• Title, Summary, Keyword: selective removal

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Effects of Laser Doping on Selective Emitter Si Solar Cells (레이져를 이용한 도핑 특성과 선택적 도핑 에미터 실리콘 태양전지의 제작)

  • Park, Sungeun;Park, Hyomin;Nam, Junggyu;Yang, JungYup;Lee, Dongho;Min, Byoung Koun;Kim, Kyung Nam;Park, Se Jin;Lee, Hae-Seok;Kim, Donghwan;Kang, Yoonmook;Kim, Dongseop
    • Current Photovoltaic Research
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    • v.4 no.2
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    • pp.54-58
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    • 2016
  • Laser-doped selective emitter process requires dopant source deposition, spin-on-glass, and is able to form selective emitter through SiNx layer by laser irradiation on desired locations. However, after laser doping process, the remaining dopant layer needs to be washed out. Laser-induced melting of pre-deposited impurity doping is a precise selective doping method minimizing addition of process steps. In this study, we introduce a novel scheme for fabricating highly efficient selective emitter solar cell by laser doping. During this process, laser induced damage induces front contact destabilization due to the hindrance of silver nucleation even though laser doping has a potential of commercialization with simple process concept. When the laser induced damage is effectively removed using solution etch back process, the disadvantage of laser doping was effectively removed. The devices fabricated using laser doping scheme power conversion efficiency was significantly improved about 1% abs. after removal the laser damages.

Nitrogen Oxides Removal Characteristics of SNCR-SCR Hybrid System (SNCR-SCR 하이브리드 시스템의 질소산화물 제거 특성)

  • Cha, Jin Sun;Park, Sung Hoon;Jeon, Jong-Ki;Park, Young-Kwon
    • Applied Chemistry for Engineering
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    • v.22 no.6
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    • pp.658-663
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    • 2011
  • The SNCR-SCR (selective non-catalytic reduction-selective catalytic reduction) hybrid system is an economical NOx removal system. In this study, the effect of the operating parameters of the SNCR-SCR hybrid system on NOx removal efficiency was investigated. When the SNCR reactor was operated at a temperature lower than the optimum temperature ($900{\sim}950^{\circ}C$), an additional NO removal is obtained basesd on the utilization of $NH_3$ slip. On the other hand, the SNCR reactor operated above the temperature resulted in no additional NO removal of SCR due to decomposition of $NH_3$. Therefore, the SNCR process should be operated at optimum temperature to obtain high NO removal efficiency and low $NH_3$ slip. Thus, it is important to adjust NSR (normalized stoichiometric ratio) so that $SR_{RES}$ can be maintained at an appropriate level.

Desalting of papermaking tobacco sheet extract using selective electrodialysis

  • Li, Chuanrun;Ge, Shaolin;Li, Wei;Zhang, Zhao;She, Shike;Huang, Lan;Wang, Yaoming
    • Membrane Water Treatment
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    • v.8 no.4
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    • pp.381-393
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    • 2017
  • The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.

Separation of Radiostrontium from Environmental Sample Using Strontim Selective Chromatographic Resin$(Sr.\;Spec^{TM})$ (스트론튬 선택적이온교환수지$(Sr.\;Spec^{TM})$를 이용한 환경시료중의 방사성 스트론튬의 분리)

  • Hong, Kwang-Hee;Lee, Chang-Woo;Choi, Yong-Ho;Lee, Myung-Ho
    • Journal of Radiation Protection and Research
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    • v.20 no.1
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    • pp.1-7
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    • 1995
  • Strontium selective chromatographic material $(Sr-Spec^{TM})$ was investigated for separation of radiostrontium from environmental soil and water sample. This chromatographic material has great capacity of binding of strontium ion in nitric acid media, and has selectivity to permit the separation of stontium from bulk amount of calcium. But the extraction of strontium was reduced by the other interfering ions such as K and Ba. So, in order to apply this material to the soil sample, prior removal treatment of K and Ba was needed. But the Sr-Spec material could provides simple and effective methods for the separation and removal of radiostrontium from liquid sample.

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Selective Removal of Mask by Mechanical Cutting for Micro-patterning of Silicon (마스크에 대한 기계적 가공을 이용한 단결정 실리콘의 미세 패턴 가공)

  • Jin, Won-Hyeog;Kim, Dae-Eun
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.2
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    • pp.60-67
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    • 1999
  • Micro-fabrication techniques such as lithography and LIGA processes usually require large investment and are suitable for mass production. Therefore, there is a need for a new micro-fabrication technique that is flexible and more cost effective. In this paper a novel, economical and flexible method of producing micro-pattern on silicon wafer is presented. This method relies on selective removal of mask by mechanical cutting. Then micro-pattern is produced by chemical etching. V-shaped grooved of about 3 ${\mu}m$ wide and 2 ${\mu}m$ deep has been made on ${SiO_2}m$ coated silicon wafer with this method. This method may be utilized for making microstructures in MEMS application at low cost.

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REACTIVITY AND DURABILITY OF V2O5 CATALYSTS SUPPORTED ON SULFATED TIO2 FOR SELECTIVE REDUCTION OF NO BY NH3

  • Choo, Soo-Tae;Nam, Chang-Mo
    • Environmental Engineering Research
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    • v.10 no.1
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    • pp.31-37
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    • 2005
  • The selective catalytic experiments using both sulfated/sulfur-free titania and V2O5/TiO2 catalysts have been conducted for NO reduction by NH3 in a packed-bed, down-flow reactor. The sulfated and vanadia loaded titania exhibited higher activity for NO removal than the sulfur-free catalysts, where > 90% NO removal was achieved over the sulfated V2O5/TiO2 catalyst between 280∼500 C. The surface structure of vanadia species on the catalyst surface played a critical role in the high performance of catalysts in which the existence of monomeric/polymeric vanadate is revealed by Raman spectra studies. Water vapor and SO2 were added to the reacting system for the catalyst deactivation tests. At higher temperatures (T ≥ 350 C), little deactivation was observed over the sulfated V2O5/TiO2 catalysts, showing good durability against SO2 and water vapor, which is compared with deactivation at lower temperatures.

Development of Oil-water Separator for the Effective Application of Highly Selective Membranes (고선택성 유수분리막 적용성 향상을 위한 유수분리장치 성능 개선 연구)

  • Choi, Kwang-Soon;Lee, Donghun;Uhm, Sunghyun
    • Applied Chemistry for Engineering
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    • v.30 no.1
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    • pp.39-42
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    • 2019
  • We report on the design of oil-water separators and the selection of materials for the effective application of highly selective membranes fabricated by commercial PET (polyester) fabrics. The waterproof ability of PET fabrics was optimized to improve the separation selectivity. The density of individual PET fabrics should be over $60g/m^2$, and the multi-layered structure is more favorable for the waterproof ability together with maintaining the removal efficiency. For the continuous adsorption and removal process, the rotating perforated cylinder was selected, and covered with membranes. Furthermore, more improved and stable removal efficiency was obtained by installing floating baffles which forces the oil content to move toward membranes.