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51.
Anisur Rahaman Safia Yasmin Sahazada Aziz 《International Journal of Theoretical Physics》2010,49(10):2607-2620
Chiral Schwinger model with the Faddeevian anomaly is considered. It is found that imposing a chiral constraint this model
can be expressed in terms of chiral boson. The model when expressed in terms of chiral boson remains anomalous and the Gauss
law of which gives anomalous Poisson brackets between itself. In spite of that a systematic BRST quantization is possible.
The Wess-Zumino term corresponding to this theory appears automatically during the process of quantization. A gauge invariant
reformulation of this model is also constructed. Unlike the former one gauge invariance is done here without any extension
of phase space. This gauge invariant version maps onto the vector Schwinger model. The gauge invariant version of the chiral
Schwinger model for a=2 has a massive field with identical mass however gauge invariant version obtained here does not map on to that. 相似文献
52.
We investigate the thermodynamic properties of 5D static and spherically symmetric black holes in (i) Einstein–Maxwell–Gauss–Bonnet
theory, (ii) Einstein–Maxwell–Gauss–Bonnet theory with negative cosmological constant, and in (iii) Einstein–Yang–Mills–Gauss–Bonnet
theory. To formulate the thermodynamics of these black holes we use the Bekenstein–Hawking entropy relation and, alternatively,
a modified entropy formula which follows from the first law of thermodynamics of black holes. The results of both approaches
are not equivalent. Using the formalism of geometrothermodynamics, we introduce in the manifold of equilibrium states a Legendre
invariant metric for each black hole and for each thermodynamic approach, and show that the thermodynamic curvature diverges
at those points where the temperature vanishes and the heat capacity diverges. 相似文献
53.
Safia Anjum M. Shahid RafiqueM. Khaleeq-ur-Rahman K. SirajArslan Usman S.I. Hussain S. Naseem 《Journal of magnetism and magnetic materials》2012,324(5):711-716
In this paper we present the effect of low substrate temperature on structural, morphological, magnetic and optical properties of Ba-hexaferrite thin films. Films were deposited on single crystal Silicon (1 0 0) substrate employing the Pulsed Laser Deposition (PLD) technique. The structural, morphological, magnetic and optical properties are found to be strongly dependent on substrate temperature. The low substrate temperatures (room temperature to 200 °C) restrict the formation of larger grains. For the higher substrate temperature i.e., 400 °C, the grain size of the deposited thin film are much larger. The film grown at low substrate temperature do not show any anisotropy. As the substrate temperature is increased, the easy axis of the films alinged itself in the direction parallel to the film plane whereas the hard axis remained in the perpendicular direction. The higher substrate temperature caused the uniaxial magnetic anisotropy, which is very important in magnetic recording devices. The saturation magnetization and optical band gap energy values of 62 emu/cc and 1.75 eV, respectively, were achieved for the film of thickness 500 nm deposited at 400 °C. Higher values of coercivity, squareness and films thickness are associated with the growth of larger grains at higher substrate temperature. 相似文献
54.
55.
Complexes of the composition MC1HN (CH2CH2AsPh2)2 (M= =Rh(I), Ir(I) were used as catalysts for the homogeneous hydrogenation of cyclohexene over the temperature range 20–50 °C and 0.4 to 1 atm hydrogen partial pressure. The dependence of rate of hydrogenation on temperature, hydrogen concentration, catalyst concentration and substrate concentration is reported. The activation parameters of the reaction, H* and S* have been evaluated.
MC1HN (CH2CH2AsPh2)2 (M=Rh(I) Ir(I) 20–50°C 0,4 1 atm. , , . H* S*.相似文献
56.
This paper addresses the parallel machine scheduling problem in which the jobs have distinct due dates with earliness and tardiness costs. New lower bounds are proposed for the problem, they can be classed into two families. First, two assignment-based lower bounds for the one-machine problem are generalized for the parallel machine case. Second, a time-indexed formulation of the problem is investigated in order to derive efficient lower bounds throught column generation or Lagrangean relaxation. A simple local search algorithm is also presented in order to derive an upper bound. Computational experiments compare these bounds for both the one machine and parallel machine problems and show that the gap between upper and lower bounds is about 1.5%. 相似文献
57.
Adsorption of phosphate and nitrate anions on ammonium-functionalized MCM-48: effects of experimental conditions 总被引:1,自引:0,他引:1
In this study, ammonium-functionalized MCM-48 (Mobil Composite Material No. 48) was used as an adsorbent to remove nitrate (NO(-)(3)) and monobasic phosphate (H(2)PO(-)(4)) anions from aqueous solutions. The effects of operating conditions such as temperature, adsorbent loading, initial anion concentration, pH, and the presence of competitive ions on the adsorption performances were examined. Results showed that adsorption capacity decreased with increasing temperature. The adsorption capacity increased with adsorbent loading and initial anion concentration. The removal of nitrate was maximum at pH<8, while phosphate removal was maximized at pH 5. The adsorption was almost unaffected by the presence of competitive ions in the case of phosphate anions. However, their presence adversely affected nitrate adsorption. Desorption of both anions was rapidly achieved within 10 min using NaOH at 0.01 M. Regeneration tests showed that the adsorbent retained its capacity after 5 adsorption-desorption cycles. 相似文献