4,859 research outputs found
Keeping you in the loop: enabling web-based things management in the internet of things
Internet of Things (IoT) is an emerging paradigm where physical objects are connected and communicated over the Web. Its capability in assimilating the virtual world and the physical one offers many exciting opportunities. However, how to realize a smooth, seamless integration of the two worlds remains an interesting and challenging topic. In this paper, we showcase an IoT prototype system that enables seamless integration of the virtual and the physical worlds and efficient management of things of interest (TOIs), where services and resources offered by things can be easily monitored, visualized, and aggregated for value-added services by users. This paper presents the motivation, system design, implementation, and demonstration scenario of the system.Lina Yao, Quan Z. Sheng, Anne H.H. Ngu and Byron Ga
Progress and perspective of interface design in garnet electrolyte-based all-solid-state batteries
Inorganic solid-state electrolytes (SSEs) are nonflammable alternatives to the commercial liquid-phase electrolytes. This enables the use of lithium (Li) metal as an anode, providing high-energy density and improved stability by avoiding unwanted liquid-phase chemical reactions. Among the different types of SSEs, the garnet-type electrolytes witness a rapid development and are considered as one of the top candidates to pair with Li metal due to their high ionic conductivity, thermal, and electrochemical stability. However, the large resistances at the interface between garnet-type electrolytes and cathode/anode are the major bottlenecks for delivering desirable electrochemical performances of all-solid-state batteries (SSBs). The electrolyte/anode interface also suffers from metallic dendrite formation, leading to rapid performance degradation. This is a fundamental material challenge due to the poor contact and wettability between garnet-type electrolytes with electrode materials. Here, we summarize and analyze the recent contributions in mitigating such materials challenges at the interface. Strategies used to address these challenges are divided into different categories with regard to their working principles. On one hand, progress has been made in the anode/garnet interface, such as the successful application of Li-alloy anode and different artificial interlayers, significantly improving interfacial performance. On the other hand, the desired cathode/garnet interface is still hard to reach due to the complex chemical and physical structure at the cathode. The common methods used are nanostructured cathode host and sintering additives for increasing the contact area. On the basis of this information, we present our views on the remaining challenges and future research of electrode/garnet interface. This review not only motivates the need for further understanding of the fundamentals, stability, and modifications of the garnet/electrode interfaces but also provides guidelines for the future design of the interface for SSB
Charm-Quark Production in Deep-Inelastic Neutrino Scattering at Next-to-Next-to-Leading Order in QCD
We present a fully differential next-to-next-to-leading order calculation of charm-quark production in charged-current deep-inelastic scattering, with full charm-quark mass dependence. The next-to-next-to-leading order corrections in perturbative quantum chromodynamics are found to be comparable in size to the next-to-leading order corrections in certain kinematic regions. We compare our predictions with data on dimuon production in (anti)neutrino scattering from a heavy nucleus. Our results can be used to improve the extraction of the parton distribution function of a strange quark in the nucleon.National Natural Science Foundation (China) (Grant No. 11375013)National Natural Science Foundation (China) (Grant No. 11135003)United States. Dept. of Energy (Contract No. DE-AC02-06CH11357)United States. Dept. of Energy. Office of Nuclear Physics (U.S. DOE Contract No. DE-SC0011090
Efficient electronic entanglement concentration assisted with single mobile electron
We present an efficient entanglement concentration protocol (ECP) for mobile
electrons with charge detection. This protocol is quite different from other
ECPs for one can obtain a maximally entangled pair from a pair of
less-entangled state and a single mobile electron with a certain probability.
With the help of charge detection, it can be repeated to reach a higher success
probability. It also does not need to know the coefficient of the original
less-entangled states. All these advantages may make this protocol useful in
current distributed quantum information processing.Comment: 6pages, 3figure
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Centralized moving-horizon estimation for a class of nonlinear dynamical complex networks under event-triggered transmission scheme
Data availability statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.This article is concerned with the problem of event-triggered centralized moving-horizon state estimation for a class of nonlinear dynamical complex networks. An event-triggered scheme is employed to reduce unnecessary data transmissions between sensors and estimators, where the signal is transmitted only when certain condition is violated. By treating sector-bounded nonlinearities as certain sector-bounded uncertainties, the addressed centralized moving-horizon estimation problem is transformed into a regularized robust least-squares problem that can be effectively solved via existing convex optimization algorithms. Moreover, a sufficient condition is derived to guarantee the exponentially ultimate boundedness of the estimation error, and an upper bound of the estimation error is also presented. Finally, a numerical example is provided to demonstrate the feasibility and efficiency of the proposed estimator design method.National Natural Science Foundation of China. Grant Numbers: 61873148, 61933007, 62033008, 62073339, 62173343;
Natural Science Foundation of Shandong Province of China. Grant Number: ZR2020YQ49;
AHPU Youth Top-notch Talent Support Program of China. Grant Number: 2018BJRC009;
Natural Science Foundation of Anhui Province of China. Grant Number: 2108085MA07;
China Postdoctoral Science Foundation. Grant Number: 2018T110702;
Postdoctoral Special Innovation Foundation of Shandong Province of China. Grant Number: 201701015;
Royal Society of the UK;
Alexander von Humboldt Foundation of Germany
Electrical detection of hyperbolic phonon-polaritons in heterostructures of graphene and boron nitride
Light properties in the mid-infrared can be controlled at a deep
subwavelength scale using hyperbolic phonons-polaritons (HPPs) of hexagonal
boron nitride (h-BN). While propagating as waveguided modes HPPs can
concentrate the electric field in a chosen nano-volume. Such a behavior is at
the heart of many applications including subdiffraction imaging and sensing.
