• 한국항공우주학회지
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• 제48권12호
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• pp.1013-1020
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• 2020

스파크 유도 플라즈마 분광법 (SIBS)은 전기 스파크를 사용하여 강력한 플라즈마를 유도한 후 원자 방출 스펙트럼 신호를 수집하는 방법이다. 이 연구는 우주 탐사에 활용되는 기존의 레이저 유도 분해 분광법 (LIBS) 대신 SIBS를 사용할 수 있는지의 잠재력을 보기 위해 진행되었다. 과거에는 SIBS를 사용하여 부피가 큰 고체 샘플을 대상으로 실험하는 것이 성공적이지 않았기 때문에, 본 연구에서는 전극 위치 및 전극 재료의 SIBS의 최적화 연구가 수행되었다. LIBS를 사용할 때에 비해 SIBS의 검출 한계 (LOD)가 78에서 20ppm으로 최대 4배 향상되어 있음을 볼 수 있었다. 생성된 플라즈마의 더 높은 에너지로 인해, SIBS에 의한 신호 세기는 동일한 분광계 설정에서 LIBS보다 3배 정도 높았다.

• 한국정밀공학회지
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• 제16권10호
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• pp.141-151
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• 1999

The resistance Spot Welding is widely used in the field of assembling the plates. However we don't still have any satisfactory solution, which is non-destructive quality evaluation in real-time or on-line, against it. Moreover, even though the rate of welding under the condition of expulsion has been high until now, quality control of welding against expulsion hasn't still been established. In this paper, it was proposed on the quality assurance technique of resistance spot welding pieces using Neuro-Fuzzy algorithm. Four parameters from electrode separation signal in the case of non-expulsion, and dynamic resistance patterns in the case of expulsion are selected as fuzzy input parameters. The parameters consist of Fuzzy Inference System are determined through Neuro-Learning algorithm. And then, fuzzy Inference System is constructed. It was confirmed that the fuzzy inference values of strength have within ${\pm}$4% error specimen in comparison with real strength for the total strength range, and the specimen percent having within ${\pm}$1% error was 88.8%. According to KS(Korean Industrial Standard), tensile-shear strength limit for electric coated of zinc is 400kgf/mm2. Judging to the quality of welding is good or bad, according to this criterion and the results of inference, the probability of misjudgement that good quality is valuated into poor one was 0.43%, on contrary it was 2.59%. Finally, the proposed Neuro-Fuzzy Inference System can infer the tensile-shear strength of resistance spot welding pieces with high performance for all cases-non-expulsion and expulsion. And On-Line Welding Quality Inspection System will be realized sooner or later.

• Journal of the korean society of oceanography
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• 제36권1호
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• pp.1-8
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• 2001

An in-situ four-electrode contact resistivity probe system was designed, and field-tested in submarine sediments. Seismic survey was also performed to support and compare the results of electric survey. The probe was designed to be driven to selected depths below the seafloor using a Vibracore system. The four insulated electrodes were, spaced equidistant across the wedge, were extended beyond the probe tip to minimize effects of sediment disturbance by the wedge insertion. In-situ measurements of resistivity were recorded on board by precision electronic equipment consisting of signal generators and processors, and by temperature-monitoring systems. Overall limits of Uncertainty at respective depths below the seafloor are up to ${\pm}$10 of the measured values. Best estimates of conductivity are considered to be ${\pm}$3 percent of the reported values. Resistivity measurements were made at six sites in carbonate sediments to a maximum depth of penetration of about 5 m. Average values of conductivity range between 0.88 and 1.21 mho/m. The results show the seabed is composed of alternating layers of relatively high-conductivity material (0.8 to 1.4 mho/m) in thicknesses of more or less one meter and layers about 30 cm thick having relatively low conductivities (0.4 to 0.8 mho/m).

• 한국환경과학회지
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• 제23권6호
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• pp.1165-1173
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• 2014

For the field application of dielectric barrier discharge plasma reactor in nutrient solution culture, a filtration-DBD (dielectric barrier discharge) plasma reactor was investigated for the Ralstonia solanacearum which causes bacterial wilt in aquiculture. The filtration-DBD plasma reactor system of this study was consisted of filter, plasma reactor, reservoir. The DBD plasma reactor consisted of a quartz dielectric tube, discharge electrode (inner) and ground electrode (outer). The experimental results showed that the inactivation of R. solanacearum with filter media type in filter reactor ranked in the following order: anthracite > fiber ball > sand > ceramic ball > quartz ceramic. In filtration + plasma process, disinfection effect with the voltage was found to small. In disinfection time of 120 minutes, residual R. solanacearum concentration was 1.17 log (15 CFU/mL). When the continuous disinfection time was 120 minute, disinfection effect was thought to keep the four days. In sporadic operation mode of 30 minutes disinfection - 24 hours break, residual R. solanacearum concentration after five days was 0.3 log (2 CFU/mL). It is considered that most of R. solanacearum has been inactivated substantially.

