• 전기학회논문지
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• 제67권12호
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• pp.1626-1632
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• 2018

In this paper, we describe the fabrication and characterization of a hydrogen peroxide ($H_2O_2$) sensor based on palladium and copper (PdCu) electroplated laser induced graphene (LIG) electrodes. $CO_2$ laser was used to form LIG electrodes on a PI film. This fabrication method allows simple control of the LIG electrode size and shape. The PdCu was electrochemically deposited on the LIG electrodes to improve the electrocatalytic reaction with $H_2O_2$. The electrochemical performance of this sensor was evaluated in terms of selectivity, sensitivity, and linearity. The physical characterization of this sensor was conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), which confirmed that PdCu was formed on the laser induced graphene electrode. In order to increase the sensor sensitivity, the Pd:Cu ratio of the electroplated PdCu was varied to five different values and the condition of highest amperometric current at an identical of $H_2O_2$ concentration was chosen among them. The resulting amperometric current was highest when the ratio of Pd:Cu was 7:3 and this Pd;Cu ratio was employed in the sensor fabrication. The fabricated PdCu/LIG electrode based $H_2O_2$ sensor exhibited a sensitivity of $139.4{\mu}A/mM{\cdot}cm^2$, a broad linear range between 0 mM and 16 mM of $H_2O_2$ concentrations at applied potential of -0.15 V, and high reproducibility (RSD = 2.6%). The selectivity of the fabricated sensors was also evaluated by applying ascorbic acid, glucose, and lactose separately onto the sensor in order to see if the sensor ourput is affected by one of them and the sensor output was not affected. In conclusion, the proposed PdCu/LIG electrode based $H_2O_2$ sensor seems to be suitable $H_2O_2$ sensor in various applications.

• 센서학회지
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• 제22권3호
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• pp.202-206
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• 2013

In this paper, a disposable glucose sensor was made of paper. Glucose sensor strip using carbon electrode is appropriate for the low price ones because it requires cheap materials and low cost production. Most of blood glucose sensors were developed with plastics, but it causes pollution problems. Therefore we developed disposable carbon electrode glucose sensor using paper. This sensor consists of upper and bottom plate. On the upper plate, three-dimensional channel are formed through pressing process. The fabricated paper glucose sensor shows relatively short sensing time of about 5seconds, excellent reproducibility ($R^2$=0.9558), and fabrication yield as well.

• 센서학회지
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• 제24권2호
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• pp.83-87
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• 2015

In this paper, we fabricated a low-cost glucose sensor with a simpler structure and fabrication process than the existing glucose sensor. The currently used glucose sensor has a three-layer structure with upper, middle, and bottom plates; here, we fabricated a single-layer glucose sensor using only a printing and dispensing process. We successfully fabricated the glucose sensor using a simple method involving the formation of an electrode and insulator layer through a 2- or 3-step printing process on plastic or paper film, followed by the dispensing of glucose oxidase solution on the electrode. Cyclic voltammetry (CV) and cyclic amperometry (CA) measurements were used to evaluate the characteristics of the fabricated single-layer glucose sensor. Also, its sensitivity was analyzed through glucose-controlled blood measurements. Hence, a low-cost single-layer glucose sensor was fabricated with evaluation of its characteristics demonstrating that it has useful application in medicine.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.2001-2006
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• 2017

This paper explains the effects of the weak signal of a rotating-type electric field mill sensor fabricated for measuring the intensity of the electric field generated by high-voltage direct current (HVDC) power transmission lines. The fabricated field mill consists of two isolated electrode vanes, a motor driver, and a ground part. The sensor plate is exposed to and shielded from the electric field by means of a rotary shutter consisting of a motor-driven mechanically complementary rotor/stator pair. When the uncharged sensor plate is exposed to an electric field, it becomes charged. The rotating electrode consists of several conductive vanes and is connected to the ground part, so that it is shielded. Determining the appropriate design variables such as the speed of the vane, its shape, and the distance between the two electrodes, is essential for ensuring optimal performance. By varying the speed, the weak signal characteristics which is used to signal processing and calibration experiment are quite different. Each weak signal pattern was analyzed along with the output voltage characteristics, in order to be able to determine the intensity of the electric field generated by HVDC power transmission lines with accuracy.

• 한국생산제조학회지
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• 제21권5호
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• pp.720-725
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• 2012

Sodium hypochlorite is used worldwide as a water disinfectant and in bleaching agent. Sodium hypochlorite applied to water initially undergoes hydrolysis to form free chlorine consisting of hypochlorous acid(HOCl) and hypochlorite ion($OCl^-$). For free chlorine determination, an electrochemical method is simple due to the electroactivity of free chlorine; it measures current and is free of most reagents. Amperometric free chlorine sensor has been developed with gold (Au)-based electrode. The 3-electrode free chlorine sensor whose working and counter electrodes were Pt exhibited excellent response to HClO at +400mV vs. Ag/AgCl/sat. KCl. In addition, the use of a pH error correction algorithm provided a reliable measurement of residual free chlorine in water sample without any pretreatment in the normal pH range(pH 6~8) of municipal water supply. The free chlorine sensor installed in on-line monitoring system could be used to continually monitor the level of residual free chlorine in real samples.

