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Volume 33, Issue 3
Displaying 1-10 of 10 articles from this issue
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Kikuo OKUYAMA1996 Volume 33 Issue 3 Pages 169
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
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Takao YAMAMOTO, Shigeki TSUKUI1996 Volume 33 Issue 3 Pages 170-175
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA superparamagnetic nanocomposite of silver and iron oxide was synthesized by inert gas condensation. The procedure involved: (1) coevaporation of silver and iron, (2) in-situ oxidation of iron particles, (3) in-situ compaction, and (4) post-annealing in an inert or an oxidizing atmosphere. The magnetization plots against H/T fell on a single curve from room temperature to 160K, providing evidence of superparamagnetism. Annealing treatment modifies the effective magnetic moment size and saturation value of magnetization. The iron oxide phase giving rise to the magnetism was investigated by Mössbauer and X-ray absorption spectroscopies. The magnetic species was identified as γ-Fe2O3 after the post annealing treatments, while Fe and Fe3O4 coexist in the as-prepared loose powder and the as-compacted pellet. The present process is a potential synthesis route for magnetic nanocomposites useful for applications.View full abstractDownload PDF (690K) -
Hiroshi FUDOUZI, Mikihiko KOBAYASHI, Mitsuru EGASHIRA, Norio SHINYA1996 Volume 33 Issue 3 Pages 176-181
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe creation of new advanced functional materials is anticipated by assembling micrometer-sized particles which have various kinds of functions. In this work, a new concept for assembling powder particles is proposed, and preliminary research results of this assembling are reported. The process for assembling is as follows; (1) electrified patterns are drawn on calcium titanate substrate using electron beam drawing and observed by the voltage contrast method, (2) the substrates are dipped into solvent in which spherical silica particles (5μm in diameter) are dispersed, and (3) the particles are adhered to the electrified patterns under suitable conditions. The amounts of adhered particles are influenced by the density of particles in the solvent, the dose electron density of electrification and dipping time of the substrate into the solvent. By using adequate values of these parameters, comparatively clear silica particle arrangements on the electrified patterns were obtained.View full abstractDownload PDF (6448K) -
Yoshikazu MIYAKE, Kazuo MIWA, Eiichi AMANO, Makoto UMESAWA, Yasushige ...1996 Volume 33 Issue 3 Pages 182-186
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn order to elucidate the mechanism of the CdS fine particles formation in microemulsions, the time courses of the spectra of CdS fine particles were measured both in the microemulsion and in the aqueous phase. The spectra of CdS fine particles in microemulsions depend on the water-pool size of the microemulsions. The rate of spectra change in microemulsions was much slower than that in the aqueous phase. At the initial stage of fine particle formation, the particle size changes reversibly. The behaviour cannot be interpreted by some models for the growth of the particles. It is inferred that the behaviours are caused by the surfactants in the microemulsions, but the role of surfactant in the formation cannot be proved.View full abstractDownload PDF (626K) -
Takafumi SETO, Kikuo OKUYAMA, Atsushi HIROTA1996 Volume 33 Issue 3 Pages 187-191
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSWhite colored, tetrapod-shaped and conductive fine particles are synthesized by doping alumimium into zinc oxide using the chemical vapor deposition (CVD) method. Particle morphology changes due to precursors, oxidants and vapor concentration are observed by transmission electron microscopy (TEM) and X-ray diffraction method (XRD). The electric resistivity of the particles is measured by the four-point probe method to examine the electric property of generated particles. Morphology and electric resistivity can be controlled by changing the aluminium vapor concentration and the tetrapod-shaped zinc oxide particles with a low resistivity of about 5Ωm obtained when aluminium acetate is used.View full abstractDownload PDF (1973K) -
Kikuo OKUYAMA, Norikazu TAGAMI, Shinkichi TAMAKI, Noboru TOHGE, I. Wul ...1996 Volume 33 Issue 3 Pages 192-198
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSIn the preparation of fine particles of metal sulfide, such as zinc sulfide and cadmium sulfide using the spray pyrolysis method, the electrostatic spray method was applied to atomize the starting solutions. The optimum operation conditions where the droplets can be generated from a Taylor cone were examined experimentally. It is shown that the use of the electrostatic spray pyrolysis method is available for preparing several dozen nanometer size fine particles, in comparison with a typical ultrasonic spray pyrolysis method that produces fine particles of several hundred nanometer size.View full abstractDownload PDF (3460K) -
Yasushige MORI, Yoshihisa MURAO, Yoshikazu MIYAKE1996 Volume 33 Issue 3 Pages 199-203
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe formation of colloidal gold produced from hydrogen tetrachloroaurate by three kinds of the reducing agents is studied by using a spectrophotometer. The absorption due to gold sol formation appeared in the 500 to 600nm wavelength. When tri-sodium citrate is used as a reducing agent, the wavelength of maximum absorbance due to colloidal gold shifts from high to low values and approaches to a constant value of 525nm. It apparently indicates that the particle size decreases over the course of the reaction. The reaction rate of the formation of gold sol decreases with the increase in the tri-sodium citrate concentration. Howerer, when citric acid or 1, 3-acetone dicarboxylic acid is used, the wavelength of maximum absorbance is almost constant at 525nm, and the reaction rate increases as a function of the reducing agent. The reason of the difference in these results could not be found in this work, so it might be necessary to study the citrate anion absorption of the surface of gold sol or the complex formation between citrate and gold ions.View full abstractDownload PDF (549K) -
Crystallization Processes for Particle ProductionMasakuni MATSUOKA1996 Volume 33 Issue 3 Pages 204-211
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
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[in Japanese]1996 Volume 33 Issue 3 Pages 212-228
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
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[in Japanese]1996 Volume 33 Issue 3 Pages 229-231
Published: March 10, 1996
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSDownload PDF (440K)
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