• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.301-309
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• 2000

This clinical study was made of 214 cases of the jaw cysts which were diagnosed histopathologically in the Department of Oral and Maxillofacial Surgery, Wonkwang University Dental Hospital from Jan. 1, 1991 to Dec. 31, 1998. Medical records, radiographs, histopathological reports of 214 cases with jaw cysts were retrospectively reviewed. The results were as follows : 1. Among the total patient of 214 cases, male were 143 cases, and female are 71 cases, male predominated by the ratio of 2.04. 2. The periapical cysts and the dentigerous cyst are the most common cyst, irrespective of 116 cases(54.2%) and 58 cases(27.1%). 3. The periapical cyst has no gender prediction, male were 70 cases and female were 54 cases, the mean ages were 39.3 years(SD=18.4). The most common involving teeth were maxillary anterior teeth(59.7%). 4. The dentigerous cyst predominantly occurred in third decade (18 cases : 31%), and the mean ages were 31.9 years(SD=14.8). Dentigerous cysts predominantly occurred in male by the ratio of 7.29 (male : 51 cases, female : 7 cases). Maxillary anterior teeth(43.1%) and mandibular molars(32.8%) were most frequently involved. 5. The odontogenic keratocyst predominantly occurred in second and third decade and mean ages were 23.5 years(SD=17.2). The mandibular molars(60%) were most frequently involved. 6. All nasopalatine cyst occurred after fourth decade, mean ages were 49.5years(SD=10.4). In the gender incidence of nasopalatine cyst, 1 case occurred in female and 10 cases occurred in male. 7. In the surgical intervention of jaw cyst, cyst enucleation and marsupialization performed in 156 cases. Cyst enucleation with bone graft performed in 58 cases and iliac autogenous bone grafts most frequently performed in 29cases. 8. The diameter range of cyst enucleation with bone graft were from 15mm to 120mm with a cyst diameter of 33.3mm. (SD=15.2) The diameter range of cyst enucleation and marsupialization were from 7mm to 82mm with a cyst diameter of 20.4mm.(SD=9.0) The diameter of cyst enucleation with bone graft were significantly greater than diameter of cyst enucleation. (p<0.05) 9. Post-operative complications occurred in 9 cases(15.5%) in which cyst enucleation with bone grafts performed and occurred in 31 cases(19.9%) in which cyst enucleation.

• Water Engineering Research
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• v.1 no.2
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• pp.119-127
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• 2000

In the process of crossflow microfiltration, a deposit of cake layer tends to form on the membrane, which usually controls the performance of filtration. It is found, however, that there exist a condition under which no deposit of cake layer is made. This condition is called the sub-critical flux condition, and the critical flux here means a flux below which a decline of flux with time due to the deposit of cake layer does not occur. In order to study the characteristics of the critical flux, a numerical model is developed to predict the critical flux condition, and is verified with experimental results. For development of the model, the concept of effective particle diameter is introduced to find a representative size of various particles in relation to diffusive properties of particles. The model is found to be in good match with the experimental results. The findings from the use of the model include that the critical flux condition is determined by the effective particle diameter and the ratio of initial permeate flux to crossflow velocity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1026-1031
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• 2008

We report on the design and experimental results of a large diameter faraday rotator for the high-power laser system(KLF: Kaeri laser facility) that was completed in late 2007s at Korea Atomic Energy Research Institute. The design involves modelling the magnetic field of cylindrical coil with large diameter(110 mm). Magnetic field generation coil is designed by 6 layers using a rectangular wire with cross-sectional area $3{\times}5[mm^2]$. We obtain an isolation ratio for optical feedback of 35 dB at 1064 nm and magnetic field strengths ${\sim}25kG$. We expect that the design can be widely used optical isolators in high-power laser system.

