• Journal of Biomedical Engineering Research
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• v.26 no.1
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• pp.49-54
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• 2005

This paper presents a design of 1-channel active dry electrode module for EEG from one's forehead. The IA(instrumentation amplifier) circuit inside the module is based on the configuration sown on the paper MettingVanRijn et al. We analyze the IA circuit to find out the related equation, and then compare its simulated characteristic with the result obtained from the real active dry electrode circuit. With the active dry electrode and the wet(Ag/AgCI) electrode connected to the separated analog processing module on one's forehead at the same time, their real time and FFT outputs of EEG are examined for comparison. The active dry electrode module has advantages over the wet electrode and its analog processing module: 1) The size of the analog processing circuit of the active dry electrode module is smaller than that of existing EEG analog processing module; 2) the total cost required to make the proposed analog processing circuit is much lower than that of the existing circuit, since the designed circuit needs smaller parts; 3) the electrical characteristic is comparable to the general EEG analog processing module even if the designed module has simpler circuit configuration.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2733-2736
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• 2003

This paper proposes a dry-type active surface EMG electrode for the myoelectric prosthetic hand. The designed electrode is small size for embedding in the socket of prosthetic hand, and it has three leads including the reference of signal. To acquire EMG signal rejected the power noise, a precision differential amplifier and various filters such as the band pass filter band rejection filter, low pass and high pass filter are embedded on the electrode. The final output of the electrode is integrated absolute EMG (IEMG) obtained by full rectifier and moving average circuits. From experimental results using the implemented dry-type active surface EMG electrode, the proposed electrode is feasible for the myoelectric prosthetic hand.

• Annals of Clinical Neurophysiology
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• v.13 no.2
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• pp.80-86
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• 2011

Background: A dry-type electrode is an alternative to the conventional wet-type electrode, because it can be applied without any skin preparation, such as a conductive electrolyte. However, because a dry-type electrode without electrolyte has high electrode-to-skin impedance, an impedance-converting amplifier is typically used to minimize the distortion of the bioelectric signal. In this study, we developed an active dry electroencephalography (EEG) electrode using an impedance converter, and compared its performance with a conventional Ag/AgCl EEG electrode. Methods: We developed an active dry electrode with an impedance converter using a chopper-stabilized operational amplifier. Two electrodes, a conventional Ag/AgCl electrode and our active electrode, were used to acquire EEG signals simultaneously, and the performance was tested in terms of (1) the electrode impedance, (2) raw data quality, and (3) the robustness of any artifacts. Results: The contact impedance of the developed electrode was lower than that of the Ag/AgCl electrode ($0.3{\pm}0.1$ vs. $2.7{\pm}0.7\;k{\Omega}$, respectively). The EEG signal and power spectrum were similar for both electrodes. Additionally, our electrode had a lower 60-Hz component than the Ag/AgCl electrode (16.64 vs. 24.33 dB, respectively). The change in potential of the developed electrode with a physical stimulus was lower than for the Ag/AgCl electrode ($58.7{\pm}30.6$ vs. $81.0{\pm}19.1\;{\mu}V$, respectively), and the difference was close to statistical significance (P=0.07). Conclusions: Our electrode can be used to replace Ag/AgCl electrodes, when EEG recording is emergently required, such as in emergency rooms or in intensive care units.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.411-414
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• 2009

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using simple sandwich capacitor electrode method as carbonaceous material on each type of capacitor electrodes with 20 ${\times}$ 15 mm cell size. Carbon/active carbon cell was fabricated using sol-gel process with 120oC dry temperature in l hour and using sintering process with 500oC in 2 hour. The effect of sintering temperature on carbon properties was also investigated with X-ray diffraction technique to get the best sintering temperature. The detail of fabrication process will be explained. Elemental composition in electrode material can be measured using quantitative spectroscopic as and a cyclic voltammetric technique was used to study the combined effects of electrode material and effect of annealing temperature and also time on the capacitance of thermally treated in capacitor electrode. In this work, characterization impedance technique is used to measurement of capacitance and giving complementary results. Active carbon as carbonaceous material has a better capacitance in charge/discharge process with mean thickness $32{\mu}m$ and with particle size $1{\mu}m$ to $4.5{\mu}m$ in 20 ${\times}$ 15 mm sample size of capacitor electrode.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.57-63
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• 2010

