2,643 research outputs found
Stabilized lanthanum sulphur compounds
Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium, or strontium. This compound is an excellent thermoelectric material
Study of HST counterparts to Chandra X-ray sources in the Globular Cluster M71
We report on archival Hubble Space Telescope (HST) observations of the
globular cluster M71 (NGC 6838). These observations, covering the core of the
globular cluster, were performed by the Advanced Camera for Surveys (ACS) and
the Wide Field Planetary Camera 2 (WFPC2). Inside the half-mass radius (r_h =
1.65') of M71, we find 33 candidate optical counterparts to 25 out of 29
Chandra X-ray sources while outside the half-mass radius, 6 possible optical
counterparts to 4 X-ray sources are found. Based on the X-ray and optical
properties of the identifications, we find 1 certain and 7 candidate
cataclysmic variables (CVs). We also classify 2 and 12 X-ray sources as certain
and potential chromospherically active binaries (ABs), respectively. The only
star in the error circle of the known millisecond pulsar (MSP) is inconsistent
with being the optical counterpart. The number of X-ray faint sources with
L_x>4x10^{30} ergs/s (0.5-6.0 keV) found in M71 is higher than extrapolations
from other clusters on the basis of either collision frequency or mass. Since
the core density of M71 is relatively low, we suggest that those CVs and ABs
are primordial in origin.Comment: 12 pages, 6 figures. Accepted for publication in Astronomy and
Astrophysic
Stabilized Lanthanum Sulphur Compounds
Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium. or strontium. This novel compound is an excellent thermoelectric material
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Normalization may be ineffective for phonetic category learning
Sound categories often overlap in their acoustics, which can make phonetic learning difficult. Several studies argued that normalizing acoustics relative to context improves category separation (e.g. Dillon et al., 2013). However, recent work shows that normalization is ineffective for learning Japanese vowel length from spontaneous child-directed speech (Hitczenko et al., 2018). We show that this discrepancy arises from differences between spontaneous and controlled lab speech, and that normalization can increase category overlap when there are regularities in which contexts different sounds occur in - a hallmark of spontaneous speech. Therefore, normalization is unlikely to help in real, naturalistic phonetic learning situations
Superconductivity in Organic Compounds with Pseudo-Triangular Lattice
We study spin fluctuation (SF) mediated superconductivity (SC) in a
half-filled square lattice Hubbard model with the transfer matrices -t between
nearest neighbor sites and -t' between a half of next nearest neighbor sites
neighboring along only one of the directions, considering application of
this model to organic kappa-(BEDT-TTF)2X compounds. Varying the t'/t value from
0 to 1, one can interpolate between a square and an equilateral triangular
lattice, the latter giving frustration to antiferromagnetically (AF) coupled
spin systems. Within the fluctuation exchange (FLEX) approximation, we
calculate chi(q,omega), Tc and the SC order parameter for various model
parameter values and find that both AF and SC are suppressed as one approaches
the frustration geometry or |(t'/t)-1| \to 0. The SC phase, however, extends
beyond the AF phase boundary fairly close to t'/t=1 for realistic U/t values.
The order parameter is of x2-y2-type for t'/t1.Comment: 4 pages, 5 eps figures, to appear in J. Phys. Soc. Jp
Das 'EDV-Eingaben-Projekt' des Staatsrates der DDR: Stationen einer Odysee
Der Beitrag berichtet über die Probleme vom Umgang mit den überlieferten maschinenlesbaren Datenbeständen aus der DDR. Vorgestellt wird die wechselvolle Geschichte jenes Einsatzgebietes elektronischer Datenverarbeitung im Bereich des DDR-Eingabenwesens, welches unter dem Signum 'EDV-Projekt Eingaben der Bürger zur Erfassung und Auswertung des Inhalts der Eingaben der Bürger' zwischen 1979 bis 1989 aktenkundig geworden ist. Da das einschlägige überlieferte Schriftgut bislang weder systematisch erschlossen noch umfassend ausgewertet worden ist, wird an dieser Stelle ein grober Überblick über Konzeption und Aufbau des Eingaben-Projektes geboten. Die folgenden Ausführungen betrachtet der Verfasser daher als einen ersten Zwischen- bzw. Werkstattbericht über das noch laufende Projekt der Datenerschließung. (pre
Die Praxis der 'operativen Arbeitsgruppeneinsätze' der DDR-Volkskammer: Ergebnisse einer retrospektiven Befragung von Abgeordneten
Die Volkskammer der DDR war eine recht reiselustige Organisation. Die Mitglieder der Volkskammer reisten aus allen Teilen der Republik zu Plenar- und Ausschusssitzungen an und Abgeordnetengruppen besuchten darüberhinaus mehr oder weniger häufig ausgewählte Orte in der gesamten DDR. Solche Reisen von Arbeitsgruppen waren eine beliebte Form, in der die Volkskammer und ihre Ausschüsse ihrer Arbeit nachgingen. Hier wird eine unvermutete Nähe der obersten sozialistischen Körperschaft mit Problemen des Alltagslebens in der DDR deutlich, obwohl die Volkskammer doch faktisch bis zum Fall der Mauer 'den Bürgern gegenüber hochanonym' blieb. (ICEÜbers)'As matters stand the Volkskammer of the GDR was - slangy spoken - a rather keen travelling organisation. Not only that its members - except of the full-time staff - did travel from all over the Republic for their plenar and committee meetings at 'Erich's lampshop', groups of deputies visited - more or less incessantly - within the context of so-called 'operative missions' specifically chosen places all over the Republic of the GDR. This 'working group missions' formed an often applied method to fulfil the tasks within the activities of the Volkskammer or its committees. It shows a closeness to problems and to life unexpected in that superior socialistic representing corporation of the GDR, which in fact remained 'highly anonymous for the citizens' up to the day of the fall of the wall.' (author's abstract
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