K Tanaka

Publications (52)51 Total impact

• Article: Performance of compact liquid helium free 3He-4He dilution refrigerator directly coupled with GM cooler in TES microcalorimeter operation

  T Umeno, Y Kamioka, S Yoshida, K Maehata, K Ishibashi, K Takasaki, K Tanaka
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  ABSTRACT: A superconducting transition edge thermosensor (TES) microcalorimeter was cooled by a compact liquid-helium-free 3He-4He dilution refrigerator with loading a Gifford-McMahon (GM) cooler for detection of LX-ray photons emitted from an 241Am source. The first and second stages of the GM cooler are directly coupled with the first and the second precool heat exchangers of a stick shaped dilution unit through copper plates in the vacuum chamber, respectively. The circulating 3He-4He gas through the precooled heat exchangers is condensed into a liquid of condense mixture by the isoenthalpic expansion through the Joule-Thomson impedance. A cascade of two mixing chambers are employed for achieving sufficient cooling power. The helium-free dilution refrigerator performs the cooling power of 20 μW at 100 mK. The TES and SQUID chips suffered from mechanical vibrations induced by a reciprocating motion of the displacer of the GM cooler. Detection signals of LX-ray photons emitted from 241Am source were observed by operating the TES microcalorimeter in severe noise environment induced by mechanical vibrations.
  Journal of Physics Conference Series 03/2009; 150(1):012051.
• Article: Developments of an Adaptive Stereoscopic‐Piv System For The Analyses Of The Flow‐Structure Interactions(Fsi) Of Air‐Lifted Bodies

  D. H. Doh, T. G. Hwang, H. J. Jo, M. Takei, K. Tanaka, T. Uemura
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  ABSTRACT: An adaptive stereoscopic‐PIV system has been constructed for flow analyses around a cylinder body (length=60mmm, diameter=10mm, polystyrene). The body is floated by the swirling flows in a vertical pipe with a length of 600mm and an inner diameter of 100mm. Four optical sensors(LEDs) were installed onto the pipe wall to detect the posture of the cylinder body. The constructed stereoscopic‐PIV system is activated by the signals of the optical sensors when the cylinder is in upright posture. The measurement system consists of two cameras, a Nd‐Yag laser and a host computer. Flow characteristics around the floating cylinder body and the motional characteristics of the body itself are investigated when the body becomes upright posture. It has been verified that the motion of the floating cylinder becomes stable when the azimuthal velocity component of the swirl flow is maintained at stable states. © 2007 American Institute of Physics
  AIP Conference Proceedings. 06/2007; 914(1):514-522.
• Article: Application of Pb‐doped CaGa2S4 as a fluorescent light

  Y. Okubo, T. Dohashi, T. Shidara, K. Tanaka, H. Uchiki
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  ABSTRACT: Pb-doped CaGa2S4 powder-dispersed resin was spread on a glass plate and a flat panel fluorescent lamp excited by UV-LEDs was fabricated. The device showed yellow-red luminescence. Under black light excitation of 352 nm, the device emitted yellow luminescence. An attempt was made to obtain white luminescence by mixing Ce-doped CaGa2S4 powder with Pb-doped CaGa2S4 powder. But the blue-green luminescence was still weak and other blue luminescent materials for mixing are necessary. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
  physica status solidi (c) 08/2006; 3(8):2746 - 2749.
• Article: Donor‐acceptor pair recombination luminescence from Cu2ZnSnS4 bulk single crystals

  K. Tanaka, Y. Miyamoto, H. Uchiki, K. Nakazawa, H. Araki
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  ABSTRACT: Photoluminescence from Cu2ZnSnS4 bulk single crystals was studied as a function of temperature and excitation power density. The bulk single crystals showed a broad luminescence between 1.1 and 1.45 eV. The peak energy of the photoluminescence was shifted to higher energy side when the excitation power density was increased. The origon of the photoluminescence was attributed to donor–acceptor pair recombination with an activation energy of 48 meV. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
  Physica Status Solidi (A) Applications and Materials 08/2006; 203(11):2891 - 2896. · 1.46 Impact Factor
• Article: Mechanism of the anodic bonding between PZT ceramics and silicon wafer

