Evaporation experiments of metallic iron in vacuum

Evaporation experiments were carried out to examine evaporation kinetics of metallic iron, one of the important materials forming terrestrial planets and meteorites. Platelets of pure metallic iron were heated at temperatures ranging from 1075 to 1312℃ under vacuum (10^ to 10^ Torr) for 0.5 to 96 hrs. The evaporation proceeds by forming evaporation steps, although small wustite crystals were formed on the surfaces by partial oxidation of iron under vacuum. Amounts of evaporated iron estimated from mass loss of experimental charges increased with time at constant temperatures, showing a linear rate law. The evaporation rates, j, can be represented by ln j=22.21±2.29[mol m^s^]-390.6±29.2[kJ mol^]/RT. The evaporation coefficients, α_v, were obtained by comparing the experimental results with calculated rates using the Hertz-Knudsen equation. The value of α_v is close to unity if effects of partial oxidation are taken into consideration. The present results give basic information for discussing chemical evolution of the primordial solar nebula

Reflection of Metastable Atoms by a Glass Wall in a Positive Column Discharge Plasma

The leser-induced-fluorescence-spectroscopy (LIFS) method has been applied to a dc discharge plasma, and the radial density distribution of metastable ( 2 ¹S) helium atoms has been measured. It was found that the density did not tend to zero at the discharge tube wall. Rather, the density was about 20-30% of the value on the tube axis. By using the collisional-radiative model, we interpreted the result. As the origin of this finite population at the wall we considered two possibilities, namely, 1 ) the helium ions which recombine at the wall converted partly into the metastable atoms and 2 ) the metastable atoms were not quenched completely at the wall, but were reflected by a certain amount. We found that the first process could not reproduce the experimental population distribution, and that the second process with the reflection coefficient of the metastable atoms of 80-90% accounted for the experiment

The Inhibitory Effect of Conjugated and Polyunsaturated Fatty Acids on the Growth of Human Cancer Cell Lines

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