• Title/Summary/Keyword: electroactive

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Development of Braille Display Using Dielectric Elastomer (고분자 유전체를 이용한 시각 장애인용 점자 출력기 개발)

  • 이상원;구익모;정광목;이성일;최후곤;전재욱;남재도;최혁렬
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.11
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    • pp.961-970
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    • 2004
  • Tactile sensation is one of the most important sensory functions along with the auditory sensation for the visually impaired since it replaces the visual one of the persons with sight. In this paper, we present a tactile display device as a dynamic Braille display that is the unique tool f3r exchanging information among them. The tactile cell of the Braille display proposed is based on the dielectric elastomer, which is one of the electroactive polymers. It has advantageous features over the existing ones with respect to intrinsic softness, ease of fabrication, cost effectiveness and miniaturization. We introduce a new idea for actuation as well as additional considerations such as the driving circuit that makes it possible to drive multiple tactile cells in a high speed. Also, we describe the actuating mechanism of the Braille pin in details capable of realizing the enhanced spatial density of the tactile cells. Finally, results of psychophysical experiments are given to evaluate its effectiveness.

Improvement of Mechanical Properties of IPMC through Developing a Degree of Dispersion of SWCNT/Nafion Composite (SWCNT/Nafion 복합체의 분산능 향상을 통한 IPMC의 기계적 특성 향상)

  • Kwon, Hui-June;Kim, Ha-Na;Kang, Jung-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.5
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    • pp.131-136
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    • 2011
  • Many researchers are recently studying about Electroactive polymer(EAP). But it has a physical limitation, because of property of material. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. This study focuses on the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. To come up with mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we dispersed Single-walled carbon nanotubes(SWCNTs). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. We fabricated a disperse SWCNT/Nafion composite uniformly. Through the use of the E-beam evaporator to form an uniform electrode layer, we consummated the IPMC actuator. This result shows improving 1.5 times mechanical properties about driving force in IPMC.

Electrochemical Properties of Manganese Oxide coated onto Carbon Nanotubes for Energy Storage Applications (보조에너지원으로서의 수퍼커패시터용 나노전극소재로서의 탄소/망간산화물의 전기화학적 특성)

  • Ahn, Kyun-Young;Ma, Sang-Bok;Kim, Kwang-Bum
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.143-146
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    • 2007
  • Birnessite-type manganese dioxide($MnO_2$) was coated uniformly onto carbon nanotubes (CNTs) through a spontaneous direct redox reaction between CNTs and permanganate ions($MnO_4\;^-$). The initial specific capacitance of the $MnO_2/CNT$ nanocomposite in an organic electrolyte at a large current density of 1 A/g was 250 F/g, which is equivalent to 139 mAh/g based on the total weight of the electrode material including the electroactive material, conducting agent and binder. The specific capacitance of the $MnO_2$ in the $MnO_2/CNT$ nanocomposite was as high as 580 F/g (320 mAh/g), indicating excellent electrochemical utilization of the $MnO_2$. The addition of CNTs as a conducting agent can improve the high rate capability of $MnO_2/CNT$ nanocomposite considerably. An analysis of the in-situ X-ray absorption near-edge structure (XANES) showed an improvement in the structural and electrochemical reversibility of the $MnO_2/CNT$ nanocomposite by heat-treatment.

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Effect of Thermal Treatment on the Electrocatalytic Activities and Surface Roughness of ITO Electrodes

