• Journal of Biosystems Engineering
• /
• 제41권3호
• /
• pp.208-220
• /
• 2016

Purpose: Fusel oil is a potent volatile aroma compound found in many alcoholic beverages. At low concentrations, it makes an essential contribution to the flavor and aroma of fermented alcoholic beverages, while at high concentrations, it induced an off-flavor and is thought to cause undesirable side effects. In this work, we introduce Fourier transform near-infrared (FT-NIR) spectroscopy as a rapid and nondestructive technique for the quantitative determination of fusel oil in the Korean alcoholic beverage "soju". Methods: FT-NIR transmittance spectra in the 1000-2500 nm region were collected for 120 soju samples with fusel oil concentrations ranging from 0 to 1400 ppm. The calibration and validation data sets were designed using data from 75 and 45 samples, respectively. The net analyte signal (NAS) was used as a preprocessing method before the application of the partial least-square regression (PLSR) and principal component regression (PCR) methods for predicting fusel oil concentration. A novel variable selection method was adopted to determine the most informative spectral variables to minimize the effect of nonmodeled interferences. Finally, the efficiency of the developed technique was evaluated with two different validation sets. Results: The results revealed that the NAS-PLSR model with selected variables ($R^2_{\upsilon}=0.95$, RMSEV = 100ppm) did not outperform the NAS-PCR model (($R^2_{\upsilon}=0.97$, RMSEV = 7 8.9ppm). In addition, the NAS-PCR shows a better recovery for validation set 2 and a lower relative error for validation set 3 than the NAS-PLSR model. Conclusion: The experimental results indicate that the proposed technique could be an alternative to conventional methods for the quantitative determination of fusel oil in alcoholic beverages and has the potential for use in in-line process control.

• 분석과학
• /
• 제13권2호
• /
• pp.250-257
• /
• 2000

페인트, 섬유, 잉크 등은 범죄현장에 유류되는 많은 증거물 중 가장 빈번하게 접하게 되는 법과학 증거물로서 이들에 대한 분석 결과는 범죄현장과 피해자 또는 피의자, 피해자와 피의자간의 상황 재구성 및 인과관계, 도주 용의 차랑 등의 추적에 결정적인 역할을 하고 있다. 그러나 이들 시료는 육안으로 거의 확인이 되지 않을 만큼 극미량의 미세한 시료가 대부분이므로 법과학분야에서 미세시료에 대한 체계적인 분광학적 분석법이 대두되고 있다. 본 연구에서는 현미 자외/가시광선 현미분광광도계를 이용하여 섬유 14종, 국내 자동차 차체 페인트 2개 색상 44종 및 3개 회사의 컬러 프린트용 잉크로 인쇄한 4개 색상 12종에 대해 자외선/가시광선 영역(240-780nm)에서 투과 및 반사 측정법으로 측정하였으며, 각각 특징적인 흡수대로 섬유, 페인트 및 잉크의 이동식별이 가능하였다.

• 센서학회지
• /
• 제9권5호
• /
• pp.350-356
• /
• 2000

광출력이 크고, 방사선 손상이 작은 플라스틱 섬광체를 제작하기 위하여 제1용질 p-terphenyl과 제2용질 popop의 조성비에 따른 $^{60}Co$ $\gamma$-선에 대한 손상과 상대적 광출력을 조사하였다. $^{60}Co$ $\gamma$-선에 의한 손상은 주로 제2용질의 농도에 의존하였다. 발광스펙트럼의 파장범위는 $400{\sim}450\;nm$이고, 중심파장은 415 nm이었다. $^{60}Co$ $\gamma$-선의 조사량이 $1{\times}10^4\;Gy$까지는 방사선 손상에 의한 광투광율파 광출력 등이 변하지 않았다.

