• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.55-61
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• 2022

There is a major interest in diagnostic technology for multiple cancers worldwide. In order to reduce the difficulty of cancer diagnosis, a liquid biopsy technology based on a microfluidic device using trace amounts of biofluids such as blood is being studied. And optical biosensing, which measures the concentration of analytes through fluorescence imaging using biofluids, requires various strategies to improve sensitivity, and specialists and equipment are needed to carry out these strategies. This leads to an increase in diagnostic and production costs, and it is necessary to develop a technology to solve this problem. In this paper, we design and propose a fluorescent multi-cancer diagnostic sensing platform structure that implements passive self-separation technology and molecular recognition activation functions by fluid mixing, only with the geometry and microfluidic phenomena of microchannels based on self-driven flow by capillary force. In order to check the parameters affecting the performance of the plasma separation part of the designed sensor, the hydrodynamic diameter of the channel and the viscosity of the fluid were set as variables to confirm the formation of plasma separation flow through simulation. And finally, we propose an optimal sensor platform structure.

• Journal of Sensor Science and Technology
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• v.6 no.1
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• pp.16-23
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• 1997

Bismuth germanate crystals well known as scintillator were grown by Czochralski method. In order to understand a mechanism of radiation resistance in Eu-doped BGO, we measured radiation induced-absorption spectra, excitation spectra, emission spectra and luminescence lifetimes of BGO crystals. We found that the charge transfer state of $Eu^{3+}$ ion is to play a key role to enhance the radiation resistance in BGO crystal. The $^{5}D_{0}$ emission of $Eu^{3+}$ ions that is not suitable for the radiation detectors due to a long decay time was found to be increased with increasing europium concentration. In the BGO crystal doped with 0.1 mole%, the density of radiation induced color centers was reduced about twenty times and the light output of $^{5}D_{0}$ was negligible by comparing to that of BGO.

• Journal of Sensor Science and Technology
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• v.11 no.5
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• pp.301-308
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• 2002

BaFBr:$Eu^{2+}$ phosphors were prepared, and the thermoluminescence(TL) and photostimulated luminescence(PSL) of the prepared phosphors were measured. Two glow peaks around 352 and 448 K are observed for x-ray irradiated BaFBr:$Eu^{2+}$ phosphors, and the activation energy of the main glow peak(352 K) was about 0.96 eV. The spectral range of the PSL was $350{\sim}450\;nm$, and the activation energy of the trap giving rise to PSL was about 0.98 eV. The activation energy of the traps giving rise to TL is agreed to those giving rise to PSL within experimental error.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.11-15
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• 1994

The TSEE characteristics of LiF(Mg,Cu,Na,Si)phosphor for gamma and beta rays are described. The TSEE glow curve of this phosphor showed 5 peaks in the range from $20^{\circ}C$ to $400^{\circ}C$ and its main peak appeared at $240^{\circ}C$. The sensitivity of the phospor for $^{60}Co$ gamma rays was about 450counts/mR. TSEE energy dependence for various beta radiation was nearly constant (${\pm}10%$) in the mean beta particle energy range from 0.02MeV to 0.8MeV. The efficiency of TSEE of the phosphor for beta radiation was $(2{\sim}15){\times}10^{-3}$.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.313-318
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• 1998

The thermal annealing, reusability and fading characteristics of the highly sensitive LiF:Mg,Cu,P TLDs are investigated. Thermoluminescent sensitivity of the fabricated LiF:Mg,Cu,P TLD is 25.3 times higher than the commercial dosimeter TLD-700(Harshaw Chemical Co.). The main dosimetric peak shows no fading for 1 month at room temperature and 50% for 7 days at $100^{\circ}C$. The thermal annealing characteristics is examined in the temperature range from $260^{\circ}C$ to $320^{\circ}C$. For annealing the TLD at $280^{\circ}C$ for 10 minutes, TLDs can be reusable by recovering the initial sensitivity.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.250-252
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• 2004