• 한국융합학회논문지
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• 제8권2호
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• pp.121-126
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• 2017

본 연구에서는 피부 등가모델을 통한 세포 내액과 세포 외액 성분의 생체임피던스 특성을 파악하기 위해 개발한 휴대용 소형 임피던스 측정시스템을 이용하여 4 전극법에 의한 비 침습 방식으로 다양한 주파수 대역에서 전신의 생체전기 임피던스를 측정실험을 수행하였다. 측정은 10명의 남성 피 실험자(평균 나이 $24{\pm}3.0$세, (BMI) $20.3kg/m^2$)를 대상으로 4주간 실시하였으며, 생체임피던스 다중주파수(1 kHz, 5 kHz, 50 kHz, 70 kHz, 100 kHz, 500 kHz)대역에서 측정하였다. 실험결과, 저주파 대역인 1 kHz 대역에서 임피던스가 가장 높게 측정되었고, 고주파 대역인 500 MHz에서 임피던스가 가장 낮게 측정되었다. 특히 50 kHz 대역이상에서 임피던스가 급속히 낮아짐을 실험을 통해서 확인하였다. 또한, 피부 등가회로모델을 통한 세포 내액과 세포 외액의 임피던스 특성을 파악하는 모의실험에서도 본 연구의 생체임피던스 측정시스템의 측정값과 유사한 특성이 얻어짐을 확인할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.198-201
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• 2012

연구는 근육의 기능을 조절하는 신경말단에 전기적인 자극을 가하여 신경의 반응 정도를 측정하는 플랫폼 구현에 관란 연구로써, 전기 자극에 대한 신경반응이 가해지는 전류량, 가해진느 전류지속시간, 전극위치에 따른 반응을 측정하였다. 신경자극의 전극 위치는 표면 말단에 운동신경이면 어느 신경이든지 가능하고, 신경자극 양식에는 단순연축자극(Single Twitch Stimulation), 사연속자극(Train-of-four, TOF), 두 집단 발사자극(Double Burst Stimulation, DBS)이 있다. 임베디드 시스템기반으로 가기위한 저전력 MCU를 선정하고, 기본적인 신경자극반응 측정 센서의 민감도를 알아보기 위해 센서 인터페이스를 구성하여 반응정도를 측정해야 한다. 그리고 측정된 Data의 정확도를 높이기 위해 고성능의 AD Convertor 선정하여 플랫폼을 구현하였다. 또한 본 논문의 플랫폼은 의료기기용으로 개발되었기 때문에 시스템 이용자의 안전을 고려하여 전원회로 구성 시 전원 Isolation를 고려하여 설계하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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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.

• Advances in materials Research
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• 제1권4호
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• pp.299-310
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• 2012

This article describes the synthesis of a novel N-substituted pyrrole monomer containing an azobenzene group. The 2-[N-ethyl-N-[4-[(4-nitrophenyl) azo]-phenyl] amino] ethyl-3-chloropropionate (RedII) compound was synthesized via reaction of 4-nitro-4'-[N-ethyl-N-(2-hydroxyethyl)-amino] azobenzene (RedI) and 3-chloropropionic acid. RedII was reacted with the potassium salt of pyrrole then 2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate (Py-RedII) was prepared. Chemical polymerization of Py-RedII and copolymerization of Py-RedII with pyrrole carried out using $FeCl_3$. Poly (2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate) (PPy-RedII) was characterized by UV, IR, $^1HNMR$, $^{13}CNMR$ spectroscopies. Electropolymerization of Py-RedII and electroco-polymerization of Py-RedII and pyrrole were studied using conventional three electrodes system, Ag/AgCl reference electrode, platinum counter electrode and GC disk working electrode. Scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) were used for thermal and rheological studies. The TGA curve of PPy-RedII demonstrated a high thermal stability up to 200°C and its DSC thermogram showed two endothermic peaks at 88 and $122^{\circ}C$. The glass transition temperature of the polymer was found to be above the room temperature. Electrical conductivities of PPy-RedII and it's copolymer with pyrrole (PPy-RedII-co-Py) were studied by the four-probe method and produced conductivities of $7.5{\times}10^{-4}$ and $6.5{\times}10^{-3}Scm^{-1}$, respectively.

• 항공우주시스템공학회지
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• 제13권2호
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• pp.19-25
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• 2019

구조물의 충격 위치 검출을 위해 본 연구그룹에서는 압전 페인트 센서를 연구하고 있다. 압전 페인트는 고주파 신호 및 충격에 민감한 특성으로 인하여 충격 감지에 사용할 수 있다. 또한, 압전 페인트 센서는 세라믹 센서가 적용될 수 없는 곡선 또는 복잡한 구조에 코팅될 수 있으며 외부 전원을 필요로 하지 않는다. 충격을 검출하기 위해 모자이크 패턴 전극을 시험편 위에 코팅하였고, 충격 신호는 충격이 발생한 전극부에서 얻을 수 있었다. 보다 더 정확한 충격 위치 검출을 위해서는 전극을 더 많은 부분으로 나누어 해당 전극부로부터 충격 데이터 수집이 필요하다. 본 연구에서는, 데이터 수집을 위하여 가볍고 저렴한 간단한 멀티채널 데이터 수집 시스템을 개발하였다. ARM Cortex-M3의 UART 통신을 이용하여 총 4채널의 데이터를 수집하였다.

• The Journal of Korean Physical Therapy
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• 제22권1호
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• pp.61-66
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• 2010

Purpose: The purpose of this study was to investigate the change in sympathetic nervous system responses of healthy adult women with changes in stimulus intensity of high frequency transcutaneous electrical nerve stimulation. Methods: Twenty-four healthy subjects (women) received high frequency electrical stimulation of the forearm. The subjects were randomly assigned to one of two groups; a low intensity stimulation group (n=12) and a high intensity stimulation group (n=12). The electrode attachment was arranged on the forearm of the dominant arm and the electricity stimulus time was 20 minutes. Measured items included skin conductance, pulse rate, skin temperature, and respiration rate. Each was measured at 4 times. Results: Skin conductance and skin temperature showed significant group by time interactions, though there were no significant group and time effects. There were no significant differences according to time, group effect, and a group by time interaction in pulse and respiration rates. Conclusion: High frequency and high intensity electrical stimulation may be helpful for the improvement of sudomotor function through the activation of the sympathetic nervous system. Also, high frequency and low intensity electrical stimulation may be helpful for the reduction of sudomotor function via inhibition of the sympathetic nervous system.