• 제목/요약/키워드: Light scattering coefficient

검색결과 76건 처리시간 0.027초

서울 대기 Aerosol의 물리적 특성 : 가시광선의 산란 (Physical Characteristics of Atmospheric Aerosols in Seoul : Scattering of Visible Light)

  • 김필수
    • 한국대기환경학회지
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    • 제4권2호
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    • pp.28-37
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    • 1988
  • Light scattering coefficient of visible light by atmospheric aerosol over the size range 0.01-10$\mu$m is determined from scattering efficiency and aerosol size distribution. Aerosol number distribution as a function of particle diameter dN/dlog D decreases rapidly as increasing particle size. Distribution of scattering coefficient d$\sigma_s/dlog$ D is mostly accumulated in diameter 0.1-2.0 $\mu$m showing its maximum in the vicinity of 0.6$\mu$m. This means that the visible light in the atmosphere is mainly scattered by these particles. Diurnal variation of scattering coefficient $\sigma_s$ appears its maximum in the morning, while minimum in the afternoon which agrees with the aerosol number distribution in the size range 0.1-2.0 $\mu$m.

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시간 분해 반사율 측정에 의한 다중산란 매질의 광학 계수 측정 (Measurements of Optical Constants of Biomedical Media Based on Time-Resolved Reflectance)

  • 전계진;박승한;김웅;윤길원;김원기
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1996년도 춘계학술대회
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    • pp.235-239
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    • 1996
  • In recent years, the optical properties of multiple-scattering media like tissue have been studied for their potential applications in medicine. In this work the optical properties of multiple scattering media were investigated using the time-resolved reflectance measurement. The reflected light was measured by time-correlated single photon counting system. The transport scattering and absorption coefficient are related to the initial rapid decay and the subsequent decay in reflected light, respectively. Also the optical properties of the samples were measured by conventional method, ie., using continuous wave light. When the distance between the light source and the detector is over 8mm, the optical coefficient can be measured accurately using the suggested method.

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

  • 황문경;남현수;김규보;송주헌
    • 한국수소및신에너지학회논문집
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    • 제24권5호
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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.

Persistence length calculation from light scattering and intrinsic viscosity of dilute semiflexible polyimide solutions with different degree of imidization

  • Hansol Cho;Kim, Youn-Cheol;Kim, Sang-Ouk;Chung, In-Jae
    • Korea-Australia Rheology Journal
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    • 제12권1호
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    • pp.69-76
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    • 2000
  • We have derived the translation diffusion coefficient and the intrinsic viscosity formula adopting the Kholodenko's theory using 3+1 dimensional Dirac propagator in the Kirkwood and Riseman scheme. We also performed static light scattering experiments and intrinsic viscosity measurement of dilute solutions of polyimides with different rigidities. In the framework of Kholodenko's theory, we can easily measure the persistence length of polyimide. We prepared five different polyamic acids and polyimides with different degree of imidization by controlling imidization temperatures. From experimental results, we obtained molecular weights and persistence lengths according to the Kholodenko's plot. The molecular weight and the intrinsic viscosity decreased and then increased with the imidization temperature but the persistence length increased monotonically and then leveled off. The persistence lengths calculated from intrinsic viscosities showed very good agreement with those from light scattering experiments.

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무질서한 매질에서 침투깊이와 파동 전파 (Penetration depth and Wave Propagation in Random Media)

  • 김기준;성기천
    • 한국응용과학기술학회지
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    • 제23권1호
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    • pp.70-76
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    • 2006
  • The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.

제지 원료의 특성 및 물리적 처리가 종이의 기공 구조 및 물성에 미치는 영향 (Effects of Raw Materials for Papermaking and Physical Treatment on the Pore Structure and Paper Properties)

  • 원종명;남기영;정순기
    • 펄프종이기술
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    • 제39권4호
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    • pp.7-13
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    • 2007
  • Effects of pulp type, refining and filler type on the pore characteristics and physical properties of paper were investigated. HwBKP, SwBKP and BCTMP are used to study the effect of pulp type in this study. The effects of each filler (PCC, GCC and talc) and the combination of PCC/GCC were also studied. Highest bulk, pore volume and light scattering are obtained from BCTMP and PCC. It was found that the pore size and pore volume are important in light scattering in paper structure. It was found that PCC was the most effective filler for the improvement of the bulk and light scattering because of the increase in pore volume which can scatter light, but the increase of PCC content was not so effective in the improvement of bulk.

