• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.2
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• pp.92-97
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• 2002

One of the important roles of a DNA chip is the capability of detecting genetic diseases and mutations by analyzing DNA sequence. For a successful electrochemical genotyping, several aspects should be considered including the chemical treatment of electrode surface, DNA immobilization on electrode, hybridization, choice of an intercalator to be selectively bound to double standee DNA, and an equipment for detecting and analyzing the output signal. Au was used as the electrode material, 2-mercaptoethanol was used for linking DNA to Au electrode, and methylene blue was used as an indicator that can be bound to a double stranded DNA selectively. From the analysis of reductive current of this indicator that was bound to a double stranded DNA on an electrode, a normal double stranded DNA was able to be distinguished from a single stranded DNA in just a few seconds. Also, it was found that the peak reduction current of indicator is proportional to the concentration of target DNA to be hybridized with probe DNA. Therefore, it is possible to realize a sim71e and cheats DNA sensor using the electrochemical measurement for genotyping.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.615-619
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• 2018

To produce carbon electrodes for use in perovskite solar cells, electrode samples are prepared by mixing various weight ratios of 35 nm nano carbon(NC) and $1{\mu}m$ graphite flakes(GF), GF/(NC+GF) = 0, 0.5, 0.7, and 1, in chlorobenzene(CB) solvent with a $ZrO_2$ binder. The carbon electrodes are fabricated as glass/FTO/carbon electrode devices for microstructure characterization using transmission electron microscopy, optical microscopy, and a field emission scanning electron microscopy. The electrical characterization is performed with a four-point probe and a multi tester. The microstructure characterization shows that an electrode with excellent attachment to the substrate and no surface cracks at weight ratios above 0.5. The electrical characterization results show that the sheet resistance is <$70{\Omega}/sq$ and the interface resistance is <$70{\Omega}$ at weight ratios of 0.5 and 0.7. Therefore, a carbon paste electrode with microstructure and electrical properties similar to those of commercial carbon electrodes is proposed with an appropriate mixing ratio of NC and GF containing a CB solvent and $ZrO_2$.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.900-902
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• 1992

In order to develope the uniform Plasma source which is able to make polymer or glass surface modification, the d.c glow discharge characteristics for the hemisphere -cylindrical electrode system with external d.c magnetic field are investigated. Single probe method has been used for detecting plasma parameters. We make uniform plasma generated to the external of electrode between hemisphere and cylindrical electrode. The surface treatment of metal and insulate has been performed by this uniform plasma.

• Journal of Electrochemical Science and Technology
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• v.7 no.4
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• pp.286-292
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• 2016

Chemically amplified electrochemical detection, redox-active probe being amplified its electrochemical anodic current by a sacrificial electron donor presenting in solution, holds great potential for simple and quantitative bioanalytical analysis. Herein, we report the chemically amplified electrochemical analysis that drastically enhanced a detection of ferrocenemethanol (analyte) by ferrocyanide (chemical amplifier) on 4-nitrophenyl grafted glassy carbon electrodes at $60^{\circ}C$. The glassy carbon electrode grafted with a 4-nitrophenyl group using an electrochemical reduction suppressed the oxidation of ferrocyanide and thus enabled detection of ferrocenemethanol with excellent selectivity. The ferrocenemethanol was detected down to an nM range using a linear sweep voltammetry under kinetically optimized conditions. The detection limit was improved by decreasing the concentration of the ferrocyanide and increasing temperature.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.225-229
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• 2012

This paper proposes a reduced-scale simulator that can replace numerical analytic methods for the estimation of potential distribution caused by ground faults in various grounding systems. The simulator consists of a hemispherical electrolytic tank, a three-dimensional potential probe, a grounding electrode, and a data acquisition module. The potential distribution is measured using a potentiometer with a position-tracing function when a test current flows to the grounding electrode. Using the simulator, we could clearly analyze the potential distribution for a reduced- scale model by one-eightieth of the buried depth and length of the grounding rod and grounding grid. Once both the shape of the grounding electrode and the fault current are known, the actual potential distribution can be estimated.

