Study on Boron Steel (I)

Abstract

Synopsis:The purpose of boron treatment is to improve the hardenability of steel by addition of small emounts of boron less than 0.005%, and to save the alloying elements, nickel, chromium, and molybdenum. In Japan, there have been some basic investigations about the boron steel, but little experience in producing it.In order to promote the use of boron steel successfully, the authors believed, it was necessary to study the influence of boron addition on the steels specified in Japanese Industrial Standards.Effect of boron addition on the grain size, critical temperature, hardenability and mechanical properties of ease-hardening and constructional steels in JIS specification were studied by the use of small ingots. The results obtained were as follows;(1) It was found that the full deoxidation and nitrogen fixing by proper addition of Al and was necessary to increase the hardenability and to avoid the grain-coarsening tendency.(2) Effect of boron on the case-hardenability decreased as the carbon content increased. Maximum hardenability was obtained at about 0.9% C, and it was necessary to control the carburizing condition to avoid higher carbon content.(8) In the carburizing tests, the boron-treated steels behaved in the same manner as in the non-boron steels. It is presumed that boron itself had no significant effect on the carbon content and distribution of the case.

Liposome Mediated Delivery of Fluorescein Isothiocyanate Dextran into Yeast Protoplasts

“…Nagata et al reported the transfection of Saccharomyces cerevisiae protoplasts with liposome-encapsulated plasmid DNA, 8) and the delivery of 6-carboxyfluorescein into Sacch. cerevisiae protoplasts mediated by liposomes which were made of phospholipids extracted from the same yeasts was reported by Yamanaka et al 9 ) But the details of liposome protoplast interactions were left unknown. Therefore it seems valuable to find hether or not liposomes can introduce membrane-impermeable substances into yeast protoplasts, and if possible, to discover the factors which affect the efficiency of delivery of liposomal content into yeast protoplasts drastically.…”