• Journal of the Korean institute of surface engineering
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• v.26 no.6
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• pp.307-315
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• 1993

A study on a new anti-finger printed EGI steel sheet with high corrosion resistance has been carried out to meet the recent requirement of high quality and performance of the pure zinc electrogalvanized steel sheet. The substrate was the pure zinc electrogalvanized sheet with the metallic coating of 20g/$\m^2$. The two differ-ent processes for inorganic(chromating) and organic(resin) coating were applied. One was a two coat/two bake type to separately treat chromating and resin coating which is now widely used. The other was a one coat/one bake type to simultaneously treat them which is newly developed in this study. The solution for the one coat/one bake type was an aqua-base coating agents which was composed of inorganic and organic components. The new anti-finger printed EGI steel sheet with the Cr and resin coating weight of 13mg/$\m^2$ and 800mg/$\m^2$, respectively shows the superior corrosion resistance besides the good paintability, formability fingerprint resistance and earth characteristics properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.282-282
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• 2010

결정질 태양전지는 상대적으로 고효율이 보장되며, 낮은 공정 비용 등의 이유로 널리 사용되고 있는 기술이다. 결정질 태양전지의 효율을 증가시키는 공정 방법에는 표면 구조화, 도핑 농도, 반사방지막, 금속전극 형성 등이 있다. 특히, 도핑 공정에서 도핑 농도를 변화시킬 수 있으며, 이에 의하여 면 저항값을 변화 시킬 수 있다. 본 연구에서는 결정질 태양 전지에서 도핑 농도의 조절에 의한 이상적인 sheet resistance를 얻기 위한 실험을 진행하였다. 3개의 실험 set을 두고 각각의 경우를 실험하였다. 본 연구에서는 Pre-deposition과 drive-in 방법을 사용한 doping의 2가지 step으로 실험을 진행하였다. pre-deposition의 시간 condition은 21분으로 하였다. $N_2$ 분위기에서 $O_2$와 $POCl_3$ 의 비율을 각각 100sccm, 200sccm으로 하여 실험을 진행하였다. 변수인 온도의 경우는 각각의 set에 대하여, $830^{\circ}C$, $840^{\circ}C$, $850^{\circ}C$ 로 가변하였다. pre-deposition을 끝낸 뒤, sheet resistance의 값은 각각 $75{\sim}90\;\Omega/square$, $68{\sim}75\;\Omega/square$, $56{\sim}63\;\Omega/square$의 값을 나타내었다. 도핑의 경우에는 drive-in 방법을 사용하였으며, 모든 경우에서 20분에서 $890^{\circ}C$에서 진행하였다. 최종 sheet resistance의 값은 각각의 경우 최대 $33\;\Omega/square$, $34\;\Omega/square$, $30\;\Omega/square$의 값을 나타내었다. $40{\sim}45\;\Omega/square$ 정도의 sheet resistance가 많은 연구에서 이상적인 sheet resistance로 연구되고 있다. 본 연구에서 두 번째 조건이 이상적인 sheet resistance에 가장 접근 하였음을 확인 할 수 있다.

• Journal of Welding and Joining
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• v.26 no.5
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• pp.79-89
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• 2008

With the increased use of surface textured steel sheet in body-in-white assembly, resistance spot weldability of these steels is considered to be an important subject. This study evaluated nugget formation and weldability by measuring dynamic resistance with various weld pressure, current, and weld time for steel sheet with two different surface roughnesses. The surface roughness for T-H steel ($R_{a}=1.70\;{\mu}m$) was higher than that for T-L steel ($R_{a}=1.33\;{\mu}m$), and resulted in increased contact resistance and heating for T-H steel spot welding. Therefore, at low weld current and weld cycle ranges, the T-H steel showed better weldability over the T-L steel. The evaluations of weld interface showed that the fusion zone in the T-H steel sheet was continuous in contrast to discontinuous fusion zone for T-L steel sheet at the same welding conditions. A comparison of dynamic resistance and tensile-shear strength (TSS) between T-H and T-L steel sheet suggested that high surface roughness provided larger heating at early cycle of welding and larger TSS.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.5
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• pp.36-41
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• 2008

Multi-ply sheet forming has many advantages including the possibility of using wide range of materials in a given structure, lowering production cost, making higher grammage products and so on. But, incorrect structure of sheet makes flow resistance higher so that it shows poor dewatering in press section. One of major factors that affect sheet structure and dewatering property is fines content in each layer. We, therefore, examined the press dewatering of multi-ply sheet that has the different fines content in each layer and the effect of fines distribution on physical properties of sheet to find a technology for optimum utilization of raw materials. In case of two layered sheet, the sheet which was composed of layers with the different flow resistance showed higher dewatering rate than one which has the same flow resistance. And the more difference in fines content for layers existed, the more dewatering occurred. For three layered sheets, dewatering is mainly dependent on fines content of bottom layer. Strength properties were affected by dewatering degree and multi-ply sheet structure.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.59-65
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• 2016

