• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.795-800
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• 1998

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.2
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• pp.82-87
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• 1989

A field experiment was carried out to determine the effects of 11 different application levels of nitrogen (N), phosphorous ($P_2O_5$) and potassium($K_2O$) fertilizer in late-autumn on the winter survival, early spring growth and dry matter(DM) yield, carbohydrate reserves (CHO-R) in stubble of grasses, and botanical composition in orchardgrass dominated existing pasture in Suwon from October, 1987 to May, 1988. Winter survival of grasses was high (ca. 90%) in all N-fertilized plots, regardless of $P_2O_5$ and $K_2O$ application, and those in zero-N and zero-NPK plots were low as 86.5% and 81.4%, respectively. Early spring growth was vigorous in N-fertilized plots. Heading rate at the fist harvest was 80-86% in all N plots, regardless of $P_2O_5$ and $K_2O$, while those in zero-N and zero-NPK plots were very low as 61% and 56%, respectively. The DM yield of first harvest was higher in the plots of N 35 kg(Site B) and N 70kg $ha^{-1}$ (Site A), regardless of $P_2O_5$ and $K_2O$ level, and those in zero-N and zero-NPK plots were very low (p < 0.05). But no significant difference of yield was observed between N 75 kg and N 105 kg. CHO-R in stubble and legumes were high in zero-N and zero-NPK plots, and low relationship was found between winter survival and CHO-R of grasses. Winter survival, early spring growth and DM yield were significantly influenced by N fertilizer. In this experiment, the optimum application level of N in late-autumn could be recommended in 35-70 kg $ha^{-1}$, and no beneficial effects were observed by $P_2O_5$ and $K_2O$ fertilizer.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.51.1-51.1
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• 2010

We present the interim results of simultaneous observations of SiO and H2O masers toward 401 known stellar SiO and/or H2O maser sources (166 both SiO and H2O maser sources, 83 only SiO maser sources, and 152 only H2O maser sources) using KVN_Yonsei telescope. The results of 166 known SiO/H2O maser sources will be presented by Kim et al. and the results of 83 only SiO maser sources and 152 only H2O maser sources presented here. Both SiO and H2O maser emission were detected from 30 sources giving a detection rate of 36 % toward known 83 only SiO maser sources, while they were detected from 66 sources giving a detection rate of 43 % toward known 152 only H2O maser sources at one epoch observation. Only SiO masers were detected from 42 sources toward 83 only SiO sources, while they were detected from 28 sources toward 152 only H2O sources. Characteristics of these observed sources in the IRAS two-color diagram is investigated including mutual relations between SiO and H2O maser emission. In addition, these results will be useful for statistical study of late-type stars and future VLBI observations.

• Korean Journal of Metals and Materials
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• v.47 no.3
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• pp.188-194
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• 2009

Recently, new extraction technology for manganese nodule has been developed as alternative noble metallic resources. It is important to understand thermodynamic behaviors of phosphorus in low basic slag system from the viewpoint of the refining processing optimization. Thermodynamic behaviors of phosphorus in the $FeO-MnO-CaO-SiO_2-MgO_{satd.}$ slag system were investigated at 1723 K with various oxygen potential and slag composition of low basicity. The experimental results for dependence of phosphorus on oxygen potential and slag basicity indicated that the dissolution mechanism of phosphorus into slag of low basicity could be derived as follows; $[P]+5/4O_2+(O^{2-})=({PO_{3.5}}^{2-})$ Present experimental results implied that stability of phosphorus in slag would be depended on both of $O^{2-}$ (basicity) and content of $Ca^{2+}$ in molten slag. The thermodynamic effect of FeO, MnO and $Na_2O$ on low basicity on phosphate capacity was discussed.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.229-235
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• 2006

