Showing papers by "Japan Atomic Energy Research Institute published in 2009"
TL;DR: In this article, the spectral lines and energy levels of multiply ionized tungsten atoms, W2+ through W73+, have been compiled Experimental data on spectral lines, energy levels and spectral lines exist for the spectra of W III through W VII, W XXVIII through W LI, W LIII, and W LV through LXV.
167 citations
TL;DR: A series of ternary compounds RCu 2 Si 2 (R: rare earth) has been grown in single-crystalline form by the flux method as mentioned in this paper, and the magnetic properties of these compounds were investigated by measuring the lattice parameter, electrical resistivity, magnetic susceptibility, and magnetization.
Abstract: A series of ternary compounds RCu 2 Si 2 (R: rare earth) has been grown in single-crystalline form by the flux method The magnetic properties of these compounds were investigated by measuring the lattice parameter, electrical resistivity, magnetic susceptibility, and magnetization All the compounds crystallize in the tetragonal ThCr 2 Si 2 -type structure Most of these compounds order antiferromagnetically at low temperatures, except when R=Y, La, Yb, and Lu The magnetic anisotropy in the susceptibility and magnetization at low temperatures is found to be relatively small despite the tetragonal crystal structure An increase in the electrical resistivity just below the ordering temperature and a first-order-like transition are characteristic features of RCu 2 Si 2 with R = light rare earth and R = heavy rare earth, respectively
42 citations
TL;DR: In this article, the authors report on a pressure-induced evolution of magnetism and superconductivity in a helical magnet with an incommensurate wave vector under pressure.
Abstract: We report on a pressure $(P)$-induced evolution of magnetism and superconductivity (SC) in a helical magnet ${\text{CeRhIn}}_{5}$ with an incommensurate wave vector ${Q}_{i}=(\frac{1}{2},\frac{1}{2},0.297)$ through the $^{115}\text{I}\text{n}$ nuclear quadrupole resonance (NQR) measurements under $P$. Systematic measurements of the $^{115}\text{I}\text{n}$-NQR spectrum reveal that the commensurate antiferromagnetism (AFM) with ${Q}_{c}=(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ is realized above ${P}_{m}\ensuremath{\sim}1.7\text{ }\text{GPa}$. An important finding is that the size of SC gap and ${T}_{c}$ increase as the magnitude of the AFM moment decreases in the $P$ region, where SC uniformly coexists with the commensurate AFM. This result provides evidence of strong coupling between the commensurate AFM order parameter (OP) and SC OP.
31 citations
TL;DR: BNCT can be applied to malignant brain tumors in children, especially under 3 years instead of conventional radiation, although it can achieve the local control in the primary site, it cannot prevent CSF dissemination in patients with glioblastoma.
26 citations
01 Jun 2009
TL;DR: In this article, a complete neutronic analysis has been performed for the current design of the JT-60SA toroidal field coil (TFC) system, assuming a DD neutron emission rate of 1.5×1017 n/s (and 1% DT).
Abstract: In the present study a complete neutronic analysis has been performed for the current design of the JT-60SA toroidal field coil (TFC) system. The MCNP5 Monte Carlo code has been used to calculate the nuclear heating, neutron spectra and absorbed dose in the TFC components, assuming a DD neutron emission rate of 1.5 × 1017 n/s (and 1% DT). Nuclear heating of the winding pack is lower than 0.3 mW/cm3 and the maximum nuclear heating of the TFC case is 0.4 mW/cm3. The overall nuclear heating, including the safety margin, is less than 8 kW. Spatial distribution of the nuclear heating has been provided along poloidal, radial and toroidal directions as to be used for thermo-hydraulic analysis and the design of TFC system. The absorbed dose to insulator is as low as to avoid the replacement during the whole life of the machine. Neutron fluxes have been used as input for a preliminary activation analysis performed with FISPACT inventory code. Activity and contact dose rates have been calculated at different cooling times, after 10 years of operations in some representative zone of the winding pack and the case. All the TFC materials can be easily recycled within the first day after shutdown and the hands-on recycling is possible within less than 30 years.
22 citations
21 Feb 2009-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the authors measured the neutron powder-diffraction data of apatite-type La-silicate La 9.50 Si 6 O 26.25, using JAEA-HRPD diffractometer at 10 K. The obtained cell parameters were a =0.971297(7)nm, and c = 0.717950(6)nm.
