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991.
Lead magnesium niobate (PMN) based binary with lead titanate (PT), lead iron niobate (PFN) and lead zinc niobate (PZN) and
ternary with PZN-PT and PFN-PT solid solutions have been synthesized. In depth characterization using X-ray diffraction and
SEM techniques have revealed the major perovskite phase formation. Amongst all the solid solutions, PMN-PZN-PT has given the
highest values of permittivity as 19,740 and 23,700 withT
c as 34°C when sintered at 1080°C and 1180°C respectively on the one hand and on the other, PFN containing solid solutions
exhibited distinct deviation from the relaxor behaviour. 相似文献
992.
MadhuR.N. Singh 《International Journal of Hydrogen Energy》2011,36(16):10006-10012
Palladium selenides, PdSe, Pd3Se and PdSe2 have been prepared by the hydrothermal method and investigated for their structural and electrocatalytic properties toward the oxygen reduction reaction (ORR) using SEM/TEM, XRD, cyclic and linear sweep voltammetries. The crystallites of PdSe and PdSe2 are found to follow tetragonal and orthorhombic crystal structures, respectively. The PdSe electrode in 0.5 M H2SO4 exhibits significantly higher electrocatalytic activity than the Pd3Se or PdSe2 electrode under similar experimental conditions. Further, a change in the palladium/selenium ratio from unity in the catalyst results in low ORR activity. 相似文献
993.
S.P. Nehra M.K. Jangid Subodh Srivastava Anil Kumar Balram Tripathi M. Singh Y.K. Vijay 《International Journal of Hydrogen Energy》2009,34(17):7306
Bilayer thin films of diluted magnetic semiconductor CdTe/Mn have been prepared using vacuum thermal evaporation method at pressure of 10−5 torr. Annealing of bilayer thin films has been performed in atmospheric condition at constant temperature 400 °C for 1 hour. Hydrogenation of as-grown and annealed bilayer thin films has been performed by keeping these in hydrogenation cell. Structural characteristics of as-grown and heat treated thin films have been performed by X-ray diffractometer. Current–voltage characteristics of both as-grown hydrogenated and annealed hydrogenated bilayer thin films have been studied to find out the effect of hydrogenation. Surface topography of as-grown and annealed bilayer thin films has been confirmed by optical microscopy. 相似文献
994.
Polyaniline nanostructures have been formed successfully via a interfacial polymerization method using different organic solvents. These materials were characterized by using IR, UV–vis, TGA, SEM, TEM and AC-impedance spectroscopy. In impedance plot of polyaniline (interfacial polymerization) using different organic solvents, different equivalent circuits with distinct nature of arcs have been observed indicating different distribution ratio indicating diffusion-limited interfacial control of nucleation and growth of polyaniline nanostructures dependent on the different distribution ratio and different rates of transfer of aniline from organic phase to aqueous phase in different solvents. 相似文献
995.
K. K. K. Singh 《Bulletin of Engineering Geology and the Environment》2013,72(1):115-118
Resistivity imaging (RI) survey was carried out along two profiles in the Hingir-Rampur Colliery to assess how far it would be practical to extend the workings in Seam I towards the waterlogged previous workings, whilst leaving at least 60 m of coal between the two sections of mine. In order to corroborate the results of the geophysical survey, two boreholes were drilled along the profiles. Analysis confirmed hard, compact and dry strata between 60 and 146 m depth. 相似文献
996.
Rajendra N. GoyalAuthor Vitae Md. Abdul AzizAuthor VitaeMunetaka OyamaAuthor Vitae Sanghamitra ChatterjeeAuthor VitaeAnoop Raj Singh RanaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,153(1):232-238
A stable layer of gold nano particles (AuNPs) was deposited on the surface of indium tin oxide (ITO) and was used as an electrode for the detection of norepinephrine (NE) by square wave voltammetry (SWV) and cyclic voltammetry (CV). This modified electrode exhibits potent and persistent electron-mediating behavior and a well-defined oxidation peak towards NE was observed. The peak potential of NE was observed at less positive potential with increase in peak current as compared to bare ITO and bare gold electrodes. NE exhibited two quasi-reversible couples at AuNPs modified ITO over the potential range from −0.6 to 0.8 V in phosphate buffer solution (PBS) (pH 7.2). At optimal experimental condition, the catalytic oxidative peak current was responsive with the NE concentrations ranging from 100 nM to 25 μM. The detection limit was found to be 87 nM. Also, the effect of pH revealed that the oxidation of NE at the AuNPs modified ITO involved the transfer of equal number of protons and electrons. The interfering effect of common coexisting metabolites in blood and urine has also been reported. The modified electrode exhibited high stability and reproducibility. A comparison of results with high performance liquid chromatography (HPLC) signalizes a good agreement. 相似文献
997.
