18,463 research outputs found
Coal feed component testing for CDIF
Investigations conducted during the conceptual design of the Montana MHD Component Development and Integration Facility (CDIF) identified commercially available processing and feeding equipment potentially suitable for use in a reference design. Tests on sub-scale units of this equipment indicated that they would perform as intended
Singular Schrodinger operators in one dimension
We consider a class of singular Schr\"odinger operators that act in
, each of which is constructed from a positive function
on . Our analysis is direct and elementary. In particular it does
not mention the potential directly or make any assumptions about the magnitudes
of the first derivatives or the existence of second derivatives of . For
a large class of that have discrete spectrum, we prove that the eigenvalue
asymptotics of does not depend on rapid oscillations of or of the
potential. Similar comments apply to our treatment of the existence and
completeness of the wave operators.Comment: 23 page
Thermal blooming compensation using coherent optical adaptive techniques (COAT)
Real-time compensation for thermally induced beam distortion has been demonstrated using a phase-adaptive aperture subdivided into 18 elements coupled with an 18-channel multidither servo system. The results were obtained using an argon ion laser and a nonlinear liquid cell placed in the near field of the transmitted beam. The system increased the peak beam irradiance by more than a factor of 4 at the highest power used and reduced the beamwidth by a factor of 5.4 from the uncorrected bloomed case. A comparison with predictions from existing theory is given
All electrical manipulation of magnetization dynamics in a ferromagnet by antiferromagnets with anisotropic spin Hall effects
We investigate spin-orbit torques of metallic CuAu-I-type antiferromagnets
using spin-torque ferromagnetic resonance tuned by a dc-bias current. The
observed spin torques predominantly arise from diffusive transport of spin
current generated by the spin Hall effect. We find a growth-orientation
dependence of the spin torques by studying epitaxial samples, which may be
correlated to the anisotropy of the spin Hall effect. The observed anisotropy
is consistent with first-principles calculations on the intrinsic spin Hall
effect. Our work demonstrates large tunable spin-orbit effects in
magnetically-ordered materials.Comment: 7 pages, 6 figures, to appear in Phys. Rev. B (2015
Key dating features for timber-framed dwellings in Surrey
This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Vernacular Architecture Group 2013. MORE OpenChoice articles are open access and distributed under the terms of the Creative Commons Attribution License 3.0.The main component of the Surrey Dendrochronology Project is the accurate dating of 177 ‘dwellings’, nearly all by tree-ring analysis. The dates are used to establish date ranges for 52 ‘key features’, which cover many aspects of timber-framing from building type to details of carpentry. It is shown that changes of method and fashion were in many cases surprisingly rapid, almost abrupt in historical terms. Previous dating criteria for timber-framed dwellings in the county have been refined and new criteria introduced. Clusters of change from the 1440s and the 1540s are shown and some possible historical links suggested.The Heritage Lottery Fund, the Domestic Buildings Research Group (Surrey), the Surrey Archaeological Society and the historical societies of Charlwood, Farnham and Nutfield
Pressure Induced Changes in the Antiferromagnetic Superconductor YbPd2Sn
Low temperature ac magnetic susceptibility measurements of the coexistent
antiferromagnetic superconductor YbPd2Sn have been made in hydrostatic
pressures < 74 kbar in moissanite anvil cells. The superconducting transition
temperature is forced to T(SC) = 0 K at a pressure of 58 kbar. The initial
suppression of the superconducting transition temperature is corroborated by
lower hydrostatic pressure (p < 16 kbar) four point resisitivity measurements,
made in a piston cylinder pressure cell. At ambient pressure, in a modest
magnetic field of ~ 500 G, this compound displays reentrant superconducting
behaviour. This reentrant superconductivity is suppressed to lower temperature
and lower magnetic field as pressure is increased. The antiferromagnetic
ordering temperature, which was measured at T(N) = 0.12 K at ambient pressure
is enhanced, to reach T(N) = 0.58 K at p = 74 kbar. The reasons for the
coexistence of superconductivity and antiferromagnetism is discussed in the
light of these and previous findings. Also considered is why superconductivity
on the border of long range magnetic order is so much rarer in Yb compounds
than in Ce compounds. The presence of a new transition visible by ac magnetic
susceptibility under pressure and in magnetic fields greater than 1.5 kG is
suggested.Comment: 5 pages, 6 figure
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