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20-μm-diameter WGM resonators that include a terfluorene emission layer and a 10-nm-thick layer of Al or Ag were investigated. The plasmon-quenching effect on amplified spontaneous emission was effectively suppressed by the resonator structure.

This paper reports on the improvement of the output power of piezoelectric energy harvesters (PEHs). A tapered thickness structure of a cantilever beam for uniform stress, tungsten proof mass, thick piezoelectric film, and series connection of the piezoelectric films are utilized for PEHs to increase the output power. The three-dimensional (3D) etching process of Si enables the formation of tapered thickness beam structure, which increases not only the output power, but the beam strength. The 3D shape allows to increase the weight of the proof mass, contributing to increase the output voltage and power. Furthermore, output voltage is enhanced by using series-connection of PZT cells to improve the circuit efficiency. The open-circuit output voltage and optimum power with resistance load of the fabricated harvesting device revealed 14.4 V0-P and 92 mu W at an acceleration of 9.8 m/s(2). The output power was improved by 8.9 times higher than that of the conventional model.

This paper reports thickness controls for cantilever beams of the piezoelectric energy harvester (PEH). The uniform stress structure for increasing output power and fillet structures for stress concentration relief of cantilever beams were fabricated by thickness controls using the micro-loading effect, resulting in a 46% increase in power generation and a nearly two-fold increase in fracture strength compared to typical cantilever beams.

To evaluate the characteristics of Pb(Zr,Ti)O3 (PZT) thin films (about [Formula: see text] thick) with three different sputtering configurations-single-layer (SL) deposition, multilayer (ML) deposition with internal electrodes, and multistep (MS) deposition-were prepared. The SL films exhibited poorer dielectric characteristics than the ML and MS films. The reliability and piezoelectric characteristics were especially high in the MS film, with an [Formula: see text] constant of -9.5 C · m-2. To investigate the porosity of the films, reconstructed 3-D SEM technique is employed. Reconstructed 3-D SEM images revealed decreased void densities in the ML and MS films, which improved their performance. The MS configuration provided the best dielectric and piezoelectric performance of PZT films.

Purpose To develop anin vivodosimeter system for stereotactic body radiation therapy (SBRT) that can perform accurate and precise real-time measurements, using a microsized amount of a photostimulable phosphor (PSP), BaFBr:Eu2+. Methods The sensitive volume of the PSP was 1.26 x 10(-5) cm(3). The dosimeter system was designed to apply photostimulation to the PSP after the decay of noise signals, in synchronization with the photon beam pulse of a linear accelerator (LINAC), to eliminate the noise signals completely using a time separation technique. The noise signals included stem signals, and radioluminescence signals generated by the PSP. In addition, the dosimeter system was built on a storage-type dosimeter that could read out a signal after an arbitrary preset number of photon beam pulses were incident. First, the noise and photostimulated luminescence (PSL) signal decay times were measured. Subsequently, we confirmed that the PSL signals could be exclusively read out within the photon beam pulse interval. Finally, using a water phantom, the basic characteristics of the dosimeter system were demonstrated under SBRT conditions, and the feasibility for clinical application was investigated. The reproducibility, dose linearity, dose-rate dependence, temperature dependence, and angular dependence were evaluated. The feasibility was confirmed by measurements at various dose gradients and using a representative treatment plan for a metastatic liver tumor. A clinical plan was created with a two-arc beam volumetric modulated arc therapy using a 10 MV flattening filter-free photon beam. For the water phantom measurements, the clinical plan was compiled into a plan with a fixed gantry angle of 0 degrees. To evaluate the energy dependence during SBRT, the percent depth dose (PDD) was measured and compared with those calculated via Monte Carlo (MC) simulations. Results All the PSL signals could be read out while eliminating the noise signals within the minimum pulse interval of the LINAC. Stable real-time measurements could be performed with a time resolution of 56 ms (i.e., number of pulses = 20). The dose linearity was good in the dose range of 0.01-100 Gy. The measurements agreed within 1% at dose rates of 40-2400 cGy/min. The temperature and angular dependence were also acceptable since these dependencies had only a negligible effect on the measurements in SBRT. At a dose gradient of 2.21 Gy/mm, the measured dose agreed with that calculated using a treatment planning system (TPS) within the measurement uncertainties due to the probe position. For measurements using a representative treatment plan, the measured dose agreed with that calculated using the TPS within 0.5% at the center of the beam axis. The PDD measurements agreed with the MC calculations to within 1% for field sizes Thein vivodosimeter system developed using BaFBr:Eu(2+)is capable of real-time, accurate, and precise measurement under SBRT conditions. The probe is smaller than a conventional dosimeter, has excellent spatial resolution, and can be valuable in SBRT with a steep dose distribution over a small field. The developed PSP dosimeter system appears to be suitable forin vivoSBRT dosimetry.

