• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.79.3-79
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• 2002

$\textbullet$ Introduction $\textbullet$ Structure of variable multi-valued spatial filter detector(VMSFD) $\textbullet$ Moment analysis by VMSFD $\textbullet$ Experimental results $\textbullet$ Fabricated chip with photodiode array $\textbullet$ Conclusion

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.568-574
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• 2000

Phytofluene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector. Phytofluene was solubilized in 5% tween 40, and then oxidized by incubating under dim yellow light at 37$^{\circ}C$, 24 hr with continuous shaking. Carbonyl compound and acidic compound were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra were identical to the reference cleavage products prepared by ozeonolysis of phytofluene. Absorption spectrum of acidic compound was similar to that of standard 4,5-didehydrogeranyl geranyl acid which is known to possess biological activity. Thus, eccentric cleavage of phytofluene was confirmed to occur in vitro under oxidation condition.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1227-1233
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• 2000

Lycopene was subjected to ozonolysis in ice-cold dichloromethane. The ozonolysis products were fractionated with a silica column and the carbonyl fraction was analyzed by ODS-HPLC with a photodiode array detector and by LC-MS. UV-vis spectra and $[M+H]^+$ of the carbonyl compound peaks showed clearly that acycloretinal, apo-14'-lycopenal, apo-12'-lycopenal, apo-10'-lycopenal, apo-8'-lycopenal and apo-6'-lycopenal were formed by ozonolysis of lycopene. Lycopene was solubilized in toluene and aqueous Tween 40, and then oxidized by incubating at $37^{\circ}C$ under atmospheric oxygen. Carbonyl compounds were produced. In comparison with autoxidation and ozonolysis, each compound showed the same retention time and UV-vis spectra are identical to the reference cleavage products prepared by ozonolysis of lycopene. Thus, eccentric cleavage of lycopene was confirmed to occur in vitro under oxidation condition.

• Analytical Science and Technology
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• v.34 no.4
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• pp.172-179
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• 2021

Oleanane-type triterpenoids exist as secondary metabolites in various plants. In particular, soyasaponin, an oleanane-type triterpenoid, is abundant in the hypocotyl of soybean, one of the most widely cultivated crops in the world. Depending on their chemical structure, soyasaponins are categorized as group A saponins or group DDMP (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one) saponins. The different soyasaponin chemical structures present different health functionalities and taste characteristics. However, conventional phenotype screening of soybean requires a substantial amount of time for functionality of soyasaponins. Therefore, we attempted to use liquid chromatography with a photodiode array detector and tandem mass spectrometry (LC-PDA/MS/MS) for accurately predicting the phenotype and chemical structure of soyasaponins in the hypocotyl of five common soybean natural mutants. In this method, the aglycones (soyasapogenol A [SS-A] and soyasapogenol B [SS-B]) were detected after acid hydrolysis. These results indicated that the base peak and fragmentation differ depending on the chemical structure of soyasaponin with aglycone. Thus, a fragmentation database can help predict the chemical structure of soyasaponins in soyfoods and plants.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.67-72
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• 2023

A simple and accurate method was developed for the quantitative analysis of oleanonic acid (OA) from mastic gum. The analysis was carried out using reverse-phase high-performance liquid chromatography combined with a photodiode array detector (HPLC/PDA). Our optimized method was validated by measuring various parameters, using an INNO C18 column fitted with a gradient elution system. The results revealed limits of detection and quantification of 0.34 and 1.042 ㎍/mL, respectively. The OA calibration curve exhibited excellent linearity over the concentration range of 0.0625 to 2.0 mg/mL, with r² =0.9996. Accuracy tests revealed a high recovery rate of 99.44-103.66%, with precision values below 0.15%. These results suggest that the present analytical method can identify and quantify OA in mastic gum with high precision. The HPLC approach developed in this study might be applied to routine analyses and large-scale extraction procedures for OA content quantification.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.32-32
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• 2008

