• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.223-239
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• 2005

The vascular plants collected from Dongwol Valley in Mt. Gyeryongsan, national park were composed of all 248 taxa including cultivated species, and classified into 1 phylum, 4 classes, 3 subclasses, 34 orders, 84 families, 178 species, 33 varieties and 4 forms. As compared the flora of the commonly distributing species of this region with those of the southern part, the middle part, the northern part of the Korean Peninsula, Jeju-do Island and Ulreung-do Island, the proportion of them were $90.3\%,\;98.0\%,\;79.0\%,\;73.8\%$ and $62.1\%$, respectively. One taxon of the plants distributed only in the southern part, 3 taxa of those in the middle part, 5 taxa of those in the middle-northern part and 23 taxa of those in the middle-southern part were found in this Valley. Natural resource plants were categorized into edible 118 taxa, medicinal 78 taxa, industrial 46 taxa, ornamental 39 taxa, timber 14 taxa and fiber 9 taxa. Four taxa of the Korean endemic plants are distributed in Dongwol Valley. The vegetation of the valley is Quercus and Rhododendron mixed forest, and it belongs to the boundary between the middle part and the southern part in the floral zone of the Korean Peninsula.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.1
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• pp.23-28
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• 2010

The cylindrical magnetron sputtering has not been widely used, although this system is useful for only certain types of applications such as fiber coatings. This paper presents electrode configurations which improved the complicacy of the target assembly by using the positive voltage power supply. It is a modified type which has a target constructed with a large cylindrical part, a conical part and a small cylindrical part. When positive voltage was applied to an anode, a stable glow discharge was established and a high deposition rate was obtained. The substrate bias current was monitored to estimate the effect of ion bombardment. As a result, it was found that the substrate current was large. With cylindrical and conical cathode magnetron sputter deposition on the surface of the substrate to prevent re-sputtering, ion impact because it can increase the effectiveness with excellent ductility and adhesion of Ti film deposition can be obtained. We board at the front end of the ground resistance of $5\;k{\Omega}$ attached to the substrate potential can be controlled easily, and Ti film deposition with excellent adhesion can be obtained. Microstructure and morphology of Ti films deposited on pure Cu wires were investigated by scanning electron microscopy in relation to preparation conditions. High level ion bombardment was found to be effective in obtaining a good adhesion for Cu wire coatings.

• 보존과학연구
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• s.13
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• pp.81-95
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• 1992

The old books which have been colored to brown spots were analyzed chemically to compare with white part. The original raw materials were paper mulberry (Broussonetia Kazine) and woodpulp. White part contained58.8%($\alpha$-37.2%,$\beta$-8.6%, $\gamma$-12.7%)cellulose, 21.7% hemicellulose, 19.8% lignin,4.4% pentosan and brown sopt part contained 49.1%($\alpha$-19.8%, $\beta$-14.5%,$\gamma$-14.8%) cellulose, 27.1% hemicellulose, 23.8% lignin, 4.8% pentosan. Both of brown spot and white parts contained starch without protein. The pH was 4.9 in brown and 5.0 in white part respecitively. The brown spot parts were more solidified than white parts according to SEM observation. Difference of organiccompinent in brown part came from white part were 2-hydroxy-benzaldehydeand phenol.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1046-1054
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• 2001

Bioleaching is the process in which insoluble metal sulfide is oxidized by specialized iron- and/or sulfur-oxidizing lithotrophic bacteria in acidic, metal-rich environments. Most of these processes are carried out by the genus Thiobacillus. Three novel Thiobacillus strains (Thiobacillus thiooxidans AZ11, Thiobacillus thiooxidans MET, and thiobacillus thiooxidans TAS) associated with bioleaching have been isolated from soil and sludge (Korean patent No. 1999-0073060 for T. thiooxidans AZ11, Korean patent No. 1999-0005798 for T. thiooxidans MET, and Korean patent No. 1999-0073059 for T. thiooxidans TAS). A partial sequence of 16S ribosomal RNA gene (16S rDNA) and the entire sequence of 16S/23S intergenic spacer region (ISR) were determined in the three above novel strains and in Thiobacillus ferrooxidans ATCC19859 as a reference strain. When phylogenetic analysis was performed based on G+C contents and sequence alignments, T. ferroxidans ATCC19859 was found to be closely related to previously registered T. ferrooxidans strains in a monophyletic manner, while the three novel T. thiooxidans strains were classified in a paraphyletic manner. Close examination on the base composition of 16S/23S ISR revealed that the 5\` part (nucleotide residues 21-200) was specific for the genus Thiobacillus. On the other end, the 3\` part (nucleotide residues 201-520) showed specificity in T. ferrooxidans strains, but not in T. thiooxidans strains. These results suggest that the proximal and distal halves of 16S/23S could be used as a genetic marker for the identification of the genus Thiobacillus and the species T. ferrooxidans, respectively.

