Artykuły w czasopismach: „Scattering coefficient”

1

Zhang, Q. Q., X. J. Wu, C. Wang, S. W. Zhu, Y. L. Wang, Bruce Z. Gao i X. C. Yuan. "Scattering Coefficients of Mice Organs Categorized Pathologically by Spectral Domain Optical Coherence Tomography". BioMed Research International 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/471082.

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Differences in tissue density cause a variety of scattering coefficients. To quantify optical coherence tomography (OCT) images for diagnosis, the tissue's scattering coefficient is estimated by curve fitting the OCT signals to a confocal single backscattering mode. The results from a group of 30 mice show that the scattering coefficients of bone, skin, liver, brain, testis, and spleen can be categorized into three groups: a scattering coefficient between 1.947 and 2.134 mm−1: bone and skin; a scattering coefficient between 1.303 and 1.461 mm−1: liver and brain; a scattering coefficient between 0.523 and 0.634 mm−1: testis and spleen. The results indicate that the scattering coefficient is tissue specific and could be used in tissue diagnosis.

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KÖRKKÖ, MIKA, OSSI LAITINEN, ANTTI HAAPALA, ARI ÄMMÄLÄ i JOUKO NIINIMÄKI. "Scattering properties of recycled pulp at the near infrared region and its effect on the determination of residual ink". June 2011 10, nr 6 (1.07.2011): 17–22. http://dx.doi.org/10.32964/tj10.6.17.

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Residual ink in recycled pulp can be determined from a wide variety of pads and sheets using either a constant or measured near infrared (NIR) scattering coefficient. The method is usually chosen on the basis of the opaqueness of the prepared test media. Although both methods are regularly used, it is unclear whether NIR scattering properties of pulp vary due to changing proportions of fibers and fines and whether the changing NIR scattering coefficient affects the residual ink values. We investigated the effect of varying scattering coefficient on residual ink results obtained with unknown (constant) and known (measured) NIR scattering coefficients. We measured the NIR scattering coefficients and residual ink values (using the wavelength of 700 nm) from low-grammage sheets with deliberately varied filler content. By varying the filler content, changes were detected in the NIR scattering properties of pulp; therefore, the residual ink values were biased when a constant scattering coefficient was used. However, when the scattering coefficient was measured during the determination of residual ink, no deviation was observed when compared with the values calculated according to mass proportions. The measured NIR scattering coefficient should always be used during the determination of residual ink values.

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3

Sato, Haruo. "Isotropic scattering coefficient of the solid earth". Geophysical Journal International 218, nr 3 (6.06.2019): 2079–88. http://dx.doi.org/10.1093/gji/ggz266.

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SUMMARY The isotropic scattering model is a simple mathematical model of the radiative transfer theory (RTT) for the propagation of the wave energy density in random media. There have been many measurements of the isotropic scattering coefficient of the heterogeneous solid earth medium, where the target region varies from the lower and upper mantle, the crust, sediments, volcanoes, mines, rock samples and also the crust and the upper mantle of the moon. Reported isotropic scattering coefficients increase according to some power of frequency with some scatter. We know that the RTT is well approximated by the diffusion equation in the multiple scattering regime, where the equipartition is established. Then, the transport scattering coefficient effectively functions as an isotropic scattering coefficient even if the scattering coefficient derived by the Born approximation for the random velocity fluctuation is anisotropic. Recent review of the power spectral density functions of random velocity fluctuations in the solid earth revealed from various kinds of measurements shows that their spectral envelope is well approximated by the inverse cube of wavenumber for a wide range of wavenumbers (Sato, 2019). The transport scattering coefficient derived from the spectral envelope linearly increases with frequency, which well explains the observed isotropic scattering coefficients for a wide range of frequencies. However, some reported isotropic scattering coefficients show unusual behaviour: the isotropic scattering coefficient increases as depth decreases in the crust and the upper mantle of the earth and the moon, those beneath volcanoes are larger than those in the lithosphere, and that in a sandstone sample with a large porosity is larger than that in a gabbro sample with little porosity. Those differences may suggest possible scattering contribution of pores and cracks widely distributed in addition to the scattering by random velocity fluctuations.

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Chung, Won Young, Sun Young Kim i Chang Ho Kang. "Image Dehazing Using LiDAR Generated Grayscale Depth Prior". Sensors 22, nr 3 (5.02.2022): 1199. http://dx.doi.org/10.3390/s22031199.

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In this paper, the dehazing algorithm is proposed using a one-channel grayscale depth image generated from a LiDAR point cloud 2D projection image. In depth image-based dehazing, the estimation of the scattering coefficient is the most important. Since scattering coefficients are used to estimate the transmission image for dehazing, the optimal coefficients for effective dehazing must be obtained depending on the level of haze generation. Thus, we estimated the optimal scattering coefficient for 100 synthetic haze images and represented the distribution between the optimal scattering coefficient and dark channels. Moreover, through linear regression of the aforementioned distribution, the equation between scattering coefficients and dark channels was estimated, enabling the estimation of appropriate scattering coefficient. Transmission image for dehazing is defined with a scattering coefficient and a grayscale depth image, obtained from LiDAR 2D projection. Finally, dehazing is performed based on the atmospheric scattering model through the defined atmospheric light and transmission image. The proposed method was quantitatively and qualitatively analyzed through simulation and image quality parameters. Qualitative analysis was conducted through YOLO v3 and quantitative analysis was conducted through MSE, PSNR, SSIM, etc. In quantitative analysis, SSIM showed an average performance improvement of 24%.

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5

Esmonde-White, Francis W. L., i David H. Burns. "A Portable Multi-Wavelength near Infrared Photon Time-of-flight Instrument for Measuring Light Scattering". Journal of Near Infrared Spectroscopy 17, nr 4 (1.01.2009): 167–76. http://dx.doi.org/10.1255/jnirs.847.

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Measured light scattering properties can be used to improve quantitative spectroscopic analyses of turbid samples. Instruments currently used to measure scattering coefficients are not optimised for portability. A hand-held, dual-wavelength instrument was developed and validated for rapid measurement of reduced scattering coefficients in tandem with near infrared spectra. Tissue simulating phantoms composed of Intralipid and dye were used to model clinically relevant optical properties. Time-dependent intensity profiles of diffusely reflected near infrared pulsed laser light were collected from phantoms and processed to estimate scattering coefficients. In turbid solutions, optical scattering was measured at 850 nm and 905 nm with coefficients of variation of 14.1% and 11.6% over a clinically-relevant reduced scattering coefficient range of 1 mm−1 to 6 mm−1. This dual-wavelength scattering measurement provides a practical method for measuring optical scattering. A 35% precision improvement in quantification of an absorbing dye is shown by incorporating the measured reduced scattering coefficients when processing NIR spectra. We discuss the new instrument, methods for estimating the scattering coefficient from the measured temporal profiles and, finally, how the reduced scattering coefficient is used to correct NIR measurements. Correction of near infrared spectra using optical scattering measurements offers one direction for improving practical non-invasive biomedical quantification techniques.

