• Title/Summary/Keyword: solid media

검색결과 519건 처리시간 0.032초

Pyrromethene 597 고체 색소 레이저의 제작 및 출력 특성 (Fabrication and lasing performance of Pyrromethene 597 dye in solid-state host media)

  • 이희철;김용평
    • 한국광학회지
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    • 제16권2호
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    • pp.146-151
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    • 2005
  • PMMA에 pyrromethene 597(PM597) 색소를 주입하여 고체 색소를 제작한 후 그 레이저 출력특성을 분석하였다. 펌핑 광원으로 Q-스위치 Nd : YAG 레이저의 제 2 고조파를 사용하여 발진 중심파장 585 nm에서 최대 광 변환효율 $76\%$를 얻었다. 광안정성을 증가시키기 위해 단일항 에너지 상태의 산소 제거제인 DABCO(1,4-diazabicyclo [2,2,2]octane)를 주입하여 반복율 4 Hz, 출력에너지 250 mJ, 100,000번 이상의 펄스 출력을 얻었다.

감압법을 이용한 메탄하이드레이트 생산에 대한 수치적 연구 (Numerical Study on the Production of Methane Hydrate by Depressurization Method)

  • 김진홍;천원기;김남진
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.519-523
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    • 2007
  • Gas(or methane) hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose a large variety of guest gas molecules. The natural gas hydrate crystal may exist at low temperature above the normal freezing point of water and high pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the earth and many production schemes are being studied. In the present investigation, depressurization method was considered to predict the production of gas and the simulation of the two phase flow - gas and water - in porous media is being carried out. The simulation show about the fluid flow in porous media have a variety of applications in industry. Results provide the appearance of gas and water production, the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pressure front.

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다공성 매질 내에서 메탄 하이드레이트의 분해에 의한 2 상 유동 해석 (Simulation of Two Phase Flow in Porous Media After Disso of Methane Hydrates)

  • 장동근;김남진;이재용;김종보
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집B
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    • pp.241-246
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    • 2000
  • Gas hydrates are solid solutions when water molecules are linked through hydrogen bondin create host lattice cavities that can enclose a large variety of guest gas molecules. The natural hydrate crystal may exist at low temperature above the normal freezing point of water and pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the ear many production schemes are being studied. In the present investigation, depressurization method considered to predict the production of gas and the simulation of the two phase flow - gas and - in porous media is being carried out. The simulation show about the fluid flow in porous have a variety of applications in industry. Results provide the appearance of gas and water prod the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pl front.

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동결과정을 포함한 다공층에서 자연대류에 대한 유한요소 해석 (Finite element solutions of natural convection in porous media under the freezing process)

  • 이문희;최종욱;서석진;박찬국
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.51-56
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    • 2000
  • The Finite Element Solutions Is reported on solid-liquid phase change in porous media with natural convection including freezing. The model is based on volume averaged transport equations, while phase change is assumed to occur over a small temperature range. The FEM (Finite Element Method) algorithm used in this study is 3-step time-splitting method which requires much less execution time and computer storage the velocity-pressure integrated method and the penalty method. And the explicit Lax-Wendroff scheme is applied to nonlinear convective term in the energy equation. For natural convection including melting and solidification the numerical results show reasonable agreement with FDM (Finite Difference Method) results.

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Nanocomposite 이용한 NFR Media 커버층 특성연구 (Nanocomposite Cover-layer for NFR Media)

  • 김진홍;이준석;서정교
    • 정보저장시스템학회논문집
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    • 제3권1호
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    • pp.17-22
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    • 2007
  • [ $TiO_2$ ] nanoparticles are added into UV curable resin to increase the refractive index of the cover-layer which is laminated on the media for cover-layer incident NFR. High refractive index is required for the cover-layer operating for the solid immersion lens optics with high effective numerical aperture. The eyepattern could be achieved from the cover-layer coated 20 GB ROM disc in which the refractive index of the cover-layer was 1.75, but the gap servo was unstable due to the rough surface of the cover-layer. Even though the light loss due to the nanoparticles is not serious, the rough microstructure is developed by adding the nanoparticles in the organic binder material. To achieve smooth surface for the stable gap servo, some special techniques should be added, for example the solubility of the nanoparticles should be enhanced by the optimization of the surface of the nanoparticles.

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주기적 왕복유동에 의한 축열매체의 열회수 특성에 관한 연구 (A Study on Heat Recovery Characteristics of Porous Media According to Periodic Oscillating Flows)

  • 한화택;신민우
    • 설비공학논문집
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    • 제19권2호
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    • pp.175-182
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    • 2007
  • The objective of the present study is to investigate the heat storage characteristics of a packed bed according to periodically oscillating flows. Experiments have been performed to measure transient temperature distributions in solid and fluid Phases of the porous media. A simplified analytical model has been developed with intra-particle and dispersion effects neglected, and non-dimensional parameters have been derived. The transient temperature distributions according to the simplified numerical model agree well with the experimental results. Heat storage efficiencies defined in two different ways are obtained for various time periods and face velocities.

