2,308 research outputs found
Rational Strain Engineering in Delafossite Oxides for Highly Efficient Hydrogen Evolution Catalysis in Acidic Media
The rational design of hydrogen evolution reaction (HER) electrocatalysts
which are competitive with platinum is an outstanding challenge to make
power-to-gas technologies economically viable. Here, we introduce the
delafossites PdCrO, PdCoO and PtCoO as a new family of
electrocatalysts for the HER in acidic media. We show that in PdCoO the
inherently strained Pd metal sublattice acts as a pseudomorphic template for
the growth of a strained (by +2.3%) Pd rich capping layer under reductive
conditions. The surface modification continuously improves the electrocatalytic
activity by simultaneously increasing the exchange current density j from 2
to 5 mA/cm and by reducing the Tafel slope down to 38 mV/decade,
leading to overpotentials < 15 mV for 10 mA/cm, superior
to bulk platinum. The greatly improved activity is attributed to the in-situ
stabilization of a -palladium hydride phase with drastically enhanced
surface catalytic properties with respect to pure or nanostructured palladium.
These findings illustrate how operando induced electrodissolution can be used
as a top-down design concept for rational surface and property engineering
through the strain-stabilized formation of catalytically active phases
Optimized production of a cesium Bose-Einstein condensate
We report on the optimized production of a Bose-Einstein condensate of cesium
atoms using an optical trapping approach. Based on an improved trap loading and
evaporation scheme we obtain more than atoms in the condensed phase. To
test the tunability of the interaction in the condensate we study the expansion
of the condensate as a function of scattering length. We further excite strong
oscillations of the trapped condensate by rapidly varying the interaction
strength.Comment: 9 pages, 7 figures, submitted to Appl. Phys.
Aquilegia, Vol. 24 No. 5, November-December 2000: Newsletter of the Colorado Native Plant Society
https://epublications.regis.edu/aquilegia/1182/thumbnail.jp
Aquilegia, Vol. 24 No. 4, July-October 2000: Newsletter of the Colorado Native Plant Society
https://epublications.regis.edu/aquilegia/1181/thumbnail.jp
Autonomous Slat-Cove-Filler Device for Reduction of Aeroacoustic Noise Associated with Aircraft Systems
A slat cove filler is utilized to reduce airframe noise resulting from deployment of a leading edge slat of an aircraft wing. The slat cove filler is preferably made of a super elastic shape memory alloy, and the slat cove filler shifts between stowed and deployed shapes as the slat is deployed. The slat cove filler may be configured such that a separate powered actuator is not required to change the shape of the slat cove filler from its deployed shape to its stowed shape and vice-versa. The outer contour of the slat cove filler preferably follows a profile designed to maintain accelerating flow in the gap between the slat cove filler and wing leading edge to provide for noise reduction
Operando Label-free Optical Imaging of Solution-Phase Ion Transport and Electrochemistry
Ion transport is a fundamental process in many physical, chemical, and
biological phenomena, and especially in electrochemical energy conversion and
storage. Despite its immense importance, demonstrations of label-free,
spatially and temporally resolved ion imaging in the solution phase under
operando conditions are not widespread. Here we spatiotemporally map ion
concentration gradient evolution in solution and yield ion transport parameters
by refining interferometric reflection microscopy, obviating the need for
absorptive or fluorescent labels. As an example, we use an electrochemical cell
with planar electrodes to drive concentration gradients in a ferricyanide-based
aqueous redox electrolyte, and we observe the lateral spatiotemporal evolution
of ions via concentration-dependent changes to the refractive index. Analysis
of an evolving spatiotemporal ion distribution directly yields the diffusivity
of the redox-active species. The simplicity of this approach makes it amenable
to probing local ion transport behavior in a wide range of electrochemical,
bioelectronic, and electrophysiological systems.Comment: includes supporting informatio
Efficient analysis of highly complex nuclear magnetic resonance spectra of flexible solutes in ordered liquids by using molecular dynamics
The NMR spectra of n-pentane as solute in the liquid crystal 5CB are measured at several temperatures in the nematic phase. Atomistic molecular dynamics simulations of this system are carried out to predict the dipolar couplings of the orientationally ordered pentane, and the spectra predicted from these simulations are compared with the NMR experimental ones. The simulation predictions provide an excellent starting point for analysis of the experimental NMR spectra using the covariance matrix adaptation evolutionary strategy. This shows both the power of atomistic simulations for aiding spectral analysis and the success of atomistic molecular dynamics in modeling these anisotropic systems. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705271
Aquilegia, Vol. 22 No. 6, November-December 1998: Newsletter of the Colorado Native Plant Society
https://epublications.regis.edu/aquilegia/1087/thumbnail.jp
Prophylaxis in hemophilia
Hemophilia is an inherited X-linked coagulopathy defined by a deficiency or abnormality in the clotting function of factor VIII (Hemophilia A) or factor IX (Hemophilia B). Prophylaxis – the regular administration of therapeutic products to maintain hemostasis and prevent bleeding – is the mainstream of treatment. Addressing the development and scientific evidence for administrating prophylaxis is the goal of this review. Prophylaxis is the therapeutic modality of choice for people with severe hemophilia, being considered, in principle, a lifelong treatment. It should have an early onset, ideally as a primary, or at least secondary. Even lifelong tertiary prophylaxis seems to offer benefit, although further studies are still lacking. Individualized strategies should lead to an optimization of the dilemma between better joint outcomes versus involved costs
Multiple paths through the complexities of globalization: : The next three years of Competition & Change
This document is the Accepted Manuscript version of the following article: Hulya Dagdeviren, Peter Lund-Thomsen and Leo McCann, 'Multiple paths through the complexities of globalization: The next three years of Competition & Change'. The final, definitive version of this paper has been published in Competition & Change, Vol 2 (1): 3-9, advanced access publication 1 February 2017. DOI: 10.1177/1024529416680875. © The Author(s) 2016. Published by SAGE Publishing, All rights reserved.Peer reviewe
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