Effects of high energy (MeV) nitrogen ion-implantation in surface layer of steel were investigated. The steel samples were ion-implanted with nitrogen ions accelerating to energies of 1.5, 3.0 and 4.5 MeV at a dose of 8×1017 ion/cm2by a tandetron accelerator system. The depth profiles of nitrogen implanted samples were analyzed by secondary ion mass spectroscopy (SIMS) . The nitrides formed by MeV ion implantation of nitrogen were studied using X-ray photoelectron spectroscopy (XPS) .The hardness and the wear resistance of implanted steels were measured by the Vickers hardness testing and the ball-on-disk wear testing. The profiles show that carbon layers were formed on surfaces of implanted samples and nitride layers were formed under near surface. The hardness for each load in the implanted samples were affected by the ion energy. The wear resistance was improved by the nitrogen ion implantation.
Information is limited concerning variation of the δ15N with growth in marine organisms and consequently the effect of growth of marine biota on the δ15N is not yet well understood. The δ15N in 26 species of marine fishes taken from Japanese coastal waters together with 4664 stomach contents of these fishes were examined to investigate the effects of food habits and growth on the δ15N. The mean δ15N for two species that fed mainly on large-size fishes and six species that fed mainly on small-size fishes were 14.5±1.0‰ and 12.8±0.7‰, respectively. For five species that fed mainly on decapod crustaceans, two species that fed mainly on zooplankton, and three species that fed mainly on benthos (mainly Polychaeta), the δ15N were 13.0±0.7, 9.7±0.9, and 12.2±1.2‰, respectively. The mean δ15N in the species whose prey were mainly fish or decapod crustaceans was about 3-5‰ higher than the species whose prey was mainly zooplankton. Within the four species that shift their food habits with growth to higher trophic level, the δ15N significantly increased with growth in one species (Pacific cod), while not significant increase in the δ15N with growth in the remaining species.
The quantitative determination of fentanyl (FT) in serum was examined by isotope dilution analysis using a capillary gas chromatograph equipped with a surface ionization detector. The separation of FT and its deuterated analogue, FT-2H19, was achieved within 15 min a column temperature of 260°C by using a 25m column. Measurement of the samples prepared by the addition of a known amount of FT in the range of 0.2 to 40 ng/ml with 20 ng/ml of FT-2H19 to human control serum allowed observation of a linear relationship between the peak area ratio and the added amount ratio. The correlation coefficient obtained by regression analysis was 0.999. The advantage of the present isotope dilution method was demonstrated by comparison with other FT analogues which substituted a propionyl group with an acetyl group or a phenethyl group with a benzyl group as the internal standard. The present method was used to determine the serum level of FT in surgical patients after i.v. administration. No endogenous compounds and concomitant drugs interfered with the detection of FT or FT-2H19. This method was considered to be useful for the pharmacokinetic study of FT in patients.
Uranium and thorium contents of German rock salts were determined by neutron activation analysis. Mean contents of nine samples were 1.07 ppb and 96 ppt for U and Th, respectively. U thus was thought to be depleted and Th was enriched in the solid phase in evaporation of sea water. Similar tendency was observed for other halite samples in nature. These results are consistent with the existence of the stable uranyl tricarbonate anion in the solution phase.