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Perovskite-type oxides containing transition metals are attracting great attention as catalysts for complete oxidation of hydrocarbons as well as electrochemical reduction of oxygen (1). A s far as I know, the use of perovskite-type oxides as catalysts was first reported by Meadowcroft in 1970 (2) for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al. (3) reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many studies thereafter which are related to exhaust control catalysts and electrode catalysts.

Perovskite-type oxides containing transition metals are attracting great attention as catalysts for complete oxidation of hydrocarbons as well as electrochemical reduction of oxygen (1). A s far as I know, the use of perovskite-type oxides as catalysts was first reported by Meadowcroft in 1970 (2) for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al. (3) reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many studies thereafter which are related to exhaust control catalysts and electrode catalysts.

Optical properties of color centers in MgO single crystals irradiated by fission neutrons (Kyoto University Reactor, KUR) and by 14 MeV neutrons (RTNS-II, at Lawrence Livermore National Laboratory, LLNL) have been investigated. The absorption spectra of MgO crystals irradiated by neutrons from the two different sources are similar; exhibited principal bands are 250 nm band consisting of F and F + bands, 352 (F 2 center), 570 and 975 (F 2 center) nm bands. In the samples irradiated by fission neutrons, the absorption intensity of the 570 nm band does not reach a maximum by neutron fluence through which the F and F 2 type bands reach a maximum. These phenomena are remarkable in the impurity-doped samples. A linear increase of the intensity of the 570 nm band with a dose of fast neutrons does not change with impurity contents, and exists in the extensive range examined of fast neutron dose (10 15 –10 19 n/cm 2 ). This fact suggests that the crystalline MgO can be applied as a fluence monitor for fast neutrons with extensive energy.

A study was made on the catalysis of supported platinum particles as a function of their size, namely, the activities for isomerization, dehydrocyclization, dehydroaromatization, and hydrocracking of hydrocarbons were investigated with various platinum sizes made by heat treatment. The observations of particle shape and size were carried out by means of both electron microscopy and hydrogen chemisorption technique. Correlations have been pursued between the platinum dispersion and the product distribution from n-heptane and methylcyclohexane. (change-para-here) Fine platinum particles below 15 A in diameter were highly active for reforming of hydrocarbons to give iso-heptanes and dimethylcyclopentanes. Some discussions about the influence of support properties on activity and selectivity were also presented.

A new thermochemical water-splitting process named “Sb-I-Ca Process” is described with relevant thermochemical data and preliminary experimental results. The process, which is an improved version of the “Sb-I Process” previously proposed, consists of basic steps of five reactions and three phase-transitions. It was found that all reaction- and separation-steps in this process could be conducted without serious difficulties. From a flow diagram made on the basis of the experimental results, the overall efficiency was estimated to be about 40% with an assumption of 70% heat recovery.

MICROSCOPIC examination of highly radioactive fall-out particles, produced by the series of large-scale nuclear test explosions carried out during September and October 1961, revealed that although they were quite or nearly spherical, their surface states were different from particle to particle and some of them were much creased or had small spherical particles attached to their surface1. Electron microscopic examination followed by electron photomicrography has been carried out to examine their surface state in detail. A vacuum-evaporated silica film backed with evaporated carbon film was used for holding a sample particle. A small drop of benzene was put on the silica film which was supported on a 150 sheet mesh, then a sample particle which had been picked up by the tip of a fine needle was transferred into the drop seen under a microscope. The sample particle was left on the film after the drop evaporated out. Electron photomicrographs of four particles, A, B, C and Z, were taken. In Table 1 are given their diameters, radioactivities and fractionation factors for 141Ce + 144Ce (ref. 2). Fig. 1 (1,2,3) gives electron photomicrographs of particles A, B and C, respectively. Small particles adhered to the surface are thought to be fine fall-out particles which are micron size or smaller3. Fig. 1 (5) is a close-up of a part of particle C. The diameter of this small particle is about l.4µ.

After the single crystals of CsH2PO4 and CsD2PO4, were irradiated by γ-rays, their dielectric constants, spontaneous polarizations and heat-capacities were measured with various doses radiated up to 600 MR. Their magnitudes decrease, and their Curie temperatures shift toward lower temperatures; especially, it should be noted that the heat capacities decrease not only in TT C. The results are discussed based upon some theoretical models.