26 research outputs found
Two-Scale Kirchhoff Theory: Comparison of Experimental Observations With Theoretical Prediction
We introduce a non-perturbative two scale Kirchhoff theory, in the context of
light scattering by a rough surface. This is a two scale theory which considers
the roughness both in the wavelength scale (small scale) and in the scales much
larger than the wavelength of the incident light (large scale). The theory can
precisely explain the small peaks which appear at certain scattering angles.
These peaks can not be explained by one scale theories. The theory was assessed
by calculating the light scattering profiles using the Atomic Force Microscope
(AFM) images, as well as surface profilometer scans of a rough surface, and
comparing the results with experiments. The theory is in good agreement with
the experimental results.Comment: 6 pages, 8 figure
A new application of reduced Rayleigh equations to electromagnetic wave scattering by two-dimensional randomly rough surfaces
The small perturbations method has been extensively used for waves scattering
by rough surfaces. The standard method developped by Rice is difficult to apply
when we consider second and third order of scattered fields as a function of
the surface height. Calculations can be greatly simplified with the use of
reduced Rayleigh equations, because one of the unknown fields can be
eliminated. We derive a new set of four reduced equations for the scattering
amplitudes, which are applied to the cases of a rough conducting surface, and
to a slab where one of the boundary is a rough surface. As in the
one-dimensional case, numerical simulations show the appearance of enhanced
backscattering for these structures.Comment: RevTeX 4 style, 38 pages, 16 figures, added references and comments
on the satellites peak
Obtaining Adequate Surgical Margins in Breast-Conserving Therapy for Patients with Early-Stage Breast Cancer: Current Modalities and Future Directions
Inadequate surgical margins represent a high risk for adverse clinical outcome in breast-conserving therapy (BCT) for early-stage breast cancer. The majority of studies report positive resection margins in 20% to 40% of the patients who underwent BCT. This may result in an increased local recurrence (LR) rate or additional surgery and, consequently, adverse affects on cosmesis, psychological distress, and health costs. In the literature, various risk factors are reported to be associated with positive margin status after lumpectomy, which may allow the surgeon to distinguish those patients with a higher a priori risk for re-excision. However, most risk factors are related to tumor biology and patient characteristics, which cannot be modified as such. Therefore, efforts to reduce the number of positive margins should focus on optimizing the surgical procedure itself, because the surgeon lacks real-time intraoperative information on the presence of positive resection margins during breast-conserving surgery. This review presents the status of pre- and intraoperative modalities currently used in BCT. Furthermore, innovative intraoperative approaches, such as positron emission tomography, radioguided occult lesion localization, and near-infrared fluorescence optical imaging, are addressed, which have to prove their potential value in improving surgical outcome and reducing the need for re-excision in BCT
Backscattering enhancement of an electromagnetic wave scattered by two-dimensional rough layers
RevTeX 4 style, 18 pages, 7 figuresThe problem of an electromagnetic wave scattering by a slab with two rough boundaries is solved by a small-perturbation method under the Rayleigh hypothesis. In order to obtain a perturbative development, we use a systematic procedure which involves integral equations called the reduced Rayleigh equations. Then we will show for a dielectric slab deposited on a silver film that the backscattering enhancement can be produced by guided waves which interact with the two rough surfaces
A new application of reduced Rayleigh equations to electromagnetic wave scattering by two-dimensional randomly rough surfaces
RevTeX 4 style, 38 pages, 16 figures, added references and comments on the satellites peaksThe small perturbations method has been extensively used for waves scattering by rough surfaces. The standard method developped by Rice is difficult to apply when we consider second and third order of scattered fields as a function of the surface height. Calculations can be greatly simplified with the use of reduced Rayleigh equations, because one of the unknown fields can be eliminated. We derive a new set of four reduced equations for the scattering amplitudes, which are applied to the cases of a rough conducting surface, and to a slab where one of the boundary is a rough surface. As in the one-dimensional case, numerical simulations show the appearance of enhanced backscattering for these structures