• Title/Summary/Keyword: MEMS 센서

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Nanostructured Ni-Mn double hydroxide for high capacitance supercapacitor application

  • Pujari, Rahul B.;Lee, Dong-Weon
    • Journal of Sensor Science and Technology
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    • v.30 no.2
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    • pp.71-75
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    • 2021
  • Recently, transition-metal-based hydroxide materials have attracted significant attention in various electrochemical applications owing to their low cost, high stability, and versatility in composition and morphology. Among these applications, transition-metal-based hydroxides have exhibited significant potential in supercapacitors owing to their multiple redox states that can considerably enhance the supercapacitance performance. In this study, nanostructured Ni-Mn double hydroxide is directly grown on a conductive substrate using an electrodeposition method. Ni-Mn double hydroxide exhibits excellent electrochemical charge-storage properties in a 1 M KOH electrolyte, such as a specific capacitance of 1364 Fg-1 at a current density of 1 mAcm-2 and a capacitance retention of 94% over 3000 charge-discharge cycles at a current density of 10 mAcm-2. The present work demonstrates a scalable, time-saving, and cost-effective approach for the preparation of Ni-Mn double hydroxide with potential application in high-charge-storage kinetics, which can also be extended for other transition-metal-based double hydroxides.

마이크로 기술을 이용한 심장세포칩

  • Park, Jeong-Yeol
    • Journal of the KSME
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    • v.50 no.11
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    • pp.43-46
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    • 2010
  • 이글에서는 마이크로 기술, 특히 Microelectromechanical System(MEMS) 기술을 활용하여 심장세포의 기계적/물리적 특성 분석을 위한 심장세포용 바이오센서 및 심장세포의 기계적 힘을 이용한 심장세포 기반의 바이오 하이브리드(biohybrid) 디바이스에 대하여 소개하고자 한다.

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전자기 구동 마이크로 액츄에이터

  • 안종혁
    • 전기의세계
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    • v.42 no.11
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    • pp.23-29
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    • 1993
  • 최근에 마이크로 머신의 여러 연구분야중에서 Micro-Electro-Magnetic-Mechanical-System(MEMS)분야가 연구의 최대 관심사로 떠오르며, 완전집적 전자력 구동 액츄에이터와 센서의 개발, 실용 및 응용에 여러 세계적인 굴지의 연구소 및 회사가 속속 참여하고 있다는 것은 시사해주는 바가 크다.

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Implementation of a Helmet Azimuth Tracking System in the Vehicle (이동체 내의 헬멧 방위각 추적 시스템 구현)

  • Lee, Ji-Hoon;Chung, Hae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.4
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    • pp.529-535
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    • 2020
  • It is important to secure the driver's external field view in armored vehicles surrounded by iron armor for preparation for the enemy's firepower. For this purpose, a 360 degree rotatable surveillance camera is mounted on the vehicle. In this case, the key idea is to recognize the head of the driver wearing a helmet so that the external camera rotated in exactly the same direction. In this paper, we introduce a method that uses a MEMS-based AHRS sensor and a illuminance sensor to compensate for the disadvantages of the existing optical method and implements it with low cost. The key idea is to set the direction of the camera by using the difference between the Euler angles detected by two sensors mounted on the camera and the helmet, and to adjust the direction with illuminance sensor from time to time to remove the drift error of sensors. The implemented prototype will show the camera's direction matches exactly in driver's one.

Thermocompression bonding for wafer level hermetic packaging of RF-MEMS devices (RF-MEMS 소자의 웨이퍼 레벨 밀봉 패키징을 위한 열압축 본딩)

  • Park, Gil-Soo;Seo, Sang-Won;Choi, Woo-Beom;Kim, Jin-Sang;Nahm, Sahn;Lee, Jong-Heun;Ju, Byeong-Kwon
    • Journal of Sensor Science and Technology
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    • v.15 no.1
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    • pp.58-64
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    • 2006
  • In this study, we describe a low-temperature wafer-level thermocompression bonding using electroplated gold seal line and bonding pads by electroplating method for RF-MEMS devices. Silicon wafers, electroplated with gold (Au), were completely bonded at $320^{\circ}C$ for 30 min at a pressure of 2.5 MPa. The through-hole interconnection between the packaged devices and external terminal did not need metal filling process and was made by gold films deposited on the sidewall of the throughhole. This process was low-cost and short in duration. Helium leak rate, which is measured to evaluate the reliability of bonded wafers, was $2.7{\pm}0.614{\times}10^{-10}Pam^{3}/s$. The insertion loss of the CPW packaged was $-0.069{\sim}-0.085\;dB$. The difference of the insertion loss between the unpackaged and packaged CPW was less than -0.03. These values show very good RF characteristics of the packaging. Therefore, gold thermocompression bonding can be applied to high quality hermetic wafer level packaging of RF-MEMS devices.

