• 제목/요약/키워드: Dilution Effect

검색결과 622건 처리시간 0.023초

Candida albicans의 시험관 희석법에 의한 항균력 검사시 배지가 항균력에 미치는 영향 (Effect of Culture Medium on Results of Maerobroth Dilution Antifungal Susceptibility Testing of Candida albicans)

  • 고춘명;김수기
    • 대한미생물학회지
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    • 제22권3호
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    • pp.301-307
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    • 1987
  • A total of 42 strains of Candida albicans were examined for susceptibility to three antifungal agents, amphotericin B(AMB), 5-fluorocytosine(5-FC), and ketoconazole(KTZ), using defined medium, synthetic amino acid medium-fungal(SAAM-F), supplemented yeast nitrogen base(SYNB) and undefined medium Sabouraud's dextrose broth(SDB) and Kimmig broth media. A tube dilution method was used with minimum inhibitory concentrations(MICs) determined after incubation for 24 hour and 48 hours. All testes were performed in duplicate. In general, MICs were more reproducible after 48 hour of incubation. Forthermore, MICs determined after incubation for 48 hours were significantly higher than those determined after 24 hours. The actural MICs obtained with the different antifungal agents were clearly influenced by the test medium used. The rank order of AMB MICs according to the test medium was as follows: SAAM-F>SYNB>SDB>Kimmig broth. With 5-FC, the following pattern was observed: SYNB>SAAM-F>SDB>Kimmig borth. For ketoconazole, the MICs according to the test medium was SAAM-F>SDB>SYNB> Kimmig broth. In amphotericin B, the MICs mean value with the test medium was as follows: SDB, 0.24 mcg/ml; Kimmig broth, 0.29 mcg/ml; SYNB, 0.21 mcg/ml and SAAM-F, 0.15mcg/ml. The actural value of 5-FC was; SDB, 37.20 mcg/ml; Kimmig broth, 67.41mcg/ml; SYNB, 21.29 mcg/ml and SAAM-F, 24.61 mcg/ml and in ketoconazole, the MICs value was; SDB, 1.83 mcg/ml; Kimmig broth, 4.08 mcg/ml; SYNB, 1.95 mcg/ml and SAAM-F, 1.41 mcg/ml. The results of this investigation suggested that broth dilution susceptibility testing of yeast and yeast-like fungi are best performed with an incubation period of 48 hours. Furthermore, medium composition can significantly influence the results of such testing.

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Evaluation of antibacterial activity against Candida albicans according to the dosage of various denture cleansers

  • Bae, Cha-Hwan;Lim, Yun-Kyong;Kook, Joong-Ki;Son, Mee-Kyoung;Heo, Yu-Ri
    • The Journal of Advanced Prosthodontics
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    • 제13권2호
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    • pp.100-106
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    • 2021
  • PURPOSE. The purpose of this study is to compare the antibacterial activity of currently purchasable denture cleansers against Candida albicans. Materials and methods: This study used tablet-type denture cleansers, PolidentⓇ, CoolingdentⓇ and FittydentⓇ, along with liquid denture cleansers, HexamedineⓇ, ListerineⓇ and Apple vinegarⓇ. The antibacterial activities of denture cleansers were evaluated based on the number of C. albicans and concentrations of the denture cleansers. Results. In the 0.5 × 106 cfu/㎖ culture medium, the C. albicans' death rate of PolidentⓇ was significantly lower than those of FittydentⓇ, HexamedineⓇ, ListerineⓇ, and Apple vinegarⓇ(P<.05). In the 0.5 × 107 cfu/, the C. albicans' death rates of PolidentⓇ and CoolingdentⓇ were significantly lower than those of FittydentⓇ, HexamedineⓇ, ListerineⓇ and Apple vinegarⓇ(P<.05). The C. albicans' death rates of PolidentⓇ and CoolingdentⓇ were significantly decreased at 0.02 g and 0.01 g. The C. albicans' death rate of FittydentⓇ was significantly decreased at 0.005 g (P<.05). The C. albicans' death rate of HexamedineⓇ was significantly decreased at 1/16 dilution. The C. albicans' death rate of ListerineⓇ was decreased at 1/8 dilution, and the antibacterial activity of Apple vinegarⓇ was decreased at 1/4 dilution (P<.05). Conclusion. As the number of C. albicans increased, the antibacterial activities of the denture cleansers decrease. In the tablet-type denture cleanser, all denture cleansers showed 100% C. albicans' death rate when used at a dose of 1 tablet. One denture cleanser showed the same antibacterial effect with only 1/3 of a tablet. In the liquid type denture cleanser, the level of dilution required was different for each denture cleanser.

