• Proceedings of the Korea Association of Crystal Growth Conference
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• 2000.06a
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• pp.1-33
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• 2000

Silicon carbide ceramics with sintering additives from the system AlN-Y$_2$O$_3$ can be gas-pressure sintered to theoretical density. While commonly a combination of sesquioxides is used such as Al$_2$O$_3$-Y$_2$O$_3$, the oxynitrid additives offer the advantage that only a nitrogen atmosphere is require instead of a powder. By starting form a mixture of ${\beta}$-SiC and ${\alpha}$-SiC, and by performing dedicated heat treatments after densification, anisotropic grain growth is obtained which leads to a platelet microstructure showing enhance fracture toughness. In the present work, recent improvement of the mechanical behaviour of these materials at ambient and high temperatures is reported. By means of a surface oxidation treatment in air it is possible to obtain four-point bending strengths in excess of 1 GPa, and the strength retention at high temperatures is significantly improved.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.31-38
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• 2003

A pilot scale biofilter pretreatment-microfiltration system (BF-MF) was operated to investigate the effect of biofilter treatment in fouling reduction of microfiltration. Biofiltration was expected to reduce the membrane fouling by removal of turbidity and metal oxides. The hollow-fiber MF module with a nominal pore size of 0.1$\mu$m and a surface area of 8m$^2$ was submerged in a filtration tank and microfiltration was operated at a constant flux of 0.5 m/d. Biofiltration using polypropylene pellets was performed at a high filtration velocity of 320 m/d. Two experimental setups composed of MF and BF/MF, i.e., without and with biofilter pretreatment, were compared. Throughout the experimental period of 9 months, biofilter pretreatment was effective to reduce the membrane fouling, which was proved by the result of time variations of trans-membrane pressure and backwash conditions. The turbidity removal rate by biofiltration varied between 40% to 80% due to the periodic washing for biofilter contactor and raw water turbidity. In addition to turbidity, metals, especially Mn, Fe and Al were removed effectively with average removal rates of 89.2%, 67.8% and 64.9%, respectively. Further analysis of foulants on the used membranes revealed that turbidity and metal removal by biofiltration was the major effect of biofiltration pretreatment against microfiltration fouling.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.98-103
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• 2007

In the present study, the author intended to investigate whether Gamiyukgunja-tang (Jiaweiliujunzi-tang, GYGT) significantly affect both mucin release from and MUC5AC gene expression in cultured hamster tracheal surface epithelial (HTSE) cells. Confluent HTSE cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of GYGT to assess the effect on 3H-mucin release. Possible cytotoxicity of the agent was assessed by measuring lactate dehydrogenase (LDH) release. Total elution profiles of control spent media and treatment sample through Sepharose CL-4B column were analysed and effect of GYGT on MUC5AC gene expression in cultured HTSE cells were investigated. GYGT did not affect mucin release from cultured HTSE cells. GYGT did not show significant cytotoxicity. GYGT also did not affect the secretion of the other releasable glycoproteins with less molecular weight than mucin. GYGT increased the expression level of MUC5AC gene. We suggest that the effect of GYGT with their components should be further investigated through ongoing research.

• Membrane and Water Treatment
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• v.2 no.3
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• pp.147-158
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• 2011

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/$dm^3$, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of $NH_3$ also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/$dm^3$. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two-fold concentration to achieve the concentration 2.4-2.6 g $SO{_4}{^{2-}}/dm^3$ and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed $CaSO_4$ and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.89-93
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• 2002

The physiology and morphology of cornea has effected on the ocular refractive status. Therefore the measurement of the anterior corneal surface by keratometer is used the treatment of the spectacles and contact lens by optician, optometrist, and ophthalmologist. Furthermore, currently the most corneal topographic mapping system have used the clinical optical shop, eye research center, and eye hospital. Because this method have a very fine data comparative to the previous instrument. The authors have measurement the cornea of the man college students by the corneal topographic mapping method. Especially this data will applied the clinical practice for the contact lens fitting. Especially in Korea, many man college students use the contact lens for the visual acuity and a beauty. Therefore the contact lens wear have increase per every year.

