Studies on Leaf Characteristics of a Cline of Eucalyptus urnigera From Mount Wellington, Tasmania. II. Reflection, Transmission and Absorption of Radiation.

1974 ◽  
Vol 22 (4) ◽  
pp. 701 ◽  
Author(s):  
DA Thomas ◽  
HN Barber
Keyword(s):  
Diffuse Reflection ◽  
Wave Band ◽  
Total Radiation ◽  
Visible Radiation ◽  
Transmission Coefficients ◽  
Radiation Transmission ◽  
Transmission And Absorption ◽  
Coefficients Of Absorption ◽  
Wax Crystals ◽  
Good Agreement

Coefficients of reflection of green and glaucous leaves of Eucalyptus urnigera were, respectively, 26 % and 40% for total radiation and 13% and 30% for visible radiation. Transmission coefficients varied only slightly between leaves differing in glaucousness, being about 24 % and 6% for total and visible radiation respectively. These properties resulted in coefficients of absorption of total radiation varying from 50% for green leaves to 37% for glaucous leaves and of visible radiation from 82% to 66 %. The coefficients for total radiation were measured by means of a hemispherical integrating radiometer and those for radiation over the wave band of 350-1350 nm by means of a spectrophotometer. There was good agreement between the two methods. The differences in these spectral properties between the two leaf types are attributed to diffuse reflection by the wax crystals on the surface of the glaucous leaf.

scholarly journals Propagation Characteristics of Oblique Incident Terahertz Wave in Nonuniform Dusty Plasma

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Yunhua Cao ◽  
Haiying Li ◽  
Zhe Wang ◽  
Zhensen Wu
Keyword(s):  
Dusty Plasma ◽  
Terahertz Wave ◽  
Dust Particles ◽  
Number Density ◽  
Propagation Characteristics ◽  
Absorption Coefficients ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Propagation Matrix ◽  
Transmission And Absorption

Propagation characteristics of oblique incident terahertz wave from the nonuniform dusty plasma are studied using the propagation matrix method. Assuming that the electron density distribution of dusty plasma is parabolic model, variations of power reflection, transmission, and absorption coefficients with frequencies of the incident wave are calculated as the wave illuminates the nonuniform dusty plasma from different angles. The effects of incident angles, number density, and radius of the dust particles on propagation characteristics are discussed in detail. Numerical results show that the number density and radius of the dust particles have very little influences on reflection and transmission coefficients and have obvious effects on absorption coefficients. The terahertz wave has good penetrability in dusty plasma.

scholarly journals TRANSMISSION OF RANDOM WAVES THROUGH PILE BREAKWATERS

1986 ◽  
Vol 1 (20) ◽  
pp. 169 ◽  
Author(s):  
Clifford L. Truitt ◽  
John B. Herbich
Keyword(s):  
Random Waves ◽  
Pile Spacing ◽  
Transmission Coefficients ◽  
Pile Diameter ◽  
Model Pile ◽  
Incident Waves ◽  
Good Agreement ◽  
Monochromatic Waves

Several previous investigators have conducted experiments leading to expressions for predicting the transformation of waves passing through closely-spaced pile breakwaters. The present study extends those earlier experiments using monochromatic waves to the case of a spectrum of random waves. Records of incident waves and of waves after transmission through a model pile breakwater were compared to determine a coefficient of transmission. Results are presented for several cases of pile spacing and pile diameter. Good agreement is found between observed transmission coefficients and those predicted using the expression proposed by Hayashi et al. (1966).

