• Title/Summary/Keyword: bio materials

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Formaldehyde and TVOC Emission of Bio-Composites with Attached Fancy Veneer

  • Lee, Byoung-Ho;Kim, Hee-Soo;Kim, Ki-Wook;Lee, Se-Na;Kim, Hyun-Joong
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.2
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    • pp.46-55
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    • 2008
  • This study assesses the formaldehyde and TVOC emissions from bio-composites with attached fancy veneer manufactured using wood flour and polypropylene (PP) measured using the Field and Laboratory Emission Cell (FLEC) method and 20 L small chamber method. To determine and compare the effects of the adhesive, samples were prepared with different manufacturing methods. In the FLEC result, the formaldehyde emission level of the bio-composites with attached veneer by hot-press was the lowest than pure bio-composite and bio-composite attached veneer using adhesive. The TVOC emission levels are similar to the formaldehyde emission. The TVOC emission level is very low in all of the samples except fancy veneer that is attached with bio-composites using adhesive. The TVOC emission varies depending on how attaching fancy veneer. The results of the 20 L small chamber method were very similar to those obtained with the FLEC, but the correlation was not perfect. However, the FLEC method requires a shorter time than the 20 L small chamber method to measure the formaldehyde and TVOC emissions. The internal bonding strength exceeded the minimum value of $0.4N/mm^2$ specified by the KS standard. All of the bio-composites with attached veneer satisfied the KS standard.

Antifungal Activities of Dimeric Sesquiterpenes, Shizukaols C and F, Isolated from Chloranthus japonicus Sieb.

  • Kang, Tae Hoon;Lee, Yun Me;Lee, Won Jung;Hwang, Eui Il;Park, Ki Duk;Choi, Gyung Ja;Moon, Jae Sun;Park, Ho-Yong;Kim, Sung Uk
    • Journal of Microbiology and Biotechnology
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    • v.27 no.7
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    • pp.1272-1275
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    • 2017
  • Two dimeric sesquiterpenes were separated from Chloranthus japonicus Sieb. and identified as shizukaols C and F. They exhibited potent antifungal activities ($MICs=4-16{\mu}g/ml$) in vitro against various plant pathogenic fungi (Pythium ultimum, Phytophthora infestans, Botrytis cinerea, Colletotrichum lagenarium, Alternaria kikuchiana, and Magnaporthe grisea). Shizukaol C showed 88% and 91% protective activities in the greenhouse against Puccinia recondita (wheat leaf rust) and Phytophthora infestans (tomato late blight), respectively, at $100{\mu}g/ml$; shizukaol F exhibited 93% antifungal activity against Puccinia recondita at the same concentration. Therefore, these compounds might serve as interesting candidates for effective antifungal agents.

Effect of pH and Temperature on the Electrochemical Reduction of Carbon Dioxide by Carbon Monoxide Dehydrogenase (일산화탄소탈수소화효소를 이용한 이산화탄소의 전기화학적 환원에 미치는 pH와 온도의 영향)

  • Shin, Jun-Won;Kim, You-Sung;Lee, Sang-Hee;Lee, Sang-Phil;Lee, Ho-Jun;Lim, Mi-Ran;Song, Ji-Eun;Shin, Woon-Sup
    • Journal of the Korean Electrochemical Society
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    • v.10 no.4
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    • pp.265-269
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    • 2007
  • The effects of experimental variables for the electrochemical reduction of carbon dioxide by Carbon Monoxide Dehydrogenase (CODH) were investigated. It shows the pH optimum at 6.3 where the feasibility of electro-chemical reduction and the stability of CODH compromise each other. The optimum temperature for the reduction was at $60^{\circ}C$ where the enzyme shows the optimum activity although the solubility of carbon dioxide decreases as increasing temperature.

Curing behavior of Photo-Curable Materials by Photo-Shrinkage Test (광원 경화형 소재의 수축률평가를 통한 광경화 거동 평가)

  • Park, Ji-Won;Bae, Kyung-Yul;Kim, Pan-Seok;Lim, Dong-Hyuk;Kim, Hyun-Joong;Cho, Jin-Ku;Kim, Baek-Jin;Lee, Sang-Hyeup
    • Journal of Adhesion and Interface
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    • v.11 no.2
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    • pp.57-62
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    • 2010
  • Photo-curable material can be crosslinked among molecules by light source such as UV and visible light materials. Material properties are controlled by crosslink reaction. Shrinkage is occured during the curing reaction of material structure. Phenomenon of shrinkage stress occurs inside the product and reduce the stability of the product causes problems. Heat shrink the evaluation of the phenomenon has been formalized. But the evaluation of photo shrink is not enough. In this experiment, real-time contract with shrinkage tester phenomena and analysis degree of shrinkage of the material differences. According to the research, experimental results and theoretical analysis of the results were big differences. Shrinkage, especially for a number of different functional groups that were very different theory. These differences are occurred by the molecular structure different and not enough reaction.