• Water for future
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• v.17 no.4
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• pp.293-302
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• 1984

The tidal and meteorological condition associated with wintertime surges in the Ease China Sea are described. The vertically-integrated finite difference model of the East china Sea have been used to investigate the surges generated during a period of 5 days in November, 1983 dynamically. Computed residual elevations are compared with hourly records form selected tide gauges along the west coast of Korea. Preliminary results on circulation pattern derived from the numerical model are presented and discussed. Further refinement of the model using current meter observation is presently being performed to provide more accurate information on bottom stress distribution.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.89-94
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• 2001

The position control accuracy of a robot manipulator is significantly deteriorated when a long arm robot is operated at a high speed. This paper presents a very simple sliding mode control which eliminates multiple mode residual vibration in a robot manipulator. The neural network is used to avoid that sliding mode condition is deviated due to the change of system parameter and disturbance. This paper is suggested control system which designed by sliding mode controller using neural network. The effectiveness of proposed scheme is demonstrated through computer simulation.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.185-192
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• 2002

A laboratory scale thermogravimetric analyser was developed to investigate the combustion characteristics of selected solid fuel(wood) in the highly preheated air. The aims are to introduce in the means of experimental determination of the solid fuel particle characteristics through the combustion process in the environment of highly preheated air. A nearly single particle combustion condition was reproduced in a thermogravimetric analyser and regenerating combustor. For a fuel particle whose characteristic length was a few centimeter, the sub-processes of fuel drying, pyrolysis as well as the combustion of residual carbon were identified. Fluidized environment of carrier gas was selected as the major parameter which affect the combustion process.

• Journal of Power System Engineering
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• v.5 no.1
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• pp.80-88
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• 2001

The spot welding method has been used in the joining of structures, automotive body, railway carriage, aircraft, household electric appliances, precision parts etc., because of brief working, easy automation, available mass production, and convenience. In this paper, the effects of welding conditions on the fatigue life and the prediction of fatigue life based on fracture mechanics theory of spot welded joint were investigated. Fatigue tests were conducted with the tensile-shear specimens welded in the various current using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. Using FEM(finite element method), we analysed the distribution of stress and the condition of deformation on the environments of nugget.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.04a
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• pp.93-96
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• 2009

The high grade thick plate is in great demand in the ship building industry and the construction industry. The main problems to produce the high grade plate are residual stress and flatness of plate. In the previous research, Finite Element Analysis(FEA) was conducted for cold roller leveler to understand the behaviors of cold roller leveler under different conditions of thickness, intermesh, and yield stress. In this study, a numerical model of roller leveler is developed and the calculated results of this model are compared with the FEA results to show the validity of the numerical model. The optimal leveling conditions to improve flatness of plate are suggested using this numerical model.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.04a
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• pp.48-51
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• 2009

Excessive wavy surfaces formed by a cold or hot-rolling process in a thin plate degrade the value of the plate significantly, which is called flatness problem in the industry. It is a result of post-buckling due to the residual stress caused by the rolling process. A unique difficulty of the problem as a buckling problem is that the buckling length is not given but has to be found. a new approach is developed to solve the flatness problem by extending a classic post-buckling analysis method based on the energy principle. The approach determines the buckling length and amplitude. The new solution approach can be used to determine the condition for the maximum rolling production that does not cause the flatness problem.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.153-159
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• 2002

Brittle materials such as ceramics and glasses show fragile fracture due to the low toughness and the crack sensitivity. When brittle materials are subjected to impact loading by small spheres, high contact pressure occurs to the surface of the specimen. Local damage is subsequently generated in the specimen. This local damage is a dangerous factor which gives rise to the final fracture of structures. In this research, impact damage of soda-lime glass plates by small spheres was evaluated by considering the effects of impact directions of indenter, pressure condition of specimen and residual strength after impact loading.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.456-459
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• 2005

Continuous cooling transformation behaviors were studied fur low carbon HSLA steels containing three different level $(1\~3\;wt\%)$ of Ni addition. Thermo-mechanical processing (TMP) simulations to construct continuous cooling (CCT) diagram were conducted by using Gleeble system. As cooling rate increased, pearlite, granular bainite, acicular ferrite, bainitic ferrite and lath martensite were transformed from deformed austenite. Fully bainitic microstructure were developed at all cooling rate condition in high Ni containing steel due to hardenability increasing effects of Ni. Ni also influenced the transformation kinetics. At the slowest cooling rate of $0.3^{\circ}C/s$, transformation delayed with decreasing Ni contents because of the diffusion of substitutional alloy elements. However, cooling rate slightly increased to $1^{\circ}C/s$, transformation kinetics accelerated with decreasing Ni contents because nucleation of bainite was sluggish due to hardening of residual austenite.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.243-245
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• 2005

Recently many research are going on in the field of application of Laser-Arc hybrid welding for superstructures such as shop-structures, transport vehicles etc. However, the study on heat distribution and welding residual stress of hybrid weld by numerical simulation leaves much to be desired. Therefore in this study an optimized welding condition and numerical simulation for hybrid welding by using previous numerical analysis which is used to calculate the heat source for hybrid welding has been analyzed.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.9-14
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• 2006

Deinking is a series of unit operations designed to detach ink from cellulose fibers and separate the dispersed ink from the pulp slurry. Deinking chemicals are process aids that enable expensive mill equipment used in these unit operations to operate more efficiently. This paper presents an overview of ONP deinking efficiency with cellulolytic enzymes and synthetic collector in low alkalinity process. The deinking efficiency of old news print even in low alkalinity condition was enhanced with enzyme contained complex agent. The brightness of deinked pulp was increased with less residual ink particles and yield of deinked pulp was improved compared to the deinked pulp of conventional alkaline method.