나노 기술의 개발과 마이크로어레이(microarray)의 등장으로 생물학자동을 한번에 보다 라르고 신속하게, 대량의 실험을 처리할 수 있게 되었다. 이와 발 맞추어 마이크로어레이를 이용한 다양한 실험 방법들이 개발되었다. 형광 염료(fluorescence dye)를 이 용한 관찰 방법 이 널리 이용되고 있으나, 관찰되는 형광 염료의 밝기가 실험 환경(pH, 온도)에 매우 민감하게 반응하며, 단백질을 포함한 많은 분자 물질들이 형광을 내지 않기 때문에 마이크로어레이를 이용한 분석 대상 물질들의 개수가 제한을 받는다. 본 논문에서는 직접적인 형광 염료의 사용 없이, SPR(Surface Plasmon Resonance)을 이용한 마이크로어레이 분석 시스템에서 스팟(spot)의 밝기(intensity)를 측정하기 위한 효율적인 전처리 과정을 제안하고자 한다. 전처리 과정은 크게 프로젝티브 왜곡 효과 제거, 스팟의 위치 추적, 스팟의 영역 추출, 정규화 된 스팟의 밝기 측정으로 나누어진다. 특히, 이러한 과정을 거쳐서 측정된 밝기는 반응 유무의 관찰뿐만이 아니라, 실험 물질의 양적인 측정에도 이용되기 때문에 정확한 스팟의 밝기 측정에 중점을 두고자 한다.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.19-26
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• 2013

In this paper, we present a novel illumination system for parking lots constructed underground. We design and implement this system using microwave sensors and dimming control of LED fluorescent lamps so that we can obtain lighting efficiency of the illumination scheme. We construct an effective illumination system in the aspects of performance and cost, resulting in energy-saving and electricity reduction. Recently conventional energy-saving method applied to old underground parking lots mainly relies upon turning off the half of total number of lamps installed in the parking lot. Sometimes there are some lots that have infrared sensor to be used to turn on/off the fluorescent lamps to realize these operations smoothing. The other schemes utilize timer to control lighting time of the fluorescent lamps. These conventional schemes are forcing to turn off a part of lamps installed so that we cannot apply them in a systematic way. Moreover they will be most inefficient when we leave them alone to be continuous consumers. The lighting control system proposed in this paper can recognize objects through microwave sensors and inform the appropriate lighting time, furthermore we can adjust brightness of LED lamps following the surroundings using dimming control scheme so that we can epochally improve the illumination system for underground parking lots. According to our sophisticated test experiments, we can maximally obtain 81.9% of energy-saving effectiveness using the system proposed in this paper.

• Polymer Science and Technology
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• v.26 no.4
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• pp.282-289
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• 2015

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.232-234
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• 2002

Bacillus cereus secretes a nonspecific phospholipase C (PLC) that catalyzes the hydrolysis of phospholipids to yield diacylglycerol and a phosphate monoester. This study focuses on the production of PLC by B. cereus and recombinant E. coli with fusion protein gene (plc::gfp). Fermentation processes have been monitored by a 2-dimensional fluorescence sensor.

• Journal of Sensor Science and Technology
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• v.6 no.1
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• pp.35-42
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• 1997

The optical biosensor using the electrically controlled release of reactive reagent is developed for the detection of peroxide. Rapid degradation of polymer complex of PEOx and PMAA occurs as the applied current increases and thus released amount of HPA increases. The degradation velocity of polymer and the amount of HPA released are linearly proportional to the applied current. Peroxide is reacted with the released reagent by peroxidase and then the product, a fluorescent dimer DBDA, is formed. The monochromic light from light source (150W Xe arc ramp) excites the DBDA and the excited light is transmitted through an optical fiber to be detected by a photodiode array. The change of fluorescence intensity is related to the change of peroxide concentration. The peroxidase is entrapped in Ca-alginate get on the inner surface. The biosensor has the linear signal range of 0.025mM-10.mM peroxide. By applying the step function of peroxide, reproducibility of biosensor has been investigated. The mathematical model is constructed by the combination of enzyme kinetics with reactor flow model. Good agreement is obtained between the experimental result and model prediction in the sensor signal.