4,893 research outputs found
Prediction of Nontrivial Band Topology and Superconductivity in MgPb
The interplay of BCS superconductivity and nontrivial band topology is
expected to give rise to opportunities for creating topological
superconductors, achieved through pairing spin-filtered boundary modes via
superconducting proximity effects. The thus-engineered topological
superconductivity can, for example, facilitate the search for Majorana fermion
quasiparticles in condensed matter systems. Here we report a first-principles
study of MgPb and predict that it should be a superconducting topological
material. The band topology of MgPb is identical to that of the archetypal
quantum spin Hall insulator HgTe, while isostructural and isoelectronic
MgSn is topologically trivial; a trivial to topological transition is
predicted for MgSnPb for x~0.77. We propose that
MgPb-MgSn quantum wells should generate robust spin-filtered edge
currents in analogy to HgTe/CdTe quantum wells. In addition, our calculations
predict that MgPb should become superconducting upon electron doping.
Therefore, MgPb is expected to provide a practical material platform for
studying emergent phenomena arising from the interplay of superconductivity and
band topology.Comment: 5 figure
Pair-Linking for Collective Entity Disambiguation: Two Could Be Better Than All
Collective entity disambiguation aims to jointly resolve multiple mentions by
linking them to their associated entities in a knowledge base. Previous works
are primarily based on the underlying assumption that entities within the same
document are highly related. However, the extend to which these mentioned
entities are actually connected in reality is rarely studied and therefore
raises interesting research questions. For the first time, we show that the
semantic relationships between the mentioned entities are in fact less dense
than expected. This could be attributed to several reasons such as noise, data
sparsity and knowledge base incompleteness. As a remedy, we introduce MINTREE,
a new tree-based objective for the entity disambiguation problem. The key
intuition behind MINTREE is the concept of coherence relaxation which utilizes
the weight of a minimum spanning tree to measure the coherence between
entities. Based on this new objective, we design a novel entity disambiguation
algorithms which we call Pair-Linking. Instead of considering all the given
mentions, Pair-Linking iteratively selects a pair with the highest confidence
at each step for decision making. Via extensive experiments, we show that our
approach is not only more accurate but also surprisingly faster than many
state-of-the-art collective linking algorithms
PV panel modeling and identification
In this chapter, the modelling techniques of PV panels from I-V characteristics
are discussed. At the beginning, a necessary review on the various methods are presented,
where difficulties in mathematics, drawbacks in accuracy, and challenges in
implementation are highlighted. Next, a novel approach based on linear system identification
is demonstrated in detail. Other than the prevailing methods of using approximation
(analytical methods), iterative searching (classical optimization), or soft
computing (artificial intelligence), the proposed method regards the PV diode model
as the equivalent output of a dynamic system, so the diode model parameters can be
linked to the transfer function coefficients of the same dynamic system. In this way,
the problem of solving PV model parameters is equivalently converted to system identification
in control theory, which can be perfectly solved by a simple integral-based
linear least square method. Graphical meanings of the proposed method are illustrated
to help readers understand the underlying principles. As compared to other methods,
the proposed one has the following benefits: 1) unique solution; 2) no iterative or
global searching; 3) easy to implement (linear least square); 4) accuracy; 5) extendable
to multi-diode models. The effectiveness of the proposed method has been verified by
indoor and outdoor PV module testing results. In addition, possible applications of
the proposed method are discussed like online PV monitoring and diagnostics, noncontact
measurement of POA irradiance and cell temperature, fast model identification
for satellite PV panels, and etc
A Model for Mapping Interactivity in Learning Experiences
This research is situated at the intersection of technology, education, and design. A design methodology was applied to examine the issues relating to interactivity within these disciplines. The result of this research is a working definition of interactivity aesthetics that can be used across multiple disciplines, and a model of interactivity as a practical means of evaluating the interactivity in any given learning experience
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