Kazuhisa Miura

Interaction of water with the surface of magnesium oxide

The adsorption isotherm of H2O has been measured on three kinds of MgO, and the bulk rehydration has been found to occur at a moderate pressure range of H2O, which exhibits a break in the isotherm. Infrared studies show that the surface hydration gives an isolated absorption peak at 3730 cm–1 due to free OH and a broad band centred at 3550 cm–1 due to hydrogen-bonded OH, whereas the bulk hydration exhibits a new absorption peak at 3695 cm–1. On evacuation, the bulk OH can be dehydrated at temperatures lower than those of the surface free OH. The exchange reaction of all kinds of OH with D2O was found to be slow. The initial bulk hydration necessitates a higher vapour pressure of ca. 4–6 Torr, but 3.5 Torr D2O is sufficient for the deuteration of bulk OH once formed. The successive exposure of the sample, having been subjected to the initial bulk hydration with H2O, to 10 Torr D2O causes an additional bulk hydration with D2O after a semi-complete surface deuteration, and gives rise to an increase in the peak intensities of lower-frequency bands in the OH stretching region.

Anomalies in standard gas adsorption isotherms of N2 and Ar on graphite at 77 K

Pronounced hysteresis due to pores, and a distinct step near a relative pressure of 0.4, appeared in the adsorption–desorption isotherms of N2 and Ar at 77 K for both natural graphite and natural graphite subjected to various treatments. The step stems from the adsorption of a second layer. By applying the same method as that used to determine Point B, the amount of gas adsorbed up to the completion of a second layer was read from the isotherm and the relationship between the surface area of pores and the amount of surface oxygen was investigated.

Automated Xe adsorption technique to measure small Brunauer–Emmett–Teller surface area of several square centimeters

An automated Xe adsorption apparatus has been developed that enables the measurement of a Brunauer–Emmett–Teller (BET) surface area of several cm2 with a repeatability of 4% (standard deviation). The apparatus is equipped with a differential type capacitance manometer, each hand of which is connected to a sample and reference adsorption cell having a symmetrical design, that is the temperature-compensated volumetric system which was reported by one of the authors [I. Suzuki, Rev. Sci. Instrum. 53, 1061 (1982); ibid., 66, 5070 (1995); ibid., 68, 4531 (1998)]. All procedures for measuring gas adsorption are computer controlled, and the coolant meniscus height is also computer controlled to keep the adsorption cell volume constant. A specially polished Si crystal rod was adopted as the standard sample. The BET surface area of the standard sample was measured by both the original temperature-compensated system and the newly developed automated system. Obtained results are fully consistent. We propose the adso...

Spreading area of molten lead-tin alloy on copper substrate and crystal growth of intermetallic compounds

In order to investigate the spreadability of molten lead-tin alloy on copper substrate, the variations of the spreading area and the thickness of intermetallic compounds formed were measured as a function of the change in the composition of the alloy at various temperatures. The spreading area revealed a maximum at a composition near 40 wt% Sn at 250°C, and the maximum shifted to higher concentration of tin when the temperature was raised, e.g., 62 wt% Sn at 400°C. The thickness of compounds formed was found to increase with increasing concentration of tin as well as with rising temperature of spreading. Especially, the crystal growth was remarkable at both ends of the concentration at 400°C, which gave a minimum in the thickness curve near 40 wt% Sn. The changes observed in the spreading area of the alloy as well as the thickness of the intermetallic compounds with time indicated that most part of the spreading was completed within the primary process of spreading.

Beyond administration in dormitory

Purpose – Aims to offer some ways of improving and developing the residents in the dormitory of Tsuyama National College of Technology, Tsuyama, Japan.Design/methodology/approach – Describes how in order to calm the dormitory atmosphere, strict regulations had been adopted since the foundation times for the college, which sometimes led to deplorable happenings. After facing dormitory issues from a new perspective in 1990, school authorities abandoned the allegiance to supervision. The dormitory affairs committee has stimulated the residents intrinsic motivation since then, leading to the improvements in the dormitory. Describes the course of improvement and the present condition of the dormitory.Findings – Advocates the necessity of broadening residents horizons to continually improve their quality of life in the dormitory.Research limitations/implications – It would take some years to ascertain our policy to be desirable for the dormitory. During that time, almost the entire membership of the dormitory...