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The determination of the block sequence of triblock copolymers is difficult without information on the synthetic conditions, such as starting materials and reagents used or analysis using tandem ma...

We proposed the air-core cyclotron using high-temperature superconducting (HTS) technology, named Skeleton Cyclotron, as high intensity compact, variable-energy and multi-particle cyclotron for RI production. Skeleton Cyclotron consists of HTS split circular main coils generating the isochronous field and HTS non-circular sector coils generating the azimuthally varying field (AVF). Now, we are currently developing the small-scale cryocooler-cooled HTS coil system of Skeleton Cyclotron, which accelerates the proton up to energy of 5 MeV at an extraction radius of 20 cm. Skeleton cyclotron is multi-coil system consists of HTS split circular main NI (no-insulation) coils and HTS non-circular sector NI coils. Therefore, the electromagnetic, thermal, and mechanical behaviors are expected to be very complicated. In this study, the structure analysis based on finite element method using COMSOL Multiphysics is performed for a non-circular sector coil. The coils in Ultra-Baby Cyclotron are reinforced with YOROI-coil structure. Therefore, the effect of YOROI-coil structure was numerically investigated during cool-down process and excitation process. YOROI-coil structure is effective for non-circular sector coil against the electromagnetic force.

We have been studying no-insulation (NI) high temperature superconducting (HTS) coils that do not use turn-to-turn electrical insulation. The no-insulation winding technique can provide high stability of the HTS coils against the quenching, but it cannot prevent mechanical deterioration of the HTS coil due to electromagnetic force and multiple cooling. To solve these problems, we propose the installation of metal protection ring on the outermost turn of NI HTS coil to improve thermal, mechanical, and electrical stability. In this study, the current bypass characteristics in the transverse direction within an NI test coil wound with 37 turns of REBCO wire with/without copper protection ring were experimentally investigated for various amounts of heating by a heater and various heater positions. Eight repeated cooling experiments with liquid nitrogen proved that the proposed copper protection ring was effective against shape deformation of the NI test coil and deterioration of contact resistance between turns due to thermal stress.

To achieve high-field rare-earth barium copper oxide (REBCO) coils, the mechanism of the deterioration of or damage to such coils needs to be clarified. A REBCO coil experiences various stresses and strains during the winding, cooling down, charging, and discharging processes. Furthermore, the additional force and stress due to a screening current has become an issue in REBCO coils. To protect REBCO coils from large electromagnetic stress in a high field, a reinforcement structure called the Y-based oxide superconductor and reinforcing outer integrated (YOROI) coil was proposed. This study numerically evaluated the effect of the YOROI coil structures against thermal and electromagnetic stress using a two-dimensional axisymmetric structural analysis. This simulation considered the following: 1) the mechanical stress induced by 10 N of winding tension, 2) thermal stress during cooling from 300 K to 10 K, and 3) electromagnetic stress, which included the additional stress due to a screening current during the charging process. The mechanical behavior due to each process was investigated, and the effect of the YOROI structures was also examined.

The characteristics of no-insulation high-temperature superconducting (HTS) manet is dominated by the magnitude of the turn-to-turn contact resistance. A few techniques have been proposed to increase the turn-to-turn contact resistance. The relation between the turn-to-turn contact resistance and the magnet stability has also been investigated in simulations. Although the turn-to-turn contact resistance measurement was only the sudden-discharging method before, we proposed a low-frequency-AC current (LFAC) method. Using our proposed method, it is possible to measure the turn-to-turn contact resistance under various conditions. In a previous paper, we measured it when charging DC current to a single pancake coil. In this paper, the turn-to-turn contact resistance was measured by the LFAC method when an external field of 1-3 T was applied to a single pancake coil. The coil strain was also measured, and the relation of the turn-to-turn contact resistance and the coil strain was also discussed.

