• Journal of The Korean Astronomical Society
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• v.44 no.4
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• pp.125-134
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• 2011

We present medium resolution (R = 5000 - 6000) spectra in the near-infrared band, 1.4 - 1.8 ${\mu}m$, for template stars in G, K, and M types observed by the echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The identification of lines is based on the spectra of Arcturus (K2 III) in the literature. We measured the equivalent of widths and compared our results to those of Meyer et al. (1998). We conclude that our spectral resolution (R = 6000) data can investigate more accurately the properties of lines in stellar spectra. The library of the template stellar spectra in ASCII format are available for download on the World Wide Web.

• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.165-170
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• 2015

We employed the high-pressure high temperature (HPHT) process to enhance the colors of natural sapphires to obtain a vivid blue. First, we analyze the content of the coloring agent $Fe_2O_3$ using the wavelength dispersive X-ray fluorescence (WD-XRF) method. The HPHT procedure operates under 1 GPa at various temperatures of 1700, 1750, and $1800^{\circ}C$ for 5 minutes using a cubic press. We determine the color changes using the optical microscopic images, UV-VIS near-infrared (NIR) spectra, micro-Raman spectra, and Fourier transform-infrared (FT-IR) spectra for all sapphire samples before and after the treatment. The optical microscopic results indicate that the HPHT process can enhance the sapphire color to a vivid blue at temperatures above $1750^{\circ}C$. The UV-VIS-NIR spectra identify the color changes explicitly and quantitatively through providing the Lab color scales and color differences. Both results demonstrate that the colors of natural sapphires can be enhanced to a vivid blue using the HPHT process above $1750^{\circ}C$ under 1 GPa for 5 minutes.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1276-1276
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• 2001

Polycyclic aromatic hydrocarbons(PAHs) are widely distributed in the environment and are often implicated as potential carcinogens. The chromatographic methods of detection and quantitative determination of PAHs in environmental samples are costly, time consuming, and do not account for all kinds of PAHs. This work describes a quantitative spectroscopic method for the analysis of mixtures of eight PAHs using multivariate calibration models for Fourier transform near infrared(FT-NIR) spectral data. The NIR spectra of mixtures of PAHs (anthracene, pyrene, 1,2-benzanthracene, perylene, chrysene, benzo(a)pyrene, 1-methylanthracene and benzo(ghi)perylene) were measured in the wavelength range from 1100 nm to 2500 nm. The spectral data were processed using a partial least squares regression. We have studied the spectral characteristics of NIR spectra of mixtures of PAHs. It was possible to determine each PAM used in this study at the environmental level(mg L-1) in the laboratory samples. Further development may lead to the rapid determination of more PAHs in typical environmental samples.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1122-1122
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• 2001

A compact and handhold near infrared (NIR) system using microspectrometer was developed. This system was suitable not only in the laboratory, but also in the field or in the process. This system was first applied for classification of geographical origin of herbal medicine such as ginseng and sesame. To identify the origin of ginseng on site, the portable NIR system is more suitable for real field application. For this study, using the compact NIR system, soft independent modeling of class analogies (SIMCA) with 1100-1750 nm NIR spectra was utilized for classification of geographical origin (Korea and China) of both ginseng and sesame. The accuracy of results is more than 90%. Quantitative analysis for petroleum such as toluene, benzene, tri-methyl benzene, and ethyl benzene was performed with partial least squares (PLS) regression with NIR 1100-1750 nm spectra. This study showed that the NIR method and gas chromatography (GC), which is a standard method, have good correlations. Furthermore, the ash content of Cornu Cervi Parvum was analyzed and the accuracy was confirmed by the developed compact NIR system.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1517-1517
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• 2001

Cultural conditions during production of compost, using wheat straw and chicken litter as raw materials, will affect the microbial and biochemical characteristics, leading to a wide variation in mushroom productivity. Over the past 10 years, chemical and instrumental methods, suitable for assessing compost quality have been studied in Northern Ireland. In addition, the use of near subject of investigation over the past 4 years. Previous studies have shown that NIRS can be used fer assessing quality of dried and milled composts. The aim of the current investigation is to develop NIR calibrations for key quality parameters such as dry matter, pH, nitrogen, carbon, ash, microbial population and fibre factions during the two stages of production using spectra of fresh composts. Near infrared reflectance measurements of fresh composts prepared by 6 producers were made during a two-year period. Although the spectra of fresh composts were dominated by two moisture peaks at 1450 nm and 1940 nm, good calibrations for determining moisture content, conductivity, pH, nitrogen, carbon and fibre fractions were developed. The results of quality assessment during commercial production using the calibrations will be presented and discussed.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2002.11a
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• pp.97-117
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• 2002