고이동도 TFTs 구현에 nc-Si:H 박막의 수소 희석비와 결정성이 미치는 영향 (Effect of Hydrogen Dilution Ratio and Crystallinity of nc-Si:H Thin Film on Realizing High Mobility TFTs)

  • 최지원;김태용;팜뒤퐁;조재웅;최자양;신동욱;이준신
    • 한국전기전자재료학회논문지
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    • 제34권4호
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    • pp.246-250
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    • 2021
  • TFTs technologies with as high mobility as possible is essential for high-performance large displays. TFTs using nanocrystalline silicon thin films can achieve higher mobility. In this work, the change of the crystalline volume fraction at different hydrogen dilution ratios was investigated by depositing nc-Si:H thin films using PECVD. It was observed that increasing hydrogen dilution ratio increased not only the crystalline volume fraction but also the crystallite size. The thin films with a high crystalline volume fraction (55%) and a low defect density (1017 cm-3·eV-1) were used as top gate TFTs channel layer, leading to a high mobility (55 cm2/V·s). We suggest that TFTs of high mobility to meet the need of display industries can be benefited by the formation of thin film with high crystalline volume fraction as well as low defect density as a channel layer.

가스터빈에서 SNG 연료 조성에 대한 희석제의 배기배출물 저감효과에 대한 실험적 연구 (Experimental Study on Dilution Effect of Exhaust Gas in SNG Combustion on a Model Gas Turbine)

  • 주성필;윤지수;김정진;김성헌;윤영빈
    • 한국항공우주학회지
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    • 제44권7호
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    • pp.603-610
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    • 2016
  • 본 논문에서는 석탄으로부터 생성된 합성천연가스(SNG)의 다양한 연료 조성에 대한 배기가스 배출 특성 및 희석제에 대한 NOx배출 저감에 대해 기술하였다. 예혼합거리가 짧은 부분 예혼합 가스터빈 연소기에서 SNG 연료조성에서의 수소 비율과 입열량, 당량비를 조절해 가며 연소특성을 관찰하였다. 수소 비율에 따른 NOx 배출지수는 유사하게 나타났고, 화염가시화를 통해 화염의 특성을 파악할 수 있었다. CO 배출의 경우 당량비 1 구간에서 특이점이 나타났으며, 이를 화염의 자발광 이미지와 자발광 강도를 통하여 원인을 파악할 수 있었다. 또한 높은 NOx 배출을 저감하기 위하여 질소($N_2$)와 이산화탄소($CO_2$) 희석제를 사용하여 희석제 공급량에 대한 저감 효과를 파악하였다. 이로부터 희석제의 비열과 열용량이 연소로부터 발생한 연소열을 흡수하여 열화에 의한 NOx 배출을 저감하는 효과를 확인하였다.

SAW 용접금속 성질에 미치는 질소함량의 영향 (Effect of Nitrogen Content on SAW Weld Metal Properties)

  • 변지철;방국수;이종봉;안영호
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2005년도 춘계학술발표대회 개요집
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    • pp.147-149
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    • 2005
  • Effect of nitrogen content on SAW weld metal properties were investigated. Weld metal nitrogen content increased with an increase of base metal nitrogen content due to dilution. High nitrogen content in weld metal resulted in high free nitrogen content, and consequently reduced impact toughness due to, mainly, strain aging effect.

