• Journal of the Korean Ceramic Society
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• v.30 no.11
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• pp.897-904
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• 1993

CdS doped SiO2 glass coating films which are good candidates for the nonlinear optical materials were prepared by the Sol-Gel method. TEOS, C2H5OH, H2O and HCl were used as starting materials to obtain SiO2 matrix solutions. Then Cd(NO3)2.2H2O and CS(NH2)2 were dissolved into the SiO2 matrix solutions. Coating was performed several times in order to increase the thickness of coated film by the dip-coating method. Then heat treatments were carried out to control the size of CdS microcrystals doped in SiO2 glass matrix with respect to temperatures and times. CdS-doped SiO2 transparent coating films were successfully obtained. CdS crystals were changed from cubic to hexagonal type about $600^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.386-390
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• 1990

Yttrium oxysulfide incoporated with europium has been prepared by direct heating the mixture of $Y_2O_3,\;Eu_2O_3,\;NaOH(or\;Na_2CO_3)$, and S. The reaction of the mixture at low temperatures and treatment at higher temperatures are studied. The formation of $Y_2O_2S$ is completed at lower temperature (ca. 500$^{\circ}C$) and incorporation of $Eu^{3+}$ into $Y_2O_2S$ lattice proceeds at higher temperature (above 1000$^{\circ}C$) along with crystal growth. Small amount of the unknown phase considered to be $Y_2O_2S_2$ is formed along with $Y_2O_2S$ in the temperature range from 400$^{\circ}C$ to 460$^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.2
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• pp.85-90
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• 2013

This study was conducted to examine the basis for the information to select the suitable potato varieties grown in new reclaimed land. The potatoes of five varieties were planted in the port with 4 different electrical conductivities of saturated extracts of soil taken the Saemangeum reclamation area, which was made of non-treatment salt and three concentrations of salt treatment, 1.6 dS $m^{-1}$, 3.2 dS $m^{-1}$, 4.8 dS $m^{-1}$, respectively. All of the potato varieties were uniformly emerged without missing plant in all treatment groups, even 4.8 dS $m^{-1}$ treatment group. According to the salt concentration of soil, required date to the emergence of the potato comparing to non-treatment salt was delayed 3-4 days in 1.6 dS $m^{-1}$, 6-10 days in 3.2 dS $m^{-1}$, 7-13 days in 4.8 dS $m^{-1}$, respectively, and the number of its branch decreased by 14-58% comparing to non-treatment salt depending on varieties. Since the increase of the salt concentration of the soil was more serious the decrease of the number of its branch, but plant height tended to increase when branch number per plant was small, which was depending on more number of its branch than salt concentration. Fresh tuber yield of potato comparing to non-treatment salt were decrease 33.7% in 1.6 dS $m^{-1}$, 59.5% in 3.2 dS $m^{-1}$, 79.3% 7-13 days in 4.8 dS $m^{-1}$, respectively. The threshold EC starting the growth inhibition of fresh weight decreased was 1.2 dS $m^{-1}$ for Chudong, 1.8 $m^{-1}$ for Chubeak, 1.9 $m^{-1}$ for Chugang and Chuyeong, and 2.0 $m^{-1}$ for Sumi, and EC which decreased 50% of dry weight index was 2.4 dS $m^{-1}$ for Chubaek, 2.45 dS $m^{-1}$ for Chudong, 2.81 dS $m^{-1}$ for Chugang, 3.03 dS $m^{-1}$ for Chuyeong, and 3.29 dS $m^{-1}$ for Sumi. The present results suggest that Sumi is considered to the suitable potato variety grown on saline soils.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.315-323
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• 1991

The preparation of zirconium carbide powders by the halogenide process of ZrCl4-C-Mg system (1:1:2, molar ratio) was studied between 300。 and 120$0^{\circ}C$ under Ar gas flow (200 mι/min). The formation mechanism and kinetics of zirconium carbide and characteristics of the synthesized powder were examined by TG-DTA, XRD, SEM and PSA. 1) The formation mechanism of zirconium carbide were as follows, above 30$0^{\circ}C$ ZrCl4(S)+Mg(s)longrightarrowZrCl2(s)+MgCl2(s) above 40$0^{\circ}C$ ZrCl2(S)+Mg(s)longrightarrowZr(s)+MgCl2(s) above 50$0^{\circ}C$ Zr(s)+C(s)longrightarrowZrC(s) 2) The apparent activation energy of the reduction-carbonization at temperature of 800$^{\circ}$to 100$0^{\circ}C$ was 11.9 kcal/mol. 3) The lattice parameter and the crystallite size of ZrC which was produced from the mixture powder of ZrCl4, C and Mg (1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were 4.700A and 180A, respectively. 4) The powders obtained from the mixture powder of ZrCl4, C and Mg(1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were agglomerate with the average size of about 13${\mu}{\textrm}{m}$ in SEM micrograph.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.1-8
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• 2019

