3,663 research outputs found
Theory of electronic properties and quantum spin blockade in a gated linear triple quantum dot with one electron spin each
We present a theory of electronic properties and the spin blockade phenomena
in a gated linear triple quantum dot. Quadruple points where four different
charge configurations are on resonance, particularly involving (1,1,1)
configuration, are considered. In the symmetric case, the central dot is biased
to higher energy and a single electron tunnels through the device when (1,1,1)
configuration is resonant with (1,0,1),(2,0,1),(1,0,2) configurations. The
electronic properties of a triple quantum dot are described by a Hubbard model
containing two orbitals in the two unbiased dots and a single orbital in the
biased dot. The transport through the triple quantum dot molecule involves both
singly and doubly occupied configurations and necessitates the description of
the (1,1,1) configuration beyond the Heisenberg model. Exact eigenstates of the
triple quantum dot molecule with up to three electrons are used to compute
current assuming weak coupling to the leads and non-equilibrium occupation of
quantum molecule states obtained from the rate equation. The intra-molecular
relaxation processes due to acoustic phonons and cotunneling with the leads are
included, and are shown to play a crucial role in the spin blockade effect. We
find a quantum interference-based spin blockade phenomenon at low source-drain
bias and a distinct spin blockade due to a trap state at higher bias. We also
show that, for an asymmetric quadruple point with
(0,1,1),(1,1,1,),(0,2,1),(0,1,2) configurations on resonance, the spin blockade
is analogous to the spin blockade in a double quantum dot
Improving Small Footprint Few-shot Keyword Spotting with Supervision on Auxiliary Data
Few-shot keyword spotting (FS-KWS) models usually require large-scale
annotated datasets to generalize to unseen target keywords. However, existing
KWS datasets are limited in scale and gathering keyword-like labeled data is
costly undertaking. To mitigate this issue, we propose a framework that uses
easily collectible, unlabeled reading speech data as an auxiliary source.
Self-supervised learning has been widely adopted for learning representations
from unlabeled data; however, it is known to be suitable for large models with
enough capacity and is not practical for training a small footprint FS-KWS
model. Instead, we automatically annotate and filter the data to construct a
keyword-like dataset, LibriWord, enabling supervision on auxiliary data. We
then adopt multi-task learning that helps the model to enhance the
representation power from out-of-domain auxiliary data. Our method notably
improves the performance over competitive methods in the FS-KWS benchmark.Comment: Interspeech 202
PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE
Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD) is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure
Clinical Characteristics and Genotypes of Rotaviruses in a Neonatal Intensive Care Unit
BackgroundThere are few reports on the symptoms of rotavirus infections in neonates. This study aims to describe clinical signs of rotavirus infections among neonates, with a particular focus on preterm infants, and to show the distribution of genotypes in a neonatal intensive care unit (NICU).MethodsA prospective observational study was conducted at a regional NICU for 1 year. Stool specimens from every infant in the NICU were collected on admission, at weekly intervals, and from infants showing symptoms. Rotavirus antigens were detected by enzyme-linked immunosorbent assay (ELISA), and genotypes were confirmed by Reverse transcription-Polymerase chain reaction (RT-PCR). The infants were divided into three groups: symptomatic preterm infants with and without rotavirus-positive stools [Preterm(rota+) and Preterm(rotaâ), respectively] and symptomatic full- or near-term infants with rotavirus-positive stools [FT/NT(rota+)]. Demographic and outcome data were compared among these groups.ResultsA total of 702 infants were evaluated for rotaviruses and 131 infants were included in this study. The prevalence of rotavirus infections was 25.2%. Preterm(rota+) differed from Preterm(rotaâ) and FT/NT(rota+) with respect to frequent feeding difficulty (p = 0.047 and 0.034, respectively) and higher percentage of neutropenia (p = 0.008 and 0.011, respectively). G4P[6] was the exclusive strain in both the Preterm(rota+) (97.7%) and FT/NT(rota+) (90.2%), and it was the same for nosocomial, institutional infections, and infections acquired at home.ConclusionSystemic illness signs such as feeding difficulty and neutropenia are specific for preterm infants with rotavirus infections. G4P[6] was exclusive, regardless of preterm birth or locations of infections. This study might be helpful in developing policies for management and prevention of rotavirus infections in NICUs
Surface morphology and I-V characteristics of single crystal, polycrystalline and amorphous silicon FEAs
ABSTRACT This paper reports surface morphology and I-V characteristics of single crystal silicon(c-Si), polycrystalline silicon(polySi) and amorphous silicon(a-Si) field emitter arrays(FEAs). As-deposited a-Si film has smoother surface than poly-Si film. The surface morphology of the a-Si remains smooth after phosphorus doping and 950°C oxidation. a-Si FEAs have improved emission characteristics i. e. smaller anode current deviation among arrays, smaller gate current, and higher failure voltage than poly-Si FEAs. Such improved characteristics can be explained by the smooth surface morphology which is kept during doping and oxidation. The surface roughness and emission characteristics of a-Si FEAs are comparable to those of c-Si FEAs
Y a-t-il « activation » des politiques sociales en Corée du Sud ?
