JOPSS - Search Results

Journal Articles

Evaluation of doped potassium concentrations in stacked two-Layer graphene using real-time XPS

Ogawa, Shuichi*; Tsuda, Yasutaka; Sakamoto, Tetsuya*; Okigawa, Yuki*; Masuzawa, Tomoaki*; Yoshigoe, Akitaka; Abukawa, Tadashi*; Yamada, Takatoshi*

Applied Surface Science, 605, p.154748_1 - 154748_6, 2022/12

https://doi.org/10.1016/j.apsusc.2022.154748

Times Cited Count：4 Percentile：48.5(Chemistry, Physical)

Immersion of graphene in KOH solution improves its mobility on SiO $_{2}$ /Si wafers. This is thought to be due to electron doping by modification with K atoms, but the K atom concentration C $_{K}$ in the graphene has not been clarified yet. In this study, the C $_{K}$ was determined by XPS analysis using high-brilliance synchrotron radiation. The time evolution of C $_{K}$ was determined by real-time observation, and the C $_{K}$ before irradiation of synchrotron radiation was estimated to be 0.94%. The C 1s spectrum shifted to the low binding energy side with the desorption of K atoms. This indicates that the electron doping concentration into graphene is decreasing, and it is experimentally confirmed that K atoms inject electrons into graphene.

Journal Articles

Local structure and phase transitions of KNbO

Yoneda, Yasuhiro; Ohara, Koji*; Nagata, Hajime*

Japanese Journal of Applied Physics, 57(11S), p.11UB07_1 - 11UB07_6, 2018/11

https://doi.org/10.7567/JJAP.57.11UB07

Times Cited Count：18 Percentile：59.6(Physics, Applied)

Local structure analysis of KNbO, which is the parent compound for lead-free piezoelectric materials, have been performed by X-ray pair-distribution functions (PDF). The refinements of local structure in wide temperature ranges indicates that only the rhombohedral structure can describe the observed bond distributions within the unit cell. The rhombohedral distortion maintained locally in all four phases.

Journal Articles

Decomposition of phenolic endocrine disrupting chemicals by potassium permanganate and -ray irradiation

Abe, Yasuhiro*; Takigami, Machiko; Sugino, Koji*; Taguchi, Mitsumasa; Kojima, Takuji; Umemura, Tomonari*; Tsunoda, Kinichi*

Bulletin of the Chemical Society of Japan, 76(8), p.1681 - 1685, 2003/08

https://doi.org/10.1246/bcsj.76.1681

Times Cited Count：5 Percentile：26.49(Chemistry, Multidisciplinary)

The decomposition of phenolic endocrine disrupting chemicals (P-EDCs), such as phenol, 4-butylphenol (BuP), and bisphenol A (BPA), in aqueous solutions by potassium permanganate (KMnO $_{4}$ ) was studied and its efficiency was compared with that of hydroxyl radicals (OH $^{.}$ ) generated by $^{60}$ Co -ray irradiation. Various organic acids and inorganic carbon were formed in the decomposition of P-EDCs due to either KMnO $_{4}$ or OH $^{.}$ . They were formed via direct aromatic ring cleavage in the case of KMnO $_{4}$ and OH $^{.}$ addition-substitution reactions followed by aromatic ring cleavage in the case of OH $^{.}$ . Comparing the decrease in the P-EDCs based on the number of electrons, the amount of KMnO $_{4}$ spent to completely eliminate BuP and BPA was comparable to the amount of OH $^{.}$ . Although three times more KMnO $_{4}$ was needed for phenol than OH $^{.}$ , the complete conversion of phenol into organic acids and inorganic carbon was achieved with 720M of electrons in both cases.

Journal Articles

A History of the universe continuing in our body

Sekine, Toshiaki

Jomo Shimbun, P. 9, 2003/01

This paper is written as one of the series on a news paper relevant to the Gunma Chemistry Exhibition to be held in commemoration of the 125th anniversary of the Chemical Society of Japan, telling readers that the origin of chemical elements is related to the radiation. As an example, K-40 is chosen for description of the fact that there exist natural radioactive elements. It is also mentioned that the origin of K-40 is ascribable to stars in the universe.

