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991.
M. Muthu Rama Krishnan Pratik Shah Mousumi Pal Chandan Chakraborty Ranjan Rashmi Paul Jyotirmoy Chatterjee Ajoy K. Ray 《Micron (Oxford, England : 1993)》2010,41(4):312-320
This article presents a quantitative approach for the characterization of normal oral mucosa (NOM) in respect to thickness and textural properties of its entire epithelial layer. Histological images of oral mucosa depict that both thickness and tissue architecture at cellular and tissue level undergo change, as mucosa converts from normal to precancerous or cancerous state. In this study the thickness and fractal dimension of the mucosal epithelium of NOM and oral sub-mucous fibrosis (OSF) condition have been computed using 83 normal and 29 OSF images of oral mucosa. The result shows significant delineation between NOM and OSF in respect of both the epithelial thickness (in μm) and fractal dimensions. This quantitative characterization of oral epithelium will be of immense help for oral onco-pathologists and researchers to assess the biological nature of normal and diseased (OSF) mucosa with higher accuracy. Moreover, further differential applications may enable them to find out newer accurate quantitative diagnostic procedures to that of the usual histopathological gold standard for the assessment of malignant potentiality. 相似文献
992.
Nairwita Mazumder Subenoy Chakraborty 《The European Physical Journal C - Particles and Fields》2010,70(1-2):329-334
In this paper, we examine the validity of the generalized second law of thermodynamics of the universe bounded by the event horizon in brane-world gravity. Here we consider a homogeneous and isotropic model of the universe in the one case where it is filled with a perfect fluid and in another case where a holographic dark energy model of the universe has been considered. 相似文献
993.
Several matrix methods have been developed for studying polarization properties of light. Jones was the first to apply the matrix method to the study of polarization optics. In Jones matrix formalism the polarized wave field is represented by 2-element column matrix known as Jones Vector and the polarization device encountered by light is represented by a 2×2 matrix, known as the characteristic Jones matrix of the device. Mueller introduced a new matrix method where the wave field is represented by a 4-dimensional vector. The elements of the vector are the Stokes parameters of the beam. In Mueller matrix formalism the optical device is represented by a 4×4 real matrix known as ‘Mueller Matrix’ of the device. The use of coherency matrix also proves to the useful in the study of partially polarized light. Pauli spin matrices have been used to unify the different matrix treatments of polarization optical phenomena. The present article is an attempt to unify the analysis of polarization phenomena using Dirac matrices used by Dirac in quantum mechanics. We have however redefined the set of Dirac matrices in terms of the Kronecher product of Pauli spin matrices. 相似文献
994.
Shuvendu Chakraborty Ujjal Debnath 《International Journal of Theoretical Physics》2010,49(8):1693-1698
We have considered N-dimensional Einstein field equations in which four-dimensional space-time is described by a FRW metric and that of extra
dimensions by an Euclidean metric. We have supposed that the higher dimensional anisotropic universe is filled with only normal
scalar field or tachyonic field. Here we have found the nature of potential of normal scalar field or tachyonic field. From
graphical representations, we have seen that the potential is always decreases with field φ increases. 相似文献
995.
Asit Banerjee Tanwi Bandyopadhyay Subenoy Chakraborty 《General Relativity and Gravitation》2008,40(8):1603-1607
A model of an emergent universe is obtained in brane world. Here the bulk energy is in the form of cosmological constant,
while the brane consists of a fluid satisfying an equation of state of the form , which is effectively a radiation equation of state at high energies. It is shown that with the positive bulk cosmological
constant, one of our models represents an emergent universe. 相似文献
996.
Low-temperature neutron diffraction measurements were carried out on a powder sample of the compound La0.75Sr0.25CrO3 in order to elucidate its magnetic structure. Rietveld analysis of the neutron diffraction data, as a function of temperature, showed that it possesses a G-type antiferromagnetic alignment of Cr spins at all temperatures below 300 K. Down to the lowest achievable temperature, viz. 17 K, the Cr site moments were found to be the weighted average of the 75% Cr3+ and 25% Cr4+ spin-only ionic moments. At 17 K, the Cr site moment was 2.71(5) μB/Cr ion. There is no observable change in the Cr–O bond lengths as a function of temperature. The tilt angles of the CrO6 octahedra marginally increase with decreasing temperature. 相似文献
997.
Debapriya Chakraborty 《Physics letters. A》2008,372(33):5462-5466
A generalized boundary condition in the Stokes regime is developed for modeling wall bounded flows of fluids with homogeneous internally rotating structures. The governing equations are solved to obtain a universal scaling behavior of the micro-rotation boundary condition at the walls. These observations are supported by molecular dynamics simulation predictions. 相似文献
998.
Ashok Rao Bhasker Gahtori S.K. Agarwal Tirthankar Chakraborty Chandan Kumar Sarkar Anirban Das 《Physica C: Superconductivity and its Applications》2009,469(1):64-69
Polycrystalline samples of MgB2 superconductor (Mn-doped as well as pristine) were investigated by measurements of the electrical resistivity, magneto-resistance in the temperature range of 4–300 K. All the samples show metallic behaviour. It is observed that the upper critical field slightly decreases with Mn concentration. Specific heat measurements were performed with field as well as without field. For comparison, we also prepared one Fe-doped and specific heat measurements were also carried out on this sample. It is observed that the jump in specific heat decreases with increase in Mn content. 相似文献
999.
The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper. 相似文献
1000.
In this work, the Cosmic No-Hair Conjecture (CNHC) has been examined in the context of Randall–Sundrum type-II braneworld
model. Instead of considering the usual anti-de Sitter bulk, a general form of the bulk matter has been taken into account.
The effective Einstein equation on the brane has been derived. In order to obey the CNHC, some restrictions are obtained on
the quadratic correction term as well as on the projected part of the bulk energy momentum tensor on the brane. It is found
that for the validity of the conjecture on the brane, the bulk matter need not satisfy the standard energy conditions. 相似文献