4,329 research outputs found
HiPSEC x-ray diffraction and infrared spectroscopy studies on energetic materials under extreme conditions
We conducted a series of experiments on the decompositions of the energetic materials NaBH4, NH3BH3, HMX, and RDX under different pressures using the x-ray diffraction (XRD) technique; we also studied the lesser known but high-performance explosive FOX-7’s behaviors under high pressures using the infrared spectroscopy (IR) technique. For the chemical decomposition of NaBH4 and NH3BH3 we discovered possible x-ray induced hydrogen gas generation; for the decomposition of HMX and RDX, we discovered that the decay rates of these two materials vary with pressure respectively; for the study of FOX-7’s high pressure behaviors we discovered potential phase changes and pressure induced chemical reactions as pressure is increased
TensorLayer: A Versatile Library for Efficient Deep Learning Development
Deep learning has enabled major advances in the fields of computer vision,
natural language processing, and multimedia among many others. Developing a
deep learning system is arduous and complex, as it involves constructing neural
network architectures, managing training/trained models, tuning optimization
process, preprocessing and organizing data, etc. TensorLayer is a versatile
Python library that aims at helping researchers and engineers efficiently
develop deep learning systems. It offers rich abstractions for neural networks,
model and data management, and parallel workflow mechanism. While boosting
efficiency, TensorLayer maintains both performance and scalability. TensorLayer
was released in September 2016 on GitHub, and has helped people from academia
and industry develop real-world applications of deep learning.Comment: ACM Multimedia 201
Tight and attainable quantum speed limit for open systems
We develop an intuitive geometric picture of quantum states, define a
particular state distance, and derive a quantum speed limit (QSL) for open
systems. Our QSL is attainable because any initial state can be driven to a
final state by the particular dynamics along the geodesic. We present the
general condition for dynamics along the geodesic for our QSL. As evidence, we
consider the generalized amplitude damping dynamics and the dephasing dynamics
to demonstrate the attainability. In addition, we also compare our QSL with
others by strict analytic processes as well as numerical illustrations, and
show our QSL is tight in many cases. It indicates that our work is significant
in tightening the bound of evolution time
Diurnal modulation of electron recoils from DM-nucleon scattering through the Migdal effect
Halo dark matter (DM) particles could lose energy due to the scattering off
nuclei within the Earth before reaching the underground detectors of DM direct
detection experiments. This Earth shielding effect can result in diurnal
modulation of the DM-induced recoil event rates observed underground due to the
self-rotation of the Earth. For electron recoil signals from DM-electron
scatterings, the current experimental constraints are very stringent such that
the diurnal modulation cannot be observed for halo DM. We propose a novel type
of diurnal modulation effect: diurnal modulation in electron recoil signals
induced by DM-nucleon scattering via the Migdal effect. We set so far the most
stringent constraints on DM-nucleon scattering cross section via the Migdal
effect for sub-GeV DM using the S2-only data of PandaX-II and PandaX-4T with
improved simulations of the Earth shielding effect. Based on the updated
constraints, we show that the Migdal effect induced diurnal modulation of
electron events can still be significant in the low energy region, and can be
probed by experiments such as PandaX-4T in the near future
Family of attainable geometric quantum speed limits
We propose a quantum state distance and develop a family of geometrical
quantum speed limits (QSLs) for open and closed systems. The QSL time includes
an alternative function by which we derive three QSL times with particularly
chosen functions. It indicates that two QSL times are exactly the ones
presented in Ref. [1] and [2], respectively, and the third one can provide a
unified QSL time for both open and closed systems. The three QSL times are
attainable for any given initial state in the sense that there exists a
dynamics driving the initial state to evolve along the geodesic. We numerically
compare the tightness of the three QSL times, which typically promises a
tighter QSL time if optimizing the alternative function
CD: Fine-grained 3D Mesh Reconstruction with Twice Chamfer Distance
Monocular 3D reconstruction is to reconstruct the shape of object and its
other information from a single RGB image. In 3D reconstruction, polygon mesh,
with detailed surface information and low computational cost, is the most
prevalent expression form obtained from deep learning models. However, the
state-of-the-art schemes fail to directly generate well-structured meshes, and
most of meshes have two severe problems Vertices Clustering (VC) and Illegal
Twist (IT). By diving into the mesh deformation process, we pinpoint that the
inappropriate usage of Chamfer Distance (CD) loss is the root causes of VC and
IT problems in the training of deep learning model. In this paper, we initially
demonstrate these two problems induced by CD loss with visual examples and
quantitative analyses. Then, we propose a fine-grained reconstruction method
CD by employing Chamfer distance twice to perform a plausible and adaptive
deformation. Extensive experiments on two 3D datasets and comparisons with five
latest schemes demonstrate that our CD directly generates well-structured
meshes and outperforms others by alleviating VC and IT problems.Comment: under major review in TOM
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