  G Sasaki, H Fukunaga, T Suga, K Tanaka
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  ABSTRACT: The anodic bonding temperature of silicon wafer and lead zirconate titanate oxide (PbZrxTi1-xO3;PZT) ceramics is decreased from 500 degrees C to 450 degrees C by coating aluminum on the electrode site of PZT surface. During the anodic bonding process, the sodium oxides in the glass decompose into sodium ions and oxygen ions. The sodium in the glass layer migrates to the PZT/glass interface and reacts with PZT ceramics and glass to form some sodium-containing spherical-like crystalline precipitates. The gaps caused by touching of the silicon wafer and glass layer on PZT ceramics are lost by oxygen migration and silicon oxidation. (C) 1997 Elsevier Science S.A.
  Materials Chemistry and Physics 01/1997; 51(2):174-177. · 2.23 Impact Factor
• Article: Photoinduced anisotropic conversion of bonding and lone-pair electrons in As_ {2} S_ {3} sglass

  A. V. Kolobov, V. Lyubin, T. Yasuda, K. Tanaka
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  ABSTRACT: We present the results of a study of photoinduced anisotropy in a model chalcogenide glass As2 S3 in a wide spectral range using reflectance-difference spectroscopy. We have found that the anisotropy is induced at energies much exceeding the energy of the inducing photons and that the sign of the photoinduced anisotropy is opposite at smaller and higher energies. To explain the results, we suggest a model considering redistribution between bonding and lone-pair electrons.
  Phys. Rev. B. 12/1996; 55(1).
• Article: Measurement of the 2-dimensional electric field vector in dielectric liquids

  K. Tanaka, T. Takada
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  ABSTRACT: A new measurement technique for two-dimensional electric field vectors (electric field intensity and its direction) in liquid dielectrics has been developed in this study. The theoretical equation for measuring the electrical field vector is derived for the optical system which consists of a He-Ne laser, polarizer, quarter-wave plate, test cell with nonuniform electric field, nonpolarizing beam splitter, two analyzers and two photo detectors. The effectiveness of the technique is confirmed by comparing the theoretical values and experimental results. Furthermore, the nonuniform electric field vector distributions of the transformer oil in a compound insulation system of liquids and solids are measured
  IEEE Transactions on Dielectrics and Electrical Insulation 09/1994; · 1.09 Impact Factor
• Article: Localizing nature of photo-excited states in SrTiO3

  T Hasegawa, M Shirai, K Tanaka
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  ABSTRACT: The absorption and luminescence measurements of SrTiO3 are made between room temperature and 10 K. From the absorption spectra, it is shown that this material has an indirect band gap energy of 3.16 eV at 10 K. No exciton absorption is observed. The luminescence spectra indicate the existence of STE. A time-resolved luminescence measurements revealed that localizing of electrons and holes plays an important role in the kinetics of photo-excited states.
  Journal of Luminescence.
• Article: Temperature dependence of single-crystal elastic constants of Mo(Si,Al)2

  K. Tanaka, K. Nawata, H. Inui, M. Yamaguchi, M. Koiwa
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  ABSTRACT: The temperature dependence of single-crystal elastic constants of Mo(Si,Al)2 with the hexagonal C40 structure has been measured by the rectangular parallelepiped resonance method over the temperature range from room temperature to 1373 K. The silicide has the largest value of Poisson's ratio among transition-metal silicides with the C40 structure. This is interpreted in terms of the reduced directionality in atomic bonding due to the partial substitution of Al for Si atoms. The expression of the elastic constants on the basis of simple interatomic interactions cannot reproduce the elastic anisotropy of crystal with the C40 structure. The disagreement is considered to be a consequence of the occurrence of internal displacements during elastic deformation in crystals with the non-centrosymmetry.
  Intermetallics 6:607-611. · 1.65 Impact Factor
• Article: Photoinduced anisotropy in chalcogenide glasses in a wide spectral range studied by reflectance difference spectroscopy