Abstract: The neutron powder-diffraction data of the apatite-type La-silicate La 9.50 Si 6 O 26.25 , was measured using JAEA-HRPD diffractometer at 10 K. The Rietveld refinement on the basis of hexagonal P6 3 / m was successfully carried out with anisotropic thermal displacement parameters for all sites. The obtained cell parameters were a =0.971297(7) nm, and c =0.717950(6) nm. On the Rietveld refinement supported by maximum entropy method, the interstitial oxygen positions show randomly distribution around La2 site, and they may give the driving-force of high ionic conductivity to the main ionic conduction site O4.
21 citations
TL;DR: In situ synchrotron X-ray diffraction experiments have been conducted on CaSiO3 perovskite (CaPv) in a double-stage multianvil apparatus up to 18 GPa and 1600 K using a newly developed step-scan diffraction technique as discussed by the authors.
19 citations
TL;DR: In this article, a review of recent studies on glassy dynamics and glass transition of polymer thin films using neutron and X-ray reflectivity and inelastic neutron techniques is presented.
Abstract: We review our recent studies on glassy dynamics and glass transition of polymer thin films using neutron and X-ray reflectivity and inelastic neutron techniques. In the last decade extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties such as reduction in the glass transition temperature T g with film thickness and negative thermal expansivity for thin films below about 25 nm, and often some contradictory experimental results have been reported. It is believed that a key to solve the controversial situation is to disclose heterogeneous structure or multi-layer structure in polymer thin films. In the review, therefore, we summarize our recent experimental results by neutron and X-ray reflectivity and inelastic neutron scattering, focusing on the dynamic heterogeneity in polymer thin films.
18 citations
TL;DR: The development of improved microcapsules that were prepared using calcium- and yttrium-induced polymerization exhibited a synergistic antitumor effect combined with 2-Gy irradiation and were associated with reduced adverse effects.
Abstract: Purpose Radiation-sensitive microcapsules composed of alginate and hyaluronic acid are being developed. We report the development of improved microcapsules that were prepared using calcium- and yttrium-induced polymerization. We previously reported on the combined antitumor effect of carboplatin-containing microcapsules and radiotherapy. Methods and Materials We mixed a 0.1% (wt/vol) solution of hyaluronic acid with a 0.2% alginate solution. Carboplatin (l mg) and indocyanine green (12.5 μg) were added to this mixture, and the resultant material was used for capsule preparation. The capsules were prepared by spraying the material into a mixture containing a 4.34% CaCl 2 solution supplemented with 0–0.01% yttrium. These capsules were irradiated with single doses of 0.5, 1.0, 1.5, or 2 Gy 60 Co γ-rays. Immediately after irradiation, the frequency of microcapsule decomposition was determined using a microparticle-induced X-ray emission camera. The amount of core content released was estimated by particle-induced X-ray emission and colorimetric analysis with 0.25% indocyanine green. The antitumor effect of the combined therapy was determined by monitoring its effects on the diameter of an inoculated Meth A fibrosarcoma. Results Microcapsules that had been polymerized using a 4.34% CaCl 2 solution supplemented with 5.0 × 10 −3 % (10 −3 % meant or 10% −3 ) yttrium exhibited the maximal decomposition, and the optimal release of core content occurred after 2-Gy irradiation. The microcapsules exhibited a synergistic antitumor effect combined with 2-Gy irradiation and were associated with reduced adverse effects. Conclusion The results of our study have shown that our liquid core microcapsules can be used in radiotherapy for targeted delivery of chemotherapeutic agents.
16 citations
TL;DR: In this article, the quadrupole collective oscillations in the bose-fermi mixtures of ultracold atomic gases of Yb isotopes were studied, and the results were shown to be consistent with the results obtained in the small amplitude approximations as the random phase approximation in early stage of oscillation, but, in later stage, these two approaches gave the different results.
Abstract: We study quadrupole collective oscillations in the bose-fermi mixtures of ultracold atomic gases of Yb isotopes, which are realized by Kyoto group. Three kinds of combinations are chosen, 170 Yb− 171 Yb , 170 Yb− 173 Yb and 174 Yb− 173 Yb , where boson-fermion interactions are weakly repulsive, strongly attractive and strongly repulsive respectively. Collective oscillations in these mixtures are calculated in a dynamical time-evolution approach formulated with the time-dependent Gross-Pitaevskii and the Vlasov equations. The boson oscillations are shown to have one collective mode, and the fermions are shown to have the boson-forced and two intrinsic modes, which correspond to the inside- and outside-fermion oscillations for the boson-distributed regions. In the case of the weak boson-fermion interactions, the dynamical calculations are shown to be consistent with the results obtained in the small amplitude approximations as the random phase approximation in early stage of oscillation, but, in later stage, these two approaches are shown to give the different results. Also, in the case of the strong boson-fermion interactions, discrepancies appear in early stage of oscillation. We also analyze these differences in two approaches, and show that they originated in the change of the fermion distributions through oscillation.
