Hidekazu Okuhira

Hydrogen absorption of LaNi5 after LiOD treatment and surface characterization by TOF-SIMS

Abstract In the hydrogen absorption reaction, the surface condition is a predominant factor. The surface oxide layer generally prevents the dissociative absorption. Recently we reported the effect of the pretreatment by LiOH, which enhanced the hydrogen absorption even after significant surface oxidations. In this study the surface of LaNi 5 alloy treated with a LiOD solution was analyzed by TOF-SIMS. The reaction mechanism of the accelerated absorption by the alkaline treatment is discussed.

Quantitative Analysis of Trace Hydrogen in Highly Purified Nitrogen Gas Using Rapid Reactions in Atmospheric Pressure Ionization Mass Spectrometer

Quantitative analysis of trace hydrogen in highly purified nitrogen gas for the semiconductor fabrication process was investigated using an atmospheric pressure ionization mass spectrometer (APIMS). A previous method wherein the sample gas is directly introduced into the APIMS is not capable of providing high-sensitivity measurements for hydrogen in nitrogen gas. By mixing 20% argon gas with the sample gas, the sensitivity was increased to ten times that of the previous method. This is due to the occurrence of a previously unreported rapid reaction through which the quantity of hydrogen ions is increased: (N2Ar)++H2→N2H++H+Ar. The detection limit in this method and the rate constant for this reaction were estimated to be 40 ppt and 1.4×10-10 molecule-1 cm3 s-1, respectively.

ToF-SIMS characterization of molecular ions from Fomblin Z-DOL on Ag substrates

Abstract There is great difficulty to obtain molecular ions from the lubricant actually as films on magnetic recording disks. With the assistance of Ag cationization, quasi-molecular ions of (Ag+M)+ from Fomblin Z-DOL cast on Ag substrate were successfully observed on the positive time-of-flight secondary ion mass spectrometry (ToF-SIMS) spectra. Considering the mass interference between oligomers, detailed distributions of molecular weight (Mn) and monomer ratio (m/n) could be extracted. The average values of Mn and m/n obtained by ToF-SIMS are in good agreement with other conventional technique such as nuclear magnetic resonance spectroscopy (NMR).