• Title/Summary/Keyword: Mie scattering

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Study on Spray Characteristics of Single-Hole GDI Injector according to Nozzle Hole Diameter - (1) Comparison of Injection and Macroscopic Spray Characteristics (노즐 홀 직경에 따른 단공 GDI 인젝터의 분무 특성 연구 - (1) 분사 및 거시적 분무특성 비교)

  • Park, Jeonghyun;Ro, Seungcheon;Chang, Mengzhao;Park, Suhan
    • Journal of ILASS-Korea
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    • v.25 no.4
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    • pp.145-153
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    • 2020
  • The purpose of this study is to compare the injection and spray characteristics of single-hole GDI injectors using injection rate and mie-scattering spray images. Five types of single-hole injectors with different nozzle hole diameters were used, and the spray rate, spray tip penetration, spray area, and spray width were analyzed. As a result, the diameter of the nozzle hole had a direct effect on the injection and spray characteristics. It was confirmed that the larger the diameter of the nozzle hole, the higher the injection quantity, the spray tip penetration, the spray area, and the spray width. In addition, it was confirmed that the near-field spray, which has little influence of ambient air, has a great correlation with the injection rate.

Spray and Atomization Characteristics of an Agricultural Nozzle by Changing the Injection Pressures (분사 압력 변화에 따른 농업용 노즐의 분무 및 미립화 특성)

  • Chang, Mengzhao;Park, Suhan
    • Journal of ILASS-Korea
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    • v.26 no.4
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    • pp.189-196
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    • 2021
  • Spray drift of agricultural nozzles has become a big issue because it causes low precision targeting and environmental pollution. In order to reduce the spray drift, study spray characteristics of agricultural nozzles is virtually important. In this study, shadowgraph and Mie-scattering visualization techniques were used to study the macroscopic spray and atomization characteristics of an agricultural nozzle. PDPA was used to measure the atomization characteristics of spray. The injection pressure is set to 1 bar, 3 bar and 5 bar, which covers the working range of the nozzle. For the PDPA experiment, 75 points were measured in an area of 160 mm × 120 mm at 10 mm intervals directly below the nozzle to grasp the overall atomization characteristics of the spray. It was found that the spray width and sheet width showed a linear correlation. As the injection pressure increased, the sheet expansion in the 0-degree direction and the sheet swing in the 90-degree direction jointly promoted the breakup of the sheet. In addition, the area close to the central axis had a large droplet velocity, and since a large droplet velocity promoted atomization of spray, the area close to the central axis had a smaller spray droplet diameter than the left and right regions.

The Measurement of the Temperature Variation in a Constant Volume Combustion Chamber by the Laser Rayleigh Scattering (레이저 레일레이 산란법에 의한 定積燃燒室內의 溫度變動에 대한 計測)

  • ;;苦井和憲;志水昭史
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.328-340
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    • 1991
  • The combustion process in the combustion chamber has been investigated by taking pressure, temperature, chemical equilibrium and the shape of flame. To predict temperature of a flame in a combustion chamber is one of very important problems in the field of combustion and the temperature is a important factor of ignition and counteraction to inflammation. In this paper, the flame temperature was determined by the method of the Rayleigh scattering of Ar-Ion Laser (514.5nm). The Rayleigh scattering has been got considerably attention because of its strong cattering intensity. As a result, it is shown that I can measure the shape of flame by schlieren photography and that I can get the flame temperature variation in constant volume combustion chamber by Laser Rayleigh Scattering.

Effect of Wavelength-dependent Scattering on the Color Chromaticity of the LCD Backlight

  • Kwon, Jin Hyuk;Jun, Hwa Joon;Gwag, Jin Seog;Lee, Hong Su
    • Journal of the Optical Society of Korea
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    • v.17 no.3
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    • pp.275-278
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    • 2013
  • The effect of the wavelength-dependent scattering on the change of the color chromaticity in the lightguide panel of a liquid crystal display is examined. The white light emitted from the white LEDs located at the edge of the lightguide propagates in the lightguide and is scattered by the patterned dots that are placed on the bottom of the lightguide. The scattered lights that are far from the LEDs showed reddish color compared to the bluish color that is scattered from the near area from the LEDs. The color difference was between 0.01 to 0.06 depending on the resin and the thickness of the lightguide.

Rapid detection microfluidic immunosensor for food safety using static light scattering

  • Kim, Kee-Sung
    • 한국환경농학회:학술대회논문집
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    • 2009.07a
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    • pp.187-199
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    • 2009
  • We present real.time, rapid detection of Mycoplasma pneumonia in phosphate buffered saline (PBS) inside a Y.channel polydimethylsiloxane (PDMS) microfluidic device by means of optical fiber monitoring of latex immunoagglutination. The latex immunoagglutination assay was performed with serially diluted Mycoplasma pneumonia solutions using highly carboxylated polystyrene particles of 390nm and 500nm diameter conjugated with monoclonal anti. Mycoplasma pneumonia . Proximity optical fibers were located around the viewing cell of the device, which were used to measure the increase in 45${\b{o}}$ forward light scattering of the immunoagglutinated particles. The detection limit was less than 50 $pgml^{-1}$ both for 390nm and 500nm microspheres with the detection time less than 90 seconds.