Journal Articles

Radiation measurement for safeguards environmental samples by imaging plate

Yasuda, Kenichiro; Sakurai, Satoshi; Gunji, Hideho; Usuda, Shigekazu

Journal of Nuclear Science and Technology, 39(Suppl.3), p.552 - 555, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875528

In order to contribute to the strengthened safeguards system based on the Program 93+2 of the IAEA, Japan Atomic Energy Research Institute (JAERI) constructed the CLEAR facility (Clean Laboratory for Environmental Analysis and Research) and is developing analytical technology for ultra trace amounts of nuclear materials in environmental samples. To avoid cross-contamination among the samples and contamination of the clean rooms, radioactive materials in the samples to be introduced into the CLEAR facility will be limited to a certain amount. For this purpose the authors have examined the feasibility of Imaging-plate method, which is a kind of autoradiography and is suitable for determination on distribution of low-level radioactivity in the samples. Preliminary examination with -ray (K-40), the linearity was obtained in the range of 0.01 - 0.2 Bq. The experiments with -ray (Sm-147) suggested the detection limit of 0.01 Bq, which was equivalent to 2 g of natural uranium. At the presentation, the results on actual environmental samples will be reported.

JAEA Reports

Experimental investigations of the effect of alkali fluids on montmorillonite, albite and quartz

JNC TN8400 2001-008, 36 Pages, 2001/03

JNC-TN8400-2001-008.pdf:2.92MB

Research on geologic disposal of high-level radioactive waste(HLW) has been underway in many countries. Bentonite exhibiting a low permeability, high swelling property and high sorption capacity for many radioelements is proposed as a buffer material in many countlies. Recently, cementitious materials are considered as candidate matelials for the geologic disposal of high-level radioactive waste. As the pH and the Ca, Na, K contents of hyperalkaline pore water from the cementitious materials are high, this hyperalkaline pore water would alter the buffer material. The main aim of this study is to investigate the effect of alkaline pore water into the bentonite. Used materials are montmorillonite, albite and quartz composing bentonite. These minerals mixed in a constant ratio (1:1wt%) made to react to distilled water and the alkali solutions (pH11-13). These studies have been conducted at temperatures of 50 - 150 $^{circ}$ C and run times of 10 - 200 day. XRD(X-ray powder diffraction) and SEM (Scanning Electron Microscopy) analyses were applied to studying the structure and quantitative data of each sample. From the result of this study, the main formed mineral of this experiment was analcime, which showed the tendency with a large amount of generation at a higher pH and temperature. Quantitative data of this study was conducted by X-ray powder diffraction method. THe order of the amount of the second analcime in each experiment is shown in the following. Montmorillonite and albite mixing test Montmorillonite test Montmorillonite and quartz mixing test Activation energies (E $_{a}$ ) using the quantitative data of each test are shown in the following. (1)Montmorillonite test : 54.9kJ/mol (2)Montmorillonite and albite mixing test : 51.9kJ/mol (3)Montmorillonite and quartz mixing test : 59.6kJ/mol

JAEA Reports

None

Fujita, Reiko*; *; Kondo, Naruhito*; Utsunomiya, Kazuhiro*

JNC TJ8420 2000-004, 41 Pages, 2000/03

JNC-TJ8420-2000-004.pdf:5.08MB

no abstracts in English

JAEA Reports

Sorption studies of plutonium on geological materials - year 2

J. A. BERRY*; M. BROWNSWORD*; D. J. ILETT*; Linklater, C. M.*; Mason, C.*; TWEED, C. J.*

JNC TJ8400 2000-060, 60 Pages, 2000/02

JNC-TJ8400-2000-060.pdf:2.95MB

Batch sorption experiments have been carried out to investigate the sorption behaviour of plutonium onto basalt and sandstone from the appropriate rock-equilibrated waters under different redox eonditions. Redox Potentials in solution were controlled by the addition of two reducing agents and one oxidising agent. Thermodynamic chemical modelling was undertaken to interpret the results. The sorption models were based on iron oxide. They adequately reproduced the data for sorption of plutonium onto sandstone, but tended to underpredict sorption onto basalt.

JAEA Reports