  V Lyubin, T Yasuda, A.V Kolobov, K Tanaka, M Klebanov, L Boehm
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  ABSTRACT: We present the results of an investigation of photoinduced anisotropy in films and bulk samples of chalcogenide glasses As50Se50 and Ge20As20S60 using reflectance difference spectroscopy. Anisotropy in a wide spectral range (1.5–5.5 eV) can be generated and reorientated many times by linearly polarized light. We conclude that possibility of orientation and reorientation with the linearly polarized light not only of defects and scattering centers but also of the interatomic covalent bonds is characteristic for different chalcogenide glasses. We have found that doping of a chalcogenide glass Ge20As20S60 by rare earths does not change the parameters and characteristics of photoinduced anisotropy.
  Physica B Condensed Matter 245(3):201-205. · 1.06 Impact Factor
• Article: Thermal characterization of a polyethyleneglycol (PEG)-derivative induced vesicle fusion as revealed by high sensitivity differential scanning calorimetry

  M. Kodama, S. Tsuchiya, K. Nakayama, Y. Takaichi, M. Sakiyama, K. Akiyoshi, K. Tanaka, J. Sunamoto
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  ABSTRACT: Fusion phenomenon of a sonicated large vesicle induced by a derivative of polyethyleneglycol (PEG) was thermodynamically investigated by high sensitivity heating and cooling differential scanning calorimetry (DSC). These studies indicated that the PEG-derivative penetrates into the hydrophobic region of phosphatidylcholine bilayer membrane and leads to a loosely packed structure of the membrane in the liquid crystal state in preference to the gel state. The vesicle incorporating the PEG-derivative induced a fusion with the pure large vesicle, giving rise to an increase in the vesicle size and a decrease in the phase transition enthalpy of the gel-liquid crystal. Based on the calorimetric data, the fusion process was discussed from the viewpoint of the energetics of the PEG-derivative - lipid and the lipid - lipid interactions operating in the lipid membrane of fused vesicles.
  Thermochimica Acta 163:81-88. · 1.80 Impact Factor
• Article: Deoxycytidine uptake by isolated membrain vesicles from Escherichia coli K 12

  Y. Komatsu, K. Tanaka
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  ABSTRACT: 1.1. Two different deoxycytidine-uptake systems were found in isolated membrane vesicles of Escherichia coli K 12 cells: one was not significantly inhibited by guanine nucleosides, the other was markedly inhibited by these nucleosides.In isolated membrane vesicles of a showdomycin-resistant mutant (Shmr-001), the former system was no longer detectable but the latter was found to remain active.2.2. The deoxycytidine uptake by these systems was stimulated by reduced phenazine methosulfate, d(-)-lactate, succinate, and NADH, but not by ATP, phosphoenolpyruvate, or phosphoribosyl pyrophosphate.The reduced phenazine methosulfate-stimulated uptake of deoxycytidine by these systems was markedly inhibited by sodium azide.3.3. Among sulfhydryl reagents tested, N-ethylmaleimide did not significantly inhibit the uptake of deoxycytidine by these systems, even at very high concentrations; p-chloromercuribenzoic acid did inhibit uptake.4.4. The antibiotic showdomycin strongly inhibited the uptake of deoxycytidine by membrane vesicles of Escherichia coli K 12 but only slightly inhibited that by membrane vesicles of the mutant (Shmr-001). Further, showdomycin produced a rapid efflux of deoxycytidine from previously loaded membrane vesicles of Escherichia coli K 12.These results suggest that showdomycin is transported by the deoxycytidine transport system which is not inhibited by guanine nucleosides in isolated membrane vesicles of Escherichia coli K 12.
  Biochimica et Biophysica Acta (BBA) - Biomembranes. 311(4):496-506.
• Article: Remineralization of desalinated water by limestone dissolution filter

