Transactions of the Materials Research Society of Japan
Online ISSN : 2188-1650
Print ISSN : 1382-3469
ISSN-L : 1382-3469
38 巻 , 1 号
選択された号の論文の33件中1~33を表示しています
Regular Papers
  • Akihiko Suzuki, Takaei Yamamoto, Hiroki Cho, Toshio Sakuma
    2013 年 38 巻 1 号 p. 1-5
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    The transformation behavior of shape memory alloys is simulated for complex loadings of stress, strain and temperature. Calculations are made by using the “Accommodation Model” which is a constitutive model for shape memory alloys considering the accommodation behavior of the transformation strain. Calculated results are given for the super elastic behavior, the shape memory effect, the structural behavior of a shape memory wire with a bias spring, etc. The effect of the plastic strain on the transformation strain is also investigated. Also, for the case of the multi-axial stress state, calculated results are presented for the transformation behavior in the axial and shear stress state. These results are compared with those obtained by the experiment where tube specimens of the Ti-Ni shape memory alloy are subjected to the axial and torsion loading.
  • Kosuke Suzuki, Akio Hikasa, Nobuyuki Suzuki
    2013 年 38 巻 1 号 p. 7-10
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    To improve the surface performance, Nylon12/Polyamide-imide (PAI) composites were coated on aluminum substrates using a printing technique. Dimples were formed on the surface of the coating with sizes corresponding to the grain diameters of the nylon particles. The objective of this study was to investigate the influence of the dimples on the tribological behavior under oil lubrication. The effect of the sliding speed on the friction coefficient was also evaluated. Friction tests were performed using a ball-on-disk tribometer. The results revealed that the incorporation of dimples significantly improves the tribological properties. Particularly, the friction coefficients of the Nylon12/PAI composite coatings were much lower than that of the PAI-only coating at slow sliding speeds. The dimples played an important role in maintaining the oils under mixed lubrication. The friction coefficients of the Nylon12/PAI composite coatings initially decreased with an increase in the additive amount of nylon particles. However, the friction coefficients gradually increased when the volume fractions of Nylon12 exceeded about 3 to 5 vol. %. Based on tribological behavior, it was found that an optimum amount of nylon particles exists for PAI coatings.
  • Masaaki ISAI, Ikuta NAKAMURA, Takanori SATO, Yoichi HOSHI
    2013 年 38 巻 1 号 p. 11-15
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    TiO2 films were prepared with RF magnetron sputtering method. The platinum (Pt) films were deposited on the TiO2 films. They act as cocatalysts which improve organic-decomposition properties, but deteriorate hydrophilicity because they have hydrophobic property. It seems that the thickness of Pt films is one of the most important parameters to improve the organic-decomposition properties. It was found that an optimum thickness of Pt films is from 500 to 700Å to improve organic-decomposition properties without deteriorating hydrophilicity.
  • S. Tada, Y. Isoda, H. Udono, H. Fujiu, S. Kumagai, Y. Shinohara
    2013 年 38 巻 1 号 p. 17-20
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      We have investigated the thermoelectric properties of Na-doped Mg2Si0.25Sn0.75 solid solutions prepared by liquid-solid reaction and hot-pressing methods. Na doping was carried out by mixing sodium acetate (CH3COONa) into the starting materials Mg (nominal purity: 99.9 %), Sn (99.999 %) granules, and Si powder (99.9999 %). The Na-doped samples had p-type conductivity with positive signs of Seebeck and Hall coefficients. Furthermore, hole concentrations increased rapidly with an increase in the amount of Na doping. These results revealed that the Na atoms acted as acceptors in Mg2Si0.25Sn0.75. The Seebeck coefficient of Na-doped samples showed positive values between 300 and 750 K. A maximum power factor of 0.88 × 10-3 WmK-2 was observed for the Mg2Na0.020Si0.25Sn0.75 sample at 500 K. The dimensionless figure of merit ZT reached 0.17 at 450 K for all Na-doped samples.
Review Paper
  • Yoshimi Watanabe, Yasumasa Oya, Hisashi Sato
    2013 年 38 巻 1 号 p. 21-26
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Recently, centrifugal casting methods by using machining chips have been proposed. Machining chips of metal A are inserted into a spinning mold. Subsequently, the molten metal A is poured into the spinning mold. As a result, the molten metal penetrates into the space between the machining chips. At the same time, the machining chips are partially melted by the heat from molten metal. After the solidification, a ring or pipe shaped cast can be obtained. This may be an eco-centrifugal casting method, since the reduction of necessary power for casting will be expected. In this article, experimental results using Al and brass systems are reviewed.