Visible Radiation Transfer in a Black Ink Suspension

1980 ◽  
Vol 102 (4) ◽  
pp. 709-714 ◽  
Author(s):  
T. R. Wagner ◽  
F. P. Incropera ◽  
W. G. Houf
Keyword(s):  
Radiation Intensity ◽  
Forward Direction ◽  
Radiative Properties ◽  
Discrete Ordinate ◽  
Visible Radiation ◽  
Intensity Measurements ◽  
Radiation Fluxes ◽  
India Ink ◽  
Half Angle ◽  
Good Agreement

Measurements of the directional and spatial distribution of the radiation intensity have been made for an irradiated India ink suspension, and the results have been used to determine radiation fluxes associated with the forward and backward directions. The inherent radiative properties of the ink have also been measured and used with appropriate theories (the discrete ordinate and three-flux methods) to predict the radiation field within the suspension. For the prescribed laboratory conditions, the radiation is concentrated within a cone of half angle θ ≈ 0.85 rad throughout the suspension, and for this region good agreement is obtained between the intensity measurements and predictions based on the discrete ordinate method. Good agreement is also obtained between radiation fluxes measured for the forward direction and predictions based on both the discrete ordinate and three-flux methods. Agreement between the predicted and measured intensities for θ ≳ 0.85 rad, as well as agreement between predicted and measured radiation fluxes for the backward direction, is less satisfactory. Differences are attributed to uncertainties in the radiation intensity and phase function measurements.

scholarly journals Broad Band Equal-Length And Equal-Width Substrate Integrated Waveguide Four Channel Power Divider

2015 ◽  
Vol 37 ◽  
pp. 334
Author(s):  
Masoud Khoubroo Eslamloo ◽  
Pejman Mohammadi
Keyword(s):  
Return Loss ◽  
Propagation Constant ◽  
Broad Band ◽  
Equal Length ◽  
Power Divider ◽  
Substrate Integrated Waveguide ◽  
Transmission Coefficients ◽  
Measurement Results ◽  
Simulation Results ◽  
Good Agreement

In this letter a novel broad band substrate integrated waveguide (SIW) power divider is proposed. It consist of four output channels made by SIW with equal length and equal width. Design equations and process are given with mathematical analysis. The propagation constant of the output signals have been adjusted by utilize only four via in the middle of the output arms. As a result a novel equal output power divider, is obtained accordingly. The experimental results of a prototype at 10 GHz shows 3.1 GHz bandwidth in both simulation and measurement results. Return loss and transmission coefficients have good agreement with simulation results in considered band.

OPTICAL SPECTRA OF SOME PATHOLOGICAL CONDITIONS OF STOMACH TISSUES

2006 ◽  
Vol 20 (01) ◽  
pp. 25-36 ◽  
Author(s):  
K. M. GIRAEV ◽  
N. A. ASHURBEKOV ◽  
O. V. KOBSEV
Keyword(s):  
Light Scattering ◽  
Diffuse Reflection ◽  
Optical Parameters ◽  
Approximation Methods ◽  
Reflection Spectra ◽  
Pathological Changes ◽  
Pathological Conditions ◽  
Flux Model ◽  
And Diffusion ◽  
Coefficients Of Absorption

Diffuse reflection spectra, diffuse and collimated transmittance spectra of the mucous tissue of stomach anthrus in norm and at a low-differential form of stomach cancer are measured in 300–800 nm spectrum range. The optical coefficients of absorption (μa), scattering (μs) and anisotropy factor (g) for tissues with pathological changes have been calculated by the three-flux model and diffusion approximation methods. It has been determined that the magnitude of optical parameters grows with the development of malignant processes in stomach tissues which indicates the prevalence of forward light scattering and the increase in Mi scatter contribution to the total scattering coefficient of malignant tissues. It has also been shown that the application of two independent theories as methods of tissues' optical parameters determination (μa,μs,g) gives satisfactorily similar results.

