Conventional vibration generators have used simple pendulums. Their maximum generating power was less than several 10 mW. When a rotating body is given a pitching vibration, a gyro effect is caused and a large torque is obtained. The gyro generators use this effect and generate more than 1W. There are 2 types of gyro generators. The one spins a rotor by a motor and the other by a precession friction force. The motor driven type has an advantage oft working under arbitrary vibrations. The friction driven type has an advantage of a simple structure. This paper explains principles of gyro generators and our related research.

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This article presents a brief introduction to the dynamics, design, and power optimization of electromagnetic vibration energy harvesters (VEHs), and explains how the power-bandwidth tradeoff of the VEH can be resolved by introducing mechanical nonlinearity, which enables the VEH to be wideband while maintaining its maximum power performance. The well-recognized difficulty of coexisting solution is then described, and the response stabilization control technique proposed by the author is presented as the promising solution of this issue.

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Potassium ion electret technique was invented in 2012 and first reported in IIP2012. This technique is able to give a semi-permanent high bias voltage to silicon MEMS devices having high aspect ratio structures. Potassium ions are introduced by thermal oxidation process, and then evacuated from the oxide by applying a voltage with heating the device at about 550 degree. Consequently, remaining negatively charged oxide defects compose a space charge region in the oxide and make a electret potential. This technique has been applied to vibration energy harvesters made of a silicon wafer and showed ability of power generation with very low acceleration and wide-band frequency response.

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Human sensing technology is used in various fields such as medical field and industrial field. In this human sensing, motion information such as the position of each part of the body, physiological information such as heartbeat, psychological information such as sensation, etc. are measured. In the measurement of biological information with mechanical phenomena, the viewpoint from mechanical engineering is important to consider the selection and arrangement of sensors. We develop the measurement system of finger motion to investigate relationship between the tactile sensation and the finger motion. In this paper, the developed measurement systems are introduced.

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The understanding of microfluidic phenomena is one of the key issues for the development of the printed electronics technology. For example, the contact line pinning of droplets is a critical phenomenon which often prevents accurate, reliable micron-scale pattering of circuits on polymer substrates. Here, we report the observation of water droplets using an environmental scanning electron microscope (ESEM), focusing on the dewetting process, i.e., the contact line motion of evaporating droplets with diame ters less than 100 μm on a parylene-C surface. The ESEM observation reveals how the droplet scale impacts on the pinning of contact lines. The results for the wetting (condensation) process is also presented.

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Pressure- and Temperature-Sensitive Paints (PSP and TSP) is promising measurement technique for thermo-fluid phenomena, because they enable us to non-intrusively measure the pressure/temperature distribution on the surface to which PSP/TSP is applied. The PSP/TSP measurement technique is based on oxygen/thermal quenching of the luminescence of PSP/TSP dyes. For the precise measurement, small change of the luminescent intensity is precisely detected by a photodetector. Then, the application of PSP and TSP is limited to the measurements in aerospace engineering. We have applied PSP to pressure measurements of micro-scale flows and of the rotating disk inside an HDD. The PSP/TSP is usually applied to a model surface by a sprayer (by hand). Recently, we have proposed inkjet-printed PSP and TSP with highly controlled PSP and TSP arrays and high reproducibility.

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It has been reported that various liquids confined in nano gaps has unique mechanical characteristics different from those in the bulk state. Specifically, the mobility of the liquid molecules is lowered due to the intermolecular interaction with the surface, and the non-Newtonian property such as the viscosity increase, solidification, and shear thinning of the liquid occurs in the nano gap, which is known as the nan-confinement effect. As for the nano-confinement effect, no theory has been constructed, prediction of the effect is difficult from macroscopic physical properties, and measurement method is not sufficiently established. This research aims to elucidate the mechanical properties (shear viscoelasticity) of lubricating oil cofined in the nano gap by establishing original measurement method.

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Clinical analyzers which deal with many liquid samples use reusable metal nozzles to suck and dispense samples. These nozzles are cleaned manually every periodic maintenance. To automatize the cleaning of these nozzles, a small ultrasonic cleaner was developed. The ultrasonic cleaner has a L-shape head with a hole in its extremity which is soaked in the cleaning chamber. The nozzle is cleaned by first to dip the tip of the nozzle into the hole, and by then oscillating the L-shape head enough to cavitation occurred around the tip of nozzle. This report presents cleaning performance of the developed small ultrasonic cleaner, as well as the features of the ultrasonic oscillator with L-shape head and the cleaning chamber.

