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Oral presentation

Radiation and thermal ageing studies of polymer materials used in cable insulation in nuclear power plants, 4; Polyvinylchloride (PVC)

Idesaki, Akira; Seguchi, Tadao*; Tamura, Kiyotoshi; Oshima, Takeshi; Shimada, Akihiko; Kudo, Hisaaki*

no journal, , 

The degradation of polyvinylchloride (PVC) of cable insulation was investigated by accelerated radiation and thermal ageing. The sheets of PVC as same formulation as cables were subjected to thermal ageing at temperature range 100-135$$^{circ}$$C and/or to radiation ageing by Co-60 $$gamma$$-rays at a dose rate of 1kGy/h in air. The degradation was evaluated by the tensile test and by the weight change. The relations between elongation at break and change of weight by loss of plasticizer were analyzed. At higher temperature, the plasticizer evaporates to cause the decay of tensile properties.

Oral presentation

Radiation and thermal ageing studies of polymer materials used in cable insulation in nuclear power plant, 5; Silicone rubber (SiR)

Shimada, Akihiko; Seguchi, Tadao*; Tamura, Kiyotoshi; Oshima, Takeshi; Idesaki, Akira; Kudo, Hisaaki*

no journal, , 

Silicone rubber (SiR) sheets with different formulation were examined on the two points, specimen's thickness and thermal and radiation combined accelerated ageing. The 0.5 and 2 mm thick sheets were aged by thermal at up to 235$$^{circ}$$C and Co-60 $$gamma$$ rays radiation with 1 kGy/h up to 800 kGy. The degradation was measured by tensile testing and gel fraction and swelling experiments. For check the distribution of degradation in depth of sheet, the 2 mm sheet sample was sliced by 0.3 mm thickness after ageing. The results indicated that the degradation progressed uniformly throughout the 2 mm thick sheet. For the ageing combination, the degradation by three different combinations was examined, that is, (a) simultaneous ageing, (b) thermal and radiation sequential ageing, and (c) radiation and thermal reversed sequential ageing. Elongation at break indicated that the order of degradation mild to severe was reverse sequential, sequential, simultaneous ageing.

Oral presentation

Dissociative ionization of ethanol in circularly-polarized intense laser fields

Akagi, Hiroshi; Itakura, Ryuji; Hosaka, Koichi*; Otobe, Tomohito; Yamanouchi, Kaoru; Yokoyama, Atsushi

no journal, , 

When a molecule is exposed to circularly-polarized laser fields, dissociation processes following ionization proceed differently from the case of linearly polarization. In the present work, ethanol molecules are irradiated with a circularly-polarized intense laser field (I = 1.4$$times$$10$$^{13}$$ W/cm$$^{2}$$, $$lambda$$ $$sim$$800 nm), and the produced electron and ion are measured in coincidence. The relative yields of C$$_{2}$$H$$_{4}$$OH$$^{+}$$, CH$$_{2}$$OH$$^{+}$$, and C$$_{2}$$H$$_{5}$$C$$^{+}$$ with respect to the parent ion are 0.36, 0.31, and 0.01, which correspond to only 0.5, 0.4, and 0.2 of those for the linear polarization with similar laser field intensity (1.7$$times$$10$$^{13}$$ W/cm$$^{2}$$), showing that the polarization change from linear to circular significantly suppresses the C-H, C-C, and C-O dissociation processes.

Oral presentation

Production of no-carrier-added $$^{177}$$Lu for radioimmunotherapy

Watanabe, Satoshi; Hashimoto, Kazuyuki; Watanabe, Shigeki; Iida, Yasuhiko*; Hanaoka, Hirofumi*; Endo, Keigo*; Ishioka, Noriko

no journal, , 

Oral presentation

PET imaging of NET expressing tumors using $$^{76}$$Br-MBBG

Watanabe, Shigeki; Hanaoka, Hirofumi*; Liang, J. X.; Watanabe, Satoshi; Iida, Yasuhiko*; Endo, Keigo*; Ishioka, Noriko

no journal, , 

Oral presentation

Analysis of plutonium isotope ratios in individual particles with ICP-MS for nuclear safeguards

Esaka, Fumitaka; Magara, Masaaki; Suzuki, Daisuke; Miyamoto, Yutaka; Lee, C. G.; Kimura, Takaumi

no journal, , 

In this study, inductively coupled plasma - mass spectrometry (ICP-MS) is applied to the analysis of plutonium isotope ratios in individual particles. Prior to the measurement, individual plutonium particles in samples are identified by using scanning electron microscope (SEM) and are transferred to each Si chip by a micro-manipulator attached to the SEM system. After removed from the SEM chamber, each particle is dissolved with HF-HNO$$_{3}$$ solution for subsequent ICP-MS analysis. As a result, the $$^{240}$$Pu/$$^{239}$$Pu plutonium isotope ratios in individual particles with the diameter of around 1 micro-meter are successfully determined with good precision. A remaining subject to be solved is the mass interferences by co-existing elements such as americium. In order to remove the interferences, we are developing methods for chemical separation of americium and plutonium, based on anion exchange and capillary electrophoresis systems.