A wireless power transmission (WPT) system using the high temperature superconducting (HTS) coil for a railway vehicle is required to transmit the electric power of several hundred kW in a short time (60 s). In order to design the WPT system using HTS coil with the thermal stability, and it is necessary to clarify the thermal characteristics of the HTS coil at the operating current in kHz band and the operating conditions considering thermal stability in the WPT system. We analyzed the frequency characteristics of the critical current in the HTS coil above 1 kHz and investigated the operating conditions considering thermal stability in the WPT system for the railway vehicle using HTS coil in liquid nitrogen. As a result, the critical current of the HTS coil in the kHz band decreased with the frequency. This is because the AC loss in the HTS coil increased with the frequency, and the critical current density of the HTS coil decreased with increasing the surface temperature. In order to design the HTS coil with thermal stability in the kHz band, and it is necessary to operate the HTS coil on alternating current less than about 50% of the critical current measured by direct current. We found that the thermally stable WPT system capable of fast charging for 60 seconds can be realized by operating current at the frequency of about 2 kHz.

In this paper, we investigated a large-capacity Wireless Power Transmission (WPT) system operating in the kHz frequency band using high-temperature superconducting (HTS) coils for a railway vehicle. We analyzed the ac losses of the HTS coils using finite element method (FEM) and obtained the transmission efficiency at the power transmission of 38.7 kW at 0.8 and 4.3 kHz. As a result, we clarified that the transmission efficiency between the primary HTS coil and the secondary HTS coil of the WPT system for the railway vehicle is more than 90%. The heat generation in the coils can be suppressed by using the HTS coils for the WPT system. The ac losses per cycle (J/cycle) increased as operating frequency decreased since the HTS tape length increased with the lower operating frequency to achieve the same power transmission. However, the total loss per unit time (W) of the HTS coils did not nearly increase with the frequency. This result suggests that the WPT system using the HTS coil can be operated at the low-frequency region around 1 kHz. The system efficiency including the cryocooler power loss was lower than the transmission efficiency using copper coils. However, the analysis result shows that, if the critical current density of a commercial HTS tape at 77 K increases by approximately four times, the WPT system with HTS coils can realize a higher-efficiency and longer-time operation in a low frequency region of kHz than the system with the copper coils.

We have investigated the application of a high-temperature superconducting (HTS) coil to a high-power wireless power transmission system operated in the frequency region less than 10 kHz. In order to reduce the ac loss of the HTS coil, it is necessary to clarify the characteristics of magnetization loss in the HTS tape with a copper layer in the kHz frequency band. Therefore, we prepared GdBCO tapes with and without the copper layer and measured the magnetization loss of the GdBCO tape exposed to a vertical magnetic field in the kHz frequency band. We analyzed the ac losses of the GdBCO layer, the copper layer, and the other layers within the tape by a finite element method analysis. The influence of the copper layer thickness on the ac loss in each layer was investigated by a finite element method (FEM) analysis. The magnetization loss per cycle of the GdBCO tape slightly decreased with the frequency. The magnetization loss, however, can be approximately estimated by Brandt's formula with a certain accuracy when the n value of the tape is large. In the GdBCO tape with the copper layer, when the external magnetic field was large, the magnetization loss per cycle of the GdBCO layer was larger than the copper layer loss. The magnetization loss, however, decreased and the copper layer loss increased with the thickness of the copper layer. The total loss of the GdBCO tape can be reduced by placing the coppers layer near the GdBCO layer.

Wireless power transmission has been investigated to realize more efficient and more convenient noncontact power transmission systems for electric tramways, electric vehicles, portable telephones, and so on. Since the magnetic resonance type wireless power transmission system is often used in frequency regions of megahertz, there are some problems, such as the increase of wire resistance due to skin effect and a switching loss in converter. Therefore, it is expected to realize high-power wireless power transmission in low-frequency regions of kilohertz. In a wireless power transmission system using copper coils, however, the transmission efficiency decreases with the decrease of resonance frequency because quality factor decreases with the decrease of the resonance frequency. Therefore, we fabricated a model system using high-temperature superconducting (HTS) double-pancake coils composed of REBCO tape and investigated the transmission efficiency characteristics to evaluate the possibility of application of the HTS coil to a high-efficiency wireless power transmission system operated in the low-frequency region of kilohertz. In the copper coil system, the transmission efficiency increases with the resonance frequency. In the HTS coil system, however, a high-efficiency transmission was obtained, even at a low-resonance frequency, due to a large quality factor at low frequency. Moreover, in the wireless power transmission system using HTS coils, the transmission efficiency was high not only at the resonance frequency but also around the resonance frequency. From these results, we believe that HTS coil can realize the high-efficiency wireless power transmission in a low-frequency region of kilohertz.

