We investigate the ratchet dynamics of nonlinear Klein-Gordon kinks in a periodic, asymmetric lattice of pointlike inhomogeneities. We explain the underlying rectification mechanism within a collective coordinate framework, which shows that such a system behaves as a rocking ratchet for point particles. Careful attention is given to the kink width dynamics and its role in the transport. We also...

The use of sagittally bent asymmetric Laue crystals in horizontally focusing monochromators for high-energy synchrotron X-rays necessitates simulation of the X-ray reflectivity by such crystals. Based on the theory of the lattice distortion in the diffraction plane of sagittally bent Laue crystals, a lamellar model was developed to predict their rocking curves. The model was experimentally veri...

Grazing incidence specular and diffuse X-ray scattering measurements have been used to study variations in polishing of InP single crystal wafers. Excellent agreement between experimental and simulated data is achieved when graded surface layers typically 3081 in thickness, and of higher density than the bulk material, are included. Figuring was found on all samples examined and the width of th...

Residual drifts after severe earthquakes interrupt serviceability of buildings. Retrofitting of such buildings is in many cases very difficult and consumes lots of time and money. Recently, there are some attempts to develop the seismic design procedures to not only satisfy life safety criteria but also lead to more economical buildings. One of these modern methods of improving seismic performa...

In this report the transient rocking response of electrical equipment subjected to trigonometric pulses and near-source ground motions is investigated in detail. First the rocking response of a rigid block subjected to a half-sine pulse motion is reviewed. It is shown that the solution presented by Housner (1963) for the minimum acceleration amplitude of a half-sine pulse that is needed to over...

T he afternoon had been very long, longer than most, because we didn't seem to be getting anywhere. Even while his grandmother was dying in the hospital, Johnny refused to accept it. Now that she was gone, his denial grew stronger. The harder I tried to console him, the more he resisted. I wanted one thing—to give Johnny hope. I tried to explain to Johnny how death happens. But this eight-year-...