排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
Shivaji Chongtham Ibetombi Soibam Sumitra Phanjoubam H. N. K. Sarma H. C. Verma 《Hyperfine Interactions》2008,187(1-3):143-148
Mössbauer investigations were carried out at room temperature on the ferrite system Li0.6?+?0.5tFe2.3???1.5tTitSb0.1O4 (0.0 ≤ t ≤ 1.0 in steps of 0.2). The effect of Ti4?+? concentration on the various hyperfine interactions like Isomer shift, quadrupole splitting and internal magnetic field have been studied. The spectra exhibited well-defined Zeeman sextets at low substitution level, corresponding to the A and B sites. The sample with t = 1.0 showed paramagnetic behaviour. The results obtained have been discussed. 相似文献
2.
Ferrites having the general formula Li0.5−0.5xZnxFe2.5−0.5xO4 where 0≤x≤0.6 in steps of 0.2 were prepared by the citrate precursor method. The Curie temperature measured shows a decrease with increasing Zn concentration. Experimental results show that the room temperature initial permeability increases with the increase in the concentration of zinc. The initial permeability has also been studied as a function of frequency in the range of 100 Hz-1 MHz. The real part of initial permeability referred as initial permeability and the imaginary part of initial permeability better known as permeability loss show dispersion with frequency. Possible mechanism contributing to the above processes is discussed. 相似文献
3.
Ibetombi Soibam Sumitra Phanjoubam H. B. Sharma H. N. K. Sarma Chandra Prakash 《Indian Journal of Physics》2009,83(3):285-290
A series of Co substituted lithium zinc ferrite powders with different content of Co (0.00 to 0.1 in steps of 0.02) were prepared
by a novel sol-gel auto combustion process using citric acid. Their spinel structure was confirmed by XRD. The variation in
lattice parameter and density with cobalt concentration was studied which showed an increasing trend. A decreasing pattern
was observed in variation of porosity with increasing Co. Room temperature dielectric constant and resistivity were studied
as a function of composition at 10 KHz. The room temperature dielectric constant decreases with successive addition of Co2+ in the series. The observed variation in dielectric constant has been explained on the basis of space charge polarization
and Koops two layer model. Resistivity is observed to increase with increasing concentration and the observed variation in
resistivity has been explained by Verwey hopping mechanism. 相似文献
4.
Ibetombi Soibam Sumitra Phanjoubam 《Journal of magnetism and magnetic materials》2009,321(18):2779-2782
Li-Zn ferrites substituted with Ni having the compositional formula Li0.4−0.5xZn0.2NixFe2.4−0.5xO4 where x=0.02?x?0.1 in steps of 0.02 were fabricated by the citrate precursor method. This method has been employed to get nanosized particles and good magnetic properties. The spinel phase structure of the prepared ferrites was confirmed by XRD analysis. The effect of Ni concentration on magnetic properties such as saturation magnetization and Curie temperature were investigated. A good knowledge of these magnetic properties is desirable from application point of view. The values observed are large and both quantities were found to decrease with substitution. The saturation magnetizations were found to vary from 78 to 94 emu/gm while the Curie temperature which limits the operating temperature of the system ranges between 563 and 584 °C. Mössbauer data were also recorded at room temperature and the hyperfine parameters like isomer shift, quadrupole splitting and internal magnetic field estimated. The results obtained and mechanisms involved are discussed. 相似文献
5.
B. Soibam L. Chen G. W. Roman G. H. Gunaratne 《The European physical journal. Special topics》2014,223(9):1787-1803
Animals use locomotion to find food, shelter, and escape routes as well as to locate predators, competitors, and mates. Thus, locomotion is related to many behavioral traits, and can be used to characterize these more complex facets of behavior. Exploratory behaviors are random and need to be assessed through stochastic analysis. By comparing ensembles of trajectories from Drosophila and a model animal, we identify a pair of principles that govern the stochastic motion of a specific species. The first depends on local cues and quantify directional persistence, i.e., the propensity of an animal to maintain direction; the second, its attraction to walls, is relevant for exploration in confined arenas. Statistical properties of exploratory activity in several types of arenas can be computed from these principles. A pair of spiral arenas are designed to demonstrate that centrophobicity, or fear of the center of an arena, is not a fundamental feature of exploration. xxxx We provide evidence to show that the decay in an animal’s activity following its introduction into a novel arena is correlated to its familiarity with the arena. We define two measures, coverage and habituation, to quantify familiarity. It is found that the relationship between activity and coverage is independent of the arena size. Finally, we use an analysis of exploration of mutant species to infer that in Drosophila, habituation relies on visual cues. 相似文献
1