• Analytical Science and Technology
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• v.10 no.5
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• pp.362-369
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• 1997

Chemometric technique was applied to the sugar composition in five honeys of known botanical or geographical origin following HPLC. Fructose and glucose were predominant carbohydrates in honeys, and small amount of sucrose was also detected in one sample. Sugar contents in honeys samples were compared by the geographical or botanical origin. Fructose/glucose ratio ranged from 0.99 to 1.55 was obtained and these results are in good agreement with the ratio of literature. The plot of principal components analysis(PCA) showed that different honey samples grouped into distinct cluster by the geographical or botanical origin. Increasing the first or second principal component score, higher amount of sugar or less fructose/glucose ratio was observed in PCA plot. Chemometric approach was very useful to provide pattern recognition of sugar profile or quality indices of honey sample and to detect adulteration.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.537-543
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• 2015

In Korea, the use of world geodetic system(WGS) has been mandated in year 2010. Accordingly, the national geographic information institute(NGIS) provides the digital maps according to the WGS. Nevertheless, most of the digital geological maps are still based on the Tokyo Datum(TD). Therefore, users should conduct 2D/3D geological spatial analysis after converting the coordinates of digital geological maps to WGS. The conversion process is often tedious and troublesome for certain users. Therefore, in this study, the method to transform coordinate from TD to WGS using ArcToolbox is introduced for users not familiar with the process. For a better appreciation, the Chungju and Hwanggang-ri digital sheets of 1:50,000 scale was chosen as an example. Here, Chungju and Hwanggang-ri sheets were defined based on the TD-central origin and TD-east origin, respectively. The two sheets were merged after the transformation of TD-east origin of Hwanggang-ri to the TD-central origin, and eventually transformed to WGS-central origin. The merged map was found to match exactly with the digital map(Daeso 367041). The problem of coordinate determination in previous digital geological maps was solved effectively. The proposed method is believed to be helpful to 2D/3D geological spatial analysis of various geological thematic maps.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.125-129
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• 2020

In this study we developed a method for determining the geographic origin of soybeans by combining energy dispersive X-ray fluorescence spectrometry with statistical analysis. In 2018, 197 soybean samples (100 Korean domestic samples and 97 foreign samples) were collected for the construction of a geographic origin model. The mineral concentrations of 26 elements were measured and determined via the fundamental parameters approach. One-way analysis of variance, t-test, and canonical discriminant analysis were employed to reveal five elements (P, Ni, Br, Zn, and Mn) that could be used for the determination of geographic origins. The sensitivity, specificity, and efficiency for the above method were 91.0, 95.9, and 93.4%, respectively. Validation results from 60 samples collected in 2019 showed a predictive rate of 93.3% for Korean domestic soybeans and 100.0% for foreign soybeans. In conclusion, the combination of energy dispersive X-ray fluorescence spectrometry and chemometrics could be used to effectively determine the geographic origin of soybeans.

• Korean Journal of Veterinary Service
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• v.29 no.2
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• pp.111-122
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• 2006

A direct, accurate and sensitive chromatographic analytical method for quantitative determination of four fluoroquinolones (norfloxacin, cirprofloxacin, danofloxacin and enrofloxacin) in chicken, pork and beef edible muscle is proposed in the present study. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. The samples were homogenized and the antimicrobials were added, then they were extracted twice with dichloromethane. Fluoroquinolone antibiotics were separated on an agilent $250x4mm,\;C_{18},\;5{\mu}m$, analytical column, at $25^{\circ}C$. The mobile phase consisted of a mixture of DW : acetonitrile : triethylamine(80:19:1%, v/v, pH 3.0) leading to retention times less than 14 min. at a flow rate 0.5 ml/min. These fluoroquinolones were detected by liquid chromatography with fluorescence at 290 nm excitation and 465 nm emission. The limits of quantification in each edible muscle (chicken, pork, and beef) were 0.32-6.54 ng/g. Using 0.5 g of each sample, average recovery rates at fortification levels of 0.05, 0.1 and 0.2 ${\mu}g/ml$ ranged 70.14-71.71% for NFX, 71.87-73.89% for CFX, 82.16-92.35% for DFX, and 90.13-98.12 for EFX This is a simple and economic method to quantify the presence of NFX, CFX, EFX and DFX in edible muscle of animal origin.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.5
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• pp.19-24
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• 2003

