• Title/Summary/Keyword: hfa

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Flow and Strength Properties of Non-cement Matrix According to Replacement Ratio of Dyeing Sludge Carbide Based on the Blast Furnace Slag (고로슬래그를 기반으로 염색슬러지 탄화물 치환율에 따른 무시멘트 페이스트의 유동 및 강도특성)

  • Kim, Tae-Hyun;Lee, Yong;Sin, Jin-Hyun;Kim, Weon-Jeong;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.104-105
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    • 2016
  • From the Industrial Revolution by past to the present, Carbon emission quantity increase rapidly around the globe. Depending on this status, Also global warming are accelerated rapidly, in order to solve this status, the Climatic Change Convention is held now on. So, On this study, Utilizing the BFS, HFA, DS that we get the basic data of the cementless paste.

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Photo-alignment of Low-molecular Mass Nematic Liquid Crystals on Photochemically Bifunctional Chalcone-epoxy Film by Irradiation of a Linearly Polarized UV Light

  • Choi, Dong-Hoon;Cha, Young-Kwan
    • Bulletin of the Korean Chemical Society
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    • v.23 no.4
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    • pp.587-592
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    • 2002
  • Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthe-sized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photoinitiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization. Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

Two-Stage Microbial Biotransformation for the Production of 6-Dodecen-4-olide (Butter Lactone) from Plant Oils Containing Unsaturated Fatty Acids (불포화 지방산 함유 식물유를 이용한 천연 6-Dodecen-4-oilde (Butter Lactone) 생산을 위한 2-Stage Microbial Biotransformation)

  • Kwon, Soon-Hyang;Kim, Kyoung-Ju;Kim, Yang-Hwi Augustine
    • Korean Journal of Microbiology
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    • v.43 no.2
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    • pp.130-136
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    • 2007
  • Natural 6-dodecen-4-olide (Butte lactone) was produced from plant oils containing high unsaturated fatty acids via two-stage microbial hiotransformation. After unsaturated fatty acids were liberated from plant oil by microbial lipase, these were converted to optically active hydroxyl fatty acid (HFA) by hydroxylation reaction of Pseudomonas sp. NRRLB-2994. When safflower oil containing >75% unsaturated fatty acid, linoleoic acid wasused, Pseudomonas sp. produced 8g/L of 10-hydroxy-12(z)-octadecanoicacid with average of 39.2% bioconversion efficiency during 48 hr biotransformation period. The recovered 10-hydroxy-12-octadecanoic acid was further bioconverted to 4-hydroxy-6-dodecenoic acid via partial ${\beta}-oxidation$ by Yarriowia lipolytica ATCC34088. 4-hydroxy-6-dodecenoic acid in culture was lactonized by lowering pH to 4.0 using $4N\;H_{2}SO_{4}$ and heating for 5 min to 6-dodecen-4-olide (Butter lactone). Natural 6-dodecen-4-olide had characteristic aroma properties when compared to 6-dodecan-4-oilde (dodecalactone) and 4-decen-4-olide (decalactone).

Synthesis of Fluorine Modified Polyurethane and Surface Modification (불소 변성 폴리우레탄의 합성과 표면 개질)

  • Lim, Chul Hwan;Choi, Hee Sung;Noh, Si Tae
    • Applied Chemistry for Engineering
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    • v.10 no.6
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    • pp.913-916
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    • 1999
  • Fluorine modified diisocyanate(FMD) was synthesized from tris(6-isocyanatohexyl)isocyanurate(TIHI) and N-ethyl-N-2-hydroxyethyl-perfluorooctanesulfonamide(HFA). Fluorine modified polyurethane(FMPU) was also synthesized from FMD and poly(tetramethylene) glycol(PTMG). Modified polyurethanes were made by blending FMPU into the polyester type base polyurethane(BPU). Surface and thermal properties of the blended BPU film was measured by contact angle measurement and DSC. As the amounts of FMPU was increased from 0 wt % to 1 wt %, the surface energy was dramatically decreased from 47.82 dyne/cm to 17.64 dyne/cm. But we observed little change of the contact angle with further increase in the amount of the FMPU up to 10 wt %. The data meant that the surface of the blended polyurethanes was hydrophobic due to the surface arrangement of the fluorine containing moiety in FMPU. Phase separation was induced by the incompatibility of FMPU and BPU for the samples having over 5 wt % of FMPU. The thermal analysis data of these samples showed the thermal behavior of the FMPU itself.

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Characteristics and Drug Release Profiles of Multilamellar Vesicle(MLV) and Microemulsified Liposome(MEL) Entrapped 5-Fluorouracil and Its derivatives (5-Fluorouracil과 그 유도체를 봉입한 Multilamellar Vesicle(MLV)과 Microemulsified Liposome(MEL)의 특성 및 약물방출 거동)

  • Jee, Ung-Kil;Park, Mok-Soon;Lee, Gye-Won;Lyu, Yeon-Geun
    • Journal of Pharmaceutical Investigation
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    • v.25 no.3
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    • pp.249-264
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    • 1995
  • Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

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Conversion of Unsaturated Food Fatty Acids into Hydroxy Fatty Acids by Lactic Acid Bacteria