Here, we employ HPPs in heterostructures of h-BN and graphene as new
nano-optoelectronic platform by uniting the benefits of efficient hot-carrier
photoconversion in graphene and the hyperbolic nature of h-BN. We demonstrate
electrical detection of HPPs by guiding them towards a graphene pn-junction. We
shine a laser beam onto a gap in metal gates underneath the heterostructure,
where the light is converted into HPPs. The HPPs then propagate as confined
rays heating up the graphene leading to a strong photocurrent. This concept is
exploited to boost the external responsivity of mid-infrared photodetectors,
overcoming the limitation of graphene pn-junction detectors due to their small
active area and weak absorption. Moreover this type of detector exhibits
tunable frequency selectivity due to the HPPs, which combined with its high
responsivity paves the way for efficient high-resolution mid-infrared imaging
Entanglement of single-photons and chiral phonons in atomically thin WSe
Quantum entanglement is a fundamental phenomenon which, on the one hand,
reveals deep connections between quantum mechanics, gravity and the space-time;
on the other hand, has practical applications as a key resource in quantum
information processing. While it is routinely achieved in photon-atom
ensembles, entanglement involving the solid-state or macroscopic objects
remains challenging albeit promising for both fundamental physics and
technological applications. Here, we report entanglement between collective,
chiral vibrations in two-dimensional (2D) WSe host --- chiral phonons (CPs)
--- and single-photons emitted from quantum dots (QDs) present in it. CPs which
carry angular momentum were recently observed in WSe and are a
distinguishing feature of the underlying honeycomb lattice. The entanglement
results from a "which-way" scattering process, involving an optical excitation
in a QD and doubly-degenerate CPs, which takes place via two indistinguishable
paths. Our unveiling of entanglement involving a macroscopic, collective
excitation together with strong interaction between CPs and QDs in 2D materials
opens up ways for phonon-driven entanglement of QDs and engineering chiral or
non-reciprocal interactions at the single-photon level
A Unified Approach to the Classical Statistical Analysis of Small Signals
We give a classical confidence belt construction which unifies the treatment
of upper confidence limits for null results and two-sided confidence intervals
for non-null results. The unified treatment solves a problem (apparently not
previously recognized) that the choice of upper limit or two-sided intervals
leads to intervals which are not confidence intervals if the choice is based on
the data. We apply the construction to two related problems which have recently
been a battle-ground between classical and Bayesian statistics: Poisson
processes with background, and Gaussian errors with a bounded physical region.
In contrast with the usual classical construction for upper limits, our
construction avoids unphysical confidence intervals. In contrast with some
popular Bayesian intervals, our intervals eliminate conservatism (frequentist
coverage greater than the stated confidence) in the Gaussian case and reduce it
to a level dictated by discreteness in the Poisson case. We generalize the
method in order to apply it to analysis of experiments searching for neutrino
oscillations. We show that this technique both gives correct coverage and is
powerful, while other classical techniques that have been used by neutrino
oscillation search experiments fail one or both of these criteria.Comment: 40 pages, 15 figures. Changes 15-Dec-99 to agree more closely with
published version. A few small changes, plus the two substantive changes we
made in proof back in 1998: 1) The definition of "sensitivity" in Sec. V(C).
It was inconsistent with our actual definition in Sec. VI. 2) "Note added in
proof" at end of the Conclusio
Measurement of \psip Radiative Decays
Using 14 million psi(2S) events accumulated at the BESII detector, we report
first measurements of branching fractions or upper limits for psi(2S) decays
into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^-
pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\bar K^{*0}, gamma pi^+pi^-
p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with
the invariant mass of hadrons below 2.9GeV/c^2. We also report branching
fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega
f_2(1270), b_1^\pm pi^\mp, and pi^0 2(pi^+pi^-) K^+K^-.Comment: 5 pages, 4 figure
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