• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.267-272
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• 2008

Mid-infrared (MIR) spectroscopy, particularly Fourier transform infrared spectroscopy (FTIR), has emerged as an important analytical tool in quantification as well as identification of multi-atomic inorganic ions such as nitrate. In the present study, the possibility of quantifying soil nitrate via diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) without change of a sample phase or with least treated samples was examined. Four types of soils were spectrally characterized in terms of unique bands of soil contents and interferences with nitrate bands in the range of $2000-1000cm^{-1}$. In order to reduce the effects of soil composition on calibration model for nitrate, spectra transformed to the 1st order derivatives were used in the partial least squared regression (PLSR) model and the classification procedure associated with input soil types was involved in calibration system. PLSR calibration models for each soil type provided better performance results ($R^2$>0.95, RPD>6.0) than the model considering just one type of soil as a standard.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.135-139
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• 2017

We have performed systematic studies of the properties of dust in various environments of nearby galaxies with AKARI. The unique capabilities of AKARI, such as near-infrared (near-IR) spectroscopy combined with all-sky coverage in the mid- and far-IR, enable us to study processing of dust, particularly carbonaceous grains includings polycyclic aromatic hydrocarbons (PAHs), for unbiased samples of nearby galaxies. In this paper, we first review our recent results on individual galaxies, highlighting the uniqueness of AKARI data for studies of nearby galaxies. Then we present results of our systematic studies on nearby starburst and early-type galaxies. From the former study based on the near-IR spectroscopy and mid-IR all-sky survey data, we find that the properties of PAHs change systematically from IR galaxies to ultraluminous IR galaxies, depending on the IR luminosity of a galaxy or galaxy population. From the latter study based on the mid- and far-IR all-sky survey data, we find that there is a global correlation between the amounts of dust and old stars in early-type galaxies, giving an observational constraint on the origin of the dust.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.247-248
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• 2003

Tunable diode laser absorption spectroscopy (TDLAS) has been widely used in environmental monitoring of gaseous species in the past decade. TDLAS is a direct measurement technique for pollutants such as NOx without any interference from other species. Because of its superior spectral purity (～0.001 ­$cm^{-1}$), absorption linewidths with resolvable rotational structure can be studied in the mid infrared region where strong fundamental vibrational transitions of molecules appear. (omitted)

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.279-285
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• 2009

Prediction of glucose concentration in the interstitial fluid (ISF) based on mid-infrared absorption spectroscopy was examined at the glucose fundamental absorption band of 1000 - 1500/cm (10 - 6.67 um) using multi-component analysis. Simulated ISF samples were prepared by including four major ISF components. Sodium lactate had absorption spectra that interfere with those of glucose. The rest NaCl, KCl and $CaCl_2$ did not have any signatures. A preliminary experiment based on Design of Experiment, an optimization method, proved that sodium lactate influenced the prediction accuracy of glucose. For the main experiment, 54 samples were prepared whose glucose and sodium lactate concentration varied independently. A partial least squares regression (PLSR) analysis was used to build calibration models. The prediction accuracy was dependent on spectrum preprocessing methods, and Mean Centering produced the best results. Depending on calibration sample sets whose sodium lactate had different concentration levels, the standard error prediction (SEP) of glucose ranged $17.19{\sim}21.02\;mg/dl$.

• Journal of Sensor Science and Technology
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• v.28 no.4
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• pp.256-261
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• 2019

In this study, mid-infrared transparent zinc sulfide (ZnS) ceramics were fabricated through hydrothermal synthesis with different molar ratios of S/Zn (S/Zn = 0.8, 1.0, 1.2, 1.4, and 1.6). The ZnS ceramics were sintered at a relatively low temperature of $850^{\circ}C$ to prevent the occurrence of the hexagonal phase featuring optical anisotropy. The phase composition, microstructure, and optical properties of the ZnS ceramics were subsequently investigated by employing X-ray diffraction, scanning electron microscopy, and Fouriertransform infrared spectroscopy. The results obtained indicate that the ZnS nanoparticles feature the cubic phase, without the hexagonal phase. Moreover, with increasing S, the crystallinity and particle size of the ZnS nanoparticles increased. The crystallinity and density of the ZnS ceramics improved when the molar ratio of S was higher than the molar ratio of Zn, thereby enhancing the transmittance. Furthermore, the ZnS ceramic with an S/Zn value of 1.2 was found to exhibit the highest transmittance of approximately 69% owing to the reduced occurrence of the hexagonal phase and a high density of 99.8%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.6
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• pp.272-276
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• 2004

