• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.535-540
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• 1997

Potassium carbonate reacts with silicon tetrachloride to form trichlorosilyloxy carbonylchloride which reacts subsequently with another molecule of silicon tetrachloride leading to phosgene eventually in chlorinated solvents. This in situ generated trichlorosilyloxy carbonylchloride or phosgene were found to be very effective for the chlorination of a wide variety of alcohols to the corresponding chlorides. Primary, secondary and benzylic alcohols were converted into corresponding chlorides when treated with silicon tetrachloride in the presence of potassium carbonate at room temperature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.06a
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• pp.160-173
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• 1997

Microstructure of hypereutectic Al-17wt.% Si alloy, fabricated by mechanical stirring and by reheating at semi-solid state, was investigated by optical microscope. Flow behavior semi-solid metal also was investigated at diffentent mould temperatures 280$^{\circ}C$, 290$^{\circ}C$ and 300$^{\circ}C$. Size of silicon particles were increased over 100$\mu\textrm{m}$ during solidification as a result of stirring. It is considered as microstructural coarsening by bonding between neighbouring primary silion particles during stirring of slurry. In case of reheating at semi-solid state, however, primary silicon particle was not increased at size of 40$\mu\textrm{m}$ and nearly spherical aluminum solde particle also could be obtained uniformly in distribution. The fludity of Al-17wt.% Si alloys at semi-solid state was improved when solid fraction was 0.7 at mould temperature of 300$^{\circ}C$ than other conditions.

• Journal of Korea Foundry Society
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• v.6 no.2
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• pp.116-121
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• 1986

The effects of pressure during solidification on macro-and micro-structures have been studied in pure aluminium and Al-Si alloys. The application of pressure during solidifcation accelerated both equiaxed and columnar dendritic-growth due to stimulating of equiaxed survival and faster preferential growth of primary dendrites against the parallel direction of heat flow. Burden-Hunt model was modified to express the significant changes of CET behaviours under pressure. A further point to be noted was that greatly fine eutectic silicon flakes ($0.5\;{\times}\;13{\mu}m$) with the decrease of halo layers ($7{\mu}m$) of aluminium riched phases in the periphery of primary silicon particles were observed when pressure was applied during solidification.

• Korean Journal of Materials Research
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• v.15 no.7
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• pp.480-485
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• 2005

Sc has been known to be an very effective ppt-hardening element in Al and Al alloys and also to be effective in modification of eutectic Si in hypoeutectic Al-Si alloys. The modification mechanism of Sc is different from that of the traditional modifier Sr in Al-Si alloys. In the present study the effects of Sc on the primary and eutectic Si in hypereutectic Al-Si alloys were investigated with evaluating the microstructures with OM, EPMA and EBSD methods. The results represent that Sc has only a small effect on primary Si when added less than $0.8wt\%$. However, when Sc addition leading to the precipitation of metallic Sc within primary Si reaches $1.6wt\%$, very coarse primary Si occurs.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.346-347
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• 2011

본 논문에서는 정전류 LED조명 구동을 위한 일차측 전류 제어의 새로운 기법을 제안한다. 일정한 온-타임으로 동작하는 경계 모드(Critical Mode) 플라이백 타입으로 우수한 역률을 달성하였고, 의사 공진(Quasi-resonant) 동작으로 스위칭 손실을 최소화 하였다. 본문에서 LED전류가 5% 이하로 정전류 제어되는 9W급 플라이백 타입의 일차 측 전류 제어 기법을 실험으로 검증한다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1352-1355
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• 2004

We have applied front contact metallization of plated nickel and copper for high efficiency passivated emitter rear contact(PERC) solar cell. Ni is shown to be a suitable barrier to Cu diffusion as well as desirable contact metal to silicon. The plating technique is a preferred method for commercial solar cell fabrication because it is a room temperature process with high growth rates and good morphology. In this system, the electroless plated Ni is utilized as the contact to silicon and the plated Cu serves as the primary conductor layer instead of traditional solution that are based on Ti/Pd/Ag contact system. Experimental results are shown for over 20 % PERC cells with the Plated Ni/Cu contact system for good performance at low cost.

• Journal of Korea Foundry Society
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• v.26 no.6
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• pp.241-248
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• 2006

The effects of silicon content and melt treatment on the fluidity of Al-Si alloys during squeeze casting were investigated. The fluidity of Al-3.0 wt%Si alloy was found to be lower than that of Al-1.0 wt%Si and the fluidity of the alloy with more than 3.0 wt%Si increased with the silicon content upto 13.0 wt% and rather decreased with15.0 wt%. The fluidity was also increased by the separated treatment of grain refinement or eutectic modification, and even more by the simultaneous treatment of both. The fluidity of hypereutectic alloy was increased by the refinement of primary silicon particle.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.6-11
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• 2015

The ESD(electrostatic discharge) protection performance of PPS(PMOS pass structure) embedded N-type silicon controlled rectifier(NSCR_PPS) device with different GPNS(Gate to Primary $N^+$ Diffusion Space) structure was discussed for high voltage I/O applications. A conventional NSCR_PPS standard device with FPW(Full P-Well) structure and non-CPS(Counter Pocket Source) implant shows typical SCR-like characteristics with low on-resistance(Ron), low snapback holding voltage(Vh) and low thermal breakdown voltage(Vtb), which may cause latch-up problem during normal operation. However, our proposed NSCR_PPS devices with modified PPW(Partial P-Well) structure and optimal CPS implant demonstrate the improved ESD protection performance as a function of GPNS variation. GPNS was a important parameter, which is satisfied design window of ESD protection device.

• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.541-546
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• 1997

Manganese dioxide may react with silicon tetrachloride to form manganese(Ⅳ) oxodichloride which reacts subsequently with another molecule of silicon tetrachloride leading to manganese tetrachloride eventually in chlorinated solvents. This in situ generated manganese(Ⅳ) oxodichloride or manganese tetrachloride were found to be very effective for the chlorination of a wide variety of alcohols to the corresponding chlorides. Primary, secondary and benzylic alcohols were converted into corresponding chlorides when treated with silicon tetrachloride in the presence of manganese dioxide at room temperature.

• Current Photovoltaic Research
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• v.12 no.1
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• pp.6-16
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• 2024

The efficiency of silicon solar cells is approaching a theoretical limit referred to as 'the state of the art'. Consequently, maintaining efficiency is more productive than pursuing improvements the last room for limiting efficiency. One of the primary considerations in silicon module conservation is the occurrence of failures and degradation. Degradation can be mitigated during the cell manufacturing stage, unlike physical and spontaneous failure. It is mostly because the chemical reaction is triggered by the carrier generation of thermal and light injection, an inherent aspect of the solar cell environment. Therefore, numerous researchers and cell manufacturers are engaged in implementing mitigation strategies based on the physical degradation mechanism.