• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.337-342
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• 2015

The company of 4 core materials that are needed for photovoltaic generation is located in area around this university in Gunsan, Saemangeum. And also, it was almost completed the value chain about the production of Polysilicon, Ingot, Wafer, modules and the design, construction of generation system. The industry-academy-government has understood that because of the relative companies' production and investment, it leads to a supply and demand of manpower and thus will have field centered manpower education. This program will help the problem of lack of manpower in relative companies by establishing competitive major agreement like vocational education system. Also, the university and the participating company in joint have pushed ahead field business education to make the least of industrial-education's mismatch, the training of professional manpower connected with related industries to make the universities chemical characteristics, companies securing excellent manpower and contributed to the revitalization of the regional economy. In this paper, are aware that photovoltaic industry is a future strategic industry for the country, so we will train the immediately site adapting manpower for the area of photovoltaic material and system as our goal. This is shown results of education operation for 4 years.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.111.1-111.1
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• 2011

The solar energy is dramatically increasing as the alternative energy source and the silicon(Si) solar cell are used the most. In this study, the improved process and equipment for the metallurgical refinement of multicrystalline Si were evaluated for the inexpensive solar cell. The planar plane and columnar dendrite aheadof the liquid-solid interface position caused the superior segregation of impurities from the Si. The solidification rate and thermal gradient determined the shape of dendrite in solidified Si matrix solidified by the directional solidification(DS) method. To simulate this equipment, the commercial software, PROCAST, was used to solve the solidification rate and thermal gradient. Si was vertically solidified by the DS system with Stober process and up-graded metallurgical grade or metallurgical grade Si was used as the feedstock. The inductively coupled plasma mass spectrometry (ICP) was used to measure the concentration of impurities in the refined Si ingot. According to the result of ICP and simulation, the high thermal gradient between the two phases wasable to increase the solidification rate under the identical level of refinement. Also, the separating heating zone equipped with the melting and solidification zone was effective to maintain the high thermal gradient during the solidification.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.130-139
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• 2004

The cladding materials remaining after reprocessing process of the nuclear fuel, generally called as hulls, are classified as a high-level radioactive waste. They are usually packaged in the container for disposal after being compacted, melted, or solidified into the matrix. The efforts to fabricate a better ingot for a more favorable disposal to the environment have failed due to the technical difficulties encountered in the chemical decontamination method. In the early 1990s, the accumulation of radio-chemical data on hulls and the advent of new technology such as a laser or plasma have made the pre-treatment of the hulls more efficient. This paper summarizes the information regarding the radio-chemical analysis of the hull through a literature survey and determines the characteristics of the hull and depth profile of the radio-nuclides within the hull thickness. The feasibility study was carried out to evaluate the reduction of the radioactivity by peeling off the surface of the hull with the application of laser technology.

• Journal of Korea Foundry Society
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• v.21 no.2
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• pp.119-126
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• 2001

Al/15%Gr. composite have been manufactured by mixing, compacting, and extruding aluminium powder and graphite powder. Then, Al-6%Si/x%Gr., Al-12%Si/x%Gr., and Al-18%Si/x%Gr.(x: 0, 2, 4, 6, 8) composites have been manufactured by remelting the extruded materials(Al/15%Gr.), Al-33.3%Si alloy, and Al ingot, etc. We conducted experiments to chracterize the microstructure, and damping properties and hardness. The result of microstructure experiment on Al-x%Si/y%Gr. composites reveals the good dispersion of graphite. As to Al-Si/y%Gr. composites, the more the graphite contents, the less the tensile strength. And the tensile strength varied according to contents of Si: with its highest value in Al-18%Si/y%Gr. composites and lowest in Al-6%Si/y%Gr. composites. As to Al-x%Si/y%Gr. composites, the more the contents of graphite, the more the vibration damping properties. And we can get the highest vibration damping rate in Al-12%Si/y%Gr. composites which matrix structure is an eutectic component.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.232-232
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• 2006

SiC single crystal Ingots were prepared onto different seed material using sublimation PVT techniques and then their crystal quality was systematically compared. In this study, the conventional SiC seed material and the new SiC seed material with an inserted SiC epitaxial layer on a seed surface were used as a seed for SiC bulk growth. The inserted epitaxial layer was grown by a sublimation epitaxy method called the CST with a low growth rate of $2{\mu}m/h$ N-type 2"-SIC single crystals exhibiting the polytype of 6H-SiC were successfully fabricated and carrier concentration levels of below $10^{17}/cm^3$ were determined from the absorption spectrum and Hall measurements. The slightly higher growth rate and carrier concentration were obtained in SiC single crystal Ingot grown on new SiC Seed materials with the inserted epitaxial layer on the seed surface, maintaining the high quality.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.516-521
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• 2002

