• Korean Journal of Radiology
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• v.24 no.2
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• pp.86-94
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• 2023

Objective: To compare Octopus multipurpose (MP) electrodes, which are capable of saline instillation and direct tissue temperature measurement, and conventional electrodes for radiofrequency ablation (RFA) in porcine livers in vivo. Materials and Methods: Sixteen pigs were used in this study. In the first experiment, RFA was performed in the liver for 6 minutes using Octopus MP electrodes (n = 15 ablation zones) and conventional electrodes (n = 12 ablation zones) to investigate the effect of saline instillation. The ablation energy, electrical impedance, and ablation volume of the two electrodes were compared. In the second experiment, RFA was performed near the gallbladder (GB) and colon using Octopus MP electrodes (n = 12 ablation zones for each) with direct tissue temperature monitoring and conventional electrodes (n = 11 ablation zones for each). RFA was discontinued when the temperature increased to > 60℃ in the Octopus MP electrode group, whereas RFA was performed for a total of 6 minutes in the conventional electrode group. Thermal injury was assessed and compared between the two groups by pathological examination. Results: In the first experiment, the ablation volume and total energy delivered in the Octopus MP electrode group were significantly larger than those in the conventional electrode group (15.7 ± 4.26 cm³ vs. 12.5 ± 2.14 cm³, p = 0.027; 5.48 ± 0.49 Kcal vs. 5.04 ± 0.49 Kcal, p = 0.029). In the second experiment, thermal injury to the GB and colon was less frequently noted in the Octopus MP electrode group than that in the conventional electrode group (16.7% [2/12] vs. 90.9% [10/11] for GB and 8.3% [1/12] vs. 90.9% [10/11] for colon, p < 0.001 for all). The total energy delivered around the GB (2.65 ± 1.07 Kcal vs. 5.04 ± 0.66 Kcal) and colon (2.58 ± 0.57 Kcal vs. 5.17 ± 0.90 Kcal) were significantly lower in the Octopus MP electrode group than that in the conventional electrode group (p < 0.001 for all). Conclusion: RFA using the Octopus MP electrodes induced a larger ablation volume and resulted in less thermal injury to the adjacent organs compared with conventional electrodes.

• International Journal of Korean Welding Society
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• v.4 no.1
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• pp.15-22
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• 2004

Metal transfer behavior of three shielded metal arc welding electrodes, AWS El1018, E6013 and E6010, were investigated through the characterization of size distribution of droplets and measurement of arc voltage signals. Of the three electrodes, Ell018 electrode showed the largest droplet size with the smallest amount of spatter, while E6010 electrode showed the smallest droplet size with the largest amount of spatter. Even though Ell0l8 electrode showed a good agreement between the frequencies of voltage drop in FFT processed voltage signals and the transfer rate of droplets, E6013 and E6010 electrodes showed weaker correlation because of their dominant explosive transfer behavior. The type of cathode used and electrode baking time also influenced the metal transfer behavior. Compared to bead-on-plate welding using steel plate as a cathode, welding on a water-cooled copper pipe showed less short-circuiting and higher melting rate in all electrodes because of higher arc potential and/or anode drop. When baked for a long time, E6010 electrode showed much more stable arc with less short-circuiting and explosion due to the loss of gas formation ingredients.

• Journal of Sensor Science and Technology
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• v.19 no.1
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• pp.1-7
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• 2010

Electrostatic capacitance measurement method in a fine hose was proposed, in which two ring-type electrodes were disposed on the hose in the direction of fluid flow instead of the conventional face-to-face electrodes. With the proposed electrode structure, we realized a Ringer's solution exhaustion detector for an IV(invasive vein) injection set. On a 4 mm-diameter hose of IV set, we disposed two ring-type electrodes of 10 mm width at a distance of 5 mm each other and obtained 0.72 pF and 2.51 pF for air and 10 % dextrose Ringer's solution in the hose, respectively. The capacitance between the two electrodes varied with the hose-wraparound coverage of electrode as well as the width of electrode and the distance between the electrodes. For hose-wraparound electrode coverage of 75 %, the capacitance varied from 0.62 pF to 1.98 pF with the Ringer's solution level between the two electrodes. A charge amplifier converted the capacitance. variation into electric signal and a comparator was used to detect whether Ringer's solution was exhausted or not. The result was delivered to a host using a RF transmitter with 320 MHz carrier frequency.

• Journal of the Korean Ceramic Society
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• v.20 no.4
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• pp.356-360
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• 1983

The photocurrent vs. potential characteristics of the $TiO_2$ ceramic electrodes have been investigated as functions of numerous variables including sample purity hydrogen reduction condition and pH of the electrolyte. The difference inphotoresponse between 99.99% and 98.5% $TiO_2$ electrodes was due to electron trapping effect. As the hydrogen reducing temperature of $TiO_2$ electrodes were increased the photocurrent was also increased to certain condition and then decreased. These results can be explained by the behavior of oxygen vacancies.

