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991.
Thomas Haensel Markus Reinmöller Pierre Lorenz Wichard J. D. Beenken Stefan Krischok Syed Imad-Uddin Ahmed 《Cellulose (London, England)》2012,19(3):1005-1011
In this report, X-ray induced photoelectron spectroscopy (XPS) measurements of the valence band structure of cellulose and
lignin are combined with a theoretical reconstruction of the spectra based on density functional theory (DFT) calculations.
These calculations involve an analysis of the valence band structures and their respective orbitals in which basic units of
cellulose and lignin are considered. In addition, photoionization cross sections are incorporated for reconstruction of the
XPS spectra. This combination of theoretical calculations and experimental measurements revealed that an emission present
up to 10 eV in the valence band structure is dominated by oxygen rather than by carbon, as reported in literature. Furthermore,
a quantitative elemental analysis shows significant carbon contributions at binding energies above 13 eV. The valence band
analysis supported by DFT provides a powerful basis for a detailed interpretation of spectroscopic data and enables a profound
insight into application relevant processes in future. 相似文献
992.
993.
Lalit Dutta Syed Imran Ahmad Subhra Kanti Mukherjee Sanjeev Mishra Arshad Khuroo Tausif Monif 《Biomedical chromatography : BMC》2013,27(5):622-635
A sensitive, accurate and highly stereoselective assay for the simultaneous determination of venlafaxine (VEN) and its equipotent metabolite, O‐desmethyl venlafaxine (ODV), in human plasma was developed and validated. Analytes were simultaneously extracted from plasma using solid‐phase extraction and detected by tandem mass spectrometry in positive ion mode with a turbo ion spray interface. Deuterium‐labeled VEN and ODV were used as internal standards. Chromatographic separation was performed on a Chiral AGP column, using a time programmed gradient flow with a total run time of 16 min. The method has a lower limit of quantitation of 0.60 ng/mL. The assay was linear over a range 0.60–300.00 ng/mL for both the enantiomers of VEN and ODV, respectively, with coefficient of correlation > 0.99. The extraction recoveries were >77.0% on an average for all the four analytes. The analytes were found stable in plasma through three freeze (?15 °C) and thaw cycles and under storage at room temperature for 8 h, and also in mobile phase at 10 °C for 54 h. The method has shown good reproducibility, with intra‐ and inter‐day variation coefficients < 9%, for all the analytes, and has proved to be very reliable for analysis of VEN and its metabolite in clinical study samples. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
994.
The scattering of electromagnetic plane wave from a coated nihility circular cylinder placed in chiral metamaterial is investigated. The nihility cylinder is coated with chiral or chiral-nihility metamaterial and the medium hosting the coated cylinder is also considered as chiral or chiral-nihility metamaterial. The vector wave equation is used to find out the solution for the fields scattered from the concentric chiral ciruclar cylinders immersed in chiral metamaterial. Inner chiral cylinder is reduced to nihility cylinder taking permittivity and permeability approaching to zero with chirality parameter equal to zero. Coated perfect electric conductor (PEC)/perfect magnetic conductor (PMC) are obtained by taking very large value of permittivity/permeability of the inner cylinder. Numerical results for fields reflected from coated nihility cylinder are compared with those obtained for coated PEC/PMC cylinder. Our results for the special case of dielectric coated nihility/PEC cylinders in free space are shown to be in agreement with already published results thus validating the scheme of analysis. 相似文献
995.
We demonstrate that magnetic dipole transitions provide an additional degree of freedom for engineering emission spectra. Without the need for a high-quality optical cavity, we show how a simple gold mirror can strongly tune the emission of trivalent europium. We exploit the differing field symmetries of electric and magnetic dipoles to selectively direct the majority of emission through each of three major transitions (centered at 590, 620, and 700 nm), and present a model that accurately predicts this tuning from the local electric and magnetic density of optical states. 相似文献
996.