Quelles sont les spĂ©cificitĂ©s des politiques de protection sociale de CorĂ©e du sud, analysĂ©es dans la perspective de leur activation ? Lâarticle sâappuie sur trois critĂšres considĂ©rĂ©s comme caractĂ©ristiques de lâactivation : la connexion entre les politiques de protection sociale et celles dâautres domaines (emploi ou fiscalitĂ©) ; lâexistence de dispositifs incitatifs (rĂ©compense ou punition) de prestations en Ă©change de la participation ou non aux programmes dâinclusion offerts par lâĂtat ; enfin, le rĂŽle de lâĂtat, non seulement dans le progrĂšs de lâaptitude Ă lâemploi de lâindividu, mais aussi dans la crĂ©ation des emplois en tant quâemployeur de dernier ressort. Il nâest pas Ă©vident quâen CorĂ©e du sud, il y ait une politique dâactivation dans le domaine social, particuliĂšrement dans celui de la protection sociale. Lâactivation en CorĂ©e du Sud pourrait en effet relever dâun « rĂ©gime rudimentaire », dans le sens oĂč elle ne concerne, selon la typologie de J.-C. Barbier, ni le rĂ©gime libĂ©ral, ni le rĂ©gime social-dĂ©mocrate universaliste et oĂč elle commence Ă se mettre en place dans le domaine social.Which are particularities of social policies of the Republic of Korea, analyzed according to the comparative perspective of the activation? In order to find one response to this question, we have analyzed its policies of social domain and particularly that of social protection, based on the three criteria considered as characters of âactivationâ: the relation between social protection policies and the policies of another domain (ex. employment or taxation); the incentive rules of the benefits (reward or punishment) in exchange of the participation (or no-participation) in the social integration programs, offered by the State; the role of State, not only in the progress of employability of the individual, but in the creation of social job, including the social enterprise. In conclusion, it is not evident that, in the Republic of Korea, the activation policies settle down in itself in the domain of social policies and particularly in that of social protection policies. As type of regime, we would call the activation in the Korea ârudimentary regimeâ, in the sense that, according to the typology of the activation regime elaborated by the J.-C. Barbier, it does not concern with the liberal regime and nor does the social-democratic universalistic regime, and that it is on the way to settle down in the social policies
KINEMATIC SYNTHESIS OF A MEDICAL BED FOR DECUBITUS ULCER PATIENTS
ABSTRACT A decubitus ulcer or bedsore is a pressure-induced ulceration of the skin occurring in persons confined to bed for long periods of time. Reduction of pressure over bony prominences is of primary importance to prevent and cure bedsores. For this purpose, specially designed mattresses can be used and/or the patient should be turned frequently to avoid ischemia of soft tissue. In addition to pressure, other principal factors causing bedsore are friction and shear forces. In this paper, we designed a new 5 degree of freedom bed mechanism that can be used to change the posture of pressure ulcer patients, which generates 7 motions including backrest elevation, kneerest elevation, lounge position, left and right rotation, trendelenberg and reverse trendelenberg motion, and straight elevation. Particularly, we focused on the synthesis of a backrest and seatrest assembly that can reduce sliding between the bed and the patient
Clinical outcomes for T1-2N0-1 oral tongue cancer patients underwent surgery with and without postoperative radiotherapy
BACKGROUND: The aim of this study was to assess the results of curative surgery with and without radiotherapy in patients with T1-2N0-1 oral tongue squamous cell carcinoma (OSCC) and to evaluate survival and prognostic factors.
METHODS: Retrospective analysis of 86 patients with T1-2N0-1 OSCC who received surgery between January 2000 and December 2006. Fourteen patients (16.3%) received postoperative radiotherapy (PORT). Patient characteristics, tumor characteristics, treatment modality, failure patterns, and survival rates were analyzed.
RESULTS: The median follow-up was 45 months. The five-year overall survival (OS) and disease-free survival (DFS) rates were 80.8% and 80.2%, respectively. Higher tumor grade and invasion depth > or = 0.5 cm were the significant prognostic factors affecting five-year OS and DFS (OS rate; 65% vs. 91%, p = 0.001 for grade; 66% vs. 92%, p = 0.01 for invasion depth: DFS rate; 69% vs. 88%, p = 0.005 for grade; 66% vs. 92%, p = 0.013 for invasion depth). In the risk group, there was no local failure in patients with postoperative radiotherapy.
CONCLUSIONS: In T1-2N0-1 OSCC, factors that affected prognosis after primary surgery were higher tumor grade and deep invasion depth over 0.5 cm. Postoperative radiotherapy should be considered in early oral tongue cancer patients with these high-risk pathologic featuresope
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