The nano-scale structure of cytoskeletal biopolymers as well as sophisticated superstructures determine the versatile cellular shapes and specific mechanical properties. One example is keratin intermediate filaments in epithelial cells, which form thick bundles that can further organize in a crosslinked network. To study the native structure of keratin bundles in whole cells, high-resolution te...

A study is presented of a possible future measurement of the longitudinal structure function FL(x,Q ) with different proton beam energies at HERA. To appear in the proceedings of the workshop “Future Physics at HERA”, DESY, Hamburg, 1996. Future Measurement of the Longitudinal Proton Structure Function at HERA L.A.T. Bauerdick, A. Glazov, M. Klein a DESY, Notkestraße 85, D-22607 Hamburg, German...

We describe a method for characterizing focused x-ray beams using phase retrieval, with diversity achieved by transversely translating a phase-shifting or absorbing structure close to the beam focus. The required measurements can be taken with an experimental setup that is similar to that already used for fluorescent scan testing. The far-field intensity pattern is measured for each position of...

The structure optimization of main beam is a nonlinear constrained optimization problem, which is important for bridge crane to save manufacturing cost on quality assurance. The modified particle swarm optimization (MPSO) with feasibility-based rules [1], which was advanced to solve mixed-variable optimization problems, is proposed to optimize the structure of main beam in order to find the opt...

Beams with helical phasefronts described by exp(ilphi) carry an orbital angular momentum equivalent to lh per photon. Using diffractive optics this helical phase structure can be applied to every spectral component of the beam such that a spatially coherent white-light beam can carry orbital angular momentum without any chromatic distortion. This achromatic property can be hard to achieve in sp...