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In recent years, the proportion of elderly people in the population is one of the social problems. Similarly, the workload of care workers is increasing. Actually, the onset of symptoms is remarkable. Especially back pain is a serious problem for care workers. Also, low back pain is mainly caused by transfer assistance and posture change of the elder person. Posture change is a work required for improvement of bedsore caused by pressure and shear force. In other words, make posture change unnecessary by preventing bedsore automatically. Therefore, we focused on measuring system of pressure and shear force. We proposed the mechanism capable of force feedback and measuring shear force. These results are showed that the pressure can be measured. Additionally, these results are suggested that utility.

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10 m fastest gait examination is conducted to investigate the sign of mild cognitive impairment. Inertial sensors composing of accelerometer and gyro sensor are attached on both left and right tiptoes over the shoes. Subjects with age ranges from 19 to 93 were asked to walk at their fastest speed while the inertial sensors measure the acceleration and angular velocity of the toes. Data from men (68.0±10.7 years old, n=634) and women (54.5±8.6 years old, n=856) are used to calculate gait parameters such as stride length, gait rate, gait velocity, toe’s angle, toe’s height, and percentage of swing phase. MMSE (Mini-Mental State Examination) is conducted on all subjects and correlations coefficients R of the MMSE score with parameters including gait parameters are calculated. For men, parameter with highest correlation is age followed by fastest 10 m walking time and walking velocity with value of R is 0.50, 0.38, and 0.38 respectively. For women, parameter with highest correlation is walking time followed by age and walking velocity with value of R is 0.35, 0.35, and 0.34 respectively.

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Currently, the visually impaired find it difficult to use mobility support facilities because they depend on ambient environment such as ambient sound and snow cover. Further, people who acquired visual impairment in the later stages of life also find it difficult to use these facilities. Therefore, in this study, we aimed to develop a walking guidance system using 3D sounds that will not be influenced by the surrounding environment and will be easy to use. Further, we verified the induction effect in the blindfold state and the ambient sound. This system was implemented with a head mount display that is capable of producing 3D sound. Under a visual restriction environment, blindfolded participants were asked to walk toward a real or 3D guiding sound with three types of ambient sounds, and then, we measured the walking locus. We found that the 3D sound tends to provide veering tendency opposite of the ambient sound. However, the guiding accuracy of the 3D sound is similar to that of real sound.

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The research address characterization of setup skill of clinical equipment with considerations of operator’s physio-psychological activities. The focus of this study is to demonstrate physio-psychological indices on the achievement of setting a hemodialysis blood circuit. The circuit is clinically standardized but complex permitting varieties on their degrees of experiences and practices individually. Our measurement system consisted of the electrocardiogram, electrodermal activity (EDA) monitoring on a palm, and synchronized video recording. Thirteen students participated in the experiment, who belong to a clinical engineering course in training for hemodialysis equipment and procedures. Time and frequency domain analysis of the RR intervals by short time Fourier transform (STFT) and Lorentz plot descriptors indicated activities of the sympathetic nerve, and EDA responds implicit emotional arousals during the assembly task. Results suggested a possibility for characterizing the task revealing a sign of attention or confusions on particular events. The proposed approach expects to contribute improvement of an operator's practicing with efficient feedback.

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In this study, a single joint robot finger system to palpate the prostate is developed. For the palpation, the robot finger is bended by pulling the driving wires. And estimation of the robot fingertip position from the length of the driving wires and estimation of the contact force between fingertip and measuring objects are necessary. First, the theoretical model of the robot finger geometrically was constructed, and the relationship between the bending shape and the coordinates of the fingertip was derived. Also, a method to estimate the contact force between the fingertip and the object using the principle of virtual work from the tension of the driving wires was derived. Next, the robot fingertip position accuracy was confirmed by conducting position measurement experiment. Finally, a palpation experiment was conducted on the gel samples, and the utility of this system was confirmed by estimating the contact force.

