Details of a Researcher - Takahashi, Hidetoshi

Papers - Takahashi, Hidetoshi

Division display 141 - 160 of about 284 ／ All the affair displays >>

Direct Fabrication of PEGDA Micro Suction Cup Array Using Inclined/Rotating Mirror Exposure System

T Sugimoto, H Takahashi

2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)) 2020-January 925 - 927 2020

ISSN 1084-6999

This paper reports on direct fabrication method of a PEGDA micro suction cup array. A micro suction cup has been attracted in many application, however, conventional fabrication method using mold has limitation of the shape of the fabricated structure. The proposed fabrication method realizes a micro suction cup array with single exposure dose by inclined/rotating exposure system. As the suction cup material, UV curable Poly (ethylene glycol) diacrylate (PEGDA) is used due to its suitable characteristics. By controlling the inclined angle and mask pattern, the shape of micro suction cup can be designed. We conducted fabrication experiment of suction cup array of 200 mumathrm{m} in diameter to confirm our proposed method is useful.

Access to Document (DOI)

Densely Arrayed Active Antennas Embedded in Vertical Nanoholes for Backside‐Illuminated Silicon‐Based Broadband Infrared Photodetection

S Yasunaga, H Takahashi, T Takahata, I Shimoyama, T Kan

Advanced Materials Interfaces 7 (21), 2001039 2020

3D Hydrogel Manufacturing Employing Self-Focusing During Photo-Curing Process

G Lee, H Takahashi, T Kan, J Kim, N Donmez, J Park, D Kim, S Ka, ...

2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems … (Institute of Electrical and Electronics Engineers Inc.) 2020-January 323 - 324 2020

ISSN 1084-6999

This work proposes a 3D lithography technique with self-focusing during polymerization based on refractive-indices change of polyethylene glycol diacrylate (PEGDA) (Fig. 1). Compared to the previous work, the present work enables to fabricate 3D structures using single UV exposure and theoretically estimate 3D features. We demonstrate the potential of the self-focusing 3D lithography by fabricating PEGDA microneedles and trapezoid-shaped wells. Their structures well match to our theoretical estimation. Therefore, our theoretical approach shows its potential for on-demand, complicated 3D structures of refractive-indices-variable materials with single UV exposure.

Access to Document (DOI)

Assessment of the risk of malnutrition due to aspiration pneumonia and oral feeding difficulty

S Sato, H Takahashi

Nutrición hospitalaria: Órgano oficial de la Sociedad Española de Nutrición … 2020

Applicability of Plasmonic Photodetectors with Dynamic Reconfiguration of Detectable Wavelength for Spectroscopy

Oshita Masaaki, Takahashi Hidetoshi, Ajiki Yoshiharu, Kan Tetsuo

The Proceedings of the Symposium on Micro-Nano Science and Technology (The Japan Society of Mechanical Engineers) 2020.11 27P3-MN3-6 2020

This paper reports a reconfigurable plasmonic photodetector with a micro electro mechanical system (MEMS) angular modulator for application of miniaturization of a near-infrared spectrometer. The structure of this research has a plasmonic gold diffraction grating capable of detecting the corresponding wavelength at a specific incident angle on an n-type Si cantilever. We confirmed that the peak of the photocurrent signal from the fabricated device occurred at different incidence angles depending on the wavelength. To demonstrate the applicability of the photodetector, spectroscopy was performed from the photocurrent signals from the device. The spectra calculated from the signals was consistent with the spectra from the commercial spectrometer.

A MEMS-based measurement system for evaluating the force-length relationship of human induced pluripotent stem cell-derived cardiomyocytes adhered on a substrate

K Matsudaira, H Takahashi, KH Shoji, TV Nguyen, T Tsukagoshi, ...

Journal of Micromechanics and Microengineering (IOP PUBLISHING LTD) 29 ( 5 ) 2019

ISSN 09601317

© 2019 IOP Publishing Ltd. This paper reports on a method for evaluating the force-length relationship of adhering human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) on the substrate using a measurement system comprising of a micromachined movable plate and a piezoresistive force probe. The cells on the plate are stretched by pushing the movable plate with the piezoresistive cantilever, which is actuated by a piezo stage. The twitch forces and the applied stretch are measured quantitatively with the piezoresistive cantilever. The results demonstrated that the twitch forces of the hiPSC-CMs increased when a stretch was applied. This evaluation method improves the understanding of the intrinsic force-length relationship of hiPSC-CMs at the cellular scale.