Inorganic materials, including gemstones, also have characteristic vibrational energies in the infrared that can be used for identification. For infrared spectroscopy, absorptions associated with the vibrations of the crystal structure (lattice vibrations) are characteristic of the given combination of atoms constituting the gemstone. Natural turquoise $CuAl_6(PO_4)_4\cdot(OH)_8\cdot 5H_2O$ can be distinguished easily from its common substitutes in the infrared range 2000~450$\textrm{cm}^{-1}$ by features in the mid-infrared. Gilson turquoise, which is a synthetic, exhibits a significantly smoother pattern when compared with natural turquoise, because of a different state of aggregation. Also, because the natural turquoise and gibbsite are so different chemically, their patterns are very different. The technique, which is infrared spectroscopy, is nondestructive and, with Fourier transform instrumentation, extremely rapid.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.83-85
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• 2017

We conducted an unbiased near- to mid-infrared imaging and spectroscopic survey of the Large Magellanic Cloud (LMC) as a part of the AKARI Mission Program "Large-area Survey of the LMC" (LSLMC, PI: T. Onaka). An area of about 10 square degrees of the LMC was observed by five photometric bands (3.2, 7, 11, 15, and $24{\mu}m$) and a low-resolution slitless prism ($2-5{\mu}m$, R ~20) equipped with AKARI /IRC. We constructed and publicly released photometric and spectroscopic catalogues of point sources in the LMC based on the survey data. The catalogues provide a large number of near-infrared spectral data, coupled with complementary broadband photometric data. Combined use of the present AKARI LSLMC catalogues with other infrared point source catalogues of the LMC possesses scientific potential that can be applied to various astronomical studies.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1618-1618
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• 2001

Predicting quality traits using near infrared (NIR) spectroscopy on whole grain samples has gained wide acceptance as a non-destructive, rapid and cost effective technique. Barley breeding programs throughout southern Australia currently use this technology as a tool for selecting malting quality lines. For the past 3 years whole grain barley calibrations have been developed at VIDA to predict malting quality traits in the early generation selections of the breeding program. More recently calibrations for whole grain malt have been developed and introduced to aid in selecting malted samples at the mid-generation stage for more complex malting quality traits. Using the same population set, barley and malt calibrations were developed to predict hot water extracts (EBC and IoB), diastatic power, free $\alpha$-amino nitrogen, soluble protein, wort $\beta$-glucan and $\beta$-glucanase. The correlation coefficients between NIR predicted values and laboratory methods for malt were all highly significant ($R^2$ > 0.84), whereas the correlation coefficients for the barley calibrations were lower ($R^2$ > 0.57) but still significant. The magnitude of the error in predicting hot water extract, diastatic power and wort $\beta$-glucan using whole grain malt was reduced by 50% when compared with predicting the same trait using whole grain barley. This can be explained by the complex nature of attempting to develop calibrations on whole grain barley utilizing malt data. During malting, the composition of barley is modified by the action of enzymes throughout the steeping and germination stages and by heating during the kilning stage. Predicting malting quality on whole grain malt is a more reliable alternative to predicting whole grain barley, although there is the added expense of micro-malting the samples. The ability to apply barley and malt calibrations to different generations is an advantage to a barley breeding program that requires thousands of samples to be assessed each year.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.39-46
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• 2014

The green tourmalines from Kayah state, Myanmar were investigated by WD X-ray fluorescence, UV-vis, and mid-infrared spectroscopy for comparison to tourmalines of other deposits. The group of tourmaline was calculated and classified by chemical analysis. The samples belonged to the Calcic group and Uvite. The green tourmalines showed a strong absorption band at 415 and 611 nm. The presence of $V^{3+}$ ions is responsible for these absorption bands. Combination of the stretching and bending mode by the vibration between cationic and hydroxyl units (metal-OH) are observed in the 4600 ~ 4200 $cm^{-1}$.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.3
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• pp.85-92
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• 2015

For concerning the climate change issues, the carbon sequestration and importance of soil organic matter are receiving high attention. To evaluate carbon sequestration in soil is important to determine the soil organic carbon (SOC) fractions such as WESOC (Water extractable soil organic carbon), and $CO_2$ emission by soil microbial respiration. However, the analyses for those contents are time-consuming procedure. There were studied the feasibility of MIRS (Mid-Infrared Spectroscopy), which has short analysis time for determining the WESOC and an incubated carbon in this study. Oven-dried soils at $100^{\circ}C$ and $350^{\circ}C$ were scanned with MIRS and compared with the chemically analyzed WESOC and cumulative carbon dioxide generated during 30, 60, 90, and 120 days of incubation periods, respectively. It was observed that an optimized determination coefficient was 0.6937 between WESOC and untreated soil processed by spectrum vector normalization (SNV) and 0.8933 between cumulative $CO_2$ from 30 days incubation and soil dried at $350^{\circ}C$ after subtracting air-dried soil processed by 1st derivatives. Therefore, it was shown that Quantification of soil organic carbon fractions was possibility to be analyzed by using MIRS.