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Blaney, Giles, Angelo Sassaroli i Sergio Fantini. "Method for Measuring Absolute Optical Properties of Turbid Samples in a Standard Cuvette". Applied Sciences 12, nr 21 (27.10.2022): 10903. http://dx.doi.org/10.3390/app122110903.

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Many applications seek to measure a sample’s absorption coefficient spectrum to retrieve the chemical makeup. Many real-world samples are optically turbid, causing scattering confounds which many commercial spectrometers cannot address. R1C1Using diffusion theory and considering absorption and reduced scattering coefficients on the order of 0.01/mm and 1/mm, respectively, we develop a method which utilizes frequency-domain to measure absolute optical properties of turbid samples in a standard cuvette ( 45x10x10mm). Inspired by the self-calibrating method, which removes instrumental confounds, the method uses measurements of the diffuse complex transmittance at two sets of two different source-detector distances. We find: this works best for highly scattering samples (reduced scattering coefficient above 1/mm); higher relative error in the absorption coefficient compared to the reduced scattering coefficient; accuracy is tied to knowledge of the sample’s index of refraction. Noise simulations with 0.1 amplitude and 0.1=1.7mrad phase uncertainty find errors in absorption and reduced scattering coefficients of 4 and 1 , respectively. We expect that higher error in the absorption coefficient can be alleviated with highly scattering samples and that boundary condition confounds may be suppressed by designing a cuvette with high index of refraction. Further work will investigate implementation and reproducibility.

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7

Chen, Zezong, Jian Li, Chen Zhao, Fan Ding i Xi Chen. "The Scattering Coefficient for Shore-to-Air Bistatic High Frequency (HF) Radar Configurations as Applied to Ocean Observations". Remote Sensing 11, nr 24 (11.12.2019): 2978. http://dx.doi.org/10.3390/rs11242978.

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To extend the scope of high frequency (HF) radio oceanography, a new HF radar model, named shore-to-air bistatic HF radar, has been proposed for ocean observations. To explore this model, the first-order scattering coefficient and the second-order electromagnetic scattering coefficient for shore-to-air bistatic HF radar are derived using the perturbation method. In conjunction with the contribution of the hydrodynamic component, the second-order scattering coefficient is derived. Based on the derived scattering coefficients, we analyzed the simulated echo Doppler spectra for various scattering angles and azimuthal angles, operation frequencies, wind speeds, and directions of wind, which may provide the guideline on the extraction of sea state information for shore-to-air bistatic HF radar. The singularities in the simulated echo Doppler spectra are discussed using the normalized constant Doppler frequency contours. In addition, the scattering coefficients of shore-to-air bistatic HF radar are compared with that of monostatic HF radar and land-based bistatic HF radar. The results verify the correctness of the proposed scattering coefficients. The model of shore-to-air bistatic HF radar is effective for ocean observations.

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8

Basak, Soumen, i Parthasarathi Majumdar. "Reflection coefficient for superresonant scattering". Classical and Quantum Gravity 20, nr 13 (12.06.2003): 2929–36. http://dx.doi.org/10.1088/0264-9381/20/13/335.

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Vorlaender, Michael, i Stefan Feistel. "Show your scattering coefficients". Journal of the Acoustical Society of America 152, nr 4 (październik 2022): A209. http://dx.doi.org/10.1121/10.0016032.

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Absorption and scattering coefficients of surfaces are crucial components of room-acoustic simulations. The random-incidence scattering coefficient is the most uncertain metric applied in geometrical acoustics. Databases of scattering coefficients are rare. Their impact on auditory perception in auralizations, however, is relatively well studied. Research directions in developing improved scattering metrics can focus on their relevance for auditory effects, their influence on the spatial sound energy flow, their characterization in angular decomposition, and their estimation with simple rules of thumb. This paper will highlight the state of the art in determining and using scattering coefficients, and it will discuss possible improvements.

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10

Wang, Hai Tao, Xiang Yang Zeng i Yan Shan Liu. "Calculation of the Scattering Coefficient of Large Scale Periodic Structure". Advanced Materials Research 889-890 (luty 2014): 135–39. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.135.

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The periodic structure is common used in engineering to improve the sound diffusion in room acoustics. It usually has large dimensions and it is difficult to calculate the scattering coefficient based on its original scale. In order to represent the scattering coefficients of a large scale periodic structure by those of a smaller one, the relations of the scattering coefficients of the periodic structures with different dimensions are analyzed in this paper. At first, a BMM (Boundary Meshless Method) for calculating the scattering coefficient is derived. The scattering coefficients of the periodic structures which have different numbers of sub-structures are calculated and compared. The computation results of different sub-structure numbers show that the periodic structure with 15 sub-structures can represent the samples which have more sub-structures. In addition, it can be proved that the square samples can be represented by those of the small and rectangular ones which have the same numbers of sub-periods. These conclusions not only greatly enhance the computational efficiency, but also show good prospect for fast evaluation of the periodic structures in engineering applications.

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11

Wu, Zheng-Xue, Chao-Yun Long, Jing Wu, Zheng-Wen Long i Ting Xu. "Scattering in graphene quantum dots under generalized uncertainty principle". International Journal of Modern Physics A 34, nr 31 (10.11.2019): 1950212. http://dx.doi.org/10.1142/s0217751x19502129.

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In this article, the Dirac electron scattering problem on circular barrier of radius [Formula: see text] is studied under the generalized uncertainty principle (GUP). The expressions of scattering coefficients, scattering cross-section and scattering efficiency of massless Dirac particle are obtained by solving the massless Dirac equation under GUP and discussed by numerical methods. It shows that the scattering coefficient, the scattering cross-section, and the scattering efficiency depend explicitly on the GUP parameter [Formula: see text]. For the scattering coefficient [Formula: see text], GUP may cause slight shift in the oscillation position of [Formula: see text] and make some peaks value of [Formula: see text] smaller. For scattering cross-section and scattering efficiency, GUP may also lead to slight shift in their oscillation position and increase of amplitude when the GUP parameter increases.

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12

Burger, T., J. Kuhn, R. Caps i J. Fricke. "Quantitative Determination of the Scattering and Absorption Coefficients from Diffuse Reflectance and Transmittance Measurements: Application to Pharmaceutical Powders". Applied Spectroscopy 51, nr 3 (marzec 1997): 309–17. http://dx.doi.org/10.1366/0003702971940404.

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A measurement and data evaluation technique for the separate determination of the scattering and absorption properties of loose pharmaceutical powders is described. The equation of radiative transfer for diffuse reflectance and transmittance is analytically solved by using a three-flux approximation. Combined transmittance and reflectance measurements then allow one to derive both the scattering and the absorption coefficients. The scattering and absorption coefficients provide more information about particle size, degree of agglomeration, and chemical composition of the samples in comparison to the usual determination of only the ratio of the coefficients from diffuse reflectance measurements on optically thick samples. Furthermore, the theory of diffuse reflectance of optically thick samples according to Kubelka and Munk is compared to the three-flux approximation. The influence of the particle size on the scattering and absorption coefficient is investigated, and it is shown that the assumption of a wavelength-independent scattering coefficient, though often made in reflectance spectroscopy, is not generally valid.