Hongtao Jiang Minsky M. Keller S. Hu E. Singh J. DenBaars S.P. 《Quantum Electronics, IEEE Journal of》1999,35(10):1483-1490
InGaN-GaN represents an important heterostructure with applications in electronics and optoelectronics. It also offers a system where we can study the effects of interface roughness, alloy clustering, and the piezoelectric effect. In the paper, we examine how these factors influence the photoluminescence and excitation photoluminescence in InGaN-GaN quantum wells. We examine the Stokes shift as a function of the excitation level and doping and relate the values to the piezoelectric effect and disorder in the system. Detailed comparisons are made with experimental results 相似文献
998.
999.
We have made a systematic study on the diameter dependent spectral features in X-ray diffraction (XRD) and Raman scattering studies of multiwalled carbon nanotubes (MWCNTs) of various diameters in the range 5?100 nm. High resolution transmission electron microscopy (HRTEM) imaging reveals a systematic decrease in the interwall separation from 3.8 Å down to 3.2 Å as the diameter of nanotubes increases from 5.8 nm to 63.2 nm. Analysis of the XRD patterns shows an exponential decrease in d002 interlayer spacing with increasing tube diameter, in close agreement with the HRTEM results. Further, XRD profile line width shows inverse diameter dependence and exponential increase in intensity as the diameter of the MWCNTs increases. Raman spectra of different diameter nanotubes show different evolutions of metallic and semiconducting components in the G-band, as found from spectral deconvolution. The frequency and full width at half maximum (FWHM) of the semiconducting component of the G? band gradually decreases as the tube diameter increases. Ratio of intensities of G? band to D-band first shows a sharp fall as the tube diameter increases from 7 nm to 15 nm and then slowly increases with increasing diameter. On the other hand, G′ mode frequency shows large up shift when average diameter is increased from 7 nm to 15 nm and then saturates for higher diameter tubes. Analysis of Raman and XRD data reveals that the lowest diameter (7 nm) MWCNTs have features similar to those of the single walled nanotubes, while the spectral features are distinctly different for higher diameter MWCNTs due to the interaction among tube walls that is very significant for large diameter MWCNTs. Observed diameter dependence of the spectral features is explained in terms of nanotube curvature and atomic vibrations involving interaction among the walls in MWCNTs. The present study demonstrates the power of XRD for nondestructive evaluation of diameter distribution and interwall separation in MWCNTs with wide range of diameters. 相似文献
1000.
V. J. Rejish Kumar Valsamma Joseph R. Vijai Rosamma Philip I. S. Bright Singh 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(6):790-797
BACKGROUND: A packed bed bioreactor (PBBR) activated with an indigenous nitrifying bacterial consortia was developed and commercialized for rapid establishment of nitrification in brackish water and marine hatchery systems in the tropics. The present study evaluated nitrification in PBBR integrated into a Penaeus monodon recirculating maturation system under different substrate concentrations and flow rates. RESULTS: Instant nitrification was observed after integration of PBBR into the maturation system. TAN and NO2‐N concentrations were always maintained below 0.5 mg L?1 during operation. The TAN and NO2‐N removal was significant (P < 0.001) in all the six reactor compartments of the PBBR having the substrates at initial concentrations of 2, 5 and 10 mg L?1. The average volumetric TAN removal rates increased with flow rates from 43.51 (250 L h?1) to 130.44 (2500 L h?1) gTAN m?3 day?1 (P < 0.05). FISH analysis of the biofilms after 70 days of operation gave positive results with probes NSO 190 ((β ammonia oxidizers), NsV 443 (Nitrosospira spp.) NEU (halophilic Nitrosomonas), Ntspa 712 (Phylum Nitrospira) indicating stability of the consortia. CONCLUSION: The PBBR integrated into the P. monodon maturation system exhibited significant nitrification upon operation for 70 days as well as at different substrate concentrations and flow rates. This system can easily be integrated into marine and brackish water aquaculture systems, to establish instantaneous nitrification. Copyright © 2011 Society of Chemical Industry 相似文献