In this study, a relay resonance circuit is used transmitted power to the sensor module using four-parallel cubic coils, and the efficiency decrease with the change in the transmission distance is investigated experimentally. The relay resonant circuit used was examined for resonant frequencies that were near the usable frequency. A square coil was used as the receiving coil. Using Vector Network Analyzer (VNA), the S-parameters were measured with the transmitting and receiving coils as 2 ports, and after converting the S-parameters to Z-parameters, the theoretical maximum efficiency η_max was calculated. The distance variation characteristics using each relay resonance circuit were investigated. As a result, it was found that the theoretical maximum efficiency was improved when relay coils were used, and that the theoretical maximum efficiency tended to increase when the resonance frequency was slightly larger than the frequency of the power supply circuit.

We investigated a measurement method using a dual source bridge type high-precision high-resistance measuring instrument ranging from 10MΩ to 10TΩ. All possible uncertainty components of the instrument were evaluated and its measurement uncertainty for each resistance range was estimated and the details are argued in the manuscript. We performed the verification of the instrument by performing a precise comparison with the national high-resistance bridge maintained by NMIJ/AIST, and it showed good agreement with its uncertainty.

We are developing a user-friendly tabletop NMR (Nuclear Magnetic Resonance) quantum computer for student labs. This device enables the observation of quantum behaviors of atomic nuclei and aims to demonstrate quantum algorithms for students. Successfully executing quantum algorithms requires enhancing the signal-to-noise ratio (S/N). One approach involves extending accumulation times. However, the magnetic field generated by a pair of Ferrite magnets in this device is temperature-sensitive; even minor room temperature changes cause data accumulation failure. To tackle this problem, we devised a program capable of accumulating data while monitoring temperature changes by observing NMR signals themselves. This approach allowed us to conduct lengthier accumulations and effectively implement quantum algorithms. This paper presents advancements achieved by utilizing temperature monitoring to enhance the S/N and successfully implement quantum algorithms. We also show a possible syllabus for conducting quantum computing experiments for undergraduate students.

The investigation of voids in concrete slabs is a crucial aspect of concrete diagnostics. We have reported that it is possible to efficiently detect the presence of voids by identifying the scattered waveform through an artificial neural network (ANN). This study serves as a sequel, aiming not only to determine the presence of a void but also to detect its location and thickness. The ANN-based estimation demonstrated good accuracy even when the observed data included some noise or when dealing with models featuring weak conductivity. Additionally, a substantial amount of scattered waveform data is required to train and test the ANN. In this research, we leverage frequency domain analysis and FFT techniques to create the scattered waveform data of a concrete slab considered as a flat layered medium. This approach allows for significant time savings in computation compared to the finite difference time domain (FDTD) method used in our previous studies.

We investigated equivalent radii of penetration holes in insulating films in order to clarify that discharge diameter and gas temperature distribution shape of impulse arc discharge during penetrating insulating films. We fixed five insulating films between high voltage electrode and ground electrode, and calculated equivalent radii using penetration holes of insulating films with different melting points. As a result, it was found that from relationship between melting point and equivalent radius, temperature distribution shape of impulse arc discharge during penetration of insulating film was a convex shape with high temperature at the center and flat temperature at the outer peripheral part.

It has been required to develop simulation of vacuum arcs as a tool to aid electrode design in vacuum circuit breakers. Although the development of electromagnetic thermo-fluid simulations for vacuum arcs has been reported, most of them do not take cathode sheath phenomena into account and have not been able to reproduce vacuum arc phenomena, especially cathode spots. As the first step, the cathode sheath voltage, cathode surface electric field, and temperature and field (T-F) electron emission current were analyzed numerically on the basis of the space charge in the cathode sheath. In this paper, the cathode sheath was assumed to exist when the charge density induced on the cathode surface is positive, and the temperature and density of vacuum arc plasma and cathode temperature, which are physical quantities obtained by electromagnetic thermo-fluid simulation, were used as parameters of the analysis. As a result, the cathode sheath voltage, electric field, and electron emission current density can be calculated from the vacuum arc plasma temperature, density, and cathode temperature. Numerical results show that the electron emission current density has a dominant effect on the presence or absence of the cathode sheath.

This paper describes the results of probe diagnostics in atmospheric pressure argon plasma jets (APJs) for the clarification of their internal structure. The probe is consisted with a fine stainless-steel wire and a resistor. Observed probe current waveforms contain both of displacement and conduction currents, thus they are separated into two components. As the probe position moved away from the nozzle, the remarkable variations in waveforms were found that the amplitude of the former decreased, whereas that of the latter increased. Hence, we called them as “active region” of APJs and investigated their behavior. From the results, we recognized the existence of the active region positioned at the downstream from the brilliant region in the APJs as the natural character without the probe insertion.

The electrospray deposition (ESD) method is wet process used solution spray formed by electric field between the needle of solution contained syringe and conductive substrate or insulated electrode. In this study, we fabricated thin films based on 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene) formed by a new direct pattening ESD method. This method is an electric field applied between the nozzle and patterned electrodes on the substrate. It enables to form patterned films on such as plastic films. Moreover, this ESD method allows controlling patterned film width by using voltage on counter patterned electrode. These results demonstrate that the patterned TIPS-pentacene film width by controlling voltage. We fabricated flexible OFET using this method and measured static electrical characteristics.

Sulfur hexafluoride (SF₆) is a powerful insulating gas, yet its global warming potential (GWP) of 25,200 compels us to urgently seek eco-friendly alternatives. Various experiments and computations have been conducted to develop SF₆ alternatives that fulfill requirements for dielectric breakdown strength, GWP, and boiling point. However, the efforts has been hindered by limited experimental results as well as inadequate computational performance to extrapolatively predict gas properties of unknown molecular structures. Thus, this study conducts high-throughput screening of gaseous molecule space using quantum mechanics-assisted machine learning model. This exploration has expanded the existing small-molecule space to encompass 3 × 10⁸ molecules, a 1500-fold increase over databases, equivalent to registration efforts spanning 4.5 × 10⁴ years. The computational results identify potential candidates that pose high breakdown strength at low-temperature and high-pressure conditions while maintaining low GWP. These findings lead to crucial insights into the next steps of computational design and experimental verification for SF₆ alternatives.