• Transactions on Electrical and Electronic Materials
• /
• 제13권6호
• /
• pp.310-316
• /
• 2012

A new method for early caries diagnosis was proposed and tested through a home-made optical examination system that used quantitative light fluorescence (QLF) and digital imaging fiber optic transillumination (FOTI) (DIFOTI), with light sources across a wide spectral range, from 350 nm to 1,000 nm. The front-illuminated infrared light scattering image (FIR) showed similar diagnostic abilities to that of DIFOTI. The FIR method was invented based on the observation that caries lesions lose the high transmittance and low scattering properties of benign enamel tissue. There are various methods for the early diagnosis of caries, such as visual examination, exploration, X-ray radiography, QLF, FOTI, and infrared fluorescence (diagnodent). Among them, methods based on optical properties are regarded as having the most potential. A comparative study was performed between the FOTI, QLF, diagnodent, optical coherence tomography, and FIR scattering image methods, using 20 extracted teeth samples with early caries. A scale of lesion measurement based on optical image contrast was proposed. The statistical analysis showed a significant correlation between the DIFOTI and FIR methods (r = 0.35, p < 0.05). However, the QLF and diagnodent methods showed little association with FIR images, as they have different detection principles as compared with FIR. Tomographic images obtained by OCT, using 1,330 nm super luminescent LED as a gold standard of tooth structure, verified that the FOTI and FIR results correctly represented the lack of homogeneity in dental tissue. The newly proposed FIR method attained similar diagnostic results to those of FOTI, but with an easier approach.

• 한국재료학회지
• /
• 제20권10호
• /
• pp.513-517
• /
• 2010

There have been many efforts to modify and improve the properties of functional thin films by hybridization with nano-sized materials. For the fabrication of electronic circuits, micro-patterning is a commonly used process. For photochemical metal-organic deposition, photoresist and dry etching are not necessary for microscale patterning. We obtained direct-patternable $SnO_2$ thin films using a photosensitive solution containing Ag nanoparticles and/or multi-wall carbon nanotubes (MWNTs). The optical transmittance of direct-patternable $SnO_2$ thin films decreased with introduction of nanomaterials due to optical absorption and optical scattering by Ag nanoparticles and MWNTs, respectively. The crystallinity of the $SnO_2$ thin films was not much affected by an incorporation of Ag nanoparticles and MWNTs. In the case of mixed incorporation with Ag nanoparticles and MWNTs, the sheet resistance of $SnO_2$ thin films decreased relative to incorporation of either single component. Valence band spectral analyses of the nano-hybridized $SnO_2$ thin films showed a relation between band structural change and electrical resistance. Direct-patterning of $SnO_2$ hybrid films with a line-width of 30 ${\mu}m$ was successfully performed without photoresist or dry etching. These results suggest that a micro-patterned system can be simply fabricated, and the electrical properties of $SnO_2$ films can be improved by incorporating Ag nanoparticles and MWNTs.

• 한국광학회지
• /
• 제31권3호
• /
• pp.148-154
• /
• 2020

본 논문에서는 주기적인 구멍배열(periodic hole array, PHA) 패턴을 가진 나노금속구조 컬러필터의 문제점인 입사광의 각도에 따른 컬러필터 중심파장의 이동을 해결하기 위해 새로운 구멍 패턴인 polyperiodic hole array (PPHA)를 제시한다. 먼저 녹색파장대역 컬러필터를 만들기 위해 구멍의 직경과 주기를 정했으며 propagation length와 skin depth를 고려해 단위셀의 크기, 금속과 유전체의 두께를 설정했다. PPHA 패턴을 만들기 위해 주기적인 구멍배열을 국부적으로 회전시켜 전체적으로는 비주기적이지만 부분적으로 주기적인 패턴을 만들었다. 그 결과 PHA 패턴과 대비하여 PPHA 패턴 나노금속구조 컬러필터는 입사광각이 0°에서 30°까지 증가하였을 때 파장의 이동도가 최대 40% 개선되었다. 본 연구를 통해 나노금속구조 컬러필터의 성능을 향상시킬 수 있으며 디스플레이, 이미지 센서 등 이미징 디바이스 분야에 접목시켜 산업적으로 활용할 수 있을 것으로 예상한다.

