7,246 research outputs found
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
Unsupervised multi-modal style transfer for cardiac MR segmentation
In this work, we present a fully automatic method to segment cardiac structures from late-gadolinium enhanced (LGE) images without using labelled LGE data for training, but instead by transferring the anatomical knowledge and features learned on annotated balanced steady-state free precession (bSSFP) images, which are easier to acquire. Our framework mainly consists of two neural networks: a multi-modal image translation network for style transfer and a cascaded segmentation network for image segmentation. The multi-modal image translation network generates realistic and diverse synthetic LGE images conditioned on a single annotated bSSFP image, forming a synthetic LGE training set. This set is then utilized to fine-tune the segmentation network pre-trained on labelled bSSFP images, achieving the goal of unsupervised LGE image segmentation. In particular, the proposed cascaded segmentation network is able to produce accurate segmentation by taking both shape prior and image appearance into account, achieving an average Dice score of 0.92 for the left ventricle, 0.83 for the myocardium, and 0.88 for the right ventricle on the test set
The 7-channel FIR HCN Interferometer on J-TEXT Tokamak
A seven-channel far-infrared hydrogen cyanide (HCN) laser interferometer has
been established aiming to provide the line integrated plasma density for the
J-TEXT experimental scenarios. A continuous wave glow discharge HCN laser
designed with a cavity length 3.4 m is used as the laser source with a
wavelength of 337 {\mu}m and an output power up to 100 mW. The system is
configured as a Mach-Zehnder type interferometer. Phase modulation is achieved
by a rotating grating, with a modulation frequency of 10 kHz which corresponds
to the temporal resolution of 0.1 ms. The beat signal is detected by TGS
detector. The phase shift induced by the plasma is derived by the comparator
with a phase sensitivity of 0.06 fringe. The experimental results measured by
the J-TEXT interferometer are presented in details. In addition, the inversed
electron density profile done by a conventional approach is also given. The
kinematic viscosity of dimethyl silicone and vibration control is key issues
for the system performance. The laser power stability under different kinematic
viscosity of silicone oil is presented. A visible improvement of measured
result on vibration reduction is shown in the paper.Comment: conference (15th-International Symposium on Laser-Aided Plasma
Diagnostics
Numerical simulation of water waves interacting with elastic ice floes
摘要:本文围绕弹性冰群与波浪相互作用问题,建立了基于 OpenFOAM 开源软件的数值
计算模型,实现了流体与弹性浮冰耦合运动的双向迭代求解,并以规则波与两片弹性浮冰
的相互作用为例,分析了浮冰间距和浮冰刚度等参数对二维波浪传播特性的影响。研究发
现,在所考虑的参数范围内,刚度越大、间距越小的两块浮冰,对应的波浪反射系数越小、
透射系数越大,并且波浪反射系数的减小幅度大于透射系数的增加幅度。
关键词:OpenFOAM;流固耦合;浮冰;波物作用;水弹
GaSb quantum rings in GaAs/AlxGa1−xAs quantum wells
We report the results of continuous and time-resolved photoluminescence measurements on type-II GaSb quantum rings embedded within GaAs/AlxGa1-xAs quantum wells. A range of samples were grown with different well widths, compensation-doping concentrations within the wells, and number of quantum-ring layers. We find that each of these variants have no discernible effect on the radiative recombination, except for the very narrowest (5 nm) quantum well. In contrast, singleparticle numerical simulations of the sample predict changes in photoluminescence energy of up to 200 meV. This remarkable difference is explained by the strong Coulomb binding of electrons to rings that are multiply charged with holes. The resilience of the emission to compensation doping indicates that multiple hole occupancy of the quantum rings is required for efficient carrier recombination, regardless of whether these holes come from doping or excitation
Multi-Modality Pathology Segmentation Framework: Application to Cardiac Magnetic Resonance Images
Multi-sequence of cardiac magnetic resonance (CMR) images can provide
complementary information for myocardial pathology (scar and edema). However,
it is still challenging to fuse these underlying information for pathology
segmentation effectively. This work presents an automatic cascade pathology
segmentation framework based on multi-modality CMR images. It mainly consists
of two neural networks: an anatomical structure segmentation network (ASSN) and
a pathological region segmentation network (PRSN). Specifically, the ASSN aims
to segment the anatomical structure where the pathology may exist, and it can
provide a spatial prior for the pathological region segmentation. In addition,
we integrate a denoising auto-encoder (DAE) into the ASSN to generate
segmentation results with plausible shapes. The PRSN is designed to segment
pathological region based on the result of ASSN, in which a fusion block based
on channel attention is proposed to better aggregate multi-modality information
from multi-modality CMR images. Experiments from the MyoPS2020 challenge
dataset show that our framework can achieve promising performance for
myocardial scar and edema segmentation.Comment: 12 pages,MyoPS 202
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