Using a a-axis-oriented epitaxial (Bi3.25Nd0.65Eu0.10)Ti(3)O(1)2 (BNEuT) thin films with a microplate-like shape as a ferroelectric pillar material, micropillar-type CoFe2O4 (CFO)/BNEuT(h00)/Nb:TiO2(101) composite multiferroic films were fabricated by metal organic chemical vapor deposition. The deposition time was varied from 90-150 min to examine its effect on the structural, ferroelectric, and ferromagnetic characteristics of the films. All the films exhibit single-phase cobalt ferrite with a cubic inverse-spinel structure. The deposited CFO films have a similar columnar structure with a comparatively good step coverage of 37%-66%. The room-temperature magnetization-magnetic field hysteresis loop of the films showed a clear ferromagnetic hysteresis loop, and coercivity decreased from 1.1 to 0.9 kOe with increasing the deposition time. The room-temperature polarization-electric field hysteresis loop of the films showed a ferroelectric hysteresis loop, and the effect of the leakage current was the smallest for a deposition time of 120 min. (C) 2019 The Japan Society of Applied Physics

CoFe2O4 (CFO) thin films were deposited on (Bi3.25Nd0.65Eu0.10)Ti3O12 (BNEuT) micropillar films by a non-aqueous sol-gel method. The pitch size of 2-5 mu m in the micropillar films used as ferroelectric pillars, and 5 and 15 CFO deposition cycles were examined for high density of CFO nanoparticles. All the CFO films formed by five deposition cycles on BNEuT micropillar films with a pitch size of 2-5 mu m were composed of mostly single-phase CFO with a cubic inverse-spinel structure. All the CFO films deposited on the four BNEuT micropillar films were highly dense and had excellent surface flatness, based on surface field-emission scanning electron microscope observations. Based on the structural, magnetic and ferroelectric characteristics, the optimal pitch size for achieving a high density of CFO nanoparticles was 5 mu m, and the optimal number of CFO deposition cycles was five. (C) 2019 The Japan Society of Applied Physics

© 2020 IEEE. This paper reports the first demonstration of Ultra-Low-Power (ULP) operation below 1 μW and noise reduction realized by a monolithic 3-axis accelerometer using a SiGe-MEMS-on-CMOS technique. In this work, the ULP operation is attributed to incorporating high-sensitivity SiGe-MEMS and low-power CMOS circuit with a monolithic configuration. The power consumption is confirmed to be 273 nW in an active mode and 160 nW in a standby mode. Furthermore, this work first evaluates the quantitative benefit of the monolithic configuration in view of noise reduction, and the result is a 30% lower noise density compared to a two-chip configuration using wire bonding, stemming from a 53% reduction of the parasitic capacitance. This work's approach enabling ULP operation and the noise reduction will contribute to the long battery life of sensors desired for IoT applications.

© Published under licence by IOP Publishing Ltd. Multilayered piezoelectric MEMS energy harvesters based on sputtering depositions are designed and fabricated. To obtain high endurance and output power, the unimorph cantilever structure with totally 10 μm-thick multilayered PZT thin films and 80 μm-thick Si elastic layer is designed. In addition, the cantilever is designed to undergo a uniform stress on the PZT. The output power and voltage was 90 μW and 1.0 Vrms under the input acceleration of approximately 1.2 G (=11.76 m/s2) and optimum load resistance.