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13

Leskinen, A., A. Arola, M. Komppula, H. Portin, P. Tiitta, P. Miettinen, S. Romakkaniemi, A. Laaksonen i K. E. J. Lehtinen. "Seasonal cycle and source analyses of aerosol optical properties in a semi-urban environment at Puijo station in Eastern Finland". Atmospheric Chemistry and Physics 12, nr 12 (28.06.2012): 5647–59. http://dx.doi.org/10.5194/acp-12-5647-2012.

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Abstract. We introduce a four-year (in 2006–2010) continuous data set of aerosol optical properties at Puijo in Kuopio, Finland. We study the annual and diurnal variation of the aerosol scattering and absorption coefficients, hemispheric backscattering fraction, scattering Ångström exponent, and single scattering albedo, whose median values over this period were 7.2 Mm−1 (at 550 nm), 1.0 Mm−1 (at 637 nm), 0.15, 1.93 (between 450 and 550 nm), and 0.85, respectively. The scattering coefficient peaked in the spring and autumn, being 2–4 times those in the summer and winter. An exception was the summer of 2010, when the scattering coefficient was elevated to ~300 Mm−1 by plumes from forest fires in Russia. The absorption coefficient peaked in the winter when soot-containing particles derived from biomass burning were present. The higher relative absorption coefficients resulted in lower single scattering albedo in winter. The optical properties varied also with wind direction and time of the day, indicating the effect of the local pollutant sources and the age of the particles. Peak values in the single scattering albedo were observed when the wind blew from a paper mill and from the sector without local pollutant sources. These observations were linked, respectively, to the sulphate-rich aerosol from the paper mill and the oxygenated organics in the aged aerosol, which both are known to increase the scattering characteristics of aerosols. Decreases in the single scattering albedo in the morning and afternoon, distinct in the summertime, were linked to the increased traffic density at these hours. The scattering and absorption coefficients of residential and long-range transported aerosol (two separate cloud events) were found to be decreased by clouds. The effect was stronger for the scattering than absorption, indicating preferential activation of the more hygroscopic aerosol with higher scattering characteristics.

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Zhang, L., X. Cao, J. Bao, B. Zhou, J. Huang, J. Shi i J. Bi. "A case study of dust aerosol radiative properties over Lanzhou, China". Atmospheric Chemistry and Physics 10, nr 9 (7.05.2010): 4283–93. http://dx.doi.org/10.5194/acp-10-4283-2010.

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Abstract. The vertical distribution of dust aerosol and its radiative properties are analysed using the data measured by the micropulse lidar, profiling microwave radiometer, sunphotometer, particulate monitor, and nephelometer at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) during a dust storm from 27 March to 29 March 2007. The analysis shows that the dust aerosol mainly exists below 2 km in height, and the dust aerosol extinction coefficient decreases with height. The temporal evolution of aerosol optical depth (AOD) during the dust storm is characterized by a sub-maximum at 22:00 (Beijing Time), 27 March and a maximum at 12:00, 28 March. The AOD respectively derived by lidar and sunphotometer shows a good consistency. The PM10 concentration and aerosol scattering coefficient share similar variation trends, and their maximums both appear at 22:00, 27 March. The aerosol extinction coefficient and relative humidity have the similar trends and their maximums almost appear at the same heights, which presents a correlation between extinction coefficient and relative humidity known as aerosol hygroscopicity. The relative humidity is related with temperature, and then the temperature will affect the aerosol extinction properties by modifying the relative humidity condition. The aerosol extinction coefficient, scattering coefficient, and PM10 concentration present good linear correlations. The correlation coefficients of the aerosol scattering coefficients of 450, 520, and 700 nm and PM10 concentration, of aerosol extinction coefficient retrieved by lidar at 532 nm and PM10 concentration, and of aerosol extinction and scattering coefficient are respectively 0.98, 0.94, and 0.96.

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Ren, Yuhu, Jimo Jian, Wenjiang Tan, Jing Wang, Tao Chen i Wei Xia. "Transition from the ballistic to the snake regime of a femtosecond laser through a turbid medium via Monte Carlo simulation". Laser Physics Letters 19, nr 5 (21.03.2022): 056002. http://dx.doi.org/10.1088/1612-202x/ac5b5c.

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Abstract We study the transition from the ballistic to the snake regime of a femtosecond laser through a turbid medium via Monte Carlo simulation. The results show that the transition depth of the ballistic to the snake regime of a femtosecond laser through a turbid medium is close to the surface of the scattering volume. The transition process depends on the scattering coefficient of the turbid medium. Unlike the decay of the intensities of the ballistic photons governed by Beer–Lambert law, the intensities of the snake photons first increase with an increase of the thickness of the turbid medium and then decrease with a further increase of the thickness, for all scattering coefficients ranging from 10 to 20 cm−1. Further, we study the balance point of the intensity of the ballistic photons and the snake photons, which also depends on the scattering coefficient and the half-acceptance angle. The transmission depth corresponding to the transition balance point decreases with an increase of the scattering coefficient. In addition, for the transition balance point, the product of the transmission depth and scattering coefficient is approximately a constant (∼2) for a specific simulation configuration.

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Gorobets, Yu N. "Scattering coefficient of circular-aperture antenna". Telecommunications and Radio Engineering 57, nr 6-7 (2002): 7. http://dx.doi.org/10.1615/telecomradeng.v57.i6-7.40.

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Hohmann, Martin, Benjamin Lengenfelder, Daniel Muhr, Moritz Späth, Maximilian Hauptkorn, Florian Klämpfl i Michael Schmidt. "Direct measurement of the scattering coefficient". Biomedical Optics Express 12, nr 1 (14.12.2020): 320. http://dx.doi.org/10.1364/boe.410248.

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Atkinson, D., i J. Geschiere. "Inverse scattering: an illicit reflection coefficient". Inverse Problems 2, nr 4 (1.11.1986): L51—L53. http://dx.doi.org/10.1088/0266-5611/2/4/003.

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Lanting, Peter J. H., Peter C. F. Borsboom, Gerard J. te Meerman i Leo P. ten Kate. "Decreased scattering coefficient of blue sclerae". Clinical Genetics 27, nr 2 (23.04.2008): 187–90. http://dx.doi.org/10.1111/j.1399-0004.1985.tb00209.x.

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Zhang, L., X. Cao, J. Bao, B. Zhou, J. Huang, J. Shi i J. Bi. "A case study of dust aerosol radiative properties over Lanzhou, China". Atmospheric Chemistry and Physics Discussions 10, nr 2 (5.02.2010): 2889–914. http://dx.doi.org/10.5194/acpd-10-2889-2010.

