• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2082-2088
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• 1995

In this paper, we designed and fabricated the magnetic bearings and built-in type cylindrical capacitive transducers for improving the vibration characteristics of rotating shaft. The eddy current and magnetic field from the electromagnet of the bearing don't affect the measuring signal of the capacitive type transducers so that it is possible to locate the capacitive sensor plates around the magnetic bearing poles and can improve the spillover problem which is induced by the noncollocation of the sensors and actuators. According to the sensitivity calibration schemes using a X-Y table, the cylindrical capacitive transducers have a good linearities in the .+-.70.mu.m range from the geometric center of the sensor plates. The measured results also show high displacement sensitivities of the sensors. According to the performance test of the magnetic bearing which is controlled by the analog PD controllers, we found that the built-in capacitive transducer system successfully measures the journal displacement in the magnetic field and therefore the magnetic bearing system supports the rotating shaft up to 12,000 rpm.

• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.1-7
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• 2015

In this paper, a new capacitive pressure sensor has been proposed for a displacement measurement. The new sensor is mainly composed of a gap of $5{\mu}m$ and a notch of $1{\mu}m$. And the sensor has the performance as the high sensitivity and capacitance compared with a commercial capacitive sensor. Therefore, the advantages of the new capacitive pressure sensor are good sensitivity in normal range, mechanically robust and large overload protection. The analytical model is induced for confirming the performance of the proposed sensor. In addition, FEM (finite elements method) simulation has been performed to verify the analytical model. Firstly, the displacement characteristics of diaphragm membrane were simulated by the analytical model and FEM in the case of different structure and materials. At last, through this analysis, these simulation results can be predicted the change of the performance when the device parameters are varied. And it is used as a design tool to achieve at a set of performance we desired.

• Fashion & Textile Research Journal
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• v.14 no.6
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• pp.1018-1023
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• 2012

Smartphone is integrated into the daily lives of all types of people not even young generation. A touch screen display is a primary input device of a smart phone, a tablet computer, etc. While there are many tough technologies in existence, resistive and capacitive are dominant and currently lead the touch screen panel industry. And a capacitive touch screen panel widely used in smart phones is coated with a material that stores electrical charges. In this study, we tried to manufacture gloves produced with electro-conducting leather as a tool to operate a touch panel screen. Therefore, electrically conductive materials, Polyaniline(PANI), Poly(3,4-ethylenedioxythiophene) (PEDOT), and Carbon nanotubes (CNT) were applied to the surface of leather to be used as a touching operator for capacitive touch screen panel. The leather samples were treated by simple painting method; firstly, they were painted with aqueous solution containing each of the electrically conductive materials and then dried. This cycle was repeated three times. Consequently, the treated leather samples showed electrical conductivity and reasonable working performance to the capacitive touch screen. And, PANI showed the best performance and highest electrical conductivity, and then PEDOT and, CNT in decreasing order. This is because the solubilities of PANI and PEDOT show higher than dispersibility of CNT. Thus, the concentration of conducting polymers was greater than that of CNT in the treating solutions.

• Membrane Journal
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• v.30 no.5
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• pp.350-358
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• 2020

A membrane capacitive deionization (MCDI) cell is constructed by applying thin layer of a cation exchange membrane (Nafion) on cathode and an anion exchange membrane (aminated polyphenylene oxide, APPO) on anode. Compared to CDI cell without CEM and AEM coating, MCDI exhibits enhanced salt removal efficiency. When Nafion and APPO are used as CEM and AEM, optimized salt removal performance as high as 82.1% is observed when 1.2 V is applied for 3 min during absorption process and -1.0 V is applied for 1 min during desorption.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.103-107
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• 2021

In this paper, a capacitive water level sensor for boilers was developed. In order to accurately monitor the water level in a high-temperature boiler that generates a lot of precipitates, the occurrence of precipitates on the surface of the water level sensor should be small, and a sensor capable of measuring even if the sensor surface is somewhat contaminated is required. The capacitive water level sensor has a structure in which one of the two electrodes is insulated with Teflon coating, and the stainless steel package of the water level sensor is brought into contact with the water tank so that the entire water tank becomes another electrode of the water level sensor. A C-V converter that converts the capacitance change of the capacitive water level sensor into a voltage change was developed and integrated with the water level sensor to minimize noise. The performance of the developed capacitive water level sensor was evaluated through measurement.

