Diffuse-Reflectance Spectra of Rare-Earth Oxides

1967 ◽  
Vol 21 (3) ◽  
pp. 167-171 ◽  
Author(s):  
William B. White
Keyword(s):  
Rare Earth ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Diffuse Reflectance Spectroscopy ◽  
Rare Earth Oxides ◽  
Rare Earth Ions ◽  
Reflectance Spectra ◽  
Solid Materials ◽  
Diffuse Reflectance Spectra ◽  
Structural Types

Diffuse-reflectance spectra are reported for 11 rare-earth oxides of various structural types over the spectral range of 225–2700 mμ. These spectra, particularly in the near infrared, permit the use of diffuse-reflectance spectroscopy to identify rare-earth ions in solid materials.

scholarly journals Analysis of spectroscopic diffuse reflectance plots for different skin conditions

2010 ◽  
Vol 24 (5) ◽  
pp. 467-481 ◽  
Author(s):  
Shanthi Prince ◽  
S. Malarvizhi
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Skin Diseases ◽  
Diffuse Reflectance Spectroscopy ◽  
Spectral Characteristics ◽  
Reflectance Spectra ◽  
Diffuse Reflectance Spectra ◽  
Spectral Curves ◽  
Skin Conditions

Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteristics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band. The purpose of this study is to determine whether visible/near-infrared diffuse reflectance spectroscopy can be used to non-invasively characterize skin diseasesin vivo.An optical fiber spectrometer is set up for obtaining diffuse reflectance spectra. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in diffuse reflectance spectra.For the present study different skin conditions like – warts, vitiligo, thrombus (due to injury) and angioma are chosen. The spectral data obtained from the scan are plotted and compared. More or less, the shapes of the spectral curves for various skin conditions resemble. In order to characterize and differentiate different diseased state spectral analysis based on Ratio analysis, Student'st-tests and difference plot are carried out.Based on the analysis the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the normal tissue from the one affected by disease.

Method for Obtaining Improved Diffuse Reflectance Spectra in the near Infrared

1967 ◽  
Vol 21 (5) ◽  
pp. 339-342 ◽  
Author(s):  
A. F. Sklensky ◽  
J. H. Anderson ◽  
K. A. Wickersheim
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Reflectance Spectra ◽  
Diffuse Reflectance Spectra

Fractional Derivative Analysis of Diffuse Reflectance Spectra

1998 ◽  
Vol 52 (6) ◽  
pp. 840-846 ◽  
Author(s):  
Joseph M. Schmitt
Keyword(s):  
Fractional Derivative ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Reflectance Spectra ◽  
Background Concentration ◽  
Frequency Noise ◽  
Mathematical Tool ◽  
Diffuse Reflectance Spectra ◽  
Derivative Spectroscopy ◽  
Derivative Analysis

Fractional differentiation is introduced as a mathematical tool for analysis of diffuse-reflectance spectra. The quantity —log10 e/R dqR/ dλ q, where R is the measured reflectance and q is a real number greater than zero, is defined and shown to have properties analogous to those of the integer-order derivatives of log10(1/ R) that are commonly employed in near-infrared spectroscopy. Like conventional derivative spectroscopy, fractional derivative spectroscopy (FDS) is effective for reducing baseline variations and separating overlapping peaks. FDS has the additional benefit that it enables the user to control the weight given to the slope and curvature of spectral features and, therefore, provides greater flexibility in the choice of wavelengths for regression. FDS also enables the user to adjust the relative sensitivities of the regressions to constant offsets and high-frequency noise. An example is given in which FDS is used to estimate the concentration of hemoglobin in a scattering liquid containing a large background concentration of water.

scholarly journals Photolumineszenz und sensibilisierte IR-Emission der dreiwertigen Seltenen Erden in Ca3La2Te2O12

1985 ◽  
Vol 40 (7) ◽  
pp. 699-705 ◽  
Author(s):  
H.-D. Autenrieth ◽  
B. Kottmann ◽  
S. Kemmler-Sack
Keyword(s):  
Rare Earth ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Infrared Region ◽  
Host Lattice ◽  
Rare Earth Ions ◽  
New Host ◽  
Trivalent Rare Earth ◽  
Near Infrared Region ◽  
Ir Emission

By activation of the new host lattice Ca3La2Te2O12 with trivalent rare earth ions an emission in the visible (Ln3+=Sm, Eu, Tb, Dy, Ho, Er, Tm) or near infrared region (Nd, Ho, Er, Tm, Yb) is observed. Energy transfer from Nd3+ to Yb3+ , from Er3+, Yb3+ to Ho3+ and from Yb3+ to Tm3+ has been found to occur. The excitation, emission and diffuse reflectance spectra are analyzed.

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