Information flows among academic disciplines in Japan

An attempt is made to clarify the relationships among disciplines by examining the flow of citation and the migration of scholars in the humanities and social sciences in Japan. The results of both methods are consistent with each other. In humanities and social sciences in Japan, distinct hierarchical relationships are recognized between disciplines offering much information to other disciplines and disciplines obtaining much information from other disciplines.     

Colloidal Processing and Mechanical Properties of Whisker-Reinforced Mullite Matrix Composites

Aqueous colloidal suspensions in the two systems of CVD-processed ultrafine mullite powder (<0.1 μm), -Si₃N₄ whisker and -mullite whisker, were prepared near the isoelectric point of mullite (pH 7.0) to prevent cracking during drying of wet green compacts consolidated by filtration. The freeze-dried porous green compacts were hot-pressed with a carbon die at 1500°C for 1 h at a pressure of 39 MPa in N₂ atmosphere. The relative densities of the mullite matrix composites with whiskers of 0 to 10 vol% were in the range of 95.2% to 99.8%. Increasing the fraction of Si₃N₄ whisker increased the density, flexural strength, and fracture toughness of the hot-pressed composites. On the other hand, addition of the mullite whisker increased the fracture toughness but decreased the density and strength of the composites.     

Novel Route to Propylene Carbonate: Selective Synthesis from Propylene Glycol and Carbon Dioxide

High surface area zirconium phosphate in an amorphous phase exhibits high activities for water-related reactions such as hydrolysis of ethyl acetate and esterification of acetic acid with ethanol. The zirconium phosphate is insoluble during the reaction, is recoverable by simple filtration, and can be reused at least five times without any treatment.     

Mechanochemical Effects on the Formation and Properties of Various Nickel Phosphates

Mixtures of ammonium dihydrogen phosphate and basic nickel carbonate with P/Ni molar ratios of 2/3, 1/1, and 2/1 were ground in a planetary mill. The thermal behavior of the milled samples was investigated by differential thermal analysis, x-ray diffraction, and Fourier transform infrared spectroscopy. In addition, the samples were characterized by ultraviolet-visible reflectance spectroscopy, particle size distribution, scanning electron microscopy, and nitrogen adsorption measurements. As a result of mechanochemical effects, the targeted nickel phosphates were formed at lower temperatures, had a more vivid color, and consisted of more regularly shaped particles.