  V. Yamauchi, K. Tanaka, K. Hattori, M. Kondo, N. Ukawa
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  ABSTRACT: Remineralization by the limestone process is now widely used in the post-treatment sections of MSF desalination plants and RO plants.This paper discusses the optimization of the process design based on our experiments, process simulation and the data obtained from actual plant operation. The following aspects were considered. •- evaluation of limestone dissolution kinetics.•- design parameters of limestone filter bed, such as LHSV, particle size, CO2 concentration, etc.•- effect of backwashing•- CO2 availability from MSFE venting system.•- residual CO2 desorption before a alkali dosing, etc.Through this study, the residual CO2 desorption process by a simple air bubble column has been developed.With the application of this process, alkali consumption for pH adjustment is remarkably reduced and a high by-pass ratio of limestone filter (about 70%) can be realized. This process will contribute to reduce not only the variable cost, but the fixed cost of a remineralization plant.
  Desalination. 66:365-383.
• Article: Pore size distribution measurements of polymer hydrogel membranes for artificial kidneys using differential scanning calorimetry

  K. Ishikiriyama, A. Sakamoto, M. Todoki, T. Tayama, K. Tanaka, T. Kobayashi
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  ABSTRACT: The pore size distributions, PSDs, of hydrogel-hollow-fiber membranes such as poly(methyl methacrylate), cellulose triacetate, polyacrylonitrile and polysulfone utilized as artificial kidneys have been characterized using differential scanning calorimetry via thermal porosimetry, termed thermoporosimetry by the authors. The nitrogen gas adsorption-desorption technique was applied to the membranes after freeze-drying to determine the PSDs and, moreover, thermoporosimetry was applied to the membranes before freeze-drying and those refilled with water after freeze-drying, i.e. after nitrogen gas adsorption-desorption measurements. As a result, for the freeze-dried membranes, the PSDs determined using nitrogen gas desorption were found to be generally in good agreement with those obtained using thermoporosimetry. In addition, the PSDs of the poly(methyl methacrylate) membrane before and after freeze-drying were found to be quite different, although the PSDs of the cellulose triacetate, polyacrylonitrile and polysulfone membranes were nearly similar before and after freeze-drying.
  Thermochimica Acta 267:169-180. · 1.80 Impact Factor
• Article: Synthesis of electrically conductive organic thin film by plasma polymerization of 3,4,9,10-perylenetetracarboxylic dianhydride

  K. Tanaka, M. Murashima, T. Yamabe
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  ABSTRACT: The first synthesis of electrically conductive organic thin film by plasma polymerization (glow-discharge chemical vapour deposition) is reported. The monomer specifically employed is 3,4,9,10-perylenetracarboxylic dianhydride consisting of five-condensed aromatic rings attached by carboxylic groups outside the rings. The film is air-stable and hard enough not to be scratched out. Electrical conductivity of the samples measured is more than 1.0 × 100Scm-1 with n-type carriers at room temperature. Preliminary spectroscopic data are also to be shown.
  Solid State Communications 67(2):159-161. · 1.65 Impact Factor
• Article: Structure and properties of deeply n-doped polyacenic semiconductor (PAS)

  S. Yata, H. Kinoshita, M. Komori, N. Ando, T. Kashiwamura, T. Harada, K. Tanaka, T. Yamabe
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  ABSTRACT: Polyacenic semiconductor (PAS) films (H/C = 0.30) prepared from pyrolytic treatment of phenol-formaldehyde resin can be deeply doped with lithium up to 16.5% starting from IV versus Li/Li+ with good reversibility. From the 1st to the 100th doping-undoping cycle the X-ray diffraction pattern almost did not change. It has been found that PAS has excellent stability even at the deeply doped state. Moreover, the XPS spectra show that the doped lithium in PAS is in neither metallic nor ionic state.
  Synthetic Metals 55(1):388-393. · 1.83 Impact Factor
• Article: Metal–insulator transition in the one-dimensional organic conductor (TSM-TTP)(I3)5/3

