• Title/Summary/Keyword: Chemical industry

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Effect of Mechanical Impact Treatment on Fiber Morphology and Handsheet Properties

  • Yung B. Seo;Kim, Dukki;Lee, Jong-Hoon;Yang Jeon
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2001.11a
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    • pp.183-199
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    • 2001
  • Alternative way of shaping fibers suitable for papermaking was introduced. Impact refining, which was done simply by hitting wet fibers with a metal weight vertically, was intended to keep the fibers from shortening and to cause mostly internal fibrillation. Virgin chemical pulp, its recycled one and OCC were used in the experiment. It was noticed from the experiment that impact refining on virgin chemical pulp kept the fiber length and Increased bonding properties greatly, However, in the recycled fibers from the chemical pulp, fiber length and bonding properties were decreased. In OCC, which seems to contain fractions of semi-chemical pulp and mechanical pulp (GP), and which is recycled pulp from corrugated boxes, fiber length and bonding properties were decreased disastrously. We believe recycled cellulosic fibers (recycled chemical pulp and OCC in this case), which went through hornification, were less resistant to the mechanical impact than virgin chemical pulp. For virgin chemical pulp, impact refining allowed no significant fiber length shortening, high WRV, and high mechanical strength.

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Optimal Water-cooling Tube Design for both Defect Free Process Operation and Energy Minimization in Czochralski Process (무결정결함영역을 유지하면서 에너지를 절감하는 초크랄스키 실리콘 단결정 성장로 수냉관 최적 설계)

  • Chae, Kang Ho;Cho, Na Yeong;Cho, Min Je;Jung, Hyeon Jun;Jung, Jae Hak;Sung, Su Whan;Yook, Young Jin
    • Current Photovoltaic Research
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    • v.6 no.2
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    • pp.49-55
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    • 2018
  • Recently solar cell industry needs the optimal design of Czochralski process for low cost high quality silicon mono crystalline ingot. Because market needs both high efficient solar cell and similar cost with multi-crystalline Si ingot. For cost reduction in Czochralski process, first of all energy reduction should be completed because Czochralski process is high energy consumption process. For this purpose we studied optimal water-cooling tube design and simultaneously we also check the quality of ingot with Von mises stress and V(pull speed of ingot)/G(temperature gradient to the crystallization) values. At this research we used $CG-Sim^{(R)}$ S/W package and finally we got improved water-cooling tube design than normally used process in present industry. The optimal water-cooling tube length should be 200mm. The result will be adopted at real industry.

Application of Silica-supported Ionic Liquid Catalysts to Cycloaddition of CO2 (CO2 부가반응에 적용된 Silica 담지 이온성 액체 촉매)

  • Kim, Dong-Woo;Kim, Hyeon-Gook;Cho, Deug-Hee
    • Applied Chemistry for Engineering
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    • v.27 no.3
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    • pp.239-244
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    • 2016
  • The catalytic applicability of various ionic liquids immobilized on different silica-supports such as amorphous, SBA, MCM and commercial silica for the cycloaddition of $CO_2$ and epoxides is reviewed in this work. The effects of different structures of supported ionic liquids and silica supports in the synthesis cyclic carbonate by the cycloaddition of $CO_2$ have been remarked. The studies revealed that ionic liquids possessing functional groups or metals exhibited increased catalytic performance towards cyclic carbonate synthesis. Moreover, the reusability of SSIL catalyst and mechanism for the cycloaddition of $CO_2$ were studied.

Reactivity Considerations with Miscibility of Process Gases in Semiconductor industry (반도체 산업 공정가스의 혼화성에 따른 반응성 고찰)

  • Lee, Keun Won
    • Journal of the Korean Institute of Gas
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    • v.20 no.4
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    • pp.15-24
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    • 2016
  • In the semiconductor industry, the risk of chemical accidents due to miscibility between the many types of chemicals and leakage of toxic chemicals has increased. In order to evaluate the reactivity with miscibility of chemicals, experimental method is the most reliable, but there is a time and cost limitations to be evaluated through experiment all the chemicals. In the study, the reactivity of process gases in the semiconductor industry was considered by the CRW (Chemical Reactivity Worksheets) 3.0 program developed by US NOAA (National Oceanic and Atmospheric Administration) and EPA. The reactivity informations with the miscibility of process gases for semiconductor industry provided, and also a KOSHA guide for the storage/separation of gas cylinders in dispensing cabinets in the semiconductor industry was proposed.