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수소화된 비정질 실리콘 박막의 결정화에 수소의 희석비가 미치는 영향 (The effect of hydrogen dilution ratio on the crystallization of hydrogenated amorphous silicon thin films)

  • 이유진;신진국
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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    • pp.98-98
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    • 2003
  • 비정질 실리콘 박막을 태양전지, 박막 트랜지스터, 이미지 센서, 컬러 디텍터 등에 적용하기 위한 많은 연구가 진행되고 있다. 이중 태양전지에 적용하기 위한 비정질 실리콘 박막은 p/i/n 다이오드 구조를 형성하게 되는데, 태양전지의 효율을 증가시키기 위해 결정질을 형성하거나 실리콘 화합물 박막을 적용한다. 본 연구에서는 비정질 태양전지의 흡수층(absorption layer)으로 사용되는 수소화된 비정질 박막의 결정화에 수소의 희석비가 미치는 영향을 파악하고자 하였다. PECVD 장비로 실란(SiH$_4$)과 수소(H$_2$) 가스를 이용하여 실리콘 박막을 증착하였고, 수소의 희석비(dilution ratio)를 변화시켜 비정질 실리콘 박막 내에 결정질 실리콘이 형성되는 정도를 관찰하였다. SEM과 Raman Spectroscopy를 이용해 박막의 두께 및 결정화도를 측정하였다. 실란에 대한 수소의 희석비가 증가할수록 증착률은 낮아지지만, 결정화도가 높아지는 것을 관찰할 수 있었다. 본 연구에서 형성한 결정질 실리콘 박막을 태양전지의 흡수층에 적용하면 효율 증가에 크게 기여할 것으로 판단된다.

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석탄가스 난류비예혼합 화염장의 해석 (Numerical Analysis for the Detailed Structure of Syngas Turbulent Nonpremixed Flames)

  • 이정원;김창환;김용모
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.775-778
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    • 2007
  • The present study numerically investigate the detailed structure of the syngas diffusion flames. In order to realistically represent the turbulence-chemistry interaction, the transient flamelet model has been applied to simulate the combustion processes and $NO_X$ formation in the syngas turbulent nonpremixed flames. The single mixture fraction formulation is extended to account for the effects of the secondary inlet mixture. Computations are the wide range of syngas compositions and oxidizer dilutions. Based on numerical results, the detailed discussion has been made for the effects of syngas composition and oxidizer dilution on the structure of the syngas-air and syngas-oxygen turbulent nonpremixed flames.

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랜드마크 기반 비전항법시스템에서 랜드마크의 기하학적 배치에 대한 3차원 항법오차 (Three-dimensional Navigation Error for Landmarks' Geometry in Landmark-based Vision Navigation Systems)

  • 김영선;황동환
    • 전기학회논문지
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    • 제63권8호
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    • pp.1104-1110
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    • 2014
  • This paper investigates geometric effect of landmarks on three-dimensional navigation error in landmark-based vision navigation systems. Dilution of precision is derived for landmark measurement error on the focal plane of the camera and separately expressed in position DOP and attitude DOP. Values of DOP are observed for various configurations of landmarks.

H2/CO비, 희석량, 메탄/석탄가스비가 합성가스용 가스터빈의 연소특성에 미치는 영향 (Effect of H2/CO Ratio, Dilution Ratio, and Methane/Syngas Ratio on Combustion Characteristics of Syngas Turbine)

  • 이민철;윤영빈
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.59-60
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    • 2012
  • This paper describes gas turbine combustion characteristics of synthetic gas which is mainly composed of hydrogen and carbon monoxide. The combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, liner and dump plane, and flame structure were investigated when changing when changing $H_2:CO$ ratio, dilution ratio, and $CH_4:syngas$ ratio. From the results, quantitative relationships are derived between key aspects of combustion performance, notably NOx emission. It is concluded that NOx emission of syngas is strongly influenced by the diluent heat capacity and combustion instability. Moreover, NOx control method using diluents such as $N_2$, $CO_2$, steam is verified.

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