February 2006 Archives

Diamond Light Source Ltd, the UK's next-generation synchrotron facility, and the Shanghai Synchrotron Radiation Facility (SSRF)/Shanghai Institute of Applied Physics, Chinese Academy of Sciences signed a Memorandum of Understanding (MoU) on collaborative research. Diamond will start operations in January 2007, and SSRF plans to do so 2 years later. This collaboration is part of the UK-China Partners in Science series of activities in China, a joint initiative backed by both the UK and the Chinese governments to increase scientific collaboration between the two countries. For more information on UK-China Partners in Science, visit http://www.uk.cn/science

The Pittsburgh Conference announced that Pittcon 2007 will be moved from New Orleans to Chicago; the dates of the event are February 25 to March 1, 2007. At the same time, the Committee confirmed its commitment to return the Conference to New Orleans in 2008 as planned. With over 20,000 attendees and 1,100 exhibitors, Pittcon is the largest annual scientific meeting of its kind. More information about Pittcon can be found at www.pittcon.org.

Corrosion detracts some 3% from global GDP. From a positive point of view, however, chemical attack of metal surfaces may result in surface nano-structures with interesting technological applications such as catalysts and sensors. Professor H. Dosch (Max Planck Institute) and his colleagues have recently clarified a self-organization process on the surface of Cu₃Au(111) single crystal alloy in a sulphuric acid solution, by means of a sophisticated X-ray diffraction technique with the aid of a brilliant synchrotron beam at ESRF, Grenoble, France. They observed many interesting phenomena. In the initial moments of corrosion, an extremely thin gold-rich layer, which had an unexpected crystalline and well-ordered structure, was formed. As the corrosion proceeded, this alloy layer was transformed into gold nano-islands of 20 to 1.5 nm. These islands eventually developed into a porous gold metal layer. For more information, see the paper, "Initial corrosion observed on the atomic scale", F. U. Renner et al., Nature, 439, 707-710 (2006).

At SPring-8, Harima Japan, Dr. M. Takahasi (Japan Atomic Energy Agency) and his coworkers have recently established a powerful surface X-ray diffraction tool for observing the growth process of semiconductor-like GaAs. The main feature of the method is the use of multi-energy X-rays, and because of this, it is possible to identify both the atomic arrangements and the type of atoms. Another significant advantage is the capability of real-time monitoring due to the employment of a brilliant undulator beam. It was demonstrated that the surface structure called c(4x4), which is observed under certain growth conditions, has dimmers that consist of gallium and arsenic atoms in the top surface layer. For more information, see the paper, "Element-Specific Surface X-Ray Diffraction Study of GaAs(001)-c(4×4)", M. Takahasi et al., Phys. Rev. Lett. 96, 055506 (2006).

The sketch for View on the Stour near Dedham, painted by Constable in 1822, has been analyzed by X-rays prior to Tate Britain's exhibition, Constable: the Great Landscapes, which opens on 1 June 2006. The sketch is the 4th of the 6 large River Stour paintings that Constable exhibited at the Royal Academy during 1819-1825. As with the other River Stour scenes, Constable made a preliminary full-scale compositional sketch in oils when planning the exhibition picture. The X-ray investigation clearly shows that the sketch originally included two boys fishing by the water's edge and a little girl close to one of the wooden beams marking the edge of a boat-building yard in the foreground. These figures were then painted out of the sketch by Constable and replaced by two young boys sitting on the edge of the river bank. In the finished exhibition painting, View on the Stour near Dedham, Constable altered the composition again and did not include the two boys from the sketch. X-ray analysis has successfully revealed a number of such alterations that are not visible on the surface of the work. For more information, contact Helen Beeckmans/Patricia O'Connor, Tate Press Office, Millbank, London SW1P 4RG, Phone: +44-20-7887-8730/32, Fax: +44-20-7887-8729, pressoffice@tate.org.uk