In this study, we have evaluated a nano-emulsion generating device which consists of a piezoelectric element, a vibration plate and a microchannel plate. To estimate the dependency of the pre-emulsion state for the distribution of droplets' diameter after the nano-emulsion state, the nano-emulsion has been generated by an ultrasonic vibration device. When the Y-type microchannel was used for the generation of the pre-emulsion, the obtained droplets' diameter after the ultrasonic vibration process was smaller and had narrow deviation than that by using T-type microchannel.

In this paper, we report on a novel liquid cell unit for energy harvester device that is composed of a PDMS (polydimethylsiloxane) micro chamber, a metal electrode, and an electret plate. The fixed-charges in the electret are formed and polarized by K⁺-doping into a silicon oxide layer that generates power due to the variation of the dielectric constant on the air-liquid interface in the micro fluidic chambers. We foresee the heartbeat as an external vibrational source to pump the fluids in liquid cell units. Electrical currents can be generated to charge small implantable medical electronics such as diaphragm pace maker for amyotrophic lateral sclerosis.

The development of optical motor using light radiation pressure as a power source of MEMS is reported in this paper. The light radiation pressure is a force generated by changing the momentum of light. This force has recently been applied to the industry as laser trapping technology and so on. The applicability in MEMS for the purpose of more actively using light radiation pressure is discussed by developing a novel driving source using a micro-rotor. The torque that can be produced from one rotor using the light radiation pressure is investigated under the dynamics of the optical motor by using experimental and simulation results. It is confirmed that the torque produced by light radiation pressure can drive a micro-rotor. A method of improving rotation speed is proposed. In addition, the promotion of the use of 3D printers in the MEMS field is performed.

In this study, we fabricated and characterised a prototype dual atomic force microscopic cantilever with a large deflectable structure using an Fe₆₅Pd₃₅ magneto-strictive film for cantilever switching. A zigzag-shaped 5-µm-thick liquid delivering cantilever was designed to reduce its stiffness. Moreover, multiple Fe₆₅Pd₃₅ (2 µm) with Si (5 µm) beams were placed on its both sides to generate large cantilever deflections. The imaging cantilever (Fe₆₅Pd₃₅ 2 µm / Si 2 µm thick, 170 µm long) and the hollow cantilever (5 µm thick) were deflected above 1 and 2 µm, respectively, by applying 300 G magnetic flux along the longitudinal direction of the cantilever. In addition, the resonance frequencies of the imaging and hollow cantilevers were 89.2 and 65.2 kHz, respectively. The delivering cantilever showed no resonant peak when the imaging cantilever was resonating at approximately 89 kHz. Furthermore, the vibration amplitude of the delivering cantilever was within 300-500 nm when it was resonating at its resonant frequency, which was sufficiently small to avoid the contact of the cantilever tip with the sample surface as it was being deflected away from the surface by magneto-striction.

Real time measurement of soil pH is demanded in precision agriculture. Therefore, pH measurement capability in low water content soil was needed to confirm. In this paper, we fabricated an ISFET type pH sensor which can be inserted into soil. The sensor performed to measure two type of experiments. First, we experimented with changes in sensor output due to soil water content. The sensor output voltages were changed by changes in the soil pH value. In contrast, the voltages didn't be changed by changes in the soil water content. Secondly, we experimented whether the output of the sensor shows the same change when the soil pH changes during the measurement. The sensor could detect the pH value of soil which was changed dramatically by passing water. We confirmed that the ISFET type pH sensor can directly measure soil pH in real time.

We proposed a novel technique for ripeness evaluation of post harvest fruits using plant bioelectric potential response which has been reported about a relationship with ambient environment conditions and physiological activities of plant. It is widely known that the ripeness of climacteric fruits improves after harvest. In this paper, we measured the bioelectric potential of climacteric fruits (pumpkins and apples) with the elapse of the days for evaluating the ripening stage of fruits. The results indicated that the bioelectric potential measurement has a possibility to evaluate the fruit ripeness.

To make high-selective and sensitive gas sensors, embedding zeolite particle to MEMS structures is studied. However, if the zeolite is aggregated, the zeolite structures become fragile and fall off from large MEMS structures. In this paper, we propose covering the aggregated zeolite particle embedded in micro-trenches with thin crystalline zeolite films. This integration method can be used for other powder form materials, like MOFs and quantum dots. In addition, we investigate the impact effects to the three kinds of zeolites (FAU, LTL, and MFI) with and without the thin zeolite films.

This paper describes a microfluidic device for observation of cancer cell invasion induced by chemotaxis. The developed device has two main-channels, the channel filled with cell suspension and the channel filled with solution containing chemotactic factor. These channels are connected via tapered orifice structures to capture multiple cancer cells in it to form cell clusters. Observation of cell invasions affected by cell adhesions is possible with this device. The devices were fabricated by using three-dimensional lithography and PDMS(polydimethylsiloxane) molding. Invasion cells leaving the cell clusters and moving to the channel containing chemotactic factors through the orifices were successfully observed on the device.

Influence of formation of silica agglomerates on a ultra-thin fluororesin electret on the characteristics of the charge-retention and the aero-ultrasonic sensor was investigated. The ultra-thin PTFE layer (thickness was 2.8 µm) was obtained by spin-coating and silica agglomerates were formed by spraying droplets of colloidal silica. The formation of PTFE/silica agglomerate composite layer on PTFE layer resulted the larger and more flat agglomerates than the formation of single layer of silica agglomerates on the PTFE layer. The measurement of the charge retention of the obtained electrets after 24 h at RT and at 250℃ revealed that the formation of PTFE/silica-agglomerate composite layer on the ultra-thin PTFE layer enhanced the charge retention. Furthermore, the electret condenser sensor (ECS) fabricated using the silica-agglomerate electret on the ultra-thin PTFE layer exhibited the excellent sensitivity and high resonance frequency compared with conventional ECS with PFA layer (thickness was 12.5 µm).