Accumulated charge measurement (ACM) is a new experimental technique for organic semiconductors to evaluate the charge injection barrier at the semiconductor-metal interface directly using a metal-insulator-semiconductor-metal (MISM) capacitor. In this technique, the precise estimation of the electrostatic capacity of the insulator layer (C-I) is required for the analysis. The information of this parameter is, in principle, included in the ACM data; however, it is not directly evaluated because of the error resulting from the charge-spreading effect in an organic MISM capacitor with an unrestricted electrode structure. Therefore, the C-I in previous ACM experiments has been independently estimated from the area of the electrode. In this study, a novel design of a substrate with a restricted-bottom-electrode structure is reported. Using the newly designed substrate, it was possible to suppress the charge-spreading effect and successfully estimate precise values of C-I directly from the ACM data. Subsequently, it was possible to evaluate the injection barriers at the metal-free phthalocyanine (H2Pc)-Ag and pentacene-Au interfaces, which were 0.4 and 0.15 eV, respectively. The built-in potentials in the semiconductor layer were also determined for the samples used in the measurement.

The influence of design parameters of piezoelectric thin films on the performance of vibration-type piezoelectric energy harvesting devices is investigated experimentally. The devices have four layers of Pb(Zr,Ti)O-3 thin films on a silicon-based microfabricated structure to obtain high output power. The initial deformation and output power are measured. The results indicate that the initial shape due to residual stress can influence the mechanical quality factor and output power, particularly for the low-acceleration regime. In addition, the influence of the weight of the mass is investigated by changing the weight of the harvester. It is experimentally demonstrated that the power density and the generative power's ratio to the theoretical limit can be improved by increasing the weight. A very large value of the normalized power density, 55.45 mW cm(-3) G(-2) (1 G = 9.8 m s(-2)), is obtained when a tungsten mass is attached to the microfabricated harvesting device. (C) 2019 The Japan Society of Applied Physics

The ship navigation in a bay and harbor is one of the difficult situation for the congested sea area, and a coastal radio operator (port coordinator) usual supports a safe navigation by giving useful navigational information. The navigators make decision to avoid collision, and recognize the navigational situations from their information. In the other word, they manage the safe harbor traffic to control by giving the useful information. We think that their mental and physical workload shows the current and near future harbor traffic condition, and to monitor their workloads leads safe harbor control. In this study, we aim the development of monitoring system for port coordinators as the system of systems toward safe harbor traffic, and we measure ECG, body accelerations, and etc. The measured data read the mental and physical workload for the real situations of the harbor traffic. The results show the heart rate variability (R-R interval) and body accelerations read their mental and physical workload, and that displayed performance is well in the real time.

In this study, we aimed to develop a smart-cloth for workout. A flexible elastic electrode by using silicone rubber with special carbon black material, KETJENBLACK, was fabricated and tested. The flexible conductive electrode having an expansion ability of 100% or more was successfully fabricated. The compound of special carbon black, KETJENBLACK, can offer flexible electrodes and be suitable for wearable devices.

© 2019 The Institute of Electrical Engineers of Japan. Tactile devices that provide touch sensation to humans by direct contact have been realized. A tactile device based on a piezoelectric MEMS is improved in this study. The driving voltage is lowered by using multilayer lead zirconate titanate (PZT) thin film. The lower voltage is experimentally validated by measuring the cantilever displacement in the device. The displacement per voltage becomes four times larger by using four layers of PZT thin film. In addition, the polymer supporting material is also investigated to reduce the temperature dependence of the device. By using polyimide as an alternative to conventional SU-8, not only the initial warpage but also the temperature dependence is dramatically improved. The driving test of the polyimide device reveals cantilever displacement comparable to that in conventional devices. In conclusion, structural improvements resulted in low-voltage actuation and reduced warpage of the piezoelectric MEMS tactile device.