• 한국의류학회지
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• 제45권1호
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• pp.168-179
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• 2021

This study presents and develops a textile type touch sensor structural design that is easy to implement. First, the design of the touch sensor circuit finds the size of the switch with the easiest finger contact and selects a structure with a long circuit with the lowest resistance value. An experiment is performed on a change in an electrostatic capacitance value that accompanies the distance on the electrode and the magnitude of the electrode area of the structure; however, the structure having the distance on the electrode and the large electrode area shows the best resistance change. The laundry assessment was conducted three times at a time and ten times at a time with an average standard deviation less than one ohm, with little change in resistance. Consequently, there were no problems with durability and performance for laundry. Finally, in the bending evaluation, the difference in resistance can be seen between 1-2 ohms and was developed as a smart wearable in the future; in addition, there was no problem as a difference in resistance can be seen between 1 and 2 ohms.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.177-181
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• 2004

A PVC membrane electrode for silver ion based on a new cone shaped calix[4]arene (CASCA) as membrane carrier was prepared. The electrode exhibits a Nernstian response for $Ag^+$ over a wide concentration range ($1.0{\times}10^{-1}-8.0{\times}10^{-6}$M) with a slope of 58.2 {\pm}$ 0.5 mV per decade. The limit of detection of the sensor is $5.0{\times}10^{-6}$M. The sensor has a very fast response time (~5 s) in the concentration range of ${\leq}=1.0{\times}10^{-3}$ M, and a useful working pH range of 4.0-9.5. The proposed sensor displays excellent discriminating ability toward $Ag^+$ ion with respect to common alkali, alkaline earth, transition and heavy metal ions. It was used as an indicator electrode in potentiometric titration of $Ag^+$ with EDTA and in direct determination of silver ion in wastewater of silver electroplating.

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1394-1398
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• 2002

A novel copper(II) membrane electrode based on diphenylisocyanate bis(acetylacetone) ethylenediimine (DIBAE), as a new hexadentates Schiff's base was prepared. The electrode exhibited a Nernstian response for Cu$^{2+}$ ions over a wide concentration range (1.0 ${\times}$ 10$^{-1}$ to 1.0 ${\times}$ l0$^{-6}$ M) with a limit of detection of 6.0 ${\times}$ 10$^{-7}$ M (39 ppb). The sensor shows a fast response time (15s) and the membrane can be used for more than 4 months without observing any major deviation. The electrode revealed very good selectivity with respect to many cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor could be used in a pH range of 3.0-7.5. It was applied to the direct potentiometric determination of copper in black tea, and in wastewater of copper electroplating samples. The electrode was also used in potentiometric titration of the copper(II) ion with EDTA.

• 소음진동
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• 제7권6호
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• pp.967-974
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• 1997

Distributed piezoeletric sensor and actuator have been designed for efficient vibration control of a cantilevered beam. Both PZT and PVDF have been used in this study, the former as an actuator and the latter as a sensor for the integrated structure. We have optimized the position and the size of the PZT actuator and the electrode shape of the PVDF sensor. Finite element method is used to model the structure and the optimized actuators, we have designed the active electrode width of the PVDF sensor along the span of the beam. Actuator design is based on the criterion of minimizing the system energy in the control modes under a given initial condition. Model control forces for the residual (uncontrolled) modes have been minimized during the sensor design to minimize the observation spill-over. Genetic algorithm and sequential quadratic programming technique have been utilized as an optimization scheme. Discrete LQG control law has been applied to the integrated structure for real time vibration control. Performance of the sensor, the actuator, and the integrated smart structure has been demonstrated by experiments.

• 센서학회지
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• 제6권6호
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• pp.437-444
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• 1997

A potentiometric L-lysine-selective sensor is described for the direct determination of lysine. The sensor system is based on a carbon dioxide gas sensing electrode and an L-lysine decarboxylase immobilized to CNBr-activated sepharose 4B. A highly selective L-lysine sensor has been prepared with immobilizing enzyme slurry put into reaction buffer solution. The optimum conditions for the measurement were evaluated by various experiments. This sensor exhibits a linear response to L-lysine concentrations from $10^{-4}M$ to $10^{-1}M$. Response time of this lysine sensor is shorter than 30secs and the immobilized enzyme slurry is stable over one year.