• 센서학회지
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• 제15권3호
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• pp.158-163
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• 2006

This paper reports a novel immunoassay method using superparamagnetic nanoparticles and an enhanced magnetic field gradient for the detection of protein in a microfluidic device. We use superparamagnetic nanoparticles as a label and fluorescent polystyrene beads as a solid support. Based on this platform, magnetic force-based microfluidic immunoassay is successfully applied to analyze the concentration of IgG as model analytes. In addition, we present ferromagnetic microstructure connected with a permanent magnet to increase magnetic flux density gradient (dB/dx, ${\sim}10^{4}$ T/m), which makes limit of detection reduced. The detection limit is reduced to about 1 pg/mL.

• 전기학회논문지
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• 제57권11호
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• pp.2006-2010
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• 2008

In this paper, we fabricated a biosensor for detecting hydrogen peroxide and investigated the sensing property. We prepared a viologen and hemoglobin modified gold electrode using self-assembly and layer by layer method. The electrochemical property of the viologen derivative was characterized in 0.1 M $NaClO_4$ electrolyte solution by cyclic voltammetry. The modified electrode showed reversible electrochemical properties and high stability. From the results, the viologen can act as a charge transfer mediator for access to the electrode surface. The catalytic characteristics of the designed sensor proved that hemoglobin has been kept in its natural structure and can retain its biological activity. The designed biosensor showed a fast amperometric response, excellent linearity and low detection limit. In addition, it had high sensitivity, good reproducibility and stability.

• 한국환경과학회지
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• 제21권11호
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• pp.1333-1338
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• 2012

In order to measure the minute amount of Cu(II) in our environment, cyclic voltammetry (CV) and square-wave stripping voltammetry (SWSV) were performed for a trace copper assay using bismuth immobilized on a carbon nanotube paste electrode. An analytical working range of 30 to $240{\mu}g/L$ Cu(II) was obtained for CV and SWSV. The SWSV precision obtained was 0.47 % (n = 15) RSD in $30.0{\mu}g/L$ Cu(II). The detection limit obtained was 3.1 ng/L Cu(II) using SWSV, while the CV yielded the nano-range detection limit through the pre-concentration step. By using this research method, Cu(II) value could be determined in the urine of human sample and in the brain of fish sample. This research can be effectively applied to other cases of measuring minute amount of Cu(II) in living organisms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1360-1363
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• 1996

EPD(End Point Detection) is used to decide etching degree of layer which must be removed at wafer etching process in plasma etching process which is one of the most important process in semiconductor manufacturing. In this thesis, the method which detects malfunction of etching process in real-time will be discussed. Several EPD signal traces are collected in normal plasma etching condition and used as reference EPD signal traces. Critical points can be detected by applying differentiation and zero-crossing techniques to reference EPD signal. Mean and standard deviation of critical parameters which is memorized from reference EPD signal are calculated and these determine the lower and higher limit of control chart. And by applying statical control chart to EPD signals which are collected in real etching process malfunctions of process are detected in real-time. By means of applying this method to the real etching process we prove our method can accurately detect the malfunction of etching process and can compensate disadvantage of current industrial method.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.100-108
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• 2011

A method for the rapid detection and quantification of Newcastle disease virus (NDV) produced in an animal cell culture-based production system was developed to enhance the speed of the NDV vaccine manufacturing process. A SYBR Green I-based real-time RT-PCR was designed with a conventional, inexpensive RT-PCR kit targeting the F gene of the NDV LaSota strain. The method developed in this study was validated for specificity, accuracy, precision, linearity, limit of detection (LOD), limit of quantification (LOQ), and robustness. The validation results satisfied the predetermined acceptance criteria. The validated method was used to quantify virus samples produced in an animal cell culture-based production system. The method was able to quantify the NDV samples from mid- or late-production phases, but not effective on samples from the early-production phase. For comparison with other quantifiable methods, immunoblotting, plaque assay, and tissue culture infectious dose 50 ($TCID_{50}$) assay were also performed with the NDV samples. The results demonstrated that the real-time RT-PCR method is suitable for the rapid quantification of virus particles produced in an animal cell-culture-based production system irrespective of viral infectivity.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.308-311
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• 2005

