• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.15-20
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• 1996

The nonlinear dynamic analyses were performed by newly developing an appropriate impact modelling for the evaluation of the CANFLEX fuel bundle structural integrity during the refuelling period. The initial load under the refuelling condition is considered as initial velocity at impact incident, and the impact of one bundle contacted another bundle for at short time is studied by performing several dynamic analysis method. The impact analysis shows to predict an appropriate velocity and acceleration profile according to load time history for two bundles impact.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.56.2-56.2
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• 2011

As rotor blade of a wind turbine becomes larger to satisfy the economic efficiency for offshore wind farm, the numerical analysis considering wind profile is getting emphasized. In this paper, the study for the power characteristic of a wind turbine is carried out using NREL phase VI wind turbine applied wind profile. The experimental data of NASA Ames wind tunnel for inflow velocity 7m/s is used and the numerical result is obtained by using CFD commercial solver(FLUENT).

• Advances in Energy Research
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• v.4 no.2
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• pp.163-176
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• 2016

Rapid depletion of fossil based oil, coal and gas reserves and its greater demand day by day necessitates the search for other alternatives. Severe environmental impacts caused by the fossil fire based power plants and the escalating fuel costs are the major challenges faced by the electricity supply industry. Integration of Distributed Generators (DG) especially, wind and solar systems to the grid has been steadily increasing due to the concern of clean environment. This paper focuses on a new simple and fast load flow algorithm named Backward Forward Sweep Algorithm (BFSA) for finding the voltage profile and power losses with the integration of various sizes of DG at different locations. Genetic Algorithm (GA) based BFSA is adopted in finding the optimal location and sizing of DG to attain an improved voltage profile and considerable reduced power loss. Simulation results show that the proposed algorithm is more efficient in finding the optimal location and sizing of DG in 15-bus radial distribution system (RDS).The authenticity of the placement of optimized DG is assured with other DG placement techniques.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.883-890
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• 2005

In this paper, the established model of NBTI (Negative Bias Temperature Instability) mechanism was reviewed. Based on this mechanism, then, the influence of nitrogen was discussed among other processes. A constant concentration of nitrogen exists inside $SiO_2$ in order to prevent boron from diffusing and to increase dielectric constant. It was shown that NBTI improvement was achieved by controlling nitrogen profile. It was supposed that the existence of low activation energy of Si-N bonds at $Si-SiO_2$ interface attributes the improvement by making hydrogen prevent interface traps. It was also shown that improvement of NBTI can be achieved by more effective control of nitrogen profile. It was supposed that the maximum control of nitrogen profile can be achieved by DPN (Decoupled Plasma Nitridation) process.

• Journal of Welding and Joining
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• v.16 no.4
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• pp.117-124
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• 1998

During the reflow process in SMT, the molten solder has been observed to move upward and solidify along the gullwing lead, which is called the wicking phenomenon. In this paper, possible causes of the wicking are investigated, and its effects on the solder joint profile are quantitatively estimated by introducing the wicking constant. The free energy reduction by intermetallic formation between the copper and tin seems to be the major source of wicking action. The joint profiles of the gullwing lead are calculated using the previous finite element formulation incorporated with the wicking constant. The calculated results show reasonably good agreements with the experimental data when the wicking effects are considered.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.266-272
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• 1992

A coherent anti-Stokes Raman spectroscopy (CARS) technique is applied to measure temperature profile in a flame. The CARS signal is obtained with BOXCARS phase matching to get better spatial resolution. A program routine for calculating temperature of the flame from the measured CARS spectra is studied. The routine includes the line broadening mechnism of the molecules described with a modified energy gap (MEG) law by using the perturbation theory. We have found that the temperature profile obtained with the MEG law is properly fit with the results measured with a thermocoulpe and calculated with the adiabatic theory.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.251-258
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• 1999

This paper is mainly concerned with the development of the ATO(Automatic Train Operation) profile on precision stop controller. The ATO system is used for automatic or driverless operation of a train. In this paper, the algorithm for ATO controller is presented and three speed profiles on precision stop controller are compared. One profile is based on the maximum jerk control, another on the constant control input, and the third on the optimal control for the minimum energy consumption. These profiles are simulated and analyzed in view of the stop time, control input, jerk, propulsion and braking.

• Journal of Power Electronics
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• v.6 no.1
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• pp.83-93
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• 2006

A new high efficiency and low profile on-board DC/DC converter for digital car audio amplifiers is proposed. The proposed converter shows low conduction loss due to the low voltage stress of the secondary diodes, a lack of DC magnetizing current for the transformer, and a lack of stored energy in the transformer. Moreover, since the primary MOSFETs are turned-on under zero-voltage-switching (ZVS) conditions and the secondary diodes are turned-off under zero-current-switching (ZCS) conditions, the proposed converter has minimized switching losses. In addition, the input filter can be minimized due to a continuous input current, and an output inductor is absent in the proposed converter. Therefore, the proposed converter has the desired features, high efficiency and low profile, for a viable power supply for digital car audio amplifiers. A 60W industrial sample of the proposed converter has been implemented for digital car audio amplifiers with a measured efficiency of $88.3\%$ at nominal input voltage.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.242-242
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• 2010

Si(100) 표면에 이온을 일정한 에너지로 dose량을 동일하게 유지하고, dose rate만을 변화시켜가며 주입한 후에 depth profile과 damage, 그리고 sheet resistance를 조사하였다. 일정한 에너지로 이온을 주입하여도 dose rate의 변화에 따라서 depth profile에 변화를 보이는 것을 확인할 수 있었고 sheet resistance역시 dose rate변화에 비례하여 변화하는 것을 확인할 수 있었다. 본 연구는 Crystal-TRIM program으로 computer simulation 하여 damage profile의 결과를 통해 dose rate가 클수록 시료 표면 근처에 잔류 damage의 양이 높게 나타나는 것을 알 수 있었고 그 잔류 damage의 표면근방 분포가 sheet resistance에 직접적인 영향을 미친다는 것을 확인할 수 있었다.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.311-320
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• 2009

Most advanced countries are researching to apply light weight materials far rolling stock because weight reduction for railway body derives cost-saving, energy-saving, and high-speed. Likewise, current Korea rolling stock field makes arduous effects of weight-reduction, miniaturization, and high-efficiency to achieve a high-speed railway. Aluminum becomes suitable material for these projects because it is much lighter than steel or stainless. Manufacturing the railway car body by using the Aluminum is increasing because Aluminum is not bringing the corrosion by unique oxidation-passivate. Aluminum extrusion profile far railway body requires a high mechanical property, accurate shape dimension, and stable quality because the railway body is composed with many different kinds of extruded profiles. Therefore, it is necessary to research about Aluminum precision-extrusion technology to maintain exit temperature and die load. The goal of this project is applying the Aluminum extrusion profile to next-generation railway car body by developing the Aluminum extrusion profile according to precision-extrusion technology which may maintain isothermal exit temperature.