1,603 research outputs found
Anisotropic magnetoresistance in antiferromagnetic Sr2IrO4
We report point-contact measurements of anisotropic magnetoresistance (AMR)
in a single crystal of antiferromagnetic (AFM) Mott insulator Sr2IrO4. The
point-contact technique is used here as a local probe of magnetotransport
properties on the nanoscale. The measurements at liquid nitrogen temperature
revealed negative magnetoresistances (MRs) (up to 28%) for modest magnetic
fields (250 mT) applied within the IrO2 a-b plane and electric currents flowing
perpendicular to the plane. The angular dependence of MR shows a crossover from
four-fold to two-fold symmetry in response to an increasing magnetic field with
angular variations in resistance from 1-14%. We tentatively attribute the
four-fold symmetry to the crystalline component of AMR and the field-induced
transition to the effects of applied field on the canting of AFM-coupled
moments in Sr2IrO4. The observed AMR is very large compared to the crystalline
AMRs in 3d transition metal alloys/oxides (0.1-0.5%) and can be associated with
the large spin-orbit interactions in this 5d oxide while the transition
provides evidence of correlations between electronic transport, magnetic order
and orbital states. The finding of this work opens an entirely new avenue to
not only gain a new insight into physics associated with spin-orbit coupling
but also better harness the power of spintronics in a more technically
favorable fashion.Comment: 13 pages, 3 figure
Human Transcription Quality Improvement
High quality transcription data is crucial for training automatic speech
recognition (ASR) systems. However, the existing industry-level data collection
pipelines are expensive to researchers, while the quality of crowdsourced
transcription is low. In this paper, we propose a reliable method to collect
speech transcriptions. We introduce two mechanisms to improve transcription
quality: confidence estimation based reprocessing at labeling stage, and
automatic word error correction at post-labeling stage. We collect and release
LibriCrowd - a large-scale crowdsourced dataset of audio transcriptions on 100
hours of English speech. Experiment shows the Transcription WER is reduced by
over 50%. We further investigate the impact of transcription error on ASR model
performance and found a strong correlation. The transcription quality
improvement provides over 10% relative WER reduction for ASR models. We release
the dataset and code to benefit the research community.Comment: 5 pages, 3 figures, 5 tables, INTERSPEECH 202
(Methanolato)(pyridine)[N 2,N 2′-(pyridine-2,6-diyldicarbonÂyl)diacetohydraÂzide(2–)]iron(III) methanol solvate
In the title complex, [Fe(C11H10N5O4)(CH3O)(C5H5N)]·CH4O, the FeIII ion has a distorted pentaÂgonal-bipyramidal geometry. In the crystal structure, molÂecules are linked into one-dimensional chains along [1
] via interÂmolecular O—H⋯O and N—H⋯O hydrogen bonds
Hydrocarbon origin and reservoir forming model research of Longwangmiao Formation, Moxi-Gaoshiti area, Sichuan Basin
AbstractThis paper focuses on the Longwangmiao gas reservoir in Moxi-Gaoshiti area, Sichuan Basin. Starting from the tectonic evolution perspective, though comparing biological marker compound and analyzing fluid inclusions, the oil & gas origin and accumulation evolution of Longwangmiao Formation are systematic studied with reference to the burial-thermal evolution of single well geological history in the study area. It is suggested that the oil & gas reservoir is generally characterized by early accumulation, multi-stage filling, late cracking and later adjustment. The oil and gas were mainly sourced from lower Cambrian Qiongzhusi Formation, partly from the Permian source rock. During the geological period, 3 major oil & gas fillings occurred in the Longwangmiao Formation, namely Caledonian-Hercynian filling that was small in scale and produced the first phase of paleo-oil reservoir that soon destroyed by Caledonian movement uplift, large-scale Permian filling that gave rise to the second-phase of paleo-oil reservoir and the Triassic-Jurassic filling that enriched the second phase of paleo-oil reservoir. Finally, the paleo-oil reservoir experienced an in-situ cracking during the cretaceous period that gave rise to a natural gas reservoir and left behind carbonaceous bitumen and oily bitumen in the holes of the Longwangmiao Formation
On the external photon fields in Fermi bright blazars
The external Compton (EC) model is used to study the high energy emission of
some blazars, in which the external photon field is considered to dominate
inverse Compton radiation. We explore the properties of external photon field
through analyzing the FERMI LAT bright AGN sample within three months
detection. In the sample, assuming the high energy radiation of low synchrotron
peaked blazars from the EC process, we find that the external photon parameter
Uext/\nuext may not be a constant. Calculating synchrotron and inverse Compton
(IC) luminosity from the quasi-simultaneous broadband spectrum energy
distributions (SEDs), we find that they have an approximately linear relation.
This indicates that the ratio of external photon and magnetic energy density is
a constant in the comoving frame, implying that the Lorentz factor of the
emitting blob depends on external photon field and magnetic field. The result
gives a strong constraint on the jet dynamic model.Comment: 7 pages, 2 figure
Temporal Action Localization with Enhanced Instant Discriminability
Temporal action detection (TAD) aims to detect all action boundaries and
their corresponding categories in an untrimmed video. The unclear boundaries of
actions in videos often result in imprecise predictions of action boundaries by
existing methods. To resolve this issue, we propose a one-stage framework named
TriDet. First, we propose a Trident-head to model the action boundary via an
estimated relative probability distribution around the boundary. Then, we
analyze the rank-loss problem (i.e. instant discriminability deterioration) in
transformer-based methods and propose an efficient scalable-granularity
perception (SGP) layer to mitigate this issue. To further push the limit of
instant discriminability in the video backbone, we leverage the strong
representation capability of pretrained large models and investigate their
performance on TAD. Last, considering the adequate spatial-temporal context for
classification, we design a decoupled feature pyramid network with separate
feature pyramids to incorporate rich spatial context from the large model for
localization. Experimental results demonstrate the robustness of TriDet and its
state-of-the-art performance on multiple TAD datasets, including hierarchical
(multilabel) TAD datasets.Comment: An extended version of the CVPR paper arXiv:2303.07347, submitted to
IJC
Understanding the chemical evolution of blue Edge-on Low Surface Brightness Galaxies
We present a sample of 330 blue edge-on low surface brightness galaxies
(ELSBGs). To understand the chemical evolution of LSBGs, we derived the
gas-phase abundance and the [/Fe] ratio. Compared with star-forming
galaxies, ELSBGs show a flatter trend in the mass-metallicity ()
relation, suggesting that the oxygen abundance enhancement is inefficient. We
focus on 77 ELSBGs with HI data and found the closed-box model can not explain
their gas fraction and metallicity relation, implying that infall and/or
outflow is needed. We derived the [/Fe] ratio of normal ELSBG (
10M) and massive ELSBG ( 10M) using single
stellar population grids from MILES stellar library. The mean [/Fe]
ratios are 0.18 and 0.4 for normal ELSBG and massive ELSBG, respectively. We
discussed that the long time-scale of star-formation, and/or metal-rich gas
outflow event caused by SNe Ia winds are likely responsible for the
-enhancement of massive ELSBGs.Comment: 9 pages, 9 figures, Accepted for publication in Ap
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