• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1022-1022
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• 2001

To obtain accurate and repeatable analyses using NIR technology it is important to select an NIR instrument and / or its sample presentation attachments which allow the operator to minimize sampling errors without compromising the benefits of NIR analysis -namely rapid, low cost, minimal sample preparation, minimal structural facilities, minimal hazards. For each sample type and consistency there may be different optimal combinations of instrument, sample presentation attachment, and sample preparation. This paper will consider options available to NIR users in the area of plant and soil analysis and evaluate the potential benefits and disadvantages of crop nutrient diagnoses using laboratory based and airborne imaging techniques.

• Near Infrared Analysis
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• 제1권2호
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• pp.21-27
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• 2000

Temperature-dependent changes in near-infrared (NIR) spectra have been measured for oleic acid, and nonanoic acid in the pure liquid state. Particular attention has been paid to the 5400-4800 cm$\^$-1/ region where a number of combination bands appear. The NIR spectra of oleic acid show that a band at 5303 cm$\^$-1/ increases with temperature while that at 5270 cm/sup-1/ decreases. It ha been found from their second derivative spectra that these spectral changes take place stepwisely with two break points at 30 and 53$\^{C}$, which correspond to the phase transition temperatures oleic acid reported previously. Principle component analysis (PCA) has been carried out for the NIR spectra of oleic acid in the 5400-4800 cm$\^$-1/ region measured over a temperature range of 15-80$\^{C}$. core plots of the first and second principal components (PCs) show that the NIR spectra are classified into three groups; the spectra measured in the temperature range of 15-30$\^{C}$, those in the range of 31-53$\^{C}$, and those in the range of 54-80$\^{C}$. These temperature ranges correspond to those for quasi-smectic liquid crystal, disordered liquid crystal, and isotropic liquid of oleic acid in the pure liquid state. In other words, PCA provides unambiguous evidence for the phase transitions. similar studies have been carried out for petroselinic acid and nonanoic acid in the pure liquid states, but they do not show any evidence for phase transitions.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1614-1614
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• 2001

The sweetness (。Bix) of fruit is the main quality factor contributing to the fruit taste. The brix of the apple fruit can be measured non-destructively by near infrared (NIR) spectroscopy, allowing the sweetness grading of individual apple fruit. However, the fruit quality is influenced by various factors such as growing location, producing year, variety and harvest time etc., accordingly the robust NIR calibration is required. In this experimental results are presented the influence of two variations such as growing location and producing year of apple fruit in establishing of calibrations for sweetness, and developed a stable and highly accurate calibration. Apple fruit (Fuji) was collected every year from 1995 to 1997 in 3 different growing locations (Andong, Youngchun and Chungsong) of Kyungpook in Korea. NIR reflectance spectra of apple fruit were scanned in wavelength range of 1100∼2500nm using an InfraAlyzer 500C (Bran+Luebbe) with halogen lamp and PbS detector. The multiple linear regression and stepwise was carried out between the NIR raw spectra and the brix measured by refractometer to select the best regression equations. The calibration models by each growing district were well predicted to dependent sample set, but poorly predicted to independent sample set. Combined calibration model using data of three growing districts predicted reasonable well to a population set drawn from all growing districts(SEP = 0.69%, Bias=-0.075). The calibration models by each harvest year were not transferable across harvest year, however a combined calibration model using data of three harvest years was sufficiently robust to predict each sample sets(SEP = 0.53%, Bias = 0.004).

• 한국토양비료학회지
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• 제47권5호
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• pp.319-323
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• 2014

This study investigates the prediction of soil chemical properties (organic matter (OM), pH, Ca, Mg, K, Na, total acidity, cation exchange capacity (CEC)) on 688 Korean soil samples using the visible-near infrared reflectance (VIS-NIR) spectroscopy. Reflectance from the visible to near-infrared spectrum (350 to 2500 nm) was acquired using the ASD Field Spec Pro. A total of 688 soil samples from 168 soil profiles were collected from 2009 to 2011. The spectra were resampled to 10 nm spacing and converted to the 1st derivative of absorbance (log (1/R)), which was used for predicting soil chemical properties. Principal components analysis (PCA), partial least squares regression (PLSR) and regression rules model (Cubist) were applied to predict soil chemical properties. The regression rules model (Cubist) showed the best results among these, with lower error on the calibration data. For quantitatively determining OM, total acidity, CEC, a VIS-NIR spectroscopy could be used as a routine method if the estimation quality is more improved.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1623-1623
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• 2001

Composting is a biological method used to transform the organic waste into stable, humified organic amendments. Humification is indicated as the key factor in improving the quality of compost, because of the importance of humic substances to soil ecology, fertility and structure, and their beneficial effects on plant growth The compost constituents vary widely, however, the degree of maturity is very important factor in compost quality. So this experiment carried out to determine the rapid estimation of the quality in cattle, pig, chicken and waste composts using near infrared reflectance spectroscopy(NIRS). Near infrared reflectance spectra of composts was obtained by Infra Alyzer 500 scanning spectrophotometer at 2-nm intervals from 1100 to 2500nm. Multiple linear regression(MLR) or partial least square regression (PLSR) was used to evaluate a NIRS method for the rapid and nondestructive determination of humic acid contents in composts. The results summarized that NIR spectroscopy can be used as a routine testing method to determine quantitatively the humic acid content in the compost samples ondestructively. Especially, we supposed that absorbance around 2300nm is related to humic acid as a factor of compost maturity. However the NIR absorption approach is empirical, it actually requires many combinations of samples and data manipulations to obtain optimal prediction.