• Journal of Electrochemical Science and Technology
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• v.4 no.4
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• pp.146-152
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• 2013

We demonstrate that carbon electrodes screen-printed directly on cellulose paper can be employed to perform bipolar electrochemistry. In addition, an array of 18 screen-printed bipolar electrodes (BPEs) can be simultaneously controlled using a single pair of driving electrodes. The electrochemical state of the BPEs is read-out using electrogenerated chemiluminescence. These results are important because they demonstrate the feasibility of coupling bipolar electrochemistry to microfluidic paperbased analytical devices (${\mu}PADs$) to perform highly multiplexed, low-cost measurements.

• Analytical Science and Technology
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• v.8 no.4
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• pp.683-689
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• 1995

Electrochemical reduction of carbon dioxide under high pressure on Fe electrodes and a gas diffusion electrode containing Pt catalyst (Pt-GDE) had been investigated. Formic acid was formed on Fe electrode with a faradaic efficiency of 60% at a current density of $120mA\;cm^{-2}$ under 30 atm of $CO_2$. Hydrocarbons such as $CH_4$, $C_2H_6$, $C_3H_6$, $1-C_4H_8$, and $n-C_5H_{12}$ are also formed. The distribution of hydrocarbons followed well the Schultz-Flory distribution. $CH_4$ was formed efficiently as the main reduction product on Pt-GDE.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.331-335
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• 1999

The transition metal oxides have been of interest as bifunctional electrocatalysts for bifunctional air electrodes. The amorphous citrate precursor (ACP) process has been optimized to prepare perovskite (La0.6Ca0.4CoO3) and pyrochlore (Pb2Ru2O6) powders with high surface area, and consequent improvement of The electrocatalytic performance in an air electrode with thermal treatment. PTFE -bonded gas diffusion electrodes loaded with perovskitc and pyrochlore catalysts showed good bifunctional performances. The electrodes were fairly stable up to 100 hour in the galvanostatic mode at ${\pm}25mA/cm^2$, from which these electrodes offer promise as practical bifunctional air electrodes.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.168.1-168.1
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• 2014

We developed poly (3,4-ethylene dioxylene thiophene):poly (styrene sulfonic acid) (PEDOT:PSS)-free organic solar cells (OSCs) using buffer and anode combined Ta doped $In_2O_3$ (ITaO) electrodes. To optimize the ITaO electrodes, we investigated the effect of $Ta_2O_5$ doping power on the electrical, optical, and structural properties of the co-sputtered ITaO films. The optimized ITaO film doped with 20 W $Ta_2O_5$ radio frequency power showed sheet resistance of 17.11 Ohm/square, a transmittance of 93.45%, and a work function of 4.9 eV, all of which are comparable to the value of conventional ITO electrodes. The conventional bulk heterojunction OSC with ITaO anode showed a power conversion efficiency (PCE) of 3.348% similar to the OSCs (3.541%) with an ITO anode. In addition, OSCs fabricated on an ITaO electrode successfully operated without an acidic PEDOT:PSS buffer layer and showed a PCE of 2.634%, which was much higher than the comparable no buffer OSC with an ITO anode. Therefore, co-sputtered ITaO electrodes simultaneously acting as a buffer and an anode layer can be considered promising transparent electrodes for cost-efficient and reliable OSCs because they can eliminate the use of an acidic PEDOT:PSS buffer layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.429-429
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• 2013

We present a systematic study of the electrical, optical and electromechanical properties of flexible graphene/metal grid hybrid transparent conductive electrodes using 4-point prove method, ultraviolet/visible spectrometer and inner/outer bending test system. The hybrid electrodes were synthesized by depositing a silver grid on a graphene surface. The sheet resistance of hybrid electrodes was as low as 30 Ω/square, while the transmittance was 90%. The electromechanical properties as a function of the change of bending radius were evaluated by measuring the change in resistance. The result will be presented in detail. We believe that these results will provide useful information for the flexible optoelectronic devices based on graphene transparent electrodes.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.36-41
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• 2019

Hybrid-type transparent electrodes were fabricated by depositing carbon nanotubes (CNTs) via spray coating on polyethylene terephthalate (PET) substrates and then coating the CNTs with [poly(3,4-ethylenedioxythiophene)] (PEDOT) films via electro-polymerization. For all of the fabricated electrodes, their surface morphologies, electric sheet resistances, visible transmittances, and color properties (e.g., yellowness) were characterized as functions of the applied voltages and process times used in electro-polymerization. The sheet resistance of the CNTs was significantly reduced by the coating of PEDOT, while their visible transmittances slightly decreased. The yellowness values of the PEDOT-coated CNTs were observed to have substantially decreased via electro-polymerization. The experimental results confirmed that the fabricated hybrid electrodes had desirable properties for the application of transparent electrode in terms of the electrical resistance, optical transmittance, and chromaticity.