409 results match your criteria: "National Institute for Fusion Science[Affiliation]"
Int J Mol Sci
March 2021
Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
Cold atmospheric plasma (CAP) has attracted much attention in the fields of biotechnology and medicine owing to its potential utility in clinical applications. Recently accumulating evidence has demonstrated that CAP influences protein structures. However, there remain open questions regarding the molecular mechanisms behind the CAP-induced structural perturbations of biomacromolecules.
View Article and Find Full Text PDFSci Rep
March 2021
National Institutes of Natural Sciences, National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu, 509-5292, Japan.
Er/Dy co-doped double-clad ZBLAN optical fiber has been used to obtain amplified spontaneous emission (ASE) broadband light sources cladding-pumped by 980-nm multimode laser diode (LD) sources. It has been demonstrated that mid-infrared broadband emission extending from 2515 to 3735 nm was obtained by energy transfer between Er and Dy. We experimentally investigated the optimum design of Er/Dy co-doped ZBLAN fiber in terms of ion concentration, fiber length, pumping configuration, and pumping power.
View Article and Find Full Text PDFInt J Environ Res Public Health
January 2021
Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan.
In this study, to get a better understanding in characterizing groundwater and ensure its effective management, the radon concentrations in water samples were measured through Ryukyu limestone in southern Okinawa Island, Japan. Water samples were collected from a limestone cave (Gyokusendo cave, dropping water) and two springs (Ukinju and Komesu, spring water), and the radon concentrations were measured by liquid scintillation counters. The radon concentrations in the samples from the Gyokusendo cave, and Ukinju and Komesu springs were 10 ± 1.
View Article and Find Full Text PDFRev Sci Instrum
November 2020
Naka Fusion Institute, National Institutes for Quantum and Radiological Science and Technology, Naka, Ibaraki 311-0193, Japan.
Materials and structures of a collimator for a new neutron emission profile monitor in JT-60SA are examined through Monte Carlo simulations using the Monte Carlo N-Particle transport code. First, the shielding properties of various material combinations are compared in order to determine a combination with high shielding performances against both neutrons and gamma-rays. It is found that a collimator consisting of borated polyethylene and lead has a high shielding performance against neutrons.
View Article and Find Full Text PDFRev Sci Instrum
November 2020
Tohoku University, 6-6 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
A diamond-based neutral particle analyzer (DNPA) array composed of single-crystal chemical vapor deposition (sCVD) diamond detectors was installed on the Large Helical Device (LHD) for measuring the helically trapped energetic particles. In high neutron flux experiments, the unwanted neutron-induced pulse counting rate should be estimated using the neutron diagnostics because a diamond detector is sensitive to neutrons as well as energetic neutral particles. In order to evaluate the quantitative neutron-induced pulse counting rate on the DNPA, the response functions of the sCVD diamond detector for mono-energetic neutrons were obtained using accelerator-based D-D and D-Li neutron sources in Fast Neutron Laboratory (FNL).
View Article and Find Full Text PDFMaterials (Basel)
November 2020
HiLASE Centre, FZU-Institute of Physics of the Czech Academy of Sciences, Za Radnicí 828, 252 41 Dolní Břežany, Czech Republic.
The relatively narrow choice of magneto-active materials that could be used to construct Faraday devices (such as rotators or isolators) for the mid-infrared wavelengths arguably represents a pressing issue that is currently limiting the development of the mid-infrared lasers. Furthermore, the knowledge of the magneto-optical properties of the yet-reported mid-infrared magneto-active materials is usually restricted to a single wavelength only. To address this issue, we have dedicated this work to a comprehensive investigation of the magneto-optical properties of both the emerging (Dy2O3 ceramics and CeF3 crystal) and established (Y3Fe5O12 crystal) mid-infrared magneto-active materials.
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November 2020
Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.
The scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution.
View Article and Find Full Text PDFPhys Rev E
September 2020
Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
Magnetic reconnection in a relativistic electron magnetization regime was observed in a laboratory plasma produced by a high-intensity, large energy, picoseconds laser pulse. Magnetic reconnection conditions realized with a laser-driven several kilotesla magnetic field is comparable to that in the accretion disk corona of black hole systems, i.e.
View Article and Find Full Text PDFRev Sci Instrum
August 2020
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan.
Two new vertical neutron cameras characterized by high detection efficiency were developed on the Large Helical Device in order to observe poloidal structures of helically trapped beam ions created by the perpendicularly injected positive-ion based neutral beam (P-NB) and are newly operated since 2018. In this work, the neutron fields at the vertical neutron cameras are investigated using the Monte Carlo N-particle transport code to evaluate the performance of its collimators. The results indicate that neutrons are attenuated by the heavy concrete and are well collimated through the collimator to detectors.
