Earozoru Kenkyu
Online ISSN : 1881-543X
Print ISSN : 0912-2834
ISSN-L : 0912-2834
Volume 13 , Issue 4
Winter
Showing 1-3 articles out of 3 articles from the selected issue
Research Paper
  • Takafumi SETO, Nobuhiro AYA, Kikuo OKUYAMA, Takeshi HATA
    1998 Volume 13 Issue 4 Pages 337-342
    Published: December 20, 1998
    Released: January 07, 2010
    JOURNALS FREE ACCESS
    White colored and highly conductive (electric resistivity ∼10 Ωcm) fine particle of aluminum doped zinc oxide is generated by gas phase reaction of zinc vapor, aluminum acetate vapor and oxygen. The morphology and crystal structure of generated particles is measured by electron microscopies and x-ray diffraction. From experimental results, it is found that the chemical stoiochiometry of zinc, aluminum and oxygen, (Zn : Al : O), is important parameter to control both particle morphology (size, shape and color) and electric characteristic. It is also found that the resistivity of produced particles decrease with water vapor addition, since water vapor may assist decomposition of aluminum acetate.
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  • Norio ITO, Akira MIZOHATA
    1998 Volume 13 Issue 4 Pages 343-353
    Published: December 20, 1998
    Released: January 07, 2010
    JOURNALS FREE ACCESS
    In this paper we describe the results of a long-term observation on the particulate sulfate in the atmosphere over Sakai, Osaka, Japan. Since 1986 an atmospheric particulate sample has been collected daily on the quartz fiber filter in the urban area of Sakai. After extracting ultrasonically water soluble materials from the obtained sample into deionized distilled water, concentrations of sulfate and so on were determined by applying ion chromatography method. Monthly mean concentrations of non-sea salt (nss-) and sea salt (ss-) sulfate for a period of ten years from January 1986 to December 1995 were estimated from the observed concentrations. Using the least squares method, we determined the coefficient values of the linear function expressing concentration variation of nss-sulfate for the period of ten years. Although the rate is considerably different with the month, the concentration of nss-sulfate for each month has an increasing tendency. Consequently the concentration of nss-sulfate was increasing annually at the rate of 0.22 ± 0.05 μg/m3, and its annual mean varied from 3.5 to 5.7 μg/m3 for these ten years. It can be considered that this cause is the remarkably increasing emission of sulfur dioxide in China.
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  • Satoru CHATANI, Mikio KASAHARA, Kouhei YAMAMOTO, Susumu TOHNO
    1998 Volume 13 Issue 4 Pages 354-360
    Published: December 20, 1998
    Released: January 07, 2010
    JOURNALS FREE ACCESS
    To investigate the physical and chemical characteristics of atmospheric aerosols, three factors of size distribution, concentration and chemical composition are usually most important. Atmospheric aerosols were sampled by using a 12 stages Andersen sampler. Sampling was carried out once a month from July 1995 to June 1996. Sampled aerosols were separated into the soluble and insoluble components. The concentrations of 15 elements in both components were determined by a PIXE analysis. The mass size distribution of particulate matters (PM) was described by a bimodal distribution having one peak each in the fine and coarse fractions. The mass distribution of each element was illustrated in three types: mono-modal distribution having only one peak in the fine or coarse fraction and the bimodal distribution. The size distribution type of each element was estimated by the mass median diameter. The concentration ratio of the each element to PM in the coarse fraction was higher than that in the fine fraction. Solubility of all elements in the fine fraction was higher than that in the fine fraction. Enrichment factor of each element was calculated, and it is suggested that K, Ca, Ti, Mn, Fe in the coarse particles are originated from soil dusts.
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