  • Choi, Moon-Jeong;Jo, Kyung-Mi;Yang, Hae-Sik
    • Journal of Electrochemical Science and Technology
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    • v.3 no.1
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    • pp.24-28
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    • 2012
  • The electrocatalytic activities and surface roughness of indium-tin-oxide (ITO) electrodes have been investigated after thermal treatment at 100, 150, or $200^{\circ}C$ for 30 min, 2 h, or 8 h. To check electrocatalytic activities, the electrochemical behavior of four electroactive species (p-hydroquinone, $Ru(NH_3){_6}^{3+}$, ferrocenemethanol, and $Fe(CN){_6}^{4-}$) has been measured. The electron transfer rate for p-hydroquinone oxidation and ferrocenemethanol oxidation increases with increasing the incubation temperature and the incubation period of time, but the rate for $Ru(NH_3){_6}^{3+}$ is similar irrespective of the incubation temperature and period because $Ru(NH_3){_6}^{3+}$ undergoes a fast outer-sphere reaction. Overall, the electrocatalytic activities of ITO electrodes increase with increasing the incubation temperature and period. The surface roughness of ITO electrodes increases with increasing the incubation temperature, and the thermal treatment generates many towering pillars as high as several tens of nanometer.

Electro-Active-Paper Actuator Made with LiCl/Cellulose Films: Effect of LiCl Content

  • Wang, Nian-Gui;Kim, Jae-Hwan;Chen, Yi;Yun, Sung-Ryul;Lee, Sun-Kon
    • Macromolecular Research
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    • v.14 no.6
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    • pp.624-629
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    • 2006
  • The cellulose-based, Electroactive Paper (EAPap) has recently been reported as a smart material with the advantages of lightweight, dry condition, biodegradability, sustainability, large displacement output and low actuation voltage. However, it requires high humidity.. This paper introduces an EAPap made with a cellulose solution and lithium chloride (LiCl), which can be actuated in room humidity condition. The fabrication process, performance test and effect of LiCl content of the EAPap actuator are illustrated. The bending displacement of the EAPap actuators was evaluated with actuation voltage, frequency, humidity and LiCl content changes. At a LiCl/ cellulose content of 3:10, the displacement output was maximized at a room humidity condition. Even though the displacement output was less than that of a high humidity EAPap actuator, the mechanical power output was not reduced due to the increased resonance frequency, which is promising for developing EAPap actuators that are less sensitive to humidity.

A study on the Spinel phase cathode materials with high capacity for lithium secondary batteries (리튬 2차 전지용 고용량 스피넬계 양극물질 연구)

  • Hong, Ki-Joo;Sun, Yang-Kook
    • Proceedings of the KIEE Conference
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    • 2001.11b
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    • pp.106-108
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    • 2001
  • As 3V cathode material, a new doping spinel material, LiMn1.6Se0.4O4 powder with a phase-pure polycrystalline was synthesized by a sol-gel method. In spite of Jahn-teller distortion in 3V region($2.4{\sim}3.5V$), the LiMn1.6Se0.4O4 electrode shows no capacity loss. The material in the 3V region initially delivers a discharge capacity of 100mAh/g which increase with cycling to reach 105mAh/g after 90cycles. And 5V cathode material LiNi0.5-xMxMn1.5O4(M=Cr, V, Fe) compounds have been synthesized by sol-gel method. a series of electroactive spinel compounds, LiNi0.5-xMxMn1.5O4(M=Cr, V, Fe) has been studied by crystallographic and electrochemical methods. The material presents only one plateau at around 4.5 V vs. Li/Li+ with a large discharge capacity of 152mAh/g and fairly good cyclability.

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Application of Polyaniline to an Enzyme-Amplified Electrochemical Immunosensor as an Electroactive Report Molecule

  • Kwon, Seong-Jung;Seo, Myung-Eun;Yang, Hae-Sik;Kim, Sang-Youl;Kwak, Ju-Hyoun
    • Bulletin of the Korean Chemical Society
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    • v.31 no.11
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    • pp.3103-3108
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    • 2010
  • Conducting polymers (CPs) are widely used as matrixes for the entrapment of enzymes in analytical chemistry and biosensing devices. However, enzyme-catalyzed polymerization of CPs is rarely used for immunosensing due to the difficulties involved in the quantitative analysis of colloidal CPs in solution phase. In this study, an enzyme-amplified electrocatalytic immunosensor employing a CP as a redox marker has been developed. A polyanionic polymer matrix, $\alpha$-amino-$\omega$-thiol terminated poly(acrylic acid), was employed for precipitation of CP. The acrylic acid group acts as a polyanionic template. The thiol terminus of the polymer was used to produce self-assembled monolayers (SAMs) on Au electrodes and the amine terminus was employed for immobilization of biomolecules. In an enzymeamplified sandwich type immunosensor, the polyaniline (PANI) produced enzymatically is attracted by the electrostatic force of the matrix polymer. The precipitated PANI was characterized by electrochemical methods.

