• Title/Summary/Keyword: bio materials

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Application of wood flour spacers for increasing OCC solid content in wet pressing process (II) (스페이서 사용에 의한 OCC 압착공정의 고형분 증대 (II))

  • Jung, Jae Kwon;Ji, Sung Jil;Seo, Yung Bum
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.3
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    • pp.24-33
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    • 2015
  • Linerboards containing wood flours were developed to increase solid contents in wet pressing process. Presence of wood flours in recycled fibers allowed passage of pressurized water at high wet pressing pressure, and increased solid contents while keeping the bulk of the board. The amount of wood flour addition should be controlled based on the intensity of the wet pressing pressure and the properties of the wood flours. Addition of cationic starch to the wood flour containing OCC furnish showed synergic increase of solid content and strength properties. Shapes of the wood flours such as spherical and rod type added to OCC furnish affected largely their solid content, drainage, and board physical properties.

Development of Auto-hydrolysis Method for Preparing Cotton Linter Regenerated Fibers of Textile Fabrics (방직용 재생펄프 제조를 위한 면 린터의 자기가수분해 공정 개발)

  • Sohn, Ha Neul;Park, Hee Jung;Seo, Yung Bum
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.47 no.6
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    • pp.81-88
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    • 2015
  • The molecular weight (MW) and crystallinity of cotton linter need to be controlled to be dissolved well in N-methylmorpholine N-oxide (NMMO) solvent for manufacturing regenerated fibers of clothing fabrics. Electron beam irradiation or sulfuric acid pre-treatment followed by alkaline peroxide bleaching has been used to control MW effectively and to improve brightness of cotton linter. Auto-hydrolysis of cotton linter without electron beam irradiation or chemical pre-treatment was found to be effective as an alternative pre-treatment method. Removal of metal ions, that hampered dissolution of cotton linter by NMMO, was also investigated when the auto-hydrolysis was accompanied with ionic polymers and chelating agent.

Preparation of CaO-SiO2-PEEK bio-composites and in-vitro Evaluation (CaO-SiO2-PEEK 생체복합체의 제조와 in-vitro 특성평가)

  • Kim Ill Yong;Cho Sung Baek;Kim Jong Ock;Shin Jong Woo;Lee Sung Ho;Park Joong Keun;Kim Taik Nam
    • Korean Journal of Materials Research
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    • v.14 no.4
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    • pp.287-292
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    • 2004
  • A bio-composites were prepared by mechanical mixing with bioactive sol-gel derived $CaO-SiO_2$ and organic PEEK for bone repairing hybrid materials. The composites were characterized by in-vitro test. A bonelike apatite was formed on the surface of all bio-composites in SBF test. The cell morphology and adhesion on the surface of the composites having below 30% PEEK were clearly observed in L929 cell experiment.

Security threats and Review for FinTech (핀테크 보안 위협 및 고찰)

  • Joo, Jae Woong;Wu, DaMing;Park, Jong Hyuk
    • Proceedings of the Korea Information Processing Society Conference
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    • 2015.04a
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    • pp.412-414
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    • 2015
  • 최근 금융과 IT가 결합한 핀테크 산업이 빠르게 성장하고 있다. 전통적 금융 서비스에서 벗어나 소비자 접근성이 높은 인터넷, 모바일 기반 디바이스의 장점을 활용하여 송금, 결제, 자산관리 등 다양한 분야의 금융서비스를 제공한다. 하지만 핀테크 기술 발전으로 네트워크, 클라이언트, 시스템 등 각각의 부문에서 새로운 보안 위협 요소가 증가 할 것이다. 본 논문에서는 핀테크 보안의 고려사항과 연구동향에 대해 살펴보고 현재 핀테크 분야에서 보안이 적용된 시스템에 대해 분석하고 취급되는 정보보호의 중요성에 대해 고찰한다.

A Study on Schema Of Recent APT Attack And Plan For Reaction (최근 APT 공격의 형태 및 대응 방안 연구)

  • Ho, Im Wan;Im, Hyungjin;Park, Jong Hyuk
    • Proceedings of the Korea Information Processing Society Conference
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    • 2015.04a
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    • pp.421-423
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    • 2015
  • 인터넷을 통한 악성코드의 확산이 나날이 증가하고 있는 가운데 특정 대상을 목표로 하여 지능적이고 지속적으로 공격하는 Advanced Persistent threat(APT) 공격이 이슈가 되고 있다. APT 공격은 특정 시스템을 목표로 하여 공격하기 때문에, 실제 공격이 성공 했을 시에는 그 피해가 더 치명적일 수 있다. 본 논문에서는 APT공격의 정의를 살펴보며, 최근에 발생하는 일반적인 APT 공격의 형태와 그 대응 방안에 대해 논의한다.

