3,596 research outputs found
Differential thermal analysis and solution growth of intermetallic compounds
To obtain single crystals by solution growth, an exposed primary
solidification surface in the appropriate, but often unknown, equilibrium alloy
phase diagram is required. Furthermore, an appropriate crucible material is
needed, necessary to hold the molten alloy during growth, without being
attacked by it. Recently, we have used the comparison of realistic simulations
with experimental differential thermal analysis (DTA) curves to address both
these problems. We have found: 1) complex DTA curves can be interpreted to
determine an appropriate heat treatment and starting composition for solution
growth, without having to determine the underlying phase diagrams in detail. 2)
DTA can facilitate identification of appropriate crucible materials. DTA can
thus be used to make the procedure to obtain single crystals of a desired phase
by solution growth more efficient. We will use some of the systems for which we
have recently obtained single-crystalline samples using the combination of DTA
and solution growth as examples. These systems are TbAl, PrNiSi,
and YMnAl.Comment: 17 pages, 8 figure
New results on heavy hadron spectroscopy with NRQCD
We present results for the spectrum of b-bbar bound states in the quenched
approximation for three different values of the lattice spacing. Results for
spin-independent splittings are shown to have good scaling behaviour;
spin-dependent splittings are more sensitive to discretisation effects. We
discuss what needs to be done to match the experimental spectrum.Comment: 3 pages, contribution to Lattice'9
Vocabulary sophistication in first-year composition assignments
This is the author accepted manuscript. The final version is available from John Benjamins Publishing via the DOI in this record.Recently-developed tools which quickly and reliably quantify vocabulary use on a range of
measures open up new possibilities for understanding the construct of vocabulary
sophistication. To take this work forward, we need to understand how these different
measures relate to each other and to human readers' perceptions of texts. This study applied
356 quantitative measures of vocabulary use generated by an automated vocabulary analysis
tool (Kyle & Crossley, 2014) to a large corpus of assignments written for First Year
Composition courses at a university in the United States. Results suggest that the majority of
measures can be reduced to a much smaller set without substantial loss of information.
However, distinctions need to be retained between measures based on content vs. function
words and on different measures of collocational strength. Overall, correlations with grades
are reliable but weak
Spin-based removal of instrumental systematics in 21cm intensity mapping surveys
Upcoming cosmological intensity mapping surveys will open new windows on the
Universe, but they must first overcome a number of significant systematic
effects, including polarization leakage. We present a formalism that uses scan
strategy information to model the effect of different instrumental systematics
on the recovered cosmological intensity signal for `single-dish'
(autocorrelation) surveys. This modelling classifies different systematics
according to their spin symmetry, making it particularly relevant for dealing
with polarization leakage. We show how to use this formalism to calculate the
expected contamination from different systematics as a function of the scanning
strategy. Most importantly, we show how systematics can be disentangled from
the intensity signal based on their spin properties via map-making. We
illustrate this, using a set of toy models, for some simple instrumental
systematics, demonstrating the ability to significantly reduce the
contamination to the observed intensity signal. Crucially, unlike existing
foreground removal techniques, this approach works for signals that are
non-smooth in frequency, e.g. polarized foregrounds. These map-making
approaches are simple to apply and represent an orthogonal and complementary
approach to existing techniques for removing systematics from upcoming 21cm
intensity mapping surveys.Comment: 19 pages, 14 Figures, 2 Tables, published in MNRA
Magnetic and thermal properties of the S = 1/2 zig-zag spin-chain compound In2VO5
Static magnetic susceptibility \chi, ac susceptibility \chi_{ac} and specific
heat C versus temperature T measurements on polycrystalline samples of In2VO5
and \chi and C versus T measurements on the isostructural, nonmagnetic compound
In2TiO5 are reported. A Curie-Wiess fit to the \chi(T) data above 175 K for
In2VO5 indicates ferromagnetic exchange between V^{4+} (S = 1/2) moments. Below
150 K the \chi(T) data deviate from the Curie-Weiss behavior but there is no
signature of any long range magnetic order down to 1.8 K. There is a cusp at
2.8 K in the zero field cooled (ZFC) \chi(T) data measured in a magnetic field
of 100 Oe and the ZFC and field cooled (FC) data show a bifurcation below this
temperature. The frequency dependence of the \chi_{ac}(T) data indicate that
below 3 K the system is in a spin-glass state. The difference \Delta C between
the heat capacity of In2VO5 and In2TiO5 shows a broad anomaly peaked at 130 K.
The entropy upto 300 K is more than what is expected for S = 1/2 moments. The
anomaly in \Delta C and the extra entropy suggests that there may be a
structural change below 130 K in In2VO5.Comment: 6 pages, 7 figures, 1 tabl
The current panorama of European Network of Earth Observation Networks and the need for an European Network of Networks - ENEON
ENEON is the European Network of Earth Observation Networks, funded by the European Union under the H2020ConnectinGEO project mainly including non-space networks to better coordinate them, with the aim of providing better observations for resolving interdisciplinary problems, to improve the European in-situ participation in GEO and in support of the implementation and monitoring of the UN Sustainable Development Goals
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