1,009 research outputs found
Very low bias stress in n-type organic single crystal transistors
Bias stress effects in n-channel organic field-effect transistors (OFETs) are
investigated using PDIF-CN2 single-crystal devices with Cytop gate dielectric,
both under vacuum and in ambient. We find that the amount of bias stress is
very small as compared to all (p-channel) OFETs reported in the literature.
Stressing the PDIF-CN2 devices by applying 80 V to the gate for up to a week
results in a decrease of the source drain current of only ~1% under vacuum and
~10% in air. This remarkable stability of the devices leads to characteristic
time constants, extracted by fitting the data with a stretched exponential -
that are \tau ~ 2\cdot10^9 s in air and \tau ~ 5\cdot10^9 s in vacuum -
approximately two orders of magnitude larger than the best values reported
previously for p-channel OFETs.Comment: Submitted to Applied Physics Letters; 14 pages, 3 figure
Herejía y represión en la Occitania del siglo XIII: Catarismo y Cruzada Albigense
En este trabajo, se abordan las principales características de la más importante de las herejías plenomedievales -el catarismo-, en un marco geográfico y cronológico concreto: la región de Occitania desde finales del siglo XII. Del mismo modo, se habrá de tener en cuenta el intenso proceso de represión y réplica, bien intelectual, o bien violenta, que se estableció desde el Papado, único representante de la doctrina oficial. Esta represión antiherética, que tardaría en culminarse más de un siglo, tuvo su máximo exponente en la denominada Cruzada Albigense, una dilatada guerra a gran escala, que acabó involucrando a los más poderosos señores de la cristiandad y que vio pervertidos y desvirtuados sus propósitos iniciales
Thermal performance evaluation of bischofite at pilot plant scale
The selection of the proper thermal energy storage (TES) material for an application is crucial. On the one
hand, these materials should have suitable thermal properties for the operational temperatures range of
the systems they are planned to work for, such as thermal stability, high latent heat and high heat capacity.
On the other hand, they should be available on the market and at low price. Besides, researchers have
to bear in mind the importance of testing TES materials not only at laboratory scale but also at higher
scale, since it has been demonstrated that some thermal characteristics are volume-dependant. In the
present study, bischofite, a by-product obtained from the non-metallic industry in the North of Chile with
desired thermal properties for mid-temperature applications (around 100 C), has been studied. A first
analysis was performed in terms of comparing the thermal properties and cost of bischofite with other
material previously studied as TES materials in order to evaluate its potential in both latent and sensible
phases. Afterwards, a second analysis was experimentally performed in terms of testing bischofite at
large-scale (204 kg) in a pilot plant facility. The experimental procedure consisted on several charging
processes within two different temperatures ranges: from 50 C to 80 C and from 80 C to 120 C in order
to study the behavior of the material in the sensible solid phase and latent phase respectively. The temperature
profiles, the power given by the HTF, the energy balance in the storage system and the accumulation
energy rate of the bischofite were analyzed. Results of both analysis showed that bischofite has
potential as TES material for mid-temperature applications.The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under Grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE). The work was partially funded by the Spanish government (Project ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). The authors would like to acknowledge the collaboration of the company SALMAG. The authors acknowledge to FONDECYT (Grant No 1120422), CONICYT/FONDAP No 15110019, and the Education Ministry of Chile Grant PMI ANT 1201 for the financial support. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Andrea Gutierrez would like to thank to the Education Ministry of Chile her doctorate scholarship ANT 1106 and CONICYT/PAI NO 7813110010
UBVRIz Light Curves of 51 Type II Supernovae
We present a compilation of UBV RIz light curves of 51 type II supernovae
discovered during the course of four different surveys during 1986 to 2003: the
Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the
Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II
Supernova Survey (CATS). The photometry is based on template-subtracted images
to eliminate any potential host galaxy light contamination, and calibrated from
foreground stars. This work presents these photometric data, studies the color
evolution using different bands, and explores the relation between the
magnitude at maximum brightness and the brightness decline parameter (s) from
maximum light through the end of the recombination phase. This parameter is
found to be shallower for redder bands and appears to have the best correlation
in the B band. In addition, it also correlates with the plateau duration, being
thus shorter (longer) for larger (smaller) s values.Comment: 110 pages, 9 Figures, 6 Tables, accepted in A
Chiapas : entre el autoritarismo y la transición democrática, desde Acteal hasta el diálogo EZLN y sociedad civil
Obra cuya intención es dar cuenta de los diversos actores sociales involucrados en el conflicto de Chiapas, a nivel político, económico y sociocultural. El texto recupera un taller de análisis de coyuntura sobre el tema, realizado en agosto de 1998.ITESO, A.C
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