The response function F is expressed in terms of tbc Green function of the unperturbed system and attention is then focussed on two taxes: (i) A perfect periodic metal crystal, pert&d by V. (ii) A metal lattice with a surface in which V is embedded. A full discusxion is given of tbc inRucnce.of Fermi sutface topology on the anisotropy of Ap in the asymptotic n&m far from the defect. Provided V(...

The magnetic anisotropy phase diagrams of Pr2Co17-,Fen and Pr2Co17-,Fez-,Ty (T=Mn, Zr, Ti, Hf) compounds have been determined. Two spin reorientation temperatures, TSr1 and Tsr2, have been observed. Near the Ts,l or Ts,2 boundary the anisotropy is conical; between the two spin reorientation temperatures they exhibit uniaxial anisotropy and beyond these limits they are planar. Introduction --0-y...

We present a new method for visualizing 3D volumetric diffusion tensor MR images. We distinguish between linear anisotropy and planar anisotropy and represent values in the two regimes using streamtubes and streamsurfaces, respectively. Streamtubes represent structures with primarily linear diffusion, typically fiber tracts; streamtube direction correlates with tract orientation. The cross-sect...

This work presents a method that permits the characterization, quantification, and 3D visualization of white matter structural information contained within diffusion tensor MR imaging (DT-MRI) data. In this method, regions within the brain are defined as possessing linear, planar, or spherical diffusion. Visualization of this diffusion metric data is realized by generating streamtube and stream...

For a model with isotropic nearest neighbor exchange combined with easy-plane exchange or single-ion anisotropies, the static effects of a magnetic vacancy site on a nearby magnetic vortex are analyzed on square, hexagonal and triangular lattices. Numerical energy minimization and linear stability analysis using the vortex instability mode are employed. When the vortex is centered on a vacancy,...

Active Fiber Composites (AFC) manufactured at EMPA with commercially available piezoelectric ceramic fibers have been investigated for their potential use as Acoustic Emission (AE) sensors. AFC elements have been evaluated with methods derived from AE sensor characterization as well as additional measurements. Some commercial AE sensor types have been evaluated with the same methods for compari...

We present here the crucial effects of material anisotropy on optical field induced pattern formation in the one-feedback-mirror arrangement which utilizes the nematic liquid crystal film as the nonlinear medium. By using the quasi-static electric-field-biased planar-aligned homogeneous nematic liquid crystal (NLC) films, we observe both the hexagon and the roll patterns which can be switched o...

in an electrically anisotropic media, current density  is not aligned with the electric field  and varies with the e-field direction. this can be considered as the spatial aliasing effects aroused by the subsurface structures whose individual dimensions are smaller than the inductive length scale of diffusively propagating em fields. the role of these structures is particularly significant in t...