487 research outputs found

    Polyaniline-silver hybrid materials for ink-jet printing

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    The synthesis of PANI/Ag hybrid materials has been carried out via a rapid chemical oxidative, in-situ polymerisation method, using silver nitrate and ammonium peroxydisulfate as oxidant precursors. These species react together to produce Ag2+, an oxidising intermediate which has greater oxidising power than either persulphate or Ag+ alone. The reaction thus proceeds at a much accelerated rate than that of pure PANI, approximately 6 times faster. Various characterisation techniques were used to characterise this new hybrid material, PANI-Ag. UV-vis absorption spectroscopy was used to follow the formation of polymer over time and monitor the rate at which the reaction progresses for both PANI and PANI-silver. It is evident from the absorption spectra that the polymer forms via the fully-oxidised pernigraniline state initially, before reducing back into the more stable emeraldine salt form. This process is significantly accelerated using both APS and AgNO3, as opposed to when using APS or AgNO3 alone. These new composites could potentially find use as functional materials for the printed electronics industry where new processable, hybrid materials as required for applications in sensing, memory, logic and photovoltaics

    Hot gas and dust in a protostellar cluster near W3(OH

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    We used the IRAM Interferometer to obtain sub-arcsecond resolution observations of the high-mass star-forming region W3(OH) and its surroundings at a frequency of 220 GHz. With the improved angular resolution, we distinguish 3 peaks in the thermal dust continuum emission originating from the hot core region about 6 arcsec (0.06 pc) east of W3(OH). The dust emission peaks are coincident with known radio continuum sources, one of which is of non-thermal nature. The latter source is also at the center of expansion of a powerful bipolar outflow observed in water maser emission. We determine the hot core mass to be 15 solar masses based on the integrated dust continuum emission. Simultaneously many molecular lines are detected allowing the analysis of the temperature structure and the distribution of complex organic molecules in the hot core. From HNCO lines, spanning a wide range of excitation, two 200 K temperature peaks are found coincident with dust continuum emission peaks suggesting embedded heating sources within them.Comment: 12 pages, 3 figure

    Contraceptive Efficacy of a Novel Intrauterine Device (IUD) in White-Tailed Deer

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    Overabundant white-tailed deer (Odocoileus virginianus) pose risks to property, health, and safety of human beings. Public concerns about lethal management can impair efforts to address these issues, particularly in urban settings. Several techniques developed for reducing reproductive output of deer have limited utility because they require repeated dosing to achieve permanent effect and face uncertain regulatory approval for use beyond experimentation. From 10 August 2006 through 30 December 2007, we evaluated the contraceptive efficacy of copper-containing intrauterine devices (IUDs) implanted trans-cervically in white-tailed deer at the E.S. George Reserve in Pinckney, Michigan. Intrauterine devices were implanted before (n = 9) and shortly after (n = 10) the breeding season. Post-breeding season IUD treatment was in conjunction with a 5 cm3 dose of 5 mg/ml prostaglandin F2α (PGF2α), delivered subcutaneously. Intrauterine devices reduced pregnancy rates when administered prior to breeding (P \u3c 0.001) and prevented pregnancy for up to 2 years (the duration of the study). Two of 8 does that received IUDs prior to the breeding season and survived to the end of the study became pregnant (due to loss of the implant) during the second year while all (n = 16) does without implants conceived. Cervical changes associated with early pregnancy made trans-cervical implantation after the breeding season challenging, and resulted in improperly placed IUDs in 2 treated does. The apparent expulsion of IUDs by pregnant does that received the combined treatment after breeding suggests IUD treatment should be limited to the pre-breeding season. Intrauterine devices show potential as a tool for small-scale deer population management via non-steroidal reproductive inhibition

    Superconducting Gatemon Qubit based on a Proximitized Two-Dimensional Electron Gas

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    The coherent tunnelling of Cooper pairs across Josephson junctions (JJs) generates a nonlinear inductance that is used extensively in quantum information processors based on superconducting circuits, from setting qubit transition frequencies and interqubit coupling strengths, to the gain of parametric amplifiers for quantum-limited readout. The inductance is either set by tailoring the metal-oxide dimensions of single JJs, or magnetically tuned by parallelizing multiple JJs in superconducting quantum interference devices (SQUIDs) with local current-biased flux lines. JJs based on superconductor-semiconductor hybrids represent a tantalizing all-electric alternative. The gatemon is a recently developed transmon variant which employs locally gated nanowire (NW) superconductor-semiconductor JJs for qubit control. Here, we go beyond proof-of-concept and demonstrate that semiconducting channels etched from a wafer-scale two-dimensional electron gas (2DEG) are a suitable platform for building a scalable gatemon-based quantum computer. We show 2DEG gatemons meet the requirements by performing voltage-controlled single qubit rotations and two-qubit swap operations. We measure qubit coherence times up to ~2 us, limited by dielectric loss in the 2DEG host substrate
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