• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.134-144
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• 1995

The solenoid actuated hydrogen injector and the capacitive peak-hold type driving circuit were designed and made, and the hydrogen supply system for in-cylinder injection was constructed with these. The performance of the injector was investigated through measuring the pintle lift profiles and the injection quantities, and the performance of the hydrogen supply system was confirmed through the experiments at the single cylinder engine. The injection quantity increased linearly as the duration of driving signal increased. At the single cylinder engine, the hydrogen injector was operated stably. The hydrogen flow rate of the injector with the peak-hold type driving circuit could be controlled precisely at high engine speed or low load condition only with the variation of signal duration.

• Journal of computational fluids engineering
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• v.15 no.1
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• pp.31-36
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• 2010

In the present study, computations for flow fields inside the CDI unit cells with electrodes and spacers have been made to evaluate their performance. Three types of unit cells that include a planar type, a serpentine channel type, and a spiral wound type were considered and their flow characteristics were compared. From the computational results, it is found that the serpentine channel type has a large flow resistance and can not guarantee the outflow flux for industrial applications. On the other hand, the planar type can sustain a large enough outflow flux but it's efficiency is low for the electrode-use because of the non-uniform velocity distribution inside the cell and dead zones in every corner. Finally, The spiral wound type has not only a large outflow flux as much as the planar type has, but also a high efficiency for the electrode-use because of uniform velocity distribution. From this comparison, we can expect that the spiral wound type of CDI unit cell would have a high performance deionization capability.

• Science of Emotion and Sensibility
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• v.15 no.4
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• pp.415-424
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• 2012

According to introduction of Well-Being lifestyle and ageing society, vital sign monitoring system which can be continued measurement of vital sign has been increased their important in field of the healthcare. Under this trend, Respiration monitoring system has been studied and developed in a various way to apply continued monitoring and non-conscious monitoring system. But, Study of the respiration monitoring system based on consumer needs and usability test is insufficient. In this study, Textile capacitive pressure sensor(TCPS) of belt type was developed and tested it's utility and subjective sensibility. TCPS measures respiration signals and can be derived in real time monitoring. As a result, monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rate (correlation (r＝0.9553, p<0.0001). In the result of usability and wearability test, all of categorizes(perceived change, wearability, movement, facility of management, usefulness) were received favorable evaluation on usability test( mean value : 3.8), and suitable location of TCPS in the clothing is deriven on the abdomen part. According to synthetical results, Basic smart clothing design based on respiration monitoring system is proposed.

• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.415-420
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• 2007

In this paper, we have designed and fabricated a new type of bandpass-filter that used rectangular ring and interdigital capacitive feeding-structure. The filter is applied the modified rectangular ring and interdigital capacitive feeding-structure in patch, which reduce rho size of filter and IEEE 802. 11 correspond to wireless LAN domain(2.45GHz and 5.2GHz) for operating. As a result, the design and fabrication process of the filter become simple and the size of it is reduced more than 60% compared with RF filter are available conventional PEMBF(Parallel Edge-coupled Microstrip Bandpass Filter) of accounted circuit by minimum stage, measurement result of fabricated filter, center frequence is down 2.408GHz and 5.075GHz. input return loss is -39.169dB at 2.408GHz, -40.922dB at 5.075GHz. insertion loss is -0.437dB at 2.408GHz, -1.669dB at 5.075GHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.225-229
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• 2011

In this study, capacitive type pressure sensors based on low temperature co-fired ceramics (LTCC) technology for environmental monitoring were demonstrated. The LTCC is one of promising technology than is based one since it has many advantages (e.g., low cost production, high manufacturing yields and easy realizing 3D structure etc.) for sensor application. Especially, it has good mechanical and chemical properties for robust environmental application. The 3D LTCC diaphragm with thickness of 400 ${\mu}m$ were fabricated by laminating 4 green sheets using commercial powder (NEG, MLS 22C). To evaluate the sensing properties of the different cavity areas, two types of diaphragm which had different cavity areas with 25, 49 $mm^2$ respectively, were fabricated. To realize capacitive type pressure sensor, the Au top electrode was fabricated using thermal evaporator and the bottome electrode was compressed using aluminium foil. The sensing properties of the fabricated sensors showed linear characteristic under different pressure (0~30 psi) using pressure measurement system.