The oxidation of oil starts, in general, from the penetration of atmospheric oxygen into oil. Inhibition of the vigorous oxidation of oil at deep-frying temperature under carbon dioxide flow, by disrupting the contact between oil and air, was first demonstrated using oil in a round bottom flask. Next, the minimum carbon dioxide flow rate necessary to blanket 4 L of frying oil in an electric fryer (surface area 690 cm(2)) installed with nonwoven fabric cover, was found to be 40 L/h. Then deep-frying of potato was done accordingly; immediately after deep-frying, an aluminum cover was placed on top of the nonwoven fabric cover to prevent the loss of carbon dioxide and the carbon dioxide flow was shut off. In conclusion, the oxidation of oil both at deep-frying temperature and during standing was remarkably inhibited by carbon dioxide blanketing at a practical flow rate and volume. Under the deep-frying conditions employed in this study, the increase in polar compound content was reduced to half of that of the control.

Bis(triethoxysilyl)propane (BTESP) is a bridged-type organoalkoxysilane with a Si-C3H6-Si bond. It was utilized for membrane fabrication via a sol-gel method to achieve high permselectivity for large molecules. Membrane fabrication parameters such as the acid molar ratio (AR) in the sol and calcination temperature were evaluated for their effect on the network pore size and on gas permeation properties, as evaluated by the molecular size dependence (0.26–0.55 nm) and temperature dependence (50–200 °C) of gas permeance. BTESP membranes with different ARs (10−1, 100, and 10) showed H2/N2 and H2/CF4 selectivities of 20–30 and 640–32,000, respectively. As AR was increased, each gas permeance also increased, but H2 selectivity that corresponds to network pore size was decreased. FT-IR analysis indicated that the density of the Si-OH groups (Si-OH/Si-O-Si) of unfired gels was decreased with a higher AR, so that condensation of the Si-OH groups during the calcination process formed a dense network structure in the case of BTESP membranes with a low AR (10−1). Calcination temperature also affected the network structure of BTESP membranes. BTESP membranes calcined at different temperatures (350, 450, and 600 °C) showed H2/N2 and H2/CF4 selectivities of 10–30 and 410–32,000, respectively. A BTESP membrane calcined at high temperature (600 °C) showed loose networks since the linking units derived from BTESP were decomposed at temperatures above 500 °C, which resulted in the formation of methyl groups. In conclusion, the AR in a sol is suitable for tuning small pore sizes, while calcination temperature as a membrane fabrication parameter offers the advantage of controllability for loose network structures.

Mg3TeO6-type Ca0.8Y2.4Sn0.8O6 has been found as a new structure family of oxide-ion conductors. From bond-valence-based energy (BVE) calculations for 147 compositions, which contain tin (Sn) as an essential element, Mg3TeO6-type Ca0.8Y2.4Sn0.8O6 was found to have a low energy barrier for oxide-ion migration. Ca0.8Y2.4Sn0.8O6 was synthesized by the solid-state reaction, and its electrical conductivity and crystal structure were investigated. The total electrical conductivity at various partial oxygen pressures and band gap estimated from the UV-vis spectrum suggested that Ca0.8Y2.4Sn0.8O6 is a pure oxide-ion conductor. The activation energy for the oxide-ion conductivity of Ca0.8Y2.4Sn0.8O6 was 1.39(4) eV. Synchrotron X-ray powder diffraction data of Ca0.8Y2.4Sn0.8O6 at 300 and 1273 K were successfully analyzed with the Mg3TeO6-type structure. The BVE calculation using the refined crystal structure of Ca0.8Y2.4Sn0.8O6 at 1273 K strongly suggested three dimensional oxide-ion diffusion.