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In this paper, a palpation sensor system to detect lumps in soft palpation objects such as breast cancer is developed. During scanning of the developed sensor on the measuring objects, the reaction force applied to the contact part is measured by a load cell. And the lump is detected by find a peak waveform of the reaction force. Measuring objects embedding a lump with several conditions of depth and diameter are prepared. Palpation experiments for the measuring objects are conducted. And from the results, it was found the lump of 6mm in diameter embedded in 15mm in depth can be detected with the developed palpation sensor system. In addition, by investigation of relationships between the pressing depth of the sensor to measuring objects and the depth of the detected lump, it was suggested that the depth of lump can be estimated from the combination of results for different pressing depth conditions.

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The viscosity of liquid is one of the important indicator in various fields. Usually, when evaluating the viscosity, it is evaluated as the representative of bulk. There was no method to evaluate the local viscosity evaluation of a specific place, such as near the wall surface or near the gas-liquid interface. In this study, we use the optical tweezers to capture micro-particles and move them in liquid. When the two forces, the trap force of the optical tweezers and the Stoke’s force on the particle are in balance, the local viscosity of the specific place can be evaluated. As a result, we were able to get experimental values that are close to literature values.

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Using colloid probe atomic force microscopy, we realized accurate measurement of squeeze force generated when the probe approaches a sample surface in liquid. This allows us to quantitatively evaluate slip length of liquids on sample surfaces. We demonstrated that, in contrast to the quartz crystal microbalance method, slip length can be measured regardless of the presence or absence of adsorbed films on sample surfaces and regardless of viscoelasticity of adsorbed films. From measurements on adsorbed films with different molecular structures, correlation between slip length and surface energy of adsorbed films was not observed; instead we suggest that slip length is more likely to correlate with adhesive energy between liquids and the underlying surfaces.

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We report on an attempt to investigate electro kinetic behavior of the particles dispersed in colloidal liquid. Colloidal liquids are expected to be potentially useful as thermal transport media such as nanofluids and micro - /nano emulsion. In the present study, we investigate the velocities of colloidal particles influenced by different aspects of electrokinetics. We developed a measurement system for evaluating velocities of colloidal particles in the vicinity of solid glass surface. The measurement principle is based on laser Doppler method using an interference of coherent evanescent lights created at the boundary between solid glass and test colloid. In the present study, we used aqueous solution of polystyrene particles with different diameters filled in a test section. We measured the flow velocities of the particles under different magnitudes of the electric fields induced to the test liquid. The results shows a linear increase of the mobility with the induced strength of the electric field. In the final presentation, we will report on the initial investigation with a temperature controlled test section.

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Molecular analysis of viscosity index improver polymers are investigated by multiphysics simulations. Polymer segment motion is described by Langevin dynamics. Flow of base oil is calculated solving Navier-Stokes equation by lattice Boltzmann method. The force between the polymer segments and solvent base oil is calculated by Stokes force applying on the center of the mass of polymer segments, using the mean velocity from the fluids. In bulk solution under shear, the inversed temperature dependence of the radius of gyration of polymers are found. Under no-shear system, the radius of gyration increases with the polymer weight increases, whereas the reverse dependence is found in the shear case. In confined solution under shear, given by the movement of a solid wall, the polymer molecules moved to the solid wall direction, due to the lift force. This means, not only the inter-molecular force but the hydrodynamic force is important to understand the viscosity improving and adsorption process.

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A new type of sliding probe for clarifying nano-lubrication phenomena was proposed. In the probe, a small glass sphere was attached with a micro structure for lateral force detection, while a quartz oscillator was used for normal force detection. Although feasibility was demonstrated, repeatability and sensitivity of normal force detection were low. In this study, the repeatability and sensitivity were improved.

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Machine miniaturization is remarkable due to recent development of mechanical technology．The influence of capillary force by wet environment is dominant in small machines． For this reason, the influence of the wet phenomenon cannot be ignored in designing of small machines． Therefore, it is important to evaluate the capillary force under humid environment． The capillary force is closely related to the meniscus shape．In this research, in order to record the force under wet environment and the meniscus shape, firstly we developed a device which can precisely observe the wet shape and measure the surface force simultaneously． Subsequently, we report on the relationship between the surface force and the meniscus shape.