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Abstract. The vertical distribution of dust aerosol and its radiative properties are analysed using the data measured by the micropulse lidar, profiling microwave radiometer, sunphotometer, particulate monitor, and nephelometer at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) during a dust storm from 27 March to 29 March 2007. The analysis shows that the dust aerosol mainly exists below 2 km in height, and the dust aerosol extinction coefficient decreases with height. The temporal evolution of aerosol optical depth (AOD) during the dust storm is characterized by a sub-maximum at 22:00 (Beijing Time) on 27 March and a maximum at 12:00 on 28 March. The AOD derived by lidar is compared with that obtained by sunphotometer, and shows a good consistency. The PM10 concentration and aerosol scattering coefficient share identical variation trends, and their maximums both appear at 22:00 on 27 March. The aerosol extinction coefficient and relative humidity have the same trends and their maximums appear at identical heights, showing a correlation between extinction coefficient and relative humidity known as aerosol hygroscopicity. Nevertheless, the correlation between aerosol extinction coefficient and temperature cannot be obviously seen. The aerosol extinction coefficient, scattering coefficient, and PM10 concentration present good linear correlations. The correlation coefficients of the aerosol scattering coefficient and PM10 concentration, of aerosol extinction coefficient and PM10 concentration, and of aerosol extinction and scattering coefficient are respectively 0.98, 0.94, and 0.96.

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Vornovskikh, Polina, Andrei Sushchenko i Igor Prokhorov. "Reconstruction of volume scattering coefficient with considering seabottom scattering layer". Journal of the Acoustical Society of America 146, nr 4 (październik 2019): 2929. http://dx.doi.org/10.1121/1.5137172.

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Wan, Xiao Xia, Zhen Liu i Qiang Liu. "The Ray Scattering Spectral Reflectance Model for Coloring Images". Advanced Materials Research 174 (grudzień 2010): 24–27. http://dx.doi.org/10.4028/www.scientific.net/amr.174.24.

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we proposed a model for reflectance of a medium in ink layer. And the scattering coefficient is more complicated than the refractive index and absorption coefficient due to its complicated scattering laws and multi-direction, and the multi-direction makes different scatting coefficients in different situation. The goal of the work proposed in this dissertation is to develop a new method to analysis the scattering situation using random walk. By analysis the probability of the scattering of the particle, we obtain the reflectance factors of the diffusing medium with the observation geometry. The present model enables one to predict the reflection spectrum of a particle medium, then to estimate the color and brightness.

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Haddadi, Ataollah, Guillaume Hans, Brigitte Leblon, Zarin Pirouz, Satoru Tsuchikawa, Joseph Nader i Kevin Groves. "Determination of Optical Parameters and Moisture Content of Wood with Visible–Near Infrared Spectroscopy". Journal of Near Infrared Spectroscopy 24, nr 6 (1.01.2016): 571–85. http://dx.doi.org/10.1255/jnirs.1174.

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We used the Kubelka-Munk theory equations for calculating the absorption coefficient (Kλ), the scattering coefficient ( Sλ), the transport absorption (σλa), the reduced scattering coefficient [σλs(1 – g)] and the penetration depth (δλ) from visible-near infrared reflectance spectra acquired over thin samples of quaking aspen and black spruce conditioned at three different moisture levels. The computed absorption and scattering coefficients varied from 0.1 mm−1 to 4.0 mm−1 and from 5.5 mm−1 to 10.0 mm−1, respectively. The absorption coefficients varied according to the absorption band, but the scattering coefficients decreased slowly towards high wavelengths. The sample moisture content was then estimated using the partial least squares (PLS) regression method from the Kλ and/or Sλ spectra, and the resulting PLS models were compared to those obtained with raw and transformed [multiplicative scatter corrected (MSC), first and second derivative] absorption spectra. The best PLS models for black spruce, quaking aspen and both species were obtained when only the 800–1800 nm range was used with the raw or MSC spectra. They led to a root mean square error of cross validation ( RMSECV) of 1.40%, 1.09% and 1.23%, respectively, and to a coefficient of determination ( R2CV) higher than 0.94. We also found that the Kλ spectra between 800 nm and 1800 nm can provide PLS models having an acceptable accuracy for moisture content estimation ( R2CV = 0.83 and RMSECV = 2.32%), regardless of the species.

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Беликов, А. В., А. М. Загорулько, С. Н. Смирнов, А. Н. Сергеев, А. А. Михайлова i А. А. Шимко. "Оптические свойства in vitro катарактальных хрусталиков глаза человека в видимом и ближнем ИК диапазонах-=SUP=-*-=/SUP=-". Журнал технической физики 126, nr 5 (2019): 656. http://dx.doi.org/10.21883/os.2019.05.47667.16-19.

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Spectral dependences of absorption coefficient, scattering coefficient, anisotropy factor and reduced scattering coefficient for in vitro human eye lenses of different cataract type are investigated. The spectra of absorption coefficient and reduced scattering coefficient were obtained for the spectral range 400-2300 nm, and the spectra of scattering coefficient and scattering anisotropy factor - for the spectral range 400-1800 nm. The regions of wavelengths within which the spectra of the studied optical characteristics of the human eye lens are not statistically significantly different for samples with different stages of cataract maturity and, conversely, within which they are statistically significantly different, are determined.

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Wang, Chen, Qinqin Zhang, Xiaojing Wu, Tao Tang, Hong Liu, S. W. Zhu, Bruce Z. Gao i X. C. Yuan. "Quantitative Diagnosis of Colorectal Polyps by Spectral Domain Optical Coherence Tomography". BioMed Research International 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/570629.

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The principal aim of this study is to investigate the scattering coefficient of colorectal polyp tissues using an optical coherence tomography (OCT) technique. It combines the existing scattering coefficient model and spectral domain OCT to achieve method of early diagnosis of colorectal polyp in hospitals. Seventeen patients were studied, and a total of 1456 data points were extracted by curve-fitting the OCT signals into a confocal single-backscattering model. The results show that the mean scattering coefficient value for colorectal polyps is 1.91 mm−1(std: ±0.54 mm−1), which is between the values for normal and malignant tissues. In addition, we studied the difference between adenomatous polyps (n=15) and inflammatory polyps (n=2) quantitatively and found that the adenomatous tissues had lower scattering coefficients than the inflammatory ones. The quantitative measurements confirmed that OCT can be used in primary diagnosis to compensate for the deficiencies in methods of pathological diagnosis, with a great potential for early diagnosis of tissues.

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GAO, WANRONG, PENG LEE i XIANLING ZHANG. "CHARACTERIZATION OF VITILIGO BY IN VIVO SCATTERING COEFFICIENT OF HUMAN SKIN". Journal of Innovative Optical Health Sciences 04, nr 01 (styczeń 2011): 67–72. http://dx.doi.org/10.1142/s1793545811001216.

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Scattering coefficients of human skin in vivo with and without vitiligo were measured with optical coherence tomography (OCT). The experimental results show that there exist significant difference between the scattering coefficient of the epidermis of in vivo human skin with and without vitiligo disease. The results may be helpful for quantitatively diagnosing or evaluating the treatment of the disease.