Photo-capacitor electrodes are attracting great attention because of their high capacitance and potential applications in electronic devices. Carbon capacitor, active carbon capacitor and its combination will be fabricated using a sandwich method as carbonaceous material on each type of storable electrode with $20{\times}15$[mm] cell size. Carbon/active carbon cell was fabricated using sol-gel process with $120[^{\circ}C]$ dry temperature in 2hour and using sintering process with $500[^{\circ}C]$ in 2hour. The effect of sintering temperature on carbon properties was also investigated with an X-ray diffraction technique to get the best sintering temperature. The detail of the fabrication process will be explained. Active carbon as carbonaceous material has a better capacitance in storable electrode with mean thickness $32[{\mu}m]$ and with particle size $1[{\mu}m]$ to $4.5[{\mu}m]$ in $20{\times}15$[mm] sample size of storable electrode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.366-371
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• 2017

In this paper, we introduce an electrocardiogram (ECG) system designed to solve problems caused by wetgels and motion artifacts in measuring active movement. The system is called a dry-contact ECG and was designed by considering impedance matching between skin and electrode as well as the frictional electricity between electrode and clothes. In order to create the system, we measured impedance on the skin-electrode interface, and the result was applied to the electronic circuit scheme. Moreover, we added an electrode on the back of the measurement electrode to make a flow path to ground the electrical noise. The final ECG circuit and novel electrode were used to detect real human cardiac signals from a subject who was tested while standing still and walking. The signals obtained from the two activities were nicely shaped, without any motion artifact noise. We took electrode size into account in this study because the impedance depended on the area of the electrode. An electrode of 50 mm diameter showed the best curve for the ECG signal without any electrical noise.

• Journal of Hydrogen and New Energy
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• v.27 no.3
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• pp.264-269
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• 2016

A simple dry chemical approach was developed in order to load palladium (Pd) as a promoter on Pt/gas diffusion electrode (GDE) for polymer electrolyte membrane fuel cell (PEMFC). Palladium(II) bis (acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into Pt/GDE and then reduced to Pd nanoparticles simultaneously without any reducing agent and any solvent in a glass reactor of $N_2$ atmosphere at $180^{\circ}C$ for 3, 5 and 15 min. Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.269-272
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• 1997

The Lithium ion secondary battery has been developed for high energy density of portable electrical device and electronics. Among the many conductive polymer materials, the positive active film for Li polymer battery system was synthesized successfully from polyphenylene diamine(PPD) by chemical polymerization in our lab. And PPD-DMcT(2, 5-dimercapto-1, 3, 4-thi-adiazole) composite flim conductive material, at high temperature was also prerared with the addition of dimethylsulfoxide(DMSO). The surface morphology and thermal stability of prepared composite flim was carried out by using SEM and TGA, respectively. Electrochemical and electrical conductivity of composite flim were also discussed by cyclic voltammetry and four-probe method in dry box(<27pm). And the electrode reaction mechanism was detected and analyzed from the half cell unit battery system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1224-1231
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• 2003

This paper reports on the air-gap type thin film bulk acoustic wave resonator(FBAR) using ultra thin wafer with thickness of 50$\mu\textrm{m}$. It was fabricated to realize a small size devices and integrated objects using MEMS technology for flexible microsystems. To reduce a error of experiment, MATLAB simulation was executed using material characteristic coefficient. Fabricated thin FBAR consisted of piezoelectric film sandwiched between metal electrodes. Used piezoelectric film was the aluminum nitride(AlN) and electrode was the molybdenum(Mo). Thin wafer was fabricated by wet etching and dry etching, and then handling wafer was used to prevent damage of FBAR. The series resonance frequency and the parallel frequency measured were 2.447㎓ and 2.487㎓, respectively. Active area is 100${\times}$100$\mu\textrm{m}$$^2$.Q-factor was 996.68 and K$^2$$\_$eff/ was 3.91％.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.235-240
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• 2010

We investigated the carbon monoxide (CO) gas-sensing properties of nanostructured Al-doped zinc oxide thin films deposited on self-assembled Au nanodots (ZnO/Au thin films). The Al-doped ZnO thin film was deposited onto the structure by rf sputtering, resulting in a gas-sensing element comprising a ZnO-based active layer with an embedded Pt/Ti electrode covered by the self-assembled Au nanodots. Prior to the growth of the active ZnO layer, the Au nanodots were formed via annealing a thin Au layer with a thickness of 2 nm at a moderate temperature of $500^{\circ}C$. It was found that the ZnO/Au nanostructured thin film gas sensors showed a high maximum sensitivity to CO gas at $250^{\circ}C$ and a low CO detection limit of 5 ppm in dry air. Furthermore, the ZnO/Au thin film CO gas sensors exhibited fast response and recovery behaviors. The observed excellent CO gas-sensing properties of the nanostructured ZnO/Au thin films can be ascribed to the Au nanodots, acting as both a nucleation layer for the formation of the ZnO nanostructure and a catalyst in the CO surface reaction. These results suggest that the ZnO thin films deposited on self-assembled Au nanodots are promising for practical high-performance CO gas sensors.