• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.5 no.1
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• pp.43-48
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• 1987

The terrain is classified by the parameters-gradient, curuature, bump frequency and the ratio of the surface area to the corresponding planar area- that indicate the quantitative measurement of the terrain roughness, and the terrain is fitted to the polynomial function. According to the terrain roughness, the flat terrain, the gently undulating terrain, the rough terrain are classified The flat terrain, the gently undulating terrain and the rough terrain are fitted to the plane function, the 3th or 5th polynomial function and the 5th polynomial function, respectively.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.281-285
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• 2005

Viscous solutions of supersonic jet impinging on a flat wall in a confined plenum are simulated using three-dimensional Navier-Stokes solver. A confined plenum was designed for simulating the missile launch and analyzing the behavior of the exhaust plume, which were accompanied by complex flow interactions with shock and boundary layer. Concerns of this paper are to show accurate simulation of internal flow in confined plenum and to demonstrate the jet flow structure when the jet interacts with a small opening on the side. Objectives of this numerical simulation are to understand the effect of changing the plume exit area of the plenum. Pressure and temperature rise at certain position in the plenum are traced and compared with test data.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.125-133
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• 1995

Rene80 superalloy was liquid phase diffusion bonded by using pure boron (B) as an insert material. As a basic study for the possibility of practical application of this bonding method, hardness and high temperature tensile strength of the bonded joint and metallurgical analysis were investigated. As experimental results, hardness of the bonded joint was homogenized after bonding and the tensile strength at 1144K was obtained to 90% of that of base metal. But there were some problems to be improved also, that means the joint was hardened after bonding due to increase of B content and elongation was much lower than that of base metal. Flat area and (Mo, Cr, W) boride, which should be harmful for bonding strength, were observed on the fractured surface of the tensile tested specimen.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1281-1283
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• 2003

Proteins in highly oriented lipid bilayer samples are useful to study membrane protein structure determination. Planar lipid bilayers aligned and supported on glass slide were prepared. These stack of glass slide with planar lipid bilayers are not well fit for commercial solid-state NMR probe with round coil. Therefore, homebuilt solid-state NMR probe was built and used for a stack of thin glass plates and RF coil is wrapping directly around the flat square sample. The overall filling factor of the coil is much better and the large surface area enhances the extent to orientation by providing uniform environments for the phospholipids and the high ratio of circumference to area reduces edge effects. $^1H\;and\;^{15}N$ double resonance probe for 400 MHz NMR (9.4T) with a flat coil (coil size: 11 mm ${\times}$ 20 mm ${\times}$ 4 mm) is constructed and tested.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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• pp.10-18
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• 2000

This paper describes the magnetic orientation of the intact and demembranated bull sperm treated by DTT or heparin in a 5,400 G static field. Semen samples collected from four bulls (Japanese Black) were mixed to the same sperm density. One percentage triton X-100 was used to extract the plasma membrane. The intact and demembranated sperm suspensions were treated with 20, 200, 2,000 mM DTT, 100, 1,000 or 10,000 units heparin solutions at $4{^{\circ}C}$ for 6 days. The decondensation of the sperm nuclei treated by DTT or heparin was examined by measuring the sperm head area at 1, 3, and 6 days. After measuring the area, each sperm sample was exposed to a 5,400 G static magnetic field generated by Nd-Fe-B permanent magnets for 24 hours at room temperature. Results showed that the decondensation of bull sperm nuclei was not induced by the heparin treatment, however, incomplete decondensation was induced by the DTT treatment. During the magnetic orientation, bull sperms treated by DTT or heparin had low percentages of long axis perpendicular to the magnetic lines of force. However, different aspects were obtained for long axis perpendicular orientations following treatment of DTT or heparin. Through the DTT treatment, the decline of long axis perpendicularly oriented percentages was due to the increase of long axis parallel orientation with the head of the flat plane perpendicular to the magnetic lines of force, whereas, using the heparin treatment, the decline of long axis perpendicular orientation was due to the increment of long axis parallel orientation with the head of the flat plane parallel to the magnetic lines of force. Also, percentages of the head of the flat plane perpendicular were decreased by the heparin treatment. These findings suggest that maintaining the structure of protamine in the chromatin is necessary for the sperm head to orient with its flat plane perpendicular, and maintaining the disulfide bond in the chromatin is necessary for the long axis of sperm to orient perpendicularly.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.7
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• pp.649-658
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• 2005

