• Journal of Welding and Joining
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• v.31 no.1
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• pp.58-64
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• 2013

The following results were obtained, microstructures and tensile properties in arc brazed joints of DP(dual phase) steel using Cu-5.3wt%Sn insert metal was investigated as function of brazing current. 1) The Fusion Zone was composed of ${\alpha}Fe+{\gamma}Cu$ and Cu23Sn2. The reason for the formation of these solid solutions. Despite, Fe & Cu were impossible to solid solution at room temperature. It's melting & reaction to something of insert metal & Base Metal (DP Steel) by Arc. Brazing Process has faster cooling rate then Cast Process, Supersaturated solid solution at room temperature. 2) The increase Hardness of Fusion Zone was directly proportional to the rise of welding current. Because, ${\alpha}Fe+{\gamma}Cu$ phase (higher hardness than the Cu23Sn2.(104.1Hv < 271.9Hv)) Volume fraction was Growth, due to increasing the amount of base metal melting by High current. 3) The results of tensile shear test by Brazing, All specimens happen to fracture in Fusion Zone. On the other hand, when Brazing Current increasing tend to rise tensile load. but it was very small, about 26-30% of the base metal. 4) The result of fracture analysis, The crack initiate at Triple Point for meet to Upper B.M/Under B.M/Fusion Zone. This Crack propagated to Fusion zone. So ruptured by tensile strength. The Reason to in the fusion zone fracture, Fusion zone by Brazing of hardness (strength) was very lower then the base metal (DP steel). In addition the Fusion Zone's thickness in triple point was thin than the base metal's thickness in triple point.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.41-48
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• 2015

Coffee consumption in Korea has been currently growing every year, and as a result, approximately 0.2 million tons of Spent Coffee Grounds (SCG) are being created every year. SCG, which is waste organic material, is often classified as food waste and an annual amount of 0.27 million ton is discarded while containing moisture and provoking serious environmental issue. Physico-chemical characteristics of SCG were analyzed in this study and medium and long-term growth experiments were conducted in order to evaluate its utilization potential. According to the experiment results, mixing SCG into the previous base material resulted in accelerated germination and growth in the mid-term compared to previous base material alone, despite slower germination or growth in early stage. Especially, it showed lower withering rate and decrease in various symptoms that are caused by nutrition shortage in case of discontinued sprinkling, etc., compared to the previous base material. Hence, while SCG has a feature of hindering early development due to its feature of waste organic material that is rich in nitrogen, its benefit for long-term growth coming its moisturizing ability and supply of organic matter was confirmed in the study. On balance, SCG is believed to be a material that can replace or complement the previous base materials.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.101-106
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• 1997

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.515-522
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• 1993

The purpose of this study was to evaluate the bond strength of rebase resin to denture base resin. The denture base resins in this study were Premium Super-20(Lang Dental Mfg. Co. Inc., Wheeling, USA) and Lucitone 199(Dentsply International Inc., York, USA). And the rebase resins were Repair Acrylic(Lang Dental Mfg. Co. Inc., Wheeling USA). Toughron Rebase(Miki Chemical Product Co. Ltd., Japan) , Tokuso Rebase(Tokuyama Soda. Co. Ltd., Japan) and Triad VLC Reline Material(Dentsply International Inc., York, USA). The obtained results were as follows : 1. The bond strength of Repair Acrylic to Premium Super-20, and that of Toughron Rebase to Lucitone 199 were the highest. 2. In Premium Super-20 and Lucitone 199, bond strength of all rebase resins had significant differences. 3. The bond strength of Triad VLC Reline Material was inclined to the lowset.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.318-321
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• 2002

This paper presents a proper condition to achieve high conversion efficiency using PC1D simulator on sri-crystalline Si solar cells. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer, BSF thickness and doping concentration were investigated. Optimized cell parameters were given as rear surface recombination of 1000 cm/s, minority carrier diffusion length in the base region 200 $\mu\textrm{m}$, front surface recombination velocity 100 cm/s, sheet resistivity of emitter layer 100 Ω/$\square$, BSF thickness 5 $\mu\textrm{m}$, doping concentration 5${\times}$10$\^$19/ cm$\^$-3/. Among the investigated variables, we learn that a diffusion length of base layer acts as a key factor to achieve conversion efficiency higher than 19 %.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.799-805
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• 2004

Two dimensional MEDICI simulator is used to study the characteristics of latch-up current of Dual Gate Emitter Switched Thyristor. The simulation is done in terms of the current-voltage characteristics, latch-up current density, ON-voltage drop and electrical property with the variations of p-base impurity concentrations. Compared with the other power devices such as MOS Controlled Cascade Thyristor(MCCT), Conventional Emitter Switched Thyristor(C-EST) and Dual Channel Emitter Switched Thyristor(DC-EST), Dual Gate Emitter Switched Thyristor(DG-EST) shows to have the better electrical characteristics, which is the high latch-up current density and low forward voltage-drop. The proposed DG-EST which has a non-planer p-base structure under the floating $N^+$ emitter indicates to have the better characteristics of latch-up current and breakover voltage.

• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.60-65
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• 2014

Teeth that have short clinical crown, which are not alone enough to support the definitive restoration can be best treated using the post and core system. The advantages of fiber post over conventional metallic post materials have led to its wide acceptance. In addition to that the combination of aesthetic and mechanical benefits of fiber post has provided it with a rise in the field of dentistry. Also the results obtained from some clinical trials have encouraged the clinicians to use the fiber posts confidently. Fiber posts are manufactured from pre-stretched fibers impregnated within a resin matrix. The fibers could that be of carbon, glass/silica, and quartz, whereas Epoxy and bis-GMA are the most widely used resin bases. But recently studies are also found to be going on for polyimide as possible material for the fiber post resin base as a substitute for the conventional materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.149-153
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• 2003

In URD(Underground Residential Distribution) power cable, experiments of WVT(Water Vapor Transmission) test on the Base Resin accomplished to specimens which contained CB(Carbon Black), anti-oxidant to base resin and made by pressing to resin of pellet or lump form. a kind of specimens was HDPE(High Density Polyethylene), MDPE(Medium Density Polyethylene), LDPE(Low Density Polyethylene), LLDPE(Linear Low Density Polyethylene), PVC(Polyvinyl Chloride). as a results of WVT test, we saw that WVT ratio was HDPE < LLDPE < MDPE≒LDPE${\ll}$ PVC. WVT properties of PVC using for jacket showed properties 15-20 times more than MDPE or LLDPE. Therefore, to development of watertightness cable, our works present need of Changing in insulating materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.21-25
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• 1999

In order to remove minority carries of the base region at changing signal in conventional bipolar logic circuit, we made transistor which is composed of NPN transistor shortened buried layer under the Base region, PNP transistor which is merged in base, epi layer and substrate. Also the Ring-Oscillator for measuring transmission time-delay per gate was designed as well. In the result, we get amplitude of logic voltage of 200mV, the minimum of transmission delay-time of 211nS, and the minimum of transmission delay-time per gate of 7.26ns in AC characteristic output of Ring-Oscillator connected Gate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.794-798
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• 2011

This paper was carried out design of 1,700 V Base Resistance Thyristor for fabrication. We decided conventional BRT (base resistance thyristor) device and Trench Gate type one for design. we carried out device and process simulation with T-CAD tools. and then, we have extracted optimal device and process parameters for fabrication. we have analysis electrical characteristics after simulations. As results, we obtained 2,000 V breakdown voltage and 3.0 V Vce,sat. At the same time, we carried out field ring simulation for obtaining high voltage.