We consider nonlinear bound states of the nonlinear Schrödinger equation i∂zφ(z, x) = −∂2 xφ− (1 + m(Nx))|φ|p−1φ, in the presence of a nonlinear periodic microstructure m(Nx). This equation models the propagation of laser beams in a medium whose nonlinear refractive index is modulated in the transverse direction, and can also arise in the study of BoseEinstein Condensation (BEC). In the nonline...

Introduction: The purpose of the current study was to investigate the effect of X-ray spectra on the sensitivity of a polymer gel dosimeter imaged with a conventional computed tomography (CT) scanner. Material and Methods: The whole process of CT imaging of an irradiated polymer gel was simulated by MCNPX Monte Carlo (MC) code. The imaging of polyacrylamide gel was accomplished by means of a co...

When earthquakes occur, energy released by the earthquake gets induced into the structure as ground motion and this energy has to be dissipated for safety reasons. To release seismic energy, the structure should damage in such a way that on one hand, collapse of structure should not occur and on the other hand, after the earthquake, damage should be economically feasible to repair. To avoid the...

PURPOSE Although the Monte Carlo (MC) method allows accurate dose calculation its usage is limited due to long computing time. In order to gain efficiency, a new macro MC (MMC) technique for proton dose calculations in homogeneous materials has been developed. METHODS The macro MC is based on a local to global MC approach. The local simulations using Geant4 consist of mono-energetic proton pe...

We predict that left-handed metamaterials with nonlinear response can support both TEand TM-polarized self-trapped localized beams, or spatial electromagnetic solitons. Such solitons appear as singleand multi-hump beams, being either symmetric or antisymmetric, and they are modified dramatically by the hysteresis-type magnetic nonlinearity and the effective domains of negative magnetic permeabi...

We discuss the mechanisms, applications, and extraction of low-divergence laser-plasma-based electron beams that represent our past, current, and future research activities in the Center for Ultrafast Optical Science at the University of Michigan. We show experimentally that these beams have superior transverse emittance of 0.06 pi mm•mrad, along with nC charge, suitable for various application...

• Prestressing levels providing different of pre-cambering are determined. Sensitivity to imperfections in conjunction with studied. Optimal prestressing found maximize structural efficiency for ultimate behaviour. Doubly-symmetric arrangements perform better no pre-cambering. Mono-symmetric upward The behaviour and performance imperfect beam-columns crossarms externally prestressed cable stays...

The shape of two-dimensional solitary beams propagating in photorefractive media with an externally applied field is studied. The analytical results indicate that, for both focusing and defocusing nonlinearities, radially symmetric self-channeled beams do not exist. Some recent experiments are interpreted in light of the present results.

Flattened Gaussian beams are characterized by a waist profile that passes in a continuous way from a nearly flat illuminated region to darkness. The steepness of the transition region is controlled by an integer parameter N representing the order of the beam. Being expressible as a sum of N Laguerre–Gauss modes, a flattened Gaussian beam turns out to be very simple to study as far as propagatio...

The analysis of the vector wave equation was conducted. The class of self-similar solutions with inhomogeneous polarization corresponding to the resonator modes is deduced. The modes with inhomogeneous polarization can be selected by a diffraction element with polarization selectivity used as one of the resonator mirrors. Diffraction elements with high polarization selectivity about 100% are ne...