High speed PC-based DIO(Digital I/O) system that consists of a master device and slave I/O devices is developed. The PCI interfaced master device controls all of serial communications, reducing the load on the CPU to a minimum. The slave device is connected from the master device and another slave device is connected to the slave device, it can repeated to maximum 64 slave devices. The slave device has 3 types I/O mode, such as 16 bits input-only, 16 bits output-only, and 8bits input-output. The master device has 2 rings which can take 64 slaves each. Therefore, total I/O points covered by the master is 2048 points. The slave features 3 types of input/output function interchangeability by DIP switch settings. Library, application, and device driver software for the DIO system that have a secure and a convenient functionality are developed.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3239-3243
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• 2014

We have developed a simple method for tuning the morphologies of $Cu_2O$ microcrystals. $Cu_2O$ microcrystals were prepared by precipitation at room temperature from a mixture of $Cu(CH_3COO)_2{\cdot}H_2O$, N,N,N',N'-tetramethyl ethylenediamine (TMEDA), ascorbic acid, and polyethylene glycol (PEG). TMEDA was used to promote the formation of copper-TMEDA complexes. A variety of $Cu_2O$ microcrystal morphologies were obtained simply by varying the concentrations of TMEDA and ascorbic acid. Aggregated $Cu_2O$ microspheres are formed at higher concentrations of ascorbic acid in the absence of TMEDA. Aggregated $Cu_2O$ microcubes are formed at lower concentrations of ascorbic acid and higher concentrations of TMEDA. The crystal growth mechanism of these $Cu_2O$ morphologies is explained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.344-344
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• 2010

A capacitor with engineered tunnel barrier composed of High-k materials has been fabricated. Variable oxide thickness (VARIOT) barrier consisting of thin SiO2/HfO2/Al2O3 (2/1/3 nm) dielectric layers were used as engineered tunneling barrier. We studied the electrical characteristics of multi stacked tunnel layers for various RTA (Rapid Thermal Anneal) and FGA (Forming Gas Anneal) temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1566-1571
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• 2009

The discharge electrodes in ac PDP are coated with dielectric layer, and transparent MgO thin films are deposited on the dielectric layer. The main role of the MgO thin films in ac PDP is to protect the dielectric layer from sputtering by ion bombardment in the glow-discharge plasma. An additional important role of the MgO thin film is the high secondary electron emission coefficient which leads the low firing voltage and low cost of the PDP. In this paper, we investigated the relations of the crystal orientation about deposition thickness, deposition rate, temperature of substrate, and distance between the MgO tablet and the substrate. Additionally, we investigated the discharge characteristics of the AC PDP using nano-powder MgO tablet

• Journal of environmental and Sanitary engineering
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• v.19 no.2
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• pp.1-6
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• 2004

In Bok-Jeong water treatment plant, chlorination is the only technique used for disinfection of drinking water. This disinfecting treatment leads to the formation of trihalomethanes (THMs). This study was carried out to investigate the possibility of improving removal efficiency of THM precursor in the conventional water treatment processes by $TiO_2$ photocatalytic oxidation. Removal efficiencies of DOC, $UV_{254}$, THMFP were low in the conventional water treatment processes. With application of $TiO_2$ photocatalyst, DOC, $UV_{254}$, THMFP were reduced more effectively. As the $TiO_2$ photocatalytic reaction time increased, the removal efficiencies of DOC, $UV_{254}$, THMFP were increased. The $TiO_2$ photocatalytic removal efficiencies of DOC, $UV_{254}$, THMFP were increased with increasing $TiO_2$ dosage. However, over 0.6g/l of $TiO_2$ dosage, the efficiency reached a plateau.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.31-33
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• 1992

This paper is studies the addition effects of $La_2O_3$ on the magnetic properties of Sr ferrite. Compositions were chosen according to the formula $[SrO{\cdot}nFe_2O_3]_{100-x}(La_2O_3)_x$. where n was varied between 5.8~6.1 and x between 0~3. The composition of the best value $(BH)_{max}$=1.48MGOe was n=6(stoichiometric composition) and x=2 at $La_2O_3$ addition. This value was higher than that of ordinary isotropic strontium ferrite.