Tungsten content in granitic rocks is precisely determined by an instrumental neutron activation analysis method (INAA) using several standard samples. Natural geostandard rocks are GSJ geostandard of JG-1, JG-1a, JG-2, JR-2 and JR-3, and artificial standard materials of JR-2 with added scheelite powder and tungsten-doped quartz sand were employed for the analysis. Each sample (100mg) was irradiated for short time (1min, 2min and 3min) at thermal neutron flux 2.8×10¹³n/cm²/s and for long time (60min) at thermal neutron flux 2.3×10¹³n/cm²/s. Gamma-ray spectrum of ¹⁸⁷W at 685.72keV was used for the tungsten analysis in geostandards. The ¹⁸⁷W gamma-ray spectrum was not recognized for Na-rich JG-1 (W concentration=1.5ppm), while the gamma spectrum of that was recognized for JR-2 (1.8ppm). S/N ratios of ¹⁸⁷W for geostandards that irradiated for 3min and after cooling for 6 day were higher than those of another irradiation conditions. The analytical error of tungsten in geostandards with the confidential limit of 95% was ± 4.7ppm. This INAA with 3min irradiation is the most suitable method for the tungsten-bearing samples was successfully applied to wide range of tungsten (i. e. low W concentration of non-mineralized granites to high W concentration of mineralized granite and scheelite-bearing ore).

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Electrical Sialon ceramics having some contents of TiN and SKS3 metal were joined with Ag-Cu-Ti active brazing metal layer having a thickness of 100μm or 400μm at a temperature of 1113K for 300s in a vacuum. The residual stresses on the brazed joint samples were measured in the ceramics side and the metal side by X-ray stress analysis. The linearity in 2θ-sin² φ diagram was confirmed for X-ray diffraction from the grinded surfaces of metal and ceramics. The residual stresses in the ceramics and metal sides of brazed joint samples indicated the characteristic distributions each other. The residual stress over several hundred MPa was measured within about 10mm from the joint interface in the metal side of brazed joint sample. The 400μm thickness of the brazing metal layer was especially effective to relax the residual stress of σ_y in the ceramics side (σ_y: residual stress in vertical direction to the joint interface). And when the brazing metal layer thickness was 400μm, the residual stress σ_y in the metal side showed almost zero value due to the plastic deformation of the brazing metal layer.

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Abstract Japanese cedar (Cryptomeria japonica D. Don) bark was pyrolyzed in a stream of N₂ at 473-673K for 3-12h under atmospheric pressure. The resultant carbonaceous residues were activated in a stream of CO₂ at 1173K for 1h. Adsorption of N₂ at 77K was measured to investigate the pore structure and the surface properties of the pyrolyzed and activated materials from the cedar bark. Both specific surface areas and total pore volumes of the materials pyrolyzed at temperatures below 573K were small, indicating that pore structures were not developed under mild conditions. However, those of the samples heated at 673K increased with increasing time of the treatment, during which micro porosity was mainly developed. Activation of the pyrolyzed cedar bark led to drastic increase in specific surface area and pore volume. The increase was due to the selective formation of the micro pores which distributed mainly less than 0.35nm in radius. Analytical results of adsorption data using t-plot and α_s-plot and IR spectra methods suggest that the surface properties of both pyrolyzed and activated cedar bark are different from those of typical carbon black. It is indicated that organic moiety and oxygenated functional groups originated from cedar bark may affect the surface characteristics of pyrolyzed and activated cedar bark.

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Japanese cedar (Cryptomeria japonica D. Don) bark was pyrolyzed in a stream of N₂ at 573-1273K for 3-12h under atmospheric pressure. Fibers of the cedar bark that mainly comprise cellulose, hemicellulose and lignin shrunk during heat treatment. However breaking down of the fibers was not observed during the pyrolysis, leading to the formation of fibrous carbon materials from cedar bark. The development of micro porosity was observed for the materials pyrolyzed at temperatures above 773K. The increase in specific surface area and total pore volume was due to the selective formation of micro pores which were distributed sharply around 0.32 to 0.4nm in radius. Analysis of adsorption data by t-plot and α_s-plot methods suggest that the properties of the surface of carbonaceous cedar bark pyrolyzed below 873K are quite different from those of typical carbon black, while those of cedar bark pyrolyzed at 1073-1273K are similar to that of carbon black. It is indicated that organic moiety and functional groups originated from cedar bark may affect the surface characteristics of pyrolyzed cedar bark under relatively mild conditions.

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The effect of surface orientation on dissolution behavior of type 310S stainless steel single crystal was investigated by potentiostatic etching in the active region in H₂SO₄ -NaCl solution. (100), (110) and (111) planes were prepared by cutting at the given angles of single crystal. The dissolution rate changed with etching potential and surface orientation. Residual planes for oriented pits were determined from these dissolution rate ratios. The residual planes changed in the sequence of {110} → {110} + {111} → {111} as the potential increased from the corrosion potential.
These results imply an important relationship between fracture surface in stress corrosion cracking and faceting dissolution of stainless steels.

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This research focuses on bioremediation method of oily contaminated soil. Three sets of bioremediation experiment were conducted using bioprocessing medicines and water with Pseudomonas mendocina. The best experimental condition for bioremediation of oily contaminated soil is well discussed. Oil concentration in the soil was measured using the gravimetric analysis method after extracting with normal hexane. Moreover, a qualitative analysis of the oily contaminated soil was investigated by means of mass spectroscopy method (GC-MS). The experimental results showed that an attack of bacteria on the oily contaminated soil caused a significant decrease of the TPH density less than 20% from its original value 5600ppm.

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In order to develop high strength new casting aluminum alloys, a relation between microstructure and strength in multiphase eutectic alloys was analyzed from points of view of both theoretical and experimental approaches. Initially, microstructure of multiphase eutectics was discussed.
Secondary, an Al-Ce-Ni multiphase eutectic alloy was cast and examined by compression test.
Finally, strengthening mechanism of the Al-Ce-Ni multiphase eutectic alloy was analyzed. The results obtained are as follows. Even in the conventional foundry technique the multiphase eutectic alloy has large amounts of aluminide particles being very fine because of the independently crystal nucleation. The Al-Ce-Ni multiphase eutectic alloy showed 30∼200% higher strength than commercial casting aluminum alloys. The strength consisted of strength of the aluminide particle itself, internal stress due to dislocations in Al phase and also Orowan stress increments due to the fine aluminide particles. This indicates the possibility in principal to develop new casting aluminum alloys.

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