14,406,106 research outputs found
Thermoelectric figure of merit of tau-type conductors of several donors
Dimensionless thermoelectric figure of merit is investigated for
two-dimensional organic conductors ,
-(EDT-S,S-DMEDT-TTF)_2(AuI_2)_{1+y}\tau (), respectively. The
values were estimated by measuring electrical resistivity, thermopower and
thermal conductivity simultaneously. The largest is 2.7 10
at 155 K for , 1.5 10
at 180 K for and 5.4
10 at 78 K for , respectively.
Substitution of the donor molecules fixing the counter anion revealed
EDT-S,S-DMEDT-TTF is the best of the three donors to obtain larger .Comment: proceedings of ISCOM 2009 (to be published in Physica B
Inferring an Indeterminate String from a Prefix Graph
An \itbf{indeterminate string} (or, more simply, just a \itbf{string}) \s{x}
= \s{x}[1..n] on an alphabet is a sequence of nonempty subsets of
. We say that \s{x}[i_1] and \s{x}[i_2] \itbf{match} (written
\s{x}[i_1] \match \s{x}[i_2]) if and only if \s{x}[i_1] \cap \s{x}[i_2] \ne
\emptyset. A \itbf{feasible array} is an array \s{y} = \s{y}[1..n] of
integers such that \s{y}[1] = n and for every , \s{y}[i] \in
0..n\- i\+ 1. A \itbf{prefix table} of a string \s{x} is an array \s{\pi} =
\s{\pi}[1..n] of integers such that, for every , \s{\pi}[i] = j
if and only if \s{x}[i..i\+ j\- 1] is the longest substring at position
of \s{x} that matches a prefix of \s{x}. It is known from \cite{CRSW13} that
every feasible array is a prefix table of some indetermintate string. A
\itbf{prefix graph} \mathcal{P} = \mathcal{P}_{\s{y}} is a labelled simple
graph whose structure is determined by a feasible array \s{y}. In this paper we
show, given a feasible array \s{y}, how to use \mathcal{P}_{\s{y}} to
construct a lexicographically least indeterminate string on a minimum alphabet
whose prefix table \s{\pi} = \s{y}.Comment: 13 pages, 1 figur
Can Y(4140) be a tetraquark ?
In this exploratory study the spectrum of tetraquarks of type is calculated within a simple quark model with chromomagnetic
interaction and effective quark masses extracted from meson and baryon spectra.
It is tempting to see if this spectrum can accommodate the resonance Y(4140),
observed by the CDF collaboration, but not yet confirmed. The results seem to
favour the J = 1 sector where the coupling to the VV channel is
nearly as small as that of X(3872), when described as a
tetraquark. This suggests that Y(4140) could possibly be the strange partner of
X(3872), in a tetraquark interpretation. However the sector J = 0
cannot entirely be excluded. This work questions the practice of extracting
effective quark masses containing spin independent contributions, from mesons
and baryons, to be used in multiquark systems as well.Comment: new additional parts, published versio
ORION S-band data acquisition for S-Y calibration
Error sources in the Operational Radio Interferometry Observing Network (ORION) are addressed. Specifically, the performance of the S-band receiver and the optimum allocation of data volume between S- and X-band observations is studied. It is found that the requirements on the S-band receiver are not very stringent. The system temperature of the ORION S-band receiver has a very small effect on baseline determination accuracy. It is unwise to pay a high cost for an S-band receiver with a low system temperature; a system temperature as high as 240 K is tolerable. Only 20 to 40 percent of data volume is to be allocated to S-band observations for minimum baseline error. The error remains low over a rather wide range of data volume ratio. Hence precise allocation of the 14 pairs of the Mark 3 very long base interferometer data channels between S- and X-band observations is not critical
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