Coupled Structure and Radiation Analysis of Acetylene/Air Flames

1992 ◽  
Vol 114 (2) ◽  
pp. 487-493 ◽  
Author(s):  
J. P. Gore ◽  
U.-S. Ip ◽  
Y. R. Sivathanu
Keyword(s):  
Heat Loss ◽  
Structure Analysis ◽  
Radiative Heat ◽  
Source Term ◽  
Flame Structure ◽  
New Method ◽  
Visible Radiation ◽  
Radiative Heat Loss ◽  
The Mean ◽  
Good Agreement

A coupled radiation-structure analysis of turbulent, non-premixed, strongly radiating acetylene/air flames is described. The analysis extends the laminar flamelet concept to include the effects of local radiative heat loss/gain. A new method for the calculation of the radiative source term is presented. New measurements of mean and fluctuating emission temperatures and radiation intensities, and previous data concerning flame structure are used to evaluate the predictions. Results show good agreement between measurements and predictions of flame structure similar to past uncoupled calculations. The mean emission temperatures and the mean visible radiation intensities are substantially underpredicted by the uncoupled analysis. The coupled calculations provide reasonable estimates of both quantities.

scholarly journals On the Transfer of Visible Radiation through Sea Ice and Snow

1963 ◽  
Vol 4 (34) ◽  
pp. 481-484 ◽  
Author(s):  
Charles W. Thomas
Keyword(s):  
Sea Ice ◽  
Significant Role ◽  
Crystal Size ◽  
Wave Length ◽  
Visible Radiation ◽  
Absorption Properties ◽  
Snow Conditions ◽  
Coefficients Of Absorption

Abstract Coefficients of absorption of visible radiation are determined for sea ice and snow as a function of porosity of the medium and wave-length of energy refracted into it. A comparison is made between the values derived and those obtained by other investigators under similar snow conditions. A difference in results suggests a significant rôle of crystal size and orientation in the absorption properties of sea ice and snow.

The influence of street furniture, tree trunks, and traffic in urban scenarios on ray tracing simulations in the millimeter wave band

2016 ◽  
Vol 8 (4-5) ◽  
pp. 785-793 ◽  
Author(s):  
Bariş Göktepe ◽  
Michael Peter ◽  
Richard J. Weiler ◽  
Wilhelm Keusgen
Keyword(s):  
Ray Tracing ◽  
Wave Band ◽  
Propagation Characteristics ◽  
Uniform Theory Of Diffraction ◽  
Moving Vehicles ◽  
Millimeter Wave Band ◽  
Urban Scenario ◽  
Simulation Results ◽  
Street Furniture ◽  
Good Agreement

In this paper, the influence of tree trunks, cylindrical street furniture such as lamp posts, and traffic on ray tracing simulations in an urban scenario is analyzed. Tree trunks and lamp posts are modeled by cylinders and propagation characteristics computed according to the Uniform Theory of Diffraction. The influence of traffic is analyzed by simulations with moving vehicles. In order to get an understanding of the spatial characteristics of the channel, simulations with static and also mobile receivers have been performed, in line with a measurement campaign in the same environment. The simulation results show a good agreement with the measurements.

EXPERIMENTAL AND DENSITY FUNCTIONAL THEORY STUDY ON THz SPECTRA OF 4-NT AND 2, 6-DNT

2007 ◽  
Vol 17 (02) ◽  
pp. 283-291 ◽  
Author(s):  
YUNQING CHEN ◽  
HAIBO LIU ◽  
X. -C. ZHANG
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Diffuse Reflectance ◽  
Diffuse Reflection ◽  
Functional Theory ◽  
Standoff Detection ◽  
Detection Of Explosives ◽  
Related Compounds ◽  
Explosives And Related Compounds ◽  
Good Agreement

Terahertz (THz) spectra of two TNT-related compounds (4-NT and 2, 6-DNT) are investigated using Fourier transform infrared spectroscopy (FTIR, 1.5-20 THz) and THz time-domain spectroscopy (THz-TDS, 0.2-2.5 THz). Density functional theory (DFT) is applied to calculate THz spectra of these two compounds. Transmission, diffuse reflection, and calculated spectra are in good agreement. The measured THz resonance lines from the transmission and diffuse reflectance spectra are assigned based on the DFT simulation. The observed THz signatures imply that THz spectrum has potential for standoff detection of explosives and related compounds (ERCs) in the THz range.

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