• Journal of computational fluids engineering
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• v.16 no.2
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• pp.66-74
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• 2011

The SCR catalyst in coal-fired power plant is eroded by the collision of fly ash on the catalyst surface. However the erosion of SCR catalyst by the collision of fly ash has not been fully studied, especially in terms of fluid dynamics. Hence, in the present study, we focus on the gas and solid flows inside the SCR catalyst duct and their consequent effect on the erosion characteristics. For this purpose, computational fluid dynamics is applied to investigate the two-phase flows and to evaluate the erosion rate for different flow and particle injection conditions. Also, the erosion rate and pressure drop of commonly used square shape are compared with equilateral triangle and hexagon shapes. The pressure drop of SCR catalyst is increased when SCR catalyst surface area per unit volume increases. The erosion rate of SCR catalyst is enhanced when the particle velocity, mass flow rate of particle, particle diameter and cell density of SCR catalyst are increased. From the results, the pressure drop and erosion rate at the catalyst surface can be minimized by reducing cell density of SCR catalyst to decrease particle velocity and number of particle impacts.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.133-140
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• 1999

The relationships between discharge characteristics and sustain electrode shape are studied in AC PDP by calculating the electric field and measuring discharge voltage, luminance and current. The maximum electric field is obtained for the triangle shape electrode. It is 1.8 times larger than uniform electric field type. It has been shown thatthe firing voltage is largely affected by the degree of electric field concentration. But, as the difference of the maximum and minimum value of electric field in a cell increases, the luminance and luminance efficiency decrease. And, the charge variation during discharge is proportional to the area of electrode.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.158-165
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• 2022

Eco-friendly policies proposed by the government of The Republic of Korea have encouraged the use of eco-friendly vehicles. Hydrogen vehicles have exhibited the highest growth rate, although the current number of registered vehicles is low. In hydrogen vehicles, a thermally activated pressure relief device (TPRD) is installed to prevent explosions in the hydrogen gas cylinder. When discharged due to low ignition energy, hydrogen gas readily forms a jet flame. The risks induced by such jet flames were analyzed through a numerical analysis. Jet flames can activate TPRDs installed in nearby hydrogen gas cylinders. As a result, high-voltage cables exposed in the lower area of a vehicle can ignite within seconds. There was a 9.5-kW/m2 area around the vehicle (which can result in casualties) at a distance of ~5 m from the hydrogen gas cylinder, and a 37.5-kW/m2 area (which can cause significant damage) in the form of an inverted triangle toward the lower section of the vehicle. We believe that the risk factors analyzed herein should be considered for addressing accidents in hydrogen vehicles.

• Journal of Korea Association of Health Promotion
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• v.4 no.1
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• pp.75-84
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• 2006

Background : Osteoporosis and atrophic cell pattern in Pap smear are frequent findings In postmenopausal women due to loss of ovarian function, The present study attempted to find out possible correlation between morphologic characteristics of Pap smear and osteoporosis. Material & methods: The subjects were 825 women(age from 35 to 80) who had undergone Pap smear and bone mineral density(BMD) at The Korea Association of Health Promotion, Seoul Branch, from March 8 to May 10, 2005. Pap smears from 825 women were reviewed and classified either mature cell pattern or atrophic cell pattern by their cytologic patterns, BMD were measured using LUNAR DPX MdIQ(Minster, Ohio, USA). BMD value of lumbar spine(Ll, L2,L3 and L4) were measured from 825 women and BMD value of proximal region off emur(neck NK, Wards triangle WT, and trochanter TR) were measured from 818 women and their bone status were classified as normal( T-sore:>-1.0), osteopenia (T-score: -l~<-2,5) and osteoporosis(T-score: ≤ -2.5). And age distribution of Pap smear, average T-value andfrequency ofsteoporo-sis of each region of the bone, percentage of osteoporosis of each boneregion by age group and changing pattern of percentage of osteopenia and osteoporosis in certain postmenopausal period were compared between mature and atrophic cell pattern. Results: Pap smears revealed total mature cell pattern 53,9%(445/825) and total atrophic cell pattern 46.1%(380/825), Percentage of mature cell pattern decreased from 98.2%(168/171)under 44 age group to 13,3%(17/128) over 65 age group and mature cell pattern increased from 1.8%(3/171) under 44 age group to 86.7%(111/128) oyer 65 age group. Mean T-value of each region of lumbar spine and femur of mature cell pattern were lower than that of atrophic cell pattern about -1,5. And osteoporosis has noted in atrophic cell pattern showing odds ratio Ll 13.9, L2 15.3, L3 12.0, L4 10,4, UK 6.7, WT 10.9 and TR 4.1.Atrophic cell pattern started to increase after 45 years of age and osteoporosis of a trophic cell pattern started after 55 years of age. During 50 to 64 years of age period, L3, L4 and WT revealed parallel increased of osteopenia and osteoporosis and Ll, L2 revealed decreased of osteopenia and increased of osteoporosis. nia Conclusion: Above findings suggest that atrophic cell pattern of Pap smear precedes osteoporosis about 10 years and one of predictor of osteoporosis.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.450-457
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• 1998

