Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 81 , Issue 2
Showing 1-17 articles out of 17 articles from the selected issue
  • Yujin TERASAWA, Yuki FUJIO, Chao-Nan XU
    2013 Volume 81 Issue 2 Pages 77-81
    Published: February 05, 2013
    Released: February 05, 2013
    In this study, we investigated an origin of low reproducibility of blue phosphor (CaMgSi2O6:Eu) by means of XRD, SEM, cathodoluminescence, photoluminescence, and thermoluminescence. There were no changes in the crystal structure, particle size, surface morphology, and cathodoluminscence property. On the other hand, it was seen that an increase in photoluminescence intensity induced a corresponding decrease in peak area of thermoluminescence spectrum, and the photoluminescence intensity was almost linearly proportional to the peak area of thermoluminescence spectrum. In addition, similar relationship was also found in another blue phosphor Sr3MgSi2O8:Eu. It is suggested that the low reproducibility of the photoluminescence intensity may be due to the change of the thermoluminescence spectra. Thus, by controlling the concentration of traps in the host crystal of the phosphor, it is possible to predict the potential performance of its photoluminescence.
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  • Jianying QU, Tongfang LOU, Shiping KANG, Xueping DU
    2013 Volume 81 Issue 2 Pages 82-85
    Published: February 05, 2013
    Released: February 05, 2013
    The electrochemical reaction of catechol (CC) and hydroquinone (HQ) was investigated at poly-(p-aminobenzoic acid) (p-ABA)/multiwall carbon nanotubes (MWCNTs) composite film modified glassy carbon (GC) electrode via cyclic voltammetry (CV). Separation of the peak potentials for CC and HQ was about 105 mV in 0.1 mol/L H2SO4, which makes it suitable for simultaneous determination of these compounds. Under optimized conditions, the oxidation current of CC and HQ have been enhanced linearly with the concentration in the range of 1 × 10−5–1 × 10−3 mol/L (r = 0.9979) and 1 × 10−5–1 × 10−3 mol/L (r = 0.9948), with the detection limit of CC and HQ 4 × 10−6 and 2.7 × 10−6 mol/L, respectively. The proposed method has been applied to determine CC and HQ simultaneously with good results, which shows excellent stability and reproducibility.
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  • Hirofumi SUMI, Toshiaki YAMAGUCHI, Koichi HAMAMOTO, Toshio SUZUKI, Yos ...
    2013 Volume 81 Issue 2 Pages 86-91
    Published: February 05, 2013
    Released: February 05, 2013
    The effect of operating temperature on durability was investigated for direct butane utilization using microtubular solid oxide fuel cells (SOFCs). At 710°C, the performance of the Ni-Gd doped ceria (Ni-GDC) anode deteriorated rapidly for less than 2 h in butane fuel with relatively low steam/carbon (S/C) ratio at 0.044 because of a large amount of carbon deposition by butane cracking. The carbon nanofiber grew up from catalysis in the Ni-GDC anode after direct butane utilization at 660°C for 15 h. The carbon deposition rate in wet butane was slower than that in dry butane below 660°C on the Ni-GDC composite, because the oxidation of deposited carbon was also promoted by catalysis in the presence of water. The electric power could be generated continuously for more than 24 h in butane at S/C = 0.044 and relatively low operating temperature at 610°C using the Ni-GDC anode. Decrease in the operating temperature realized high durability against carbon deposition for direct butane utilization of SOFCs using the Ni-GDC anode.
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