• Journal of Semiconductor Engineering
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• v.1 no.3
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• pp.88-98
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• 2020

As biosensors are widely used in the medical field, flexible devices compatible with live animals have aroused great interest. Especially, significant research has been carried out to develop implantable or skin-attachable devices for real-time bio-signal sensing. From the device point of view, various biosensor types such as field-effect transistors (FETs) and multi-electrode arrays (MEAs) have been reported as diverse sensing strategies. In particular, the flexible FETs and MEAs allow semiconductor engineering to expand its application, which had been impossible with stiff devices and materials. This review summarizes the state-of-the-art research on flexible FET and MEA biosensors focusing on their materials, structures, sensing targets, and methods.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.831-841
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• 2010

The conventional vertical probe has the thin and long signal path that makes transfer characteristic of probe worse because of the S-shaped structure. So we propose the new vertical probe structure that has branch springs in the S-shaped probe. It makes closed loop when the probe mechanically connects to the electrode on a wafer. We fabricated the proposed vertical probe and measured the transfer characteristic and mechanical properties. Compared to the conventional S-shaped vertical probe, the proposed probe has the overdrive that is 1.2 times larger and the contact force that is 2.5 times larger. And we got the improved transfer characteristic by 1.4 dB in $0{\sim}10$ GHz. Also we developed the simulation model of the probe card by using full-wave simulator and the simulation result is correlated with measurement one. As a result of this simulation model, the cantilever probe and PCB have the worst transfer characteristic in the probe card.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.118-118
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• 2003

In a rolling wire probe, a key component of an inspection apparatus for PDP electrode patterns, the electric performance of it is known to be strongly dependent on the surface condition of a collet pin, a needle pin, and a wire. However, the collet and needle pins rotate very rapidly in contact with each other, which results in the degradation of the surface by the heat and friction and finally the formation of black wear marks on the surface after a several hundred hours test. Once the black wear marks appear on the surface, the electric resistance of the probe increases sharply and so the integrity of the probe is severely damaged. In this experiment, TiN coating, which has excellent electric conductances and good wear-resistance, has been applied on the surface of collect and needle pins for preventing the surface damages. In order to achieve the homogeneous coating with a good adhesion property, special coating substrate stages and jigs were designed and applied during coating. TiN has been deposited using 99.999% Titanium target by a DC reactive sputtering method. According to the components and jigs, processing parameters, such as DC power, RF bias and the flow rate ratio of Ar and N$_2$ used as reactive gases, has been controlled to obtain good TiN films. Detailed problems and solutions for applying the new substrate stages and jigs will be discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.319-324
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• 2011

This paper dealt with a partial discharge (PD) detection method for insulation diagnosis in cast-resin transformers. To detect PD pulse, a planar-capacitive probe was designed and fabricated. The probe has no insulation problem and can be installed on cast-resin transformers even in operation since it does not connect with high voltage conductor. The PD measurement system consists of the capacitive probe, a coupling network of 100 [kHz] low-cutoff frequency, and an amplifier with a gain of 40 [dB] and a frequency bandwidth of 500 [Hz]~45 [MHz]. A plane-needle and a plane-plane electrode system were fabricated to simulate insulation defects in a cast-resin transformer. Sensitivity of the PD measurement system, which is evaluated by a standard calibrator was 0.35 [mV/pC] for positive and 0.45 [mV/pC] for negative, respectively. The PD detection by the capacitive probe was less sensitive than that by a coupling capacitor according to IEC 60270, but we could analyze the magnitude and the phase distribution of PD pulse.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.265-269
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• 2014

Carbon nanofiber electrode has been fabricated for energy storage systems by the electrospinning of SU-8 precursor and subsequent pyrolysis. Various parameters including the applied voltage, the distance between syringe tip and target collector and the flow rate of the polymer affect the diameter of SU-8 electrospun nanofibers. Shrinkage during pyrolysis decreases the fiber diameter. As the pyrolysis temperature increases, the resistivity decreases dramatically. Low resistivity is one of the important characteristics of the electrodes of an energy storage device. Given the advantages of carbon nanofibers having high external surface area, electrical conductivity, and lithium intercalation ability, SU-8 derived carbon nanofibers were applied to the anode of a full lithium ion cell. In this paper, we studied the physical properties of carbon fiber electrode by scanning transmission microscopy, thermal gravimetric analysis, and four-point probe. The electrochemical characteristics of the electrode were investigated by cyclic voltammogram and electrochemical impedance spectroscopy plots.