Developing reliable soil moisture prediction techniques at agricultural regions is a pivotal issue for sustaining stable crop productions. In this study, a physically-based SWAP(Soil-Water-Atmosphere-Plant) model was suggested to estimate soil moisture dynamics at the study sites. ROSETTA was also integrated to derive the soil hydraulic properties(${\alpha}$, n, ${\Theta}_r$, ${\Theta}_s$, $K_s$) as the input variables to SWAP based on the soil information(Sand, Silt and Clay-SSC, %). In order to predict the soil moisture dynamics in future, the mid-term TIGGIE(THORPEX Interactive Grand Global Ensemble) and long-term S2S(Subseasonal to Seasonal) weather forecasts were used, respectively. Our proposed approach was tested at the six study sites of RDA(Rural Development Administration). The estimated soil moisture values based on the SWAP model matched the measured data with the statistics of Root Mean Square Error(RMSE: 0.034~0.069) and Temporal Correlation Coefficient(TCC: 0.735~0.869) for validation. When we predicted the mid-/long-term soil moisture values using the TIGGE(0~15 days)/S2S(16~46 days) weather forecasts, the soil moisture estimates showed less variations during the TIGGE period while uncertainties were increased for the S2S period. Although uncertainties were relatively increased based on the increased leading time of S2S compared to those of TIGGE, these results supported the potential use of TIGGE/S2S forecasts in evaluating agricultural drought. Our proposed approach can be useful for efficient water resources management plans in hydrology, agriculture, etc.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.243-247
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• 2003

To examine ideal leaf types with higher $\textrm{CO}_2$ assimilates and different seed sizes, 12 soybean varieties were planted on the pot in a plastic house covered with glass. Leaf function based on stomatal conductance and $\textrm{CO}_2$ assimilation in soybean is different in seed size and leaflet shape. Mean $\textrm{CO}_2$ assimilation of a single leaf was 19.66 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$ and showed higher in small seed cultivars with narrow leaflet than that of small seeds with wide leaflet (18.29 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$), but within large seed groups, it was higher in wide leaflets (19.17 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$) than narrow leaflet cultivars (17.45 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$). In small seed and narrow leaflet cultivars, stomatal conductance ranged from 0.14 to 0.15 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$, while $\textrm{CO}_2$ assimilation ranged from 19 to 20 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$. The Photosynthetic rate was closely related to stomatal conductance, transpiration and water use efficiency.

• Journal of the Korean Vacuum Society
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• v.13 no.2
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• pp.92-98
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• 2004

DBPAS has been used to characterize atomic size defect structures in materials. In this investigation the numerical analysis of the Doppler spectra was employed to the determination of the shape parameter, S, defined as the ratio between the amount of counts in a central portion of the spectrum and the total counts of whole spectrum. As the samples were exposed by X-ray increasing the exposed doses from 3, 6, and 9 Gy with 6 MV and 15 MV, respectively and also irradiated by X-ray as the medical applications used for in 0, 2, 4 and 6 years. The S-parameter values were increased as increasing the exposed time and the energies, that indicated the defects generate more. The S-parameters of the samples with medical treatment is varied from 0.4932 to 0.4956.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.383-388
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• 1986

Kinetics of the reaction of 2-phenylethylarenesulfonates with pyridine in acetonitrile were investigated by an electric conductivity method under 1 to 2,000 bars and at 40∼60${\circ}C$. The rates of these reactions were increased with raising temperatures and pressures, but less than those of the reactions of benzyl benzenesulfonate with pyridine in acetoneitrile were investigated by an electric conductivity method under 1 to 2,000 bars and at 40~60${\circ}C$ .The rates of these reactions were increased with raising temperatures and pressures, but less than those of the reaction of benzyl benzenesulfonate with pyridine in acetone. The activation volumes and activation entropies of 2-phenylethyl m-nosylate were more negatively large than those of benzyl benzenesulfonate. From these phenomena it can be deduced that 2-phenylethyl system has more firmly $S_N2$ character in tranistion state. The Hammett reaction constants are also estimated from the second-order reaction constants. With increasing pressures the reaction parameters $({\rho})$ were decreased, but the $S_N2$ characters were increased. From these results, the reaction mechanism can be adequately described as typical $S_N2$ process under high pressure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.10a
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• pp.93-99
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• 1997