Development of functional food products with natural materials derived from marine resources (건강기능성 수산식품소재의 개발)

  • Ryu, BoMi;Jeon, You-Jin
    • Food Science and Industry
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    • v.51 no.2
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    • pp.157-164
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    • 2018
  • Recently demand for safer and healthier food has augmented with advancements in health conditions. Food ingredients with yet to be known safety and functionality, are being investigated for their safety or detrimental effects. The Ministry of Food and Drug Safety has introduced "health functional food" by the "Health Functional Food Act" to evaluate bio-functional and safety properties of raw materials using standard methods including in-vitro and in-vivo testing before human consumption. Despite recent growth in net worth of domestic functional food market, most of the raw materials are not from local Korean industries with own research and development, and mostly terrestrial not marine resources. Geographically, Korea has access to diverse marine bio-resources that need to be managed and utilized sustainably. Recently, diverse novel physiologically active substances have been reported from marine organisms. Hence, the development of functional foods from marine bio-resources is considered as an inevitably important task.

Zirconia Ceramic Powder Coating of Ti-6AI-4V by Laser Cladding (레이저 클래딩을 이용한 Ti-6AI-4V의 Zirconia 세라믹 분말 코팅)

  • Kang, Kyung-Ho;Kim, Jae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.7
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    • pp.783-788
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    • 2011
  • The recent development of bio-ceramic material is being studied in various bio-material engineering field. There are lots of technical difficulties because manufacturing or bonding technique are required bio-friendliness, cleanliness and persistence. Zirconia ceramic powder is cladded on Ti-6AI-4V metallurgically by laser cladding processing. Laser cladding system with powder feeding delivery is designed and manufactured for optimum processing condition. Increasing of manufacturing speed and good quality of clad layer are achieved by application of preheating of substrate before laser cladding. The thin dilution and good clad layer on the substrate are obtained for applications of bio-materials such as the dental materials and the articulated joints of human body.

Sugar Extraction by Pretreatment and Soda Pulping From Cattail (Typha latifolia L.) (1) Extraction of Sugar (부들의 전처리를 통한 당의 추출과 소다펄프화에 관한 연구 (1) 당 추출)

  • Lee, Sung-Eun;Kim, Wan-Jung;Son, Mi-Kyung;Seo, Yung-Bum
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.42 no.2
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    • pp.88-94
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    • 2010
  • Cattail (Typha L.) was used as a raw material for producing both bio-ethanol and pulp for papermaking at the same time. Pretreatments of cattail stems and leaves with acid ($H_2SO_4$) and alkali (NaOH) in three different addition levels were studied before soda pulping. The acid pretreatment gave reducing sugar of 15.2% of initial weight, but alkali pretreatment close to 1%. Soda pulping of the pretreated cattail gave 3% reduction in pulp yield and less bonding properties in paper; however, refining of the pulp from the pretreated cattail with alkali restored their fiber bondings up to that of the pulp from no-pretreated cattail at equivalent freeness.

Molecular Design of New Organic Electroluminescence Materials: DCM Derivatives

  • Seong, See-Yearl;Park, Sung-Soo;Seo, Jeong-In;No, Kyoung-Tai;Hong, Jong-In;Park, Su-Jin;Choi, Seung-Hoon;Lee, Han-Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.178-180
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    • 2003
  • We performed semiempirical (AMl and ZINDO) and ab initio (HF and DFT) calculations, to investigate molecular structures and optical properties of DCM and its derivatives. DCM and its derivatives are used as a red fluorescent dopant of the organic electroluminescent host materials, $Alq_3$. We have studied the relationship between the molecular structure and the optical properties of these molecules for the improvement of EL efficiencies. Wavelength at the absorption maximum was found to be red-shifted when the molecule is substituted with both strong electron donating and withdrawing functional groups. A new red fluorescent dye was predicted by QSPR study based on calculations and experimental data.

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