In order for Bi2212 superconductors to exhibit good transport properties, they must be sintered at a high temperature, usually around 860℃. If the sintering temperature is too high, the performance of the superconductor will be deteriorated by the diffusion of the substrate components into the sample when the superconductor is applied to electronic devices. Therefore, we investigated the effect of calcination conditions on the transport properties of low-temperature sintered Pr-doped Bi2212 superconductor, aiming to prepare samples at a lower temperature (700℃) than in previous studies by controlling the number of sintering cycles.　　　 In this study, the composition of Bi2.05Sr1.89Ca1.06Cu2Li0.15Oy and Pr2O3 were added as additives, and the samples were sintered at 700℃ for one, two, and three times of calcination, respectively, and the resistivity temperature characteristics, crystal structure, and carbon concentration of the samples were measured. As a result, the sample calcinated one time showed no zero resistance, and the critical temperatures of the samples calcinated two and three times were 56K and 68K, respectively. The crystal structure of the sample sintered at 700℃ showed peaks similar to those of normal Bi2212. Furthermore, the amount of carbon in the samples decreased as the number of times of calcination was increased.

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We have fabricated cylindrical and pipe-shaped Bi2212 superconductor samples using Melt-Casting Process. The purpose of this research is to create a superconductor with high-quality transport properties, based on the idea that if a hole is made in the cylinder to form a pipe, the surface area of the sample increases, making it easier for the reaction to proceed during sintering. First, two superconductors with the same composition ratio of Bi2212 but different shapes were fabricated simultaneously. Then, (a) crystal structure, (b) composition ratio, (c) critical temperature, and (d) critical current of the fabricated cylindrical and pipe-shaped samples were measured and compared. In (a), the X-ray diffraction pattern and lattice parameter confirmed that a superconductor sample with the Bi2212 structure can be fabricated using MCP. In (b), the amount of impurity carbon was lower in the pipe-shaped sample, suggesting that the pipe-shaped sample had a larger surface area, which allowed sufficient reaction with oxygen during sintering. In (c), the pipe-shaped sample had a higher critical temperature, but the difference was not significant. In (d), it was found that the critical current density was higher in the pipe-shaped sample. The ratio of the superconducting phase is large, and it is considered that the material became a uniform superconductor.

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The calculation of response and limit Strength for traditional Japanese wooden structure often causes the structure collapse at 1st floor. To prevent the structure collapse at a given floor, the equation of every story deformation angle is required. The continuous column of heavy timber over than 180 mm square is proposed to average story deformation angles. In this paper, the calculation method for the section size of continuous columns is proposed. Results are as follows: 1) The calculation method for the section size of continuous columns consists of 2 equations: the equation for flexure capacity and the equation of difference between deformation angles. 2) The proposed method lessens the negative gradient of a Sa-Sd curve.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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