Undercooling and solidification of germanium melts studied by differential scanning calorimeter

~~Undercooling and solidification of germanium melts studied by differential scanning calorimeter~~     

Nanoscale Science and Technology at Los Alamos National Laboratory

Research in the emerging field of nanoscale science and technology has grown steadily at Los Alamos National Laboratory since 1990. This article summarizes some of this work, examining research highlights within the seven key categories of nanoscience in which Los Alamos has ongoing projects, capabilities, and facilities: (1) Materials and chemistry, (2) Theory and modeling, (3) Bioscience, (4) Investigative tools and facilities, (5) Sensors and devices, (6) Synthesis and fabrication, and (7) Education and outreach. Future research horizons are indicated throughout while institutional strategies for advancing nanoscale science are summarized at the end.     

Morphological evolution of Ge islands on the Si(100) surface: from huts to pits

The morphological evolution on the size and shape of Ge island on the Si(100) surface by depositing and subsequent annealing processes is studied in situ by using scanning tunneling microscopy at ultrahigh vacuum environment. A slower growth rate is maintained when the islands grow to larger sizes beyond the wetting layers. While at room temperature, the epitaxial strain is relieved by the formation of three‐dimensional islands (so‐called ‘hut’ clusters). When the sample is annealed at 200 °C, the strain is relieved by forming pits, having the circular cone shape but with their apex pointing down, with Ge clusters formed at the rim of pits. Copyright © 2016 John Wiley & Sons, Ltd.     

Simultaneous Determination of Cadmium,Lead, Copper and Mercury Ions Using Organofunctionalized SBA‐15 Nanostructured Silica Modified Graphite–Polyurethane Composite Electrode

A new sensor has been developed for the simultaneous detection of cadmium, lead, copper and mercury, using differential pulse and square wave anodic stripping voltammetry (DPASV and SWASV) at a graphite–polyurethane composite electrode with SBA‐15 silica organofunctionalized with 2‐benzothiazolethiol as bulk modifier. The heavy metal ions were preconcentrated on the surface of the modified electrode at ?1.1 V vs. SCE where they complex with 2‐benzothiazolethiol and are reduced to the metals, and are then reoxidized. Optimum SWASV conditions lead to nanomolar detection limits and simultaneous determination of Cd²⁺, Pb²⁺, Cu²⁺ and Hg²⁺ in natural waters was achieved.