved strongly in electron deceleration in liquid water in the topics of our outcomes. From the calculated results, we also report our prediction, which are different from previous one, for electron thermalization.

Journal Articles

Development of Prompt Gamma-ray Analysis at J-PARC/ANNRI

Toh, Yosuke; Ebihara, Mitsuru*; Huang, M.; Kimura, Atsushi; Nakamura, Shoji; Harada, Hideo

Hosha Kagaku, (33), p.1 - 9, 2016/03

Prompt Gamma-ray Analysis (PGA) uses capture $$gamma$$ rays, which are characteristic of each particular nucleus emitted from a sample while it is being irradiated with neutrons. It has been used as a rapid, nondestructive method for performing both qualitative and quantitative multielemental analysis. Therefore, cosmochemical, environmental, archeological samples and samples from materials science and engineering are analyzed. Although, researchers have endeavored to improve the accuracy and the detection sensitivity in PGA with the coincidence and anti-coincidence methods, further improvements are possible. We developed a new analytical technique (TOF-PGA) that combines Prompt Gamma-ray Analysis (PGA) and time-of-flight elemental analysis (TOF) by using an intense pulsed neutron beam at the Japan Proton Accelerator Research Complex (J-PARC). It allows us to obtain the results from both methods at the same time. Moreover, it can be used to quantify elemental concentrations in the sample, to which neither of these methods can be applied independently, if TOF-PGA is used. TOF-PGA showed high merits, although the capability may differ in terms of the target element and coexisting elements.

Journal Articles

Recent progress of radiation physicochemical process (second part)

Kai, Takeshi; Yokoya, Akinari*; Fujii, Kentaro*; Watanabe, Ritsuko*

Hoshasen Kagaku (Internet), (102), p.49 - 56, 2016/00

Behavior analysis of low energy electrons in liquid water provides the fundamentals for successive radiation chemistry, and it makes analysis of DNA damage implication involved in the electrons possible. We have progressed theoretical studies for radiation physicochemical process of water to clear the role of secondary electrons damage to DNA. The process has included many unknown factors for the DNA damage so far. We implied a newly formation process of unrepair DNA damage produced by the secondary electrons. We report our outcomes separately in three manuscripts entitled "Recent progress of radiation physicochemical process (first, second, third parts)". In this second part, we show calculated results of thermalization lengths and times of electrons in water to verify a dynamic Monte Carlo code developed in this study. From the calculated results, we also report our prediction, which are different from previous one, for thermalization and pre-hydration processes.

Journal Articles

Pulse beam formation technique for a cyclotron

Kurashima, Satoshi

Hoshasen Kagaku (Internet), (100), p.49 - 51, 2015/10

no abstracts in English

Journal Articles

Radiation processing in my research life

Tamada, Masao

Hoshasen Kagaku (Internet), (100), P. 16, 2015/10

Collection of a rare metal form hot spring water attracted medias and had a public response by reports of numerous newspapers and television programs in my 35 years' research and development of radiation processing technologies and its technology management. Collection experiments of the rare metal were carried out in Kusatsu Onsen, Gunma prefecture, where discharge of hot spring water is the largest in Japan. We were on standby 6 am there when morning live broadcast started from 8 am. The invention of emersion grafting solved the problems in the cost reduction of adsorbent production owing to its high grafting yield and led the way for technology transfer of filter for the removal of metal ions in ppb level from semiconductor cleaning liquid and adsorbent for radio-active cesium.

Journal Articles

Current status and future prospects of ion beam breeding

Hase, Yoshihiro

Hoshasen Kagaku (Internet), (100), p.86 - 88, 2015/10

no abstracts in English

167 (Records 1-20 displayed on this page)