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Effect of Silver Nanoparticles with Indium Tin Oxide Thin Layers on Silicon Solar Cells

  • Oh, Gyujin;Kim, Eun Kyu
    • Applied Science and Convergence Technology
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    • v.26 no.4
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    • pp.91-94
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    • 2017
  • AThe effect of localized surface plasmon on silicon substrates was studied using silver nanoparticles. The nanoparticles were formed by self-arrangement through the surface energy using rapid thermal annealing (RTA) technique after the thin nanolayer of silver was deposited by thermal evaporation. By the theoretical calculation based on Mie scattering and dielectric function of air, indium tin oxide (ITO), and silver, the strong peak of scattering cross section of silver nanoparticles was found at 358 nm for air, and 460 nm for ITO, respectively. Accordingly, the strong suppression of reflectance under the condition of induced light of $30^{\circ}$ occurred at the specific wavelength which is almost in accordance with peak of scattering cross section. When the external quantum efficiency was measured using silicon solar cells with silver nanoparticles, there was small enhancement peak near the 460 nm wavelength in which the light was resonated between silver nanoparticles and ITO.

An Experimental Study of Silica Particle Growth in a Coflow Diffusion Flame Utilizing Light Scattering and Local Sampling Technique (I) - Effects of Flame Temperature - (광산란과 입자포집을 이용한 동축류 확산화염 내의 실리카 입자의 성장 측정(I) - 화염온도의 영향 -)

  • Cho, Jaegeol;Lee, Jeonghoon;Kim, Hyun Woo;Choi, Mansoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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    • pp.1139-1150
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    • 1999
  • The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

Analysis of the Scattering Property of Dielectric Scatterer with Impedance Boundary Condition (임피던스 경계면 조건을 적용한 유전체의 산란 특성 분석)

  • Hwang, Ji-Hwan;Park, Sin-Myeong;Oh, Yisok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.10
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    • pp.1087-1094
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    • 2014
  • An numerical technique of impedance boundary condition to improve an efficiency in the process of moment method with CFIE(Combined Field Integral Equation), which is widely used to analyze the scattering property of dielectric scatterers, and results of its cross-validations are presented in this study. Application of the impedance boundary allows to represent the equivalent surface currents of dielectric scatterer depicted by both kinds of electric/magnetic surface currents(Js, Ms) to the single surface current by Js or Ms only. Accuracy of this technique is validated by the existing CFIE and theoretical values such as Mie-series solution and small perturbation scattering model. The computational difference of less than 1 dB was verified within an imaginary part of dielectric constant more than 12, as well.

The Characteristics of Unconfined Hydrogen Diffusion Flames in Supersonic Air Flows (초음속 공기 유동장에서의 수소 확산 화염 특성에 대한 연구)

  • 김제흥;심재헌;김지호;윤영빈
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.4
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    • pp.78-86
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    • 2000
  • The objective of this research is to understand the characteristics of a nonpremixed, turbulent, hydrogen jet flame which is stabilized in Mach 1.8 coflowing air flows. In order to investigate the flame structure, flame lengths and fuel trajectories were measured by using direct photography, acetone PLIF, Mie scattering techniques, and numerical simulation. Effect of increasing air velocity was investigated when fuel velocity is fixed. The subsonic flame length was decreased drastically, however the supersonic flame length was increased slowly Then the change of flame blow out characteristics was observed as varying fuel nozzle lip thickness. The flame stability can be increased when fuel nozzle lip thickness was increased, which indicates that the minimum fuel lip thickness ratio is required for the stable supersonic flames. Also, it is found that fuel jet is blocked by high pressure zone and low scattering zone is made. Then the fuel that was moving along the recirculation zone had longer residence time within the supersonic flames, which made partially premixed zone.

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Theoretical Analysis of the Lock-on Range of a Man-portable Air Defense System Under Foggy Conditions with the Radiative-transfer Equation (복사전달방정식을 활용한 안개 조건에서의 휴대용 대공 유도미사일 Lock-on range에 대한 이론적 분석)

  • Seok, In Cheol;Lee, Chang Min;Hahn, Jae W.
    • Korean Journal of Optics and Photonics
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    • v.30 no.1
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    • pp.1-7
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    • 2019
  • MANPADS (man-portable air defense system) is a counterweapon system against enemy aircraft, tracking the MWIR (mid-wavelength of infrared) signature of the plume. Under foggy conditions, however, multiple scattering phenomenon caused by the particles affects the MWIR transmittance, and the MANPADS detection performance. Therefore, in this study we analyzed the lock-on range of MANPADS with varying fog conditions and plume characteristics. To analyze the optical extinction properties and transmittance in fog, Mie scattering theory and analytic solution of the radiative-transfer equation are utilized. In addition, we used flare signature as an alternative MWIR light source. We confirmed that the lock-on range could be noticeably reduced under conditions of mist, and proportional to the flare temperature.