• Title/Summary/Keyword: Light Diffusion

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A Study on chemiluminescence characteristics of a turbulent flame for different measurement location (난류 확산화염의 계측 위치에 따른 화염자발광 특성에 대한 연구)

  • Kwon, Minjun;Lee, Changyeop;Kim, Sewon
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.219-222
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    • 2014
  • The flame chemiluminescence is a good tracer of flame statement. In this study, the characteristics of flame chemiluminescence($OH^*$, $CH^*$, ${C_2}^*$) according different measuring locations using photomultiplier(PMT), spectrometer and CCD camera. Measurements are made for $OH^*$, $CH^*$, ${C_2}^*$ radicals in gas & light oil diffusion flames. At turbulent nonpremixed combustion mode, the equivalence ratio is varied. The experimental results showed that measuring location affects the result of flame chemiluminescence.

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Experimental Study on Brownian Coagulation in the Transition Regime (전이영역에서의 Brown 응집에 관한 실험적 연구)

  • Kim Dae-Seong;Lee Gyu-Won
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2003.05b
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    • pp.355-356
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    • 2003
  • Coagulation is a process whereby particles collide with one another due to their relative motion, and adhere to form large particles. Coagulation caused by the random Brownian motion of particles is called Brownian coagulation. Many properties, such as light scattering, electrostatic charges, toxicity, as well as physical processes, including diffusion, condensation and thermophoresis depend strongly on their size distribution. Therefore, Brownian coagulation is substantially important in atmospheric science, combustion technology, inhalation toxicology and nuclear safety analysis. (omitted)

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A Review on Fluorescent Lamps Having Noncircular Cross-sections

  • Ko, Jae-Hyeon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1165-1168
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    • 2005
  • We review discharge characteristics of fluorescent lamps having noncircular cross sections. The developmental and theoretical history of noncircular cross-section lamps is summarized chronologically. In particular, discharge characteristics of noncircular cross-section lamps will be summarized and analyzed including plasma contraction, electron temperature, and ambipolar diffusion loss, which might give us some insights into the way to develop more efficient and uniform flat fluorescent lamps, which have recently arisen as a new light source of large-size backlight units for LCD TV applications.

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Development of Aerosol Model Using Moment Method and Validation by Experiments (모멘트 방법을 이용한 에어로즐 모델의 개발과 실험을 통한 검증)

  • Kim Gyeong-A;Kim Dae-Seong;Park Seong-Hun;Gwon Sun-Park;Lee Gyu-Won
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.11a
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    • pp.385-386
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    • 2002
  • Many important physical properties of natural or man-made aerosol particles such as light scattering, electrostatics charges, and toxicity, as well as their behavior involving physical processes like diffusion and thermophoresis depend strongly on their size distribution. Important aerosol behavior mechanisms affecting the size distribution of aerosol particles include condensation, deposition, and coagulation. (omitted)

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Cn-PSEUDO ALMOST AUTOMORPHIC SOLUTIONS OF CLASS r IN THE 𝛼-NORM UNDER THE LIGHT OF MEASURE THEORY

  • DJENDODE MBAINADJI
    • Journal of Applied and Pure Mathematics
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    • v.6 no.1_2
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    • pp.71-96
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    • 2024
  • In this paper we present many interesting results such as completeness and composition theorems in the 𝛼 norm. Moreover, under some conditions, we establish the existence and uniqueness of Cn-(𝜇, 𝜈) pseudo-almost automorphic solutions of class r in the 𝛼-norm for some partial functional differential equations in Banach space when the delay is distributed. An example is given to illustrate our results.

A Study on the Characteristic of Dye-sensitized Solar Cell by Controlling the Roughness Factor of Counter Electrode (염료감응형 태양전지의 상대전극 Roughness Factor 조절을 통한 셀 특성 연구)

  • Son, Min-Kyu;Seo, Hyun-Woong;Lee, Kyoung-Jun;Kim, Jeong-Hoon;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.428-430
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    • 2008
  • Dye-sensitized solar cell has many internal resistant components such as Pt counter electrode, $TiO_2$/dye/electrolyte, charge diffusion, sheet resistance of TCO. Among these, the resistance about the counter electrode can be reduced by increasing the roughness factor of Pt counter electrode. This causes the increase of fill factor and improvement of efficiency. And the amount of light reflection on the counter electrode also increases as the roughness factor goes up. In our experiment, we suggest a new deposition structure of Pt thin film that is a stepped-type structure. The more step lines are in the counter electrode, the more roughness factor is. As a result, we get the improvement of fill factor and efficiency by controlling the roughness factor of counter electrode.

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Basic Study on Combustion Characteristics of Coaxial Premixed Burner with the Addition of $Al_2O_3$ Particles (산화 알루미나 입자 첨가에 따른 동축류 예혼합 연소기의 연소 특성 기초연구)

  • Park, Seung-Il;Kim, Go-Tae;Kim, Nam-Il
    • Journal of the Korean Society of Combustion
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    • v.16 no.1
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    • pp.58-65
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    • 2011
  • Thermal spray technology has been used in many industrial application. Especially, thermal spray coating have been employed with the purposes of achieving better resistances in abrasion, heat and corrosion. In the previous studies on the thermal spray coating, thermal spray characteristics from the perspective of combustion engineering have not been investigated sufficiently, while the material characteristics of the coated substrates have been investigated widely. In this study, the effect of spray particles on the flame behavior was experimentally investigated. The amount of the injected particles was measured using the light scattering method and the temperature of the particles was estimated using a two-color method. Various flame-spray interactions were observed and it was found that the high temperature zone near the flame is elongated by particles density. Based on these results, the applicability of the light scattering method and the two-color method was discussed.

Preparation and Characterization of Blue-Emitting Polymer/Dielectric Nanolayer Nanocomposites (청색발광 고분자/절연 나노층 나노 복합체의 제조 및 특성화)

  • 박종혁;박오옥;김재경;유재웅;김영철
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.7-10
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    • 2003
  • Blue-light-emitting peiymer/dielectric nanolayer nanocomposites were prepared by the solution intercalation method and employed in electroluminescent device. Their photoluminescence and electroluminescence characteristics suggested that the nanolayers isolate the polymer chains and hinder the formation of excimers and aggregates. By reducing the excimer formation and its deleterious effects on emission efficiency, both the color purity and the luminescence stability were improved. Furthermore, the dielectric nanolayers have an aspect ratio of about 500 and therefore act as efficient barriers to oxygen and moisture diffusion, which produced a dramatic increase in the device stability.

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Synthesis of titania nanopowder and its photocatalytic properties

  • Jang, Hee-Dong;Lee, Jae-Chun;Kil, Dae-Sup
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.569-572
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    • 2003
  • Titanium dioxide ($TiO_2$) nanoparticles were prepared by the oxidation of titanium tetrachloride ($TiCl_4$) in a diffusion flame reactor. The average diameter of particles was 15 to 30 nm and mass fraction of anatase ranged from $40\;to\;80\%$. Effects of particle size and phase composition of those $TiO_2$ nanoparticles on photocatalytic properties such as decomposition of methylene blue and bacteria gas were investigated. The degree of decomposition of methylene blue by the $TiO_2$ nanoparticles under the illumination of the black light was directly proportional to the anantase mass fraction, but inversely to the particle size. The decomposition of bacteria by the $TiO_2$ nanoparticles under the illumination of the fluorescent light showed the same trend as in the case of the methylene blue.

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