• Title/Summary/Keyword: Near-infrared Absorption

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The Quantitative Characterization of the Dispersion State of Single-Walled Carbon Nanotubes (단일벽 탄소나노튜브의 분산도 정량적 평가)

  • Yoon, Do-Kyung;Choi, Jae-Boong;Kim, Young-Jin;Baik, Seung-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.4
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    • pp.483-489
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    • 2007
  • We have investigated quantitative measurement techniques of the degree of dispersion of single-walled carbon nanotubes (SWNTs). SWNTs were suspended in aqueous media using a sodium dodecyl sulfate (SDS) surfactant. SWNTs with different dispersion states were prepared by controlling the intensity and time of sonication and centrifugation. The laser spectroscopic techniques were employed to characterize the dispersion state; i.e., raman fluorescence and absorption spectroscopic techniques. Raman spectroscopy has been used to probe the dispersion and aggregation state of SWNTs in solution. Individually suspended SWNTs show increased fluorescence peaks and decreased roping peaks at a raman shift 267 $cm^{-1}$ compared with the samples containing bundles of SWNTs. The ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectrum of decanted supernatant samples show sharp van Hove singularity peaks

Feasibility of near-infrared spectroscopic observation for traditional fermented soybean production (전통 메주 제조과정에 있어서 근적외 모니터링 가능성 조사)

  • Jeon, Jae Hwan;Lee, Seon Mi;Cho, Rae Kwang
    • Food Science and Preservation
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    • v.24 no.1
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    • pp.145-152
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    • 2017
  • In this study, near infrared (NIR) spectroscopy known as a non-destructive analysis technique was applied to investigate peptide cleavage and consequent release of amino acids in soybean lumps as affected by its moisture content and incubation time during fermentation at 25 for 3 weeks. The NIR spectra of the soybean lump semi-dried and soaked in saline water showed that absorption intensity around 1,400 nm originating from hydrogen bonds of water decreased and absorption band shifted to 1,430 nm as moisture content decreased during incubation at 25 for 3 weeks. In addition, absorption around 2,050 nm which was assigned to amino groups increased as incubation time increased. NIR spectra data from 1,000 to 2,250 nm showed higher accuracy in the discriminant analysis between outside and inside parts of fermented soybean lumps than visible spectra result. NIR spectroscopy for the amino acid and moisture contents in traditional fermented soybean lumps showed relatively good accuracy with the multiple correlation coefficient ($R^2$) of 0.91 and 0.81, respectively, and root mean square error of cross validation (RMSECv) of 0.23 and 0.83%, respectively, in partial least square regression (PLSR). These results indicate that NIR spectral observations could be applicable to control the fermentation process for preparation of soybean products.

DETERMINATION OF MOISTURE AND NITROGEN ON UNDRIED FORAGES BY NEAR INFRARED REFLECTANCE SPECTROSCOPY(NIRS)

  • Cozzolino, D.;Labandera, M.;Inia La Estanzuela
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1620-1620
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    • 2001
  • Forages, both grazed and conserved, provide the basis of ruminant production systems throughout the world. More than 90 per cent of the feed energy consumed by herbivorous animals world - wide were provided by forages. With such world - wide dependence on forages, the economic and nutritional necessity of been able to characterize them in a meaningful way is vital. The characterization of forages for productive animals is becoming important for several reasons. Relative to conventional laboratory procedures, Near Infrared Reflectance Spectroscopy (NIRS) offers advantages of simplicity, speed, reduced chemical waste, and more cost-effective prediction of product functionality. NIR spectroscopy represents a radical departure from conventional analytical methods, in that entire sample of forage is characterized in terms of its absorption properties in the near infrared region, rather than separate subsamples being treated with various chemicals to isolate specific components. This forces the analyst to abandon his/her traditional narrow focus on the sample (one analyte at a time) and to take a broader view of the relationship between components within the sample and between the sample and the population from which it comes. forage is usually analysed by NIRS in dry and ground presentation. Initial success of NIRS analysis of coarse forages suggest a need to better understand the potential for analysis of minimally processed samples. Preparation costs and possible compositional alterations could be reduced by samples presented to the instrument in undried and unground conditions. NIRS has gained widespread acceptance for the analysis of forage quality constituents on dry material, however little attention has been given to the use of NIRS for chemical determinations on undried and unground forages. Relatively few works reported the use of NIRS to determine quality parameters on undried materials, most of them on both grass and corn silage. Only two works have been found on the determination of quality parameters on fresh forages. The objectives of this paper were (1) to evaluate the use of NIRS for determination of nitrogen and moisture on undried and unground forage samples and (2) to explore two mathematical treatments and two NIR regions to predict chemical parameters on fresh forage. Four hundred forage samples (n: 400) were analysed in a NIRS 6500 instrument (NIR Systems, PA, USA) in reflectance mode. Two mathematical treatments were applied: 1,4,4,1 and 2,5,5,2. Predictive equations were developed using modified partial least squares (MPLS) with internal cross - validation. Coefficient of determination in calibration (${R^2}_{CAL}$) and standard error in cross-validation (SECV) for moisture were 0.92 (12.4) and 0.92 (12.4) for 1,4,4,1 and 2,5,5,2 respectively, on g $kg^{-1}$ dry weight. For crude protein NIRS calibration statistics yield a (${R^2}_{CAL}$) and (SECV) of 0.85 (19.8) and 0.85 (19.6) for 1,4,4,1 and 2,5,5,2 respectively, on a dry weight. It was concluded that NIRS is a suitable method to predict moisture and nitrogen on fresh forage without samples preparation.

