• Title/Summary/Keyword: Natural Science and Engineering

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RNA viruses in Pleurotus ostreatus

  • Lee, Jung-Sun;Lee, Nam-Joo;Ha, Si-Jung;Kim, So-Yeon;Kang, Eun-Joo;Kang, Dong-Suk;Rho, Hyun-Su;Chang, Moo-Ung;Lee, Jong-Kyu;Lee, Kyung-Hee;Lee, Hyun-Sook
    • Proceedings of the Korean Society of Plant Pathology Conference
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    • 2004.10a
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    • pp.46-46
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    • 2004
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Preparation of a Porous Chitosan/Fibroin-Hydroxyapatite Composite Matrix for Tissue Engineering

  • Kim, Hong-Sung;Kim, Jong-Tae;Jung, Young-Jin;Ryu, Su-Chak;Son, Hong-Joo;Kim, Yong-Gyun
    • Macromolecular Research
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    • v.15 no.1
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    • pp.65-73
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    • 2007
  • Chitosan, fibroin, and hydroxyapatite are natural biopolymers and bioceramics that are biocompatible, biodegradable, and resorb able for biomedical applications. The highly porous, chitosan-based, bioceramic hybrid composite, chitosanlfibroin-hydroxyapatite composite, was prepared by a novel method using thermally induced phase separation. The composite had a porosity of more than 94% and exhibited two continuous and different morphologies: an irregularly isotropic pore structure on the surface and a regularly anisotropic multilayered structure in the interior. In addition, the composite was composed of an interconnected open pore structure with a pore size below a few hundred microns. The chemical composition, pore morphology, microstructure, fluid absorptivity, protein permeability, and mechanical strength were investigated according to the composition rate of bioceramics to biopolymers for use in tissue engineering. The incorporation of hydroxyapatite improved the fluid absorptivity, protein permeability, and tenacity of the composite while maintaining high porosity and a suitable microstructure.

Science and Technology of Natural Colorants (천연색소의 과학과 기술)

  • Jung, Chanhee;Lee, Jungwoo;Yoo, Dong Il
    • Textile Coloration and Finishing
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    • v.34 no.2
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    • pp.77-92
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    • 2022
  • Natural colorants are regarded as substitutes for synthetic colorants in the fields of fiber dyeing, hair dyeing, cosmetic, and food industries. The use of natural colorants has been increased in view of global environment and sustainability. However, scientific approach to the production is required because the supply of natural colorants depends on the climate, soil, and cultivation methods. This brief review contains the advances in science and technology related to natural colorants including characterization, analysis, CIEL*a*b* and Munsell color systems, and future prospects. For the characterization and the analysis of natural colorants, chromatography, some spectroscopic techniques (UV-Vis, FT-IR, NMR), mass spectrometry, and X-ray diffraction are generally used.

The simulation study on natural circulation operating characteristics of FNPP in inclined condition

  • Li, Ren;Xia, Genglei;Peng, Minjun;Sun, Lin
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1738-1748
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    • 2019
  • Previous research has shown that the inclined condition has an impact on the natural circulation (natural circulation) mode operation of Floating Nuclear Power Plant (FNPP) mounted on the movable marine platform. Due to its compact structure, small volume, strong maneuverability, the Integral Pressurized Water Reactor (IPWR) is adopted as marine reactor in general. The OTSGs of IPWR are symmetrically arranged in the annular region between the reactor vessel and core support barrel in this paper. Therefore, many parallel natural circulation loops are built between the core and the OTSGs primary side when the main pump is stopped. and the inclined condition would lead to discrepancies of the natural circulation drive head among the OTSGs in different locations. In addition, the flow rate and temperature nonuniform distribution of the core caused by inclined condition are coupled with the thermal hydraulics parameters maldistribution caused by OTSG group operating mode on low power operation. By means of the RELAP5 codes were modified by adding module calculating the effect of inclined, heaving and rolling condition, the simulation model of IPWR in inclined condition was built. Using the models developed, the influences on natural circulation operation by inclined angle and OTSG position, the transitions between forced circulation (forced circulation) and natural circulation and the effect on natural circulation operation by different OTSG grouping situations in inclined condition were analyzed. It was observed that a larger inclined angle results the temperature of the core outlet is too high and the OTSG superheat steam is insufficient in natural circulation mode operation. In general, the inclined angle is smaller unless the hull is destroyed seriously or the platform overturn in the ocean. In consequence, the results indicated that the IPWR in the movable marine platform in natural circulation mode operation is safety. Selecting an appropriate average temperature setting value or operating the uplifted OTSG group individually is able to reduce the influence on natural circulation flow of IPWR by inclined condition.

Synthesis and Characterization of New Anthracene-Based Blue Host Material

  • So, Ki-Ho;Park, Hyun-Tae;Shin, Sung-Chul;Lee, Sang-Gyeong;Lee, Dong-Hui;Lee, Kyeong-Hoon;Oh, Hyeong-Yun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Bulletin of the Korean Chemical Society
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    • v.30 no.7
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    • pp.1611-1615
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    • 2009
  • We designed new anthracene-based host material to increase color purity as well as device efficiency. The new blue host, 9,10-bis(2,4-dimethylphenyl)anthracene (BDA), has highly twisted structure and wide band gap due to ortho interaction between anthracene and introduced 2,4-dimethylphenyl substituents. BDA exhibited deep blue fluorescence in solution (${\lambda}_{max}$ = 410 nm) and in solid state (${\lambda}_{max}$ = 429 nm), respectively, with the wide optical band gap (E = 3.12 eV). Blue-light-emitting OLEDs using obtained host and 2% Flu-DPAN as emitter showed 8 cd/A of high efficiency as well as high color purity [CIE coordinates = (0.15, 015)].