432 research outputs found

    Magnetic properties of Hydrogenated Li and Co doped ZnO nanoparticles

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    The effect of hydrogenation on magnetic properties of Zn0.85Co0.05Li0.10O nanoparticles is presented. It was found that the sample hydrided at room temperature (RT) showed weak ferromagnetism (FM) while that hydrided at 400oC showed robust ferromagnetism at room temperature. In both cases reheating the sample at 400oC in air converts it back into paramagnetic state (P) completely. The characterization of samples by X-ray and electron diffraction (ED) showed that room temperature ferromagnetism observed in the samples hydrogenated at RT is intrinsic in nature whereas that observed in the samples hydrogenated at 400oC is partly due to the cobalt metal clusters.Comment: 10 pages, 3 figure

    Geometrical dynamics of Born-Infeld objects

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    We present a geometrical inspired study of the dynamics of DpDp-branes. We focus on the usual nonpolynomial Dirac-Born-Infeld action for the worldvolume swept out by the brane in its evolution in general background spacetimes. We emphasize the form of the resulting equations of motion which are quite simple and resemble Newton's second law, complemented with a conservation law for a worldvolume bicurrent. We take a closer look at the classical Hamiltonian analysis which is supported by the ADM framework of general relativity. The constraints and their algebra are identified as well as the geometrical role they play in phase space. In order to illustrate our results, we review the dynamics of a D1D1-brane immersed in a AdS3×S3AdS_3 \times S^3 background spacetime. We exhibit the mechanical properties of Born-Infeld objects paving the way to a consistent quantum formulation.Comment: LaTex, 20 pages, no figure

    Genetic Evaluation and AMMI Analysis for Salinity Tolerance in Diverse Wheat Germplasm

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    Soil salinity is one of the major environmental constraints in increasing agricultural crop production, especially wheat production in India. Screening of diverse germplasm in representative growing conditions is prerequisite for exploring traits with stable expression imparting salinity tolerance. A study was undertaken during 2011–2012 for characterizing wheat germplasm in three environments representing growing conditions of crop in Northern parts of India, estimating inter-relationship among traits and evaluating stability of trait conferring salinity tolerance. Significant value of mean square for observed trait across the environments signified presence of large variability in genotypes. Significant yield reduction was recorded in almost all genotypes in saline environment compared to non-saline condition. Ratio of potassium and sodium ion in leaf tissue (KNA); a key salt tolerance traits was found to be significantly correlated with biomass, SPAD value and plant height. Due to the presence of significant genotype × environment interaction (G × E) for KNA, additive main effect and multiplicative interaction (AMMI) model was utilized to study stability of KNA among genotypes and environments. IPCA1 and IPCA2 were found to be significant and explained more than 99 per cent of variation due to G × E. KRICHAUFF was having maximum trait value with specific adaptation while DUCULA 4 and KRL 19 were having general adaptability. AMMI2 biplot revealed high stability of Kharchia 65 and KRL 99 across environments. E1 (timely sown, non-saline soil) recorded maximum site mean while E2 (timely sown, sodic soil) was having minimum interaction with genotypes (AMMI1 = 1.383). Thus, our studies suggest that AMMI model is also useful for estimating adaptability of traits other than yield utilized for breeding salt tolerant wheat varieties

    Electronic Structure And Vibrational Analysis Of Norclozapine (8-Chloro-11-Piperazine-1-Yl-5H-Dibenzo[B,E] [1,4]Diazepine)

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    Introduction: N-desmethyl clozapine or norclozapine is a benzodiazepine substituted with chloro and piperazino groups which is a major metabolite of clozapine; a potent and selective 5-HT2C serotonin receptor antagonist. It has a role as a metabolite, a delta-opioid receptor agonist, and a serotonergic antagonist. It is a dibenzodiazepine, a member of piperazines, and an organochlorine compound. Methods: The structure and the ground state energy of the molecules under investigation have been analyzed employing the DFT / B3LYP level. The optimized geometry and their properties such as equilibrium energy, frontier orbital energy, dipole moment, and vibrational frequencies have been used to understand the activity of Norclozapine. Results: The calculated highest occupied molecule orbital or HOMO and the lowest unoccupied molecular orbital or LUMO energies show that charge transfer within the molecule. The vibrational spectra of IR and Raman have been interpreted with the help of the B3LYP level of theory with the 6-31G basis set from the Density function theory. Conclusions: The optimized structural parameters such as bond lengths, and bond angle were determined at B3LYP level theory with a 6-31G basis set. Simulation work of Norclozapine is in process. Simulation report of Norclozapine we will report very soon. &nbsp

    Magnetic Behavior of Manganese-Doped ZnSe Quantum Dots

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    Magnetic properties of manganese-doped ZnSe quantum dots with the size of approximately 3.6 nm are investigated. The amount of Mn in the ZnSe quantum dots has been varied from 0.10% to 1.33%. The doping level in the quantum dots is much less than that used in the precursor. The co-ordination of Mn in the ZnSe lattice has been determined by electron paramagnetic resonance (EPR). Two different hyperfine couplings 67.3×10−4 and 60.9×10−4 cm−1 observed in the EPR spectrum imply that Mn atoms occupy two distinct sites; one uncoordinated (near the surface) and other having a cubic symmetric environment (nanocrystal core), respectively. Photoluminescence measurements also confirm the incorporation of Mn in ZnSe quantum dots. From the Curie-Weiss behavior of the susceptibility, the effective Mn-Mn antiferromagnetic exchange constant (J1) has been evaluated. The spin-glass behavior is observed in 1.33% Mn-doped ZnSe quantum dots, at low temperature. Magnetic behavior at a low temperature is discussed

    Chiral Bosons Through Linear Constraints

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    We study in detail the quantization of a model which apparently describes chiral bosons. The model is based on the idea that the chiral condition could be implemented through a linear constraint. We show that the space of states is of indefinite metric. We cure this disease by introducing ghost fields in such a way that a BRST symmetry is generated. A quartet algebra is seen to emerge. The quartet mechanism, then, forces all physical states, but the vacuum, to have zero norm.Comment: 9 page
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