15 citations
TL;DR: A novel pathway for the transformation from highly oriented pyrolytic graphite foils into amorphous diamond platelets is reported, which consists of three stages of neutron irradiation, shock compression, and rapid quenching.
Abstract: We report the discovery of a novel pathway for the transformation from highly oriented pyrolytic graphite foils into amorphous diamond platelets. This pathway consists of three stages of neutron irradiation, shock compression, and rapid quenching. We obtained transparent platelets which show photoluminescence but no diamond Raman peak, similar to the case of amorphous diamond synthesized from C60 fullerene. Wigner defects formed by irradiation are considered to make a high density of diamond nucleation sites under shock compression, of which growth is suppressed by rapid quenching.
TL;DR: In this article, the effect of defects/impurities, growth process, off-stoichiometry and presence of impurity phases on the superconducting properties of noncentrosymmetric CePt3Si is analyzed by means of the temperature dependence of the magnetic penetration depth.
Abstract: We report a study in which the effect of defects/impurities, growth process, off-stoichiometry and presence of impurity phases on the superconducting properties of noncentrosymmetric CePt3Si is analysed by means of the temperature dependence of the magnetic penetration depth. We found that the linear low-temperature response of the penetration depth—indicative of line nodes in this material—is robust regarding sample quality, in contrast to what is observed in unconventional centrosymmetric superconductors with line nodes. We discuss evidence suggesting that the broadness of the superconducting transition may be intrinsic, though not implying the existence of a second superconducting transition. The superconducting transition temperature systematically occurs at about 0.75 K in our measurements, in agreement with resistivity and ac magnetic susceptibility data but in conflict with specific heat, thermal conductivity and NMR data in which Tc is about 0.5 K. Random defects do not change the linear low-temperature dependence of the penetration depth in the heavy-fermion CePt3Si with line nodes, as they do in unconventional centrosymmetric superconductors with line nodes.
TL;DR: In this paper, the electronic structure of hexagonal boron nitride (h-BN) epitaxial thin film on Ni(1.1) substrate was analyzed by density functional theory calculations with some model clusters.
TL;DR: The results indicate that >20 ATP‐binding protein superfamilies have been invented independently in the process of molecular evolution, and the conservative evolutionary diffusion of global folds and functions is the origin of the relationship between them.
Abstract: Superfamily classifications are based variably on similarity of sequences, global folds, local structures, or functions. We have examined the possibility of defining superfamilies purely from the viewpoint of the global fold/function relationship. For this purpose, we first classified protein domains according to the β-sheet topology. We then introduced the concept of kinship relations among the classified β-sheet topology by assuming that the major elementary event leading to creation of a new β-sheet topology is either an addition or deletion of one β-strand at the edge of an existing β-sheet during the molecular evolution. Based on this kinship relation, a network of protein domains was constructed so that the distance between a pair of domains represents the number of evolutionary events that lead one from the other domain. We then mapped on it all known domains with a specific core chemical function (here taken, as an example, that involving ATP or its analogs). Careful analyses revealed that the domains are found distributed on the network as >20 mutually disjointed clusters. The proteins in each cluster are defined to form a fold-based superfamily. The results indicate that >20 ATP-binding protein superfamilies have been invented independently in the process of molecular evolution, and the conservative evolutionary diffusion of global folds and functions is the origin of the relationship between them.
TL;DR: In this article, it was shown that upper term labels for the 4f(F5=2)4p 5f (5/2,5/ 2)1 and (5 2,7/2)1 were, by mistake, interchanged in the line list.
TL;DR: In this article, polymethylsilsesquioxane (PMSQ) fiber was exposed to metal chloride vapors in a controlled atmosphere or electron beam irradiation in air to promote the curing process.
Abstract: Polymethylsilsesquioxane (PMSQ) fiber was exposed to metal chloride vapors in a controlled atmosphere or electron beam irradiation in air to promote the curing process. The cured fibers were pyrolyzed at 1273K to compare the efficiency of individual curing method. The cured fibers were investigated by FT-IR, an optical microscope and TG analysis. In the case of successful curing, averaged diameter and tensile strength were analyzed on the obtained Si-O-C fibers.
