269 research outputs found
Exceptional and Anisotropic Transport Properties of Photocarriers in Black Phosphorus
We show that black phosphorus has room-temperature charge mobilities on the
order of 10 cmVs, which are about one order of magnitude
larger than silicon. We also demonstrate strong anisotropic transport in black
phosphorus, where the mobilities along the armchair direction are about one
order of magnitude larger than zigzag direction. A photocarrier lifetime as
long as 100 ps is also determined. These results illustrate that black
phosphorus is a promising candidate for future electronic and optoelectronic
applications.Comment: 5 pages, 4 figure
Signatures of a Bardeen-Cooper-Schrieffer Polariton Laser
Microcavity exciton polariton systems can have a wide range of macroscopic
quantum effects that may be turned into better photonic technologies. Polariton
Bose-Einstein condensation (BEC) and photon lasing have been widely accepted in
the limits of low and high carrier densities, but identification of the
expected Bardeen-Cooper-Schrieffer (BCS) state at intermediate densities
remains elusive. While all three phases feature coherent photon emission,
essential differences exist in their matter media. Most studies to date
characterize only the photon field. Here, using a microcavity with strong- and
weak-couplings co-existing in orthogonal linear polarizations, we directly
measure the electronic gain in the matter media of a polariton laser,
demonstrating a BCS-like polariton laser above the Mott transition density.
Theoretical analysis reproduces the absorption spectra and lasing frequency
shifts, revealing an electron distribution function characteristic of a
polariton BCS state but modified by incoherent pumping and dissipation
Cross-linked CoMoO4/rGO nanosheets as oxygen reduction catalyst
Development of inexpensive and robust electrocatalysts towards oxygen reduction reaction
(ORR) is crucial for the cost-affordable manufacturing of metal-air batteries and fuel cells. Here
we show that cross-linked CoMoO4 nanosheets and reduced graphene oxide (CoMoO4/rGO) can
be integrated in a hybrid material under one-pot hydrothermal conditions, yielding a composite
material with promising catalytic activity for oxygen reduction reaction (ORR). Cyclic voltammetry
(CV) and linear sweep voltammetry (LSV) were used to investigate the efficiency of the fabricated
CoMoO4/rGO catalyst towards ORR in alkaline conditions. The CoMoO4/rGO composite revealed
the main reduction peak and onset potential centered at 0.78 and 0.89 V (vs. RHE), respectively.
This study shows that the CoMoO4/rGO composite is a highly promising catalyst for the ORR under
alkaline conditions, and potential noble metal replacement cathode in fuel cells and metal-air batteries
Retrieval-Augmented Classification with Decoupled Representation
Retrieval augmented methods have shown promising results in various
classification tasks. However, existing methods focus on retrieving extra
context to enrich the input, which is noise sensitive and non-expandable. In
this paper, following this line, we propose a -nearest-neighbor (KNN) -based
method for retrieval augmented classifications, which interpolates the
predicted label distribution with retrieved instances' label distributions.
Different from the standard KNN process, we propose a decoupling mechanism as
we find that shared representation for classification and retrieval hurts
performance and leads to training instability. We evaluate our method on a wide
range of classification datasets. Experimental results demonstrate the
effectiveness and robustness of our proposed method. We also conduct extra
experiments to analyze the contributions of different components in our
model.\footnote{\url{https://github.com/xnliang98/knn-cls-w-decoupling}}Comment: preprin
Electrically controlled dipolariton circuits
Electrically controlled photonic circuits hold promise for information
technologies with greatly improved energy efficiency and quantum information
processing capabilities. However, weak nonlinearity and electrical response of
typical photonic materials have been two critical challenges. Therefore hybrid
electronic-photonic systems, such as semiconductor exciton-polaritons, have
been intensely investigated for their potential to allow higher nonlinearity
and electrical control, with limited success so far. Here we demonstrate an
electrically-gated waveguide architecture for dipolar-polaritons that allows
enhanced and electrically-controllable polariton nonlinearities, enabling an
electrically-tuned reflecting switch and transistor of the dipolar-polaritons.