  T Kawamoto, T Mori, Y Misaki, K Tanaka, H Mori, S Tanaka
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  ABSTRACT: (TSM-TTP)(I3)5/3 (TSM-TTP: 2,5-bis[4,5-bis(methylseleno)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) is a one-dimensional organic conductor which undergoes a metal–insulator transition at TMI≈20 K. High pressure resistivity, ESR, and static magnetic susceptibility measurements have been carried out to clarify the origin of the metal–insulator transition. The metal–insulator transition temperature is not completely suppressed even under a pressure of 11.8 kbar. The ESR line shape shows no anomaly and the magnetic susceptibility shows a slight increase below 70 K, and remains paramagnetic down to 1.75 K; no evidence of spin-Peierls or antiferromagnetic transition is obtained.
  Physica C Superconductivity 299:36-40. · 1.01 Impact Factor
• Article: Precision measurement of antiproton spectrum with BESS

  S. Orito, T. Maeno, H. Matsunaga, K. Abe, K. Anraku, Y. Asaoka, M. Fujikawa, M. Imori, M. Ishino, Y. Makida, [......], T. Sonoda, R. Streitmatter, J. Suzuki, K. Tanaka, I. Ueda, N. Yajima, T. Yamagami, A. Yamamoto, T. Yoshida, K. Yoshimura
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  ABSTRACT: The absolute fluxes of the cosmic-ray antiproton are measured at solar minimum in the energy range 0.2 to 3.2 GeV, based on 460 antiprotons unambiguously detected by BESS spectrometer during its '95 and '97 balloon flights from Lynn Lake, Canada. In the resultant antiproton spectrum we have detected a clear peak around 2 GeV and measured its flux to 10 % accuracy. The position and the absolute flux of the peak agree with the prediction of the Standard Leaky Box model for the “secondary” antiprotons. At low energies below 1 GeV, we observe an excess antiproton flux over the simple Standard Leaky Box prediction. This might indicate that the propagation mechanism needs to be modified, or might suggest a contribution of low-energy antiproton component from novel sources such as evaporating primordial black holes or the annihilating neutralino dark matter. Data from '98 and future flights are expected to help us to clarify the situation.
  Advances in Space Research 26(11):1847-1850. · 1.18 Impact Factor
• Article: Electron effective mass and nonparabolicity in InGaAs/InAlAs quantum wells lattice-matched to InP

  N. Kotera, H. Arimoto, N. Miura, K. Shibata, Y. Ueki, K. Tanaka, H. Nakamura, T. Mishima, K. Aiki, M. Washima
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  ABSTRACT: Nonparabolic electron effective masses in InGaAs quantum wells (QWs), sandwiched by thick InAlAs barriers of 0.52-eV band offset, were studied in normal and parallel directions to the QW plane. The Normal mass was experimentally obtained by observing interband photocurrent spectra of undoped InGaAs multi-QW structures. The mass increased by more than 50% from the bulk band edge mass, 0.041m0. Electron eigenenergies were calculated in QWs based on Kane's three-level band theory. The calculated ‘apparent’ normal mass as a function of kinetic energy up to 0.5 eV agreed well with experiments. The parallel mass in n-type modulation-doped InGaAs QWs was experimentally obtained by pulse cyclotron resonance up to 100 T. The analysis in quantizing magnetic fields, modified for two-dimensional QWs, fits well with cyclotron energy. The ‘apparent’ parallel mass as a function of energy was obtained consistently.
  Physica E Low-dimensional Systems and Nanostructures 11:219-223. · 1.53 Impact Factor
• Article: Fabrication and transport properties of MgB2 wire and coil

  K Tanaka, M Okada, H Kumakura, H Kitaguchi, K Togano
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  ABSTRACT: The paper reports the first successful fabrication and test of a MgB2 coil. We have fabricated 15 m long MgB2-superconducting wires by a powder-in-tube method using Ni-sheath without any heat treatments during the processing. The MgB2/Ni tape has a good uniformity of high Jc value (500–600 A/mm2 at 4.2 K and 0 T) along the tape length as well as a nice bending tolerance. Ic degradation of the tape occurred at the bending strain of as high as 1%. Using a 10 m long Ni-sheath tape, we have made a small solenoidal coil with 80 turns to be tested in liquid helium. The coil showed a typical training effect, Ic increasing by repeating the excitation, and the highest Ic value we obtained was 105 A, which generated the central field of 0.13 T.
  Physica C Superconductivity 382:203-206. · 1.01 Impact Factor