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Stocker, Sabrina, Florian Foschum, Philipp Krauter, Florian Bergmann, Ansgar Hohmann, Claudia Scalfi Happ i Alwin Kienle. "Broadband Optical Properties of Milk". Applied Spectroscopy 71, nr 5 (21.10.2016): 951–62. http://dx.doi.org/10.1177/0003702816666289.

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Dairy products play an important role in our daily nutrition. As a turbid scattering medium with different kinds of particles and droplets, each alteration of these components changes the scattering properties of milk. The goal of this work is the determination of the amount of main scattering components, the fat droplets and the casein micelles, by understanding the light propagation in homogenized milk and in raw milk. To provide the absolute impact of these milk components, the geometrical and optical properties such as the size distribution and the refractive index (RI) of the components have to be examined. We determined the reduced scattering coefficient [Formula: see text] and the absorption coefficient [Formula: see text] from integrating sphere measurements. By use of a collimated transmission setup, the scattering coefficient [Formula: see text] was measured. Size measurements were performed to validate the influence of the fat droplet size on the results of the scattering properties; also, the RI of both components was determined by the said coefficients. These results were used to determine the absolute impact of the milk components on the scattering behavior. By fitting Mie theory calculations on scattering spectra [Formula: see text] and [Formula: see text] from different raw milk samples, it was possible to get reliable values for the concentrations of fat and casein and for the size of the fat droplets. By destroying the casein micelles, it was possible to separate the influence of the different scattering components on scattering behavior.

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Pereira, S. N., F. Wagner i A. M. Silva. "Continuous measurements of near surface aerosols in the south-western European (Portugal) region in 2006–2008". Advances in Science and Research 3, nr 1 (1.04.2009): 1–4. http://dx.doi.org/10.5194/asr-3-1-2009.

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Abstract. Scattering and absorption coefficients near the ground were measured in Évora, Portugal, in the period of 2006 to 2008. The average scattering coefficient, at the wavelength of 550 nm, for the whole period of measurements was found to be 40.3 Mm−1 and the absorption coefficient, at the wavelength of 670 nm, 8.6 Mm−1. These values are comparable to those measured in rural or background locations and reflect the small size of the city and relatively low magnitude of anthropogenic production at the site. A marked seasonal variation was found for the absorption coefficient, with a significant increase from 5.8 Mm−1, in summer, to 13.4 Mm−1, in winter. Regarding black carbon mass concentrations, this twofold increase, from 0.9 to 2.0 μgm−3, is mainly attributed to the wood combustion used for heating in conjunction with lower boundary layer mixing heights. The average scattering coefficient presented a more complex behaviour, although with a tendency for higher values in winter and lower values in spring.

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Richter, Scott J., i Robert H. Stavn. "Determining Functional Relations in Multivariate Oceanographic Systems: Model II Multiple Linear Regression". Journal of Atmospheric and Oceanic Technology 31, nr 7 (1.07.2014): 1663–72. http://dx.doi.org/10.1175/jtech-d-13-00210.1.

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Abstract A method for estimating multivariate functional relationships between sets of measured oceanographic, meteorological, and other field data is presented. Model II regression is well known for describing functional relationships between two variables. However, there is little accessible guidance for the researcher wishing to apply model II methods to a multivariate system consisting of three or more variables. This paper describes a straightforward method to extend model II regression to the case of three or more variables. The multiple model II procedure is applied to an analysis of the optical spectral scattering coefficient measured in the coastal ocean. The spectral scattering coefficient is regressed against both suspended mineral particle concentration and suspended organic particle concentration. The regression coefficients from this analysis provide adjusted estimates of the mineral particle scattering cross section and the organic particle scattering cross section. Greater accuracy and efficiency of the coefficients from this analysis, compared to semiempirical coefficients, is demonstrated. Examples of multivariate data are presented that have been analyzed by partitioning the variables into arbitrary bivariate models. However, in a true multivariate system with correlated predictors, such as a coupled biogeochemical cycle, these bivariate analyses yield incorrect coefficient estimates and may result in large unexplained variance. Employing instead a multivariate model II analysis can alleviate these problems and may be a better choice in these situations.

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30

Kaewkhao, Jakrapong, P. Lofimkitjaroenporn, S. Tuscharoen, T. Kittiauchawal, W. Chewpraditkul i Pichet Limsuwan. "Measurement of Mass Attenuation Coefficients of Blue Sapphire at Different Photon Energy by Compton Scattering Technique". Applied Mechanics and Materials 103 (wrzesień 2011): 71–75. http://dx.doi.org/10.4028/www.scientific.net/amm.103.71.

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The mass attenuation coefficients of blue sapphire were measured at the different energy of γ-rays using the Compton scattering technique. There are in good agreement of scattered gamma rays energies between theoretical value and experimental value, reflecting the validation of Compton scattering system setup. The results show that, the experimental values of mass attenuation coefficient are in good agreement with the theoretical values. The mass attenuation coefficients increase with the decrease in gamma rays energies. This may be attributed to the higher photon interaction probability of blue sapphire at lower energy. This result is a first report of mass attenuation coefficient of blue sapphire at different gamma rays energies.

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31

Hassanabadi, Hassan, Hadi Sobhani i Won Sang Chung. "Scattering Study of Fermions due to Double Dirac Delta Potential in Quaternionic Relativistic Quantum Mechanics". Advances in High Energy Physics 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/8124073.

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We have studied the scattering problem of relativistic fermions from a quaternionic double Dirac delta potential. We have used Dirac equation in the presence of the scalar and vector potentials in the quaternionic formalism of relativistic quantum mechanics to study the problem. The wave functions of different regions have been derived. Then, using the reflection coefficient, transmission coefficient, and the continuity equation, the scattering problem has been investigated in detail. It has been shown that we have faced some fluctuations in the reflection and transmission coefficients.

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32

Nishidate, Izumi, Tomohiro Ishizuka, Afrina Mustari, Keiichiro Yoshida, Satoko Kawauchi, Shunichi Sato i Manabu Sato. "Evaluation of Cerebral Hemodynamics and Tissue Morphology of In Vivo Rat Brain Using Spectral Diffuse Reflectance Imaging". Applied Spectroscopy 71, nr 5 (5.07.2016): 866–78. http://dx.doi.org/10.1177/0003702816657569.

