| 1. |
- Adler, SS, et al.
(författare)
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Double helicity asymmetry in inclusive midrapidity pi(0) production for polarized p+p collisions at root s=200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:20: 202002
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at roots=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.
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| 2. |
- Wei, Tzu-Chieh, et al.
(författare)
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Quantifying multipartite entanglement
- 2004
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Ingår i: Quantum communication, meaurement and computing. - : AIP. - 0735402167 ; , s. 241-244
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Konferensbidrag (refereegranskat)abstract
- A natural way of quantifying the degree of entanglement for a pure quantum state is to compare how far this state is from the set of all unentangled pure states. This geometric measure of entanglement is explored for bipartite and multipartite pure and mixed states. It is determined analytically for arbitrary two-qubit mixed states and for generalized Werner and isotropic states. It is also applied to certain multipartite mixed states. including two multipartite bound entangeled states discovered by Smolin and Dur. Moreover, the geometric measure of entanglement is applied to the ground state of the Ising model in a transverse magnetic field. From this model the entanglement is shown to exhibit singular behavior at the quantum critical point.
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| 3. |
- Zakaria, A.K.M., Asgar, M.A., Ahmed, F.U., Yunus, S.M., Azad, A.K., Paranjpe, S.K., Das, A.
(författare)
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Studies of Mn0.5Cr0.5Fe2O4 ferrite by neutron diffraction at different temperatures in the range 768K ³ T ³ 13K
- 2002
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Ingår i: Indian Journal of Pure & Applied Physics. ; 40, s. 46-53
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Das, D. K., et al.
(författare)
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Effect of Al content on microstructure and cyclic oxidation performance of Pt-aluminide coatings
- 2002
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Ingår i: Oxidation of Metals. - 0030-770X .- 1573-4889. ; 57:3-4, s. 245-266
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Tidskriftsartikel (refereegranskat)abstract
- The effect of Al content, i.e., the amount of Al picked up during aluminizing, on the microstructure and cyclic oxidation properties of Pt-aluminide coatings has been investigated. The cast Ni-base superalloy CM-247 was used as the substrate material and a single-step, high-activity pack aluminizing process was used to produce the Pt-aluminide coatings. The Al content of these coatings was varied by using packs with different compositions of the Al source. Pt-aluminide coatings having three different Al contents, namely 6.5, 16, and 21 mg cm-2, were evaluated for their cyclic oxidation resistance at 1200°C in air. It was found that the Pt-aluminide coatings, irrespective of their Al contents, evolve in the same manner during aluminizing and result in a three-layer structure with an outer PtAl2 + NiAl two-phase layer, an intermediate NiAl layer, and the inner interdiffusion layer. The stability of this three-layer coating structure over long periods of aluminizing, however, is dependent on the availability of Al from the pack during this period. Below a certain threshold Al availability, the two-phase outer layer transforms to a single-phase NiAl structure causing the coating to change from its three-layer structure to a two-layer one. Cyclic oxidation results indicate that, while a minimum Al content in Pt-aluminide coatings is essential for deriving the best oxidation performance, increasing the Al content beyond a certain level does not significantly enhance oxidation behavior. The effect of Al content on aspects, such as coating degradation and nature of coating-surface damage during cyclic oxidation, is also discussed.
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| 5. |
- Das, D. K., et al.
(författare)
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Effect of prealuminizing diffusion treatment on microstructural evolution of high-activity pt-aluminide coatings
- 2000
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Ingår i: Metallurgical and Materials Transactions. A. - 1073-5623 .- 1543-1940. ; 31:8, s. 2037-2047
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Tidskriftsartikel (refereegranskat)abstract
- The effect of prealuminizing (or prior) diffusion treatment on the evolution of Pt-aluminide coatings on the Ni-based superalloy CM-247 has been studied by using a single-step, high-activity aluminizing process. Coatings generated without any prior diffusion treatment, as well as those formed by adopting two extreme prior-diffusion schedules (at 850 °C for 0.5 hours and at 1034 °C for 5 hours), were investigated by analyzing the coating structures at various stages of aluminizing. When the dilution of the Pt layer, caused by its interdiffusion with the substrate during the prior diffusion treatment, is only marginal (as in the case of no prior diffusion and diffusion at 850 °C for 0.5 hours), the equilibrium Pt-aluminide coating structure evolves through the formation of two transient layers during the initial stages of aluminizing. In contrast, for diffusion at 1034 °C for 5 hours, which results in extensive dilution of the Pt layer, the two-phase equilibrium structure (PtAl2 in a matrix of NiAl) in the outer layer of the coating is found to develop during very early stages of aluminizing and remains unchanged, even over extended periods of aluminizing. Further, in the case of prior diffusion at 1034 °C for 5 hours, Pt is found to remain distributed to a greater extent over the entire thickness of the coating than in the cases of limited prior diffusion treatment. The present findings underline the significance of the nature of the prior-diffusion schedule on the microstructural evolution of Pt-aluminide coatings. It has also been found that a prealuminizing diffusion treatment is particularly important for Pt-aluminide coatings from the point of view of coating adhesion to the substrate.
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| 6. |
- Sanyal, S.C., Bhattacharyya, D., Das Gupta, C.
(författare)
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The folding of dimeric cytoplasmic malate dehydrogenase. Equilibrium and kinetic studies
- 2002
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Ingår i: Eur J Biochem. ; 269:15, s. 3856-66
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Tidskriftsartikel (refereegranskat)abstract
- Porcine heart cytoplasmic malate dehydrogenase (s-MDH) is a dimeric protein (2 x 35 kDa). We have studied equilibrium unfolding and refolding of s-MDH using activity assay, fluorescence, far-UV and near-UV circular dichroism (CD) spectroscopy, hydrophobic
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