103 research outputs found
Disorder Improves Light Absorption in Thin Film Silicon Solar Cells with Hybrid Light Trapping Structure
We present a systematic simulation study on the impact of disorder in thin film silicon solar cells with hybrid light trapping structure. For the periodical structures introducing certain randomness in some parameters, the nanophotonic light trapping effect is demonstrated to be superior to their periodic counterparts. The nanophotonic light trapping effect can be associated with the increased modes induced by the structural disorders. Our study is a systematic proof that certain disorder is conceptually an advantage for nanophotonic light trapping concepts in thin film solar cells. The result is relevant to the large field of research on nanophotonic light trapping which currently investigates and prototypes a number of new concepts including disordered periodic and quasiperiodic textures. The random effect on the shape of the pattern (position, height, and radius) investigated in this paper could be a good approach to estimate the influence of experimental inaccuracies for periodic or quasi-periodic structures
Dual Identities Enabled Low-Latency Visual Networking for UAV Emergency Communication
The Unmanned Aerial Vehicle (UAV) swarm networks will play a crucial role in
the B5G/6G network thanks to its appealing features, such as wide coverage and
on-demand deployment. Emergency communication (EC) is essential to promptly
inform UAVs of potential danger to avoid accidents, whereas the conventional
communication-only feedback-based methods, which separate the digital and
physical identities (DPI), bring intolerable latency and disturb the unintended
receivers. In this paper, we present a novel DPI-Mapping solution to match the
identities (IDs) of UAVs from dual domains for visual networking, which is the
first solution that enables UAVs to communicate promptly with what they see
without the tedious exchange of beacons. The IDs are distinguished dynamically
by defining feature similarity, and the asymmetric IDs from different domains
are matched via the proposed bio-inspired matching algorithm. We also consider
Kalman filtering to combine the IDs and predict the states for accurate
mapping. Experiment results show that the DPI-Mapping reduces individual
inaccuracy of features and significantly outperforms the conventional
broadcast-based and feedback-based methods in EC latency. Furthermore, it also
reduces the disturbing messages without sacrificing the hit rate.Comment: 6 pages, 6 figure
Specific Beamforming for Multi-UAV Networks: A Dual Identity-based ISAC Approach
Beam alignment is essential to compensate for the high path loss in the
millimeter-wave (mmWave) Unmanned Aerial Vehicle (UAV) network. The integrated
sensing and communication (ISAC) technology has been envisioned as a promising
solution to enable efficient beam alignment in the dynamic UAV network.
However, since the digital identity (D-ID) is not contained in the reflected
echoes, the conventional ISAC solution has to either periodically feed back the
D-ID to distinguish beams for multi-UAVs or suffer the beam errors induced by
the separation of D-ID and physical identity (P-ID). This paper presents a
novel dual identity association (DIA)-based ISAC approach, the first solution
that enables specific, fast, and accurate beamforming towards multiple UAVs. In
particular, the P-IDs extracted from echo signals are distinguished dynamically
by calculating the feature similarity according to their prevalence, and thus
the DIA is accurately achieved. We also present the extended Kalman filtering
scheme to track and predict P-IDs, and the specific beam is thereby effectively
aligned toward the intended UAVs in dynamic networks. Numerical results show
that the proposed DIA-based ISAC solution significantly outperforms the
conventional methods in association accuracy and communication performance.Comment: 7 pages, 8 figure
Small intestinal submucosa promotes angiogenesis via the Hippo pathway to improve vaginal repair
Vaginal reconstruction has incorporated the use of gastrointestinal segments for decades, but the technique is inevitably associated with complications. Tissue-engineering techniques, however, have brought great hope for vaginal reconstruction. This study aimed to evaluate the utility of small intestinal submucosa (SIS) in reconstructing clinically significant large vaginal defects in a porcine model and to investigate the role of the Hippo pathway in the vascular remodeling process. The composition and mechanical properties of SIS were characterized. Full-thickness vaginal defects were established in 10 minipig donors, with 4 cm lengths removed and replaced by an equal sized SIS scaffolds. The neovaginas were subjected to macroscopic, histological, immunohistochemical and molecular evaluations at 4 and 12 weeks after the surgery. Four weeks after the operation, extracellular matrix reorganization and complete coverage of the surface of the luminal matrix by vaginal epithelium were observed, accompanied by the formation of a microvascular network and the regeneration of smooth muscles, albeit disorderly arranged. Twelve weeks after implantation, enhancements were seen in the formation of the multi-layered squamous epithelium, angiogenesis, and large muscle bundle formation in the vagina. Additionally, the expression levels of angiogenesis-related proteins, proliferation-related proteins and Hippo pathway-related proteins in the neovagina were significantly increased. These results indicate that SIS could be used to reconstruct large vaginal defects and that the vascular remodeling process is potentially regulated by the Hippo pathway
Pressure-induced superconductivity and topological quantum phase transitions in a quasi-one-dimensional topological insulator: Bi4I4
Superconductivity and topological quantum states are two frontier fields of
research in modern condensed matter physics. The realization of
superconductivity in topological materials is highly desired, however,
superconductivity in such materials is typically limited to two- or
three-dimensional materials and is far from being thoroughly investigated. In
this work, we boost the electronic properties of the quasi-one-dimensional
topological insulator bismuth iodide \b{eta}-Bi4I4 by applying high pressure.