Oral presentation

Current research activities for safeguards environmental sample analysis at JAEA

Kimura, Takaumi; Magara, Masaaki; Miyamoto, Yutaka; Esaka, Fumitaka; Lee, C. G.; Suzuki, Daisuke; Yasuda, Kenichiro; Inagawa, Jun; Shinohara, Nobuo

no journal, , 

no abstracts in English

Oral presentation

Measurement of the first ionization potential of Lr

Sato, Nozomi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi; Li, Z.; Nagame, Yuichiro; Sch$"a$del, M.; Ichikawa, Shinichi

no journal, , 

First ionization potentials (IPs) of heavy elements with atomic numbers Z $$>$$ 100 have not been determined up to now. Recently we have been developing a surface ionization type ion source to measure the IP of the heaviest actinide, lawrencium (Lr, Z = 103). The surface ionization comparison technique is a promising approach to measure the IP of Lr on an atom-at-a-time scale. We will present the status of our development for an apparatus for this measurement.

Oral presentation

Coherent correlation between dynamical alignment and angle-dependent ionization of NO in intense laser fields

Itakura, Ryuji; Hasegawa, Hirokazu*; Kurosaki, Yuzuru; Yokoyama, Atsushi; Oshima, Yasuhiro*

no journal, , 

When neutral molecules are partly ionized in intense laser fields (I$$_{0}$$ $$>$$ 35 TW/cm$$^{2}$$), a hole in the rotational wave packet of the remaining neutral NO is formed by the ionization, whose rate depends on the alignment angle of the molecular axis with respect to the laser polarization direction. Rotational state distributions of NO are experimentally observed with the spectroscopic technique and then the characteristic feature that the population at higher J levels is increased by the ionization can be identified. Numerical calculation for solving time-dependent rotational Schr$"o$dinger equations including the effect of the ionization is carried out. The numerical results suggest that NO molecules aligned perpendicular to the laser polarization direction are dominantly ionized at the peak intensity of I$$_{0}$$ = 42 TW/cm$$^{2}$$, where the multiphoton ionization is preferred rather than the tunneling ionization.

Oral presentation

Momentum correlation between a photoelectron and a fragment ion ejected from ethanol in femtosecond intense laser fields

Itakura, Ryuji; Hosaka, Koichi*; Yamanouchi, Kaoru*; Yokoyama, Atsushi

no journal, , 

In order to clarify the mechanism of dissociative ionization of ethanol in intense laser fields, the correlation maps P(E$$_{elec}$$, E$$_{ion}$$), where E$$_{elec}$$ and E$$_{ion}$$ denote kinetic energy of an electron and a fragment ion, respectively, are obtained by photoelectron-photoion coincidence momentum imaging. The kinetic energy distribution of the ions at a specific electron kinetic energy of electrons E$$_{elec}$$ are reproduced by an exponential curve of exp(-E$$_{ion}$$/E$$_{0}$$), where E$$_{0}$$ is a variable parameter, suggesting that the intramolecular energy redistribution proceeds efficiently in the course of the dissociation process after the ionization.

Oral presentation

Dissociative ionization of ethanol in intense UV laser fields studied by photoelectron-photoion coincidence momentum imaging

Itakura, Ryuji; Ikuta, Tomoya*; Hosaka, Koichi*; Akagi, Hiroshi; Yamanouchi, Kaoru*; Yokoyama, Atsushi; Kannari, Fumihiko*

no journal, , 

When ethanol molecules are irradiated with an intense UV pulse (400 nm,100 fs, I = 10 TW/cm$$^{2}$$), channel-specific photoelectron momentum images correlated with C$$_{2}$$H$$_{5}$$OH$$^{+}$$, C$$_{2}$$H$$_{4}$$OH$$^{+}$$, CH$$_{2}$$OH$$^{+}$$, and C$$_{2}$$H$$_{5}$$$$^{+}$$ show different features, suggesting that different electronic and vibrational state distributions are prepared upon the ionization for the respective product ion channels.