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Measurement of Glucose concentration using Polarization Sensitive Low Coherence Interferometer (Polarization Sensitive Low Coherence Interferometer를 이용한 Glucose 농도 측정)

  • 이상원;김법민
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.128-129
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    • 2003
  • 최근 수년간 polarimetry, Raman spectroscopy, near infrared (NIR) absorption spectroscopy, NIR scattering, optoacoustics 등의 방법을 통하여 비침습적으로 Glucose의 농도를 측정하려는 연구가 많이 시도되었다. 일반적으로 이들 방법은 sensitivity 와 signal-to-noise ratio가 매우 낮고 복잡한 알고리즘이 요구되어져 glucose 농도 측정에 한계가 있음이 드러났다. 본 연구에서는 polarization sensitive optical coherence tomography (PS-OCT)에 사용되는 polarization sensitive low coherence inter-ferometer (PS-LCI) 기법을 이용하여 비침습적으로 glucose의 농도 측정을 가능하게 하는 시스템 개발에 중점을 두었다. (중략)

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Measurement of Stokes parameter changes due to blood glucose using PS-LCI (PS-LCI를 이용한 혈당 농도에 따른 Stokes 파라미터 측정)

  • 이상원;김법민
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.07a
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    • pp.258-259
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    • 2003
  • 최근 수년간 polarimetry, Raman spectroscopy, near infrared (NIR) absorption spectroscopy, NIR scattering, optoacoustics 등의 방법을 통하여 비침습적으로 Glucose의 농도를 측정하려는 연구가 많이 시도되었다. 일반적으로 이들 방법은 sensitivity 와 signal-to-noise ratio가 매우 낮고 복잡한 알고리즘이 요구되어져 glucose 농도 측정에 한계가 있음이 드러났다. 본 연구에서는 polarization sensitive low coherence interferometer (PS-LCI) 기법을 이용하여 농도에 따른 stokes parameters를 측정함으로써 비침습적으로 glucose를 측정하는 것이 가능한지 알아보는데 그 목적이 있다. (중략)

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Fundamental Investigation of Non-invasive Determination of Glucose by Near Infrared Spectrophotometry (근적외선 분광법을 이용한 비침투적 혈당 분석법 개발에 관한 기초 연구)

  • Kim, Hyo J.;Woo, Young A.;Chang, Soo H.;Cho, Chang H.;Cantrell, Kevin;Piepmeier, Edward H.
    • Analytical Science and Technology
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    • v.11 no.1
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    • pp.47-53
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    • 1998
  • This study is to improve the diagnosis of diabetes mellitus and the self-monitoring of blood glucose in people with diabetes by providing a non-invasive method of monitoring blood glucose. A near-infrared (NIR) spectrophotometer was used to measure absorption spectra of 80 glucose samples ranges from 1 mg/dL to 200 mg/dL, and shows the standard error of prediction 1.8 mg/dL. Also, to investigate the effect of interference in blood, NaCl and sand were added in glucose and found the standard error of prediction of 2.8 mg/dL and 3.8 mg/dL, respectively. A new and more accurate calibration system for the spectrophotometer was developed from systematic study of light scattering, which cause nonlinear spectrophotometer response.

