The necessity for the development of micro power supply technologies for mobile phones and portable electronics has increased in recent years. Methods of self power generation using the vibration loads of structures have attracted attention as the power supply technologies. In this study, we focused on lead zirconate titanate (Pb(Zr,Ti)O3, PZT) as the generating piezoelectric element. The purpose of the study is to develop a high- efficiency PZT generator element that utilizes the vibration loads in the support members of a structure. We report an experiment using La-doped and laminated PZT elements to drive a wireless accelerometer. The wireless accelerometer device was composed of capacitor, switching circuit, voltage sensor and accelerometer module. The charges generated from La-doped and laminated PZT element are charged by the capacitor, and it reaches to the wireless accelerometer through the switching circuit. As a result, it is possible to obtain the acceleration information. Based on these results, we confirmed driving the wireless accelerometer using La-doped and laminated PZT elements.
This paper proposes a method to detect the center of gravity position of an object in a short time. The method may be used for real-time detection of the center of gravity position for a walking robot, a running vehicle, etc. The detection circuit employs some neural comparators based on the behavior of information processing of a biological neuron. The circuit calculates the ratio of the two signals generated from load cell sensors, and detects the center of the gravity position between the load cell sensors located at the both end of a beam. The detection error of the location is within about 3% at full-scale ratio form the circuit experiments. The detection time is about 200ns from the input signal of sensors until the output of the detection signal on average. A parallel processing circuit using a layer of neural comparators enables fast detection.
A thin-film magnetic field sensor is useful for detecting foreign matters and nanoparticles included in industrial and medical products. It can detect a small piece of tool steel chipping or breakage inside the products nondestructively. An inspection of all items in the manufacturing process is desirable for the smart manufacturing system. A previous study proposed a sensing system in which a thin-film magneto-impedance sensor was set in a strong normal magnetic field and detected the foreign matters at the same time as magnetization. In this paper, an impedance property of a thin-film magneto-impedance sensor and magnetic domain of it is investigated within up to 0.35 T normal magnetic fields against substrate plane for the purpose of improving performances of the proposed sensing system. A verification of sensitivity of the sensor was also carried out subjecting to 0.3 T normal magnetic fields.
In this paper, we developed a quartz oscillator based liquid concentration sensor that analyzes ion species and concentration in a conductive aqueous solution using external magnetic field and frequency dependence. This sensor is composed of the sensing capacitor (SC) and quartz crystal resonator (QCR). The proposed sensor is a contactless capacitive sensor using out-of-plane electric field of a planer sensing capacitor. We succeeded in improving sensitivity using frequency dependence and estimating ion species in aqueous solution by applying an external magnetic field. Because this contactless capacitive sensor is low-priced, we can expect the use for the liquid management of various fields.
Intravascular treatment using catheter, such as coil embolization, flow diverter stent placement and removal of clots, is a less invasive treatment for vascular disease than conventional surgery procedure. Recently, intravascular treatment has been used increasingly because it is useful to reduce patient's burden compared with conventional craniotomy procedure. In this research, cerebral blood vessel models with micro sensors such as ultrasound displacement sensors and fiber-optic pressure sensors are fabricated. It is expected that a blood vessel model with micro sensors is useful to evaluate skillfulness of doctor's technique of intravascular procedure and effectiveness of training. And this model can be used for new medical device developments to evaluate these safety and efficacy. 3D printing system of vessel model has been developed and placement of sensors during the printing procedure is proposed.
In this paper, Ga2O3/Se heterojunction photodiodes at a thickness of less than 1 µm are patterned on a transparent polyimide film. Photodiode patterns enabled simultaneous and multi detection of light intensity. Tiny, light- weight, and flexible features of the developed sensors are also attractive for practical applications such as sensors for wearable and/or robotics systems. Above-mentioned sensors can be attached onto even non-flat surfaces of human finger and/or movable parts of robotic systems. The details of film growth processes and patterning of Ga2O3/Se photodiodes on a polyimide film are also discussed.
In this study, the transparency of SiCO thin films for optical waveguides was improved by a reactive sputtering method with O2 as the reactive gas. Ten samples with different oxygen inflow ratios (fo) were prepared. As fo increased, the following effects were observed: an increase in O2, a decrease in the absorption coefficient, a widening of the optical gap, the relaxation of the internal stress, a reduction in the refractive index, and a reduction of the mechanical strength (hardness and young's modulus). It was found that these dependencies were stronger when fo ≤ 10%. Where fo = 7%, the thin film had a relatively high mechanical strength, refractive index, and optical gap (1.80 eV). In this case, the excellent optical and mechanical properties make the thin film suitable for an optical waveguide.
In this paper, an optical pressure-sensitive membrane based on plasmon resonance absorption has been designed, fabricated, and demonstrated. The membrane utilizes plasmon resonance on a gold island film embedded in a polydimethylsiloxane (PDMS) layers, and the shift of the resonant wavelength was used as an indicator of pressure-induced strain of the membrane. The membrane with total thickness of 100 µm were prepared with spin-coating of PDMS and vacuum evaporation of gold island film with the nominal thickness of 10 nm. Pressure sensitivity of the fabricated membrane was demonstrated from the measurement of absorbance spectra and the maximum sensitivity of 0.35 nm/kPa was achieved by applying pressure up to 35 kPa. Plasmon resonance mode attributing to the pressure sensitivity has been analyzed through comparison between electromagnetic simulation and membrane stretching test. From the stretching test, red shifts of the resonant wavelength were obtained for both parallel and perpendicular polarizations to the tensile direction with the sensitivities of 0.372 and 0.134 nm/%, respectively. From the electromagnetic simulation, these red shifts can be attributed to both gap-mode and deformation-mode resonances of the gold island film.
A rapid and easy viability assay of budding yeast cells using the electro-orientation (EO) phenomenon in an AC electric field was developed without any reagents. Saccharomyces cerevisiae cell suspension was simply sandwiched between two indium-tin-oxide plate electrodes. The EO directions of each cell indicated whether the cells were alive or dead at a narrow frequency band of 10-20 MHz. By observing through the transparent electrodes, the living cells were appeared as perfect circule shape when oriented parallel to the electric field line, while the dead cells were appeared as snowman and egg shapes when oriented perpendicular to the field.
In this study, the plasmonic membrane which constructed with the noble metal nanostrcutres on the membrane filter was fabricated for localized surface plasmon resonance (LSPR)-based sensor applications. This plasmonic membrane can be fabricated rapidly and due to the deposition of the noble metal layer onto the membrane filter. This plasmonic membrane exhibit the specific optical characteristics by the LSPR. And the LSPR absorbance peak wavelength change could be observed which depends on the thickness of the noble metal layer. Based on these LSPR characteristics of the plasmonic membrane, evaluation of sensing performance with different surrounding refractive index was carried out.