TL;DR: It is concluded that acid soil-tolerance is closely associated with leaf water relations in rice plants, resulting in higher growth rate in the acid-tolerant varieties, when plants were exposed to the acid solution conditions.
Abstract: The visual symptoms of damage by acid sulfate soil look quite similar to those due to soil moisture deficit. The present paper is to confirm if acid soil-tolerance is associated with drought tolerance in terms of leaf water potential, transpiration, and dry matter production. Seedlings of seven acid soil-tolerant (acid-tolerant), and three acid soil-intolerant varieties (acid-intolerant) were subjected to low pH conditions (pH 3.8) for 48 hours. The rate of water uptake was determined continuously by measuring radioactivity in the collar part (target area) of rice leaves exposed to 18F-labeled water (18F-water) using a Positron Emitting Tracer Imaging System (PETIS). The PETIS measurement showed that the radioactivity in the target position of leaves of acid-tolerant varieties increased faster than that of the intolerant varieties after the 18F-water was applied into the vial. In the plants subjected to low pH conditions, the transpiration rate (Tr) and leaf water potential (Ψ) decreased in both acid-tolerant and intolerant varieties. However, the extent of reduction was less in the acid-tolerant varieties than in the intolerant ones. Moreover, the dry matter production rate of the acid-tolerant varieties was significantly higher than that of the acid-intolerant ones in the low pH conditions. This study clearly shows that 18F-water uptake in a leaf was higher, and water relations were also better maintained in the acid-tolerant varieties compared with intolerant ones, resulting in higher growth rate in the acid-tolerant varieties, when plants were exposed to the acid solution conditions. We conclude that acid soil-tolerance is closely associated with leaf water relations in rice plants.
TL;DR: In this paper, the effect of PMHS additives with different chemical and physical natures on the obtained pore structures, because PMHS decomposition process played a role of hydrogen gas source.
Abstract: Silicon carbide (SiC) based fibers with continuous pore structures were synthesized by the precursor method using a polycarbosilane (PCS) and polymethylhydrosiloxane (PMHS) polymer blends. The pore formation process can be explained by hydrogen gas dissolution in the polymer melt and desaturation process of the dissolved gas during the fiber spinning. We investigated the effect of PMHS additives with different chemical and physical natures on the obtained pore structures, because PMHS decomposition process played a role of hydrogen gas source. The individual polymer melts were characterized by viscosity measurement, gas chromatograph analysis and thermogravimetric (TG) analysis in order to obtain details of pore structure control.
21 Feb 2009-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, three neutron resonance spin echo spectrometers were installed in the No. 17 beam port of JSNS to create very low background levels of neutron and gamma rays in the experimental area.
Abstract: It is planned that three neutron resonance spin echo spectrometers will be installed in the No. 17 beam port of JSNS. In order to install these three spectrometers in one beam port, the neutron incident beam system to be installed in No. 17 port cannot only supply three polarized neutron beams to these spectrometers, but should also create very low background levels of neutron and gamma rays in the experimental area. We report based on shield evaluations how to realize the low background level by using two highly curved neutron guide tubes with high quality supermirrors.
07 Jun 2009
TL;DR: In this article, a thin-film InGaP/GaAs dual-junction (TF2J) solar cell was used to study the radiation resistance of the TF2J cells with efficiency of 20-23% under AM0, 1sun at 25°C.
Abstract: Thinned III–V multi-junction solar cells can realize the advantages of being high-efficiency and light-weight, as such these cells meets the requirement for higher W/kg and W/m3 solar panels. Here we report the development results of a thin-film InGaP/GaAs dual-junction (TF2J) solar cell. In this paper, we study the radiation resistance of the TF2J cells with efficiency of 20–23% under AM0, 1sun at 25°C. The cells were subjected to proton irradiation with an energy range of 100keV–10MeV. The results were compared with the radiation resistance of a conventional InGaP/GaAs/Ge triple-junction (3J) cell. In the proton energy range of 200–400keV, radiation resistance of the TF2J cell is superior to that of the 3J cell. Particularly, the Isc of the TF2J cell is significantly higher than that of the 3J cell after exposure to 380keV and 1MeV protons, which results in higher remaining factor of Pmax for the TF2J cell. In addition, Voc of the cells after the irradiations are almost equivalent, even though the TF2J cell is a dual-junction structure. The higher Isc of the TF2J cell after irradiation is due to higher radiation resistance of the GaAs sub-cell according to EQE comparison.
