177 research outputs found
Endobronchial Lipoma: An Unusual Cause of Bronchial Obstruction
Endobronchial lipoma is a rare benign tumor. It is difficult to differentiate benign endobronchial lipoma from their malignant counterparts, as their symptoms and complications are almost alike. Here, we describe the clinical and radiological features of EL in two cases. Multislice CT (MSCT) may play an important role in the diagnosis for EL
A direct unified wave-particle method for simulating non-equilibrium flows
In this work, the Navier-Stokes (NS) solver is combined with the Direct
simulation Monte Carlo (DSMC) solver in a direct way, under the wave-particle
formulation [J. Comput. Phys. 401, 108977 (2020)]. Different from the classical
domain decomposition method with buffer zone for overlap, in the proposed
direct unified wave-particle (DUWP) method, the NS solver is coupled with DSMC
solver on the level of algorithm. Automatically, in the rarefied flow regime,
the DSMC solver leads the simulation, while the NS solver leads the continuum
flow simulation. Thus advantages of accuracy and efficiency are both taken. At
internal flow regimes, like the transition flow regime, the method is accurate
as well because a kind of mesoscopic modeling is proposed in this work, which
gives the DUWP method the multi-scale property. Specifically, as to the
collision process, at , it is supposed that only single collision
happens, and the collision term of DSMC is just used. At , it is
derived that of particles should experience multiple
collisions, which will be absorbed into the wave part and calculated by the NS
solver. Then the DSMC and NS solver can be coupled in a direct and simple way,
bringing about multi-scale property. The governing equation is derived and
named as multi-scale Boltzmann equation. Different from the original
wave-particle method, in the proposed DUWP method, the wave-particle
formulation is no more restricted by the Boltzmann-BGK type model and the
enormous research findings of DSMC and NS solvers can be utilized into much
more complicated flows, like the thermochemical non-equilibrium flow. In this
work, one-dimensional cases in monatomic argon gas are preliminarily tested,
such as shock structures and Sod shock tubes
Orthogonal Spatial Coding with Stimulated Parametric Down-Conversion
Orthogonal optical coding is widely used in classical multiuser communication
networks. Using the phase conjugation property of stimulated parametric
down-conversion, we extend the current orthogonal optical coding scheme to the
spatial domain to encode and decode image information. In this process, the
idler beam inherits the complex conjugate of the field information encoded in
the seed beam. An encoding phase mask introduced to the input seed beam blurs
the image transferred to the idler. The original image is restored by passing
the coded transferred image through a corrective phase mask placed in the
momentum space of the idler beam. We expect that this scheme can also inspire
new techniques in aberration cancellation and frequency conversion imaging
A Secure and Efficient Multi-Object Grasping Detection Approach for Robotic Arms
Robotic arms are widely used in automatic industries. However, with wide
applications of deep learning in robotic arms, there are new challenges such as
the allocation of grasping computing power and the growing demand for security.
In this work, we propose a robotic arm grasping approach based on deep learning
and edge-cloud collaboration. This approach realizes the arbitrary grasp
planning of the robot arm and considers the grasp efficiency and information
security. In addition, the encoder and decoder trained by GAN enable the images
to be encrypted while compressing, which ensures the security of privacy. The
model achieves 92% accuracy on the OCID dataset, the image compression ratio
reaches 0.03%, and the structural difference value is higher than 0.91
Seeing the Unheard: dynamics of thin liquid film in holographic ultrasonic field revealed by time-resolved Schlieren imaging
In this study, we introduce a unique approach that employs time-resolved
Schlieren imaging to capture and visualize the dynamic changes of a thin liquid
(mixture of water, soap and glycerin) film in ultrasonic wave field with high
spatial and temporal resolution. By placing a soap film spanning a wire frame
vertically in the path of light, we harnessed the vibrations induced by the
ultrasonic waves, resulting in remarkable Schlieren imaging patterns. The
investigation not only uncovers an unexpected branch flow phenomenon within the
film, challenging existing assumptions, but also reveals a fascinating
interplay between vortex flow and branch flow. The experiments have revealed a
captivating spectrum of dynamic phenomena within the thin liquid films. The
observation of small-scale capillary waves, large-scale standing waves,
traveling waves, and the intricate fusion of capillary-gravity wave patterns
underscores the rich complexity inherent in the interaction between the films
and the holographic ultrasonic wave field. These diverse states of film
dynamics provide a comprehensive understanding of the intricate interplay
between various wave modes and fluid behavior, further enhancing comprehension
of this fascinating phenomenon. The ability to visualize the pressure field
opens up new avenues for optimizing acoustic levitation techniques,
investigating particle behavior, and exploring potential applications in
materials science and bioengineering.Comment: 10 pages, 8 page
Multiscale Superpixel Structured Difference Graph Convolutional Network for VL Representation
Within the multimodal field, the key to integrating vision and language lies
in establishing a good alignment strategy. Recently, benefiting from the
success of self-supervised learning, significant progress has been made in
multimodal semantic representation based on pre-trained models for vision and
language. However, there is still room for improvement in visual semantic
representation. The lack of spatial semantic coherence and vulnerability to
noise makes it challenging for current pixel or patch-based methods to
accurately extract complex scene boundaries. To this end, this paper develops
superpixel as a comprehensive compact representation of learnable image data,
which effectively reduces the number of visual primitives for subsequent
processing by clustering perceptually similar pixels. To mine more precise
topological relations, we propose a Multiscale Difference Graph Convolutional
Network (MDGCN). It parses the entire image as a fine-to-coarse hierarchical
structure of constituent visual patterns, and captures multiscale features by
progressively merging adjacent superpixels as graph nodes. Moreover, we predict
the differences between adjacent nodes through the graph structure,
facilitating key information aggregation of graph nodes to reason actual
semantic relations. Afterward, we design a multi-level fusion rule in a
bottom-up manner to avoid understanding deviation by learning complementary
spatial information at different regional scales. Our proposed method can be
well applied to multiple downstream task learning. Extensive experiments
demonstrate that our method is competitive with other state-of-the-art methods
in visual reasoning. Our code will be released upon publication
A Window of MHM Demethylation Correlates with Key Events in Gonadal Differentiation in the Chicken
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