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To prevent frost covering on a heat exchanger surface, several micro-meter-sized asperities were built by vinyl chloride dissolved into acetone solution. The building up procedure and cost were much smaller than electron beam drawing or other micro-fabrications. The silicon substrate was chosen as a substrate material, then it was cleaned by ultrasonic cleaning with acetone in 15 minutes. The vinyl chloride dissolved into acetone solution was put on the Si substrate, then it was set in a vacuum chamber. After the evaquation, the sample surface was cleaned by acetone again. The average asperities diameter were approximately 18.6 μm, 9.0 μm height, and 12.7 μm distance between each asperities. The frost observation in the ESEM was conducted. Photographs, illustrations and tables must have captions.

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In this study, I have investigated the dry friction properties of nanostripe structure under a high vacuum condition, (less than 2.0×10^-4 Pa) Nanostripe structure has a multilayer consisting of soft metal of Ag and hard metal of Cr. Unpolished and polished nanostripe structures of Ag and Cr were rubbed with SUJ2 ball. Moreover, unpolished nanostripe structure was rubbed with Al₂O₃ ball under loads of 0.5 N, 3 N, and 6 N. The result showed that friction coefficient for polished nanostripe structures were higher than that of the unpolished one throughout for the friction test. Friction coefficient for unpolished nanostripe structure decreased to 0.15-0.2 after about 3000 oscillations under a load of 6 N. Si plate was rubbed Al₂O₃ ball with transfer particle under a load of 1 N. Friction coefficient of Si plate by transferred Al₂O₃ ball was higher than that of one by new Al₂O₃ ball.

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In an environment, where a human and a robot coexist, it is necessary to control the robot corresponding to the change in the object status by means of tactile sensation. On the other hand, Tacit Learning (TL) is formulated based on creature’s nerve systems to adapt itself to various environments. In this research, our objective is to develop a TL system capable of performing object grasping and tracing motion, which is applied to a 2-linkfingered hand equipped with tactile sensors. Since the output is limited to either positive or negative in the original TL, both positive and negative outputs are required to control the joint of the robot. We assumed two kinds of clusters (artificial neurons’ cluster) specializing in output of positive and negative values, and newly introduced an algorithm for determining which cluster is used according to the positive or negative value of the sensor. In a series of simulation experiments, we conducted two tasks: one of them was tracing a surface of a circular object with one finger; the other was picking up an object with two fingers. Simulated results show that our system can follow a suitable contour of the object and that its grasping force is adequately adapted according to shearing force direction and magnitude.

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Vibration stimulation on an antagonist muscle changes human motion from his/her intended motion. In previous studies, it has been already known that the human motion change can be generated in forearm supination/pronation, elbow joint flexion/extension, and knee joint extension motion. The purpose of this study is to investigate the effect of frequency change to the amount of knee joint extension motion change. The experimental results suggest that the frequency change from 20 to 100 (Hz) affects the amount of knee joint extension motion change.

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We focused on kinesthetic illusion (KI) with the aim of developing simple, compact and inexpensive rehabilitation system. In this research, we aim to forcibly extend the wrist by a motor and clarify the relationship between the extension angle condition and the illusion amount in order to show effectiveness of KI in work therapy. To accomplish the abovementioned objective, a motor was used to extend the right hand and a safety device was designed and developed to limit the motor movement. The amount of illusion was evaluated by analyzing the direction of the illusion, the maximum angle of the illusionary limb, the speed, and the latent time from the trajectory by reproducing the illusion with the left hand’s bend. Comparing the maximum extension angles of the two experiments of discrete and continuous angle changes, it can be seen that the maximum extension angle increases with discrete angle changes at any frequency. Although we cannot conclude superiority of continuous angle change because latency and extension speed were not analyzed in the continuous angle change, both of discrete and continuous changes produced larger maximum extension angle than no-assist cases.

