PROPERTIES OF HUMIC ACID FRACTIONS IN FOREST HUMUS LAYERS IN BRITISH COLUMBIA

1975 ◽  
Vol 55 (3) ◽  
pp. 381-393 ◽  
Author(s):  
L. E. LOWE ◽  
CARLIEN H. GODKIN
Keyword(s):  
Humic Acid ◽  
Spectral Characteristics ◽  
Ir Absorption ◽  
Total Acidity ◽  
Spectral Absorption ◽  
Vegetative Cover ◽  
Alkali Extraction ◽  
Ir Absorption Spectra ◽  
Absorption Characteristics ◽  
Forest Humus

Thirty-eight chemical and spectral characteristics were determined on humic acid (HA) fractions extracted successively with cold and hot 0.1 N NaOH from F and H horizons under six types of vegetative cover. Some HA properties were significantly affected by extract, with the hot alkali extraction yielding less aromatic and more immature HA fractions. HA properties were relatively unaffected by horizon of origin. Significant differences between sites were observed with respect to H%, S%, atomic H/C, total acidity, molecular weight distribution and IR absorption spectra. Correlation and multiple regression analysis indicated relationships between properties, and suggested that some spectral absorption characteristics may be predicted from chemical composition, and that certain features of composition, related to aromaticity, can be predicted from easily determined spectral characteristics.

scholarly journals Спектральные и структурные характеристики вольфраматов (Lu-=SUB=-1-x-=/SUB=-Eu-=SUB=-x-=/SUB=-)-=SUB=-2-=/SUB=-(WO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (11) ◽  
pp. 2142
Author(s):  
С.З. Шмурак ◽  
В.В. Кедров ◽  
А.П. Киселев ◽  
Т.Н. Фурсова ◽  
И.И. Зверькова ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Structural Characteristics ◽  
Spectral Characteristics ◽  
Orthorhombic Phase ◽  
Luminescence Spectra ◽  
Ir Absorption ◽  
Space Group ◽  
Wetting Ability ◽  
Ir Absorption Spectra ◽  
Wide Range

Investigated are the structure, luminescence, and IR absorption spectra of (Lu1−xEux)2(WO4)3 solid solutions in a wide range of Eu concentrations (0 ≤ x ≤ 1). A sequential replacement of two types of crystalline phases occurs with an increase in Eu concentration. The orthorhombic phase (Pbcn space group) of tungstate solid solutions is observed at 0 ≤ x < 0.5. A monoclinic phase (C2/c space group) arises along with the orthorhombic one in the range of 0.5 ≤ x ≤ 0.8, while at x > 0.8, the solid solution has a monoclinic structure. The correspondence between the structure and spectral characteristics of these compounds is established. A change in the structural state results in a change in luminescence spectra, as well as in the spectra of luminescence excitation of tungstates. The isotherm of water adsorption by the tungstate samples and its effect on their spectral and structural characteristics are studied in view of the wetting ability of (Lu1−xEux)2(WO4)3 solid solutions. It is established that the maximum luminescence under the resonant excitation of Eu3+ ions is observed in the samples with a monoclinic C2/c structure at x ~0.9.

scholarly journals Спектральные и структурные характеристики молибдатов (Lu-=SUB=-1-x-=/SUB=-Eu-=SUB=-x-=/SUB=-)-=SUB=-2-=/SUB=-(MoO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (4) ◽  
pp. 747
Author(s):  
С.З. Шмурак ◽  
В.В. Кедров ◽  
А.П. Киселев ◽  
Т.Н. Фурсова ◽  
И.И. Зверькова ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Monoclinic Phase ◽  
Spectral Characteristics ◽  
Ir Absorption ◽  
Orthorhombic Structure ◽  
Ir Absorption Spectra ◽  
Wide Range ◽  
Crystal Phases ◽  
First Time ◽  
Europium Concentration

AbstractThe structure, the photoluminescence, and IR absorption spectra of solid solutions (Lu_1 ‒ _ x Eu_ x )_2(MoO_4)_3 have been studied over a wide range of europium concentrations (0 ≤ x ≤ 1). It has been found that there is a correlation between the structure and the spectral characteristics of these compounds. Three types of crystal phases are sequentially changed as the europium concentration increases. The photoluminescence and IR absorption spectra of the monoclinic phase with space group P 2_1/ a have been studied for the first time. The glow maximum at a resonant excitation of Eu^3+ ions is shown to be observed in the samples with orthorhombic structure Pba 2 at x ~ 0.8. The samples existing in monoclinic P 2_1/ a phase at x ~ 0.2 demonstrate the maximum luminescence intensity upon excitation in the band with the charge transfer.

