• Title/Summary/Keyword: pH Sensor

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Control of tendon driven one-link manipulator

  • Choi, H.R.;Lee, Y.T.;Kim, J.H.;Chung, W.K.;Youm, Y.
    • 제어로봇시스템학회:학술대회논문집
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    • 1992.10b
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    • pp.290-295
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    • 1992
  • Tendon driven method to drive one joint using two actuators is developed and implemented. While the method has advantages over conventional transmissions, it also has several drawbacks like tendon slack, elongation and endurability. In this paper, a compensation method of the intrinsic non-linearities of tendon is proposed to improve the performance of antagonistic tendon driven method. In this method, tendon tension measurement is prerequisite which is measured with strain gauge type tension sensor. The developed method is implemented on one link test bed with colocated and non-colocated position sensor.

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Fabrication of Hydrogel and Gas Permeable Membranes for FET Type Dissolved $CO_{2}$ Sensor by Photolithographic Method (사진식각법을 이용한 FET형 용존 $CO_{2}$ 센서의 수화젤막 및 가스 투과막 제작)

  • Park, Lee-Soon;Kim, Sang-Tae;Koh, Kwang-Nak
    • Journal of Sensor Science and Technology
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    • v.6 no.3
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    • pp.207-213
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    • 1997
  • A field effect transistor(FET) type dissolved carbon dioxide($pCO_{2}$) sensor with a double layer structure of hydrogel membrane and $CO_{2}$ gas permeable membrane was fabricated by utilizing a $H^{+}$ ion selective field effect transistor(pH-ISFET) with Ag/AgCl reference electrode as a base chip. Formation of hydrogel membrane with photo-crosslinkable PVA-SbQ or PVP-PVAc/photosensitizer system was not suitable with the photolithographic process. Furthermore, hydrogel membrane on pH-ISFET base chip could be fabricated by photolithographic method with the aid of N,N,N',N'-tetramethyl othylenediarnine(TED) as $O_{2}$ quencher without using polyester film as a $O_{2}$ blanket during UV irradiation process. Photosensitive urethane acrylate type oligomer was used as gas permeable membrane on top of hydrogel layer. The FET type $pCO_{2}$ sensor fabricated by photolithographic method showed good linearity (linear calibration curve) in the range of $10^{-3}{\sim}10^{0}\;mol/{\ell}$ of dissolved $CO_{2}$ in aqueous solution with high sensitivity.

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Multifunctional Marine Exploration Robot for Fish Farm Management (양식장 관리를 위한 다기능 해양탐사 로봇)

  • Yeo, Sang-Sam;Park, Joo-Ryeoll;Lee, Dong-Kyu;Kim, Myeong-Gi;Yu, Ju-Young;Lee, Sang Hyeop
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2021.07a
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    • pp.489-490
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    • 2021
  • 본 연구에서는 해양사고 처리 중 발생하는 인명사고 발생률을 감소시키고, 효율적으로 양식장을 관리하는 것을 전제로 카메라와 센서를 다기능 해양탐사 로봇에 적용하고자 한다. 현재의 양식장 관리 시스템은 수온 체크만 할 수 있게 되어있다. 이러한 시스템은 양식어에게 적합한 환경을 제공해주기 쉽지 않다. 본 논문은 이러한 문제점들을 개선하기 위해 기존의 해양 처리시스템과 양식 시스템 대신 카메라와 수온 센서, pH 농도 센서, 초음파 거리 센서, DC 모터, 블루투스 모듈을 적용한 다기능 해양탐사 로봇 기술을 제안한다. 기존의 시스템과는 다르게 안전하고 효율적으로 환경을 분석하고, 제어할 수 있다.