• Research in Mathematical Education
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• v.23 no.3
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• pp.165-179
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• 2020

In this article, the author's intent is to begin a conversation centered on the question: How was the integration of digital technology into elementary mathematics classrooms framed? In the first part of the discussion, the author provides a historical perspective of the development of theoretical perspectives of the integration of digital technology in learning mathematics. Then, the author describes three theoretical perspectives of the role of digital technology in mathematics education: microworlds, instrumental genesis, and semiotic mediation. Last, based on three different theoretical perspectives, the author concludes the article by asking the reader to think differently.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.669-681
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• 2010

Value-at-Risk(VaR) is an important part of risk management in the financial industry. This paper present a VaR forecasting for financial time series based on the quantile regression for GARCH models recently developed by Lee and Noh (2009). The proposed VaR forecasting features the direct conditional quantile estimation for GARCH models that is well connected with the model parameters. Empirical performance is measured by several backtesting procedures, and is reported in comparison with existing methods using sample quantiles.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.369-373
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• 2002

The liquid phase oxidation of p-xylene has been carried out with oxygen-enriched gas, and the manganese component was precipitated probably via over-oxidation to $Mn^{4+}$. The precipitation increased with rising oxygen concentration in the reaction gas and occurred mainly in the later part of the oxidation. The activity of the reaction decreased, and the blackening of the product and side reactions to carbon dioxide increased with the degree of precipitation. Precipitation can be decreased with the addition of metal ions, such as cerium, chromium and iron.

• Korean Journal of Mathematics
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• v.23 no.2
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• pp.259-267
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• 2015

This paper is devoted to investigate the existence of the solutions for a class of the noncooperative elliptic system involving critical Sobolev exponents. We show the existence of the negative solution for the problem. We show the existence of the unique negative solution for the system of the linear part of the problem under some conditions, which is also the negative solution of the nonlinear problem. We also consider the eigenvalue problem of the matrix.

• Journal of Environmental Science International
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• v.23 no.3
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• pp.399-407
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• 2014

In this study, before and after sunset carbon dioxide concentration and air temperature were observed in two points of atmosphere (lower observation point of the GL + 0.1 m, the upper observation point of GL + 1.0 m) on the foreshore at located in Suncheon Bay and their variations were analyzed. Observation was performed on the foreshore on 2~4 August 2010. Instrument (VAISALA, GMP343) was set two hours before sunset and then observation was made continuously for six hours. In three days, observed carbon dioxide concentration was 375~419 ppm, and the air temperature was in the range of $28.7{\sim}32.5^{\circ}C$. The average concentration of carbon dioxide was 388~399 ppm in the upper observation point and 386~396 ppm in the lower observation point. It was higher in the upper observation point and its fluctuations were similar in two observation points. Correlation coefficients between carbon dioxide concentration and air temperature in the upper observation point were in the range of -0.64~-0.88, and were calculated -0.65 to -0.90 in the lower observation point. For the carbon dioxide concentration, correlation coefficients between the upper part and the lower part were very high as 0.98 in three times. For the air temperature, correlation coefficients between the upper part and the lower part were very high as 0.97 and 0.99. In the same observation time, the slope of the linear regression function as carbon dioxide concentration in the lower observation point for the upper observation point was in the range of 0.97~1.01. Carbon dioxide concentration was slightly higher in the upper observation point. Because carbon dioxide in the lower observation point was closer on the surface of the foreshore and absorbed from atmosphere to the foreshore. In this study, it was showed that the vertical variation of carbon dioxide concentration was insignificant in the several meter scale of atmosphere on the surface of the foreshore.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5953-5956
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• 2013

Background: Cholangiocarcinoma (CCA) is the most common cancer in Northeast Thailand. It is also a crucial health problem for Thai people. Various risk factors for CCA have been identified in the upper part of Northeast Thailand, but no similar studies of risk factors have been conducted in the lower parts of the region. This study aimed to investigate factors associated with CCA in the resident population. Materials and Methods: A hospital-based case-control study was conducted during 2009-2012 with the recruitment of 123 CCA cases and 123 non-CCA patient controls, matched for sex, age and residential area. Information was collected by interview with a structured questionnaire. Blood samples were collected for assays of anti-OV antibodies. Associations between various personal factors, dietary habits, family history, the presence of anti-OV antibodies and CCA were analyzed using multiple conditional logistic regression. Results: Patients who consumed raw meat (beef, pork) and alcoholic beverages ${\geq}3$ times per week had a higher risk of CCA than non-consumers ($OR_{adj}$=4.33; 95%CI=1.14-16.35 and $OR_{adj}$=2.13; 95%CI=1.00-4.55, respectively). Patients who had a family history of cancer had a higher risk than those who did not ($OR_{adj}$=4.34; 95%CI=1.80-10.43). Also, patients who had anti-OV antibodies (AU>23.337) had a higher risk than those whose anti-OV antibodies were below the cut-off ($AU{\leq}23.34$) ($OR_{adj}$=3.09; 95%CI=1.04-9.16). Conclusions: As is the case in the upper part of Northeast Thailand, OV infection is a crucial risk factor for CCA in people who live in lower part of the region. Similarly, a family history of cancer and the consumption of alcohol are risk factors for CCA.