Oral presentation

Electrochemistry of the heaveist elements

Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Kitatsuji, Yoshihiro; Ishii, Yasuo; Sato, Tetsuya; Li, Z.; Sato, Nozomi; Kikuchi, Takahiro; Nishinaka, Ichiro; et al.

no journal, , 

Electrochemical studies of nobelium (No) and mendelevium (Md) using an electrolytic column chromatography at JAEA will be presented. The isotopes $$^{255}$$No and $$^{255}$$Md were produced in the $$^{248}$$Cm($$^{12}$$C, 5n) and $$^{248}$$Cm($$^{11}$$B, 4n) reactions, respectively, at the JAEA tandem accelerator. In the experiment of No, the oxidation of No$$^{2+}$$ to No$$^{3+}$$ in 0.1 M $$alpha$$-hydroxyisobutyric acid ($$alpha$$-HIB) was studied with comparing with the elution of Sr$$^{2+}$$ and Yb$$^{3+}$$. At the applied potential of 0.2 V, No was not eluted with $$alpha$$-HIB. This adsorption of No was the same as that of Sr$$^{2+}$$, indicating that No was bound in its stable divalent state. On the other hand, the elution of No in $$alpha$$-HIB was observed at 1.2 V at the position of Yb$$^{3+}$$, which demonstrated that No$$^{2+}$$ was successfully oxidized to No$$^{3+}$$. Reduction of Md$$^{3+}$$ to Md$$^{2+}$$ was also successfully carried out with the apparatus in 0.1 M HCl.

Oral presentation

Anion-exchange behavior of Db in HF/HNO$$_{3}$$ mixed solution using an on-line chemical apparatus

Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

We have investigated the chemical behavior of Db together with its group-5 homologues by anion-exchange chromatography in HF/HNO$$_{3}$$ mixed solution using a rapid online chemical apparatus (AIDA-II). The nuclides $$^{262}$$Db, $$^{88}$$Nb and $$^{169,170}$$Ta were produced in the $$^{248}$$Cm($$^{19}$$F, ${it 5}$n), $$^{nat}$$Ge($$^{19}$$F, ${it x}$n) and $$^{nat}$$Gd($$^{19}$$F, ${it x}$n) reactions, respectively, at the JAEA tandem accelerator. On-line anion-exchange separations of Db, Nb and Ta were performed using the AIDA-II. Thousand times of anion-exchange separations were conducted using AIDA-II. $$alpha$$ events were registered, and the $${it K_d}$$ values for Db was evaluated. From these results, the adsorption sequence Pa $$<$$ Db $$<$$ Nb $$ll$$ Ta was determined. The present result shows a notable difference in the adsorption behavior between Db and its homologue Ta. In the conference, the present status and the perspective of the aqueous chemistry of Db at JAEA will be also presented.

Oral presentation

New apparatus AIDA-II for aqueous chemistry of the heaviest elements

Tsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Tome, Hayato*; Nagame, Yuichiro

no journal, , 

Aqueous chemistry of element 105, dubnium (Db), is now being performed at JAEA. The nuclide 34-s $$^{262}$$Db is produced in the $$^{248}$$Cm($$^{19}$$F, 5n) reaction with the production rate of about 0.25 atoms per min. To obtain more accurate data with high statistics, we have developed a new device, AIDA-II (Automated Ion-exchange separation apparatus coupled with the Detection system for Alpha-spectroscopy), based on a continuous sample preparation and detection system, i.e., continuous collection and evaporation of effluent, and successive $$alpha$$-particles measurement. The sample preparation is accomplished within 20 s, and AIDA-II enables us to perform cyclic discontinuous column chromatographic separations of short-lived nuclides in aqueous solutions and automated detection of $$alpha$$-particles within a typical cycle of about 80 s. In the conference, we will present the new device and a result of $$alpha$$-particle detection in the Db experiment.

Oral presentation

Uranium collection from seawater with adsorbent prepared by radiation-induced graft-polymerization

Tamada, Masao; Kasai, Noboru; Seko, Noriaki; Shimizu, Takao*

no journal, , 

The uranium dissolved in seawater is extremely low concentration of 3.3 ppb. However, the total amount of uranium resource in seawater is 4.5 billons tons which is one thousand times of that in terrestrial ores. For uranium collection from seawater, amidoxime group was selected as a high affinity group in adsorbent. This adsorbent was synthesized by grafting of acrylonitrile and subsequent chemical treatment with hydroxylamine. The collection of uranium from seawater was performed in marine experiments at Aomori and Okinawa, Japan. In Aomori, 350 kg of the fibrous adsorbent stacks were dipped at 7 km offing of Aomori seashore. In total 9 tests over three years, 1 kg of uranium could be collected successfully as a yellow cake. A new braid type adsorbent has been developed to achieve the practical cost of uranium collection. The adsorption performance in Okinawa marine experiment indicated 1.5 g-U/kg-ad for 30 day soaking. The promising collection cost reached 25 thousand yen/kg-U which is equivalent to ${$}$96/lb-U$$_{3}$$O$$_{8}$$.