• Journal of the Korean Society of Visualization
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• v.20 no.2
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• pp.13-20
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• 2022

An effective capacitive deionization process termed membrane capacitive deionization (MCDI) is newly designed and experimentally tested for seawater desalination. By preventing co-ions to be expelled, MCDI can improve the ion removal performance, but there is a trade-off between blocking co-ion transfer and increasing contact resistance. The conventional MCDI uses 2D-shaped films which increase contact resistance and reduce desalination performance in the trade-off. In this paper, with the 3-D shape of Nafion coated activated carbon cloth, the mentioned problems are expected to be solved making the desalination performance better. We visualized ion concentration and fluid flows with half-MCDI cell that can measure only efficiency of cathode. We found the optimal number of coatings which have the better efficiency than CMX, commercial cation exchange membrane in fixed current conditions of 100uA.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.121-126
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• 2005

This paper describes the attributes, performance and development status of a high performance capacitive torque sensor intended for use in a electric power steering (EPS) system. The EPS system is composed of torque sensor, ECU, motor, gears and etc. Among the elements, torque sensor in the steering column is one of the core technologies. The new capacitive torque sensor in this paper is developed differently from working principle and mechanical structure compare to extant torque sensors in market and patent. Based on the result of numerical analysis, a experimental equipment is made which is composed of a test jig and a capacitive sensor and validity of numerical analysis and feasibility of the torque sensor are verified.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1103-1104
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.60-67
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• 2007

A signal conditioning circuit for capacitive displacement sensors was developed using a high frequency modulation/demodulation method, and its performance was evaluated. Since capacitive displacement sensors can achieve high resolution and linearity, they have been widely used as precision sensors within the range of several hundred micrometers. However, they inherently have a limitation in low frequency range and some nonlinearity characteristics and so a specially designed signal conditioning circuit is needed to handle these properties. The developed signal processing circuit consists of three parts: linearization, modulation/demodulation, and nonlinearity compensation. Each part was constructed discretely using several IC chips and passive elements. An evaluation system for precision displacement sensors was developed using a laser interferometer, a precision stage, and a PID position controller. The signal processing circuit was tested using the evaluation system in the respect of resolution, repeatability, linearity, and so on. From the experimental results, we know that a highly linear voltage output can be obtained successfully, which is proportional to displacement and the nonlinearity of output is less than 0.02% of full range. However, in the future, further investigation is required to reduce noise level and phase delay due to a low-pass filter. The evaluation system also can be applied effectively to calibration and evaluation of precision sensors and stages.

• Carbon letters
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• v.23
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• pp.9-16
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• 2017

This paper introduces a nitrogen-doped ordered mesoporous carbon (NOMC) derived from glucosamine with hybrid capacitive behaviors, achieved by successfully combining electrical double-layer capacitance with pseudo-capacitance behaviors. The nitrogen doping content of the fabricated NOMC reached 7.4 at% while its specific surface area ($S_{BET}$) and total pore volume reached $778m^2g^{-1}$ and $1.17cm^3g^{-1}$, respectively. A dual mesoporous structure with small mesopores centered at 3.6 nm and large mesopores centered at 9.9 nm was observed. The specific capacitance of the reported materials reached up to $328Fg^{-1}$, which was 2.1 times higher than that of pristine CMK-3. The capacitance retention rate was found to be higher than 87.9% after 1000 charge/discharge cycles. The supplementary pseudocapacitance as well as the enhanced wettability and conductivity due to the incorporation of nitrogen heteroatoms within the carbon matrixes were found to be responsible for the excellent capacitive performance of the reported NOMC materials.