Access to Document (DOI)

Sensor

I Shimoyama, K Matsumoto, BK Nguyen, H Takahashi, MD Nguyen, ...

US Patent App. 10/234,429 2019

Highly sensitive and low-crosstalk angular acceleration sensor using mirror-symmetric liquid ring channels and MEMS piezoresistive cantilevers

H Takahashi, T Kan, A Nakai, T Takahata, T Usami, I Shimoyama

Sensors and Actuators A: Physical 287, 39-47 (ELSEVIER SCIENCE SA) 287 39 - 47 2019

ISSN 09244247

© 2019 This paper describes an angular acceleration sensor that uses liquid ring channels and piezoresistive cantilevers. The detection of fluidic rotation has attracted attention as a sensing principle for angular acceleration due to the simple structure and potentially low power consumption of devices that use said principle. Although the existing angular acceleration sensors that use this sensing principle have the potential for high sensitivity to angular acceleration about the target axis, crosstalk is an issue—specifically, crosstalk with angular accelerations about other axes and with linear acceleration. Here, we propose an angular acceleration sensor that uses a MEMS piezoresistive cantilever as the sensing element and two mirror-symmetric ring channels. This mirror symmetry cancels out the signals due to accelerations about the other axes, while the signal for the angular acceleration about the target axis is doubled. The experimental results show that the sensitivity to other axial angular accelerations and linear acceleration is sufficiently small. The obtained sensitivity for the angular acceleration is as high as 3.1 × 10 −4 (rad/s 2 ) -1 , similar to theoretical predictions. This value for the sensitivity is maintained over a range of frequencies from 0.1 Hz to 100 Hz. Therefore, the proposed sensor is suitable for practical angular acceleration detection applications.

Access to Document (DOI)

Underwater Pitot Tube for Swimming Animals

T Hagiwara, H Takahashi, TV Nguyen, T Takahata, I Shimoyama

2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)) 2019-January 95 - 98 2019

ISSN 9781728116105

© 2019 IEEE. This paper reports on an underwater Pitot tube which is designed for swimming measurement of marine animals. The tubes of the Pitot tube are filled with incompressive liquid and sealed by thin films so that the device can be used even when plunged into water. The Pitot tube has a pressure sensor inside that consists of a piezoresistive cantilever incorporated into a thin Parylene-C membrane. When a water flow is applied to the Pitot tube, the thin films at the inlets act as elastic membranes and the liquid filled in the tubes transmits the pressure to the pressure sensor. The proposed Pitot tube can be used as a water flow speedometer for biological studies of marine animals.

Access to Document (DOI)

An MRI-Compatible Force Sensor with Enclosed Air Using Pressure Transmission

D Akutagawa, T Izumizaki, M Hori, H Takahashi, I Shimoyama, T Dohi

2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)) 2019-January 803 - 806 2019

ISSN 9781728116105

© 2019 IEEE. We fabricated an MRI-compatible force sensor with enclosed air using pressure transmission. The fabricated force sensor consists of a contact portion, sensing portions, and connecting pipes. When force was applied to the contact portion, the internal air pressure increased with a deformation of the contact portion, and is transmitted to the sensing portion through the connecting pipes. In the sensing portion, the change in air pressure is detected by a change in the resistance of a piezoresistive cantilever. Since using this air pressure transmission, the sensing portion can be placed away from the magnet of the MRI. Therefore, the force sensor does not interfere with the magnetic field, and it can be used in the magnet of an MRI.

Access to Document (DOI)

Highly Sensitive Angular Accelerometer Utilizing Piezoresistive Cantilever and Spiral Liquid Channel

B Jo, H Takahashi, T Takahata, I Shimoyama

ISSN 9781728116105

© 2019 IEEE. This paper reports a highly sensitive angular accelerometer utilizing a piezoresistive cantilever and spiral liquid channels. The spiral structure increases the total inertial force of liquid due to angular acceleration, which leads to the sensitivity enhancement. The differential pressure between two spiral liquid channels was measured by a piezoresistive cantilever with the resolution of 0.01 Pa. The developed sensor with number of turns of the spiral with 25 achieved the sensitivity enhancement by 28.5 times, compared to the ring channel sensor.

