Details of a Researcher - Takahashi, Hidetoshi

Papers - Takahashi, Hidetoshi

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Gas sensor

I Shimoyama, K Matsumoto, Y Takei, H Takahashi, N Kiga, M Honda

US Patent 9,250,210 2016

Measurement of jumping force of a fruit fly using a mesa structured force plate

R Furuya, H Takahashi, NT Vinh, T Yano, K Ito, T Takahata, K Matsumoto, ...

2016 IEEE 29th International Conference on Micro Electro Mechanical Systems … (Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)) 2016-February 165 - 168 2016

ISSN 9781509019731

© 2016 IEEE. This paper reports on a mesa structured force plate for measurement of jumping force of a fruit fly. The proposed force plate is 5 mm × 5 mm × 20 μm in size. The thickness of the sensing beams is 7.5 μm which is thinner than that of the plate to increase the sensitivity in response to normal force. Using the fabricated force plate, the jumping force of a fruit fly was measured when it took off from the plate surface. The measurement result shows that the maximum value of the jumping force is approximately 8 times larger than the weight (mG, where m and G are the fruit fly mass and gravitational acceleration) of a fruit fly.

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Quantitative correlation between cardiac MIBG uptake and remaining axons in the cardiac sympathetic nerve in Lewy body disease

Takahashi M., Ikemura M., Oka T., Uchihara T., Wakabayashi K., Kakita A., Takahashi H., Yoshida M., Toru S., Kobayashi T., Orimo S.

Journal of Neurology, Neurosurgery and Psychiatry (Journal of Neurology, Neurosurgery and Psychiatry) 86 ( 9 ) 939 - 944 2015.09

ISSN 00223050

Objectives Reduced cardiac meta-iodobenzylguanidine (MIBG) uptake and loss of cardiac sympathetic axons, as its possible anatomical substrate, were both recognised in Lewy body disease (LBD), while their direct correlation has so far remained speculative. Increasing availability of autopsy-confirmed cases of LBD prompted us to quantify residual cardiac sympathetic axons to establish their relationship to cardiac MIBG uptake. Methods We collected cardiac tissue samples from 23 patients with autopsy-confirmed LBD and two non-LBD control patients who underwent 123 I-MIBG cardiac scintigraphy in life. Samples of the left ventricular anterior wall were stained with anti-tyrosine hydroxylase (TH) and anti-neurofilament (NF) antibodies as markers of cardiac nerve axons. We quantified the immunolabelled areas and assessed their correlation to standardised heart to mediastinum (H/M) ratios of 123 I-MIBG cardiac scintigraphy. Results Cardiac MIBG uptake in the early and delayed phases was reduced in 90.9% and 95.7% of patients with LBD, respectively. The area of TH-immunoreactive axons correlated significantly with the H/M ratio in the early (p=0.036) as well as in the delayed (p=0.018) phases. The area of NF-immunoreactive axons also correlated with the H/M ratio in the early (p=0.003) as well as in the delayed (p=0.001) phases. Conclusions Tight quantitative correlation between cardiac 123 I-MIBG uptake and corresponding loss of sympathetic axons in LBD, as established for the first time by this study, provides a scientific basis to confirm the reliability of MIBG cardiac scintigraphy as a powerful clinical tool to detect loss of these axons as a biomarker for the presence of Lewy body disease.

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Analysis of MEMS Spiral Metamaterial in the THz frequency

Kan Tetsuo, Isozaki Akihiro, Kanda Natsuki, Nemoto Natsuki, Konishi Kuniaki, Kuwata-Gonokami Makoto, Matsumoto Kiyoshi, Shimoyama Isao

JSAP Annual Meetings Extended Abstracts (The Japan Society of Applied Physics) 2015.1 862 - 862 2015.02

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Microneedle array fabrication using inclined/rotated uv lithography

Heo Y., Arakawa N., Yoshizawa S., Takahashi H., Kawano R.

MicroTAS 2015 - 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS 2015 - 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences) 1442 - 1444 2015

ISSN 9780979806483

Insects have hairy eyes that reduce particle deposition

GJ Amador, F Durand, W Mao, S Pusulri, H Takahashi, VT Nguyen, ...

