University of Paderborn

About: University of Paderborn is a education organization based out in Paderborn, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 6684 authors who have published 16929 publications receiving 323154 citations.

Calcium Induced Shrinking of NaPA Chains: A SANS Investigation of Single Chain Behavior

Abstract: Calcium ions were used to induce a shrinking process with sodium polyacrylate coils in aqueous 0.01 M NaCl. By means of light scattering, four solutions with promising intermediates were selected for a detailed investigation by small-angle neutron scattering. All intermediates were half as large in size as the corresponding unperturbed dimensions but still had radii of gyration that were 45% larger than the hydrodynamic radius. The resulting SANS curves showed power laws typical for objects with a sharp boundary. They were compared with various model curves. From these models, a mixture of spheres and dumbbells resulted in theoretical curves that agreed best with experiments. The sphere size of single spheres and spheres in dumbbells was roughly 10 nm. Two spheres on a dumbbell had an averaged distance larger by almost an order of magnitude. The results are considered to be compatible with pearl necklace-like transition states of shrinking polyelectrolyte chains.

REPLICA2Pro: task relocation by bitstream manipulation in virtex-II/Pro FPGAs

Abstract: One vision of dynamic hardware reconfiguration is to deliver virtually unlimited hardware resources to a set of hardware tasks implementing arbitrary functions. By using partial reconfiguration, these tasks can be allocated and de-allocated on the reconfigurable architecture while others continue to operate. However, the exact placement of each task can only be determined during runtime according to the current resource allocation. This requires relocating each task from its original position after place and route to an area of available resources. The process of relocating tasks can result in a major time overhead. In order to solve this problem we have developed the REPLICA2Pro (Relocation per online Configuration Alteration in Virtex-2/-Pro) filter, which is capable of performing task relocations by manipulating the task's bitstream during the regular allocation process without any extra time overhead. The filter architecture, our reconfigurable system approach as well as our design flow and an experimental system setup are presented in this paper.

Highly efficient frequency conversion with bandwidth compression of quantum light.

Abstract: Hybrid quantum networks rely on efficient interfacing of dissimilar quantum nodes, as elements based on parametric downconversion sources, quantum dots, colour centres or atoms are fundamentally different in their frequencies and bandwidths Although pulse manipulation has been demonstrated in very different systems, to date no interface exists that provides both an efficient bandwidth compression and a substantial frequency translation at the same time Here we demonstrate an engineered sum-frequency-conversion process in lithium niobate that achieves both goals We convert pure photons at telecom wavelengths to the visible range while compressing the bandwidth by a factor of 747 under preservation of non-classical photon-number statistics We achieve internal conversion efficiencies of 615%, significantly outperforming spectral filtering for bandwidth compression Our system thus makes the connection between previously incompatible quantum systems as a step towards usable quantum networks