TL;DR: In this article, the inside residual stress of carburizing-nitriding quenching spur gear measure was analyzed using the neutron diffraction method in respect of residual stress.
Abstract: The purpose of this paper is coming thing by the neutron diffraction method in respect of inside residual stress of carburizing-nitriding quenching spur gear measure. Moreover, from Metallo-thermo-mechanical theory, simulation using the coupled analysis by finite element method is carried out, and the residual stress is predicted.
TL;DR: In this article, a phase diagram for antiferromagnetic spin fluctuations in the paramagnetic state at 0 was presented, showing that the superconducting order occurs in the range 1.36--1.84 GPa.
Abstract: We present a phase diagram for the antiferromagnetism and superconductivity in ${\text{Ce}}_{2}{\text{RhIn}}_{8}$ probed by In-NQR studies under pressure $(P)$. The quasi-two-dimensional character of antiferromagnetic spin fluctuations in the paramagnetic state at $P=0$ evolves into a three-dimensional character because of the suppression of antiferromagnetic order for $Pg{P}_{\text{QCP}}\ensuremath{\sim}1.36\text{ }\text{GPa}$ (QCP: quantum critical point). Nuclear-spin-lattice relaxation rate $1/{T}_{1}$ measurements revealed that the superconducting order occurs in the $P$ range 1.36--1.84 GPa, with maximum ${T}_{c}\ensuremath{\sim}0.9\text{ }\text{K}$ around ${P}_{\text{QCP}}\ensuremath{\sim}1.36\text{ }\text{GPa}$.
01 Mar 2009
TL;DR: In this article, the magnetization data from vibrating sample magnetometer in a single crystal of CeRu2 was analyzed and it was shown that magnetization profile is dipolar like only at very low fields and as the applied field increases it gets drastically modified.
Abstract: Long ago S. B. Roy and co-workers had explored the appearance of anomalous paramagnetic response in the magnetization data near the HC2 phase boundary in samples of CeRu2. Recently, an anomalous paramagnetic response has also been demonstrated in a Boro-carbide superconductor LUM2B2C, where the phenomenon has been related to the symmetry transition of the flux line lattice. We report here the magnetization data from vibrating sample magnetometer in a single crystal of CeRu2. We demonstrate that the magnetization profile is dipolar like only at very low fields and as the applied field increases it gets drastically modified. The presence of quadrupole moment along with the dipole moment is needed to justify such a magnetization profile. We report that the quadrupole moment undergoes a large modulations near the HC2 phase boundary. Hence, there is a possibility of response from quadrupole moment getting mixed with that from dipolar response which might lead to paramagnetic anomaly prior to Hc2.
Seoul National University1, Osaka University2, KEK3, Osaka Electro-Communication University4, Tohoku University5, Ewha Womans University6, Korea Research Institute of Standards and Science7, Kyoto University8, University of Tokyo9, Tokyo Institute of Technology10, Japan Atomic Energy Research Institute11
TL;DR: In this article, it was shown that the universal quenching of nucleon yields from the prediction of one-nucleon induced (1N-) NMWD can be explained by a fairly large contribution of the three-body process (Γ2N) in Γnm.
Abstract: The long standing Γn/Γp puzzle of NMWD has finally been solved recently. It appears that the reason behind the puzzle was the universal quenching of nucleon yields from the prediction of one-nucleon induced (1N-) NMWD. We have shown that the quenching of nucleon yields can be explained only when we include a fairly large contribution of the three-body process (Γ2N) in Γnm.
TL;DR: In this paper, the decay constant of uranium glass was found to decrease gradually from 265 μs at RT to 24 µs at 282°C, with the magnetic moment of 6.48 to 8.24 Bohr magneton in the temperature range of 2 K to 300 K.
Abstract: Temperature dependence of time resolved photoluminescence at 512 and 528 μm of uranium glass showed that the decay constant decreased gradually from 265 μs at RT to 24 μs at 282°C. On the other hand, magnetization measurements of the uranium glass showed the paramagnetic behavior with the magnetic moment of 6.48 to 8.24 Bohr magneton in the temperature range of 2 K to 300 K, from which the electronic configuration of U in uranium glass seems to be 5f36d1 or 5f26d2.