No abstract

Three dimensional models of crystalline zones and amorphous branching zones of starch granules are reviewed. In crystallites of both A and B starch, double helices are found in pairs, and all chains are packed in parallel arrays. The pairing of double helices is identical in both polymorphs and corresponds to the interaction between double helices that has the lowest energy. The differences between A and B starch arise from water content and the manner in which these pairs are packed in the respective crystals. A transition from B starch to the A form can be accomplished by rearrangement of the pairs of double helices. The 1–6 linked amylopectin branch points occur in amorphous regions, but actually promote the formation of ordered double helices.

Eu 8 Ga 16 Ge 30 is the only clathrate known so far where the guest positions are fully occupied by a rare-earth element. Our investigations show that, in addition to the previously synthesized Eu 8 Ga 16 Ge 30 modification with clathrate-I structure, there exists a second modification with clathrate-VIII structure. Polycrystalline samples of both phases behave as local-moment ferromagnets with relatively low Curie temperatures ͑10.5 and 36 K͒. The charge-carrier concentrations are rather small ͑3.8 and 12.5ϫ10 20 cm Ϫ3 at 2 K͒ and, together with the low Curie temperatures, point to a semimetallic behavior. Both the specific heat and the thermal conductivity are consistent with the concept of guest atoms ''rattling'' in oversized host cages, leading to low thermal conductivities ͑''phonon glasses''͒. However, the electron mobilities are quite low, which, if intrinsic, would question the properties of an ''electron crystal'', commonly presumed in ''filled-cage'' materials. The dimensionless thermoelectric figure of merit reaches values of 0.01 at 100 K.

No abstract

The algorithms have been implemented in the general-purpose motion planning software Move3D, developed at LAAS-CNRS. We are currently working on an optimized stand-alone library that will be available to the scientific community.