혼탁 매질에서 광산란에 의한 광학적 파라미터들의 측정에 관한 연구 (Studies on the Measurements of Optical Parameters in Turbid Material by Light Scattering)

  • 김기준;성기천
    • 한국응용과학기술학회지
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    • 제12권2호
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    • pp.151-156
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    • 1995
  • The influences of fluorophor, scatterer, absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it has been studied the molecular properties by laser induced fluorescence spectroscopy. It has been found that the effects of optical properties in scattering media by the optical parameters(${\mu}_{s}$, ${\mu}_{a}$, ${\mu}_{t}$). The value of scattering coefficient ${\mu}_{s}$ is large by means of the increasing particles of scatterer, it has been found that the slope decays exponentially as a function of distance from laser source to detector. It may also aid in designing the best model for oil chemistry, laser medicine and application of medical engineering.

농도가 진한 매질에서 광증감제에 의한 광학적 파라미터측정에 관한 연구 (A Study on the Measurements of Optical Parameters in Photosensitizer by Light Scattering)

  • 김기준;이주엽
    • 한국응용과학기술학회지
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    • 제28권1호
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    • pp.102-108
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    • 2011
  • The study of wave propagation and scattering in biological media has become increasingly important in recent years. The propagation of light within tissues is an important problem that confronts the dosimetry of therapeutic laser delivery and the development of diagnostic spectroscopy. In the clinical application of photodynamic therapy(PDT) and in photobiology, the photon deposition within a tissue determines the spatial distribution of photochemical reactions. Scattered light is measured as a function of the distance (r) between the axis of the incident beam and the detection spot. Consequently, knowledge of the photosensitizer(Chlorophyll-a) function that characterizes a phantom is measured. To obtain the results of scattering coefficients(${\mu}s$) of a turbid material from diffusion described by experimental approach. It was measured the energy fluency of photon radiation at the position of penetration depth. From fluorescence experimental method obtained the analytical expression for the scattered light as the values of $(I/I_o)_{wavelength}$ vs the distance between the center of the incident beam and optical fiber in terms of the condition of "in situ spectroscopy(optically thick)" and real time by fluorometric measurements. The result was compromised with transport of intensities though a random distribution of scatters.

주파수 영역 확산광 단층촬영 장치를 이용한 광 팬텀 및 인체조직의 광 계수 측정 (Optical Property Measurements of Optical Phantoms and Honan Tissues Using Frequency-Domain Diffuse Optical Tomography)

  • 호동수;권기운;엄기윤;이승덕;김법민
    • 대한의용생체공학회:의공학회지
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    • 제28권2호
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    • pp.229-234
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    • 2007
  • Diffuse optical tomography (DOT) is a relatively new medical imaging modality which uses near infrared light to image large-sized tissues noninvasively. We constructed a frequency-domain DOT system to measure the optical properties of optical phantoms and human tissues. The FD-DOT uses the intensity-modulated infrared light source that illuminates the biological tissues. The phase shift and modulation changes at each detector site are separately processed to measure the optical properties. The absorption and scattering coefficients are separately estimated using inverse algorithms.

고해부하가 종이의 물성에 미치는 영향 (The Effect of Refining Load on the Paper Properties)

  • 김용식;원종명
    • 펄프종이기술
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    • 제33권1호
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    • pp.38-44
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    • 2001
  • The effects of refining load on the paper properties were investigated. HwBKP, SwBKP and SwUKP were refined with PFI mill at the load of 3.33 N/mm and 6.00 N/mm. Higher Scott bond was obtained at the higher refining load for three pulp used in this study. However any changes in the light scattering coefficient with the change of refining load were not observed. Although the effect of refining load on the formation index for SwUKP was not observed, higher refining load gave the better formation for HwBKP and SwBKP. The fiber mass and fiber crowding factor were not affected by the refining load. Higher apparent density and tensile index were obtained with the higher refining load. However, the higher refining load did not improve the tensile index at the same apparent density. The tear index was decreased with the increase of refining load.

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