• Korean Journal of Computational Design and Engineering
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• v.17 no.1
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• pp.1-6
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• 2012

The End Coupling is main component of the aluminum hot roll process. The End Coupling is used for transmission of rotational power with heavy-duty load. Fracture of the End Coupling cause serious economic losses because an End Coupling is a very expensive component and it takes a long time to repair it. Therefore, preventing the destruction of the End Coupling is essential for ensuring a long mechanical life cycle. In this paper, the parametric study on the End Coupling was performed in order to minimize maximum stress under operation loads. To verify the interference of spindle assembly with modified End Coupling, kinematics simulation was performed by applying the various combination type and dynamic boundary condition of the spindle assembly. The interference of optimized model was not occurred during combination process and driving process. As a result of an optimum design for life extension on End Coupling, the maximum stress of modified End Coupling was lower than that of the initial model by 26%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.61-64
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• 2009

A study on the variation of combustion performance by oxidizer/fuel ratio was conducted. Shower head type injector was used. Injector propelled by liquid kerosene and liquid hydrogen peroxide. The designed operation condition for thrust and combustion pressure were 200N and 10bar. It is found that optimum oxidizer/fuel ratio.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.153-157
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• 2001

Operation conditions for the generation of an HF laser driven by fluorine-hydrogen combustion were discussed by mc:asuring the intensities of excited HF* molecules. Optimum injection quantities of fluorine gas for the generation of fluorine atoms was two times the injection mole number of hydrogen fuel. Slit nozzles with two dimensional configuration were used for the production of excited HF* molecules. When the injection mole number of secondary hydrogen gas is 1.3 times the injection mole number of fluorine gas, the fluorescence intensities of excited HF* molecules show maximum values. alues.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.49-54
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• 2002

This study was conducted to evaluate the feasibility and characteristics of poly acrylamide (PAA) immobilized sludge as a microbial entrapment bead for wastewater treatment. In the PAA method of immobilized sludge, it was found that the optimum acrylamide concentration for actual wastewater treatment was to be 12%. When the sequencing batch reactor (SBR) was operated during 30 days, removal efficiencies of TOC and phosphate was 95% and 70ft, respectively. From this research, repeated cycle of anaerobic and aerobic conditions is required to enhance the removal of TOC and phosphate. During the operation, immobilized cells could be used without being disrupted.

• KIEAE Journal
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• v.7 no.4
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• pp.51-56
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• 2007

This study focuses on developing natural ventilation system which is able to satisfy the good indoor air quality and air speed. The natural ventilation system developed in this study is for double window façade and it has two operation modes for summer and winter. Operational sections of the devices have been analyzed by CFD simulation to calculate discharge coefficients of openings and estimated indoor air speed. For the analysis of the appropriate installation area ratio for each room and the optimum installation area, TRNFLOW simulation has been used. As the results, we could see that the natural ventilation system can provide the similar pollutant removal performance to 0.7 ACH of mechanical ventilation with appropriate installation area and installation area ratio.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.5-10
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• 2002

We have analized the inverse class-F and class-F amplifiers using their waveforms. From the analytic equations derived from the analysis, we have calculated tole efficiencies, output powers, DC power dissipations, and optimum fundamental load impedances of the inverse class-F and class-F amplifiers. We also have compared them for various operation conditions, which include the same peak current, saute DC power dissipation, same fundamental RF output power, and same fundamental load impedance with different Ron(on-resistance). These analyses have clearly shown the performance limitations, advantages, and guide to the optimized design of the inverse class-F amplifiers.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.864-871
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• 2008

The tilting trains can run on curve track about 30% faster than conventional train without affecting passenger comfort. As the tilting trains offer the optimum means of providing faster and more comfortable rail service with minimum of environmental disturbance and capital investment, it is widely adopted for commercial operation all over the world. Over several years, the Korea Railroad Research Institute(KRRI) and Ministry of Construction and Transportation(MOCT) have been developing 200 km/h Korean tilting train, Hanvit200. Hanvit200 adopts the pendulum type tilting mechanism and hybrid car body structure, mainly CFRP combined with steel. In this paper the vibrational characteristics of Hanvit200 was investigated through Eigen vector analysis, modal test and main line running test.

• 연구논문집
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• s.27
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• pp.141-151
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• 1997

Recently, the importance of electro-multifunction control valve which is digital control valve is increasing day after day. This is due to the demand of that the current industrial world wants the valve having simpler control circuit and higher operation reliability. It is the PWM controlled high speed electronic valve that satisfies the damands of current industrial world. But, the PWM controlled high speed electronic valve has some non-linearity characteristics like as the delay time of switching and the pressure oscillation phenomenon. These characteristics are an obstacle for the control of high speed & high efficiency in control system. Therefore, in this study, we set the studying purpose on analysis of parameter characteristics in solenoid, and on establishment of optimum design technique in high speed solenoid.

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.701-708
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• 1993

Pd-doped SnO2 thin films for hydrogen gas sensing were fabricated by reactive fo magnetron sputtering and were studied on effects of film thickness and Pd doping content. Pd doping caused the optimum sensor operation temperature to reduce down to ~25$0^{\circ}C$ and also enhanced gas sensitivity, compared with undoped SnO2 film. Gas sensitivity depended on the film thickness. The sensitivity increased with decreasing the film thickness, showing maximum sensitivities at the thickness of 730$\AA$ and 300~400$\AA$ for the undoped SnO2 and the Pd-doped SnO2 film, respectively. Further decrease of the film thickness beyond these thickness ranges, however, resulted in the reduction of sensitivity again.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.497-498
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• 2008

An integrated Mach-Zehnder interferometer for biosensor applications was designed and fabricated. To implement the optimum biosensor a rib waveguide must have single mode operation and high sensitivity. The proposed Mach-Zehnder interferometer was fabricated based on these design rules, and its feasibility is confirmed by ethanol detection experiment in the real-time measurement system operating at 632.8 nm.