반도체 MEMS 공정에 적용하기 위한 micro blaster 식각 특성

  • Kim, Dong-Hyeon;Gang, Tae-Uk;Kim, Sang-Won;Gong, Dae-Yeong;Seo, Chang-Taek;Kim, Bong-Hwan;Jo, Chan-Seop;Lee, Jong-Hyeon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.245-245
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    • 2010
  • 최근에 반도체 소자 및 마이크로머신, 바이오센서 등에 사용되는 미세 부품에 대한 연구 개발이 활발히 진행되고 있다. 미세 부품을 제작하기 위한 MEMS 공정은 대표적으로 화학용액을 이용한 습식식각, 플라즈마를 이용한 건식식각 등이 주를 이룬다. Micro blaster는 경도가 강하고 화학적 내성을 가지며 용융점이 높아 반도체 MEMS 공정에 어려움이 있는 기판을 다양한 형태로 식각 할 수 있는 기계적인 식각 공정 기술이라 할 수 있다. Micro blaster의 식각 공정은 고속의 날카로운 입자가 공작물을 타격할 때 입자의 아래에는 고압축응력이 발생하게 되고, 이 고압축 응력에 의하여 소성변형과 탄성변형이 발생된다. 이러한 변형이 발전되어 재료의 파괴 초기값보다 크게 되면 크랙이 발생되고, 점점 더 발전하게 되면 재료의 제거가 일어나는 단계로 이루어진다. 본 연구에서는 micro blaster 장비를 반도체 MEMS 공정에 적용하기 위한 식각 특성에 관하여 확인하였다. Micro blaster 장비와 식각에 사용한 파우더는 COMCO INC. 제품을 사용하였다. Micro blaster를 $Al_2O_3$ 파우더의 입자 크기, 분사 압력, 기판의 종류, 노즐과 기판과의 간격, 반복 횟수, 노즐 이동 속도 등의 공정 조건에 따른 식각 특성에 관하여 분석하였다. 특히 실제 반도체 MEMS 공정에 적용 가능한지 여부를 확인하기 위하여 바이오 PCR-chip을 제작하였다. 먼저 glass 기판과 Si wafer 기판에서의 식각률을 비교 분석하였고, 이 식각률을 바탕으로 바이오 PCR-chip에 사용하게 될 미세 홀과 미세 채널, 그리고 미세 챔버를 형성 하였다. 패턴을 형성하기 위하여 TOK Ordyl 사의 DFR(dry film photoresist:BF-410)을 passivation 막으로 사용하였다. Micro blaster에 사용되는 파우더의 직경이 수${\mu}m$ 이상이기 때문에 $10\;{\mu}m$ 이하의 미세 채널과 미세홀을 형성하기 어려웠지만 현재 반도체 MEMS 공정 기술로 제작 연구되어지고 있는 바이오 PCR-chip을 직접 제작하여 micro blaster를 이용한 반도체 MEMS 공정 기술에 적용 가능함을 확인하였다.

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Comparison Between Performance of Wireless MEMS Sensors and an ICP Sensor With Earthquake-Input Ground Motions (지진 입력 진동대를 이용한 무선 MEMS 센서와 ICP 가속도계의 성능 비교)

  • Mapungwana, S.T.;Lee, Jong-Ho;Yoon, Sung-Won
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.2
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    • pp.63-72
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    • 2019
  • Wireless sensors are more favorable in measuring structural response compared to conventional sensors in terms of them being easier to use with no issues with cables and them being considerably cheaper. Previous tests have been conducted to analyze the performance of MEMS (Micro Electro Mechanical Systems) sensor in sinusoidal excitation tests. This paper analyzes the performance of in-built MEMS sensors in devices by comparing with an ICP sensor as the reference. Earthquake input amplitude excitation in shaking table tests was done. Results show that MEMS sensors are more accurate in measuring higher input amplitude measurements which range from 100gal to 250gal than at lower input amplitudes which range from 10gal to 50gal. This confirms the results obtained in previous sinusoidal tests. It was also seen that natural frequency results have lower error values which range from 0% to 3.92% in comparison to the response spectra results. This also confirms that in-built MEMS sensors in mobile devices are good at estimating natural frequency of structures. In addition, it was also seen that earthquake input amplitudes with more frequency contents (Gyeongju) had considerably higher error values than Pohang excitation tests which has less frequency contents.

Image Georeferencing using AT without GCPs for a UAV-based Low-Cost Multisensor System (UAV 기반 저가 멀티센서시스템을 위한 무기준점 AT를 이용한 영상의 Georeferencing)

  • Choi, Kyoung-Ah;Lee, Im-Pyeong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.2
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    • pp.249-260
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    • 2009
  • The georeferencing accuracy of the sensory data acquired by an aerial monitoring system heavily depends on the performance of the GPS/IMU mounted on the system. The employment of a high performance but expensive GPS/IMU unit causes to increase the developmental cost of the overall system. In this study, we simulate the images and GPS/IMU data acquired by an UAV-based aerial monitoring system using an inexpensive integrated GPS/IMU of a MEMS type, and perform the image georeferencing by applying the aerial triangulation to the simulated sensory data without any GCP. The image georeferencing results are then analyzed to assess the accuracy of the estimated exterior orientation parameters of the images and ground points coordinates. The analysis indicates that the RMSEs of the exterior orientation parameters and ground point coordinates is significantly decreased by about 90% in comparison with those resulted from the direct georeferencing without the aerial triangulation. From this study, we confirmed the high possibility to develop a low-cost real-time aerial monitoring system.