The cryparin of Cryphonectria parasitica belongs to a cell wall associated fungal hydrophobin. The cryparin, though it is encoded by a single copy gene, is known for the high expression during the liquid culture of C. parasitica, and it turns out that 22% of total mRNA was transcribed for cryparin at 48hr after the liquid culture. In addition, it is also known as one of down-regulated fungal proteins by the presence of double stranded RNA virus, Cryphonectria hypovirus 1. In previous studies (Kim et al., 1999), we have constructed a cryparin-null mutant by replacing the cryparin gene with hygromycin B resistance gene due to site directed homologous recombination. In order for the promoter analysis of cryparin which seems to be very strong as well as mycoviral specific, it is preferable to have a strain with only a target promoter replaced and a discernable target site for incoming vectors. However, the cryparin-null mutant revealed the presence of an additional copy of transforming vector except the one which replaced the cryparin gene. In addition, the cryparin-null mutant did not contain any markers for targeted integration of incoming vectors. This prompts us to design an experiment to obtain a strain for promoter analysis of cryparin gene. A different mating type strain EP6(Mata, $met^-$) was mated with the cryparin-null mutant ${\triangle}$Crp194-7(MatA, Crp${\triangle}$::hph) to make the progenies with only a single replacement vector and $met^-$ characteristic remained. Nutritional assay as well as Southern blot analysis revealed that the progeny, ${\triangle}$Crp194-a6, was the methionine auxotroph with a single replacing vector in genome. Northern blot analysis and PAGE showed that there was no cryparin produced in this bred strain either.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.77-82
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• 2004

A new anisotropic mesh refinement method is proposed. The new method is based on a simple second order interpolation error indicator. Therefore, it is methodologically direct and intuitive as compared with traditional anisotropic refinement strategies. Moreover, it does not depend on the mesh type. The error indicator is face-wisely calculated for all faces in a mesh and the cell refinement type is determined by the configuration of face markings with a given threshold. For the sake of simplicity, an application for a poisson equation on a triangle mesh is considered. The error field and resultant mesh refinement pattern are compared and effects of the threshold selection are discussed. Applying anisotropic refinement with various thresholds, we observed higher convergence rates than those in the uniform refinement cases.

• Journal of Sensor Science and Technology
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• v.14 no.6
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• pp.369-373
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• 2005

High quality CdTe single crystal for the solar cell fabrication was grown by vertical Bridgman method. The etch pits patterns of (111) surfaces of CdTe etched by Nakagawa solution was observed the (111)A compesed of Cd atoms with typical triangle etch pits of pyramid mode. From the photoluminescence measurement on (111)A, we observed free exciton ($E_{x}$) existing only high quality crystal and neutal acceptor bound exciton ($A^{0}$,X) having very strong peak intensity. Then, the full width at half maximum and binding energy of neutral acceptor bound exciton were 7 meV and 5.9 meV, respectively. By Haynes rule, an activation enery of impurity was 59 meV. Therefore, the origins on impurity level acting as a neutral acceptor were associated Ag or Cu elements.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.42-45
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• 2004

High quality CdTe single crystal for the solar cell fabrication was grown by vertical Bridgman method. The etch pits patterns of {111}surfaces of CdTe etched by Nakagawa solution was observed the {111} A composed of Cd atoms with typical triangle etch pits of pyramid mode. From the photoluminescence measurement on {111}A, we observed free exciton($E_x$) existing only higy quality crystal and neytral acceptor bound exciton($A^0$,X) having very strong peak intensity. Then, the full width at half maximum and binding energy of neutral acceptor bound exciton were 7 meV and 5.9 meV, respectively. By Haynes rule, an actibation energy of impurity was 59 meV. Therefore, the origins on impurity level acting as a neutral acceptor were associated Ag or Cu elements.

• Anatomy and Cell Biology
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• v.51 no.4
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• pp.299-301
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• 2018

Killian-Jamieson diverticulum is a permanent protrusion of anterolateral proximal esophagus through anatomically weak muscular gap, known as Killian-Jamieson area, into adjacent area. During a routine educational dissection, we found a well-defined lateral diverticulum just inferior to the transverse fibers of the cricopharyngeus muscle in a Korean male cadaver. It had a dimension of $1.8{\times}1.4{\times}1.0cm$ with two types of epithelial cells, stratified squamous and simple cuboidal to low-columnar epithelium, and attenuated and haphazardly arranged muscle fibers. No epithelial dysplasia or malignant transformation was identified except ulcerative changes. Although Killian-Jamieson diverticulum is a very rare disease, clinicopathological aspects should be considered.

• Journal of Sensor Science and Technology
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• v.18 no.6
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• pp.423-431
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• 2009

Standard uroflowmetry measures the urine weight using single load cell to evaluate the urinary flow rate. Impact noise should be introduced due to gravity when the urine stream falls down into the container upon the load cell. The present study placed three load cells on the three vertices of a regular triangle and the three signals were ensemble averaged to enhance the signal-to-noise ratio(SNR) regardless of how the urination was made. Simulated urination experiment was performed with three different urine collection methods. In all three methods, SNR of the averaged signal was much higher than each load cell signals. With no urine collection device, the present signal averaging technique resulted in SNR values higher by 10~15 dB than when dual funnels or upper funnel were used to guide the urine stream. Therefore, it was demonstrated that the three point measurement followed by with ensemble averaging could enable accurate uroflowmetric test without any specially made urine collection devices.