[ $^{222}Rn\;and\;^{226}Ra$ ] in groundwater were determined simultaneously using a gamma-spectroscopy. A nitrogen flushing equipment has been used for elimination and stabilization of high and unstable background activity due to the radon and its progenies in counting shield and room. The aim of present work was to control the background activity for simultaneous measurement of radium$(^{226}Ra)$ and radon$(^{222}Rn)$ in groundwater using a gamma-spectrometry. Background activity was about 1.0dps and the standard deviation was about 50%, The background activity could be minimized using nitrogen flushing equipment in the range of 0.1 to 0.5 and the RSD was about 5% at the experimental condition. The detection limit of $^{222}Rn\;and\;^{226}Ra$ in groundwater was 0.5dps/L in the background control method. In most groundwater used in the work, radon activity was more than the detection limit. However, radium activity in some groundwater was less than the detection limit. If the low level radium in groundwater must be measured, preconcentration process such as concentration should be performed before measuring the groundwater.

• Journal of Power Electronics
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• 제7권1호
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• pp.64-71
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• 2007

This paper proposes a novel active frequency drift (AFD) method to improve the islanding detection performance with minimum current harmonics. To detect the islanding phenomenon of grid-connected photovoltaic (PV) inverters concerning the safety hazards and possible damage to other electric equipment, anti-islanding methods have been described. The AFD method that uses chopping fraction (cf) enables the islanding detection to drift up (or down) the frequency of the voltage during the islanding situation. However, the performance of the conventional AFD method is inefficient and causes difficulty in designing the appropriate cf value to meet the limit of harmonics. In this paper, the periodic chopping fraction based on a novel AFD method is proposed. This proposed method shows the analytical design value of cf to meet the test procedure of IEEE Std. 929-2000 with power quality and islanding detection time. To verify the validation of the proposed method, the islanding test results are presented. It is confirmed that the proposed method has not only less harmonic distortion but also better performance of islanding detection compared with the conventional AFD method.

• 한국식품위생안전성학회지
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• 제3권2호
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• pp.65-73
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• 1988

종래의 화학적, 생물학적 분석방법의 단점인 검출한도가 낮은점, 시료전처리의 복잡성, 비경제성 및 비 특이성 등을 극복하기 위해 monoclonal AB를 사용한 ELISA법으로 T-2 toxin 에 대해 특이성있는 새로운 분석법을 개발하여 다음과 같은 결과를 얻었다. 1. 종래의 GLC 및 GC-MS 분석법보다 간편하고 신뢰성이 높으며 검출한계가 0.1ppb인 고감도의 분석법을 개발하였다. 2. 본 분석법을 이용하여 Fusarium spp. 균의 T-2 생산유무를 단시간에 다량의 시료를 검색할 수 있었으며, data의 정확도가 GLC와 유사하며 GLC로는 검색할 수 없는 150ppb이하의 미량함유 시료에서도 T-2 toxin을 검색할 수 있었다. 3. 본 실험에 사용한 F. sporotichioides M-1-1 균주의 밀에 대한 최적 배양조건은 $24~27^{\circ}C$ 2주간임을 알았다.

• Journal of Mechanical Science and Technology
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• 제18권11호
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• pp.1961-1968
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• 2004

The design of a reliable and failsafe control system requires that sensor failures be detected and identified within acceptable time limit so that system malfunction can be prevented. This paper presents a model-based approach to sensor fault detection with applications to vehicle stability control systems. The effectiveness of the proposed method is illustrated through test data-based evaluation. Vehicle test data-based evaluation results show that the proposed fault management scheme can be used for the design of a failsafe VSCs.

• ALGAE
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• 제28권3호
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• pp.289-296
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• 2013

For the quantitative detection of algal toxin, microcystin, a chemiluminescence immunochromatographic assay method was developed. The developed system consists of four parts, chemiluminescence assay strip (nitrocellulose membrane), horse radish peroxidase labeled microcystin monoclonal antibodies, chemiluminescence substrate (luminol and hydrogen peroxide), and luminometer. The performance of the chemiluminescence immunochromatographic assay system was compared with high performance liquid chromatography (HPLC) detection. The detection limit of chemiluminescence immunochromatographic assay system is several orders of magnitude lower than with HPLC. The chemiluminescence immunochromatography and HPLC results correlated very well with the correlation coefficient ($r^2$) of 0.979.