We analysed seismic phases recorded by the 10 December 2002 Cheolwon, Korea, earthquake of $M_{L}$ 3.6 and obtained source parameters such as hypocenter, origin time, earthquake magnitude. Velocity and acceleration records used in this study are from the KMA and KIGAM seismic networks. Due to the location of the epicenter in the north of the DMZ(Demilitarized Zone), direct Pg phases were recorded only at five stations in the area south of DMZ. Identification of refracted Pn phase as the first arrival is difficult in most stations. Therefore, the hypocenter determined by existing routine methods could be affected by a large error. In order to avoid the possibility of the problem, we employed a method of seismic phase analysis developed by Kim et al.. The direct, refracted, and reflected P and S phases were successfully identified using the method together with the travel time curve data. In order to improve the accuracy in determination of the hypocenter and origin time, we included PmP and SmS phases in the analysis in addition to the phases such as Pg, Pn, Sg and Sn. The epicenter, depth, and origin time of the Cheolwon earthquake determined based on data of 11 stations within 200km from the epicenter are $38.81^{\circ}$N, $127.22^{\circ}$E, 12.0km, and 7:42:51.4(local time), respectively. The average value of the local magnitude based on the Richter's definition from all the stations is 3.6 in $M_{L}$. This magnitude is smaller by 0.2 and 0.5 compared with magnitudes determined by KMA and KIGAM, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.149-149
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• 2010

The origin of the inhomogeneous distribution of photoluminescence (PL) peak wavelength on a commercial 2" GaN wafer for green light emitting diode has been investigated by wide momentum transfer (Q) range x-ray diffraction (XRD) profile of InGaN/GaN multiple quantum wells. Near the GaN (0004) Bragg peak, wide-Q range XRD (${\Delta}Q$ > $1.4{\AA}-1$) was measured along the growth direction. Wide-Q XRD gives precise and direct information of ultra-thin InGaN quantum well structure. Based on the QW structural information, the variation of PL spectra can be explained by the combined effect of temperature gradient and slightly uneven flow of atomic sources during the QW growth. In narrow variations of indium composition and thickness of QW, an effective indium composition can be a good character to match structural data to PL spectra.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.58.2-58.2
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• 2020

We present a method for determining the abundance ratio of nitrogen to iron ([N/Fe]) from low-resolution (R~2000) stellar spectra from large spectroscopic surveys such as Sloan Digital Sky Survey (SDSS) and Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The basic idea of the method is to match a grid of synthetic spectra with an observed spectrum in the CN band region around 3883 Å. To calibrate our estimate of [N/Fe], we make use of the giants observed in Apache Point Observatory Galaxy Evolution Experiment (APOGEE), which are also observed in the SDSS. This method will be applied to the Galactic halo stars to determine [N/Fe], and the measured nitrogen abundance ratios will be used to investigate the C-N anti-correlation, which is observed in globular clusters, to trace their origin with their kinematic properties.

• Applied Microscopy
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• v.42 no.3
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• pp.164-173
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• 2012

The relaxor ferroelectric feature in lead-free perovskite oxides, where the dipoles are randomly oriented and they can be feasibly aligned parallel to the external bias, is attracting lots of attention in the field of piezoelectric materials science, since it is one of candidates to replace the toxic lead-based materials that are still being commercially used. However, the origin of relaxor characteristic and its related atomic structure are still ambiguous. In this study, $Na_{1/2}Bi_{1/2}TiO_3$, chosen as a model relaxor system, was found to exhibit a cationic-disordered atomic structure; and furthermore the nonpolar atomic structure and its related oxygen tilting were ascertained via annular bright field imaging skill. We also found that this cationic disordering gives rise to the local formation of atomic vacancies.

• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.229-240
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• 1972

Radioisotopes and their related techniques have recently been applied for scientific conservation works of cultural property and resulted many excellent findings or conservation data which could never be achieved by means of other techniques. Radiocarbon dating have widely been applied for dating the antique of organic origin, whereas the determination of radioactive contents in metal, ceramics, environmental soil, and classical objects could be able to afford many useful informations on the age, genuiness, and archeological significances as it had been produced. Trace quantity of contents of each antique have successfully been analyzed by means of radioactivation analysis or radio active tracer techniques, which could afford important technical data and results for tile conservation of each object. Radiography have also been applied for detecting the internal defects of metal objects and furthermore $\beta$-and ${\gamma}$-ray radiography were proved to be effective for such thin material as textile, painting, and fibres. In this article the detailed principle and procedures of each technique were presented so that the society could be able to make efforts to familiarize all concerns with these modern trends of the conservation techniques of cultural property.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.12 no.2
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• pp.148-160
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• 1999

In order to strengthen objectivity and availability of oriental herb medicine, the standard formula for herbs has been attempted to set up by documentary testing original herbs which were recorded in authorized document. The object herb medicines are CARYOPHYLLI FLOS. After this study, additional experimental verification is required as a matter of fact. As comparison materials, this thesis will be utilized. Specially the internal and external morphological standard in this study is expected to supply the search for several physiochemical reaction, biological reaction, determination of indicator material and identification of gene with basic sources in the future.