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131.
Neeraj Dwivedi Sushil Kumar Hitendra K. Malik C. Sreekumar Saurabh Dayal C.M.S. Rauthan O.S. Panwar 《Journal of Physics and Chemistry of Solids》2012,73(2):308-316
Copper containing diamond like carbon (Cu-DLC) thin films were deposited on various substrates at a base pressure of 1×10?3 Torr using a hybrid system involving DC-sputtering and radio frequency-plasma enhanced chemical vapor deposition (RF-PECVD) techniques. The compressive residual stresses of these films were found to be considerably lower, varying between 0.7 and 0.94 GPa and Cu incorporation in these films improve their conductivity significantly. Their structural properties were studied by Raman spectroscopy, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction techniques that clearly revealed the presence of Cu in the DLC structure. Raman analysis yields that Cu incorporation in DLC enhances the graphite-like sp2 bonding. However, the sp2 bonding was found to continuously reduce with the increasing C2H2 gas pressure, this may be due to reduction of Cu nanocrystal at the higher pressure. FTIR results inferred various bonding states of carbon with carbon, hydrogen and oxygen. In addition, hydrogen content and sp3 and sp2 fractions in different Cu-DLC films were also estimated by FTIR spectra and were correlated with stress, electrical, optical and nano-mechanical properties of Cu-DLC films. The effect of indentation load (4–10 mN) on nano-mechanical properties of these films was also explored. 相似文献
132.
Shambhu D. Varma 《International journal of quantum chemistry》1981,20(2):479-484
Based on in vitro culture studies, it has been proposed that the photochemical generation of superoxide in the intraocular chambers provides a significant cataractous insult. Rat lens when maintained in medium generating excessive O is damaged as indexed by deterioration of the cation pump. If O levels are low (ambient levels), peroxidative degradation of lipids has been observed. These reactions are intuitively deleterious to tissue physiology and may contribute to the manner through which light may be toxic to lens in the long run, giving rise to senile cataracts. It was interesting to note that these deleterious reactions could be attenuated greatly by physiological levels of ascorbic acid. The significance of these in vitro studies to the in vitro situatiion as offered by the diurnal habitat of mankind remains yet to be known, but studies simulating such situation in experimental animal models are in progress. 相似文献
133.
134.
Xiaobo Chen Per-Anders Glans Xiaofeng Qiu Smita Dayal Wayne D. Jennings Kevin E. Smith Clemens Burda Jinghua Guo 《Journal of Electron Spectroscopy and Related Phenomena》2008
The electronic origins of the visible-light response of N-, C- and S-doped TiO2 have been studied using X-ray absorption, X-ray emission, and X-ray photoelectron spectroscopies. New electronic states are observed in the bulk band gap, above the valence band edge of pure TiO2, which can be directly related to the visible-light absorption of the N-, C- and S-doped TiO2 materials. 相似文献
135.
Summary: The solvent/non-solvent interchange across the fiber surface affects the morphology of the fiber in various ways. In this paper, simulations have been performed to elucidate the diverse morphologies obtained during spinning of polymer fibers under the presence of a non-solvent. The proposed model deals with a ternary system derived from Cahn-Hilliard equation, alternatively known as Time Dependent Ginzburg Landau-TDGL model B equation, involving the spatio-temporal evolution of concentration order parameter. Depending on the coexistence region of the ternary phase diagram, various fiber morphologies including concentric bands, internal microfibrillar structures, and porous structures were discerned. It may be inferred that the formation of the aforementioned diverse morphologies is a direct consequence of the initial conditions of the starting mixtures in a manner governed by the relative rates of solvent/non-solvent exchange and the dynamics of phase separation. 相似文献
136.
We propose a new theoretical scheme for the binary phase diagrams of crystal-liquid crystal mixtures by a combination of a phase field model of solidification, the Flory-Huggins theory for liquid-liquid mixing and Maier-Saupe-McMillan (FH-MSM) model for nematic and smectic liquid crystal orderings. The phase field theory describes the crystal phase transition of anisotropic organic crystal and/or side chain liquid crystalline polymer crystals while the FH-MSM model explains isotropic, nematic and smectic-A phase transitions. Self-consistent calculations reveal several possible phase diagram topologies of the binary crystal-liquid crystal mixtures. The calculated phase diagrams were found to accord well to the reported experimental results. 相似文献
137.
Sampat Dayal Jha 《Colloid and polymer science》1954,137(2-3):162-163
138.
We have found that the composition, Bi1.2Pb0.33Sr1.54Ca2.06Cu3Oy which is comparatively poorer in Bi and Sr with respect to 2:2:2:3, a single-phase 110 K superconductor can be obtained. Such polycrystalline samples have been synthesized by two different methods. The synthesized samples have been characterized by their X-ray diffraction patterns and temperature dependence of DC electrical resistivity and AC susceptibility down to 20 K have been carried out. The samples have been identified as having single phase with a sharp transition. The results of their AC susceptibility have been analysed using Clems critical state model. The effective volume fraction of the grains and the temperature dependence of the intergranular current density have been estimated. 相似文献
139.
Vinay Dayal 《Experimental Mechanics》1992,32(3):197-202
The measurement of wave velocity in a sample requires an accurate determination of the sample thickness at the points of interrogation.
The theory of an automated technique is presented. In its application, the thickness of the sample is first calculated by
the knowledge of the wave velocity in the immersion fluid. This thickness is then used to calculate the wave velocity in the
sample. The results of the application of the technique to isotropic and anisotropic materials are presented. 相似文献
140.