Oral presentation

Solid-phase synthesis of cyclic peptides containing p-(tri-n-butyl-stannyl)-phenylalanine residue

Tsukui, Narutaka; Yamada, Keiichi*; Watanabe, Shigeki; Hanaoka, Hirofumi*; Oku, Hiroyuki*; Endo, Keigo*; Ishioka, Noriko; Matsuo, Ichiro*

no journal, , 

Oral presentation

Application for PDT laser therapy based on composite-type optical fiberscope

Oka, Kiyoshi; Seki, Takeshi*; Komori, Yuki

no journal, , 

We developed a new minimally invasive laser device system using a composite-type optical fiberscope. The fiberscope consists of a centrally located $$phi$$0.1 mm single fiber for laser treatment and its surrounding about 9,000 ($$phi$$5 $$mu$$m/piece) fibers for diagnosis. This system enables transmission of an image and 50 W Yb: fiber laser in parallel. By applying our fiberscope to laser treatment in various medical fields, it enables acquisition of an image, laser treatment, blood flow measurement, estimate of distance only in one fiberscope. By using this device for the PDT treatments applied to such as lung and cervical cancers, we expect to spot the irradiated area selectively while looking at a lesion. In this paper, we present a composition of minimally invasive laser therapy device using $$phi$$1 mm composite-type optical fiberscope, the basics performance experiment result and an application to PDT therapy.

Oral presentation

Hydrogenation process of aluminum under high pressure and high temperature

Saito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori; Aoki, Katsutoshi

no journal, , 

Oral presentation

Improvement of thermal and mechanical properties of Poly(L-lactic acid) by blending and radiation-induced crosslinking

Tago, Takanori; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Tamada, Masao; Kudo, Hisaaki*; Katsumura, Yosuke*

no journal, , 

Poly (L-lactic acid) (PLA) derived from corn starch is now widespread with a potential to replace the conventional petroleum-derived plastics. The PLA has, however, the less thermal stability above around 60$$^{circ}$$C and impact resistance at room temperature than the conventional plastics. In this study, to improve the above-mentioned two properties of PLA, we investigated a new combination method of blending with polyamide11 (PA11) having high impact resistance, which is derived from castor oil, and then crosslinking. PLA/PA11(50/50wt%) blend with 3 phr of crosslinker irradiated to 100 kGy was formed about 80% of gel content. This sample demonstrated very little deformation above the grass transition-temperature of PLA, the melting-temperature of PLA and PA11 (ca.175$$^{circ}$$C and 185$$^{circ}$$C, respectively) by thermal-mechanical analysis. The impact value of crosslinked PLA/PA11 blend is 4.8 kJ/m$$^{2}$$. This value showed higher about 2.5 times of original PLA. Therefore, the applications of bioplastics will be expanded.

Oral presentation

Synthesis of microscopic carboxymethylcellulose hydrogels with metal ions by radiation-induced crosslinking

Nagasawa, Naotsugu; Rokita, B.*; Ulanski, P.*; Hiroki, Akihiro; Rosiak, J. M.*; Taguchi, Mitsumasa; Tamada, Masao

no journal, , 

The chemically modified polysaccharide derivatives such as carboxymethylcellulose (CMC) are soluble in water so that have been widely used in many industrial applications. Recently, the idea of synthesis of CMC microscopic gels by means of ionizing radiation has been appeared. To obtain microscopic gels with given molecular weights and sizes the selection of proper experimental conditions should be done. However, in case of diluted CMC aqueous solutions during irradiation, the degradation is the dominant process. In order to solve this problem, we investigated a new method by adding metal ions (CaCl$$_{2}$$) to CMC solution before irradiation. The Ca ions reduce interaction of the charge for CMC molecules and makes coils structure. Therefore, macroradicals formed on such the coiled polymer chains can make possible formation of inter- and intra-molecular crosslinking. Formation of microscopic gels in this system was observed. For 0.1% CMC with CaCl$$_{2}$$ at molar ratio CMC:CaCl$$_{2}$$ 1:0.5-1.25 during irradiation up to 50 kGy, the increment of Ca ions and dose decrease the particle sizes from 800 nm to 50 nm. The combination of metal ions addition and radiation-induced crosslinking caused significant synthesis of nano- and micro-meter sized carboxymethylcellulose hydrogels.

38 (Records 1-20 displayed on this page)