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We investigated a quantitative imaging of reduced scattering coefficients μs’( λ) and the absorption coefficients μa( λ) of in vivo cortical tissues in the range from visible to near-infrared (NIR) wavelengths based on diffuse reflectance spectral imaging technique. In this method, diffuse reflectance images of in vivo cortical tissue are acquired at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm). A multiple regression analysis aided by the Monte Carlo simulation for the absorbance spectra is then utilized to estimate the optical coefficients of cortical tissue. This analysis calculates the concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin, the scattering amplitude a and the scattering power b. The spectrum of absorption coefficient is deduced from the estimated concentrations of oxygenated hemoglobin and deoxygenated hemoglobin. The spectrum of reduced scattering coefficient is determined by the estimated scattering amplitude and scattering power. The particle size distribution of microstructure is calculated from the estimated scattering power b for evaluating the morphological change in brain tissue quantitatively. Animal experiments with in vivo exposed brain of rats demonstrated that the responses of the absorption properties to hyperoxic and anoxic conditions are in agreement with the expected well-known cortical hemodynamics. The average particle size was significantly reduced immediately after the onset of anoxia and then it was changed into an increase, which implied the swelling and shrinkage of the cellular and subcellular structures induced by loss of tissue viability in brain tissue.

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33

D'Errico, Raffaele, i Alain Sibille. "Single and Multiple Scattering in UWB Bicone Arrays". International Journal of Antennas and Propagation 2008 (2008): 1–12. http://dx.doi.org/10.1155/2008/129584.

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An analysis of interactions between radiators in a UWB biconical array, drawing attention to single and multiple scatterings, is carried out. The complementarity between electrical coupling and radiation scattering is argued. The point source approximation is discussed and shown to be insufficient. An approximation of radiation scattering based on angular averaging of the scattering coefficient is proposed. This approach yields a reduction of the problem complexity, which is especially interesting in UWB multiple antenna systems, because of the large bandwidth. Multiple scattering between radiators is shown to be a second-order effect. Finally, a time domain approach is used in order to investigate pulse distortion and quantify the exactness of the proposed scattering model.

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34

Yan, Qingyun, i Weimin Huang. "GNSS-R Delay-Doppler Map Simulation Based on the 2004 Sumatra-Andaman Tsunami Event". Journal of Sensors 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/2750862.

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A new method for simulating Global Navigation Satellite System-Reflectometry (GNSS-R) delay-Doppler maps (DDMs) of a tsunami-dominant sea surface is presented. In this method, the bistatic scattering Z-V model, the sea surface mean square slope model of Cox and Munk, and the tsunami-induced wind perturbation model are employed. The feasibility of the Cox and Munk model under a tsunami scenario is examined by comparing the Cox and Munk model based scattering coefficient with the Jason-1 measurement. A good consistency between these two results is obtained with a correlation coefficient of 0.93. After confirming the applicability of the Cox and Munk model for a tsunami-dominated sea, this study provides the simulations of the scattering coefficient distribution and the corresponding DDMs of a fixed region of interest before and during the tsunami. In the final analysis, by subtracting the simulation results that are free of tsunami from those with presence of tsunami, the tsunami-induced variations in scattering coefficients and DDMs can be clearly observed. As a result, the tsunami passage can be readily interpreted.

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35

Sefkow, A., M. Bree i M. A. MyCek. "Method for Measuring Cellular Optical Absorption and Scattering Evaluated Using Dilute Cell Suspension Phantoms". Applied Spectroscopy 55, nr 11 (listopad 2001): 1495–501. http://dx.doi.org/10.1366/0003702011953711.

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The opal glass method (OGM) is a standard technique used by the ocean optics community to measure the spectral absorption coefficients of algal suspensions. We present and evaluate this method for its potential application to measurements of the inherent optical properties (optical absorption and scattering coefficients) of dilute mammalian cell suspensions, as an alternative to the integrating sphere method. In a series of controlled experiments on absorbing and scattering phantoms (Evans blue dye and polystyrene spheres 1–20 μm in diameter), separation of absorption and scattering was possible with less than 20% error in absorption coefficient estimates for particles with major scattering components in the size range of 2–5 μm.

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36

HIROSAWA, HARUTO, i YUKIHIKO MATSUZAKA. "Measurement of scattering coefficient σ° of trees". International Journal of Remote Sensing 8, nr 4 (kwiecień 1987): 609–19. http://dx.doi.org/10.1080/01431168708948668.

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37

Chen, Jing, Xiangrong Liu, Changjiang Liu i Xichao Dong. "Complex forward scattering coefficient for signal characterisation". Journal of Engineering 2019, nr 19 (1.10.2019): 5524–28. http://dx.doi.org/10.1049/joe.2019.0032.

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38

Katlein, Christian, Marcel Nicolaus i Chris Petrich. "The anisotropic scattering coefficient of sea ice". Journal of Geophysical Research: Oceans 119, nr 2 (luty 2014): 842–55. http://dx.doi.org/10.1002/2013jc009502.

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39

Chauchard, F., J. M. Roger, V. Bellon-Maurel, C. Abrahamsson, S. Andersson-Engels i S. Svanberg. "MADSTRESS: A Linear Approach for Evaluating Scattering and Absorption Coefficients of Samples Measured Using Time-Resolved Spectroscopy in Reflection". Applied Spectroscopy 59, nr 10 (październik 2005): 1229–35. http://dx.doi.org/10.1366/000370205774430828.

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Time-resolved spectroscopy is a powerful technique permitting the separation of the scattering properties from the chemical absorption properties of a sample. The reduced scattering coefficient and the absorption coefficient are usually obtained by fitting diffusion or Monte Carlo models to the measured data using numerical optimization techniques. However, these methods do not take the spectral dimension of the data into account during the evaluation procedure, but evaluate each wavelength separately. A procedure involving multivariate methods may seem more appealing for people used to handling conventional near-infrared data. In this study we present a new method for processing TRS spectra in order to compute the absorption and reduced scattering coefficients. This approach, MADSTRESS, is based on linear regression and a two-dimensional (2D) interpolation procedure. The method has allowed us to calculate absorption and scattering coefficients of apples and fructose powder. The accuracy of the method was good enough to provide the identification of fructose absorption peaks in apple absorption spectra and the construction of a calibration model predicting the sugar content of apples.

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40

Leskinen, A., A. Arola, M. Komppula, H. Portin, P. Tiitta, P. Miettinen, S. Romakkaniemi, A. Laaksonen i K. E. J. Lehtinen. "Seasonal cycle and source analyses of aerosol optical properties in a semi-urban environment at Puijo station in Eastern Finland". Atmospheric Chemistry and Physics Discussions 12, nr 2 (10.02.2012): 4719–54. http://dx.doi.org/10.5194/acpd-12-4719-2012.