  • Kim, Myung-Hee;Park, Mee-Seung;Chung, Chang-Ho;Kim, Cheong-Tae;Kim, Youn-Soon;Kyung, Kyu-Hang
    • Journal of Microbiology and Biotechnology
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    • v.13 no.3
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    • pp.360-365
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    • 2003
  • The ability of 19 lactic acid bacteria to produce hydroxy fatty acids (HFAs) from unsaturated food fatty acids (USFAs) was tested. HFAs are related to human ailments, including steatorrhea. All the cultures produced HFAs from USFAs, unless their growth was inhibited by free USFAs. Lactococcus lactis subsp. lactis KFRI 131 converted oleic, linoleic, and linolenic acid into 10-hydroxyoctadecanoic acid (10-HODA), 10-hydroxyoctadecaenoic acid (10-HODEA), and 10-hydroxyoctadecadienoic acid (10-HODDEA), respectively. Both a USFA and a surfactant were needed for the bacterium to convert the fatty acid into the corresponding HFA. It was apparent that the production of 10-HODA was growth-related, while that of 10-HODDEA was not. It was unclear whether the production of 10-HODEA was growth-related.

Significant enhancement of critical current density by effective carbon-doping in MgB2 thin films

  • Ranot, Mahipal;Lee, O.Y.;Kang, W.N.
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.2
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    • pp.12-15
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    • 2013
  • The pure and carbon (C)-doped $MgB_2$ thin films were fabricated on $Al_2O_3$ (0001) substrates at a temperature of $650^{\circ}C$ by using hot-filament-assisted hybrid physical-chemical vapor deposition technique. The $T_c$ value for pure $MgB_2$ film is 38.5 K, while it is between 30 and 35 K for carbon-doped $MgB_2$ films. Expansion in c-axis lattice parameter was observed with increase in carbon doping concentration which is in contrast to carbon-doped $MgB_2$ single crystals. Significant enhancement in the critical current density was obtained for C-doped $MgB_2$ films as compared to the undoped $MgB_2$ film. This enhancement is most probably due to the incorporation of C into $MgB_2$ and the high density of grain boundaries, both help in the pinning of vortices and result in improved superconducting performance.

Measurement of Flow Field Downstream of Polyurethane Artificial Heart Valve with Floating Valve Leaflet (열림판이 지지대에 고정되지 않은 폴리우레탄 인공판막 하류의 유동장 측정)

  • Kim, J.K.;Sung, J.;Chang, J.K.;Min, B.G.;Yoo, J.Y.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.247-248
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    • 1998
  • The effect of unattached valve leaflet on flow field downstream of a floating and flapping polyurethane heart valve prosthesis was investigated. With a triggering system and a time-delay circuit the instantaneous velocity field downstream of the valve was measured by particle image velocimetry (PIV) in conjunction with the opening posture of a flexible valve leaflet during a cardiac cycle. Reynolds shear stress distribution was calculated from the velocity fields and wall shear stress was directly measured by hot-film anemometry (HFA). The floating motion of the valve leaflet resulted in the reduction of pressure drop and recirculating flow region downstream of the valve.

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Distribution of Heat and Smoke Related to Openings in Hise-Rise Apartment Building Fires (고층 공동주택의 개구특성에 따른 화재시 열.연기유동에 관한 연구)

  • 이지희
    • Fire Science and Engineering
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    • v.15 no.2
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    • pp.59-79
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    • 2001
  • The paper proposes alternatives for fire safety in architectural planning through heat-smoke distribution related to openings so that we decrease casualty and property loss by fire and lay a great emphasis on building high-rise apartments with consideration of fire safety in Korea. An analysis program(HFA-Heat Fluid Analysis) is built to perform simultaneously numerical analysis and experimental analysis on rooms, units and buildings. In consequence, on the first, fire prevention methods are required to be set up related to openings for design rooms since the flow of heat and smoke is influenced by the type of openings in high-rise apartments. Second, the numerical analysis showed that different planning types cause to show differences in the spreading time of heat and smoke to design the units of high-rise apartments. On the third, each unit building showed different fire behavior depending on openings by numerical analysis and small scaled experiment on heat and smoke flow.

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A comparison and analysis on amounts of physical activity between young children with mental retardation and young children with normal condition using accelerometer (가속도센서를 이용한 정신지체유아와 일반유아의 신체활동량 비교 분석)

  • Hwanag, Sun-Young;Choi, Kyung-Nam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1869-1873
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    • 2008
  • The purpose of this study is to compare and analyze the amount of physical activity between young children with mental retardation and young children with normal condition using accelerometer. Six children (three children with retardation and other three children with normal condition) were selected as a subject on this research. And measurement of this research was done with the following items;(1)numpeaks accelerometer transverse; PAT, (2) numpeaks accelerometer longitudinal;PAL, (3)heat flux average original rate; HFA, (4) steps per minute(SPM), (5)GSR average. The amount of physical activity for young children with mental retardation shows that they move less that young children with normal condition; young children with mental retardation (PAT-$2.94{\pm}0.60$, PAL-$4.97{\pm}0.650$, young children with normal condition(PAT-$4.50{\pm}0.95$, and PAL-$6.05{\pm}0.87$). This suggests that young children with mental retardation lacks physical ability. And the amount of physical activity for young children with mental retardation was less compared with young children with normal condition. It is concluded that many programs for young children with mental retardation to have more interest and act fast should be introduced and developed in educating young children with mental retardation.