Syed M. BukhariJavier B. Giorgi 《Solid State Ionics》2011,194(1):33-40
A new series of perovskite materials with formula Sm0.95Ce0.05Fe1 − xNixO3 − δ (0 ≤ x ≤ 0.10) has been prepared by sol-gel combustion via a citrate precursor route. X-ray diffraction data showed that materials prepared by this method had a single orthorhombic phase belonging to the Pnma (62) space group. The study of powders sintered in air and in reducing atmospheres reveals that these materials do not show phase separation in air (up to 1350 °C) nor under 5% v/v H2/N2 (up to 700 °C), but a phase separation of Sm2O3 does occur at and above 800 °C under 5% v/v H2/N2 without deterioration of the perovskite phase. The surfaces of all the powders (fresh, in-situ reduced and ex-situ reduced) were Sm rich, and multiple oxidation states for Fe were observed. XP analysis of in-situ reduced samples (800 °C and above) shows that metallic Fe forms in all nickel doped materials except x = 0.07. The surface oxygen vacancies and percentages of lattice and adsorbed oxygen for this series of Ni doped materials were determined and the oxygen recapturing ability is explained in terms of the multiple oxidation states of Fe. 相似文献
997.
There has been lots of interest in exploring the thermodynamic properties at the horizon of a black hole spacetime.It has been shown earlier that for different ... 相似文献
998.
A new highly selective, reversible, chromogenic, and fluorogenic chemosensor (4) based on thiazole-coumarin moieties for quantification of copper ions in aqueous-DMSO was designed and synthesized. The mechanism of fluorescence was based on ICT, which was modified by the introduction of an electron-donating diethylamino group making it chromogenic and increasing the binding affinity. The selectivity toward copper ions was not affected by the presence of representative alkali metals, alkali earth metals, or other transition metals. 相似文献
999.
Syed Qaiser Shah Muhammad Rafiullah Khan 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):357-362
99mTc ≡ N-Pazufloxacin dithiocarbamate (99mTc ≡ N-PZN) complex was synthesized through the [99mTc ≡ N]2+ core and its aptness was radiochemically and biologically evaluated in terms of radiochemical purity (RCP) in saline, in
vitro stability in serum, in vitro bacterial uptake and percent in vivo uptake in male Wister rats (MWR) artificially infected
with alive and heat killed Escherichia coli (E. coli). The 99mTc ≡ N-PZN complex showed more than 90% RCP up to 4 h after reconstitution in normal saline at room temperature with a maximum RCP
value of 98.40 ± 0.28% (at 30 min). At 37 °C in serum the complex showed stable behaviour up to 4 h with the appearance of
15.95% undesirable by products within 16 h of the incubation. The complex showed saturated in vitro binding with E. coli with a maximum uptake of 74.25 ± 0.50% (at 90 min). Normal biodistribution behaviour was noted with a sixfold higher accumulation
in the muscle of the MWR, artificially infected with live E. coli as compared to the MWR infected with heat killed E. coli, inflamed and normal muscle. The high RCP in saline, elevated in vitro stability in serum, saturated in vitro binding with
E. coli and the sixfold higher accumulation in the infected (live) muscle of the MWR as compared to the inflamed and normal muscle,
recognized the aptness of the 99mTc ≡ N-PZND complex as a prospective E. coli in vivo infection radiotracer. 相似文献
1000.
Syed?Qaiser?ShahEmail author Muhammad?Rafiullah?Khan 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):411-415
Extraction of microamounts of cesium by nitrobenzene solutions of sodium dicarbollylcobaltate (Na+B−), potassium dicarbollylcobaltate (K+B−) and rubidium dicarbollylcobaltate (Rb+B−) in the presence of polypropylene glycol PPG 425 (L) has been investigated. The equilibrium data have been explained assuming
that the complex species ML+ (M+ = Na+, K+, Rb+, Cs+; L = PPG 425) are present in the organic phase. The stability constants of the cationic complex species ML+ (M+ = Na+, K+, Rb+) in nitrobenzene saturated with water have been determined; they were found to increase in the series of Rb+ < K+ < Na+. 相似文献