Regular Papers
  • Hiroyuki Kitagawa, Kazuhei Yoshida, Yasuji Yamada, Shugo Kubo
    2013 年 38 巻 1 号 p. 27-29
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Aluminum-doped Zinc oxide (AZO) sputtering targets (10 mm in diameter and 5 mm thick) were prepared by a pulse-current sintering method, where metallic Al was selected as the Al source. The ZnO sintered materials doped using metallic Al showed low electrical resistivity owing to both the Al doping and precipitation of metallic zinc. AZO thin films were prepared by RF magnetron sputtering using the prepared target, and showed an electrical resistivity of approximately 9.6 × 10-4 Ωcm. Moreover, increase in electrical resistivity at the erosion area was small compared with that in films prepared with a conventional target.
  • H. Ito, A. Yamamoto, T. Suzuki, H. Saitoh
    2013 年 38 巻 1 号 p. 31-34
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    A novel method was presented to analyze the contribution of CN radicals to the N source of hydrogenated amorphous carbon nitride films based on the ratio of the fluxes, s=Φa-CN/ΦCN, where Φa-CN is the flux of N atoms deposited and ΦCN is that of CN radicals. Films were formed by the microwave discharge of C6H6 vapor diluted with N2. ΦCN was evaluated from the density of CN radicals determined from the intensity analysis of the laser-induced fluorescence spectra of the CN(A2Пi-X2Σ+) transition and the flow speed by a time-resolved emission measurement. Φa-CN was evaluated from the mass of a deposited film calibrated against the atomic compositions determined from the combination of Rutherford backscattering and elastic recoil detection measurements. From the comparison of the present s values and the sticking probability of CN radicals determined in our previous study [Spectrochimica Acta PartA: Molecular and Biomolecular Spectroscopy, 86, 256-265 (2012)], CN radicals were found to be the origin of 30-50% of N atoms of films fabricated in the present reaction system.
  • Shinichi Koguchi
    2013 年 38 巻 1 号 p. 35-36
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      An ionic-liquid (IL)-supported 18-crown-6 ether was prepared for performing acetylations and fluorinations. In this study the synthetic utility of the IL-supported 18-crown-6 ether catalyst, which is a recoverable and recyclable reagent is described.
  • Tzu-I Tsai, Horng-Chih Lin, Ting-Yao Lin, Kun-Ming Chen, Tien-Sheng Ch ...
    2013 年 38 巻 1 号 p. 37-40
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    This work employs double patterning and Ni salicides processes in the fabrication of polycrystalline silicon (poly-Si) thin-film transistors (TFTs) and studies the radio frequency (RF) performance of the fabricated devices. The fabricated TFTs show a high on-to-off current ratio (Ion/Ioff) of 1.78 × 107 and a high current drive of around 200 μA/μm. The cutoff frequency, ƒt, and maximum frequency of oscillation, ƒmax exceeds 8 and 11 GHz, respectively, biased at a low-operating drain voltage of 2 V. The equivalent-circuit models are also derived and characterized with both the measured and simulated S-parameters. These results demonstrate that the poly-Si TFT technique is promising for RF module implemented in the system-on-panel applications.
  • Ichiro Fujii, Tatsuya Kita, Kouichi Nakashima, Takahiro Takei, Nobuhir ...
    2013 年 38 巻 1 号 p. 41-44
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    BaTiO3 (BT) ceramics were prepared by electrophoretic deposition (EPD) or slip casting (SC) in a high magnetic field (HM) of 12 T using single-domain or multi-domain BT particles. The {110}-oriented BT ceramics with a Lotgering factor of 25% were prepared by HM-EPD of the single-domain BT particles, while no texture was observed for the BT ceramics prepared by HM-SC of the single-domain BT particles and for the BT ceramics prepared using the multi-domain BT particles regardless of the preparation methods. These results were discussed with factors that reduced the magnetic anisotropy of the BT particles.
  • Kouichi Nakashima, Ichiro Fujii, Satoshi Wada
    2013 年 38 巻 1 号 p. 45-48
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Low-temperature synthesis of barium zirconate (BaZrO3) was carried out using the composite-hydroxide-mediated (CHM) approach. The CHM method is based on chemical reaction of materials in the eutectic hydroxide melt. In this system, the eutectic point is at an NaOH:KOH molar ratio of 51.5:48.5 and a temperature of 165°C. The raw materials used to prepare BaZrO3 were zirconium dioxide and barium hydroxide. In this study, the morphology of the obtained BaZrO3 powder was investigated. X-ray diffraction measurements confirmed the formation of BaZrO3 with a perovskite structure. Scanning electron microscopy and transmission electron microscopy observations indicated that BaZrO3 nanocrystals were formed.
  • Ichiro Fujii, Atsushi Shimamura, Kouichi Nakashima, Nobuhiro Kumada, H ...
    2013 年 38 巻 1 号 p. 49-52
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Non-integer A and B site cation valence perovskite oxides with bismuth and niobium cations were synthesized. Using the tolerance factor, some single phase perovskite oxides were obtained. For the A1+xB5-xO3 type (Bix/2K-x/2+1)(TixNb1-x)O3 ceramics, the Curie temperature increased from approximately 200 to 350 °C with increasing x from 0.5 to 0.9. These results were discussed with the Abrahams relations.
  • Miyabi Kobayashi, Nobuhiro Kumada, Akira Miura, Takahiro Takei, Ichiro ...
    2013 年 38 巻 1 号 p. 53-55
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Fine particles of BiFeO3 were prepared from bismuth nitrate and iron nitrate in KOH solution by hydrothermal reaction. A single phase of BiFeO3 was prepared under hydrothermal condition of K/Bi ≥ 120 and above 180 °C. The TG curves of single phase of BiFeO3 indicated that the products included a small amount of OH group or water in spite of no detection of potassium atom by EDX. The particle size of BiFeO3 was ~ 10 μm and 10 ~ 20 μm for the products at 180 and 220 °C, respectively. The particle prepared at 220 °C was formed by aggregation of ~ 10 nm size particles with a cubic shape. From the pH dependence of ζ-potential the isoelectric point was about three.
  • Ichiro Fujii, Kenta Yamashita, Kouichi Nakashima, Nobuhiro Kumada, Eis ...
    2013 年 38 巻 1 号 p. 57-60
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    KNbO3 (KN) / BaTiO3 (BT) composites with heteroepitaxial interfaces were solvothermally synthesized using the barium titanate powder with a wide particle size distribution. Compared with the composites prepared with a narrow particle size distributions, the relative density increased to 68 - 80 %. The dielectric constant was increased to 300 - 450, while an obvious increase in the electric-field-induced strain was not observed. The dielectric and piezoelectric properties were maximized at the KNbO3 / BaTiO3 molar ratio of 0.5.
  • Wahyudiono, Siti Machmudah, Koichi Nagafuchi, Mitsuru Sasaki, Hidenor ...
    2013 年 38 巻 1 号 p. 61-67
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Pulsed discharge plasma is typical oxidation technologies for disposing organic compounds in aqueous solutions. In this paper, electric field generated by pulsed high-voltage discharge plasma over water surface has been performed under argon atmosphere to degrade dye compounds. The effects of various parameters with pulsed high-voltage arc discharge plasma are studied for decoloration of Orange G, Orange II, Congo Red, Naphthol Blue Black. The experiments were conducted at 313 K and 0.2 MPa using a batch type reactor. Intermediate compounds from the degradation of dyes in the aqueous products were analyzed by UV-Vis (ultra violet -visible) spectrophotometer. The dyes degradation increases with increasing peak pulse voltage applied which leads to the formation of its derived compounds. The decoloration rate significantly increased also with the number of pulse discharge plasma. When the number of discharge plasma was 20000x with 9 kV peak pulse voltage applied, the degradation of Orange G, Orange II, Congo Red, and Naphthol Blue Black could approach to 50.81 wt%, 41.64 wt%, 56.41 wt%, and 53.25 wt%, respectively.
  • Hiroharu Kawasaki, Daichi Taniyama, Tamiko Ohshima, Takeshi Ihara, Yos ...
    2013 年 38 巻 1 号 p. 69-72
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      Titanium oxide thin films were prepared by a pulsed laser deposition method using a Ti powder material target. Atomic force microscopy images of the films appeared to be nearly same as those of films prepared using a Ti bulk target. X-ray diffraction and X-ray photoelectron spectroscopy measurements suggested that polycrystalline titanium dioxide (TiO2) thin films can be prepared using a Ti powder target, and that their properties depend on substrate temperature and the argon and oxygen gas mixture. These results suggest that titanium oxide thin films can be prepared using a Ti powder target and their quality was almost the same as those of compared with the films prepared using a Ti bulk target.
  • E. Meng, K. Nakane, T. Matsushita, W. Li, S. Oda, K. Shirai, S.M. Cai, ...
    2013 年 38 巻 1 号 p. 73-79
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Various kinds of Ag nanostructures were grown on various metallic substrates using hexakisphosphate (IP6) as a silver carrier agent. The Ag nanostructures with three-dimensional dendritic structure, the two-dimensional dendritic structure, the two-dimensional fractal structure, particles and nanowire structures were controllably obtained. The morphological control by IP6 using additional metallic materials is proposed. The structural properties of the Ag nanostructures were examined, and the growth evolution of the nanostructures was discussed. It is considered that the IP6 plays an important role as a silver carrier agent for the structural and morphological control of the Ag nanostructures.
  • S. Kato, T. Yamaki, S. Yamamoto, T. Hakoda, K. Kawaguchi, T. Kobayashi ...
    2013 年 38 巻 1 号 p. 81-84
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Nanoparticles were formed by 100-keV tungsten-ion implantation in unpolished glassy carbon substrates at different fluences. The implanted samples were analyzed by Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, hydrodynamic voltammetry using a rotating disk electrode, and field emission scanning electron microscopy. A significant sputtering effect changed the depth profile during the course of irradiation and limited the amount of tungsten that could be retained on the substrate, which saturated at a fluence of around 6 × 1016 ions/cm2. The observed depth-profile change and saturation can be explained quantitatively by the calculated sputtering yield. The nanoparticles of tungsten carbides with diameters of around 16 nm were dispersed uniformly on the surface.
  • Ikeyama Masami, Sonoda Tsutomu
    2013 年 38 巻 1 号 p. 85-88
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    In order to improve poor corrosion protection property of Mg-alloy, we have been studied about Si incorporated DLC (Si-DLC) coatings with our bi-polar PBII (Plasma Based Ion Implantation) system. Recently, we have introduced new pulse power supply and studied the effects of the repetition frequency (R.F.) up to 20 kHz on the deposition rate of Si-DLC coatings and corrosion protection ability of the Si-DLC coatings on AZ31 (Mg-3%Al-1%Zn) alloy. On deposition rate, the deposition rate increases with the increase of the repetition frequency and gas pressure of precursor gas, generally. Delay time of -pulse application after +pulse application, pulse width and the peak pulse voltage of -pulse are also affected to the deposition rate. On corrosion protection ability, the coating made at 8 kHz of R.F. for 120 min with 1000 nm in thickness, the thickest coating is the best. Unfortunately, the higher deposition rate of higher R.F. can not make better corrosion protection property. Si-DLC coatings of several hundred nm in thickness are relatively transparent, which was confirmed by an optical measurement.
  • S. Hamamoto, K. Yamaguchi, K. Hojou
    2013 年 38 巻 1 号 p. 89-92
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      Sputter etching (SE) of Si substrate is employed to fabricate highly-oriented β-FeSi2 film on Si by means of ion beam sputter deposition (IBSD). In the present study, dependence on the irradiated fluence at the incident SE energies of 1 and 3 keV and at the deposition temperatures of 923 and 973 K, was investigated to discuss whether it is possible to obtain highly-oriented β-FeSi2 thin film with less radiation damage. At 973 K, irradiation of 3 keV Ne+ to an ion fluence of 3.7×1016 Ne/cm2 was needed to avoid the formation of α-FeSi2 phase and to obtain highly-oriented β-FeSi2 (100) film on Si (100) substrate. Whereas at 923 K highly-oriented β-FeSi2 (100) film was obtained with SE condition of 3 keV and 3.7×1015 Ne/cm2, which is merely 1/10 of the fluence required at 973 K. This means that the β-FeSi2 film can be fabricated with much less radiation damage so that presence of defects is considered to be much reduced.
  • Hiromichi Ryuto, Yuki Ohmura, Mitsuaki Takeuchi, Gikan H. Takaoka
    2013 年 38 巻 1 号 p. 93-96
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    The effects of irradiating ethanol cluster ion beams on mica surfaces were investigated. Traces were formed by the irradiation of ethanol cluster ion beams. The number of traces on the irradiated mica surface increased with the dose and acceleration voltage. On the other hand, the number of traces decreased with increasing retarding voltage. The contact angle of the mica surface irradiated with ethanol cluster ion beams increased with the acceleration voltage. The decrease in the numbers of potassium atoms on the mica surface and the increase in the surface roughness induced by the irradiation of ethanol cluster ion beams may be the causes of the increased contact angle.
