In this paper, we consider an optimum parameter of MPPT unit in the simple configuration of PV generation system by simulation. First, from the stabilization characteristics for MPPT operation of MPPT Converter unit (MC) and PCS, and we investigate the optimum parameter from MPPT operation. Next, we conducted a demonstration experiment using the parameters we obtained and confirmed their effectiveness. As a result, it is confirmed to increase the efficiency of operation of both MPPTs because of setting the P&O parameter of MC higher than that of the PCS. In addition, it is clarified that it is desirable to set the P&O parameter of MC 3 times or more that of the PCS under this simulation condition.

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Carbon nanotube (CNT) dispersion was formed by the in-liquid plasma method. The CNTs were stably and uniformly dispersed in water by this method. The CNT dispersion and the PTFE dispersion were mixed. Use of CNT dispersion is a key process to form the CNT/PTFE dispersion with stability. The CNT/PTFE dispersion was applied to glass substrate to form the CNT/PTFE composite film. The composite films showed electrical conduction. The electrical conductivity was drastically increased by 6 orders with an increase at low range of the CNT concentration between 0.1 and 1 [%] in the composite film. On the other hand, the electrical conductivity was gradually increased by 2.5 times with an increase at high range between 10 and 100 [%]. The computer simulation was also carried out to reveal the conduction mechanism in the CNT/PTFE composite films.

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In recent years, global warming issues due to the increase in carbon dioxide (CO₂) concentration triggered by use of fossil fuels have become even more serious. Therefore, methanation of CO₂ has been considered, e.g. by Sabatier reaction. This reaction requires catalysts such as Ni, and development of catalysts capable of producing methane with high efficiency is required. In our previous studies, it has been reported that methanation is possible by ball-milling of LaNi5 under CO₂ + H₂ atmosphere. Furthermore, ball-milling resulted in a complex structure of Ni / La oxide and carbonates on a nanoscale, suggesting high catalytic activity at the metal/oxide interface. This suggests that ball-milling is effective in catalyst production. In this study, we attempted to prepare a composite powder in which Ni is supported on CaO, which is an inexpensive and easily-reacting oxide with CO₂, and investigated its potential as a CO₂ methanation catalyst. Our results revealed that the methanation of CO₂ occurs with using Ni/CaO composite, while even higher catalytic activity was observed in case of Ni/CaCO₃ composite.

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Due to the recent influence of the new coronavirus (SARS-CoV-2), opportunities to improve knowledge of new medical technologies are lacking. To provide safe medical technology, we examined the medical device operation support system using smart glasses, which is a wearable device. This system enables actual operation while watching operation videos of various devices when necessary and can also provide remote technical support. By comparing the performance of multiple smart glasses, we arrived at an appropriate system that can be used in clinical practice.

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We have focused on the problem that quantitative research on the timbre of musical instruments has not yet been established. In order to solve this problem, we have conducted research on quantitative evaluation of timbre using guitars, which are plucked string instrument among musical instruments. In the previous paper, we proposed a new factor called the octave factor to quantitatively evaluate tone quality. This octave factor was able to show the superiority of two types of guitars, a high-quality handmade guitar and a mass-produced guitar, and was effective for a simple evaluation of the quality of guitar tone. However, if we want to evaluate the quality of tone more strictly, it is necessary to consider the components of consonant interval and dissonant interval. Therefore, this paper incorporates music theory and proposes a new factor called the consonant interval factor. As a result, we believe that the consonant interval factor can quantitatively evaluate the quality of guitar tone more strictly than the octave factor proposed in the previous paper.

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The number of hyperuricemia patients has been increasing. It is important that keep normal uric acid (UA) levels to prevent complicating disease of hyperuricemia. The current standard of UA tests uses a blood sample. However, it is not suitable for self-monitoring of UA level because it involves the burden of puncture and the risk of infection by taking a blood sample. Personal UA sensor is expected to monitor diurnal variation without invasiveness in a casual manner. In this study, we fabricated and evaluated a uricase-based biosensor toward the non-invasive continuous measurement of salivary UA concentration in the oral cavity. Uricase catalyzed UA and produced H₂O₂ in an enzyme-immobilized membrane on a Pt electrode. Then, generated H₂O₂ concentration which is correlated to the UA concentration was measured by the chronoamperometry technique. As a result, not only a wide dynamic range (0.1–10 μmol/L) but also high selectivity for UA was observed. In the future, the developed UA biosensor would allow monitoring UA levels non-invasively and continuously.

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