• Journal of Power Electronics
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• v.4 no.3
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• pp.138-151
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• 2004

In this paper, a constant frequency phase shifting PWM-controlled voltage source full bridge-type series load resonant high-frequency inverter using the $4^{th}$ generation IGBT power modules is presented for innovative consumer electromagnetic induction heating applications, such as a hot water producer, steamer and super heated steamer. The bridge arm side link passive capacitive snubbers in parallel with each power semiconductor device and AC load side linked active edge inductive snubber-assisted series load resonant tank soft switching inverter with a constant frequency phase shifted PWM control scheme is evaluated and discussed on the basis of the simulation and experimental results. It is proved from a practical point of view that the series load resonant and edge resonant hybrid high-frequency inverter topology, what is called, DE class type, including the variable-power variable-frequency regulation function can expand zero voltage soft switching commutation area even under low output power setting ranges, which is more suitable and acceptable for newly developed induction heated dual pack fluid heaters. Furthermore, even the lower output power regulation mode of this high-frequency load resonant tank inverter circuit is verified so that this inverter can achieve ZVS with the aid of the single auxiliary inductor snubber.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.9-13
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• 2002

This paper describes the first-year accomplishments in the R'||'&'||'D project entitled, "Electrodeless Fluorescent Lamp Technology Using High-Frequency Discharges (Linear and Circular Type)," supported by a contract from the Korea Energy Management Corporation (KEMCO). One of the most important accomplishments in the prihect is that the luminance of electrodeless fluorescent lamps is increased more than 25% when the hybrid technique of capacitive and inductive couplings is utilized for both linear and circular types of high-frequency discharge fluorescent lamps compared to the case where pure capacitive couplings are used. We present the results of the experiments and the status of the development efforts in the project.t.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.135-141
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• 2005

Measurement of five DOF motion errors in a ultra precision feed table was attempted in this study. Yaw and pitch error were measured by using a laser interferometer and roll error was measured by using the reversal method. Linear motion errors in the vertical and horizontal directions were measured by using the sequential two point method. In this case, influence of angular motion errors was compensated by using the previously measured ones by the laser interferometer and the reversal method. The capacitive type sensors and an optical straight edge were used in the reversal method and the sequential two point method. Influence of thermal deformation on sensor jig was investgated and minimized by the periodic measurement according to the variation of room temperature. Deviation of gain between sensors was also compensated using the step response data. 5 DOF motion errors of a hydrostatic table driven by the linear motor werer tested using the measurement method. In the horizontal direction, measuring accuracies for the linear and angular motion were within ${\pm}0.02\;{\mu}m$ and ${\pm}0.04$ arcsec, respectively. In the vertical direction, they were within ${\pm}0.02{\mu}m$ and ${\pm}0.05$ arcsec. From these results, it was found that the introduced measurement method was very effective to measure 5 DOF motion errors of the ultra precision feed tables.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1657-1658
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• 2006

An external electrode fluorescent lamps (EEFLs) have the advantage of a long lifetime in the early stages of the study on plasma discharge, interest in the lamp continues. Studies on the operation of external electrode fluorescent lamps have focused mainly on its use of a type of high frequency (MHz). By performing high brightness using a square wave operation method with the low frequency below 100kHz, which is applied to a narrowed tube type lamp that has several mm of lamp diameter. To solve these problems of CCFL, EEFL (External Electrode Fluorescent Lamp) is introduced. Because electrode of EEFL is on the outer surface of discharge tube, the electrode is perfectly prevented from the sputtering by accelerated ions. And it is possible to drive the many CCFLs at the same time, because EEFL shows the positively resistant characteristic. But EEFL has the large non-radiative power loss in sheath. In this study the novel electrode structure was introduced in order to reduce non-radiative power loss in sheath of EEFL. The novel electrode structure comes from the idea to combine conceptually capacitive discharge with inductive discharge. Thus, this study verifies the change in the optical characteristics according to the change in electrode structure through a Maxwell's electromagnetic field simulation and examines the relationship between the change in the EEFL electrode structure and brightness by measuring the optical characteristics.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.159-164
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• 2021

As the attachable-type wearable devices have received considerable interests, the need for the development of high-performance electrode materials of fabric or textiles type is emerging. In this study, we demonstrated the electrochemical property of CNT fibers electrode as a flexible electrode material and its non-enzymatic glucose sensing performance. Surface morphology of CNT fibers was observed by SEM. And the electrochemical characteristics were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The CNT fibers based sensor exhibited improved sensing performances such as high sensitivity, a wide linear range, and low detection limit due to improved electrochemical properties such as low capacitive current, good electrochemical activity by efficient direct electron transfer between the redox species and the electrode interface. Therefore, this study is expected to be used as a basic research for the development of high performance flexible electrode materials based on CNT fibers.