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Abstract. We introduce a four-year (2006–2010) continuous data set of aerosol optical properties at Puijo in Kuopio, Finland. We study the annual and diurnal variation of the aerosol scattering and absorption coefficients, hemispheric backscattering fraction, scattering Ångström exponent, and single scattering albedo, whose averages over this period were 11.1 Mm−1 (at 550 nm), 1.5 Mm−1 (at 670 nm), 0.13, 1.9, and 0.83, respectively. The scattering coefficient peaked in the spring and autumn, being 2–4 times those in the summer and winter. An exception was the summer of 2010, when the the scattering coefficient was elevated to ~300 Mm−1 by the plumes from forest fires in Russia. The absorption coefficient peaked in the winter with values of 2–3 times those in the summer. The single scattering albedo was lowest in the winter when more biomass burning derived, soot-containing aerosols were present. The optical properties varied also with wind direction and time of the day, indicating the effect of the local pollutant sources and the age of the particles. Peak values in the single scattering albedo were observed when the wind blew from a paper mill and from the sector without local pollutant sources. These observations were linked to the sulphate-rich aerosol from the paper mill and the oxygenated organics in the aged aerosol, which both are known to increase the scattering characteristics of aerosols. Changes in the single scattering albedo in the morning and afternoon in the summertime were linked to the increased traffic density at these hours. The scattering and absorption coefficients were found to be decreased by clouds. The effect was stronger for the scattering than absorption, indicating preferential activation of the more hygroscopic aerosol with higher scattering characteristics. What happens to the aerosol optical properties during a cloud event when the air masses come from different directions with different local sources, is under a more detailed inspection. Also, more aerosol mass spectrometry data will be analyzed in order to strengthen our knowledge about the role of the chemical composition of the aerosol particles in their activation into cloud droplets.

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Marshall, Julia, Ulrike Lohmann, W. Richard Leaitch, Nicole Shantz, Lisa Phinney, Desiree Toom-Sauntry i Sangeeta Sharma. "Optical Properties of Aerosol Particles over the Northeast Pacific". Journal of Applied Meteorology 44, nr 8 (1.08.2005): 1206–20. http://dx.doi.org/10.1175/jam2267.1.

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Abstract In July 2002, atmospheric aerosol measurements were conducted over the northeast Pacific Ocean as part of the Subarctic Ecosystem Response to Iron Enhancement Study (SERIES). The following aerosol quantities were measured: particle number size distribution, particle scattering and backscattering coefficients at three wavelengths, particle absorption coefficient at one wavelength, and size-segregated particle chemical composition. Using Mie theory to calculate the aerosol particle scattering and absorption coefficients from the size distribution and chemical measurements, closure with the measured optical coefficients is not attained. Discrepancies between the calculated and measured scattering and backscattering coefficients are largely a result of the fact that the nephelometer measures scattering only between 7° and 170°. Over 90% of the total scattering and 50% of the backscattering in this study was not measured by the nephelometer because of the missing forward-scattering (0°–7°) and backscattering (170°–180°) segments of the phase function. During this study the majority of the total scattering and backscattering in the marine boundary layer of this region was a result of coarse particles consisting almost entirely of sea salt.

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42

Zhao, W., X. Xu, M. Dong, W. Chen, X. Gu, C. Hu, Y. Huang, X. Gao, W. Huang i W. Zhang. "Development of a cavity enhanced aerosol albedometer". Atmospheric Measurement Techniques Discussions 7, nr 3 (26.03.2014): 2981–3019. http://dx.doi.org/10.5194/amtd-7-2981-2014.

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Abstract. We report on the development of a cavity enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS) approach and an integrating sphere (IS) for simultaneous in situ measurements of aerosol scattering and extinction coefficients in the exact same sample volume. The cavity enhanced albedometer employed a blue light-emitting diode (LED) based IBBCEAS approach for the measurement of wavelength-resolved aerosol optical extinction over the spectral range of 445–480 nm. An integrating sphere nephelometer coupled to the IBBCEAS setup was used for the measurement of aerosol scattering. The scattering signal was measured with a single channel photomultiplier tube (PMT), providing an integrated value over a narrow bandwidth (FWHM ~ 9 nm) in the spectral region of 465–474 nm. A scattering coefficient at a wavelength of 470 nm was deduced as an averaged scattering value and used for data analysis and instrumental performance comparison. Performance evaluation of the albedometer was carried out using laboratory-generated particles and ambient aerosol. The scattering and extinction measurements of monodisperse polystyrene latex (PSL) spheres generated in laboratory proved excellent correlation between two channels of the albedometer. The retrieved refractive index (RI) from the measured scattering and extinction efficiencies agreed well with the values reported in previously published papers. Aerosol light scattering and extinction coefficients, single scattering albedo (SSA) and NO2 concentrations in an ambient sample were directly and simultaneously measured using the developed albedometer. The developed instrument was validated via an intercomparison of the measured aerosol scattering coefficient and NO2 trace concentration against a TSI 3563 integrating nephelometer and a chemiluminescence detector, respectively.

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43

Ganf, GG, RL Oliver i AE Walsby. "Optical properties of Gas-vacuolate cells and colonies of Microcystis in relation to light Attenuation in a Turbid, Stratified Reservoir (Mount Bold Reservoir, South Australia)". Marine and Freshwater Research 40, nr 6 (1989): 595. http://dx.doi.org/10.1071/mf9890595.

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Profiles of downwelling and upwelling irradiance were measured in a stratified, turbid reservoir, when Microcystis aeruginosa formed a significant proportion of the phytoplankton community. The attenuation coefficient (Kd) was c. 2.1 m-1 and the reflectance (R) c. 0.03. Application of Kirk's simulation model relating apparent and inherent optical properties enabled calculation of coefficients of absorption (a; 1.3-1.6 m-') and scattering (6; 5-7 m-1). The asymptotic diffuse backscattering coefficient (0.2 m-1) was derived from the relationship b′b = 3.6 RaKd, a slight modification of Kirk's original equation. Turbidity measurements supported the general rule that nephelometric turbidity was numerically equivalent to the scattering coefficient. There was good agreement between the measured light profile and one reconstructed from inherent optical properties using the relationship between Kd, a and b. The optical properties of cells and colonies of Microcystis were investigated before and after the collapse of gas vacuoles. The Chla-specific absorption coefficient for cells (0.0138 m2 mg,-1 Chla) was higher than for colonies (0.0106 m2 mg,-1 Chla) at a depth equivalent to 0.2 m. Both coefficients decreased with increasing depth as the spectral composition changed. The Chla-specific scattering coefficient for vacuolate cells (0.14 m2 mg,-1 Chla) was greater than for colonies (0.11 m2 mg,-1 Chla), and a similar correspondence occurred for non-vacuolate cells and colonies (0.029 and 0.020 m2 mg,-1 Chla respectively). These measurements illustrate the package effect and also that c. 80% of light scattering is due to gas vacuoles. The relationship between pressure-sensitive turbidity and gas-vacuole volume suggested that 1 gL mL-1 was equivalent to a turbidity of 2 NTU. These optical characteristics, combined with the buoyant nature of Microcystis, suggest that it is a canopy species.

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44

Giraev K. M., Ashurbekov N. A., Israpov E. Kh., Shakhsinov G. Sh., Abdulaev V. R., Rabadanov K. M. i Isaeva Z. M. "Study on the effect of low-temperature atmospheric pressure plasma jet on the morphofunctional properties of living tissues (in vivo)". Optics and Spectroscopy 130, nr 5 (2022): 637. http://dx.doi.org/10.21883/eos.2022.05.54452.2697-21.