View Article and Find Full Text PDFGenes (Basel)
August 2020
National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan.
Target of rapamycin (TOR) is a serine/threonine kinase that modulates cell growth and metabolism in response to environmental changes. Transfer RNA (tRNA) is an abundant and ubiquitous small non-coding RNA that is essential in the translation of mRNAs. Beyond its canonical role, it has been revealed that tRNAs have more diverse functions.
View Article and Find Full Text PDFWater Res
September 2020
National Institute for Fusion Science, 322-6, Oroshi-cho, Toki-shi, Gifu, 509-5292, Japan.
Tannic acid-type organic composite adsorbents (PA316TAS, AR-01TAS, PYRTAS, WA10TAS, WA20TAS, and WA30TAS), combined with hydrolyzed and sulfonated tannic acid (TAS) and porous-type strongly basic anion-exchange resin (PA316), benzimidazole-type anion-exchange resin embedded in high-porous silica beads (AR-01), pyridine-type anion-exchange resin (PYR), acrylic-type weakly basic anion-exchange resin (WA10), or styrene-type weakly basic anion-exchange resins (WA20 and WA30) for simultaneous removal of various kinds of radionuclides in river water were successfully synthesized. The adsorption behavior of twelve kinds of simulated radionuclides (Mn, Co, Sr, Y, Ru, Rh, Sb, Te, Cs, Ba, Eu, and I (I and IO)) on these composite adsorbents has been studied in real river water at room temperature. PA316TAS adsorbents showed much higher distribution coefficients (K) for all metal ions.
View Article and Find Full Text PDFRev Sci Instrum
February 2020
National Institute for Fusion Science, Toki, Gifu 509-5292, Japan.
Simultaneous measurement of negative ion source plasma and extracted beam is carried out in order to clarify a key plasma parameter governing the meniscus formation in negative ion sources for fusion. The plasma discharge is performed with various discharge powers at different bias voltages in order to vary the plasma parameters. It is shown that the beam width changes along the same curve with respect to the negative ion density at any bias voltage while it varies along different curves with other plasma parameters depending on the bias voltage.
View Article and Find Full Text PDFPhys Rev Lett
January 2020
Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
Rev Sci Instrum
January 2020
Tokai Rika, Co. Ltd., Oguchi 480-0195, Japan.
In this paper, we present noncontact and noninvasive vital signal detection using a microwave reflectometer. Elimination of noise components due to random movement of human subjects has been the biggest issue for microwave measurement. Appropriate filtering, amplitude control of the reflectometer signal, and cross correlation among multiple reflectometers together with new algorithms have enabled motion artifact elimination, signal peak detection, and data processing for various parameters related to heart rate (HR) and heart rate variability (HRV).
View Article and Find Full Text PDFRev Sci Instrum
January 2020
RIKEN SPring-8 Center, Hyogo 679-5148, Japan.
Positive and negative hydrogen ion reflections from surfaces by injecting singly charged hydrogen ion beams show a clear difference between atomic and molecular ion injections at low energy and grazing incidence. The intensity ratio of reflected negative to positive ions H/H increased as the incident beam energy per nucleon decreased only when molecular ion beams are injected. It implies that negative ions are more produced upon beam-surface interaction when molecules are injected.
View Article and Find Full Text PDFRev Sci Instrum
January 2020
Doshisha University, Kyotanabe, Kyoto 610-0394, Japan.
We developed a small-size electron gun capable of producing electrons with kinetic energy less than few tens of eV to investigate the slowing down and transport mechanisms of electrons in hydrogen negative ion source plasmas. The maximum extractable beam current density reached 36 μA/cm for 1 eV beam energy in a preliminary experiment. Although the present electron current density is still insufficient compared with our target value, 1 mA/cm, we have found some hints to realize larger beam current density from the electron gun through this study.
View Article and Find Full Text PDFRev Sci Instrum
January 2020
Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan.
A compact ion source that produces hydrogen plasma with an electron cyclotron resonance (ECR) configuration combined with a 2-stage extraction system with a single aperture of 6 mm diameter has been designed and built to study the performance of different materials as the plasma electrode (PE) of a negative hydrogen ion source. The source has the capability to electrically bias the PE with respect to the ECR plasma. The first experiment with low ECR power input (less than 40 W) was carried out.