• 한국표면공학회지
• /
• 제53권1호
• /
• pp.9-14
• /
• 2020

CuS (copper sulfide) thin films having the same thickness of 100nm were deposited on the glass substrates using by radio frequency (RF) magnetron sputtering method. RF powers were applied as a process variable for the growth of CuS thin films. The structural and optical properties of CuS thin films deposited under different power conditions (40-100W) were studied. XRD analysis revealed that all CuS thin films had hexagonal crystal structure with the preferential growth of (110) planes. As the sputtering power increased, the relative intensity of the peak with respect to the (110) planes decreased. The peaks of the two bands (264cm^-1 and 474cm^-1) indicated in the Raman spectrum exactly matched the typical spectral values of the covellite (CuS). The size and shape of the grains constituting the surface of the CuS thin films deposited under the power condition ranging from 40W to 80W hardly changed. However, the spacing between crystal grains tended to increase in proportion to the increase in sputtering power. The maximum transmittance of CuS thin films grown at 40W to 80W ranged from 50 % to 51 % based on 580nm wavelength, and showed a relatively small decrease of 48% at 100W. The band gap energy of the CuS thin films decreased from 2.62eV (at 40W) to 2.56eV (at 100W) as the sputtering power increased.

• 생물환경조절학회지
• /
• 제10권3호
• /
• pp.141-147
• /
• 2001

주요 플라스틱 필름하우스 피복재의 광학 및 물리적 특성을 구명하고자 시설재배농가에서 일반적으로 이용하는 EVA(ethylene vinyl acetate, 0.08 mm) 필름을 비롯하여 기능성 피복재인 PO 방무필름(polyorefine antifog film. 0.1 mm), 불소필름(fluoric film, 0.06 mm), 산광필름(diffused film, 0.15 mm), PO 방적필름 (polyorefine antidrop film, 0.15 mm) 등과 경질 소재인 PET(polyethylene terephthalate, 0.5 mm)등 6종의 필름을 1997년에 폭 5.4m 길이 18.5m, 높이 2.9m의 소형 플라스틱필름 하우스에 각각 피복하고 3년간 (1997~1999) 필름들의 주요 특성을 조사하였다. 피복 후 30개월 경과시의 필름의 분광투과특성은 UV(300~400nm)가 산광 및 PET 필름에서 25~26% 밖에 투과되지 않은 반면, 불소필름에서는 76%, 기타 필름에서는 63~66% 투과되었다. PAR(광합성유효광, 400~700 nm)의 투과율은 불소(86.5%), 방적(80.5%), PET(76.3%), 방무(75.5%), EVA(74.1%), 산광필름(61.9%) 순으로 투과량이 많았다. 피복 후 7일경과 30개월경간의 PAR 투과율의 감소는 EVA가 12%로 가장 컸으며 방적필름이 6%로 가장 작았다. 토마토 작물군락하의 광도는 EVA 필름에 비해 산광필름에 비해 산광필름이 2.5배, 방적필름과 PET가 1.4배 각각 높았다. 필름의 인장저항력은 불소필름이 경질 소재이므로 월등히 강하였으며 다음으로 방적과 산광필름도 강한 경향이었다. 한편 충격저항력은 불소필름이 가장 약했고 방적과 산광필름은 강한 편이었다. 하우스내의 주간온도는 광투과율의 경향과 비슷하였으나, 야간온도는 PET, 불소, 방적, 산광, 방무, EVA 순으로 높았는데 특히 PET는 EVA보다 평균 4$^{\circ}C$ 높게 유지되었다. 하우스내로 투입된 일사량은 EVA 보다 불소필름 32%, 방적필름 15% PET 11%, 방무필름 4% 각각 많았는 반면, 산광필름은 7% 적었다.