  • Wolfgang Ensinger, Stefan Flege, Ruriko Hatada, Sevda Ayata, Takaomi M ...
    2013 年 38 巻 1 号 p. 97-100
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Since ion-beam-based methods for materials' modification are line-of-sight techniques, it is difficult to coat three-dimensional objects completely. Here, a device is described for coating rings by ion beam sputter deposition. A broad-beam ion source is combined with a sputter target consisting of two cones, forming the shape of the letter W in cross-section. With this technique, steel rings were coated with thin aluminium and chromium films. Adhesion measurements at different ring positions showed that the coatings were well adhering. Electrochemical corrosion tests proved that the coating was able to protect the steel ring from aqueous corrosion.
  • Akane Kitamura, Takahiro Satoh, Masashi Koka, Tomihiro Kamiya, Tomohir ...
    2013 年 38 巻 1 号 p. 101-104
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) are well known as Teflon®. Synchrotron radiation and focused ion beam irradiation are effective techniques for fabricating microstructures on the surfaces of Teflon. In this study, we created micro-patterns between micro-protrusions on FEP surfaces by using a combination of 3 MeV proton beam writing (PBW) and subsequent 250 keV nitrogen ion beam irradiation. First, we found that the proton microbeam made bubbles inside FEP samples. After their samples were irradiated with the nitrogen ion beam, dense micro-protrusions were formed on the surfaces other than the upper parts above the bubbles. Instead, the parts became smooth or depressed along the patterns of PBW. Thus, a microfabrication of Teflon was demonstrated by using two different ion beam irradiation.
  • Nunung Nuryanthi, Tetsuya Yamaki, Hiroshi Koshikawa, Masaharu Asano, S ...
    2013 年 38 巻 1 号 p. 105-108
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    A poly(vinylidene fluoride) film irradiated with 450 MeV 129Xe ions was etched in an aqueous potassium hydroxide solution at 80°C in a conductometric cell. The etching characteristics were investigated in situ at different applied voltages. The conductometric curves reached a plateau when the etching time was sufficiently long (up to 48 h); this plateau indicates that etching was complete in the damaged track and that the bulk etch rate was negligibly low. The applied voltage produced larger pores than the etching with no voltage. Higher voltages shortened the etching time; the voltage accelerated the etching before the pore breakthrough and during the pore growth. The increase in the etch rate was probably caused by the dissolved etching products being pulled away from the pores more efficiently at higher applied voltages. However, the effective pore diameter, deff, at the end of the etching was not substantially affected by varying the applied voltage. The final deff values calculated from the conductometric measurements were not consistent with the results acquired by scanning electron microscopy observations. This can likely be explained by inhomogeneous etching at the edge of the membrane.
  • Yasuhiro Yoneda, Shinji Kohara, Masayoshi Ito, Hiroshi Abe, Mitsuaki T ...
    2013 年 38 巻 1 号 p. 109-112
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    We performed local structure analysis of SmFe2 and TbFe2 in the crystallization process from amorphous by using synchrotron X-ray pair-distribution function (PDF) method. The giant mangetostrictive materials of these compounds can be controlled its property by ion irradiation. In amorphous TbFe2 and SmFe2, the mosaic block size was small and the short-range order structure owing to Fe-Fe network maintained. In crystalline SmFe2, a rigid long-range order structure of Fe-Fe and Sm-Sm network coexisted and it had a large mosaic block size. On the other hand, in crystalline TbFe2, Fe-Fe network degraded by Tb-Tb network owing to its lattice tolerance. The difference of the local structure is a cause of the difference in the Ar-ion irradiation effect.
  • Shigeki Matsunaga
    2013 年 38 巻 1 号 p. 113-117
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    The partial dynamic structure factors Sξη(k,ω) in molten RbAg4I5 have been obtained by molecular dynamics simulation (MD) using the pair potentials including the effect of polarizability of ions. From the obtained Sξη(k,ω), the longitudinal acoustic (LA), the longitudinal optical (LO), and the transverse acoustic (TA) modes have been observed. It is noteworthy that they are propagated mainly by the ions of different kind; LA and LO modes by I ions, TA modes by Ag ions. The relaxation of phonon is also discussed by Sξη(k,ω) using the model based on the hydrodynamics and the plasma frequency. As a conclusion, the origin of the TA phonon modes is attributed to the cation-cation interaction.
