37,694 research outputs found
The Equation of State and Quark Number Susceptibility in Hard-Dense-Loop Approximation
Based on the method proposed in [ H. S. Zong, W. M. Sun, Phys. Rev. \textbf{D
78}, 054001 (2008)], we calculate the equation of state (EOS) of QCD at zero
temperature and finite quark chemical potential under the hard-dense-loop (HDL)
approximation. A comparison between the EOS under HDL approximation and the
cold, perturbative EOS of QCD proposed by Fraga, Pisarski and Schaffner-Bielich
is made. It is found that the pressure under HDL approximation is generally
smaller than the perturbative result. In addition, we also calculate the quark
number susceptibility (QNS) at finite temperature and finite chemical potential
under hard-thermal/dense-loop (HTL/HDL) approximation and compare our results
with the corresponding ones in the previous literature.Comment: 12 pages, 3 figure
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Anharmonic multi-phonon nonradiative transition: An ab initio calculation approach
Nonradiative carrier recombinations at deep centers in semiconductors are of great importance for both fundamental physics and device engineering. In this article, we provide a revised analysis of Huangâs original nonradiative multi-phonon (NMP) theory with ab initio calculations. First, we confirmed at the first-principles level that Huangâs concise formula gives the same results as the matrix-based formula, and that Huangâs high-temperature formula provides an analytical expression for the coupling constant in Marcus theory. Secondly, we correct for anharmonic effects by taking into account local phonon-mode variations for different charge states of a defect. The corrected capture rates for defects in GaN and SiC agree well with experiments
FoveaBox: Beyond Anchor-based Object Detector
We present FoveaBox, an accurate, flexible, and completely anchor-free
framework for object detection. While almost all state-of-the-art object
detectors utilize predefined anchors to enumerate possible locations, scales
and aspect ratios for the search of the objects, their performance and
generalization ability are also limited to the design of anchors. Instead,
FoveaBox directly learns the object existing possibility and the bounding box
coordinates without anchor reference. This is achieved by: (a) predicting
category-sensitive semantic maps for the object existing possibility, and (b)
producing category-agnostic bounding box for each position that potentially
contains an object. The scales of target boxes are naturally associated with
feature pyramid representations. In FoveaBox, an instance is assigned to
adjacent feature levels to make the model more accurate.We demonstrate its
effectiveness on standard benchmarks and report extensive experimental
analysis. Without bells and whistles, FoveaBox achieves state-of-the-art single
model performance on the standard COCO and Pascal VOC object detection
benchmark. More importantly, FoveaBox avoids all computation and
hyper-parameters related to anchor boxes, which are often sensitive to the
final detection performance. We believe the simple and effective approach will
serve as a solid baseline and help ease future research for object detection.
The code has been made publicly available at
https://github.com/taokong/FoveaBox .Comment: IEEE Transactions on Image Processing, code at:
https://github.com/taokong/FoveaBo
Shallow depth of the tunnel excavation response research based on CRD method
AbstractMost bids of Dalian Metro are carried out with shallow tunneling method. However, for the section of Xianggong Street Station of Line 2, the geologic condition, which is mainly composed of strong-weathered rock, is so poor that it brings great difficulties in tunnel excavation. To solve the problem of stability of surrounding rock, numerical simulation and field monitoring are used to analysis the displacement field, stress field and plastic zone in every step of construction which use CRD method and also though the contrast of both consequence, The safety of the construction process has been studied and analyzed. The result not only has important guiding meaning after the construction of the tunnel, but also provides the reference for the design and construction of similar projects
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