Access to Document (DOI)

In-Plane Gyroscope Using a Piezoresistive Beams with Sidewall Doping

K Abe, H Takahashi, T Takahata, I Shimoyama

ISSN 9781728116105

© 2019 IEEE. This paper reports a gyroscope using sidewall doped piezoresistors and vibrating mass by Lorentz force. With sidewall doped piezoresistors, in-plane deformation of the beams due to Coriolis force generated by angular motion can be detected, which was difficult with surface doped piezoresistors. The proposed gyroscope was designed so that the resonant frequencies of the driving and sensing modes were similar to each other. It was demonstrated that the developed gyroscope measured angular velocity through the resistance change of the piezoresistive beams.

Access to Document (DOI)

Infrared Photodetector with Copper Resonator in Silicon Nanohole Array

S Yasunaga, T Kan, H Takahashi, T Takahata, I Shimoyama

2019 20th International Conference on Solid-State Sensors, Actuators and … (2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII) 633 - 636 2019

ISSN 9781728120072

© 2019 IEEE. A silicon-based infrared photodetector with metal nanostructures has been drawing attention, while lacking sufficient responsivity. We hereby present a silicon-based infrared photodetector furnished with an array of a nano-scale copper plate which induces localized surface plasmon resonance (LSPR). Each plate is placed at the bottom of a nanohole on a silicon substrate. This device possesses two features: electrically-connected copper resonators and backside-illuminating configuration. They lead to efficient photocurrent generation. As LSPR couples with vertically incident light, this structure can be a solution of realizing a silicon-based infrared photodetector that can be adapted to prevalent semiconductor devices.

Access to Document (DOI)

Monitoring Volcanic Activity with High Sensitive Infrasound Sensor Using a Piezoresistive Cantilever

J Shimatani, H Takahashi, M Ichihara, T Takahata, I Shimoyama

ISSN 9781728116105

© 2019 IEEE. In this paper, we propose a high sensitive monitoring method of infrasound evoked by a volcano eruption. The sensor unit is composed of two differential pressure sensors and an air chamber. The pressure resolution of the developed sensor is approximately 0.01 Pa, which is sufficiently small to detect the tiny infrasound. The measurable frequency range is from 0.3 Hz, which is sufficiently low for the infrasound. The sensor units were set at the foot of volcano, Sakurajima, Kagoshima, Japan. It was confirmed that the sensors kept the high sensitive monitoring performance for a month.

Access to Document (DOI)

Waterproof airflow sensor for seabird bio-logging using a highly sensitive differential pressure sensor and nano-hole array

Hidetoshi Takahashi, Akihito Nakai and Isao Shimoyama

Sensors & Actuators A: Physical (ELSEVIER SCIENCE SA) 281 243 - 249 2018.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 09244247

This paper presents an airflow sensor for seabird bio-logging. Although bio-logging methods have attracted attention in the evaluation of seabird flight performance, the airflow velocity has not been directly measured. Here, an airflow sensor is added to the bio-logging system, and a direct airflow velocity measurement is applied, thus enabling more accurate evaluation of the flight performance. To attach the sensor to the bio-logging system, the sensor must be waterproof because seabirds dive into the sea to prey on fish. In addition, the sensor must also be compact and have high sensitivity. Here, we propose a Pitot tube-type airflow sensor that satisfies these requirements. The proposed sensor is composed of microelectromechanical systems (MEMS) piezoresistive cantilevers as sensing elements with high sensitivity and anodic alumina membranes with a nano-hole array as the waterproof elements with airflow penetration. The developed sensor responded sufficiently to airflow velocities from 2 m/s to 20 m/s. In addition, the sensor maintained its sensitivity after plunging into the water and returning to the air. Therefore, the proposed sensor can be utilized for practical seabird bio-logging. (C) 2018 Elsevier B.V. All rights reserved.

