2,156 research outputs found
The influence of polydispersity and inhomogeneity on EXAFS of bimetallic catalysts
Get PDFThe effect of polydispersity and inhomogeneity of supported bimetallic catalysts on the EXAFS analysis is investigated with some simple model calculations. These show that EXAFS is very insensitive to polydispersity. Polydispersity and inhomogeneous distribution of the metals over the particles however have only limited influence on the ability to distinguish between core-shell particles and particles with random distribution of both metals
Half-life Limit of 19Mg
Full text linkA search for 19Mg was performed using projectile fragmentation of a 150
MeV/nucleon 36Ar beam. No events of 19Mg were observed. From the time-of-flight
through the fragment separator an upper limit of 22 ns for the half-life of
19Mg was established
Effect of skin dielectric properties on the read range of epidermal ultra-high frequency radio-frequency identification tags
Get PDFThis Letter presents an investigation of the effect of human tissue conductivity and permittivity on the performance of epidermal transfer tattoo ultra-high frequency radio-frequency identification (RFID) tags. The measurements were carried out on 20 individuals and the variations in the measured dielectric properties correlate well with variations in the measured tag read range on the individuals and to a lesser extent with their body mass index values. Simulation results also showed the effects of permittivity and conductivity on the designed resonance frequency of the RFID tag
An Efficient Approach to Obtaining Large Numbers of Distant Supernova Host Galaxy Redshifts
Full text linkWe use the wide-field capabilities of the 2dF fibre positioner and the
AAOmega spectrograph on the Anglo-Australian Telescope (AAT) to obtain
redshifts of galaxies that hosted supernovae during the first three years of
the Supernova Legacy Survey (SNLS). With exposure times ranging from 10 to 60
ksec per galaxy, we were able to obtain redshifts for 400 host galaxies in two
SNLS fields, thereby substantially increasing the total number of SNLS
supernovae with host galaxy redshifts. The median redshift of the galaxies in
our sample that hosted photometrically classified Type Ia supernovae (SNe Ia)
is 0.77, which is 25% higher than the median redshift of spectroscopically
confirmed SNe Ia in the three-year sample of the SNLS. Our results demonstrate
that one can use wide-field fibre-fed multi-object spectrographs on 4m
telescopes to efficiently obtain redshifts for large numbers of supernova host
galaxies over the large areas of sky that will be covered by future
high-redshift supernova surveys, such as the Dark Energy Survey.Comment: 22 pages, 4 figures, accepted for publication in PAS
Is the structure of 42Si understood?
Get PDFA more detailed test of the implementation of nuclear forces that drive shell
evolution in the pivotal nucleus \nuc{42}{Si} -- going beyond earlier
comparisons of excited-state energies -- is important. The two leading
shell-model effective interactions, SDPF-MU and SDPF-U-Si, both of which
reproduce the low-lying \nuc{42}{Si}() energy, but whose predictions for
other observables differ significantly, are interrogated by the population of
states in neutron-rich \nuc{42}{Si} with a one-proton removal reaction from
\nuc{43}{P} projectiles at 81~MeV/nucleon. The measured cross sections to the
individual \nuc{42}{Si} final states are compared to calculations that combine
eikonal reaction dynamics with these shell-model nuclear structure overlaps.
The differences in the two shell-model descriptions are examined and linked to
predicted low-lying excited states and shape coexistence. Based on the
present data, which are in better agreement with the SDPF-MU calculations, the
state observed at 2150(13)~keV in \nuc{42}{Si} is proposed to be the ()
level.Comment: accepted in Physical Review Letter
- …
