• Title, Summary, Keyword: scattering

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Bistatic Scattering from a Hemi-Spherically Capped Cylinder

  • Park, Sang-Hyun;La, Hyoung-Sul;Cho, Sung-Ho;Oh, Taek-Hwan;Kim, Young-Shin;Lee, Chang-Won;Na, Jung-Yul
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.3E
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    • pp.115-122
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    • 2006
  • The bistatic scattering of an incident wave by a hemi-spherically capped cylinder is of particular interest because it has rarely been studied until the present day. The configuration of a hemi-spherically capped cylinder is similar to naval underwater weapons (submarines, mines, torpedos, etc.), but which is not exactly the same. This paper describes a novel laboratory experiment aimed at direct measurement of bistatic scattering by a hemi-spherically capped cylinder. Bistatic scattering by a hemi-spherically capped cylinder was measured in an acoustic water tank (5m long, 5m wide, 5m deep) using a high frequency projector (120kHz) and hydrophone. Measurements of monostatic scattering were also made under the same conditions. The bistatic scattering pattern by a hemi-spherically capped cylinder was measured against the incident angles $(0^{\circ},\;15^{\circ},\;20^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;90^{\circ})$ in order to verify various scattering pattern characteristics by the change of incident angle. The results indicate that the bistatic scattering TS at a wide scattering angle is much stronger than the mono static scattering TS. In bistatic scattering, the forward scattering TS is significantly stronger than the backward scattering TS, and the forward scattering pattern is also broader. In case of seven incident angles, the maximum value of forward scattering TS is about 14dB stronger than that of backward scattering TS. It is also found that forward scattering varies with the incident angle of sound to a much less extent than backscattering, and it is not seriously affected by the incident angle. These features could be the advantages of using forward scattering for detecting underwater targets at long range and increasing detection area and probability.

Study on Analysis of Optical Deflection of Laser Scattering Based on Rayleigh Criterion for Crystalline Silicon Wafer in Solar Cell (태양전지용 결정질 실리콘 웨이퍼에서의 레일리기준 기반 레이저산란의 광편향 분석에 관한 연구)

  • Kim, Gyung-Bum
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.4
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    • pp.31-37
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    • 2010
  • In this paper, optical deflection of laser scattering has been investigated based on Rayleigh criterion for crystalline silicon wafer in solar cell. A laser scattering mechanism is newly designed using light scattering properties in silicon wafer. Intensity distributions of laser scattering are different, depending on the incident angle of laser computed from Rayleigh criterion. In case of the incident angle satisfied with the criterion, they are asymmetric. Also, their specular reflection angle is shifted to unpredicted ones. These phenomena are in accordance with previous theories of laser scattering. The optical deflection of laser scattering is experimentally identified with the designed laser scattering mechanism. Its mathematical model is presented from the geometric relationship of laser scattering. It is shown that the optical deflection of laser scattering agree with the presented model, exclusive of grazing angles which is satisfied with Rayleigh criterion.

A General Radar Scattering Model for Earth Surfaces

  • Jung, Goo-Jun;Lee, Sung-Hwa;Oh, Yi-Sok
    • Proceedings of the KSRS Conference
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    • pp.41-43
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    • 2003
  • A radar scattering model is developed based on an empirical rough surface scattering model, the radiative transfer model (RTM), a numerical simulation algorithm of radar scattering from particles, and experimental data obtained by ground-based scatterometers and SAR systems. At first, the scattering matrices of scattering particles such as a leaf, a branch, and a trunk, have been modeled using the physical optics (PO) model and the numerical full-wave analysis. Then, radar scattering from a group of mixed particles has been modeled using the RTM, which leads to a general scattering model for earth surfaces. Finally, the scattering model has been verified with the experimental data obtained by scatterometers and SAR systems.

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Investigation of Laser Scattering Pattern and Defect Detection Based on Rayleigh Criterion for Crystalline Silicon Wafer Used in Solar Cell (태양전지 실리콘 웨이퍼에서의 레일리기준 기반 레이저산란 패턴 분석 및 결함 검출)

  • Yean, Jeong-Seung;Kim, Gyung-Bum
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.5
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    • pp.606-613
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    • 2011
  • In this paper, patterns of laser scattering and detection of micro defects have been investigated based on Rayleigh criterion for silicon wafer in solar cell. Also, a new laser scattering mechanism is designed using characteristics of light scattering against silicon wafer surfaces. Its parameters are to be optimally selected to obtain effective and featured patterns of laser scattering. The optimal parametric ranges of laser scattering are determined using the mean intensity of laser scattering. Scattering patterns of micro defects are investigated at the extracted parameter region. Among a lot of pattern features, both maximum connected area and number of connected component in patterns of laser scattering are regarded as the important information for detecting micro defects. Their usefulness is verified in the experiment.