A chemoinfometrical method for quantitative determination of crystal content of indomethacin (IMC) polymorphs based on fourie-transformed near-infrared (FT-NIR) spectroscopy was established. A direct comparison of the data with the ones collected from using the conventional powder X-ray diffraction method was performed. Pure $\alpha$ and ${\gamma}$ forms of IMC were prepared using published methods. Powder X-ray diffraction profiles and NIR spectra were recorded for six kinds of standard materials with various content of ${\gamma}$ form IMC. The principal component regression (PCR) analyses were performed based on normalized NIR spectra sets of standard samples of known content of IMC ${\gamma}$ form. A calibration equation was determined to minimize the root mean square error of the prediction. The predicted ${\gamma}$ form content values were reproducible and had a relatively small standard deviation. The values of ${\gamma}$ form content predicted by two methods were in close agreement. The results were indicated that NIR spectroscopy provides for an accurate quantitative analysis of crystallinity in polymorphs compared with the results obtained by conventional powder X-ray diffractometry.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.127-127
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• 2010

Owing to many advantages on indirect intersubband absorption from the hole miniband to the electron miniband based on the type-II band alignment in InAs/GaSb strained-layer superlattice (SLS), InAs/GaSb SLS infrared photodetector (SLIP) has emerged as a promising system to realize high-detectivity quantum photodetector operating up to room temperature in the spectral range of mid-infrared (MIR) to far-infrared (FIR). In particular, n-barrier-n (n-B-n) structure designed for blocking the majority-carrier dark current makes it possible for MIR/FIR dual-band SLIP whose photoresponse (PR) band can be exclusively selected by the bias polarity. In this study, we present the MIR and FIR photoresponse (PR) mechanism identified by dual-band PR spectra and photoluminescence (PL) profiles taken from InAs/GaSb SLIP. In the MIR/FIR PR spectra measured by changing bias polarity, each spectrum individually shows a series of distinctive peaks related to the transitions from the hole subbands to the conduction one. The PR mechanism at each polarity is discussed in terms of diffusion current, and a superposition of MIR-PR in the FIR-PR spectrum is explained by tunnelling of electrons activated in MIR-SLS. The effective FIR-PR spectrum decomposed into three curves for HH1, LH1, and HH2 has revealed the edge energies of 120, 170, and 220 meV, respectively, and the temperature variation of the MIR-PR edge energies shows that the temperature behavior of the SLS systems can be approximately expressed by the Varshni empirical equation.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.151.2-151.2
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• 2011

IGRINS (Immersion GRating INfrared Spectrometer) will provide the spectra with high-resolution and an instantaneous spectral coverage of H and K band in NIR region. Therefore, it is expected that the wide coverage of wavelength would make a production of an extensive NIR high-resolution spectra of standard stars as a prior program of IGRINS. As a counter part of these NIR spectra, we have planned to obtain the high-resolution spectra of those standard stars in optical band. These optical high-resolution spectra would give us an opportunity to produce the library of high-resolution stellar spectra covering from optical to NIR band, and to confirm the method to determine the stellar parameters and chemical abundances from the NIR high-resolution spectra. Before using the NIR high-resolution spectra, we have tested the method to determine the stellar parameters by comparing between the observed spectra and the synthetic spectra in optical band. In order to make the synthetic spectra, we have used the Kurucz ATLAS9 model grids and the SYNTH code described by Fiorella Castelli (http://wwwuser.oat.ts.astro.it/castelli/). For the cross-check against the parameters that would be derived from the NIR spectra, the stellar parameters such as effective temperature and surface gravity were determined using the optical spectra of the solar-like stars, as preliminary results.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.39-51
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• 1989

The infrared and resonance Raman spectra are reported for nickel and zinc tetraphenylchlorins. It is found that the IR and RR spectra become more complicated compared with the corresponding porphyrin analogs due to the symmetry changes. Some vibrational parameters like the core size and the symmetry change are examined in accordance with vibrational spectra of other type of chlorins.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.157-161
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• 2017

The dusty torus of Active Galactic Nuclei (AGNs) is one of the important components for the unification theory of AGNs. The geometry and properties of the dusty torus are key factors in understanding the nature of AGNs as well as the formation and evolution of AGNs. However, they are still under discussion. Infrared observation is useful for understanding the dusty torus as thermal emission from hot dust with the dust sublimation temperature (~ 1500 K) has been observed in the infrared. We have analyzed infrared spectroscopic data of low-redshift and high-redshift quasars, which are luminous AGNs. For the low-redshift quasars, we constructed the spectral energy distributions (SEDs) with AKARI near-infrared and Spitzer mid-infrared spectra and decomposed the SEDs into a power-law component from the nuclei, silicate features, and blackbody components with different temperatures from the dusty torus. From the decomposition, the temperature of the innermost dusty torus shows the range between 900-2000 K. For the high-redshift quasars, AKARI traced rest-frame optical and near-infrared spectra of AGNs. Combining with WISE data, we have found that the temperature of the innermost dusty torus in high redshift quasars is lower than that in typical quasars. The hydrogen $H{\alpha}$ emission line from the braod emission line region in the quasars also shows narrow full width at half maximum of $3000-4000km\;s^{-1}$. These results indicate that the dusty torus and the broad emission line region are more extended than those of typical quasars.