  • Toshimasa Suzuka, Mika Adachi, Zhong-Sheng Yang, Kazuhito Ogihara, Mat ...
    2013 年 38 巻 1 号 p. 119-122
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      In this study, a polymer-supported terpyridine–palladium complex was prepared and found to promote the Suzuki–Miyaura cross-coupling reaction in water. The terpyridine ligand was prepared from 4-methoxycarbonylbenzaldehyde, 2-acetylpyridine according to the reported procedures. The terpyridine ligand was immobilized onto a PS-PEG resin, and the complexation of the PS-PEG terpyridine ligand with Pd(II) gave the PS-PEG terpyridine–Pd(II) complex. The polymeric catalyst showed high catalytic activity and high reusability for this cross-coupling reaction. This catalyst was also applied to the synthesis of 2,6-disubstituted pyrimidines in water.
  • Jun Kawakami, Hiroko Kawaguchi, Kenta Kikuchi, Asako Yamaya, Shunji It ...
    2013 年 38 巻 1 号 p. 123-125
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Tryptanthrin derivatives, which are known antimicrobial agents, were synthesized, and their absorption and fluorescence spectral behaviors were investigated. Our results showed that 2-aminotryptanthrin exhibits both a high fluorescence quantum yield and large positive fluorescent solvatochromism.
  • D. Pathinettam Padiyan, S. T. Nishanthi
    2013 年 38 巻 1 号 p. 127-130
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
      Titania nanotubes are prepared by two-step electrochemical anodization of titanium foil and the influence of annealing (1, 2, 3, 4 & 5 h) is reported. Increase in crystalline nature with increase in annealing time is observed in X-ray diffraction (XRD) studies. The effect of annealing on morphology of the nanotubes is clearly seen in High Resolution Scanning Electron Microscope (HR-SEM) analysis. The diffuse reflectance spectra (DRS) studies reveal that the increase of annealing time brings the titania nanotubes optical absorption from UV to visible region. The 4 h annealed sample shows the higher photoconversion efficiency of 18.93 %. This enhancement is attributed to the improved crystallinity, anatase phase with lesser band gap.
  • Taishi Nakano, Minoru Fujii, Kenji Imakita, Shinji Hayashi, Takaaki Ts ...
    2013 年 38 巻 1 号 p. 131-134
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Enhancement of upconversion luminescence by small assemblies of Au nanorods such as dimers, trimers, tetramers, etc, is studied by comparing upconversion images with electron microscope images. We show that small assemblies starting from dimers can enhance the upconversion luminescence, while isolated Au nanorods cannot. The analysis of the data reveals that the gaps between nanorods act as hot spots for the enhancement of upcnversion luminescence.
  • S.-I. YAMAMOTO, Y. URAOKA, N. TAGUCHI, T. NONAKA
    2013 年 38 巻 1 号 p. 135-140
    発行日: 2013/03/01
    公開日: 2013/12/07
    ジャーナル フリー
    Distributed inorganic electroluminescence (EL) devices comprise a metal electrode, and can be fabricated at a low cost using coating processes. In this study, we deposited comb electrodes with narrow gaps between the teeth on a glass substrate, thus realizing a high electric field intensity that cannot be achieved with conventional structures. Au electrodes are deposited to form a comb shape and then spin-coated with a phosphor layer obtained by mixing ZnS phosphor particles with resins at a certain ratio. An AC voltage was applied to the gaps between the teeth of the comb electrode to emit light, from which the luminance was measured for different electric field intensities. The luminances measured from the glass substrate side (the bottom of the device) were low for a device with a Au comb electrodes (Au electrodes) when the electric field intensity was 15 V/μm. However, the luminances measured from the phosphor layer side (the top of the device) for the device with the Au electrodes were high. In contrast, the luminance measured from the phosphor layer side for the device with the Au electrodes 1.5-fold higher than that measured from the glass substrate side. This was because the luminance was not affected by the transmittance of the electrodes themselves when measured from the phosphor layer side. Therefore, it may be possible to produce a display that does not require transparent electrodes by using the phosphor layer side of a device with comb electrodes made of metals, such as Au, for the front side of the display.
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