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Low-Power Fully Digital Voltage Sensor using 32-nm FinFETs

  • Nguyen, H.V.;Kim, Youngmin
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.1
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    • pp.10-16
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    • 2016
  • In this paper, a design for a fully digital voltage sensor using a 32-nm fin-type field-effect transistor (FinFET) is presented. A new characteristic of the double gate p-type FinFET (p-FinFET) is examined and proven appropriate for sensing voltage variations. On the basis of this characteristic, a novel technique for designing low-power voltage-to-time converters is presented. Then, we develop a digital voltage sensor with a voltage range of 0.7 to 1.1V at a 50-mV resolution. The performance of the proposed sensor is evaluated under a range of voltages and process variations using Simulation Program with Integrated Circuit Emphasis (SPICE) simulations, and the sensor is proven capable of operating under ultra-low power consumption, high linearity, and fairly high-frequency conditions (i.e., 100 MHz).

Development of Assembly for Fast BOD Estimation and Its Applications (신속한 BOD 측정장치의 개발과 응용)

  • Soon, Moo-Jeong;Kim, Eun-Jeong;Jang, Seh-Yong;Hong, Daeil
    • Analytical Science and Technology
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    • v.7 no.3
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    • pp.285-291
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    • 1994
  • A microbial BOD sensor for the continuous estimation of BOD was been developed by immobilizing Trichosporon cutaneum, which was immobilized between a dialysis and a gas-permeable membrane, on an oxygen electrode. The optimum pH and temperature for BOD measurement using this sensor were pH 7.0 and $32{\sim}33^{\circ}C$, respectively. The best result was obtained at 2~3ml/min flow rate in 0.1M phosphate buffer solution. A linear relationship was observed between ${\Delta}DO$ and the concentration of standard GGA solution below 60mg/l(90ppm $BOD_5$). The reproducibility was found to be within 3% for the standard solution containing glucose 30mg/l and glutamic acid 30mg/l. The output DO value of this sensor was almost constant for 30 dalys. The response time and the recovery time were about 5 and 10 min, respectively. This sensor was employed for the BOD measurement of waste pollutants and was compared with $BOD_5$ method.

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NH3 Sensing Properties of SnO Thin Film Deposited by RF Magnetron Sputtering

  • Vu, Xuan Hien;Lee, Joon-Hyung;Kim, Jeong-Joo;Heo, Young-Woo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.272-272
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    • 2014
  • SnO thin films, 100 nm in thickness, were deposited on glass substrates by RF magnetron sputtering. A stack structure of $SnO_2/SnO$, where few nanometers of $SnO_2$ were determined on the SnO thin film by X-ray photoelectron spectroscopy. In addition, XPS depth profile analysis of the pristine and heat treated thin films were introduced. The electrical behavior of the as-sputtered films during the annealing was recorded to investigate the working conditions for the SnO sensor. Subsequently, The NH3 sensing properties of the SnO sensor at operating temperature of $50-200^{\circ}C$ were examined, in which the p-type semiconducting sensing properties of the thin film were noted. The sensor shows good sensitivity and repeatability to $NH_3$ vapor. The sensor properties toward several gases like $H_2S$, $CH_4$ and $C_3H_8$ were also introduced. Finally, a sensing mechanism was proposed and discussed.

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Study on Angular Rate Sensor using Sol-Gel PZT thin film (Sol-gel 압전체 박막을 이용한 각속도 센서에 대한 연구)

  • Lee, S. H.;R. Meada;M. Esashi
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.03a
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    • pp.34-34
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    • 2003
  • Piezoelectric or magnetostrictive materials, known as smart materials, have been researched widely for sensors or actuators in micro system technology. In our research, thick sol-gel lead zirconate titanate(Pb(Zr$\sub$1-x/Ti$\sub$x/)O$_3$) films were fabricated and their characteristics were investigated f3r angular rate sensor applications. The thickness of the PZT films is 1.5${\mu}$m, which is required by a vibration angular rate sensor for a good actuation and sensing. The remnant polarization of the PZT flms is 12.0 ${\mu}$C/$\textrm{cm}^2$. The electromechanical constants of PZT thin film showed the value of susceptance(B) of 4800${\mu}$ s at capacitance of 790pF. The PZT films were applied to the vibration angular rate sensor structure and the vibration of 1.78 ${\mu}$m in amplitude at the resonant frequency of 35.8㎑ was obtained by driving voltage of 5V$\sub$p-p/ of bulk piezoelectric materials with out of phase signal through voltage and inverting amplifier.