This paper proposes a thermal design procedure for micro- and nanosatellites that can be completed in one year. Two thermal design concepts keep components within their design temperature range, reducing the temperature change by using the whole structure for heat storage and reducing the temperature change of the inner structure where the most temperature-sensitive components are mounted. One- and two-nodal analysis methods are used for the former and latter concepts, respectively, to clarify the combinations of optical properties for the structures and components to keep within the design temperature range of the components. Finally, multinodal analysis is performed for detail design based on the optical properties clarified from the one- and two-nodal analyses. This thermal design procedure was applied to the Hodoyoshi-1 satellite, which is a cube about 50cm on a side, has two inner plates and has solar cells on the body, is on a sun-synchronous orbit at an altitude of about 500km, and is pointing to Earth. The thermal design of the Hodoyoshi-1 satellite was completed in about 10 months.

We have fabricated composite electrode materials consisting of manganese-molybdenum mixed oxide and carbon nanotubes (CNTs) for supercapacitor application. The process involves electrophoretic deposition (EPD) of multi-walled CNTs onto an ITO electrode, followed by anodic deposition of Mn-Mo oxide from an aqueous Mn(II) solution containing MoO4 2− anions. Electrochemical properties of the composite electrodes with various combinations of Mn-Mo oxide and CNTs were evaluated systematically with the aim of maximizing the electrochemical utilization of the oxide. Optimization led to a high specific capacitance of 408 F g−1 at a scan rate of 2 mV s−1, with an area-normalized capacitance of 31 mF cm−2 (or a volume-normalized capacitance of 76 F cm−3).

Various metal ions (Na+, Ca2+, Co2+, Ni2+, and Pb2+) were intercalated between the manganese oxide layers grown anodically on a Pt substrate. The films were subjected to a repetitive charge-discharge cycle test in an aqueous electrolyte of Na2SO4 between 0 and +0.8 V (vs Ag/AgCl). When the number of cycles increased, remarkably increased capacitances due to pseudocapacitance were observed for the manganese oxide films intercalated with Co2+, Ni2+, and Pb2+, accompanying drastic morphology changes where the multilayers lying parallel to the substrate before cycling were aligned vertically.

Electrodeposition of the layered manganese oxide was conducted in a colloidal crystal template formed by self-assembly of polystyrene particles on an indium tin oxide substrate. The resulting macroporous film exhibited good pseudocapacitive behavior in neutral electrolyte, as a result of contributions of the surface of macropores and the interlayer space of the multilayered structure. Keywords: Template, Electrodeposition, Layered manganese oxide, Supercapacitor

Anodic electrodeposition of layered manganese oxides has been carried out in a MnSO 4 solution heated at various bath temperatures from 25 to 80°C. The crystallinity of the deposits increased with an increase in the bath temperature. Although Co 2+ ions were not involved in the deposition reaction at room temperature, at the elevated temperature the addition of Co 2+ gave rise to a catalytic current suggesting the formation of Co/Mn mixed oxide. No new X-ray diffraction peaks appeared with the insertion of Co 2+ ions in the structure, but their addition caused broadening of the peaks due to the Mn dioxide phase. This indicates that Co ions are not accommodated in the interlayer space but are well dispersed within the MnO 2 layers composed of edge-shared Mn0 6 octahedra. The Co-doped Mn oxide film thus obtained exhibited much better pseudocapacitive performance than the undoped counterpart.

Co 2+ ions were incorporated into the interlayer space of a layered manganese oxide film grown anodically. The film on Pt substrate was subjected to repetitive electrochemical cycling in aqueous Na 2 SO 4 electrolyte in the potential region between 0 and +0.8 V (vs Ag/AgCl). With increasing cycle number, the voltammetric capacitance gradually increased, accompanying a drastic morphological transformation in which the multilayers lying parallel to the substrate before cycling were aligned vertically. The resulting film exhibited a high specific capacitance of 223 F/g at 2 mV/s with excellent charge/discharge stability.