半序空间中一类算子方程的可解性

本文利用半序方法,在完备度量空间和Banach空间中分别研究了算子方程 Lx=Nx的可解性,证明了其解的存在性,并将所获结果应用于微分-积分方程的两 点边值问题.     

Invariant nearly-Kähler structures

This paper considers invariant almost Hermitian structures on a flag manifold G / P = U / K where G is a complex semi-simple Lie group, P is a parabolic subgroup of G, U is a compact real form of G and K = U ∩ P is the centralizer of a torus. The main result shows that there are nearly-Kähler structures in G / P which are not Kähler if and only if G / P has height two. This proves for the flag manifolds a conjecture by Wolf and Gray.     

Mass loss by gravitational radiation in Synge's theory

Using Synge's definition of mass for material systems, the variation of mass due to the radiation of gravitational waves is derived to any order of approximation with respect to the parameter associated with the weakness of the gravitational field generated. When certain additional boundary conditions are imposed, the result is analogous to the quadrupole formula and reduces to it in the first approximation.     

Filter design of composite trade-off filter with support regions to obtain invariant pattern recognition with defocused images

The discrimination capacity (DC) measures the ability of the filter in a pattern recognition problem to discriminate the target against other objects in the input scene. If the input scene is degraded by a defect of focus, then the DC is degraded and the pattern recognition process is worse. In this paper, we present a methodology based in the selection of ring frequency bands and in the design of the trade-off filters taking into account these frequencies to obtain several information channels. The information of all the channels is fused by means of the addition of all the channels and the geometric mean of them. Also individual channel analysis is shown. The influence on the DC and SNR of the added white noise in the input image is presented.     

On the measurement of stress in solid propellant

The problems related to the direct measurement of stresses in solid propellant are identified and reviewed. The piezoresistance phenomenon is discussed and it is shown how this phenomenon can be utilized to measure stresses in elastomers and solid propellant. One version of a piezoresistive stress transducer is used to measure radial stresses in an uncontained thick-walled elastic cylinder which is internally pressurized. A smaller similar version of the piezoresistive stress transducer is employed in a rosette configuration to measure the stress state at five critical locations in a quarter-scale Surveyor solid-propellant motor three times during a four-year storage period. The instrumentation and calibration of these piezoresistive stress transducers are briefly described.     

Post-Newtonian equations for the metric perturbation generated by a rotating elastic earth

By using Synge's approximation method to describe the unperturbed problem, we obtain the equations for the gravitational field perturbation and the Lagrangian displacement that occur when an isolated and initially self-gravitating spherical and static elastic earth gets into steady rotation. These equations are explicitly derived in an order of approximation for the initial problem where both rotation and elastic structure manifest themselves in the perturbed state.     

A novel hybrid inorganic-metalorganic compound based on a polymeric polyoxometalate and a copper complex: synthesis, crystal structure and topological studies

Reaction of monosubstituted Keggin polyoxometalates (POMs) and [Cu(ac)(pmdien)]+ generated in situ led to the formation of the hybrid metal organic-inorganic compound K5[Cu(ac)(pmdien)][SiW11CuO39].12H2O; its crystal structure and magnetic properties have also been determined. The packing of this compound can be viewed as a stacking of hydrogen-bonded chiral double chains, with the cationic complexes located between the two-dimensional arrangement of POM double chains. DFT calculations performed on [Cu(ac)(pmdien)]+ suggest that the distortion presented in this cationic copper complex is due to electronic effects. An AIM stability study of the cationic copper complex, in order to determine the relationship between the bond angle Cu-O-C and the denticity of the acetate ligand, has been carried out. Topological analyses over the polyhedral distortion, both of the monosubstituted polyanion and copper complexes, have been performed by means of continuous shape measures (CSM).     

Deformable Asymmetric Tops under Similarity Transformations

In this paper the configurations of relative equilibrium are determined for a deformable heavy top with a fixed point constrained to deform only by similarity transformations. We analyze the nonlinear orbital stability using the reduced energy–momentum method for configurations such that the center of the mass vector is parallel to the axis of gravity and coincides with an eigenvector of the Euler tensor. In addition, we study these conditions of stability for a specific deformable top given by a hyperelastic material of the Saint Venant–Kirchhoff type, and describe how these conditions are particularized in the special case of almost rigid tops.     

Two-photon cavity solitons in active optical media

We show that broad-area cascade lasers with no absorbing intracavity elements support the spontaneous formation of two-dimensional bright localized structures in a dark background. These cavity solitons consist of islands of two-photon emission embedded in a background of single-photon emission. We discuss the mechanisms through which these structures are formed and interact, along with their properties and stability.