The autoradiographical method was adapted for the investigation of the reactivity of the preadsorbed hydrogen or ethylene on Cu, Ni and Cu-Ni alloys prepared by various methods. 3H2and14C-ethylene were used as the tracers. The damage effect caused by α-rays and the effect of the sintering by the heat treatment upon the adsorption were observed. Massive alloys and the evaporated films deposited on the cold substratum were used for the tests. A great difference was found on the amount of the adsorbed hydrogen between the massive alloys and the evaporated films. The amount of adsorbed hydrogen increased by the damage of α-rays in the case of the massive metal and the film sintered at 250°C. However, the amount decreased in the case of the film sintered at 30°C. It was found that the amount of the adsorbed ethylene was not affected obviously by the composition of the alloy. These results suggested that the catalytic activity of metals depends maanty upon the structual factor rather than the electronic factor of the metals.
Radiopolarography is an analytical method of which use can be made for determining low concentration radioactive element without any nuisance of residual current. Radioactivity of the element deposited on mercury drop is measured and plotted against potential to get a curve similar to polarographic current-potential curve. Recently, A.A. Katsanos, et al, reported that radiopolarography can be extended to nonradioactive element in the presence of a radioactive element due to oxidation-reduction replacement. For example, using radioactive65Zn and natural Mn2+radiopolarographic waves are obtained at the corresponding half-wave potentials of -1.00 and -1.51 V vs. S.C.E., respectively. The depositd manganese is oxidized and replaced by radioactive zinc and gives rise to the second plateau; (Hg, Mn) +Zn2+= (Hg, Zn) +Mn2+ The height of the first plateau is proportional to the concentration of Zn2+and the difference between those two plateaux is proportional to the concentration of Mn2+and independent of that of Zn2+, thus allowing the quantitative determination of Mn2+. In the present experiment, the authors report a new type cell which is made of two separated cells (Fig. 1) : in the first cell, there is a solution of non-radioactive element (Mn2+), and in the second cell, there is a solution of radioactive element (65Zn2+) . Mercury drops with electrodeposited manganese in the first cell fall into the second cell, in which it is oxidized and replaced by65Zn2+. So, the labeled mercury drops give a polarographic plateau the height of which is quantitatively proportional to the concentration of manganese.
The most of chemical methods for determination of mercury in gas camprises of collection of mercury from large volume of gas and of estimation of the amount of mercury collected. Dithizone method seems to have many merits for determination of small amount of mercury, but it is interfered by many kinds of impurities. Neutron activation analysis is suitable to the determination of mercury of low concentration because of the high sensitivity. For the development of the method of determination, the radioisotope tracer technique and activation analysis are very useful. Thus, we established the following method and analytical results were compared to those by dithizone method and gas detector tube method. In this method absorbent is saturated chlorine solution and absorption time is 2 hrs. After absorption, 4 ml of conc HNO3aqis added to the absorbent, and the mixture is concentrated to 8 ml, then it is sealed in the quartz capsule. Irradiation is carried out in HTR with neutron flux of 1.2×1011n/cm2⋅sec for s hrs. After cooling for loo hrs., samples are taken out from capsule and determined by the non-destructive method. The sensitivity of this method is 10-3mg/m3. However the sensitivity can be improved by use of irradiation with higher neutron fluxes and destructive methods.
A113mIn generator by the column of SnS2precipitated on the anion exchange resin was prepared. This utilizes the isotopic exchange reaction between SnS2and113Sn solution. The long-lived parent113Sn was loaded on the column and the short-lived daughter113mIn was eluted out with 0.1-0.01M HCI. In each milking sequence, the leakage of113Sn was found to be always of the order from 10-3to 10-4per cent of the original activity during the passage of 1l of the effluent through the column. The yield is about 20 per cent of the113mIn on the column. The radiochemical impurities, 60Co and114mIn present in113Sn sample, are removed by this method.
Radioactive contamination protective paint is particularly desired to have quality of small contaminability and large decontaminability. Using233UO2 (NO3) 2acidic aqueous solution as radioactive contamination, it has been examined that kinds, manufacturing methods and components of paints and coating surface conditions influenced on their protective qualities. Results showed that some kinds of epoxy resin paints and vinyl chloride resin paints and also chlorinated rubber paint gave small contaminabilities and large decontaminabilities. After that, microscopic observation (168 magnifications) indicated these coating surfaces were compact and ordered surfaces, respectively. In addition, phenol resin paint and acryl resin paint gave comparatively good results.