Capsule-free fluid delivery and beam-induced electrodeposition in a scanning electron microscope

Gold coated borosilicate nanocapillaries are used to locally deliver aqueous, electrolytic CuSO4 solution into the low vacuum chamber of an environmental scanning electron microscope (ESEM). Capillary flow of the liquid is induced by bringing a nanocapillary into contact with a substrate. A microscopic droplet is stabilized by controlling the droplet evaporation rate with the substrate temperature and the pressure of H2O vapor injected into the vacuum chamber. An electron beam is admitted to the droplet through a pressure limiting aperture. Electrochemical reduction of aqueous Cu2+ to solid, high purity, deposited Cu is achieved by biasing the nanocapillary and supplying current by the beam which acts as a virtual cathode and enables electrodeposition on both conductive and insulating substrates. Delivery of liquids into vacuum enables localized, capsule-free beam induced electrochemistry, opening new pathways for direct-write nano and micro-lithography via beam induced electrodeposition. © The Royal Society of Chemistry 2013

Deposition of highly porous nanocrystalline platinum on functionalized substrates through fluorine-induced decomposition of Pt(PF<inf>3</inf>) <inf>4</inf> adsorbates

Nanocrystalline platinum is synthesized at room temperature by co-injecting Pt(PF3)4 and XeF2 vapors onto solid supports in vacuum. The Pt nucleation time scales with chemisorbed fluorine coverage, which is controlled by pre-dosing supports with XeF2, and by optional electron or ion beam irradiation under flowing XeF2. The latter is used to increase the chemisorbed fluorine coverage and localize the Pt growth process. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Social Workers\u27 Perceptions of Family Preservation Programs

The passage of the Adoptions and Safe Families Act of 1997, with its focus on child safety and concurrent planning, has presented family preservation workers with new challenges and new opportunities. Twenty volunteers from a large comprehensive social service agency were interviewed to determine their experiences with two models of family preservation—Multisystemic Therapy (MST) and Traditional Family Preservation Service (TFPS) or practice as usual. Workers from both programs were able to articulate values consistent with family preservation as important strengths of the programs— keeping families together and empowering families for example. Information from referring agencies was described as variable and not especially useful when working with seriously troubled families, especially as it related to risk and child safety. Both groups indicated that the jargon of family preservation had permeated their agencies, and that working with other agencies was at times a challenge, though for different reasons. Finally, despite some reservations about the effectiveness of short-term treatment with families that face serious challenges, both groups of workers were generally satisfied with family preservation as an approach to practice

Spontaneous Growth of Gallium-Filled Microcapillaries on Ion-Bombarded GaN

Bottom-up growth of microscopic pillars is observed at room temperature on GaN irradiated with a Ga+ beam in a gaseous XeF2 environment. Ion bombardment produces Ga droplets which evolve into pillars, each comprised of a spherical Ga cap atop a Ga-fille

Maskless milling of diamond by a focused oxygen ion beam

Recent advances in focused ion beam technology have enabled high-resolution, maskless nanofabrication using light ions. Studies with light ions to date have, however, focused on milling of materials where sub-surface ion beam damage does not inhibit device performance. Here we report on maskless milling of single crystal diamond using a focused beam of oxygen ions. Material quality is assessed by Raman and luminescence analysis, and reveals that the damage layer generated by oxygen ions can be removed by non-intrusive post-processing methods such as localised electron beam induced chemical etching

Supporting Student Knowledge Using Formative Assessment and Universal Design for Learning Expression

This article demonstrates an approach for teachers to use outcomes from activities using the universal design for learning expression principle to evaluate student knowledge in content areas. Based on the student’s level of explanation using a variety of expression methods, teachers can determine whether students need additional support for re-teaching a concept or whether students are ready for additional practice or challenge. Various levels of technology can be used for formatively assessing student understanding, from no technology (e.g., paper and pencil) to mid- or high-technology tools found in most classrooms, including computers and tablets

Biogeochemical effects of iron availability on primary producers in a shallow marine carbonate environment

We completed a synoptic survey of iron, phosphorus, and sulfur concentrations in shallow marine carbonate sediments from south Florida. Total extracted iron concentrations typically were 50 μmol g-1 dry weight (DW) and tended to decrease away from the Florida mainland, whereas total extracted phosphorus concentrations mostly were 10 μmol g-1 DW and tended to decrease from west to east across Florida Bay. Concentrations of reduced sulfur compounds, up to 40 μmol g-1 DW, tended to covary with sediment iron concentrations, suggesting that sulfide mineral formation was iron-limited. An index of iron availability derived from sediment data was negatively correlated with chlorophyll a concentrations in surface waters, demonstrating the close coupling of sediment-water column processes. Eight months after applying a surface layer of iron oxide granules to experimental plots, sediment iron, phosphorus, and sulfur were elevated to a depth of 10 cm relative to control plots. Biomass of the seagrass Thalassia testudinum was not different between control and iron addition plots, but individual shoot growth rates were significantly higher in experimental plots after 8 months. Although the iron content of leaf tissues was significantly higher from iron addition plots, no difference in phosphorus content of T. testudinum leaves was observed. Iron addition altered plant exposure to free sulfide, documented by a significantly higher δ34S of leaf tissue from experimental plots relative to controls. Iron as a buffer to toxic sulfides may promote individual shoot growth, but phosphorus availability to plants still appears to limit production in carbonate sediments

Direct-write milling of diamond by a focused oxygen ion beam

Recent advances in focused ion beam technology have enabled high-resolution, direct-write nanofabrication using light ions. Studies with light ions to date have, however, focused on milling of materials where sub-surface ion beam damage does not inhibit device performance. Here we report on direct-write milling of single crystal diamond using a focused beam of oxygen ions. Material quality is assessed by Raman and luminescence analysis, and reveals that the damage layer generated by oxygen ions can be removed by nonintrusive post-processing methods such as localised electron beam induced chemical etching