Superconductive current lead has been prepared by the TFA-MOD processed YBCO tapes. That is composed of 12 YBCO tapes having critical current (Ic) of around 100 A at 77 K. The tapes are 4.5 mm in width, 200 mm in length and about 120 μm in thickness. The 1 μm thick superconductive YBCO layer is formed on HastelloyTM substrate tape with buffer oxide layers through the TFA-MOD process. The 12 YBCO tapes are arrayed on the both sides (6 tapes on one side) of the stainless steel board with 3mm in thickness for a board type. They are similarly soldered to copper caps at the both ends.The transport current of 1,000 A was stably applied for 10 minutes 77K without any voltage. The transport current of 1,200 A was successfully applied without quenching. The voltage between both copper caps linerly increased with increasing the transport current, and it was about 300μV at the applied currents of 1,000A. The overall thermal conductivity of the current lead composed of YBCO tapes and stainless steel board is much lower than that of non-superconducting current leads. Therefore, the present current lead with small heat leakage seems to be practically promising for superconducting magnets.
The carbon nanotube (CNT) was added into polarizable electrode instead of the acetylene black (AB) as conducting material of the coiled EDLCs. The capacitance of the EDLCs with addition of the CNTs or the ABs are almost same value.The series resistance of CNT-added EDLCs is lower than that of AB by 30[%]. Therefore, it is effective to add the CNTs into polarizable electrode as conducting material of the coiled EDLCs.
MgB2 superconducting thin wires have been prepared by in-situ powder-in-tube process. Using Magnesium hydride MgH2 and amorphous B powders with SiC nano-sized powder addition, SS/Fe/MgB2/ steel composite wires of 0.53 mm ∼ 0.19 mm in diameter have been fabricated through grooved rolling and drawing. The stainless steel sheath was hardened to a Vickers hardness of around 600 Hv by cold drawing. The Ic at 4.2 K and self-field for the MgB2 wire of 0.53 mm in diameter without SiC addition is 200 A, which corresponds to the critical current density (Jc) of 4,300 A/mm2. The MgB2 composite thin wires sheathed with low thermal conductive metals are promising as current leads with small heat leakage in liquid hydrogen.
High temperature oxidation behavior of Ni-20Cr and Ni-20Cr-1Si alloys with small amounts of rare earth elements (Y, Lu) was studied in oxygen for 18ks at 1473 and 1573K, by mass gain measurements, observation of surface appearance, X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The mass gains of the Ni-20Cr alloys with 0.5% rare earths (Y, Lu) and/or 1%Si decreased at both the oxidation temperatures. Granular Cr2O3 particles on Ni-20Cr-(0.05, 0.1, 0.2, 0.5)Y(Lu) and Ni-20Cr-1Si-(0.05, 0.1, 0.2, 0.5)Y(Lu) alloys decreased in size with increasing Y(Lu) and increased with increasing oxidation temperature.
An experimental investigation has been made on the flow in a natural convection loop. Time series data of temperature oscillation were obtained for various types of the flow. Based on these data, attractors in high-dimensional space have been reconstructed by obtaining optimum delay time. The correlation dimensions Dc for these attractors were calculated by the method of correlation integration and plotted against heat inputs. The values of Dc could be classified into three regions according to the value of heat flux q, 1) Dc ≥ 13 in the laminar region (q ≤ 4.13kW/m2), 2) 1.1 ≤ Dc ≤ 2.4 in the unstable region (5.51 ≤ q ≤ 22.0), and 3) Dc ≥ 11.5 in the turbulent region (q ≥ 23.4). The values of Dc are non-integer in all regions. These results are consistent with chaotic characteristics. Observed in detail, however, the region 2) contains three types of flows: Turbulent, unstable with and without flow reversals. The last one was considered to be unstable flow in spite of non-reversal, because of its small Dc.
In order to develop a brief assessment system of sleep stage for untrained users utilizing water mat pressure sensors placed in a bed, polysomnographic(PSG) recodings were compared to data obtained by present sensor. Coincident ratio were calcurated using estimated sleep stage by the sensor and polysomnographic judgement. Results showed that sleep diagram by present sensor was consistent with that by PSG.
In order to utilize for automobile body applications, poly-methyl methacrylic acid (acrylic resin, PMMA) composites dispersed by Al-powders was prepared by solution-casting, which could easily control the dispersion ratio. Although the Al addition gradually decreased the impact value, it radically enhanced the electrical conductivity at the critical volume fraction in polymer. The jump of electrical conductivity was observed at the critical volume fraction of the Al addition. Based on the percolation theory, the result was explained.
Referring to the reflection type four detector photopolarimeter developed by R.M.A. Azzam, we have fabricated transmission type four detectors photopolarimeter (T-FDP). Simulations of the polarization states were carried out for the T-FDP. Simulated results were compared with measured values for the arbitrarily polarizations.
A fiber optic bio-sniffer for high-selective alcohol vapor monitoring with an UV-LED was constructed and tested. Since many kinds of chemical components are transpired from human bodies, high-selective gas sensor is strongly requested. In order to achieve high selectivity, the sensor utilizes fluorescence of nicotineamide adenine dinucleotide (NADH) (491nm), which is produced by the enzymatic reaction of alcohol dehydrogenase (ADH). The bio-sniffer was fabricated by attaching a wet enzyme immobilized membrane to the fiber-optic NADH measurement system. The fluorescent intensity significantly increased with a stable value related to the ethanol gas concentration when ethanol vapor was exposed.