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A method of applying energy optimum control (EOC) when the hybrid electric vehicle performs position control has been developed. As a method of deriving an optimal control law suitable for position control, we attempted a method of adding a virtual drive system driven by a position error signal in the model to be controlled, adding its power consumption to the evaluation function and deriving an optimum control law. In the simulation of the preceding vehicle follow-up, good trackability was not obtained in the rule-based control (RBC) of the comparison, but good follow-up results were obtained in the EOC. The engine energy consumption for EOC was only 85.7% of RBC. In the simulation of the target position stopping, energy consumption was effectively suppressed by the function of the efficiency function of the engine and the motor in the EOC. As a result, the EOC consumed about 92% of the RBC's engine energy consumption.

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A task of carrying is important work for the mobility. In this report, we propose the active carrying table by using the acceleration sensor. These are set on the hand truck. Ant carrying table has two motors to balance the inertial force, gravity force and static friction force. In real world, almost road has convex surface. Then we confirm that the active carrying table is useful when it running through a slope. We consider the two type situations. One situation is that the hand truck goes straight into the slope. Another one is that it crosses through the slope. From the results of experiments, the carrying table can move to balance the exerted force by an acceleration sensor.

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We developed the tribocharge sensor could be built in the rolling bearing to monitor the degradation of grease in the bearing. As a result of our research so far, by analyzing the output of the tribocharge sensor, we have found the possibility of (1) measurement of the bearing rotation speed, (2) estimation of the bearing internal temperature, and (3) sensing the water content in the grease. In this study, the stator electrode was attached to the rear surface of the seal and built in the bearing, and by using the retainer as the rotor electrode, a tribocharge sensor was operated to monitor the water content of grease.

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Mouthguard type sensors have been developed to monitor the biometric information. In order to realize battery-less intraoral sensors, we propose an intraoral electrostatic energy harvester driven by occlusal force. The proposed energy harvester consists of lamination of the electrodes, electret and dielectric elastomer. The energy harvester converts mechanical energy applied by occlusal force into electrical energy by electrostatic induction. In this study, we measured the relationship between the thickness of the electret and the power generation. The experimental results showed the electret of 10 μm thickness was suitable for the proposed energy harvester and it achieved 18.0 μW power generation with the area of 400 mm² under the force equivalent to occlusal force.

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We propose a novel electromagnetic energy-harvesting device (EHD) with a very small and thin structure. The footprint of the device is 20 × 20, the height of the EHD is 7.5 mm, and the volume is 2.4 cm³ . Because the minimum gap between the magnets and iron cores of the coils in the proposed structure can be designed to be very small, a large magnetic flux density differential can be obtained during one power-generation action. This is an advantageous feature of the proposed structure, and the source of the large power generation. According to the experimental results, the proposed EHD generated 102 μW (41.7 μW/cm³ ). Furthermore, the performance of the proposed EHD exceeded the target amount of power generation required to drive recently developed low-power wireless sensors, which can be driven with 100 μW of power.

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By the subject "digital production processing of the fourth grader," I lectured in an advanced example of production processing and the AI introduction of the use of IoT. Each person gave presentation about manufacturing of 2025 after a workshop of the digital production processing using the smart glass by active learning technique. The student who had not heard machine learning, depths learning was 13%. The student thought the prospective field to be automatic driving (85%), manufacturing industry (75%), agriculture (75%), medical care (65%) about application of the AI. The ratio of student who replied it when I wrestled as a relation person with the AI after the entering a company positively was 65%, but the student whom I answered that I wrestled unwillingly was 25%.When an AI subject was opened a course in, 20% of students studied it, and 50% of students had the hope that they attended for trial.The image that the student who experienced CAD, 3D printer training worked on AI,IoT positively was formed.

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Triboelectric power generators are extensively studied because of their high efficiency, low manufacturing cost, and high output voltage. However, the internal impedance of the generator is extremely high, the output power conversion efficiency is lowered, and its practical use has been limited. Therefore, in order to increase the output power by matching the high output impedance of the triboelectric power n generator, we studied a passive power management circuit that turns on and off the unidirectional switch by deformation of the friction generator, drives the coupling inductor, and charges the capacitor after bridge rectification. As a result, about 9 times the output power conversion efficiency was confirmed as compared with that charged directly after the bridge rectification.

