SUMMARY Background gradients induced by magnetic susceptibility variations near air-filled cavities in the brain cause signal-intensity loss in gradient-echo images and shorten T2* considerably. With a correction method in which the exponential decay is restored with section-profile-dependent correction factors, parts of the signal intensity can be recovered. While uncorrected T2* values drop b...

Large gradual solar energetic particle events (LGSEPEs, ≥10pfu in the >10MeV channel as measured by GOES) are closely associated with coronal mass ejections (CMEs). The intensity-time profile of a LGSEPE reveals important information on the moving directions of a CME or an interplanetary CME (ICME). This paper analyzes the moving directions of ICMEs, using the intensity-time profiles of 3 typic...

The time evolution of the reduced single electron density matrix for eight electrons in a one-dimensional finite box potential driven by an intense laser field is calculated by numerically integrating the time-dependent Hartree-Fock equations. We study the effects of the Coulomb interaction, field intensity, and frequency on the time profile of the ionization process. Our computed saturation io...

The dispersion properties of the direct space-to-time pulse shaper are investigated for the first time to our knowledge. We demonstrate that phase-front curvature of the input spatial profile leads to a chirp in the output temporal waveform, which one can compensate for by varying the separation between the pulse-shaping lens and slit. Furthermore, the output intensity profile remains invariant...

We describe different types of ring-profile optical solitary wave and clusters of fundamental solitons propagating in isotropic nonlinear optical media. Such ringlike solitons carry a finite angular momentum and, depending on the value of the total momentum and structure, they either fragment quickly into several fundamental solitons that fly off the ring, or propagate stably for many diffracti...

This paper describes the extraction of the facial profile from a frontal view to provide a measure for automatic face recognition. The profile is derived from the intensity projection of the face image and is described using the Walsh power spectrum. Results have demonstrated its potential as a measure for face recognition whilst it remains relatively immune to head movement and to small change...

We report simultaneous control of the orbital angular momentum (OAM) and beam profile of vortex beams generated in two-mode polarization-maintaining optical fiber. Two higher-order eigenmodes of the fiber are combined to form optical vortices. Reduced coherence between the fiber modes decreases the mode purity. Varying the coherence of the fiber modes changes the average OAM while maintaining a...

Beam profile (emittance) and beam halo are characteristic properties of high-intensity and high energy beams that might limit the performance of the accelerator. Therefore a reliable measurement and determination of these parameters is most helpful for the understanding, tuning and improvement of the whole accelerator chain to achieve the best (at least the design-) performance. This talk will ...

In December 2003, the SIS-18 delivered a 350 MeV/u intense uranium beam and a record high intensity of more than 4 × 10 particles was achieved. The beam focal spot was elliptic while the beam power profile along the radial direction was Gaussian with a (FWHM)x = 0.85 mm and (FWHM)y = 1.6 mm. The experimentally measured temporal beam power profile is shown in Fig.1 which is very similar to a Gau...

Our aim in this paper is to obtain the best synthesis of a desired mutual intensity dis~but~on, by filtering in fractional Fourier domains. More specifically, we find the optimal fractional-domain filter that transforms a given (source) mutual intensity distribution into the desired one as closely as possible (in the minimum mean-square error sense). It is observed that, in some cases, closer a...