For the application of bidirectional communication between a human activity monitoring system and a human using tactile sensation, a tactile MEMS device is developed. To obtain the displacement and provide energy to the human skin, a driving actuator and a displacement sensor are integrated. The tactile device is based on a cantilever with a lamination structure of polymer and Pb(Zr,Ti)O-3 thin films. The characterization of the device showed that the sensor output agreed well with the tip displacement. For the touch experiment of the device, the frequency response demonstrates hardening-spring-like behavior. By using a piecewise linear system model, the behavior is analyzed. The experimental results and analytical model showed similar tendencies. These results indicate a potential application of the stiffness sensor of an object. (C) 2018 The Japan Society of Applied Physics

This study aims to report the design of high-performance piezoelectric MEMS energy harvesters using a full batch MEMS-fabrication process with a Si proof mass and multilayered Pb(Zr,Ti)O-3 (PZT) thin films without bonding of a proof mass and/or bulk piezoelectric ceramics. These devices contain sputtered multilayered PZT thin films with internal metal electrodes as a thick energy-conversion layer. The thickening of the piezoelectric layer by multilayer sputter deposition technique enabled the batch fabrication of high-performance piezoelectric MEMS harvesters. These fabricated device with the footprint of 10 x 10 mm(2) was found to provide a high output power of 53.7 mu W per gravitational acceleration. These results are expected to be useful for the future development of alternatives to batteries for autonomous sensor systems. (C) 2018 Elsevier B.V. All rights reserved.

<p>Blood pressure changes every second and cannot be continuously monitored by conventional cuff method. In order to solve this problem, we proposed a blood pressure estimation system by pulse transit time (PTT) method. The system includes two devices; a master device which monitors ECG for starting time of the pulse wave, and a slave device for monitoring the propagated pulse wave at the wrist. Both devices have some sensors, such as an accelerometer and barometer, for monitoring the condition of the body and wrist. The detected condition will be used for compensation of the PTT data. As a result, estimation of the blood pressure by PTT is accurate enough comparing to sphygmomanometer for home use. In addition, the relation between barometric pressure and PTT by hand position was measured and used for establishing the correction equations.</p>

<p>センサ・マイクロマシン部門（E部門）では，生体情報をセンシングする技術に関連した論文・レターを集めた特集号を企画し，本誌の2018年12月号で今回の特集号を発行する運びとなりました。</p><p>人工知能，ビッグデータの急速な進展において，生体情</p>

In the maritime society, the training of a ship handling is carried out by a ship bridge simulator. The education using the simulator is popular worldwide because we are able to educate the same scenario, and repeat it for a lot of students until they can understand well. Moreover, we can make a scenario for the dangerous conditions and situations that we have never tried on the real vessel. The evaluation of simulator training is subjectively; it is professional subjective evaluation that comes from their experiences. In this paper, we propose a real time evaluation support system using a physiological index as the one of system of simulator systems. The system evaluates mental workload on the real time, and the system supports instructors to monitor student's mental workload during their training. The instructors understand not only their performance but also their mental workload to evaluate the training.

We have been developing a wearable device to observe the state of the human body and its circumstance. In previous studies, an ASIC (application specific integrated circuit) that provides heart rate from ECG (electrocardiogram) signal without the aid of a MPU(micro processing unit) processing was successfully developed. As a result, we drastically reduced the power consumption of the system to 2% compared with our previous system. In this study, a test model that integrates the ASIC and all other circuits including a low power MPU is constructed by using a FPGA to verify the operation of the complete system. The system operation of the test model mounted on the actual human body is confirmed on the PC based user interface software.

This paper describes the resonant type magnetic sensor completely compatible to the micro electromechanical systems (MEMS) batch fabrication process of SiGe. The resonant vibration of the sensor is excited by the Lorentz force that is proportional to the driving current and applied magnetic field. Since the sensitivity of the sensor reaches the order of geomagnetic field, the magnetic sensor can be incorporated into inertial measurement unit (IMU), which is fabricated with accelerometer and gyroscope. In addition, low deposition temperature of SiGe is advantageous to realize the monolithic integration of IMU combo sensors onto CMOS circuit. For inspection, the test device was fabricated with Si-SOL

