• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.277-278
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.287.2-287.2
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• 2008

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.79.3-80
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• 2015

Galaxy overdensities such as galaxy clusters and superclusters are the largest gravitationally bound systems in the Universe. Since they contain many different levels of local densities, they are excellent places to test galaxy evolution models in connection to the environments. The environment studies of galaxies at z ~ 1 are important because the environmental quenching seems to be an important mechanism to reduce star formation activities in galaxies at z < 1. However, there have been not many studies about high redshift galaxy clusters at z ~ 1 because of the lack of wide and deep multi-wavelength data. We have used the multi-wavelength data from the UKIDSS DXS (J and K band), the SWIRE (4 IRAC bands), and the PAN-STARRS (g, r, i, z, y bands) in the ELAIS-N1 field. We identified galaxy cluster candidates at 0.2 < z < 1.6 using the multi-wavelength data. We found several superclusters where cluster candidates are concentrated on few tens of Mpc scale. Interestingly, some of the supercluster candidates consist of galaxy clusters which have high blue galaxy. We will present high redshift galaxy cluster and supercluster candidates in ELAIS-N1 field and galaxy properties in different environments including dense clusters and fields.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2708-2715
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• 2021

The Multi-Purpose Overload Robot (CMOR) is a key subsystem of China Fusion Engineering Test Reactor (CFETR) remote handling system. Due to the long cantilever and large loads of the CMOR, it has a large rigid-flexible coupling deformation that results in a poor position accuracy of the end-effector. In this study, based on the Levenberg-Marquardt algorithm, the spatial grid, and the linearized variable load principle, a variable parameter compensation model was designed to identify the parameters of the CMOR's kinematics models under different loads and at different poses so as to improve the trajectory tracking accuracy. Finally, through Adams-MATLAB/Simulink, the trajectory tracking accuracy of the CMOR's rigid-flexible coupling model was analyzed, and the end position error exceeded 0.1 m. After the variable parameter compensation model, the average position error of the end-effector became less than 0.02 m, which provides a reference for CMOR error compensation.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1314-1317
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• 2006

The problem of the conflict between eye convergence and accommodation can be induced at Stereoscopic or multi-view 3D display system using binocular disparity. A multi-focus 3D display system was developed, which can solve the problem. LEDs are used instead of galvano scanner and laser to avoid mechanical moving part at the 3D display system.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1378-1383
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• 2018

Multi-wavelength holography has a better axial range than single-wavelength holography, thus allowing unambiguous phase imaging. Noise amplification is the limiting factor in multi-wavelength holography as noise is amplified by a factor equivalent to the magnification of the wavelengths. Here, we propose a new algorithm to remove noise amplification in multi-wavelength holography. The proposed method does not use phase unwrapping and removes $2{\pi}$ ambiguities. Experiments and numerical simulations indicated that the proposed method is fast, has low noise, and is useful for measuring samples with arbitrary step heights.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.2
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• pp.58-74
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• 2022

Deterministic accident analysis plays a central role in the nuclear power plant (NPP) safety evaluation and licensing process. Traditionally the conservative approach opted for the point kinetics model, expressing the reactor core parameters in the form of reactivity and power tables. However, with the current advances in computational power, high fidelity multi-physics simulations using real-time code coupling, can provide more detailed core behavior and hence more realistic plant's response. This is particularly relevant for transients where the core is undergoing reactivity anomalies and uneven power distributions with strong feedback mechanisms, such as reactivity initiated accidents (RIAs). This work addresses a RIA, specifically a control element assembly (CEA) withdrawal at power, using the multi-physics analysis tool RELAP5/MOD 3.4/3DKIN. The thermal-hydraulics (TH) code, RELAP5, is internally coupled with the nodal kinetics (NK) code, 3DKIN, and both codes exchange relevant data to model the nuclear power plant (NPP) response as the CEA is withdrawn from the core. The coupled model is more representative of the complex interactions between the thermal-hydraulics and neutronics; therefore the results obtained using a multi-physics simulation provide a larger safety margin and hence more operational flexibility compared to those of the point kinetics model reported in the safety analysis report for APR1400. The systems engineering approach is used to guide the development of the work ensuring a systematic and more efficient execution.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.689-691
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• 2002

Well-aligned multi-wall carbon nanotubes (MWCNTs) have been grown on both Coming glass and silicon substrates at about 400 $^{\circ}C$ by a modified plasma - enhanced chemical vapor deposition system. We have investigated laser irradiation effect on carbon nanotube surface by using an ultra - violet laser. The laser operated to modify structural defect of was carbon nanotube and to ablate possible contamination of carbon nanotube surface. The morphology and surface transformation of MWCNTs as analyzed by a SEM. In addition, the field emission measurement was also carried out in a vacuum chamber with a $10^{-7}$ Torr base pressure by applying bias voltages up to 1000V.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.692-693
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• 2002

Well-aligned multi-wall carbon nanotubes (MWNTs) were fabricated by utilizing a radio frequency plasma-enhanced chemical vapor deposition (rf-PECVD) system from Ni particles at the bottom of anodic alumina nanoholes (AAN). To remove the amorphous graphite layers on the AAN surface and to eliminate the protrusion of MWNT tips, the AAN surface with MWNTs were treated by external rf plasma source. As a result, the AAN surface almost became flat without having any protrusion of MWNT tips. The diameter, length of MWNTs and AAN were investigated by using a scanning electron microscopy (SEM). Raman spectroscopy was also used to characterize wall structure of the carbon nanotube. And the emission properties of the MWNTs were measured for the application of field emission display (FED) in near future.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.2
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• pp.67-70
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• 2002

Multi-period low-emissivity (low-e) filters based on [TiO$_2$｜Ti｜Ag｜TiO$_2$] layer structure were designed and fabricated by a RF magnetron sputtering method. Optical, structural, chemical, and electrical properties were investigated with various analytical tools. Interface layers consisting of Ag, Ti, and O were observed next to Ag layers by Rutherford backscattering spectrometry (RBS) analysis. The results show that Ti layers of ~ 1.8 nm protect the Ag layers from oxidation better than those of ~ 1 nm and the optical spectra of the filter with thicker Ti layers are in agreement with the simulated one. The average transmittance of a low-e filter with thicker Ti layers is reduced and the sheet resistance is slightly increased due to the increased Ti thickness.