PURPOSES : This paper aims to develop a road pavement de-icing system using carbon sheet to replace the older snow de-icing method. Carbon sheet is a light and high-strength metal. Hence, various bodies of research for its applications in many industries have progressed. METHODS : The experiment was conducted in a laboratory. The carbon sheet supplied voltage through a power supply system, and produced heat transfers to the concrete surface. Various factors, such as pavement material, carbon sheet width, penetration depth, and freezing-thawing resistance, were considered in the conducted experiments to confirm the heating transfer efficiency of the carbon sheet. RESULTS : The carbon sheet used was a conductor. Therefore, it produced heat if voltage was supplied. The exposed carbon sheet on the atmosphere did not affect the carbon sheet width when it provided constant voltage. However, the sheet showed different heating behaviors by width change when the carbon sheet penetrated into the concrete. Moreover, the freezing-thawing resistance was decreased by the carbon sheet with increasing width. CONCLUSIONS : The experiments confirmed the possibility of developing a road snow melting system using a carbon sheet. The antiicing system using the carbon sheet to replace the traditional anti-icing system has disadvantages of environmental pollution risk and electric leakage. The pavement also improved its toughness resistance. The utilization value will be very high in the future if carbon sheet heat loss can be minimized and durability is improved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.938-942
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• 2008

Electrical and optical properties of semitransparent Ag and Al layer were studied, which are used for the electrodes in top-emission organic light-emitting diodes. Sheet resistance and transmittance of visible light through a thin layer were measured and analyzed. Several thin metal layers of Ag and Al were deposited onto a glass substrate up to a thickness of 50 nm using a thermal evaporation. Sheet resistance measurements show that a layer thickness is needed more than 15 nm and 20 nm for Ag and Al, respectively, when a proper sheet resistance is assumed to be less than $50{\Omega}/sq$. From the measurements of transmittance of visible light through a thin-metal layer, metallic behavior was observed when the layer thickness is over 25 nm for both films. Thus, from a study of sheet resistance and transmittance of visible light, a minimum proper thickness of semitransparent metal layer is 20 nm and 25 nm for Ag and Al, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.188-188
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• 2010

동일한 에너지와 일정한 dose량을 유지하고 dose rate만을 변화시켜가며 이온을 Si(100) 표면에 주입하였다. 이러한 조건하에서 이온의 dose rate가 커지게 되면 시료 내에서 relaxation되는 시간이 짧아져서 damage의 양이 증가하게 되고 depth profile의 꼬리부분이 표면 쪽으로 올라오게 된다. 이와 같은 damage profile의 변화가 sheet resistance에 영향을 준다는 실험결과가 있다. 본 연구에서는 Crystal-TRIM computer simulation을 통해서 depth profile과 damage profile의 결과를 얻고, dose rate가 커질수록 시료표면 근방에 잔류 damage의 양이 높게 나타나는 것을 확인할 수 있다. 또한, 잔류 damage의 표면근방에서의 분포가 annealing 이후 sheet resistance를 변화시키는데 이에 대한 mechanism을 규명하고자 한다.

• Korean Journal of Materials Research
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• v.12 no.11
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• pp.883-888
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• 2002

We investigated the void formation in composite-titanium silicide($TiSi_2$) process. We varied the process conditions of polycrystalline/amorphous silicon substrate, composite $TiSi_2$ deposition temperature, and silicidation annealing temperature. We report that the main reason for void formation is the mass transport flux discrepancy of amorphous silicon substrate and titanium in composite layer. Sheet resistance in composite $TiSi_2$ without patterns is mainly affected by silicidation rapid thermal annealing (RTA) temperature. In addition, sheet resistance does not depend on the void defect density. Sheet resistance with sub-0.5 $\mu\textrm{m}$ patterns increase abnormally above $850^{\circ}C$ due to agglomeration. Our results imply that $sub-750^{\circ}C$ annealing is appropriate for sub 0.5 $\mu\textrm{m}$ composite X$sub-750_2$ process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.173-178
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• 2008

This is green roof bottom system which composed by aluminum valve and glass fiber together as major reinforcement, so the cooper sheet can have root proof, and using recycled tire gel-type membrane waterproofing system which dost not contains VOCs. The copper sheet reduce the plants' root growing, so it helpes to maintain the waterproofing layer and stability of root proofing. Gel type membrane waterproofing system can do waterproofing, stress dispersion, and reducing leakage expansion. So those two materials can help each other to make green roof bottom layer would have the stability and durability.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1069-1072
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• 2003

Germane-sillicide phase formation on S $i_{0.25}$G $e_{0.75}$ with Ni 100$\square$, Co 10$\square$/Ni 100$\square$ and Ni 50$\square$/Co 10$\square$/Ni 50$\square$ layer was studied by sheet resistance and Field Emission Scanning Electron Microscopy(FESEM). Thermal stability of nickel germane-silicide is found to be improved by sputtering Ni/Co/Ni on the SiGe. After annealing at 600, 650, $700^{\circ}C$, 30min., the nickel germane-silicide formed by Ni 50$\square$/Co 10$\square$/Ni 50$\square$ layer achieved a sheet resistance less than 17ohms/sq.(almost the same to the value before furnace annealing for 30min.) , while the process of the other two ways result in high sheet resistance and even sheet resistance fail due to Ge segregation.ion.