Finite-Difference Time-Domain Calculation of Light Scattering Efficiency for Ag Nanorings (유한차분 시간영역 방법을 이용한 Ag 나노링 구조의 산란효과)

  • Lee, Tae-Soo;Jeong, Jong-Ryul
    • Korean Journal of Materials Research
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    • v.22 no.10
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    • pp.519-525
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    • 2012
  • Enhancement of light trapping in solar cells is becoming increasingly urgent for the development of next generation thin film solar cells. One of the possible candidates for increasing light trapping in thin film solar cells that has emerged recently is the use of scattering from metallic nanostructures. In this study, we have investigated the effects of the geometric parameters of Ag nanorings on the light scattering efficiency by using three dimensional Finite Different Time Domain (FDTD) calculations. We have found that the forward scattering of incident radiation from Ag nanorings strongly depends on the geometric parameters of the nanostructures such as diameter, height, etc. The forward scattering to substrate direction is increased as the outer diameter and height of the nanorings decrease. In particular, for nanorings larger than 200 nm, the inner diameter of Ag nanorings should be optimized to enhance the forward scattering efficiency. Light absorption and scattering efficiency calculations for the various nanoring arrays revealed that the periodicity of nanorings arrays also plays an important role in the absorption and the scattering efficiency enhancement. Light scattering efficiency calculations for nanoring arrays also revealed that enhancement of scattering efficiency could be utilized to enhance the light absorption through the forward scattering mechanism.

A Theory of Scalar Wave Scattering by a Cylinder Buried in a Planar Substrate

  • Kim, Jin Seung
    • Journal of the Korean Physical Society
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    • v.70 no.8
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    • pp.771-776
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    • 2017
  • The problem of scalar wave scattering by a cylinder buried in a planar substrate is analytically solved. The solution is in the form of a coupled set of linear equations relating the coefficients of reflection and transmission of the planar substrate and those of scattering and transmission of the cylinder. The coupling is due to the process of multiple scattering by the two objects. Iterative substitution gives the solution in the form of a set of infinite series, and each term explicitly shows the effect of multiple scattering of increasing order.

A Theory of Scalar Wave Scattering by a Circular Cylinder and a Planar Substrate

  • Kim, Jin Seung
    • Journal of the Korean Physical Society
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    • v.70 no.6
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    • pp.574-579
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    • 2017
  • The problem of scalar wave scattering by a cylinder on or near a planar substrate is analytically solved. The solution is in the form of a coupled set of linear equations relating the coefficients of scattering and transmission of the cylinder and those of reflection and transmission of the planar substrate. The coupling is due to the process of multiple scattering by the two objects. Iterative substitution gives the solution in the form of a set of infinite series, and each term explicitly shows the effect of multiple scattering of increasing order.

Evaluation on Light Scattering Behavior of a Pulverized Coal Suspension (슬러리내 석탄입자의 광산란 특성 평가)

  • Hwang, Munkyeong;Nam, Hyunsoo;Kim, Kyubo;Song, Juhun
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.5
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    • pp.451-460
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    • 2013
  • In a direct coal fuel cell (DCFC) system, it is essential to identify volume fraction of coal suspended in electrolyte melt in order to control its dispersion and fluidity. This requirement is compelling especially at anode channel where hot slurry is likely to flow at low velocity. In this study, light scattering techniques were employed to measure the volume fraction for a pulverized coal suspension with relatively high absorption coefficient. The particle size, scattering angle, and volume fraction were varied to evaluate their effects on the scattering behavior as well as scattering regime. The larger coal size and smaller forward scattering angle could provide a shift to more favorable scattering regime, i.e., independent scattering, where interferences of light scattering from one particle with others are suppressed.

Mumerical Anlysis of light Scattering Patterns for Measurement of Roughmess(I) (표면 거칠기 광산란 패턴의 컴퓨터 수치 분석 (I))

  • 임동열;김승우
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.2
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    • pp.267-280
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    • 1992
  • This paper describes a numerical analysis of the light scattering patterns of roughness profiles. This analysis was based upon the light scattering theory developed by Beckmann. In the analysis, the roughness profile was regarded as a profile whose irregularities depend on the production process and the shape of cutting tool. Generally, waviness of an actual surface seriously distorts the scattered pattern of roughness profile. In order to avoid the effects of waviness of actual surfaces, several theoretically calculated scattering patterns, instead of actual scattering patterns, were used to analyze the scattering patterns of typical engineering roughness profiles. The characteristics of the light scattering patterns for five model surfaces were studied.

THE STUDY OF SCATTERING IN THE ISM WITH HIGH RESOLUTION OBSERVATIONS OF OH MASERS

  • Migenes, Victor;Slysh, V.I.;Velasco, A.E.Ruis;Villalpando, S.
    • Journal of The Korean Astronomical Society
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    • v.40 no.4
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    • pp.131-132
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    • 2007
  • The research of OH maser emission sources with high angular resolution is complicated by the effects of interstellar scattering: more over, most of the OH maser sources are located in the galactic plane where the scattering is largest. However, the data available from pulsar studies on the spatial distribution of the amount of scattering indicate that there is a strong non-uniformity in the distribution of the amount of scattering material. There are directions in the galactic plane where the scattering is an order of magnitude higher than the average, as well as directions where the scattering is much lower. The latter provide an opportunity to investigate OH masers with the full angular resolution offered by very long baseline interferometry instruments, like the VLBA, and measure their true angular size, shape and brightness temperature. We have observed approximately 100 OH maser sources, distributed all over the northern hemisphere, with the VLBA in order to study the scattering properties of the interstellar medium.