Magnetic properties of La2Co17-x-yFexTiy and La2Co17-x-yFexTiyNδ

The magnetic properties of La₂Co_17-x-yFe_xTi_y and La₂Co_17-x-yFe_xTi_yN_δ intermetallic compounds have been investigated. La₂Co_17-x-yFe_xTi_y has the rhombohedral Th₂Zn₁₇ structure and exhibits the following magnetic properties: saturation magnetization >1.0 T; Curie temperature >873 K; and easy c-axis. Nitrogen is introduced into these compounds interstitially through the nitrogenation process. The saturation magnetization and Curie temperature of La₂Co_17-x-yFe_xTi_yN_δ is decreased by the introduction of nitrogen, in contrast to Sm₂Fe₁₇.     

Glycosaminoglycan binding properties of annexin IV, V, and VI

We have previously demonstrated that annexin IV, one of the calcium/phospholipid-binding annexin family proteins, binds to glycosaminoglycans (GAGs) in a calcium-dependent manner (Kojima, K., Yamamoto, K., Irimura, T., Osawa, T., Ogawa, H., and Matsumoto, I. (1996) J. Biol. Chem. 271, 7679-7685). In this study, we investigated the GAG binding specificities of annexins IV, V, and VI by affinity chromatography and solid phase assays. Annexin IV was found to bind in a calcium-dependent manner to all the GAG columns tested. Annexin V bound to heparin and heparan sulfate columns but not to chondroitin sulfate columns. Annexin VI was adsorbed to heparin and heparan sulfate columns in a calcium-independent manner, and to chondroitin sulfate columns in a calcium-dependent manner. An N-terminal half fragment (A6NH) and a C-terminal half fragment (A6CH) of annexin VI, each containing four units, were prepared by digestion with V8 protease and examined for GAG binding activities. A6NH bound to heparin in the presence of calcium but not to chondroitin sulfate C, whereas A6CH bound to heparin calcium-independently and to chondroitin sulfate C calcium-dependently. The results showed that annexin IV, V, and VI have different GAG binding properties. Some annexins have been reported to be detected not only in the cytoplasm but also on the cell surface or in extracellular components. The findings suggest that the some annexins function as recognition elements for GAGs in extracellular space.     

Divinylbenzene-crosslinked terpolymer consisting of hemin,styrene, and 2-methyl-5-vinylpyridine as cyanide ion exchanger. Preparation of the polymer in the form of beads by suspension polymerization

Bead-shaped, divinylbenzene-cross-linked terpolymers, consisting of hemin (ferri-protoporphyrin IX chloride), styrene, and 2-methyl-5-vinylpyridine, were prepared by suspension polymerization in which all or part of styrene monomer was replaced with divinylbenzene. Analogous terpolymers of the cross-linked and uncross-linked formless types were also prepared by solution polymerization. All the terpolymers obtained were characterized by electron spin resonanance spectroscopy, scanning electron microscopy, and measurement of specific surface area. The characteristic of the adsorption of cyanide ion onto the terpolymer beads was investigated and compared with those adsorbed onto their analogs. The column separation of cyanide ion with the terpolymer beads was carried out to examine the ion-adsorbing capacity. It was found that the suspension polymerization is just appropriate to prepare a cyanide ion exchanger in the form of beads.     

Degradation of poly(acrylamide) in aqueous solution by glow discharge electrolysis

Summary The glow discharge electrolysis was carried out to an aqueous solution containing poly(acrylamide). The analytical results of the degradation products showed that the degradation takes place stepwise caused by the cleavages of the main and also the side chains of the polymer.     

Solubility study on protective oxide films in molten chlorides created by refuse incineration environment

Solubility measurements of Cr₂O₃, NiO, Co₃O₄, Fe₃O₄ and SiO₂ in molten NaCl‐KCl at 727 °C and NaCl‐KCl‐Na₂SO₄‐ K₂SO₄ at 550 °C were conducted in three different levels of basicity. The dissolution behavior of the oxides in the molten chlorides showed almost the same tendency as that shown in the result in molten Na₂SO₄ obtained by other researchers. In refuse incineration environment, protective Cr₂O₃ film is easily changed into CrO²⁻₄ by molten chlorides contained in deposits because the basicity of the molten chlorides is made more basic by the effect of H₂O in the combustion gas. In order to improve corrosion resistance of alloys, it would be better to add some elements such as Mo, V or W, which are expected to reduce the solubility of Cr₂O₃, and/or some elements such as Si or Ni, which are expected to produce protective oxide films having low solubility in a basic solution.     