• Clean Technology
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• v.6 no.1
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• pp.39-49
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• 2000

Ultra Rapid Coagulation (URC) can dramatically remove pollutants loaded in wastewater by adding weighted coagulation additives (WCA) and recycling sludge into the coagulation basin to increase settling velocity and surface adsorption ability of floc. Also settling chamber together with lamella plates offers the high rate settling velocity, which can economically treat a considerable amount of pollutants like as combined sewage overflow (CSO) during the heavy rainfall and reduce the pollutants load into the receiving water for securing water source. It was estimated optimal configuration of settling chamber by using fluent model and the possibilities of reusing the sludge generated in this system.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.176-184
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• 2016

Electrochemical ion exchange method is expected to be one of the most acceptable techniques for the separation of radioactive cations from nuclear wastewater. In this study a thin film of hexacyanoferrate on nickel surface was derivatized chemically in an aqueous potassium-ferricyanide solution. Electrochemical redox behavior of the nickel hexacyanoferrate(NiHCNFe) film electrode was investigated with the use of cyclic voltammetry potentiostated from -100 to 800 mV versus SCE. The electro-reduction characteristics of the NiHCNFe film were examined in the cobalt solutions. The NiHCNFe ion exchanger was more useful at lower concentration, lower temperature, and pH7 of the cobalt solution. The capacity loss of NiHCNFe was 0.018%/cycle that was less than the average loss of 2~3%/cycle of the convective organic exchanger. The 45~55% of the initial cobalt ions was electro-deposited on the NiHCNFe by using continuous recirculating reactor system. As a result, it was found that the electroactive NiHCNFe films showed better performance than the organic resins for the separation of cobalt ion from the aqueous solutions.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.811-815
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• 1997

The present work describes the effect of dry grinding of a mixture composed of $Y_2O_3$, $BaCO_3$ and CuO powders with a planetary ball mill before heat treatment on crystal structure and superconductivity in the $YBa_2Cu_3O_{7-y}$. The specific surface area of the ground product of mixture decreased with an increase in the grinding time, after showing an upward trend up to 60 minutes of grinding. The critical current density, which was influenced by the grinding time of mixture, indicates the maximum value of about $150A/cm^2$ in the case of 60 minutes grinding, while the critical temperature, which were around 90K, for the sintered bodies were almost independent of the grinding time.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.29-29
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• 2003

Incompatible plant-pathogen interactions result in the rapid cell death response known as hypersensitive response (HR) and activation of host defense-related genes. To understand the molecular and cellular mechanism controlling defense response better, several approaches including isolation and characterization of novel genes, promoter analysis of those genes, protein-protein interaction analysis and reverse genetic approach etc. By using the yeast two-hybrid system a clone named Tsipl, Tsil -interacting protein 1, was isolated whose translation product apparently interacted with Tsil, an EREBP/AP2 type DNA binding protein. RNA gel blot analysis showed that the expression of Tsipl was increased by treatment with NaCl, ethylene, salicylic acid, or gibberellic acid. Transient expression analysis using a Tsipl::smGFP fusion gene in Arabidopsis protoplasts indicated that the Tsipl protein was targeted to the outer surface of chloroplasts. The targeted Tsipl::smGFP proteins were diffused to the cytoplasm of protoplasts in the presence of salicylic acid (SA) The PEG-mediated co-transfection analysis showed that Tsipl could interact with Tsil in the nucleus. These results suggest that Tsipl-Tsil interaction might serve to regulate defense-related gene expression. Basically the useful promoters are valuable tools for effective control of gene expression related to various developmental and environmental condition.(중략)

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.345-350
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• 2014

A special usage impeller pump for ballast water treatment is part of an offshore plant's structure. It has to maintain a high corrosion resistance in an extreme environment, in which it can contact several kinds of aqueous solutions. The duplex stainless steel used in such severe environments is known to have corrosion resistance and excellent mechanical properties. This study estimated the performance of an impeller pump system designed using duplex stainless steel through a computational fluid dynamics analysis. As a result, it was determined that the pressure drop increases and the impeller performance is lowered if the equivalent roughness is enlarged. The surface precision of the duplex stainless steel must be consistently maintained. If thisis the case, it was determined that the existing STS steel can be substituted for the Duplex stainless steel.