• 제목/요약/키워드: Electrochemical system

검색결과 944건 처리시간 0.026초

Electrical Recognition of Label-Free Oligonucleotides upon Streptavidin-Modified Electrode Surfaces

  • Park, Jong-Wan;Jung, Ho-Sub;Lee, Hea-Yeon;Kawai, Tomoji
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제10권6호
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    • pp.505-509
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    • 2005
  • For the purpose of developing a direct label-free electrochemical detection system, we have systematically investigated the electrochemical signatures of each step in the preparation procedure, from a bare gold electrode to the hybridization of label-free complementary DNA, for the streptavidin-modified electrode. For the purpose of this investigation, we obtained the following pertinent data; cyclic voltammogram measurements, electrochemical impedance spectra and square wave voltammogram measurements, in $Fe(CN)_6^{3-}/Fe(CN)_6^{4-}$ solution (which was utilized as the electron transfer redox mediator). The oligonucleotide molecules on the streptavidin-modified electrodes exhibited intrinsic redox activity in the ferrocyanide-mediated electrochemical measurements. Furthermore, the investigation of electrochemical electron transfer, according to the sequence of oligonucleotide molecules, was also undertaken. This work demonstrates that direct label-free oligonucleotide electrical recognition, based on biofunctional streptavidin-modified gold electrodes, could lead to the development of a new biosensor protocol for the expansion of rapid, cost-effective detection systems.

Modeling and Applications of Electrochemical Impedance Spectroscopy (EIS) for Lithium-ion Batteries

  • Choi, Woosung;Shin, Heon-Cheol;Kim, Ji Man;Choi, Jae-Young;Yoon, Won-Sub
    • Journal of Electrochemical Science and Technology
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    • 제11권1호
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    • pp.1-13
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    • 2020
  • As research on secondary batteries becomes important, interest in analytical methods to examine the condition of secondary batteries is also increasing. Among these methods, the electrochemical impedance spectroscopy (EIS) method is one of the most attractive diagnostic techniques due to its convenience, quickness, accuracy, and low cost. However, since the obtained spectra are complicated signals representing several impedance elements, it is necessary to understand the whole electrochemical environment for a meaningful analysis. Based on the understanding of the whole system, the circuit elements constituting the cell can be obtained through construction of a physically sound circuit model. Therefore, this mini-review will explain how to construct a physically sound circuit model according to the characteristics of the battery cell system and then introduce the relationship between the obtained resistances of the bulk (Rb), charge transfer reaction (Rct), interface layer (RSEI), diffusion process (W) and battery characteristics, such as the state of charge (SOC), temperature, and state of health (SOH).

A Study on the Electrochemical Characteristics of Al-Si Casting Alloys in NaCl Solution (NaCl 수용액에서 Al-Si계 주조용 합금의 전기화학적 특성 연구)

  • Woo, Sang-Hyun;Son, Young-Jin;Lee, Byung-Woo
    • Journal of Power System Engineering
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    • 제18권6호
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    • pp.29-33
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    • 2014
  • The electrochemical characteristics of Al-Si casting alloys (Al-10%Si, Al-9%Si, Al-7%Si) in 3.5% NaCl solution at room temperature was studied using potentiodynamic techniques. The electrochemical values of corrosion potential($E_c$), corrosion current density($I_c$) and corrosion rate(mpy) were examined. The Al-Si alloys had several compounds such as $Mg_2Si$, ${\pi}$-$Al_8Si_6Mg_2Fe$ and $Al_2CuMg$ which could affect corrosion resistance significantly. The potentiodynamic polarization curve exhibited typical active behavior in anodic polarization curve. The major corrosion mechansim for the Al-Si alloys were pitting and grain boundary corrosion. As increasing Si and Cu contents, their corrosion resistance was decreased.

The influence of impedance on micro electrochemical machining (마이크로 전해가공에서 임피던스의 영향)

  • 강성일;주종길;박규열;전종업
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.1893-1896
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    • 2003
  • This research aimed to fabricate a micro structure using micro electrochemical machining (${\mu}$-ECM). with a view to that the theory of ${\mu}$-ECM is established accurately in a different way of conventional electrochemical machining. In details, if the impedance is existed in the system, it is difficult to analyze the micro electrochemical reaction efficiently in polarization curve using a potentiodynamic test. Hence, this research investigates the relationships between impedance and electric current measuring with a potentiostatic test applying to a pair or electrode as a constant potential. And this paper examines the influence of temperature of electrolyte on polarization curve for the quantitative analysis of electrochemical reactions.

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Effects of Applied Bias Conditions on Electrochemical Etch-stop Characteristics (인가 바이어스 조건이 전기화학적 식각정지 특성에 미치는 영향)

  • 정귀상;강경두;김태송;이원재;송재성
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제14권4호
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    • pp.263-268
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    • 2001
  • This paper describes the effects of applied bias conditions on electrochemical etch-stop characteristics. THere are a number of key issues such as diode leakage and ohmic losses which arise when applying the conventional 3-electrochemical etch-stop to fabricated some of he MEMS(microelectro mechanical system) and SOI(Si-on-insulator) structures which employ SDB(Si-wafer direct bonding). This work allows to perform anin situ diagnostic to predict whether or not an electrochemical etch-stop would fail due to diode-leakage-induced premature passivation. In addition, it presents technology which takes into account the effects of ohmic losses and allows to calculate the appropriate bias necessary to obtain a successful electrochemical etch-stop.

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Electrodeposition of GMR Ni/Cu Multilayers in a Recirculating Electrochemical Flow Reactor

  • Rheem, Young-Woo
    • Korean Journal of Materials Research
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    • 제20권2호
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    • pp.90-96
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    • 2010
  • The recirculating electrochemical flow reactor developed at UCLA has been employed to fabricate nanostructured GMR multilayers. For comparison, Ni/Cu multilayers have been electrodeposited from a single bath, from dual baths and from the recirculating electrochemical flow reactor. For a magnetic field of 1.5 kOe, higher GMR (Max. -5%) Ni/Cu multilayers with low electrical resistivity (< $10\;{\mu}{\Omega}{\cdot}cm$) were achieved by the electrochemical flow reactor system than by the dual bath (Max. GMR = -4.2% and < $20\;{\mu}{\Omega}{\cdot}cm$) or the single bath (Max. GMR = -2.1% and < $90\;{\mu}{\Omega}{\cdot}cm$) techniques. Higher GMR effects have been obtained by producing smoother, contiguous layers at lower current densities and by the elimination of oxide film formation by conducting deposition under an inert gas environment. Our preliminary GMR measurements of Ni/Cu multilayers from the electrochemical flow reactor obtained at low magnetic field of 0.15 T, which may approach or exceed the highest reported results (-7% GMR) at magnetic fields > 5 kOe.