Synthesis of HCP, FCC and BCC structure alloys in the Mg–Ti binary system by means of ball milling

Mg_xTi_100−x (35 ≤ x ≤ 80) alloys with hexagonal close packed (HCP), face centered cubic (FCC) and body centered cubic (BCC) structures were successfully synthesized by means of ball milling. Mg_xTi_100−x alloys with a BCC structure at x = 35 and 50 and with a HCP structure at x = 80 were synthesized by milling of Mg and Ti powder using stainless steel milling balls and pots. At x = 65, the BCC and HCP phases were synthesized. Mg_xTi_100−x alloys with a FCC structure were synthesized at x = 35 and 50 by milling using zirconia milling balls and pots. The FCC and HCP phases were synthesized at x = 65 and 80 using zirconia milling balls and pots. The crystal structure of Mg_xTi_100−x alloys synthesized by the ball milling method depended on the materials of milling balls and pots. That indicates that milling products are determined by the dynamic energy given by the milling setup. The lattice parameters of Mg_xTi_100−x in the HCP, FCC and BCC phases increased with increase of the Mg content, x.     

Mechanism of lower oxidizability of eicosapentaenoate than linoleate in aqueous micelles. II. Effect of antioxidants

We have reported that the peroxyl radicals derived from methyl eicosapentaenoate (20:5n-3) are more polar than those from methyl linoleate (18:2n-6) since the former peroxyl radicals have at least two molecules of oxygen in a molecule while the latter peroxyl radical has one. This lowers the oxidizability for 20:5n-3 in aqueous Triton X-100 micelles by enhancing the termination reaction rate for peroxyl radicals and by reducing the rate of propagation since there may be more polar peroxyl radicals derived from 20:5n-3 at the surface than within the micelle core. In this study, we measured the effect of three antioxidants, di-tert-butyl-4-methylphenol (BHT), 2,2,5,7,8-pentamethyl-6-chromanol (PMC) and 2-carboxy-2,5,7,8-tetramethyl-6-chromanol (Trolox), on the oxidation of lipids in aqueous micelle. Antioxidants give a clear induction period during oxidation of 18:2n-6 initiated with a water-soluble radical initiator, and its induction length decreases in the order of BHT>PMC>Trolox. This is consistent with the proposed location of three antioxidants: being in the core of micelle, at the surface, or in aqueous phase, respectively. However, BHT does not inhibit the oxidation of 20:5n-3 efficiently, and its rate of oxidation is slower than that observed in the oxidation of 18:2n-6, supporting the idea that polar peroxyl radicals derived from 20:5n-3 are preferentially located at the surface of the micelle. Similar results were obtained when oxidation was initiated with a lipid-soluble radical initiator except antioxidants had lesser effect on the oxidation rate of 20:5n-3.     

Irradiation test of component for radiation-resistant small sized motor

A small-sized motor with a resistance to radiation was developed. This motor has been able to operate at a gamma-ray dose of a value 700 times as high as the specification of a commercial motor. The present work describes results of post-irradiation examinations (PIEs) to evaluate effects of neutron irradiation on the lifetime of some major components of the motor such as a bearing, a magnet and a fixation agent for a field coil wire. It became clear from the results of PIEs that the radiation-resistance dose of the motor using a Sm–Co magnet will be expected to be one order of magnitude higher than that of the motor using a Nb–Fe–B magnet.     

Carbonation of low heat portland cement paste precured in water for different time

The carbonation technique was applied to accelerate the hydration of low heat portland cement （LHC）. Before carbonation, the demoulded pastes were precured in water for 0, 2, 7, and 21 d, respectively. The results show that precuring time in water strongly influences the carbonation process. The phenolphthalein test indicates that the paste precured in water for a shorter time is more quickly carbonated than that for a longer time. The content of calcium hydroxide increases with increasing the precuring time in water, whereas, the amount of absorbed carbon dioxide changes contrarily. Scanning electron microscope （SEM） observation shows that portlandite always fills up big air bubbles in the paste during precuring in water, and the mercury intrusion porosimetry （MIP） results show that there are less large capillary pores in the paste precured in water for a longer time. It is found that the paste without precuring in water has more carbon dioxide absorption during curing in carbon dioxide atmosphere, and its total pore volume decreases remarkably with an increase in the carbonation time than that precured in water. X-ray diffraction （XRD） and Brunauer-Emmett-Teller （BET） surface area analyses indicate that the carbonate products are vaterite and calcite; CxSHy formed from carbonation has low BET surface area in comparison with that of C-S-H formed from curing in water.