We propose a triaxial gyroscope with a mounting structure composed of four non-rectangular building blocks with an inclined face on which a single-axis gyroscope is mounted. The mounting structure is designed considering high inter-axial orthogonality, stress resistance, and redundancy for three-axis angular rate detection in the event of failure. Injection molding and molded interconnected device technologies are used to produce plastic blocks with highly precise faces (face angle error: ±0.05°). A prototype is fabricated using blocks in which a Z-axis gyroscope is incorporated. The blocks are accurately positioned by pressing against an alignment jig. Three-axis test results obtained via a vector operation on the outputs of four Z-axis gyroscopes demonstrate a sensitivity to the applied angular rate of 100% for the main axis and ±0.2% for the other axes. An inter-axial orthogonality error of below 0.1° is also demonstrated. The proposed gyroscope detects the three-axis angular rates with low cross-axis sensitivity and has high inter-axial orthogonality.

In this study, we developed a corrosion reaction monitoring system using an electrode-separated quartz crystal mass sensor to enable wireless monitoring of corrosion reactions in isolated spaces without the need for direct wiring. We evaluated the effects of changing the material and thickness of the window material and subsequently tested the system in an enclosed environment to assess both its performance as a mass sensor and its response as a corrosion sensor.

To expand the application of wireless sensor nodes using energy harvesting, an energy management circuit that combines energy harvesting from indoor light and waste heat is proposed. The circuit is composed of an analog LSI circuit and achieves energy management with a power consumption of 1 µW. The circuit has been demonstrated to generate 120 µW of power using waste heat with a temperature difference of 5°C in a low-light environment of approximately 50 lx.

This paper proposes a silicon resonant type ceramic pressure sensor with a minimal effect of ambient temperature. A static force driven silicon resonant sensor chip, which enables high accuracy, excellent repeatability, and long-term stability, is directly bonded on a silicon nitride (Si₃N₄) diaphragm by surface activated bonding. To minimize the thermal strain induced by the difference of coefficient of thermal expansion between silicon and Si₃N₄, a temperature compensation was achieved by designing a round-shape bonding area on the chip and by tuning thickness ratio of the chip and the diaphragm. As a result, it is confirmed that the thermal strain of the silicon resonator (-0.013 µε/°C) was much smaller than the pressure strain (46 µε/MPa), which corresponds to simulation results.

In this paper, we propose a new evaluation method for the spatial distribution of sensitivity to force in a cantilever-type MEMS tactile sensor developed in our laboratory. By combining the responses of two strain gauges attached to the cantilever with different coefficients, it is shown that the spatial distribution of sensitivity can be controlled and the force application position and the magnitude of force can be predicted with high accuracy.

In this study, we developed a double-sided offset ring-electrode nanopore device and a prototype hand-held measurement system, and evaluated the overall performance for the application of AI-driven AC nanopore method to microbial phenotypic sensing. First, the particle measurement performance was evaluated and found that the sensitivity was approximately three times higher than that of conventional systems for particles up to 120 nm in diameter. n microbial identification using a single nanopore device, the accuracy of classification of 16 types of bacteria and 11 types of viruses using a convolutional neural network was approximately 83% and 78%, respectively. This suggests the possibility of classifying both bacteria and viruses with a single nanopore diameter. Furthermore, the method achieved 94.5% accuracy in three basic classification tasks of conventional colony counting method, demonstrating that this method is upward compatible with colony counting methods.

This paper proposes a precise deposition of Te adhesion layer for improving device performance of Se thin film based photovoltaic devices. The aim is to enhance the adhesion between the TiO₂ (or ZnMgO) and Se layers while limiting the detrimental effects of excessive Te layer which causes unfavorable leakage at pn junction, resulting in an obvious improvement of the power conversion efficiency of Se heterojunction photovoltaic devices. A reproducible deposition technique at slower deposition rate (∼0.5 Å/s) is proposed by controlling the crucible temperature during tellurium deposition. TiO₂/Se photovoltaic device improved the photovoltaic conversion efficiency from 2.37% to 3.52% under light illumination at AM1.5, 100 mW/cm² (1 sun calibrated with a solar simulator) by decreasing Te film thickness from 5 nm to 1 nm. It is considered that the increased open circuit voltage from 0.529 V to 0.687 V, attributed to the decreased dark leakage current at pn junction by decreasing Te layer thickness 5 nm to 1 nm. Almost three folds of power conversion efficiency was obtained under indoor LED illumination as compared to that under 1 sun light illumination because of the optimum bandgap energy of Se to indoor light spectrum.

In this study, we developed an in-situ measurement technique for the temperature coefficient of resistance (TCR) of Pt thin film. Pt thin film was exposed to high temperature in the electric furnace at 400°C to evaluate the sintering time dependence of TCR and specific resistance of Pt. During the long-term sintering of Pt thin films at 400°C, it was confirmed that the TCR of the Pt thin films gradually increased, while the specific resistance gradually decreased. Since the specific resistance of the Pt thin film almost linearly decreased with the increase in TCR, TCR can be deduced by measuring the resistance of the Pt thin film. By using the deduced TCR value, it becomes possible to accurately measure the temperature of the micro-hotplate, thereby maintaining the accuracy of the thermal conductivity gas sensor over a long period.