1,453 research outputs found
Formation of hot subdwarf B stars with neutron star components
Binary population synthesis predicts the existence of subdwarf B stars (sdBs)
with neutron star (NS) or black hole (BH) companions. We systematically
investigate the formation of sdB+NS binaries from binary evolution and aim to
obtain some clues for a search for such systems. We started from a series of
MS+NS systems and determined the parameter spaces for producing sdB+NS binaries
from the stable Roche-lobe overflow (RLOF) channel and from the common envelope
(CE) ejection channel. Various NS accretion efficiencies and NS masses were
examined to investigate the effects they have. We show the characteristics of
the produced sdB+NS systems, such as the mass of components, orbital period,
the semi-amplitude of the radial velocity (K), and the spin of the NS
component. In the stable RLOF channel, the orbital period of sdB+NS binaries
produced in this way ranges from several days to more than 1000 days and moves
toward the short-period (~ hr) side with increasing initial MS mass. the sdB+NS
systems that result from CE ejection have very short orbital periods and then
high values of K (up to 800km s^-1). Such systems are born in very young
populations (younger than 0.3 Gyr) and are potential gravitational wave sources
that might be resolved by the Laser Interferometer Space Antenna (LISA) in the
future. Gravitational wave radiation may again bring them into contact on a
timescale of only ~Myr. As a consequence, they are rare and hard to discover.
The pulsar signal is likely a feature of sdB+NS systems caused by stable RLOF,
and some NS components in sdB binaries may be millisecond pulsars.Comment: 12 pages, 6 figures, 4 tables. Accepted for publication in A&
at CEPC: ISR effect with MadGraph
The Circular Electron Positron Collider (CEPC) is a future Higgs factory
proposed by the Chinese high energy physics community. It will operate at a
center-of-mass energy of 240-250 GeV. The CEPC will accumulate an integrated
luminosity of 5 ab in ten years' operation. With GEANT4-based full
simulation samples for CEPC, Higgs boson decaying into electron pair is studied
at the CEPC. The upper limit of could reach
0.024\% at 95\% confidence level. The signal process is generated by MadGraph,
with Initial State Radiation (ISR) implemented, as a first step to adjust
MadGraph for a electron positron Collider.Comment: Accepted version by J.P.
Effects of fan volute structure on airflow characteristics in rice combine harvesters
Aim of study: Selecting a proper fan for the rice combine harvesters to get a good cleaning performance when harvesting high yield rice. Area of study: Jiangsu Province, China.Material and methods: Three potential multi-duct fans were designed, and the computational fluid dynamics and hot wire anemometer technology were utilized to learn the airflow and pressure variation inside the fan with perforated plates at the outlet ducts as cleaning loads. Then, the fan with the best performance was selected and a multi-duct cleaning test-bed was developed. The variation of the corresponding airflow velocity in the cleaning system was analyzed and the ideal airflow velocity in different section of the sieve was clarified. Finally, a field experiment was carried out.Main results: For a rice combine harvester with a feed rate of 7 kg/s (material other than grain + grain), the requested airflow rates inside the cleaning shoe was about 3.0 m3/s. The ideal airflow velocity in different section of the cleaning shoe was 8-9 m/s at upper duct, 4-6 m/s at the middle section, and 3-4 m/s at the tail section; large improvement in cleaning performance was achieved with the designed fan.Research highlights: The airflow velocity decreased as the cleaning loads at the duct increased. The fan with the averaged airflow velocity ≥7 m/s at the upper duct under different cleaning loads, and the airflow velocity at the lowest duct ≥ 9 m/s, is favorable for forming a blowing airflow in the tail sieve and is good for grain stratification
Deconfinement Phase Transition in an Expanding Quark system in Relaxation Time Approximation
We investigated the effects of nonequilibrium and collision terms on the
deconfinement phase transition of an expanding quark system in Friedberg-Lee
model in relaxation time approximation. By calculating the effective quark
potential, the critical temperature of the phase transition is dominated by the
mean field, while the collisions among quarks and mesons change the time
structure of the phase transition significantly.Comment: 7 pages, 7 figure
DeepInteraction: 3D Object Detection via Modality Interaction
Existing top-performance 3D object detectors typically rely on the
multi-modal fusion strategy. This design is however fundamentally restricted
due to overlooking the modality-specific useful information and finally
hampering the model performance. To address this limitation, in this work we
introduce a novel modality interaction strategy where individual per-modality
representations are learned and maintained throughout for enabling their unique
characteristics to be exploited during object detection. To realize this
proposed strategy, we design a DeepInteraction architecture characterized by a
multi-modal representational interaction encoder and a multi-modal predictive
interaction decoder. Experiments on the large-scale nuScenes dataset show that
our proposed method surpasses all prior arts often by a large margin.
Crucially, our method is ranked at the first position at the highly competitive
nuScenes object detection leaderboard.Comment: To appear at NeurIPS 2022. 16 pages, 7 figur
UMIFormer: Mining the Correlations between Similar Tokens for Multi-View 3D Reconstruction
In recent years, many video tasks have achieved breakthroughs by utilizing
the vision transformer and establishing spatial-temporal decoupling for feature
extraction. Although multi-view 3D reconstruction also faces multiple images as
input, it cannot immediately inherit their success due to completely ambiguous
associations between unstructured views. There is not usable prior
relationship, which is similar to the temporally-coherence property in a video.
To solve this problem, we propose a novel transformer network for Unstructured
Multiple Images (UMIFormer). It exploits transformer blocks for decoupled
intra-view encoding and designed blocks for token rectification that mine the
correlation between similar tokens from different views to achieve decoupled
inter-view encoding. Afterward, all tokens acquired from various branches are
compressed into a fixed-size compact representation while preserving rich
information for reconstruction by leveraging the similarities between tokens.
We empirically demonstrate on ShapeNet and confirm that our decoupled learning
method is adaptable for unstructured multiple images. Meanwhile, the
experiments also verify our model outperforms existing SOTA methods by a large
margin. Code will be available at https://github.com/GaryZhu1996/UMIFormer.Comment: Accepted by ICCV 202
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