The European Physical Journal Special Topics 224 (17-18), 3361-3377 (SPRINGER HEIDELBERG) 224 ( 17-18 ) 3361 - 3377 2015

Research paper (scientific journal), Joint Work, Accepted, ISSN 19516355

An insect's eyes may make up to 40% of its body's surface, and are in danger of being coated by foreign particles such as dust and pollen. To protect them, several insect species possess an array of ocular hairs evenly spaced between each photoreceptor unit. Although these hairs have been observed for over 50 years, their purpose remains a mystery. In this study, we elucidate the function of ocular hairs using a combination of experiments, numerical simulation and micro-fabrication. We measure the eyes of 18 species of insects and find that the length of their ocular hairs is equal to their spacing. We conduct wind tunnel experiments using both an insect eye mimic and an at-scale fabricated micro-pillar array of the same dimensions as the insect eye. Our experiments and simulations show that ocular hairs reduce airflow at the eye surface by up to 90%. We conclude that ocular hairs act similarly to mammalian eyelashes: as insects fly, ocular hairs deflect incoming air and create a zone of stagnant air. Airflow and particle deposition are reduced dramatically, while light is only minimally occluded. Micro-scale ocular hairs may find application in the deployment of sensors outdoors, for which accumulation of airborne dust and pollen has no current solution.

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Differential pressure sensor

I Shimoyama, K Matsumoto, T Takahata, KAN Tetsuo, K Kuwana, ...

US Patent 9,188,497 2015

Airflow shear stress sensor using side-wall doped piezoresistive plate

R Kazama, H Takahashi, T Takahata, K Matsumoto, I Shimoyama

2015 28th IEEE International Conference on Micro Electro Mechanical Systems … (IEEE) 2015-February ( February ) 710 - 713 2015

ISSN 10846999

This paper reports on a shear stress sensor for airflow. The sensor consists of a plate, side-wall doped beams and surrounding membrane with narrow gaps. The sensor plate was 300 mu mx350 mu mx3 um in size. The plate was supported by the side-wall doped beams, which can detect their horizontal deformation. The sensor structure was designed not to disturb target airflow circumstance owing to its flat surface. The fabricated sensor was able to measure shear stress of laminar airflow with the resolution under 1.0 Pa.

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A cantilever with comb structure modeled by a bristled wing of thrips for slight air leak

H Takahashi, A Isozaki, K Matsumoto, I Shimoyama

2015 28th IEEE International Conference on Micro Electro Mechanical Systems … (IEEE) 2015-February ( February ) 706 - 709 2015

ISSN 10846999

This paper reports a cantilever with comb structure, inspired by a bristled wing of thrips which acts as a continuous membrane wing because of the effects of low Reynolds numbers. The comb structures are formed at the edges of the cantilever and its surrounding frame. When differential pressure is applied to the cantilever, both comb structures act as airflow suppression through the gap. The leakage of the fabricated comb cantilever was smaller than the normal cantilever due to the overlapping area of the combs, even the gap area was twice larger. The proposed structure will be utilized as a high sensitive barometric pressure change detector.

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6-Axis force/torque sensor for spike pins of sports shoes

H Ishido, H Takahashi, A Nakai, T Takahata, K Matsumoto, I Shimoyama

2015 28th IEEE International Conference on Micro Electro Mechanical Systems … (IEEE) 2015-February ( February ) 257 - 260 2015

ISSN 10846999

This paper reports on a method to measure forces and torques acting on spike pins of sports shoes. We fabricated a 2 mm x 2 mm x 0.3 mm 6-axis force/torque sensor chip, which consists of 6 piezoresistive beams. From the resistance changes of the 6 beams, 6 components of forces and torques can be detected. The sensor chip was connected to a flexible printed circuit board (PCB) and covered with thin polydimethylsiloxane (PDMS). Then, the sensor chip and flexible PCB were embedded in spike-pin-shaped epoxy resin. We calibrated the spike-pin-shaped sensor, and confirmed that 6-axis forces and torques were able to be detected by the proposed sensor.

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3D structural foramation utilizing glass transition of a Parylene film

T Kan, A Isozaki, H Takahashi, K Matsumoto, I Shimoyama

2015 28th IEEE International Conference on Micro Electro Mechanical Systems … (IEEE) 2015-February ( February ) 405 - 408 2015

ISSN 10846999

This paper reports on a fabrication method of three-dimensional micro structures supported by a Parylene thin film. The three-dimensional structure formation procedure starts with an out-of-plane actuation of the Si surface micromachined structure coated with a thin Parylene film. At the same time of the actuation, the environmental temperature was elevated above the glass transition temperature T-g of the Parylene, 80-100 degrees C, and then cooled down below T-g. In this process, the rearrangement of the Parylene film happens above T-g, and the consolidated Parylene after the cooling down maintains three-dimensional micro structures as actuated. In a proof-of-principle experiment, the three-dimensional spiral structures formed by 300-nm-thick silicon were fixed by 1-mu m-thick Parylene film.

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Viscosity measurement based on the tapping-induced free vibration of sessile droplets using MEMS-based piezoresistive cantilevers

TV Nguyen, MD Nguyen, H Takahashi, K Matsumoto, I Shimoyama

Lab on a Chip 15 (18), 3670-3676 (ROYAL SOC CHEMISTRY) 15 ( 18 ) 3670 - 3676 2015

Joint Work, Accepted, ISSN 14730197

We report a simple technique to measure the free vibration of microlitre-sized droplets using an array of thirteen MEMS-based piezoresistive cantilevers and demonstrate its application for the measurement of viscosity. Because the damping of the free vibration of a liquid droplet is known to be affected by the viscosity of the liquid, measuring the vibration of a droplet allows the viscosity to be estimated from a dilute sample volume. However, conventional methods to measure the droplet vibration require sophisticated apparatuses, which hinder the development of a portable viscometer. Here, we show that MEMS-based piezoresistive cantilevers can be an excellent tool to measure the vibration of a sessile droplet due to the high sensitivity and simplicity of the readout scheme. Using the cantilever array, we analyse the normal force distribution on the contact area of a sessile droplet in the static state and during the vibration. Next, we show that the viscosity (from similar to 1-30 mPa s) can be estimated within an error of less than 10% from the attenuation rate of the cantilever output during the tapping-induced vibration of small droplets (similar to 2.4 mu L). In addition to the advantage of the small sample volume, the proposed viscometer has simple operation and readout schemes, which are desirable for many applications, including point-of-care testing and drug development.

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Two-axis MEMS-based force sensor for measuring the interaction forces during the sliding of a droplet on a micropillar array

N Thanh-Vinh, H Takahashi, K Matsumoto, I Shimoyama

Sensors and Actuators A: Physical 231, 35-43 (ELSEVIER SCIENCE SA) 231 35 - 43 2015

Joint Work, Accepted, ISSN 09244247

In this paper, we proposed a 2-axis MEMS-based force sensor to directly measure the interaction forces during the sliding of a water droplet on a superhydrophobic surface with a micropillar array. In our sensor design, a 300-nm-thick silicon (Si) structure was fabricated beneath a single micrometer-sized pillar as the sensing element. Two piezoresistors were formed at the root of two opposite Si beams to detect the forces acting on the pillar surface in the normal and shear directions. The proposed sensor has a sensing resolution of less than 20 nN for both normal and shear forces. This resolution is confirmed to be sufficient to measure the forces of a droplet acting on a micropillar. The fabricated sensor was demonstrated to be able to measure the interaction forces during the sliding of a 7.5 mu L water droplet on the micropillar array. (C) 2014 Elsevier B.V. All rights reserved.

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Quad-axial piezoresistive force sensor probe by four sensing elements with sidewall doping method

H Takahashi, S Hirakawa, T Takahata, K Matsumoto, I Shimoyama

2015 Transducers-2015 18th International Conference on Solid-State Sensors … (2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015) 1089 - 1092 2015

ISSN 9781479989553

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Out-of-plane actuation with a sub-micron initial gap for reconfigurable terahertz micro-electro-mechanical systems metamaterials

A Isozaki, T Kan, H Takahashi, K Matsumoto, I Shimoyama

Optics express 23 (20), 26243-26251 (OPTICAL SOC AMER) 23 ( 20 ) 26243 - 26251 2015

Joint Work, Accepted, ISSN 1094-4087

We propose a reconfigurable terahertz (THz) metamaterial that can control the transmittance by out-of-plane actuation with changing the sub-micron gap distance between electrically coupled metamaterial elements. By using the out-of-plane actuation, it was possible to avoid contact between the coupled metamaterial elements across the small initial gap during the adjustment of the gap size. THz spectroscopy was performed during actuation, and the transmission dip frequency was confirmed to be tunable from 0.82 to 0.92 THz for one linear polarization state and from 0.80 to 0.91 THz for the other linear polarization; the two polarizations were orthogonal. The proposed approach will contribute to the development of tunable metamaterials based on structural deformations. (C) 2015 Optical Society of America

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Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals

T Kan, A Isozaki, N Kanda, N Nemoto, K Konishi, H Takahashi, ...