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Reliability of a precision optical unit is required especially in a high-temperature and high-humidity environment for in-vehicle uses. The optical unit has to be hermetically sealed to prevent optical elements from performance degradation. For the reliable design of hermetically sealing structure, it is important to quantify the amount of water that permeates rubber parts such as O-rings used for leak stoppers of enclosure joints. In this report, quantification method of permeating water is described with a deformation analysis considering super elasticity of the rubber and a diffusion analysis under the deformed condition of the rubber.

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For high capacity hard disk drive (HDD), Helium is widely used to reduce disk flutter which deteriorate positioning accuracy largely. In order to know Helium effect, we studied disk flutter in Helium condition using laser doppler vibrometer (LDV). In this paper, we changed Helium density, pressure and disk thickness, and then measured disk flutter. The magnitude of disk flutter was inversely proportional to the disk stiffness. And disk flutter was well described by Reynolds number, suggesting disk flutter is excited by fluid force. The result showed not only Helium density but also low pressure is effective for positioning accuracy due to disk flutter.

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In heat-assisted recording hard disks, thermoelectric conversion devices in which p-type and n-type semiconductors are bonded have attracted attention. Sulfides as solid lubricants also have properties of p-type and n-type semiconductors and thermoelectric conversion devices can be constructed. In this research, we describe the synthesis method of sulfide and its properties as a solid lubricant, and report the performance as a thermoelectric.

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We report on the investigation of complex behavior of a rotating flow driven by a pair of corotating disks mounted in a non-axisymmetric enclosure. The flow simulates the fluid flow in hard disk drives (HDD) used as information storage device. In the present study, we made attempts to visualize the secondary flow in planes perpendicular to the disks and to measure the velocity fields in the planes parallel to the disks in the shroudopening area. For the experiments, we used a transparent HDD model equipped with a refractive index matched working fluid. The experiments were performed at two different Reynolds numbers and angles of the arm insertion. The flow visualization revealed vortical motions of the flow in the planes perpendicular to the disks. The velocity fields were obtained based on particle-image analysis in the shroud opening. The results exhibit highly threedimensional and unsteady behavior of the flow in the shroud-opening area.

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The dynamics and stability of a thermal fly-height control (TFC) head slider at close proximity to and touchdown on a magnetic recording disk are attracting considerable research attention, because it is necessary to reduce the head clearance from the lubricant surface to 0.5 nm or less to achieve a higher recording density. This study is intended to develop a simulation algorithm for actual touchdown (TD) and take-off (TO) process by continuously increasing and decreasing head protrusion by TFC power. From numerical simulation, it is found that the simulated TD and TO process show the behaviors similar to the experimental ones except minor differences. The spacing variations during TD and TO process are almost symmetrical as the actual cases. The temporal spacing variations at the transient from light contact to flying state are obtained sometimes in simulation in contrast to experimental results. The strong P2 mode vibration at heavy contact state observed only in experiment is considered to be caused by a self-excited mechanism.

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We improved the performance of a microscopic observation system that has been integrated with a purpose-built pin-on-disk type friction tribotester. This allows us to quantitatively measure the radius and longitudinal depth of deformed region of the sliding pin, and improve the measurement accuracy of the vertical displacement of the sliding pin. As a result, the clearance between the sliding pin and disk can be determined. We found that, even for 1.7 nm thick liquid films, liquid molecules are entrained into the interface between the sliding pin and disk, resulting in upward displacement of the sliding pin and a flattened area at its apex.

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In recent years, it is necessary to reduce the lubricant film thickness in order to increase the capacity of the hard disk drives (HDDs). However, thinning of the lubricant film brings deterioration of the tribological characteristics in head-disk interface. In this study, we made the composite lubricant film and friction tests were conducted to evaluate friction characteristics. As a result, we confirmed the composite lubricant film showed lower surface energy, high bond rate and equal friction coefficient than conventional lubricant film.

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In HAMR system, the lubricant and DLC films are heated to 300–500 °C by laser irradiation, then the thermal reliability of these films and slider smear which is evaporated, thermally decomposed lubricant, or the contamination are critical issues. In this study, we compared the smear amount and the lubricant depletion of disks due to laser heating in air and helium environments using our developed pin-on-disk tester. The evaporated lubricants as smears adhered to a glass pin surface placed 5 µm above the disk. As the results, the amount of smear in helium is more than that in air at high temperatures, but the lubricant depletion in helium was similar to or less than that in air. The dominant mechanisms of lubricant depletion at high temperatures in air and He are decomposition and evaporation/desorption, respectively, determined by TOF-SIMS analysis.