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The results of spectral-fluorescent and diffuse-optical studies of living tissues under the effect of low-temperature atmospheric pressure plasma jet in a mixture of air and argon are presented. Potential fluorophores are identified and coefficients of optical absorption and transport scattering of tissues are determined. It was revealed plasma jet irradiation of tissue leads to an increase in the intensity of fluorescence and the diffuse reflection coefficient, which is linked with a twofold increase in the transport scattering coefficient and a change in the concentration of endogenous chromophores --- a reducing water content, lipids and bilirubin to 20%, and an increasing levels of oxygen saturation to 10%. On the basis of the analysis, it is shown that the therapeutic effect of low-temperature plasma can be associated with increased antioxidant protection and the development of compensatory dehydration processes. Keywords: biological tissues, cold plasma, probing, spectroscopy, fluorescence, diffuse reflection, optical coefficients, light scattering, biochemistry, morphology.

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45

Edström, Per, Magnus Neuman i Ludovic G. Coppel. "A partial explanation of the dependence between light scattering and light absorption in the Kubelka-Munk model". Nordic Pulp & Paper Research Journal 27, nr 2 (1.05.2012): 426–30. http://dx.doi.org/10.3183/npprj-2012-27-02-p426-430.

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Abstract The Kubelka-Munk scattering and absorption coefficients of a set of paper samples are assessed using reflectance measurements in d/0 geometry. The coefficients display the widely studied dependence between light scattering and light absorption, since the light scattering coefficient decreases in regions of high absorption. It is shown using general radiative transfer theory that part of this dependence can be explained and eliminated by taking into account the geometry of the d/0 instrument and the single scattering anisotropy, thus capturing the angular variations of the light reflected from the samples. These findings allow the papermaker to better predict the reflectance from mixtures of pulps, fillers, dye, and FWA, and to better evaluate bleaching efforts.

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46

Lacombe, C., J. L. Steinberg, C. C. Harvey, D. Hubert, A. Mangeney i M. Moncuquet. "Density fluctuations measured by ISEE 1-2 in the Earth's magnetosheath and the resultant scattering of radio waves". Annales Geophysicae 15, nr 4 (30.04.1997): 387–96. http://dx.doi.org/10.1007/s00585-997-0387-5.

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Abstract. Radio waves undergo angular scattering when they propagate through a plasma with fluctuating density. We show how the angular scattering coefficient can be calculated as a function of the frequency spectrum of the local density fluctuations. In the Earth's magnetosheath, the ISEE 1-2 propagation experiment measured the spectral power of the density fluctuations for periods in the range 300 to 1 s, which produce most of the scattering. The resultant local angular scattering coefficient can then be calculated for the first time with realistic density fluctuation spectra, which are neither Gaussian nor power laws. We present results on the variation of the local angular scattering coefficient during two crossings of the dayside magnetosheath, from the quasi-perpendicular bow shock to the magnetopause. For a radio wave at twice the local electron plasma frequency, the scattering coefficient in the major part of the magnetosheath is b(2fp) ≃ 0.5 – 4 × 10–9 rad2/m. The scattering coefficient is about ten times stronger in a thin sheet (0.1 to1RE) just downstream of the shock ramp, and close to the magnetopause.

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47

Chaffin, Nathan C., i Peter R. Griffiths. "Role of Scattering Coefficients in Extended Near-Infrared Diffuse Reflection Spectrometry". Applied Spectroscopy 52, nr 2 (luty 1998): 218–21. http://dx.doi.org/10.1366/0003702981943527.

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The role of the bulk scattering coefficient in extended near-infrared diffuse reflection (DR) spectrometry of materials with similar or identical absorption coefficients is demonstrated. Spectral differences that arise from intraclass variation in scattering coefficient strongly affect the ability to interpret certain spectral regions. Profound intraclass differences in both band intensities and band shapes in the DR spectra of both polyethylene and polystyrene samples are shown. The effects of saturation and Fresnel reflection are discussed. The enhancement of absorption by the matrix and other analytes in DR spectrometry through the addition of a liquid with an index of refraction which matches that of the matrix is also demonstrated.

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48

Stoupin, Stanislav. "X-ray scattering from a plane parallel slab using radiation transfer considerations". Journal of Applied Crystallography 53, nr 5 (20.08.2020): 1236–42. http://dx.doi.org/10.1107/s1600576720010110.

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The X-ray scattering power of a plane parallel homogeneous slab of material is derived using radiation intensity transfer equations. The scattering power scales with the ratio of the scattering coefficient of interest to the total attenuation coefficient. The results can be used to guide the choice of slab thickness, scattering geometry and photon energy to maximize the scattering power in both elastic and inelastic X-ray scattering experiments.

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49

Burger, T., J. Fricke i J. Kuhn. "NIR Radiative Transfer Investigations to Characterise Pharmaceutical Powders and Their Mixtures". Journal of Near Infrared Spectroscopy 6, nr 1 (styczeń 1998): 33–40. http://dx.doi.org/10.1255/jnirs.118.

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A measurement and data evaluation technique to determine quantitatively and separately the scattering and absorption coefficients of disperse media has been applied to pharmaceutical powders and their mixtures. This technique uses a 3-flux approximation of the equation of radiative transfer to evaluate analytically directional-hemispherical reflectance and transmittance data with the boundary conditions adjusted to the experimental set-up in order to derive the scattering and absorption coefficient. The performance of this technique is demonstrated by applying it to a variety of pharmaceutical powders and comparing it to Kubelka–Munk's 2-flux approximation. By applying this technique, more information about the investigated powders (e.g. particle size, degree of agglomeration or chemical composition) compared to diffuse reflectance measurements on optically thick samples can be obtained. From the latter only the ratio of the scattering to the absorption coefficient is determined. Using lactose and ascorbic acid, the effects of varying particle size and particles size distribution on the scattering and absorption coefficients are shown. Additionally this technique has been applied to powder mixtures with different contents of acetylsalicylacid and microcrystalline cellulose to demonstrate the usefullness of this technique for quantitative analysis.

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50

Rosati, B., E. Herrmann, S. Bucci, F. Fierli, F. Cairo, M. Gysel, R. Tillmann i in. "Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements". Atmospheric Chemistry and Physics Discussions 15, nr 13 (9.07.2015): 18609–51. http://dx.doi.org/10.5194/acpd-15-18609-2015.

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Abstract. Vertical profiles of aerosol optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ~ 50–800 m above ground. Determined properties included the aerosol size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a LIDAR system provided aerosol extinction coefficients for a vertically resolved comparison between in-situ and remote sensing results. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20% was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 to 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ~ 10 local time) before the mixed layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ~ 12 local time) the ML was fully developed, resulting in constant extinction coefficients at all altitudes measured on the Zeppelin NT. LIDAR results captured these dynamic features well and good agreement was found for the extinction coefficients compared to the in-situ results, using fixed LIDAR ratios (LR) between 30 and 70 sr for the altitudes probed with the Zeppelin. These LR are consistent with values for continental aerosol particles that can be expected in this region.

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