• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.201-206
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• 2003

Plastic injection mould have two kinds of trouble, one is in mould another in injection parts. Most of defects of the former take the cause in a design like in structure and working, the later weld line, transforming, sink mark, burning, flow mark, scratching, shading, black hole and so on. Most of problems of the later is difficult for making a clear definitely the reason of defects because of complexible. The purpose of this paper is to improve the quality of plastic injection mould and parts with inquiring the counter plan and rouble of the part of Flat TV Front Cover by flow control method and gas- assisted injection moulding. For minimizing defects from injection moulding parts, this paper was investigated with using computer aided injection mold filling simulations. Based on these numerical results, I established guidelines mould design and injection processing condition. As a results I got the improve of quality, minimizing surface defects moulded parts and troubles in mould.

• Proceedings of the KWS Conference
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• v.43
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• pp.150-152
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• 2004

This study was aimed at evaluation of residual stress of steel pipe structures. The production process of pipes was complex (at first bending was done by roll forming or press forming and welding was final process of making of steel pipes). So there could be effected high residual stresses in steel pipes. In order to evaluate the changes of residual stress the locations of measurement were selected carefully. Measurements of residual stress were done for various kinds of pipes (shapes in circular and square). For the evaluation of residual stress, hole-drilling method (ASTM E837 was applied. The results showed that along the weld Eine high tensile stress were measured as effected, and high tensile stresses were measured where large plastic deformation developed. Through these efforts, experimental results could be more effectively assisted by numerical method.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.51-54
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• 2008

In this study, we investigated variations in undoped ZnO thin film properties with working pressure, $O_2$/Ar ratio, and annealing ambient. Higher vacuum pressure during deposition was observed to bring about slower growth rate resulting in samples with better crystallinity as well as hole generation efficiency through formation of shallower oxygen interstitial. Given that $O_2$/Ar ratio is greater than unity, O provided from the ambient to ZnO during annealing was found to preferably situate at interstitial sites. When He was used for the second annealing, significant changes were not observed. On the other hand, O ambient caused increased density of oxygen interstitial, thereby making the film more intrinsic-like high resistivity ZnO.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.141-144
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• 2009

This paper presents an achieving method of highly progressive pressure gradient to enhance the missile ejection system's performance by using a gas generator. To obtain a stable burning, the decrease of a grain's L/D is proposed except making radial holes through the grain. New approach by applying adjustment of a grain's L/D reduces the maximum acceleration level by about 33% than that of reference model.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.147-155
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• 2010

On this paper, suggests a communication structure making possible to fast data send-receive for the gaming process synchronization. For these things, first of all, analyze the data send-receive speed effecting on the online game by the game genre. Moreover, we suggested a proper data communication structure like real-time online action game genre which gaming synchronization effects on the gaming process. Communication structure suggested on this paper is being used with TCP/UDP protocol, and it is applied to the network system and verify improved data send-receive speed. These data send-receive structure can be applied to the various online games.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.167-172
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• 2006

Recently, wire-EDM became a necessity for many engineering applications, particularly in the dies making. No-Core cut process is helpful for operations in which falling slug can jam the machine or wire. In this paper a proposed CAM system (called NCPP) is introduced, to overcome the limitations of the existing CAM systems in the machining of No-Core cut. The proposed CAM system (NCPP) provides pocketing of No-core cut and optimal selection of the position of starting hole (wire threading point), to minimize toolpath length. It was written for data exchange between CAD-CAM-CNC machines. This data model will become part of the ISO (Data model for Computerized Numerical Controllers) international standard. The NCPP system has been implemented in Visual C++. Many examples are used to illustrate NCPP system. The results show that, NCPP saves the machining time by significant value. This value depends on the shape and complexity of the workpiece that is being cut.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.79-87
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• 2016

Mobile fish-cage was developed assuming a cage net with an enclosed area, which and estimated the hydrodynamic characteristics of the cage through the model experiment. Flux-shielding plates, installed in the bow were compared with the resistance test carried out by making a hole, bilge keel and stud, and basic block flow rate consisting of the results to a flat surface plate. The experimental results confirmed the improved resistance performance effect of 3~6% in the bilge keel and the stud form. To assess the stability of the fish-cage, evaluation of the stability in accordance with the stability criteria for determining the floating docks had confirmed that it satisfied the static stability performance under operating conditions at sea.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1114-1119
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• 2004

The photodepositioned tungsten film by laser CVD has been carried out the taping test with scotch tape over 10 times. As a result, it exhibited strong adhesion to the under-film such as ITO and SiNx patterned on the LCD substrate. However, it was seriously attacked by alkaline solution used for removing polyimide. And a thickness of laser CVD tungsten film had a close relation to a speed of laser scanning. Also we have improved the success rate of a laser CVD repair with making two pairs of contact hole structure and decreasing laser scanning speed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.14-15
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• 2006

Application of the parallel Build-up is increasing continuously. This report presents about the PCB Build-up technology since 2000. Among the parallel build-up technologies, PALAP application - after making the via, filling the via with electric conductive paste, then expose to make wiring pattern and put them by layer without any glue or middle - is actively developing, especially DENSO company.

• Journal of Korean Neurosurgical Society
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• v.37 no.5
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• pp.386-388
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• 2005

The authors present a case in which an organized chronic subdural hematoma(CSDH) was incidentally found in a 9-year-old boy with no significant medical history after a pedestrian traffic accident. Preoperative magnetic resonance(MR) imaging showed calcification on the inner membrane and an irregular heterogeneous structure in the hematoma cavity. The findings from the preoperative brain computed tomogram(CT) and MR image were very useful for making the preoperative diagnosis and surgical decision. In choosing the proper surgical strategy for removing the organized CSDH, it was thought that burr hole trephination would present unnecessary difficulties. Thus, craniotomy was selected and the organized CSDH was successfully removed with no complications.