1,351 research outputs found
Nonlinear thermoelectric response due to energy-dependent transport properties of a quantum dot
Quantum dots are useful model systems for studying quantum thermoelectric
behavior because of their highly energy-dependent electron transport
properties, which are tunable by electrostatic gating. As a result of this
strong energy dependence, the thermoelectric response of quantum dots is
expected to be nonlinear with respect to an applied thermal bias. However,
until now this effect has been challenging to observe because, first, it is
experimentally difficult to apply a sufficiently large thermal bias at the
nanoscale and, second, it is difficult to distinguish thermal bias effects from
purely temperature-dependent effects due to overall heating of a device. Here
we take advantage of a novel thermal biasing technique and demonstrate a
nonlinear thermoelectric response in a quantum dot which is defined in a
heterostructured semiconductor nanowire. We also show that a theoretical model
based on the Master equations fully explains the observed nonlinear
thermoelectric response given the energy-dependent transport properties of the
quantum dot.Comment: Cite as: A. Svilans, et al., Physica E (2015),
http://dx.doi.org/10.1016/j.physe.2015.10.00
Pengaruh alokasi anggaran sektor pertanian dan industri terhadap PDRB di Kabupaten Kerinci
This study aims to analyze the development of the agricultural and industrial sector budgets and analyze the effect of the farming and industrial sector budget allocations on the GRDP in the Kerinci district. The analytical method used is multiple linear regression with Ordinary Least Square (OLS). This study indicates that the development of the industrial sector budget in Kerinci Regency for the 2010 to 2020 period has fluctuated with an average growth of Rp. 36,920,377,491 per year and the average industrial sector budget in Kerinci Regency for the 2010 to 2020 period is Rp. 8,154,752,012 per year. And the results of the analysis of factors that affect GRDP in Kerinci Regency, simultaneously the agricultural and industrial sector budget variables have a significant effect on GRDP, and partially the industrial sector budget has a significant impact. The farm sector budget has no significant effect.
Keywords: GRDP, Agriculture sector budget, Industry sector budget
A quantum-dot heat engine operating close to the thermodynamic efficiency limits
Cyclical heat engines are a paradigm of classical thermodynamics, but are
impractical for miniaturization because they rely on moving parts. A more
recent concept is particle-exchange (PE) heat engines, which uses energy
filtering to control a thermally driven particle flow between two heat
reservoirs. As they do not require moving parts and can be realized in
solid-state materials, they are suitable for low-power applications and
miniaturization. It was predicted that PE engines could reach the same
thermodynamically ideal efficiency limits as those accessible to cyclical
engines, but this prediction has not been verified experimentally. Here, we
demonstrate a PE heat engine based on a quantum dot (QD) embedded into a
semiconductor nanowire. We directly measure the engine's steady-state electric
power output and combine it with the calculated electronic heat flow to
determine the electronic efficiency . We find that at the maximum power
conditions, is in agreement with the Curzon-Ahlborn efficiency and that
the overall maximum is in excess of 70 of the Carnot efficiency
while maintaining a finite power output. Our results demonstrate that
thermoelectric power conversion can, in principle, be achieved close to the
thermodynamic limits, with direct relevance for future hot-carrier
photovoltaics, on-chip coolers or energy harvesters for quantum technologies
Economic Integration
The results of international trade have generated a set of both winners and losers. On one side we have the big companies and big producers that stand out and on the other hand, there is a sector that has been affected such as groups of peasants, rural communities, cooperatives, amongst others that live in the poor southern countries. Therefore, the objective of this research article is the search and the design of mechanisms that will counteract the flaws of the current systems, and that will translate into social policies to give a solution to the more unprotected people. Fair trade is an alternative that is heading towards practices of a more social and solidary economy and through these mechanisms, that are funded in
Thermoelectric characterization of the Kondo resonance in nanowire quantum dots
We experimentally verify hitherto untested theoretical predictions about the
thermoelectric properties of Kondo correlated quantum dots (QDs). The specific
conditions required for this study are obtained by using QDs epitaxially grown
in nanowires, combined with a recently developed method for controlling and
measuring temperature differences at the nanoscale. This makes it possible to
obtain data of very high quality both below and above the Kondo temperature,
and allows a quantitative comparison with theoretical predictions.
Specifically, we verify that Kondo correlations can induce a polarity change of
the thermoelectric current, which can be reversed either by increasing the
temperature or by applying a magnetic field
The methanol emission in the A line series as a tracer of specific physical conditions in high-mass star-forming regions
We present results of the investigations of the properties of the methanol
A line series motivated by the recent serendipitous
detection of the maser emission in the A line at 349~GHz
in S255IR-SMA1 soon after the accretion burst. The study includes further
observations of several lines of this series in S255IR with the SMA, a
mini-survey of methanol lines in the 0.8 mm range toward a sample of bright
6.7~GHz methanol maser sources with the IRAM-30m telescope, and theoretical
modeling. We found that the maser component of the A line
in S255IR decayed by more than order of magnitude in comparison with that in
2016. No clear sign of maser emission is observed in other lines of this series
in the SMA observations except the A line where an
additional bright component is detected at the velocity of the maser emission
observed earlier in the A line. Our LVG model constrains
the ranges of the physical parameters that matches the observed emission
intensities. No obvious maser emission in the A lines was
detected in the mini-survey of the 6.7~GHz methanol maser sources, though one
component in NGC7538 may represent a weak maser. In general, the maser effect
in the A lines may serve as a tracer of rather hot
environments and in particular luminosity flaring events during high mass star
formation.Comment: 16 pages, 12 figure
IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.
Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity
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