모바일 해시계 (Mobile Sundial)

  • 이유리;박지영;이강희
    • 한국컴퓨터정보학회:학술대회논문집
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    • 한국컴퓨터정보학회 2012년도 제46차 하계학술발표논문집 20권2호
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    • pp.303-304
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    • 2012
  • 본 눈문은 시각의 중요 수단으로 여겨지는 빛보다, 새로운 시각 표현 방법인 그림자에 초점을 맞추어 제작한 작품 에 대한 것으로 은 전통 시계인 해시계로부터 모티브를 얻었다. 이는 아두이노 보드(Arduino Board)와 SSR(Solid State Relay), 거리감지 센서, 220V 전구 등을 이용하여 제작했다. 이는 전구가 순차적으로 켜지면서 시계방향으로 그림자가 생기는 것을 작동 원리로 한다. 이 작품은 관객 참여를 바탕으로 하며 추후에 모바일 응용 분야로 발전될 가능성이 있다.

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Development of an improved selective media for differentiation of emetic and diarrheal type Bacillus cereus

  • Hong, Yong-Gun;Lee, Jin-Joo;Kim, Sang-Soon
    • 한국식품과학회지
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    • 제53권6호
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    • pp.815-818
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    • 2021
  • The objective of this study was to develop a differential medium with improved selectivity for the isolation of Bacillus cereus. Mannitol egg yolk polymyxin medium supplemented with D-galactose allowed the differentiation of diarrheal- and emetic-type B. cereus through pH monitoring. The pH of the medium decreased significantly when incubating the emetic-type B. cereus, whereas the pH change was not significant when incubating the diarrheal-type. The addition of pH indicators, such as methyl red and phenol red, to the medium allowed visual differentiation between diarrheal- and emetic-type B. cereus. A solid agar medium was also developed by optimizing the concentrations of medium components such as monosaccharides, agar, egg yolk enrichment, pH indicators, and antibiotics. This study indicates the possibility of applying selective media for the differentiation of diarrheal- and emetic-type B. cereus.

Enhanced Thermotolerance of Entomopathogenic Beauveria bassiana and Metarhizium anisopliae JEF-isolates by Substrate Modification

  • Yu, Jeong Seon;Lee, Se Jin;Shin, Tae Young;Kim, Woo Jin;Kim, Jae Su
    • International Journal of Industrial Entomology and Biomaterials
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    • 제41권2호
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    • pp.28-35
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    • 2020
  • Entomopathogenic Beauveria bassiana and Metarhizium anisopliae are well-known biological control agents worldwide, and have high potential in industrialization. However, their thermo-susceptibility limits long-term storage under high temperature conditions and insecticidal activity after application in target pests. The virulences of M. anisopliae JEF-003 and JEF-004, and B. bassiana JEF-006 and JEF-007 against bean bug (Riptortus pedestris), and the thermotolerance of conidia produced on three kinds of grains, sorghum, millet and Italian millet as substrates for solid cultures were investigated. Of the three grains, Italian millet was the suitable grains in the production of thermotolerant conidia, and a significant relationship between conidial thermotolerance and the media was demonstrated. This work suggests that biological characteristics of entomopathogenic fungi are altered by culture media, and these results will be a chance to understand the factors in the media which make such changes.

포화된 다공질 매체의 질량 보존과 운동량 보존에 대한 Arbitrary Lagrangian Eulerian(ALE) 정식화 (Formulation of Mass Conservation and Linear Momentum Conservation for Saturated Porous Media in Arbitrary Lagrangian Eulerian(ALE) Description)

  • 박대효;정소찬;김원철
    • 한국지반환경공학회 논문집
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    • 제4권1호
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    • pp.5-10
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    • 2003
  • 다공질 매체 속의 내부 구조를 이루고 있는 고체 부분과 유체 부분은 서로 다른 재료특성을 가지는 물체들로 구성되어 있고 각 구성물들은 서로 다른 물리적 성질과 화학적 성질을 가지면서 서로 다른 상대 속도를 가지고 이동하기 때문에 포화된 다공질 매체의 구조적 변형 거동을 해석하는 것은 매우 복잡하다. 변형 거동에 영향을 주는 여러 가지 복합적인 요인들이 고려된 다공질 매체의 변형 거동을 해석하고 규명하기 위하여 Arbitrary Lagrangian Eulerian(ALE) 정식화가 이루어진 구성방정식을 세워야 할 필요가 있다. ALE 정식화는 Lagrangian 요소와 Eulerian 요소의 장점을 최대화 시키고 단점을 최소화 시키는 것에 주안점을 두기 때문에 고체 부분과 유체 부분을 함께 고려해야 하는 다공질 매체의 변형 거동을 해석하는데 있어서 적합한 방법이라고 할 수 있다. 그렇기 때문에 여기서는 포화된 다공질 매체의 보존 법칙들에 대한 ALE 정식화가 이루어진다. 고체 부분과 유체 부분의 질량 보존 법칙에 대하여 ALE 정식화가 이루어진 식이 각각 표현되고 다공질 매체 전체에 대한 운동량 보존 법칙이 표현된다.

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