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Fabrication and Electrical Properties of Anodic Aluminum Oxide Membrane with Various Anodizing Temperatures for Biosensor (바이오센서로 응용을 위한 양극산화알루미늄의 양극산화 온도에 따른 제작 및 전기적 특성)

  • Yeo, Jin-Ho;Lee, Sung-Gap;Kim, Yong-Jun;Lee, Young-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.6
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    • pp.394-398
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    • 2014
  • We fabricated the electrolyte-dielectric-metal (EDM) sensor on the base of AAO (anodic aluminum oxide) template with variation of the anodizing temperature. When a surface is immersed or created in an aqueous solution, a discontinuity is formed at the interface where such physicochemical variables as electrical potential and electrolyte concentration change significantly from the aqueous phase to another phase. Because of the different chemical potentials between the two phases, charge separation often occurs at the interfacial region [1]. This interfacial region, togeter with the charged surface, is usually known as the electrical double layer (EDL) [2]. The structural and electrochemical properties of AAO sensor were investigated for applications in capacitive pH sensors. To change the thickness of the AAO template, the anodizing temperature was varied from $5^{\circ}C$ to $20^{\circ}C$, the thickness of the AAO template invreased from 300 nm to 477 nm. The pH sensitivity of sensors with the anodizing temperature of $20^{\circ}C$ showed the highest value of 56.4 mV/pH in the pH range of 3 to 11. The EDM sensor with the anodizing temperature of $20^{\circ}C$ exhibited the best long-term stability of 0.037 mV/h.

Impact of pH on the response of bovine serum albumin to gold surface plasmon resonance chip (소 혈청 알부민의 금 표면 플라즈몬 공명 칩과의 반응에 대한 pH의 영향)

  • Sohn, Young-Soo
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.326-330
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    • 2021
  • Reactions between gold (Au) surface plasmon resonance (SPR) chips and bovine serum albumin (BSA) dissolved in solutions of different pH were investigated. The charge on the BSA depends on the pH of the solution in which it is dissolved. Thus, dissolving BSA in different pH solutions resulted in different charges of BSA. Among the BSA dissolved in solutions with pH 4.01, 7.4, and 10.01, the SPR response was the highest for BSA dissolved in the solution of pH 4.01. To eliminate the response variation owing to the difference in the refractive indices of the solutions, phosphate buffered saline (PBS) was injected into the system after the reaction of BSA with the Au SPR chip had happened. In this case too, the BSA dissolved in the solution with pH 4.01 exhibited the highest response. This may be attributed to the non-uniform distribution of ionic patches on the BSA, which can induce electrostatic attraction to the surface even though BSA has a positive charge at pH 4.01, and the absolute values of the net charge of BSA at pH 4.01 and 7.4 were very close.

Redundant Sensor Signal Validation of Nuclear Power Plants Using the Simplified Parity Space Method (단순화된 패리티 공간기법을 이용한 원전 다중센서 신호검증)

  • Oh, S.H.;Kim, D.I.;Zoo, O.P.;Chung, Y.H.;Ryu, B.H.;Lim, C.H.;Kim, K.J.
    • Proceedings of the KIEE Conference
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    • 1993.11a
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    • pp.317-319
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    • 1993
  • The function estimation characteristics of neural networks can be used for sensor signal validation of a system. In case of applying the neural networks to signal validation, it is a important problem that the redundant sensor signals used as a input signal of neural networks should be validated. In this paper, we simplify the conventional parity space method in order to input the validated signal to the neural networks and also propose the sensor signal validation method, which estimates the reliable sensor output combining neural networks with the simplified parity space method. The acceptability of the proposed signal validation method is demonstrated by using the simulation data in safety injection accident of nuclear power plants.

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