Surface Induced Order in Liquid Metals and Binary Alloys

Measurements of the surface x-ray scattering from several pure liquid metals (Hg, Ga, and In) and from three alloys (Ga-Bi, Bi-In, and K-Na) with different heteroatomic chemical interactions in the bulk phase are reviewed. Surface-induced layering is found for each elemental liquid metal. The surface structure of the K-Na alloy resembles that of an elemental liquid metal. Bi-In displays pair formation at the surface. Surface segregation and a wetting film are found for Ga-Bi.Comment: 10 pages, 3 fig, published in Journal of Physics: Condensed Matte

Collateral Damage: The impact of Australian asylum seeker policy on Christmas Islanders (2001-2011)

Since the Tampa incident in 2001, Christmas Island has been a central site where Australia’s border protection and asylum seeker policies are visible This article takes four key events over a ten year period to track the impact on Christmas Islanders and on the Islanders’ changing attitudes towards asylum seekers, detention and federal government policies. The views of Christmas Islanders are not often heard in public discourse about detention on the island. This article seeks to provide a platform for a snapshot of views and to call for a greater role for Islanders in decisions that profoundly affect their lives

Microscopic Surface Structure of Liquid Alkali Metals

We report an x-ray scattering study of the microscopic structure of the surface of a liquid alkali metal. The bulk liquid structure factor of the eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the properties of an elemental liquid alkali metal. Analysis of off-specular diffuse scattering and specular x-ray reflectivity shows that the surface roughness of the K-Na alloy follows simple capillary wave behavior with a surface structure factor indicative of surface induced layering. Comparison of thelow-angle tail of the K67Na33 surface structure factor with the one measured for liquid Ga and In previously suggests that layering is less pronounced in alkali metals. Controlled exposure of the liquid to H2 and O2 gas does not affect the surface structure, indicating that oxide and hydride are not stable at the liquid surface under these experimental conditions.Comment: 12 pages, 3 figures, published in Phys. Rev.

Competition between Surface Layering and Surface Phase Formation in Dilute Liquid Hg−Au Alloys

We present temperature-dependent X-ray reflectivity measurements of liquid Hg alloyed with 0.06−0.20 atom % Au. At low Au concentrations, we find temperature-dependent surface-induced layering similar to that observed in pure Hg, except that the presence of Au reduces the layering amplitude. Upon approaching the solubility limit of Au in Hg, a new surface phase forms which is 1−2 atomic diameters thick and has a density of about half that of bulk Hg. We present a surface phase diagram, summarizing the evolution of this unexpected surface structure upon varying composition and temperature. Such surface modifications may account for the variations observed in catalytic and electrochemical reactions at liquid metal surfaces upon alloying.Engineering and Applied Science

Commercializing Biomedical Research Through Securitization Techniques

Biomedical innovation has become riskier, more expensive and more difficult to finance with traditional sources such as private and public equity. Here we propose a financial structure in which a large number of biomedical programs at various stages of development are funded by a single entity to substantially reduce the portfolio's risk. The portfolio entity can finance its activities by issuing debt, a critical advantage because a much larger pool of capital is available for investment in debt versus equity. By employing financial engineering techniques such as securitization, it can raise even greater amounts of more-patient capital. In a simulation using historical data for new molecular entities in oncology from 1990 to 2011, we find that megafunds of $5–15 billion may yield average investment returns of 8.9–11.4% for equity holders and 5–8% for 'research-backed obligation' holders, which are lower than typical venture-capital hurdle rates but attractive to pension funds, insurance companies and other large institutional investors

Wetting Behavior at the Free Surface of a Liquid Gallium–Bismuth Alloy: An X-ray Reflectivity Study Close to the Bulk Monotectic Point

We present X-ray reflectivity measurements from the free surface of a liquid gallium–bismuth alloy (Ga–Bi) in the temperature range close to the bulk monotectic temperature $T_{mono}$=222$^\circ$C. Our measurements indicate a continuous formation of a thick wetting film at the free surface of the binary system driven by the first order transition in the bulk at the monotectic point. We show that the behavior observed is that of a complete wetting at a tetra point of solid–liquid–liquid–vapor coexistence.Engineering and Applied Science