The accurate particle classification of separation size from 10 to 100μm is required in practical particle handling process. The cut size of louver type separator can be controlled from 10 to 50μm in size range. This report examines the improvement methods of particle separation performance in louver type separator by use of numerical simulation. The several new methods to improve separation performance are found based on simulation and experimental studies. The separation performance of new type louver separator is higher than that of the standard type. It is also found that the separation performance increases by use of flow rectifier section after the inlet flow. The adhesion probability of particle on inclined louver blades was measured experimentally. The adhesion probability indicated maximum value for particle diameter about 15μm. The results of numerical simulation, which includes flow rectifier section and particle adhesion probability, agreed with the experimental data.

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To activate the photocatalytic behavior of predominantly amorphous TiO₂ fine particles, the surfaces of the particles were modified by immersion in sulfuric acid aqueous solutions with different concentration, followed by heating at 525℃ for 1 h. The photocatalytic activity for acetaldehyde decomposition under UV irradiation increased on increasing the sulfuric acid concentration in the solutions used for immersion from 0.001 N to 1 N ; however, intermediate products, such as acetic acid, methanol and formic acid, were generated and remained in the case of immersion in 1 N sulfuric acid aqueous solution. The rate of decomposition of acetaldehyde remarkably increased, without generation of intermediate products, on using 0.001 N sulfuric acid for the immersion of amorphous TiO₂ fine particles. Since only immersion in a sulfuric acid aqueous solution did not activate the photocatalytic behavior of rutile TiO₂ particles, they were treated with a 3 mass％ aqueous solution of hydrogen peroxide, followed by immersion in a 1 N sulfuric acid solution and heat treatment. The rate of decomposition of acetaldehyde under UV irradiation using the surface treated rutile particles was increased about 10 times higher than that of the untreated rutile particles.

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Low temperature process below 100℃ under atmospheric pressure is a very useful technique to create inorganic nanocomposite thin films on various kinds of substrates, such as glass, ceramics, metal, alloy, and plastics. Nanocomposite material consisting of photocatalytic ceramic matrix and noble metal nanoparticles were prepared by both sol-gel process followed by hot-water treatment below 100℃ and photodeposition technique at room temperature under UV light irradiation. For example, nanocomposite thin film consisting of titania ceramic matrix and palladium metal nanoparticles works as an optically readable hydrogen gas sensor which can operate at room temperature. I believe that this low temperature synthesis can be applied to prepare functional materials or devices with well-controlled nanostructure.

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La_0.75SSr_0.25MnO₃ magnetic fine particles were synthesized by ultrasonic spray pyrolysis. The properties of the obtained particles （particle diameter, crystallite size and Curie temperature） could be controlled by the synthesis temperature. Furthermore, the particles generated heat in the AC magnetic field, and the particle temperature attained constant values near each Curie temperature quickly. These results showed that an application to heat media for hyperthermia therapy was expected.

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