Flow condensation heat transfer coefficients (HTCs) of R22, R410, Propane (R290) were measured inside a horizontal 9 hole aluminum multi-channel flat tube. The main test section in the refrigerant loop was made of a 0.53m long multi-channel flat tube of hydraulic diameter of 1.4 mm. Refrigerant was cooled by passing cold water through an annulus surrounding the test section. Data were obtained in qualities of $0.1\~0.9$ at mass flux of $200\~400kg/m^2s$ and heat flux of $7.3\~7.7kW/m^2$ at the saturation temperature of $40^{\circ}C$. All popular heat transfer correlations in single-phase subcooled liquid flow and flow condensation originally developed for large single tubes predicted the present data of the multi channel flat tube within $25\%$ deviation when effective heat transfer area was used in determining experimental data. This suggests that there is little change in flow characteristics and patterns when the tube diameter is reduced down to 1.4 mm diameter range. Hence, a modified correlation based on the present data was proposed which could be applied to small diameter tubes with effective heat transfer area. The correlation showed a mean deviation of less than $20\%$ for all data.

• The Journal of the Korean bone and joint tumor society
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• v.4 no.2
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• pp.81-87
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• 1998

Although autoclaved autogenous bone reconstruction is one of the established procedures, it may have some problems in bone regeneration and mechanical property. The purpose of this study is to evaluate the efficacy of more biologic and anatomical reconstruction where allograft is not readily available. From Aug.1991 to Feb. 1996 the authors analyzed 32 cases of reconstruction with autogenous low heat treated bone. Autogenous graft sites were humerus 4, tibia 4, pelvis 9, and 15 femur. Average follow-up period was 23(range;12-51) months. There were 49 graft-host junctional sites. Diaphysis was 22, metaphysis 10, and flat bone 17. Average duration of healing for the 38 united sites was 7 months. Average union time for each anatomical area 8 months in 19 diaphysis, 12 months in 7 metaphysis, and 12.7 months in 12 flat bone(pelvis). Eleven nonunion sites consisted of 3 diaphysis(3/22), 3 metaphysis(3/10), and 5 flat bone(5/17). Complications other than nonunion were local recurrence(4), bone resorption(3), graft fracture(2), osteomyelitis(1), metal failure(2), and wound infection(1). Initial bone quality and stable fixation technique was important for union rate. Plate and screw is a good method for diaphyseal lesion. Metaphyseal and flat bone are weak area for rigid fixation and one stage augmentation with iliac bone graft can be a salvage procedure.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.249-255
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• 2005

Flow condensation heat transfer coefficients(HTCs) of R22, R4IO, Propane(R290) were measured inside a horizontal 9 hole aluminum multi-channel flat tube. The main test section in the refrigerant loop was made of a 0.53 m long multi-channel flat tube of hydraulic diameter of 1.4 mm. Refrigerant was cooled by passing cold water through an annulus surrounding the test section. Data were obtained in qualities of 0.1 ${\sim}$ 0.9 at mass flux of $200{\sim}400$ $kg/m^2s$ and heat flux of $7.3{\sim}7.7$ $kW/m^2$ at the saturation temperature of $4^{\circ}C$. All popular heat transfer correlations in single-phase subcooled liquid flow and flow condensation originally developed for large single tubes predicted the present data of the multi channel flat tube within 25% deviation when effective heat transfer area was used in determining experimental data. This suggests that there is little change in flow characteristics and patterns when the tube diameter is reduced down to 1.4 mm diameter range. Hence, a modified correlation based on the present data was proposed which could be applied to small diameter tubes with effective heat transfer area. The correlation showed a mean deviation of less than 20% for all data.

• Journal of the Korean earth science society
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• v.27 no.3
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• pp.328-340
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• 2006

In Janghwa-ri of Kanghwa Island morphological changes in four transects, 112 surface, and 2 core sediments were analyzed to understand the seasonal variation of the muddy tidal-flat environment. Sedimentary of facies can be classified into four facies; sand, muddy sand, sandy mud, and silt. During winter, the coarse-grained sediment facies expanded seaward. In the subsurface part of the core sediments, poorly sorted silty sediments dominate the area. According to the Pb-210 isotope analysis, accumulation rates of the tidal flat in Jangwha-ri appear to be $5{\sim}19mm/yr$. In the study area, the result is suggestive of a rapid change in depositional environments in recent years.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.99-106
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• 2002

For the development of a ultra-precision CNC polishing system including on-machine measurement system, we study a corrective polishing algorithm. We calculated unit removal profiles for various flat type polishing tools and polishing tool positions. Using these results we simulate the corrective polishing process based on dwell time control. We calculate dwell time distributions and residual error of the polishing simulation method and the FFT calculation method. We test corrective polishing algorithm with an optical glass. The target removal shape is a sine wave that has amplitude 0.3 micro meters. We find this polishing process has a machining resolution of nanometer order and is effective for sub-micrometer order machining. This result will be used for the software development of the CNC polishing system.