970 resultados para MOMENT
Resumo:
Baryon magnetic moments of p, n, Sigma(+), Sigma(-), Xi(0), Xi(-) and the beta decay ratios (G(A)/G(V)) of n -> p, Sigma(-) -> n and Xi(0) -> Sigma(+) are calculated in a colored quark cluster model. With SU(3) breaking, the model gives a good fit to the experimental values of those baryon magnetic moments and the beta decay ratios. Our results show that the orbital motion has a significant contribution to the spin and magnetic moments of those baryons and the strange component. in nucleon is small.
Resumo:
The effects of the transition dipole moment function (TDMF) on the dynamics Of O-3 photodissociation in the Hartley band have been exploited by means of exact 3D time-dependent wavepacket method using the SW potential energy surface [J. Chem. Phys. 78 (1983) 7191]. The calculations show that the explicit inclusion of the TDMF results in slight uniform reductions for the intensities of recurrence peaks of the autocorrelation function and a slight broadening of the absorption spectrum, in comparison with the result where the TDMF is assumed to be constant. The pattern of recurrence structures of the autocorrelation function is essentially unaffected. (C) 2001 Elsevier Science B.V. All rights reserved.
Resumo:
Pure X-ray diffraction profiles have been analysed for polyamide 1010 and PA1O1O-BMI system by means of multipeak fitting resolution of X-ray diffraction. The methods of variance and fourth moment have been applied to determine the particle size and strain values for the paracrystalline materials. The results indicated that both variance and fourth moment of X-ray diffraction line profile yielded approximately the same values of the particle size and the strain. The particle sizes of (100) reflection have been found to decrease with increasing BMI content, whereas the strain values increased.
Resumo:
We have investigated the relationship between the molecular configuration and dipole moment of some fluorinated liquid crystals (LCs). The aeornetries of the molecules were preliminarily optimized at empirical AM1 and then were further optimized at B3LYP/6-31G(d) level. The dipole moment has been calculated. It is strongly influenced by the position and number of fluorine substituents in the benzene ring of the molecule. The polarizability, mean polarizabilities, and anisotropic polarizability of the phenylbicyclohexane (PBC) fluorine substituents are also given and discussed. (c) 2004 Wiley Periodicals, Inc.
Resumo:
The performance of different classification approaches is evaluated using a view-based approach for motion representation. The view-based approach uses computer vision and image processing techniques to register and process the video sequence. Two motion representations called Motion Energy Images and Motion History Image are then constructed. These representations collapse the temporal component in a way that no explicit temporal analysis or sequence matching is needed. Statistical descriptions are then computed using moment-based features and dimensionality reduction techniques. For these tests, we used 7 Hu moments, which are invariant to scale and translation. Principal Components Analysis is used to reduce the dimensionality of this representation. The system is trained using different subjects performing a set of examples of every action to be recognized. Given these samples, K-nearest neighbor, Gaussian, and Gaussian mixture classifiers are used to recognize new actions. Experiments are conducted using instances of eight human actions (i.e., eight classes) performed by seven different subjects. Comparisons in the performance among these classifiers under different conditions are analyzed and reported. Our main goals are to test this dimensionality-reduced representation of actions, and more importantly to use this representation to compare the advantages of different classification approaches in this recognition task.
Resumo:
The objective of this paper is to investigate the p-ίh moment asymptotic stability decay rates for certain finite-dimensional Itό stochastic differential equations. Motivated by some practical examples, the point of our analysis is a special consideration of general decay speeds, which contain as a special case the usual exponential or polynomial type one, to meet various situations. Sufficient conditions for stochastic differential equations (with variable delays or not) are obtained to ensure their asymptotic properties. Several examples are studied to illustrate our theory.
Resumo:
In an analysis of President Obama's Acceptance Speech, this article argues that postcolonial theory is now being re-formulated for a global, transnational sensibility.
Resumo:
Since the late 1970s the western academy has encouraged the development of postcolonial literary theory and the formulation of a postcolonial literary canon existing outside the prescriptive narratives of the ‘mother’ country and empire. Having lost faith in the binary oppositions underpinning such narratives, we turned to alternative fictions that contested the construction of the ‘other’, the world divided between the ‘West and the Rest’. The publication of Edward Said’s Orientalism in 1978 marked the beginning of the discipline now known as postcolonial studies with its new ways of understanding ‘the west’s’ relationship with ‘the east’ and, by extension, all the former colonies of empire. Despite these radical origins, however, postcolonialism’s more recent emphasis on the psychological and its affirmation of the hybrid text and self has, for many, served to obscure real economic social realities that have very little to do with the magical or wondrous textual expression of a postcolonial identity. This paper considers problems associated with defining the postcolonial and proposes that, in a literary context, we broaden its meaning to include texts traditionally outside the category of postcolonial literature. To extend the meaning of postcolonial is timely as we are now witnessing its relocation from ‘margin’ to ‘centre’ with the election of Barack Obama. This moment may be seen as a disruption of conventional understandings of what constitutes postcolonial literature, essentially as oppositional discourse that could only define itself as peripheral to, or ‘post’, metropolitan and economic concerns. [From the Author]
Resumo:
The authors have recently described a cold-formed steel portal framing system in which simple bolted moment-connections, formed through brackets, were used for the eaves and apex joints. Such connections, however, cannot be considered as rigid because of localised in-plane elongation of the bolt-holes caused by bearing against the bolt-shanks. To therefore predict the initial stiffness of such connections, it is necessary to know the initial bolt-hole elongation stiffness k(b). In this paper, a finite element-solid idealisation of a bolted lap joint in shear will be described that can be used to determine k(b); the results obtained are validated against experimental data. A beam idealisation of a cold-formed steel bolted moment-connection is then described, in which spring elements are used to idealise the rotational flexibility of the bolt-groups resulting from bolt-hole elongation: Using the value of k(b) in the beam idealisation, the deflections predicted are shown to be similar to those measured experimentally in laboratory tests conducted on the apex joint of a cold-formed steel portal frame. (C) 2003 Elsevier Ltd. All rights reserved.
Resumo:
The behaviour and design of bolted moment-connections between cold-formed steel members, formed by using brackets bolted to the webs of the section, is considered. The particular problem of the moment-capacity of such joints being lower than that of the cold-formed steel sections being connected because of web buckling, caused by the concentration of load transfer from the bolts, is addressed. In this paper, a combination of laboratory tests and finite element analyses is used to investigate this mode of failure. It is demonstrated that there is good agreement between the measured ultimate moment-capacity and that predicted by using the finite element method. A parametric study conducted using the finite element model shows that the moment-capacity of a practical size joint can be up to 20% lower than that of the cold-formed steel sections being connected. Web buckling so-caused must therefore be considered in the design of such connections. (C) 2003 Elsevier Ltd. All rights reserved.