Access to Document (DOI)

Experimental study of the aerodynamic interaction between the forewing and hindwing of a beetle-type ornithopter

Hidetoshi Takahashi, Kosuke Abe, Tomoyuki Takahata, Isao Shimoyama

Aerospace (Aerospace) 5 ( 3 ) 83 2018.08

Research paper (scientific journal), Joint Work, Accepted

© 2018 by the authors. Beetles have attracted attention from researchers due to their unique combination of a passively flapping forewing and an actively flapping hindwing during flight. Because the wing loads of beetles are larger than the wing loads of other insects, the mechanism of beetle flight is potentially useful for modeling a small aircraft with a large weight. In this paper, we present a beetle-type ornithopter in which the wings are geometrically and kinematically modeled after an actual beetle. Furthermore, the forewing is designed to be changeable between no-wing, flapping-wing, or fixed-wing configurations. Micro-electro-mechanical systems (MEMS) differential pressure sensors were attached to both the forewing and the hindwing to evaluate the aerodynamic performance during flight. Whether the forewing is configured as a flapping wing or a fixed wing, it generated constant positive differential pressure during forward flight, whereas the differential pressure on the hindwing varied with the flapping motion during forward flight. The experimental results suggest that beetles utilize the forewing for effective vertical force enhancement.

Access to Document (DOI)

薄膜メタマテリアル実現に向けたフレーム構造のTHz応答解析

磯崎瑛宏, 菅哲朗, 高橋英俊, 松本潔, 下山勲

電気学会論文誌E 138 ( 7 ) 281 - 286 2018.07

Research paper (scientific journal), Joint Work, Accepted

Development of a light source with a uniform intensity reinforced by a checkerboard half-mirror positioned within inverse L-shaped UV-LED arrays

Hidetoshi Takahashi, Isao Shimoyama and Yun Jung Heo

Applied Physics Express (Applied Physics Express) 11 ( 6 ) 066701 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 18820778

© 2018 The Japan Society of Applied Physics. This paper presents a simple, low-cost, long-lasting UV-LED-based light source with uniform light intensity using a checkerboard half-mirror positioned within inverse L-shaped UV-LED arrays. The light rays from the top UV-LED array passed through the transparent portions of the checkerboard half-mirror, while the light rays from the side UV-LED array were reflected on the remaining opaque portions at right angles. Thus, uniform light intensity was achieved on the bottom area. Using the developed UV-LED light source, we fabricated microstructures with uniform shapes on a large area, thereby showing feasible applications for MEMS fabrication.

Access to Document (DOI)

Silicon-based Nano-hole IR Detector with Supercritical Fluid Deposition of Copper

Yasunaga Shun, Takahashi Hidetoshi, Kan Tetsuo, Tsukagoshi Takuya, Momose Takeshi, Takahata Tomoyuki, Shimoyama Isao

JSAP Annual Meetings Extended Abstracts (The Japan Society of Applied Physics) 2018.1 3128 - 3128 2018.03

Access to Document (DOI)

Cellular dynamics of bovine aortic smooth muscle cells measured using MEMS force sensors

Takuya Tsukagoshi, Thanh-Vinh Nguyen, Kayoko Hirayama-Shoji, Hidetoshi Takahashi, Kiyoshi Matsumoto and Isao Shimoyama

Journal of Physics D: Applied Physics (Institute of Physics Publishing) 51 ( 14 ) 145401 2018.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 00223727

Adhesive cells perceive the mechanical properties of the substrates to which they adhere, adjusting their cellular mechanical forces according to their biological characteristics. This mechanical interaction subsequently affects the growth, locomotion, and differentiation of the cell. However, little is known about the detailed mechanism that underlies this interaction between adherent cells and substrates because dynamically measuring mechanical phenomena is difficult. Here, we utilize microelectromechamical systems force sensors that can measure cellular traction forces with high temporal resolution (∼2.5 μs) over long periods (∼3 h). We found that the cellular dynamics reflected physical phenomena with time scales from milliseconds to hours, which contradicts the idea that cellular motion is slow. A single focal adhesion (FA) generates an average force of 7 nN, which disappears in ms via the action of trypsin-ethylenediaminetetraacetic acid. The force-changing rate obtained from our measurements suggests that the time required for an FA to decompose was nearly proportional to the force acting on the FA.

Access to Document (DOI)

　 Previous page - Next page 　