Intergranular Corrosion of Stainless Steel (스테인리스강 입계부식)

  • Kim, Hong Pyo;Kim, Dong Jin
    • Corrosion Science and Technology
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    • v.17 no.4
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    • pp.183-192
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    • 2018
  • Stainless steel can be classified into three categories depending on the microstructure as austenitic stainless steel, ferritic stainless steel and martensitic stainless steel. Generally, stainless steel is extremely resistant to corrosion as the name implies. However, under specific environments, susceptibility to localized corrosion such as pitting, intergranular corrosion and stress corrosion cracking increases. This paper reviewed the state of arts on intergranular corrosion mechanisms, countermeasures on intergranular corrosion and intergranular corrosion test methods. Intergranular corrosion is mostly related with chromium depletion at the grain boundary and sometimes with segregation of electroactive elements in solution annealed stainless steel. Countermeasures on intergranular corrosion include avoiding chromium depletion by heat treatment and the addition of alloying elements. Sensitization evaluation of stainless steel was performed either through acid immersion test or electrochemical test. The methods were standardized in (Japanese Industrial Standards). Even though are useful in evaluating the degree of sensitization for industrial purpose but do not provide detailed information about sensitization mechanism, cause and chromium profile.

Electroactive Polymer Actuator for Lens-Drive Unit in Auto-Focus Compact Camera Module

  • Lee, Hyung-Kun;Choi, Nak-Jin;Jung, Sun-Kyung;Park, Kang-Ho;Jung, He-Won;Shim, Jae-Kyu;Ryu, Jae-Wook;Kim, Jong-Dae
    • ETRI Journal
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    • v.31 no.6
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    • pp.695-702
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    • 2009
  • We propose a lens-drive unit composed of an ionic polymer-metal composite (IPMC) for an auto-focus compact camera module in cellular phones to solve the power consumption problem of voice coil motors which are widely used in commercial products. In this research, an IPMC incorporated into a lens-drive unit is designed to implement a large displacement in low-power consumption by using an anisotropic plasma treatment. Experimental results show that a camera module containing IPMCs can control and maintain the position of the lens by using proportional integral derivative control with a photo-reflective position sensor despite the non-linear actuation behavior of IPMCs. We demonstrate that the fabrication and commercialization of a lens actuator that has a large displacement and low power consumption using IPMCs is possible in the near future.

Supercapacitive Properties of Polyaniline Electrode Electrodeposited on Carbon Nanotube/Acetonitrile-Butadiene Rubber as a Flexible Current Collector

  • Park, Jee-Hye;Kim, Sang-Hern;Ko, Jang-Myoun;Lee, Young-Gi;Kim, Kwang-Man
    • Journal of Electrochemical Science and Technology
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    • v.2 no.4
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    • pp.211-215
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    • 2011
  • Flexible sheets consisting of acrylonitrile-butadiene rubber (NBR) and carbon nanotube (CNT) are newly prepared varying the composition (CNT 20-25 wt.%) for use as a current collector of supercapacitor electrodes. The as-prepared CNT/NBR is electrodeposited with aniline using potentiodynamic cyclic voltammetry to yield a polyaniline (PANI)/CNT/NBR composite electrode. It is confirmed that the electrical conductivity of CNT/NBR current collector can be enhanced as the content of CNT increases. Cyclic voltammetry result shows that the sample of PANI/CNT(25 wt.%)/NBR composite achieves a maximum specific capacitance ($134.9\;F\;g^{-1}$) at $5\;mV\;s^{-1}$. Such supercapacitor application is possibly originated from the synergistic effects consisting of higher polarity of nitrile groups in NBR, conducting pathway of CNT, and electroactive property of PANI.