• 한국토양비료학회지
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• 제33권4호
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• pp.242-246
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• 2000

근적외 분광분석기를 이용하여 과수의 영양진단을 위한 신속한 엽분석 수단으로 활용하고자 본 시험을 수행하였다. 사과 '후지'품종 잎 177점, 포도 '캠벨얼리' 품종 잎130점의 시료를 이용하여 1,100~2.500nm까지 근적외영역의 흡수스펙트럼을 측정하였다. 총질소 분석은 살리실산-황산으로 분해후 켈달 증류하여 측정하였다. 근적외 스펙트럼과 총 질소함량과의 상관분석을 이용, 검량식을 개발하였고 화학분석한 결과에 대한 예측식을 구하였다. 사과는 중회귀계수 0.965, 검량식의 표준오차 0.086, 포도는 중회귀계수 0.926, 검량식의 표준오차 0.152이었다. 개발된 검량식을 이용하여 예측식을 작성한 결과는 사과의 경우 0.360, 포도 0.210의 결과를 얻었다. 지역간, 년차간 발생되는 변이가 보정된다면 신속한 엽분석 수단이 될 것으로 판단된다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1123-1123
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• 2001

In recent years, a miniature spectrometer has been extensively developed due to the marriage of fiber optics and semiconductor detector array. This type of miniature spectrometer has advantages of low price and robustness due to the capability of mass production and no moving parts are required such as lenses, mirrors and scanning monochromator. These systems are ideal for use in teaching labs, process monitoring and field analyses. A portable near infrared (NIR) system has been developed for qualitative and quantitative analysis. This system includes a tungsten halogen lamp for light source, a fiber optics connected a light source, and a sample module to the microspectrometer, The size of spectrometer can be as small as 2.5 cm x 1.5 cm x 0.1 cm. Wavelength ranges can be chosen as 360-800 nm, 800-1100 nm and 1100-1900 nm depending on the type of detector. The software consists of various tools for multivariate analysis and pattern recognition techniques. To evaluate the system, long and short-term stability, wavelength accuracy, and stray light have been investigated and compared with conventional scanning type NIR spectrometer. This developed system can be sufficiently used for quantitative and qualitative analysis for various samples such as agricultural product, herbal medicine, food, petroleum, and pharmaceuticals, etc.

• 한국광학회지
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• 제28권1호
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• pp.22-27
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• 2017

본 논문에서는 음향광학 파장선택 필터(acousto-optic tunable filter) 기반의 파장훑음 레이저(wavelength swept laser)를 이용한 시간-인코딩 근적외선 분광 기술(time-encoded near-infrared spectroscopy)을 제안하였다. 파장훑음 레이저는 800 nm 근처 영역에서 이득 스펙트럼을 가지는 반도체 광 증폭기(semiconductor optical amplifier)를 기반으로 제작되었으며, 음향광학 파장선택 필터를 공진기 내부에 삽입함으로써 음향광학 파장선택 필터에 인가되는 전기적 라디오주파수에 따라 출력 파장을 선택할 수 있도록 하였다. 본 연구에서는 종래의 기술인 백색광 분광기 기반의 검출부 분광 근적외선 분광 기술과 제안된 파장훑음 레이저 기반의 광원부 분광 근적외선 분광 기술을 각각 이용하여 근적외선 흡수 염료 샘플의 흡광도를 각기 측정하여 실험적으로 비교함으로써 본 연구에서 제안하는 음향광학 파장선택 필터 기반 파장훑음 레이저를 이용한 근적외선 분광 기술의 특성을 증명하였다.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1021-1025
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• 1999

Near-infrared (NIR) spectroscopy has been successfully utilized for the rapid identification of six typical petroleum products such as light straight-run (LSR), naphtha, kerosine, light gas oil (LGO), gasoline, and diesel. The spectral features of each product were reasonably differentiated in the NIR region, and the spectral differences provided enough qualitative spectral information for discrimination. For discrimination, principal component analysis (PCA) combined with Mahalanobis distance was used to identify each petroleum product from NIR spectra. The results showed that each product was accurately identified with an accuracy over 95%. Most noticeably, LSR, kerosine, gasoline, and diesel samples were predicted with identification accuracy of 99%. The overall results ensure that a portable NIR instrument combined with a multivariate qualitative discrimination method can be efficiently utilized for rapid and simple identification of petroleum products. This is especially important when local at-site measurements are necessary, such as accidental petroleum leakage and regulation of illegal product blending.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.3123-3123
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• 2001

Near infrared (NIR) spectroscopy has become a widely used method in food and beverage analysis because of its speed, accuracy and the simplicity of sample preparation. One of the basic requirements of NIR instruments is a wide dynamic range if weak, or small, absorption changes or concentrations are to be measured. Thus the instrument must be sufficiently luminous, and efficient, to enable measurements to be made in a reasonably short time, as for some applications (e.g. sorting) short response times are essential. Diode lasers function the same way as lasers but linewidths are not as narrow as typical lasers. In this work an array of seven laser diodes (in the range of 750-1100 nm) with energy outputs of around hundred milliwatts each were combined with a fast diode array spectrometer (400-1100 nm, 1024 pixels, integration time from 3 ms) as detector. Measurements in transmission mode were performed in solutions of sugars in aqueous solutions and in deuteriumoxide. The feasibility of non-destructive measurements in transmission mode was investigated for different fruits and vegetables.