The polariton transistor displays blockade and anti-blockade by compressing a
dilute dipolar-polariton pulse. We project that a quantum blockade at the
single polariton level is feasible in such a device.Comment: 18 pages, 4 figures, 1 tabl
Diverse biological effects of glycosyltransferase genes from Tartary buckwheat
Background: Tartary buckwheat (Fagopyrum tataricum) is an edible cereal crop whose sprouts have been marketed and commercialized for their higher levels of anti-oxidants, including rutin and anthocyanin. UDP-glucose flavonoid glycosyltransferases (UFGTs) play an important role in the biosynthesis of flavonoids in plants. So far, few studies are available on UFGT genes that may play a role in tartary buckwheat flavonoids biosynthesis. Here, we report on the identification and functional characterization of seven UFGTs from tartary buckwheat that are potentially involved in flavonoid biosynthesis (and have varying effects on plant growth and development when overexpressed in Arabidopsis thaliana.)
Results: Phylogenetic analysis indicated that the potential function of the seven FtUFGT proteins, FtUFGT6, FtUFGT7, FtUFGT8, FtUFGT9, FtUFGT15, FtUFGT40, and FtUFGT41, could be divided into three Arabidopsis thaliana functional subgroups that are involved in flavonoid biosynthesis of and anthocyanin accumulation. A significant positive correlation between FtUFGT8 and FtUFGT15 expression and anthocyanin accumulation capacity was observed in the tartary buckwheat seedlings after cold stress. Overexpression in Arabidopsis thaliana showed that FtUFGT8, FtUFGT15, and FtUFGT41 significantly increased the anthocyanin content in transgenic plants. Unexpectedly, overexpression of FtUFGT6, while not leading to enhanced anthocyanin accumulation, significantly enhanced the growth yield of transgenic plants. When wild-type plants have only cotyledons, most of the transgenic plants of FtUFGT6 had grown true leaves. Moreover, the growth speed of the oxFtUFGT6 transgenic plant root was also significantly faster than that of the wild type. At later growth, FtUFGT6 transgenic plants showed larger leaves, earlier twitching times and more tillers than wild type, whereas FtUFGT15 showed opposite results.
Conclusions: Seven FtUFGTs were isolated from tartary buckwheat. FtUFGT8, FtUFGT15, and FtUFGT41 can significantly increase the accumulation of total anthocyanins in transgenic plants. Furthermore, overexpression of FtUFGT6 increased the overall yield of Arabidopsis transgenic plants at all growth stages. However, FtUFGT15 shows the opposite trend at later growth stage and delays the growth speed of plants. These results suggested that the biological function of FtUFGT genes in tartary buckwheat is diverse
Digital twin brain: a bridge between biological intelligence and artificial intelligence
In recent years, advances in neuroscience and artificial intelligence have
paved the way for unprecedented opportunities for understanding the complexity
of the brain and its emulation by computational systems. Cutting-edge
advancements in neuroscience research have revealed the intricate relationship
between brain structure and function, while the success of artificial neural
networks highlights the importance of network architecture. Now is the time to
bring them together to better unravel how intelligence emerges from the brain's
multiscale repositories. In this review, we propose the Digital Twin Brain
(DTB) as a transformative platform that bridges the gap between biological and
artificial intelligence. It consists of three core elements: the brain
structure that is fundamental to the twinning process, bottom-layer models to
generate brain functions, and its wide spectrum of applications. Crucially,
brain atlases provide a vital constraint, preserving the brain's network
organization within the DTB. Furthermore, we highlight open questions that
invite joint efforts from interdisciplinary fields and emphasize the
far-reaching implications of the DTB. The DTB can offer unprecedented insights
into the emergence of intelligence and neurological disorders, which holds
tremendous promise for advancing our understanding of both biological and
artificial intelligence, and ultimately propelling the development of
artificial general intelligence and facilitating precision mental healthcare
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