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On-chip concentration is a method of concentrating biomolecules using a nanometer-sized structure created into a microchannel, which is effective for improving detection sensitivity for microfluidic devices. As an on -chip concentration method for DNA molecules, we proposed a concentration method using nanoslit, which was a gap smaller than a diameter of a single molecule. Since this concentration method was based on the principle of entropy trap, its concentration amount depended on applied voltage. In this study, we proposed a theoretical model of concentration using nanoslit and determined an optimal voltage at which maximizing the concentration amount. We fabricated a chip device with 25 nm-depth nanoslit using microfabrication technique and experimentally verified the validity of our model. We achieved the concentration of λ DNA molecules at 17 times when we applied 0.6 V for 15 s.

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In this study, for establishment of method to quantitatively evaluate mechanical properties of growing roots including the driving pressure and Young’s modulus, we fabricated the microchannel device integrated with force displacement sensor. We used Arabidopsis thaliana, a model plant, and observed the root growth behavior by time-lapse observation. By analyzing buckling behavior of the growing root, we estimated the Young’s modulus of the growing root. It will be possible that this method contribute to the selection of soil with optimum hardness and nutrient concentration for various type of plants.

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Our objective is individual driving mirrors in multi-axis scanning Micro Electro Mechanical Systems (MEMS) mirror array by single superposed driving signal. If each vibration mode of the mirrors has separated resonant frequency, the MEMS mirror in the array can be individually by single superposed driving signal composed of sine waves with the resonant frequencies of the modes. To control each mirror of the array individually, we designed beam width and length to control the resonant frequency of each vibration mode. Each frequency is separated by 20 times of each half-value width of the nearest resonant frequency signal. Four types of three-axis scanning MEMS mirror was fabricated into the array. Measuring deflection angles by superposed signal, each vibration mode had been driven independently of sine waves with other resonant frequencies. This result indicated that all vibration mode can be driven individually in the same time.

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In this paper, we propose a diaphragm type vibration energy harvester with a flexible auxetic structure. The proposed energy harvester consists of a piezoelectric layer and an elastic layer, and we applied the flexible auxetic structure to the elastic layer. The auxetic-type harvester deforms largely, and thus, the strain amount in piezoelectric layer increases. Therefore, the improvement of power generation performance can be expected. In addition to the flexibility, a unique deformation behavior of the auxetic structure leads to a further increase of the strain in the piezoelectric material. According to FEM analysis, the proposed auxetic-type harvester achieved lower resonance frequency and higher output power than the conventional flat-type harvesters. In addition, the auxetic-type harvester obtained 27% improvement of output power that is originated from the unique deformation of the auxetic structure.

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The high-resolution observation of bacteria in culture is one of the promising approaches to discover new action mechanisms of antibacterial agents. Atmospheric scanning electron microscope (SEM) achieved in-liquid observation. We previously improved atmospheric SEM and developed MEMS (Microelectromechanical Systems) liquid cell for the culture of bacteria under SEM observation. MEMS liquid cell required liquid medium for bacterial culture. This caused the low spatial resolution due to the electron scattering and the movement of bacteria due to the medium flow. We developed a microfluidic agar device to culture bacteria without liquid medium. An agar channel of 20 μm in height was fabricated by a PDMS mold, and a hydrophobic pattern was stamped on a glass substrate. By the combination of the agar channel and hydrophobic pattern, dyed water was introduced into the agar channel without the leakage.

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Online monitoring of cellular metabolism involved in cell growth and differentiation contributes to evaluate cellular condition in cell-based assays. However, conventional methods of cellular monitoring measure discrete time-based data of cell conditions, because the methods rely on intermittent sample extraction. Therefore, a novel online measurement method is highly required to obtain more detailed and dynamic information about cell activities. In this study, we developed a microfluidic device integrated with a glucose sensor having an automatic calibration function. To validate functions of the device, we measured glucose consumption of HepG2 cells and it toxicities using the device. As a result of our preliminary test, the online measurement of the difference of glucose concentration by cells succeeded using the device.

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