• 한국근적외분광분석학회:학술대회논문집
• /
• 한국근적외분광분석학회 2001년도 NIR-2001
• /
• pp.1273-1273
• /
• 2001

The efficiency of the luminal fermentation process influences overall efficiency of luminal production, animal health and reproduction. Ruminant production systems have a significant impact on the global environment, as well. Animal wastes contribute to pollution of the environment as ammonia volatilized to the air and nitrate leached to ground water. Microbial protein synthesis in the rumen satisfies a large proportion of the protein requirements of animals. Quantifying the microbial synthesis is possible by using markers for lumen bacteria and protozoa such as nucleic acids, purine bases, some specific amino acids, or by isotopic $^{15}N,^{32}P,\;and\;^{35}S$ labelled feeds. All those methods require cannulated animals, they are time-consuming and some methods are very expensive as well. Many attempts have been made to find an alternative method for indirect measurement of microbial synthesis in intact animals. The present investigations aimed to assess possibilities of NIRS for prediction of purine nitrogen excretion and ruminal microbial nitrogen synthesis by NIR spectra of urine. Urine samples were collected from 12 growing sheep,6 of them male, and 6- female. The sheep were included in feeding experiment. The ration consisted of sorghum silage and protein supplements -70:30 on dry matter basis. The protein supplements were chosen to differ in protein degradability. The urine samples were collected daily in a vessel containing $60m{\ell}$ 10% sulphuric acid to reduce pH below 3 and diluted with tap water to 4 liters. Samples were stored in plastic bottles and frozen at $-20^{\circ}C$ until chemical and NIRS analysis. The urine samples were analyzed for purine derivates - allantoin, uric acid, xantine and hypoxantine content. Microbial nitrogen synthesis in the lumen was calculated according to Chen and Gomes, 1995. Transmittance urine spectra with sample thickness 1mm were obtained by NIR System 6500 spectrophotometer in the spectral range 1100-2500nm. The calibration was performed using ISI software and PLS regression, respectively. The following statistical results of NIRS calibration for prediction of purine derivatives and microbial protein synthesis were obtained.(Table Omitted). The result of estimation of purine nitrogen excretion and microbial protein synthesis by NIR spectra of urine showed accuracy, adequate for rapid evaluation of microbial protein synthesis for a large number of animals and different diets. The results indicate that the advantages of the NIRS technology can be extended into animal physiological studies. The fast and low cost NIRS analyses could be used with no significant loss of accuracy when microbial protein synthesis in the lumen and the microbial protein flow in the duodenum are to be assessed by NIRS.

• Journal of Biosystems Engineering
• /
• 제37권3호
• /
• pp.177-183
• /
• 2012

Purpose: In near infrared spectroscopy, interactance configuration of a light source and a spectrometer probe can provide more information regarding fruit internal attributes, compared to reflectance and transmittance configuration. However, there is no through study on the parameters of interactance measurement setup. The objective of this study was to investigate the effect of the parameters on the estimation of soluble solids content (SSC) and firmness of muskmelons. Methods: Melon samples were taken from greenhouses at three different harvesting seasons. The prediction models were developed at three distances of 2, 5, and 8 cm between the light source and the spectrometer probe, three measurement points of 2, 3, and 6 evenly distributed on each sample, and different number of fruit samples for calibration models. The performance of the models was compared. Results: In the test at the three distances, the best results were found at a 5 cm distance. The coefficient of determination ($R_{cv}{^2}$) values of the cross-validation were 0.717 (standard error of prediction, SEP=$1.16^{\circ}Brix$) and 0.504 (SEP=4.31 N) for the estimation of SSC and firmness, respectively. The minimum measurement point required to fully represent the spectral characteristics of each fruit sample was 3. The highest $R_{cv}{^2}$ values were 0.736 (SEP=$0.87^{\circ}Brix$) and 0.644 (SEP=4.16 N) for the estimation of SSC and firmness, respectively. The performance of the models began to be saturated when 60 fruit samples were used for developing calibration models. The highest $R_{cv}{^2}$ of 0.713 (SEP=$0.88^{\circ}Brix$) and 0.750 (SEP=3.30 N) for the estimation of SSC and firmness, respectively, were achieved. Conclusions: The performance of the prediction models was quite different according to the condition of interactance measurement setup. In designing a fruit grading machine with interactance configuration, the parameters for interactance measurement setup should be chosen carefully.