摘要:

Infrared spectra of Neyveli Lignite samples at different depths from mine cut-I and II were recorded in the region 4000–200 cm−1. Probable assignments of the bands were made with respect to the components present in the samples. The Lignite samples collected at 80m, 82m, 87m and 90m from minecut-I and 52m, 56m and 58m from minecut - II shows distinctly a band at 1500cm−1indicating that these belong to pleistocene—miocene period, while the absence of this band in the samples at deeper depths 92m and 94m from minecut-I and 62m and 65 m from minecut-II indicate that these belong to Oligocene to Palaeocene period.

ISSN:0038-7010    

DOI:10.1080/00387019108018157

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The synthetic tetrapeptide acetyl - tyrosyl - valyl - tyrosyl - alanine (Ac-YVYA-OH) has been studied as a simplified model of iron or copper binding sites of transferrins. In acidic medium pH < 2.5, the cations interact with the alanyl C terminal carboxylate. In neutral or alkaline medium a strong interaction appears between the tetrapeptide and ferrous cations, involving peptidic bonds.

ISSN:0038-7010    

DOI:10.1080/00387019108018158

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The vibrations of planar A2BC type molecules with C2vsymmetry are analysed in terms of Cartesian co-ordinates. Analytical expressions for the six normal mode frequencies are derived from the Lagrangian formalism and compared with previous results. Optimized force constants for formaldehyde, thioformaldehyde and their deuterated derivatives, as well as three carbonyl halide molecules, are calculated and briefly discussed.

ISSN:0038-7010    

DOI:10.1080/00387019108018159

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Zeolites of NaA and NaY types were treated with hydrochloric acid. It was found that increase of the solution acidity leads to a decationizing of the zeolites. At the same time a decrease of zeolite crystallinities was observed. For the latter, both an infrared method and X-ray diffraction were employed. The degree of crystallinity as found by the IR method is systematically higher when compared to the X-ray method, but a linear relationship exists between these values. The lowering of intensities of diffraction lines with the decrease of crystallinity is explained by changes in the electron density caused by the process of decationizing and formation of defects in the zeolite structures.

ISSN:0038-7010    

DOI:10.1080/00387019108018160

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The NMR1H and IR spectra of ethyl esters of two β-alkyl and β-aryl substituted of β-aminoacrylic acid have been measured. The results are evidence of the strong intramolecular hydrogen bond between amino group and carbonyl oxygen. The activation energy of about 20 kcal/mol was obtained for the internal rotation around C-N bond.

ISSN:0038-7010    

DOI:10.1080/00387019108018161

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

FTIR spectroscopy has been used to characterize a bituminous coal from the Pozo María Luisa in Asturias (Spain) and to analyze the effects of varying the time (from 0 to 4 days) of oxidation at 270° C. The goal is to obtain information on aromaticity, non aromatic hydrogens and various functional groups.

ISSN:0038-7010    

DOI:10.1080/00387019108018162

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Laser excited atomic fluorescence spectrometry (LEAFS) with a N2-laser pumped dye laser with a Shimadzu GFA-4A graphite furnace is used to determine thallium in solid samples of bovine liver and tomato leaves. The linear range for thallium under the studied conditions is 0–50 pg. The instrumental LEAFS detection limit for thallium was 100 fg. Solid samples from National Institute of Standards and Technology were analyzed by this method. The content of thallium in bovine liver and tomato leaves was 0.059 and 0.055 μg/g with relative standard deviation of 12.5% and 15.8% respectively; the results obtained are within the reported limit.

ISSN:0038-7010    

DOI:10.1080/00387019108018163

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Emission bands of the (C-X) and (D-X) systems of HgX (X=Cl,Br,I) radicals and atomic mercury lines during transitions from various excited levels to lower levels have been observed due to collisions of N+and N2+ions and HgX2molecules. Emission cross-sections have been determined at different laboratory kinetic energies of the projectile ions by using the integrated intensity of emission, the HgX2vapor densities, charged particle densities and the interaction length between the charged particles and the mercury halide vapors.

ISSN:0038-7010    

DOI:10.1080/00387019108018164

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Infrared emission spectra emitted by high luminosity infrared pyrotechnics have been observed remotely using the Fourier transform infrared spectroscopy. The primary purpose of the study is to determine infrared spectral radiance distribution, their time—resolved spectra and integrated emission energy. The spectra have been recorded between 4000 – 800cm−1region with spectral resolution of 4cm−1. The study is very important for many applications.

ISSN:0038-7010    

DOI:10.1080/00387019108018165

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The presence of circulating free DNA in the sera of cancer patients has been reported by different authors. Moreover, a hypothetical relationship between the DNA level and different stages of the disease has also been suggested. In this work, the free serum DNA level in various cancer patients was measured and consistent results with the reported data were found. (1,4) To assess the possible mechanism for the release of this fraction and to explain the high levels observed in cancer patients levels of the bivalent intracellularcation, magnesium were determined. Further to relate the process to the antioxidative mechanism of the cell membrane also selenium levels were measured simultaneously. The serum free DNA and the magnesium concentration of the patients before treatment were significally higher and the selenium levels lower than the control group. After appropriate the rapy the magnesium levels were found to decline while the high free DNA and low selenium values still persisted. These findings imply that the membrane stability and permeability is impaired due both to the neoplastic changes and later to the effect of chemotherapeutic agents with the result that intracellular material is released into the circulation.

ISSN:0038-7010    

DOI:10.1080/00387019108018166

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor