An algorithm that constructs a nonlinear map from a high-dimensional feature space into a low-dimensional space was developed to enable analysis of the structure of data with high-dimensional characteristic features and their class information obtained using various sensors and analyzers. First, a nonlinear map is defined by summing nonlinear basis functions, and their optimal combination is derived using a genetic algorithm to avoid the “curse of dimensionality.” Next, the coefficients of the basis functions are derived using the Nelder-Mead method to flexibly cope with the various demands for the map that cannot always be expressed using statistics of the characteristic features. As a result, nine-dimensional sake data can be mapped into a two-dimensional space so as not only to discriminate the classes but also to preserve the order of distances between classes as much as possible.
This paper addresses the error-matrix method applying to the prediction of the off-design operation for a microscale gas turbine engine. Aerodynamic design of rotating components was carried out to obtain the performance maps which can be used for the off-design operation. The performance maps for the compressor and turbine were obtained from the CFD analysis with the mass flow rate average technique.
In this paper, flow visualization of the oblique shock waves of a single-crystal-silicon microscale supersonic wind tunnel is described. The microscale supersonic wind tunnel has a convergent - divergent section and a throat area of 1000µm×300µm, and designed for realizing supersonic flow of Mach 2 in microscale domain. The schlieren system with integrated optical microscope was used for visualization of the oblique shock waves generated in the microscale domain. To investigate the effect of nonisentropic flow state on the inclination angle to the shock, a numerical integration of the modified Shapiro's differential equation was applied.
We fabricated a strain sensor using the inverse-magnetostrictive effect of magnetoelastic thin films, and applied it for vibration sensor. The sensor element consisted of 1 turn meander-patterned molybdenum (Mo) film as conductive layer and FeSiB magnetostrictive films that laminated a part of the meander. After annealing the element, the FeSiB films of the sensor element were subject to residual stress from Mo film and Si substrate, which induced a magnetic anisotropy of the FeSiB film via magnetoelastic coupling. From the impedance change of the element under compressive strain the sensor exhibited a gauge factor of 2,160 at a carrier frequency of 150MHz under compressive strain. In addition, a phase-difference detection circuit was fabricated to evaluate the element as a vibration sensor. When an edge load of 20g was attached to the element, the maximum signal of 288mV (45mV/deg.) correspond to vibration was obtained at the mechanical resonance frequency of 20.8Hz.
The redox sensor is a type of electrochemical sensors that can detect chemical substances from redox response derived from the characteristics of the substance. Redox sensor is attractive due to their fast response, sensitivity, simplicity and miniaturization. Therefore, redox sensor is expected to be applied to onsite monitoring. However, the redox output current is reduced if the sensing area is small and/or the concentration of the sample is low. We proposed an amplified redox sensor (ARS), which combines the sensing area that serves as a working electrode with a bipolar transistor. For onsite detection, portable small size device that can measure even small concentrations is required. In this paper, we report the performance limit of our proposed ARS from input referred current noise that we calculated from measurement conditions of cyclic voltammetry and square wave voltammetry using potassium ferricyanide. In addition, we compared to MOSFET based transimpedance amplifier of a single element. As a result, bipolar transistor based the ARS can expect low detection limit about 2 orders of magnitude lower. Hence, we believe that the proposed amplified redox sensor devices can be used in high sensitivity on-site monitoring in electrochemical measurements.
This paper presents system design and construction of an ingestible core body thermometer based on the generation of gastric acid power for daily monitoring of basal body temperature during sleep. A custom integrated circuit (IC) with voltage boosting, coding, modulating, and transmitting functions was prototyped. A chip-shaped gastric acid battery based on a pair of Mg and Pt thin-film electrodes was fabricated using microfabrication technology. Charge storage in a multilayer ceramic capacitor at a boosted voltage was demonstrated with the battery and boost circuit in the IC. An evaluation board of the system was also prepared. The essential electrical components were mounted on 3-pieces print circuit board with the diameter of approximately 10 mm, which suggested the possibility of miniaturizing this system to the size of a tablet. The magnetic-field coupling telecommunication of data between a small transmission coil and a loop antenna, as a receiver, was successfully demonstrated. The energy consumption for temperature measurement and transmission was low enough for multiple measurements during sleep. These results proved the feasibility of an ingestible thermometer system.