Superconductivity is observed in \b{eta}-Bi4I4 for pressures where the
temperature dependence of the resistivity changes from a semiconducting-like
behavior to that of a normal metal. The superconducting transition temperature
Tc increases with applied pressure and reaches a maximum value of 6 K at 23
GPa, followed by a slow decrease. Our theoretical calculations suggest the
presence of multiple pressure-induced topological quantum phase transitions as
well as a structural-electronic instability.Comment: 22 pages, 4 figures, submitted to journa
Disordered structure for long-range charge density wave order in annealed crystals of magnetic kagome FeGe
Recently, charge density wave (CDW) has been observed well below the order of
antiferromagnetism (AFM) in kagome FeGe in which magnetism and CDW are
intertwined to form an emergent quantum ground state. The mechanism of CDW
precipitating from an A-type AFM of Fe kagome sublattice is intensively
debated. The structural distortion originating from the CDW has yet to be
accurately determined in FeGe. Here we resolved the structure model of the CDW
in annealed FeGe crystals through single crystal x-ray diffraction via a
synchrotron radiation source. The annealed crystals exhibit strong CDW
transition signals exemplified by sharp magnetic susceptibility drop and
specific heat jump, as well as intense superlattice reflections from 2
2 2 CDW order. Occupational disorder of Ge atoms resulting from
short-range CDW correlations above has also been identified
from the structure refinements. The dimerization of Ge atoms along c axis has
been demonstrated to be the dominant distortion for CDW. The Fe kagome and Ge
honeycomb sublattices only undergo subtle distortions. Occupational disorder of
Ge atoms is also proved to exist in the CDW phase due to the random selection
of partial Ge sites to be dimerized to realize the structural distortion. Our
work paves the way to understanding the unconventional nature of CDW in FeGe
not only by solving the structural distortion below and
identifying fluctuations above it but also by rationalizing the synthesis of
high-quality crystals for in-depth investigations in the future.Comment: 18 pages, 4 figures. Comments are welcom
Metabolomics in the Development and Progression of Dementia: A Systematic Review
Dementia has become a major global public health challenge with a heavy economic burden. It is urgently necessary to understand dementia pathogenesis and to identify biomarkers predicting risk of dementia in the preclinical stage for prevention, monitoring, and treatment. Metabolomics provides a novel approach for the identification of biomarkers of dementia. This systematic review aimed to examine and summarize recent retrospective cohort human studies assessing circulating metabolite markers, detected using high-throughput metabolomics, in the context of disease progression to dementia, including incident mild cognitive impairment, all-cause dementia, and cognitive decline. We systematically searched the PubMed, Embase, and Cochrane databases for retrospective cohort human studies assessing associations between blood (plasma or serum) metabolomics profile and cognitive decline and risk of dementia from inception through October 15, 2018. We identified 16 studies reporting circulating metabolites and risk of dementia, and six regarding cognitive performance change. Concentrations of several blood metabolites, including lipids (higher phosphatidylcholines, sphingomyelins, and lysophophatidylcholine, and lower docosahexaenoic acid and high-density lipoprotein subfractions), amino acids (lower branched-chain amino acids, creatinine, and taurine, and higher glutamate, glutamine, and anthranilic acid), and steroids were associated with cognitive decline and the incidence or progression of dementia. Circulating metabolites appear to be associated with the risk of dementia. Metabolomics could be a promising tool in dementia biomarker discovery. However, standardization and consensus guidelines for study design and analytical techniques require future development
Disorder Improves Light Absorption in Thin Film Silicon Solar Cells with Hybrid Light Trapping Structure
We present a systematic simulation study on the impact of disorder in thin film silicon solar cells with hybrid light trapping structure. For the periodical structures introducing certain randomness in some parameters, the nanophotonic light trapping effect is demonstrated to be superior to their periodic counterparts. The nanophotonic light trapping effect can be associated with the increased modes induced by the structural disorders. Our study is a systematic proof that certain disorder is conceptually an advantage for nanophotonic light trapping concepts in thin film solar cells. The result is relevant to the large field of research on nanophotonic light trapping which currently investigates and prototypes a number of new concepts including disordered periodic and quasiperiodic textures. The random effect on the shape of the pattern (position, height, and radius) investigated in this paper could be a good approach to estimate the influence of experimental inaccuracies for periodic or quasi-periodic structures
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