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Quantitative Analysis on Near Band Edge Images in GaAs Wafer (GaAs 웨이퍼의 대역단 영상에 대한 정량적 해석)

  • Kang, Seong-jun;Na, Cheolhun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.5
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    • pp.861-868
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    • 2017
  • Near band infrared imaging technique has adopted for imaging EL2 and shallow level distributions in undoped semi-insulating LEC GaAs. This technique, which relies on the mapping of near bandgap infrared transmission, is both rapid and non-destructive. Until now no quantitative analysis has been reported for near band edge region which gives the reverse contrast on EL2 absorption images. This paper presents the spectral, spatial and temperature dependence of photoquenching forward and inverse mechanism in the band edge domain for cells and walls and for direct and inverted contrast conditions during transitory regimes. The difference in the threshold for the EL2w and EL2b defects could be attributed to the contribution of a different electrical assistance due to a different species of impurities. Quantitative analysis results show an increased density of EL2w and a small reduction of EL2b in the region of the walls where there is a high density of dislocations.

Non-destructive estimation of soluble solids in the intact melon fruits from cross progeny by non-contact mode with a fiber optic probe

  • Ito, Hidekazu;Fukino, Nobuko
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1524-1524
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    • 2001
  • A previous paper(Ito et al., 2000) has described the improvement of the standard error(SEC and SEP) of the predicted soluble solids(Brix) in a melon cultivar by non-contact mode with a fiber optic probe. Then we examined the immature and mature fruits. The objective of this study was to determine if non-contact mode could improve the standard error of the predicted Brix of matured melon fruits from cross progeny as well as the contact mode(usual method). The optical absorption spectrum was measured using a NIR Systems model 6500 spectrophotometer. A commercial spectral program(NSAS ver. 3.27) was used for multiple linear regression analysis. Absorbances of 902 and in the vicinity of 877 nm were included as the independent variables in both multiple regression equations. These wavelengths are key wavelengths for non-destructive Brix determination. When the results for the contact mode and non-contact mode are compared, the latter mode improved the former standard error(SEP and RMS).

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Development of a Transcutaneous Optical Information Transmission System for Total Artificial Heart Using Near Infrared Laser

  • Lee, Jung-Hoon;Kim, Wook-Eun;Choi, Jong-Hoon;Ahn, Jae-Mok;Min, Byoung-Goo
    • Proceedings of the KOSOMBE Conference
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    • v.1997 no.05
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    • pp.64-67
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    • 1997
  • In the total artificial heart(TAH), a transcutaneous information transmission system(TITS) is vely important to monitor the TAH status and detect the device failure, and repair the possible problems. First of all, the communication channel(skin) and method were simulated in terms of transmittance, scattering, reflection and absorption, then the system was designed with size reduction including low power consumption and reliability compared to the previous one. The informations are transmitted through the skin(approximately 1cm in depth) by frequency modulated near infrared(NIR) pulses using 780nm laser diodes as transmitters and photodiode as receiver with high speed and high spectral sensitivity. The logic high and low frequencies are 3MHz, 1MHz respectively. The system is a bidirectional data link for more than 38.4Kbps data rate, full-duplex with a bit error rate of less than $10^{-5}$.

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Characterization of Methanol-Water and Acetonitrile-Water Mixtures Using Iterative Target Transform Factor Analysis on Near Infrared Absorption Spectra (근적외선흡광스픽트럼에 대한 반복목표변환인자분석에 의한 메탄올-물 혼합액 및 아세토니트릴 -물 혼합액의 특성 확인)

  • 박영주;조정환
    • YAKHAK HOEJI
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    • v.48 no.1
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    • pp.6-12
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    • 2004
  • Near-infrared spectra of methanol-water mixtures and acetonitrile-water mixtures were acquired to find interactions between solvents widely used for reverse-phase liquid chromatography. Mixtures were prepared to give a series of increasing mole fractions of methanol or acetonitrile in water. Data matrices of acquired spectra were analyzed to determine the proper number of principal components of each mixture system using Malinowski's factor indicator function. Initial guess of score matrix and loading matrix were calculated by nonlinear iterative partial least squares (NIPALS) algorithm for faster computation. Iterative target transform factor analysis (ITTFA) was applied to convert the initial estimation of score matrix to true concentration profile and loading matrix to pure spectra of pure components of the mixtures. In case of methanol-water the number of principal components was found to be 4 and those initial guess of factors were converted to the pure spectra of water methanol and two kinds of complexes. In case of acetonitrile-water the number of pure components of the mixtures was found to be 3 and the pure spectrum of acetonitrile-water complex was found. The nonlinear characteristics of concentration profiles of complexes in the solvent mixtures may give a good criteria in understanding their elution characteristics in reverse-phase liquid chromatogrsphy.