[en] The development of multifilamentary superconductors is expected to realize electrical machinery and apparatus with high efficiency. The filament diameter df of superconductors being used for such AC applications is reduced to a level of submicrons or below to decrease AC loss. According to recent work on NbTi composite wires with ultrafine filaments, transition temperature T_c and upper critical field Bc2 decrease while critical current density J_c shows an anomalous maximum with decreasing df in the range of below 0.1 μm. The increase in J_c may be qualitatively explained by surface pinning and one-dimensional flux line lattice model. On the other hand, the proximity effect is well-known as one of the origins yielding such a decrease in T_c for fine filament superconductors covered with normal metals and depends on the superconducting filament size, the spacing between filaments, and the matrix material. In order to produce NbTi composite wires with high performance for AC use, the decrease in T_c and Bc2 for NbTi filaments of ∼0.1 μm must be suppressed and further wide data on NbTi composite wires which are different in filament size and matrix material would be required. In this paper, the dependence of T_c and Bc2 on df in NbTi composite wires, which are different in heat-treatment and matrix material, was presented. Further, their temperature dependences of Bc2 were obtained and analyzed by the GLAG theory to get the Ginzburg-Landau parameter κGL and thermodynamical critical field Bc

No abstract available

[en] Following studies on creep-fatigue behaviors of 304 steel at 650⁰C (Asada et al (1980) and Morishita et al (1984), (1985), (1987)), 2 1/4Cr-1Mo steel was studied on its creep-fatigue behaviors at 550⁰C in air and vacuum of 100 and 0.1 μPa. The present study intends to give a base for an evaluation of the environmental effect through obtaining a pure creep-fatigue behavior of this steel which is free from the environmental effect. In the previous studies on 304 steel, tests were conducted in three kinds of environment of air, 100 and 0.1 μPa vacuum. It seemed to be plausible that the 0.1 μPa vacuum shows the pure creep-fatigue behavior of 304 steel at 650⁰C which is almost completely free from the environment. A creep-fatigue life in 0.1 μPa vacuum is almost one order of magnitude higher than that in air. The 100 μPa vacuum suggested that the environmental effect of air still remains but is so small that a creep-fatigue life in 100 μPa is same to that in 0.1 μPa in some strain wave forms. The present study intends to examine if similar observations are obtained with 2 1/4Cr-1Mo steel at 550⁰C. This paper describes the analysis of the overstress and damages, in addition to a creep-fatigue result. (orig.GL)

[en] Creep-fatigue tests were conducted with 2 1/4Cr-1Mo steel at 550⁰C under various strain wave forms in air and vacuum of 100 and 0.1 μPa. No indication of environmental effect of air was observed in 0.1 μPa vacuum in which a strain rate effect diminished. However, there observed still a time/rate dependent life reduction in a case of wave forms with a longer tension going time than compression. In addition, there observed an effect of mean stress with this steel. An analysis of stress-strain response showed the response is not affected by the test environment. Internal stresses of back and drag stress were obtained with this steel and an overstress was predicted based on phenomenology. A pure creep-fatigue life reduction was predicted based on a damage model composed of the overstress. The prediction showed a scatter of a factor of two. An effect of air environment was evaluated based on the prediction procedure. The method should be improved to include the effect of mean stress on creep-fatigue behavior of this steel

[en] Actual gas supply into the ion source is modeled. Filling pressure is related to gas flow rate and conductance of the H^- extraction system. The rate equation for the H₂ molecule with gas inflow and outflow rates related with the filling pressure are employed in the numerical simulation of a negative hydrogen ion source. With the results of numerical simulation, the H number conservation relation and pressure balance equation are shown to be inaccurate especially for higher electron temperature. Actually for 5 eV of electron temperature, lost H₂ density amounts to 79% and the pressure becomes 5 times the original pressure of 5 mTorr. Even for a low pressure of 3 mTorr, the lost fraction is 67% for 5 eV of the electron temperature. This inaccuracy is large in high power and even for low pressure operation of the ion source. copyright 1996 American Institute of Physics

[en] Anticancer effects and biodistribution of a new lipophilic anticancer agent, estradiol-chlorambucil (KM2210), dissolved in lipiodol (LPD) were investigated as an intra-arterial chemotherapy (IAC) on Walker 256 carcinosarcoma grown in the liver of 136 Wistar rats. All rats treated with KM2210 (10 mg)-LPD survived for 90 days after administration, whereas none of the rats with LPD alone were alive for more than 19 days. Histological examination revealed that there was no viable tumor cell in the encapsulated necrotic tumor at 21 days after administration. There was no significant liver dysfunction or leukopenia due to KM2210. The biodistribution study using [14C, 3H]KM2210-LPD solution showed that KM2210 accumulated selectively in tumor and that the tumor-to-normal-liver and tumor-to-blood ratios were 10 and 1,000, respectively, at 21 days after administration. These results suggest that KM2210 has potential clinical application in the treatment of human liver cancer

[en] Cesiated volume sources which we call hybrid sources have been reported recently to show improved results for H^- production. Here we present results of numerical simulation, in particular the dependence on arc current, pressure and surface to volume ratio of H^- production in the hybrid source. The results agree well with experiments. ((orig.))