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.62-65
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• 2011

Characteristics of the pressure drop in an expanded bed have been compared to those in a packed bed for numerical study of the interphase drag in gas-particle flows. A numerical analysis of the pressure drop by the particle drag has been conducted according to the tube-to-particle diameter ratios and Reynolds numbers for comparison. As the tube-to-particle diameter ratios increase at the same Reynolds number, the pressure drop tends to converge. It has been confirmed that characteristics of the pressure drop in the expanded bed are similar to those in the packed bed.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1214-1221
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• 2011

It is an well-known fact that dynamic properties should be considered in design and maintenance of civil structures undergoing dynamic force such as rail track. For designing of the rail tack structures, dynamic properties of track bed soil such as shear modulus (G) and damping coefficients(D) obtained in small to medium range of shear strain must be known. In general, small size sample of D=5 cm and H=10cm has been used mostly for test convenience. However, ratio of largest particle diameter of the soil to sample diameter is very important and affects to the values of dynamic soil properties in track bed. In this study, an RC/TS test apparatus was built and was run for testing a medium size soil sample that can handle with compacted soil sample up to 10 cm diameter and 20 cm height.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.777-782
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• 2001

In this study, we used In-line orifice mixer for efficient chemicals mixing in water treatment. The method of using In-line orifice mixer has been already proved the improvement of water treatment efficiency. Numerical study was performed using FLUENT, a commercial code, to standard design and production of effective In-line orifice mixer. As variable for exactly standardizing, a proper ratio between an outer diameter of cone and a diameter of pipe, a distance between cone and orifice, a determination of orifice diameter for an optimal mixing, a distance between injection nozzle's position and cone, Numerical study has been performed for optimal standard and analyzed flow field on a basis of turbulent intensity in an orifice downstream.

• The KSFM Journal of Fluid Machinery
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• v.12 no.1
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• pp.51-56
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• 2009

The detailed heat transfer coefficient on a rotating dimpled channel were measured using the transient liquid crystal technique. The channel height to dimple diameter was 2, dimple center distance to dimple diameter was 1.5 and channel aspect ratio was 4. Tested Reynolds number based on the channel hydraulic diameter was varied from 15000 to 35000 and corresponding rotation number was ranged from 0.026 to 0.057. Results showed that the Coriolis force by rotation enhanced the heat transfer coefficient on the trailing surface. As the Reynolds number increased, i.e. rotation number decreased, the heat transfer coefficient increased and the thermal performance factor decreased.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.14 no.1
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• pp.2-8
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• 2006

Numerical analysis of the flow field in the reactive medium of End-Burring combustor is studied in order to investigate the combustion characteristics of hybrid combustion. The main part of this study is focused on the port diameter effects of oxidizer injector on the temperature distribution within the reactive field. It is found that the case having the largest port diameter(25 mm) delivers the optimum conditions for the design of End-Burring combustor where the predicted temperature field showed the most acceptable distribution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.914-917
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• 2002

Fabrication of micro carbon structures and patterns using laser-assisted chemical vapor deposition is studied. Argon ion laser and ethylene were used to grow micro carbon rod through pyrolytic decomposition of the reaction gas. The influence of reaction gas pressure and incident laser power on the diameter and growth rate of the micro carbon rod was experimentally investigated. The diameter of micro carbon rods increases linearly with respect to the laser power but is almost independent of the reaction gas pressure. Growth rate of the rod changes little with gas pressure when the laser power remains below 1W. When the carbon rod was grown at near threshold laser power, a very smooth surface is obtained on the rod. By continuously moving the focusing lens in the direction of growth, a micro carbon rod with a diameter of 28 ${\mu}{\textrm}{m}$ and aspect ratio of 100 was fabricated.

• Journal of computational fluids engineering
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• v.7 no.2
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• pp.1-7
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• 2002

The present study is developed device that effectively mixes raw water and chemicals by using the residual head of fluid in the front pipe of flocculation basin, and performed non-dimensional analysis and presented design standard to apply to water plants that have different equipment capacity. The variables for design are a proper ratio between an outer diameter of deflector and a diameter of pipe, a distance between deflector and orifice and a determination of orifice diameter for an optimal mixing. Numerical study has analyzed flow field on a basis of turbulent intensity in an orifice downstream. As Reynolds number of In-Line Orifice was increased from identical design variable, the turbulent intensity of pipe center was no changed almost.