28 research outputs found

    Achieving Zero Stress in Iridium, Chromium, and Nickel Thin Films

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    We examine a method for achieving zero intrinsic stress in thin films of iridium, chromium, and nickel deposited by magnetron sputter deposition. The examination of the stress in these materials is motivated by efforts to advance the optical performance of light-weight x-ray space telescopes into the regime of sub-arc second resolution that rely on control of the film stress to values within 10-100 MPa. A characteristic feature of the intrinsic stress behavior in chromium and nickel is their sensitivity to the magnitude and sign of the intrinsic stress with argon gas pressure, including the existence of a critical pressure that results in zero film stress. This critical pressure scales linearly with the film's density. While the effect of stress reversal with argon pressure has been previously reported by Hoffman and others for nickel and chromium, we have discovered a similar behavior for iridium. Additionally, we have identified zero stress in iridium shortly after island coalescence. This feature of film growth is used for achieving a total internal stress of -2.89 MPa for a 15.8 nm thick iridium film. The surface roughness of this low-stress film was examined using scanning probe microscopy (SPM) and x-ray reflectivity (XRR) at CuK and these results presented and discussed

    GluN2A NMDA Receptor Enhancement Improves Brain Oscillations, Synchrony, and Cognitive Functions in Dravet Syndrome and Alzheimer's Disease Models.

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    NMDA receptors (NMDARs) play subunit-specific roles in synaptic function and are implicated in neuropsychiatric and neurodegenerative disorders. However, the inĀ vivo consequences and therapeutic potential of pharmacologically enhancing NMDAR function via allosteric modulation are largely unknown. We examine the inĀ vivo effects of GNE-0723, a positive allosteric modulator of GluN2A-subunit-containing NMDARs, on brain network and cognitive functions in mouse models of Dravet syndrome (DS) and Alzheimer's disease (AD). GNE-0723 use dependently potentiates synaptic NMDA receptor currents and reduces brain oscillation power with a predominant effect on low-frequency (12-20Ā Hz) oscillations. Interestingly, DS and AD mouse models display aberrant low-frequency oscillatory power that is tightly correlated with network hypersynchrony. GNE-0723 treatment reduces aberrant low-frequency oscillations and epileptiform discharges and improves cognitive functions in DS and AD mouse models. GluN2A-subunit-containing NMDAR enhancers may have therapeutic benefits in brain disorders with network hypersynchrony and cognitive impairments

    A review of residential water conservation tool performance and influences on implementation effectiveness.

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    There has been sparse coverage of advances in the application of Demand-Side Management (DSM) in the academic press in recent years. At the same time a number of important DSM studies have been reported on by non-academic institutions, and there is therefore a need for a comprehensive, up to date review of the impacts of DSM tools and the factors which influence their effectiveness. This paper aims to begin to address this apparent lack of coverage with a review of residential DSM tools using recent reports of DSM campaigns in the western (developed) world collected from a range of sources. The aims are, to understand the potential for residential DSM tools to save water in different types of household under varying conditions and, identify influences on implementation effectiveness. The current review will be of interest to, among others, water company professionals, policy makers, regulators and environmental agencies
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