High Temperature wear behavior of plasma sprayed ZrO$_2$ and MoS$_2$, $Fe_2O_3$ coatings were investigated for high temperature wear resistance applications. The MoS$_2$, $Fe_2O_3$ added powders containing 2.5, 5.0, 7.5, 10.0 mol% of $MoS_2$, $Fe_2O_3$ for plasma spray were made by spray drying method. Wear test were performed at temperature ranges from room temperature to 600$\circ$C. The microstructural change of coatings and the worn. surface were examined by SEM and XRD. In ZrO$_2$ coating, the coefficient of friction and wear amount of room temperature to 400$\circ$C was increased with temperature and decreased with temperature over 400$\circ$C. The coefficient of friction and wear amount of MoS$_2$ added coatings were increased with temperature, but those of $Fe_2O_3$ added coatings had lower coefficient of friction and higher wear resistance than ZrO$_2$ coating.

• Tuberculosis and Respiratory Diseases
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• v.53 no.3
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• pp.294-308
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• 2002

Background : The cell-mediated immune response plays an important role in tuberculosis. After being activated by mycobacterial antigens, T lymphocytes express a high affinity receptor (IL-2R) for interleukin-2 (IL-2) on their own surface and release a soluble fraction of the IL-2 receptor (sIL-2R) from the cell membrane into the circulation. Neopterin is a metabolite of guanosine-triphosphate, which is produced by stimulated macrophages under the influence of IFN-$\gamma$ with a T lymphocyte origin. Therefore, the utility of sIL-2R, IFN-$\gamma$ and the neopterin levels as immunologic indices of the cell-mediated immune response and severity of disease in patients with pulmonary tuberculosis was assessed. Methods : The serum sIL-2R, IFN-$\gamma$ and neopterin levels were measured in 39 patients with pulmonary tuberculosis, 6 patients with tuberculous lymphadenitis prior to treatment and 10 healthy subjects. The serum and pleural sIL-2R, neopterin and ADA levels were measured in 22 patients with tuberculous pleurisy. The patients with pulmonary tuberculosis were divided into a mild, moderate and severe group according to the severity by ATS guidelines. To compare the results from these patients with those of the pretreatment levels, the sIL-2R, IFN-$\gamma$ and neopterin levels were measured in 36 of the 39 patients(1 patient, expired; 2 patients were referred to a sanitarium) with pulmonary tuberculosis after 2 months of treatment. Results : 1) the serum sIL-2R and IFN-$\gamma$ levels were elevated in patients with tuberculosis when compared to those of healthy subjects (p>0.05). The neopterin concentration in the serum was significantly lower in patients with pulmonary tuberculosis($2967{\pm}2132.8$ pg/ml) than in healthy controls($4949{\pm}1242.1$ pg/ml)(p<0.05). 2) In the pulmonary tuberculosis group, the serum sIL-2R and IFN-$\gamma$ levels were higher in patients with severe disease than those in patients with mild and moderate disease. However, the neopterin levels declined as the pulmonary tuberculosis became more severe (p<0.01). 3) The mean serum sIL-2R and IFN-$\gamma$ levels declined from $1071{\pm}1139.4$ U/ml to $1023{\pm}1920.9$ U/ml(p>0.05), $41{\pm}52.8$ pg/ml to $22{\pm}23.9$ gm/ml(p<0.05), respectively, after 2 month of treatment. The mean serum neopterin levels increased from $3158{\pm}2272.6$ pg/ml to $3737{\pm}2307.5$ pg/ml(p>0.05) after a 2 month of treatment. These findings were remarkable in the severe group of pulmonary tuberculosis with a clinical correlation. 4) In the patients with tuberculous pleurisy, the serum sIL-2R and ADA were significantly higher than those in the pleural fluid, However, the neopterin levels in the sera and pleural effusion were similar. Conclusion : On the basis of this study, sIL-2R, IFN-$\gamma$ and neopterin measurements may not only provide an insight into the present state of the cell-mediated immune response, but also serve as parameters monitoring of the prognosis of the disease, particularly in patients with severe pulmonary tuberculosis. In addition, an assay of the pleural sIL-2R levels might signal a stimulated local immunity including T cell activation in the tuberculous pleural effusion.