A Method Based on Wavelet Transform for Mineral Spectral Characteristics Extraction

2013 ◽  
Vol 718-720 ◽  
pp. 617-620
Author(s):  
Han Bo Li ◽  
Ying Jun Zhao ◽  
Dong Hui Zhang ◽  
Wei Pan
Keyword(s):  
Feature Extraction ◽  
Extraction Method ◽  
Wavelet Decomposition ◽  
Spectral Characteristics ◽  
Spectral Feature ◽  
Experimental Result ◽  
Absorption Feature ◽  
Spectral Absorption ◽  
Feature Extraction Method ◽  
Absorption Characteristics

The basic principle of the wavelet analysis method to extract the mineral spectral absorption characteristics is summarized and different wavelet bases,wavelet decomposition scale extraction effect are analyzed in this paper. Then, the algorithm of mineral spectral absorption characteristics based on wavelet spectral analysis is provided and a large number of experiments are carried out using the spectrums of field rock mineral. Experimental result shows that such a method is less affected by original signal noise and depict the parameters of the mineral spectral absorption feature more precise, which is an ideal spectral feature extraction method compared with the traditional mineral spectral absorption feature extraction method.

scholarly journals Перенос энергии от Ce-=SUP=-3+-=/SUP=- к Tb-=SUP=-3+-=/SUP=- в ортоборатах иттрия и гадолиния, полученных гидротермальным синтезом

2019 ◽  
Vol 61 (1) ◽  
pp. 123
Author(s):  
С.З. Шмурак ◽  
В.В. Кедров ◽  
А.П. Киселев ◽  
Т.Н. Фурсова ◽  
О.Г. Рыбченко
Keyword(s):  
High Efficiency ◽  
Spectral Characteristics ◽  
Hexagonal Lattice ◽  
Dipole Interaction ◽  
Diffraction Spectrum ◽  
Ir Absorption ◽  
X Ray Diffraction ◽  
Space Group ◽  
Ir Absorption Spectra ◽  
Magnitude Increase

AbstractWe studied the structure, IR absorption spectra, the spectral characteristics of photoluminescence and morphology of cerium- and terbium-doped orthoborates of gadolinium and yttrium obtained by hydrothermal synthesis at 200°C, as well as solid solutions of orthoborates on the basis of yttrium, gadolinium, and lutetium with composition RECe_0.01Tb_0.1BO_3 (RE = Lu_0.5Gd_0.39, Lu_0.5Y_0.39, and Y_0.5Gd_0.39). The X-ray diffraction spectrum of yttrium orthoborate Y_1 – _ x  _– _ y Ce_ x Tb_ y BO_3 is described by a hexagonal lattice with space group P 6_3/ m , which, after annealing at 970°C, transforms into a monoclinic lattice with space group C 2/ c . High-temperature annealing of the studied orthoborates leads to a multiple, more than two orders of magnitude, increase in the luminescence intensity of Tb^3+ ions when the samples are excited in the absorption band of cerium ions. This effect is the result of a significant increase in the concentration of Ce^3+ ions in the orthoborates at high temperatures. It is shown that the luminescence of terbium ions is due to energy transfer from Ce^3+ to Tb^3+, which proceeds with high efficiency (∼85%) by the mechanism of dipole-dipole interaction between cerium and terbium.

Near-IR Absorption Spectra for the Buckminsterfullerene Anions: An Experimental and Theoretical Study

1992 ◽  
Author(s):  
Del R. Lawson ◽  
Daniel L. Feldheim ◽  
Colby A. Foss ◽  
Peter K. Dorhoug ◽  
C. M. Elliott
Keyword(s):  
Absorption Spectra ◽  
Theoretical Study ◽  
Ir Absorption ◽  
Near Ir ◽  
Ir Absorption Spectra

Study of the Infrared Absorption Spectra of Some Pyridine Derivatives-Iodine Complexes

1976 ◽  
Vol 30 (2) ◽  
pp. 200-204 ◽  
Author(s):  
F. M. Abdel Kerim ◽  
F. Abou El Fotouh
Keyword(s):  
Complex Formation ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Ir Absorption ◽  
Pyridine Derivatives ◽  
Thermodynamic Constants ◽  
Ir Absorption Spectra ◽  
Infrared Absorption Spectra ◽  
The Stability ◽  
Iodine Complexes

The ir absorption spectra of some pyridine derivatives-iodine complexes were measured in the region 400 to 1400 cm−1 and the results are discussed. The effect of complex formation on the intensities of some of the bands was investigated. The thermodynamic constants of these complexes were calculated. It was found that the stability of the complex depends to a large extent on the electronegativity as well as the position of the substituent on the pyridine nucleus. The structures of formed complexes are discussed.

scholarly journals Fine defective structure of silicon carbide powders obtained from different starting materials

2006 ◽  
Vol 38 (2) ◽  
pp. 177-181 ◽  
Author(s):  
T.V. Tomila ◽  
M.V. Vlasova ◽  
M.G. Kakazey ◽  
K.L. Vyshnyakova ◽  
A.V. Ragulya ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Carbon Black ◽  
Silicic Acid ◽  
Lattice Parameter ◽  
Ir Absorption ◽  
Defective Structure ◽  
Hydrated Cellulose ◽  
Sic Particles ◽  
Acid Gel ◽  
Absorption Characteristics

The fine defective structure of silicon carbide powders obtained from silicic acid-saccharose, aerosil-saccharose, aerosil-carbon black, and hydrated cellulose-silicic acid gel systems was investigated. The relation between IR absorption characteristics and the microstructure of SiC particles obtained from different starting materials was established. The numerical relationship between the lattice parameter a and the frequency ?TO is presented.

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