View Article and Find Full Text PDFRev Sci Instrum
January 2020
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
The large RF negative hydrogen (deuterium) ion source at the ELISE test facility (half of the ITER-NBI source size) has been equipped with a Cavity Ring-Down Spectroscopy (CRDS) system, in order to measure the negative hydrogen (deuterium) ion density in the region in front of the plasma grid (first grid of the extraction system). The challenge of this diagnostic for ELISE relies on the large size of the source and therefore on the plasma length across which the measurements are performed as well as the long pulses at RF power, which can affect the cavity mirror reliability. A dedicated experiment on the mirror reliability was performed, ensuring the feasibility of measurements for long pulses (several hundred seconds) at high RF power.
View Article and Find Full Text PDFRev Sci Instrum
January 2020
Department of Fusion Science, The Graduate University for Advanced Studies, SOKENDAI, Toki, Gifu 509-5292, Japan.
Density distributions of negative hydrogen (H) ions and negative deuterium (D) ions were measured with the laser photodetachment method in the extraction region of the negative ion source. The distribution of H ion density peaks at the center of the ion source, while that of the D ion shows a flatter profile in the direction parallel to the plasma grid. The positive ion densities of hydrogen and deuterium estimated from the positive saturation current indicate similar profiles with different amounts close to the grid.
View Article and Find Full Text PDFPLoS Genet
February 2020
Laboratory of Cell Responses, National Institute for Basic Biology, Myodaiji, Okazaki, Aichi, Japan.
Accurate target recognition in transcript degradation is crucial for regulation of gene expression. In the fission yeast Schizosaccharomyces pombe, a number of meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1, and selectively degraded by the nuclear exosome during mitotic growth. Mmi1 forms nuclear foci in mitotically growing cells, and the nuclear exosome colocalizes to such foci.
View Article and Find Full Text PDFPhys Rev Lett
January 2020
Research Institute for Applied Mechanics Kyushu University, Kasuga, Fukuoka 816-8580, Japan.
The transition between isotope-mixing and nonmixing states in hydrogen-deuterium mixture plasmas is observed in the isotope (hydrogen and deuterium) mixture plasma in the Large Helical Device. In the nonmixing state, the isotope density ratio profile is nonuniform when the beam fueling isotope species differs from the recycling isotope species and the profile varies significantly depending on the ratio of the recycling isotope species, although the electron density profile shape is unchanged. The fast transition from nonmixing state to isotope-mixing state (nearly uniform profile of isotope ion density ratio) is observed associated with the change of electron density profile from peaked to hollow profile by the pellet injection near the plasma periphery.
View Article and Find Full Text PDFPhys Rev E
December 2019
Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso, Nagoya 466-8555, Japan.
Turbulence structures with the magnetic Prandtl number larger than unity are studied by means of direct numerical simulations of homogeneous, isotropic, and incompressible Hall magnetohydrodynamic (MHD) turbulence driven by a random force. Spectral and spatial structures on the scales smaller than the ion skin depth are focused upon in this numerical paper. The numerical simulations reveal the emergence of a new power law in the velocity field whereas it is not observed in MHD turbulence simulation without the Hall term.
View Article and Find Full Text PDFRev Sci Instrum
November 2019
National Institute for Fusion Science (NIFS), National Institutes of Natural Sciences, 322-6 Oroshi, Toki 509-5292, Japan.
Second deuterium operation of the negative ion based neutral beam injector was performed in 2018 in the large helical device. The electron and ion current ratio improves to I/I = 0.31 using the short extraction gap distance of 7 mm between the plasma grid (PG) and the extraction grid (EG).
View Article and Find Full Text PDFPhys Rev Lett
November 2019
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gifu 509-5292, Japan.
The isotope effect on energy confinement time and thermal transport has been investigated for plasmas confined by a stellarator-heliotron magnetic field. This is the first detailed assessment of an isotope effect in a stellarator heliotron. Hydrogen and deuterium plasmas heated by neutral beam injection on the Large Helical Device have exhibited no significant dependence on the isotope mass in thermal energy confinement time, which is not consistent with the simple gyro-Bohm model.
View Article and Find Full Text PDFSci Rep
November 2019
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, 509-5292, Japan.
The isotope effect, which has been a long-standing mystery in the turbulent magnetically confined plasmas, is the phenomena that the plasma generated with heavier hydrogen isotope show a mitigated transport. This is on the contrary to what is predicted with the simple scaling theory, in which the heavier ions easily diffuse because of its larger gyro-radius. Thanks to the newly developed analysis method and a comprehensive parameter scan experiment in the steady-state plasmas in the Large Helical Device (LHD), the isotope effect was clearly observed in the self-organized internal transport barrier (ITB) structure for the first time.
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