X-ray detector는 의료용, 산업용 등 다양한 분야에서 사용되어지고 있으며 기존의 Analog X-ray 방식의 환경오염, 저장공간 부족, 실시간 분석의 어려움 등의 문제점들을 해결하기 위하여 Digital X-ray로의 전환과 연구가 활발하며 이에 따른 관심도 높아지고 있는 살점이다. Digital X-ray detector는 p-영역과 n-영역 사이에 아무런 불순물을 도핑하지 않은 진성반도체(intrinsic semiconductor) 층을 접합시킨 이종접합 PIN 구조의 photodiode 이다. 이 소자는 역바이어스를 가해주면 p영역과 n영역 사이에서 캐리어 (carrier)가 존재하지 않는 공핍 영역이 발생하게 된다. 이런 공핍 영역에서 광흡수가 일어나면, 전자-정공 쌍이 발생한다. 그리고, 발생한 전자-정공 쌍에 전압이 역방향으로 인가되는 경우, 전자는 양의 전극으로 이동하고, 정공은 음의 전극으로 이동한다. 이와 같이, 발생한 캐리어들을 검출하여 전기적인 신호로 변환 시킨다. 고해상도의 Digital X-ray detector를 만들기 위해서는 누설전류에 의한 noise 감소와 소자의 높은 안정성과 내구성을 위한 높은 breakdown voltage를 가져야 한다. 본 연구에서는 Digital X-ray detector의 leakage current 감소와 breakdown voltage를 높이기 위하여 guradring과 gettering technology를 사용하여 전기적 특성을 분석하였다. 기판으로는 $10k\Omega{\cdot}cm$ resistivity를 갖으며, n-type <111>인 1mm 두께의 4인치 Si wafer를 사용하였다. 그리고 pixel pitch는 $100{\mu}m$이며 active area는 $80{\mu}m{\times}80{\mu}m$인 $32\times32$ array를 형성하여 X-ray를 조사하여 소자의 특성을 평가 하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.10-17
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• 2009

Transillumination system used by radiation is widely applied to industrial imaging system. In this study, the linear detector array constructed with scintillator and pin diode, and a multi-channel data acquisition system was developed for precision inspection of end-milling. The detector module consists of $16-CdWO_4$crystal scintillator and photodiode array. The detector and data acquisition system was applied to precision inspection of end-mill and the images of the end-mill were successfully reconstructed. The total system can analyze the Detector Quantum Efficiency(DQE) of each system. The performance of developed photodiodes equipment was compared with each other for different crystal geometry and its characteristics. Finally fine details of the end-mill phantom were constructed for industrial application. The image acquired contains several objects on a real time data transfer and the linear X-ray scanning system can be applied to many fields of a industry.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.921-926
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• 2003

This paper describes a new type of the spatial filter detector (SFD) with variable and multi-valued weighting function. This SFD called variable spatial filter detector with multi-valued weighting function (VSFDwMWF) uses current-mode circuits for noise resistance and high-resolution weighting values. Total weighting values consist of 7bit, 6-signal bit and 1-sign bit. We fabricate VSFDwMWF chip using Rohm 0.35${\mu}$m CMOS process. VSFDwMWF chip includes two-dimensional 10${\times}$13 photodiode array and current-mode weighting control circuit. Simulation shows the weighting values are varied and multi-valued by external switching operation. The layout of VSFDwMWF chip is shown.

• Journal of the Semiconductor & Display Technology
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• v.17 no.2
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• pp.12-15
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• 2018

InSb (III-V compound semiconductor) is used for photodiode to detect the mid-wavelength infrared radiation. Generally the quantum efficiency of InSb IR FPAs(Focal Plane Arrays) is known to be determined by thickness of InSb and transmittance of anti-reflection coating layer. In this study, we confirmed that the C-V characteristics of detector array affects the quantum efficiency of the InSb IR FPAs. We fabricated the IR FPAs with various $V_{fb}$(flat band voltage) values and confirmed the tendency between the $V_{fb}$ value and quantum efficiency of the IR FPAs.

• Analytical Science and Technology
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• v.13 no.3
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• pp.282-290
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• 2000

In this study, polymer additives were extracted and separated by Soxhlet extraction method and the dissolution-precipitation method from a polycarbonate (optical grade) which completely absorbed UV light below 390 nm. Analytical techniques such as UV-Vis spectroscopy, FT-IR, and HPLC were applied to analyze additives in polycarbonate. Separated materials from the polycarbonate may be a complex mixture containing additives such as UV stabilizer, antioxidants (primary and secondary), monomers, and oligomers. Several compounds such as bisphenol A, Irganox 1010, and Cyasorb UV-5411 were identified by chromatograms and UV spectra obtained from RP HPLC analysis using Bondapak $C_{18}$ column, methanol mobile phase, and a photodiode array (PDA) detector. Also, the content of UV-5411 in the polycarbonate was about 0.12 wt% by a quantitative analysis through UV spectroscopy.