<p>In training institutions for care workers, incorrect operation often causes a pain in the lower-back to trainees. The instructors have difficulty in judging whether the trainees perform an operation correctly without monitoring muscle activity in the lower-back. Accordingly, the purposes of the present study were (a) to produce a sensor to measure muscle activity in the lower-back and (b) to develop the education support system which shows the instructors a simultaneous display of muscle and physical activities in the lower-back and video of the operations. The experimental sensors consist of six channel electromyogram (EMG) sensors, three-axis acceleration, angular velocity and geomagnetic sensors. The software for data acquisition which records data from individual sensors synchronously was developed using LabVIEW 2015. Using this all-in-one experimental sensor system, five subjects had their lower-back muscle activity measured while lifting a dumbbell. The data acquired was compared to the data from the same experiment monitored by existing, commercially available non-integrated systems. Consequently, the experimental system could record the data smoothly from the sensors on the lower-back as expected. The integrated EMG values of the erector spinae muscles obtained by the experimental system and the commercially available EMG system had a strong positive correlation. Hereafter, our work will be to validate the experimental system by comparing the other data sources to existing sensor systems.</p>

The evaluation of simulator-based exercise in maritime society depends on specialists who have enough on-board experience like a master and/or a professor of maritime university. That is just subjective evaluation, and the reviewed data is performance of the operated vessel such as own ship course, speed, rudder angle, and their behavior on order, action, and so on. We propose that their inside response (mental workload) is also important data to evaluate their simulator-based exercise using physiological index; moreover, we have found the heart rate variability, facial (nasal) temperature, and saliva are efficient to read their mental workload. However, the evaluation was not real time yet, it is just off-line analysis. The real time data is available that the instructor gives trainee the useful advisements on the spot during the exercise. In this paper, we propose a monitoring system as an evaluation support system for simulator-based exercise using heart rate variability, and we confirm its possibility.

The silicon molding technique is described for patterning of NdFeB/Ta multilayered magnetic films and NdFeB magnetic powder at the micron scale. Silicon trenches are seamlessly filled by 12-mu m-thick NdFeB/Ta multilayered magnetic films with a magnetic retentivity of 1.3T. The topography image and magnetic field distribution image are measured using an atomic force microscope and a magnetic force microscope, respectively. Usingasiliconmoldingtechniquecomplementedbyalift-offprocess, NdFeB magnetic powder is utilized to fabricate magnetic microstructures. Silicon trenches as narrow as 20 mu m are filled by a mixture of magnetic powder and wax powder. The B-H hysteresis loop of the patterned magnetic powder is characterized using a vibrating sample magnetometer, which shows a magnetic retentivity of approximately 0.37 T. (C) 2011 Elsevier B.V. All rights reserved.

Continuous observation of human activities and circumstances are quite important for healthcare applications that collect a lot of data from the various MEMS (Micro Electromechanical Systems) sensors. This study demonstrates the multi-environmental sensing system for human applications that can measure the time-based three-axes acceleration (threeaxes shock), barometric pressure, temperature and relative humidity, simultaneously. The system has battery and large sized memory for autonomous sensing. The measured data are stored in a flashmemory via an onboard microcontroller. The detailed configurations of the prototype device and some experimental results are investigated.

A lot of energy harvesting devices using electret material has been developed. Since the power from the electret energy harvester is proportional to the surface charge concentration, i.e. charged voltage on the electret, frequency and dynamic range of the capacitance change. To fabricate the electret, the corona discharge is a very popular charging method that consists of a high voltage needle for corona ions generation, and a grid electrode applying a bias voltage that implants the electrons from corona ions to the electret material. In this study, we introduce a novel charging method with fine patterns using the buried grid-electrodes applied with a bias voltage. We also describe FEM analysis and experimental results. (C) 2010 Published by Elsevier Ltd.

This paper presents a monolithically integrated multi-sensor system for the intelligent data carrier(IDC). The system includes a three-dimensional accelerometer, pressure sensor, temperature sensor and humidity sensor as well as the peripheral circuitry for each sensor on one chip. The peripheral circuitry was designed to combine them to one-chip microprocessor with A/D converter. The monolithic multi-sensor chip was realized using an SOI wafer, where the Deep-RIE bulk-micromachining process and bipolar IC process were used for sensor device fabrication and circuit fabrication, respectively.