Nature communications 6, 8422 (NATURE PUBLISHING GROUP) 6 8422 2015

Joint Work, Accepted, ISSN 2041-1723

Active modulation of the polarization states of terahertz light is indispensable for polarization-sensitive spectroscopy, having important applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. In the terahertz region, the lack of a polarization modulator similar to a photoelastic modulator in the visible range hampers expansion of such spectroscopy. A terahertz chiral metamaterial has a huge optical activity unavailable in nature; nevertheless, its modulation is still challenging. Here we demonstrate a handedness-switchable chiral metamaterial for polarization modulation employing vertically deformable Micro Electro Mechanical Systems. Vertical deformation of a planar spiral by a pneumatic force creates a three-dimensional spiral. Enantiomeric switching is realized by selecting the deformation direction, where the polarity of the optical activity is altered while maintaining the spectral shape. A polarization rotation as high as 28 degrees is experimentally observed, thus providing a practical and compact polarization modulator for the terahertz range.

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Characteristic evaluation of a bristled wing using mechanical models of a thrips wings with MEMS piezoresistive cantilevers

H TAKAHASHI, K SATO, MD NGUYEN, K MATSUMOTO, I SHIMOYAMA

Journal of Biomechanical Science and Engineering 10 (2), 14-00233-14-00233 (Japan Society of Mechanical Engineers) 10 ( 2 ) 1 - 10 2015

Joint Work, Accepted, ISSN 18809863

This paper discusses similar-scale mechanical models of a thrips wing using microelectromechanical systems (MEMS) piezoresistive cantilevers to quantitatively evaluate bristled wing characteristics. Each cantilever had combs with varying widths and neighboring gaps that were adjusted so that a constant surface area was maintained. The cantilever body was 1,324 × 256 × 5 μm&lt
sup&gt
3&lt
/sup&gt
in size. An aerodynamic drag force from the airflow applied to the cantilever surface was measured using the fractional resistance change of the piezoresistor due to the cantilever's deformation. The aerodynamic characteristics of each model were evaluated in a wind tunnel with airflow velocities between 1.2 and 5.6 m/s. The experimental results suggest that at a lower comb-width-based Reynolds number that was approximately equal to that of a bristled wing of a thrips, the comb areas of the cantilever act as an airflow suppression due to boundary layer effects, which results in an increased aerodynamic force.

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Fusion of cantilever and diaphragm pressure sensors according to frequency characteristics

R Watanabe, N Minh-Dung, H Takahashi, T Takahata, K Matsumoto, ...

2015 28th IEEE International Conference on Micro Electro Mechanical Systems … (IEEE) 2015-February ( February ) 212 - 214 2015

ISSN 10846999

This paper reports on an approach to measure sensitive barometric pressure by fusing a cantilever-based differential pressure sensor (DPS) and a commercially available diaphragm-based absolute pressure sensor (APS). At high frequency, the DPS can detect smaller pressure change than the APS. At low frequency, the APS shows less drift absolute pressure than the DPS. By utilizing the DPS and APS at each advantageous frequency, we propose a highly sensitive and drift-free measurement of barometric pressure.

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MEMS Force Sensor for Study of Droplet Sliding

TV NGUYEN, H TAKAHASHI, K MATSUMOTO, I SHIMOYAMA

電気学会フィジカルセンサ研究会資料, 47-51 PHS-15 ( 31-43 ) 47 - 51 2015

Parallel Helmholtz resonators for a planar acoustic notch filter

A Isozaki, H Takahashi, H Tamura, T Takahata, K Matsumoto, ...

Applied Physics Letters 105 (24), 241907 (AMER INST PHYSICS) 105 ( 24 ) 241907 2014

Joint Work, Accepted, ISSN 00036951

This paper reports on an acoustic planar notch filter with a sub-wavelength thickness at the notch frequency. The developed notch filter consists of a number of spherical Helmholtz resonators (HRs) connected to a hole created in a plate. The HRs were placed at the in-plane vertices of a regular polygon. A simulated pressure distribution revealed that this uniform arrangement of HRs improves the silencing effect because the uniform applied waves emitted from the HRs act as canceling waves to the cross-section of the short hole (in this case, the length of the hole is sub-wavelength). The total pressure emitted from the HRs is equal regardless of the number of HRs connected to the hole. Therefore, the arrangement of HRs is essential for realizing a planar notch filter. Simulated transmittance spectra showed that the depth of the dip in the transmittance increased with the number of uniformly arranged HRs. We confirmed that the experimental transmittance spectra of fabricated notch filters, which consisted of between one and six HRs, agreed with the simulated transmittance spectra. The design of the acoustic filter presented in this study and the corresponding analysis should motivate further development of thin acoustic filters. (C) 2014 AIP Publishing LLC.

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