September 2005 Archives

An international team led by Professor M. Sandström (University of Stockholm) has analyzed the sulfur and iron composition of the wooden timbers of the Mary Rose, a warship of King Henry VIII of England that was wrecked in 1545 and salvaged two decades ago. Synchrotron X-rays from the Stanford Synchrotron Radiation Laboratory (USA) and the European Synchrotron Radiation Facility (France) were employed. The experimental results indicate the surviving wood contains two tons of sulfur in different forms, uniformly distributed within the 280-ton hull. In addition, the Mary Rose contains a great deal of iron from corroded iron bolts, nails and other objects from the ship. Exposed to oxygen in air, the iron catalyzes the oxidation of sulfur into sulfuric acid. For more information, see the paper, "Sulfur accumulation in the timbers of King Henry VIII's warship Mary Rose: a pathway in the sulfur cycle of conservation concern", M. Sandström et al., Proceedings of the National Academy of Sciences of USA, 102, 14165-14170 (2005).

Control of nano-structures with molecular precision is a key problem in nano sciences and technologies. While the surface can be readily imaged by scanning probe microscopes, it is not easy to observe buried structures nondestructively. Dr. O. Sakata and his colleagues recently reported on their success in fabricating Bi nanowires on a Si(001) substrate and their encapsulation in an epitaxially grown crystalline silicon layer. To explore the buried nanowires, they employed X-ray diffraction (reciprocal-lattice space mapping) with 25.3 keV photons at grazing-incidence geometry (~0.1 deg) using an image plate as a 2D detector. The results indicate that the nanolines maintain their one-dimensional character and Bi dimerization. The experiments were carried out at beamline BL13XU, SPring-8, Harima, Japan. For more information, see the paper, "Encapsulation of atomic-scale Bi wires in epitaxial silicon without loss of structure", O. Sakata et al., Phys. Rev. B 72, 121407(R) (2005).