A study was carried out to grow an understanding of the microstructural development of friction stir welds on an AZ91D magnesium alloy, and to evaluate the mechanical properties of the welds. AZ91D plates with the thickness of 4mm were used, and the microstructural development of the weld zone was investigated using optical and scanning electron microscopes. Square butt welding joint with good quality was obtained at the conditions of under 187mm/min of travel speed with 1100 to 1250 rpm of tool rotation speed. The microstructure within the weld region consisted of fine equiaxed grains with no evidence of the original dendritic structure. The hardness tests showed slightly increased harness in the weld region, and the minimum hardness measured is in that of the parent material. Tensile strength of the weld zone was remarkably improved due to very fine recrystallized structure. XRD pattern of weld zone revealed the removal of $\beta$ intermetallic compounds, $Mg_{17}$Al$_{12}$, which had been distributed in the base metal.l.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.139-145
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• 1989

An eutectic melt in the system(Bi2O3)0.85·(Nb2O5)0.15-6Bi2O3·SiO2 was unidirectionally solidfield at a rate of 0.5mm/h under a thermal gradient of 100℃/cm. Double crucibles and seed crystal plate were used in order to botain the composite crystals which had uniform microstructure throughout the ingot. The obtained composite crystals showed uniform microstructure, in which needle-like δ-(Bi2O3)0.85·(Nb2O5)0.15 crystals were arrayed in parallel in a matrix of γ-6Bi2O3·SiO2 single crystal. It was found that the <110> direction of δ-(Bi2O3)0.85·(Nb2O5)0.15 crystal was essentially parallel to the <111> direction of γ-6Bi2O3·SiO2 crystal in the composite crystals. A transverse thin plate of the composite crystals showed a high resolution optical transmission like an optical fiber array, and sharp chatoyancy was observed in the cabochon shaped composite crystals. Then, this may be useful for applications such as screen of a cathode ray tube or artificial cat's eye gem stones.

• Journal of Korea Foundry Society
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• v.18 no.3
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• pp.283-288
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• 1998

Interest in rapid solidification of magnesium alloys stems from the fact that conventional ingot metallurgy alloys exhibit poor strength, ductility, and corrosion resistance. Such properties can be improved by microstructural refinement via rapid solidification processing. In this study, Mg-Zn alloys have been produced as continuous strips by melt overflow technique. In order to evaluate the influence of additional elements on the grain refinement and mechanical properties, Th and Zr were added in rapidly solidified Mg-5wt%Zn alloy. Then the microstructual observations were undertaken with the objective of evaluating the grain refinement as function of the cooling rate and the additional elements. The tremendous increase in hardness of Mg-Zn base alloys was mainly due to the refinement of the grain structure by the effect of rapid solidification and alloying elements. The formation of intermetallic phases on the grain boundaries may have a positive effect on the corroion resistance. Therefore, despite competition from many other developments, the rapid solidification processing of magnesium alloys emerges as a valuable method to develop superior and commercially acceptable magnesium alloys.

• Journal of Korea Foundry Society
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• v.31 no.6
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• pp.336-341
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• 2011

Recently, aluminium usage in the automobile industry has been increased cause of its lightweight. The aluminium has a melting-solidification process in producing line and another melting process was needed in manufacturing process. Two times of melting process for making ingot and casting not only makes the loss of time and money but contaminates the air with Sox, Nox. For this reason, the holding furnace with laminated adiabatic material was developed. This holding furnace can deliver the molten aluminium directly to the industry needing molten aluminium. Recent holding furnace has above $15^{\circ}C/h$ of cooling rate and that causes solidification of molten aluminium. The ANSYS software was used to analysis the heat transfer. The adiabatic materials were laminated with optimized arrangement and holding furnace shape was changed with optimized modelling by ANSYS analysis for reducing the cooling rate of molten aluminium in holding furnace.

• Journal of Power System Engineering
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• v.20 no.6
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• pp.58-63
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• 2016

A stainless steel has high corrosion resistance because of nickel in material, so it is used as materials for transportation and storage of hydrogen. In this study, TIG(tungsten ingot gas) welding was carried out on the stainless steel using the storage vessel of hydrogen. The microscopic structures at each region of TIG welded material such as HAZ, weld and base metals using optical microscope were observed. And the damage behavior of stainless steel that underwent the hydrogen charging using nondestructive evaluation was also studied. Ultrasonic test, which is the most generalized nondestructive technique, was applied to evaluate the relationship between the ultrasonic wave and mechanical properties at each zone of TIG welded stainless steel. The velocity and attenuation coefficients of ultrasonic wave didn't show a remarkable difference at each region of welded stainless steel. However, the attenuation coefficient was the highest at the weld zone when hydrogen charged stainless steel. In addition, acoustic emission test was also used to study the dynamic behavior of stainless steel experienced both hydrogen charging and weld. Lots of AE event at elastic region of stress-strain curve were occurred both the hydrogen charged specimen and the free specimen.