1,364 research outputs found
Ultrasonic Doppler measurement of renal artery blood flow
An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported
Ultrasonic Doppler measurement of renal artery blood flow
Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra
Breakdown Current Density of Graphene Nano Ribbons
Graphene nanoribbons (GNRs) with widths down to 16 nm have been characterized
for their current-carrying capacity. It is found that GNRs exhibit an
impressive breakdown current density, on the order of 10^8 A/cm2. The breakdown
current density is found to have a reciprocal relationship to GNR resistivity
and the data fit points to Joule heating as the likely mechanism of breakdown.
The superior current-carrying capacity of GNRs will be valuable for their
application in on-chip electrical interconnects. The thermal conductivity of
sub-20 nm graphene ribbons is found to be more than 1000 W/m-K
Resistivity of Graphene Nanoribbon Interconnects
Graphene nanoribbon interconnects are fabricated, and the extracted
resistivity is compared to that of Cu. It is found that the average resistivity
at a given line-width (18nm<W<52nm) is about 3X that of a Cu wire, whereas the
best GNR has a resistivity comparable to that of Cu. The conductivity is found
to be limited by impurity scattering as well as LER scattering; as a result,
the best reported GNR resistivity is 3X the limit imposed by substrate phonon
scattering. This study reveals that even moderate-quality graphene nanowires
have the potential to outperform Cu for use as on-chip interconnects.Comment: 10 pages, 3 figures, to be published in IEEE Electron Device Letter
Finite-temperature magnetism of FePd and CoPt alloys
The finite-temperature magnetic properties of FePd and
CoPt alloys have been investigated. It is shown that the
temperature-dependent magnetic behaviour of alloys, composed of originally
magnetic and non-magnetic elements, cannot be described properly unless the
coupling between magnetic moments at magnetic atoms (Fe,Co) mediated through
the interactions with induced magnetic moments of non-magnetic atoms (Pd,Pt) is
included. A scheme for the calculation of the Curie temperature () for
this type of systems is presented which is based on the extended Heisenberg
Hamiltonian with the appropriate exchange parameters obtained from
{\em ab-initio} electronic structure calculations. Within the present study the
KKR Green's function method has been used to calculate the parameters.
A comparison of the obtained Curie temperatures for FePd and
CoPt alloys with experimental data shows rather good agreement.Comment: 10 pages, 12 figure
Political differences in free will belief are associated with differences in moralization
In fourteen studies, we tested whether political conservatives’ stronger free will beliefs were linked to stronger and broader tendencies to moralize, and thus a greater motivation to assign blame. In Study 1 (meta-analysis of five studies, n=308,499) we show that conservatives have stronger tendencies to moralize than liberals, even for moralization measures containing zero political content (e.g., moral badness ratings of faces and personality traits). In Study 2, we show that conservatives report higher free will belief, and this is statistically mediated by the belief that people should be held morally responsible for their bad behavior (n=14,707). In Study 3, we show that political conservatism is associated with higher attributions of free will for specific events. Turning to experimental manipulations to test our hypotheses, we show that: when conservatives and liberals see an action as equally wrong there is no difference in free will attributions (Study 4); when conservatives see an action as less wrong than liberals, they attribute less free will (Study 5); and specific perceptions of wrongness account for the relation between political ideology and free will attributions (Study 6a and 6b). Finally, we show that political conservatives and liberals even differentially attribute free will for the same action depending on who performed it (Studies 7a-d). These results are consistent with our theory that political differences in free will belief are at least partly explicable by conservatives’ tendency to moralize, which strengthens motivation to justify blame with stronger belief in free will and personal accountability
Optical Scattering Lengths in Large Liquid-Scintillator Neutrino Detectors
For liquid-scintillator neutrino detectors of kiloton scale, the transparency
of the organic solvent is of central importance. The present paper reports on
laboratory measurements of the optical scattering lengths of the organic
solvents PXE, LAB, and Dodecane which are under discussion for next-generation
experiments like SNO+, Hanohano, or LENA. Results comprise the wavelength range
from 415 to 440nm. The contributions from Rayleigh and Mie scattering as well
as from absorption/re-emission processes are discussed. Based on the present
results, LAB seems to be the preferred solvent for a large-volume detector.Comment: 9 pages, 3 figures, accepted for publication by Rev. Scient. Instr
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