1,946 research outputs found
Geological conditions and gas-bearing evaluation of the Niutitang Formation shale in the Xixiang–Zhenba area, China
Black carbonaceous shale of the Niutitang Formation in the Xixiang–Zhenba area was found to be well developed and abundant in high-quality shale gas. However, few studies have been conducted in this area, and its reservoir-forming conditions are not clear. This study aims to analyse source rocks, reservoir characteristics and storage conditions of the Niutitang Formation shale in the Xixiang–Zhenba area using field investigations, drilling and logging, supplemented with laboratory experiments. Results of this study shows that the Niutitang Formation shale is deeply buried at 1500–4500 m and is mainly 10-110 m thick. The shale is widely distributed, thicker in the west, thinner in the east and is a highly mature organic rich source rock with kerogen type I and II. The shale stratum features a high content of brittle minerals, many natural cracks, and a low content of clay minerals which are mainly illite, followed by a mixed layer of illite and smectite. The shale reservoir is characterized by low porosity and permeability. In addition, the lithology is dense and acts as a good seal in this area while it has a high adsorption capacity and high gas-bearing potential. Overall, within the study area, the western, central, and southern parts have good structural preservation conditions. The Niutitang Formation in the study area shows excellent organic matter characteristics for shale gas generation as well as good geological conditions for shale gas accumulation.</p
ReDirTrans: Latent-to-Latent Translation for Gaze and Head Redirection
Learning-based gaze estimation methods require large amounts of training data
with accurate gaze annotations. Facing such demanding requirements of gaze data
collection and annotation, several image synthesis methods were proposed, which
successfully redirected gaze directions precisely given the assigned
conditions. However, these methods focused on changing gaze directions of the
images that only include eyes or restricted ranges of faces with low resolution
(less than ) to largely reduce interference from other attributes
such as hairs, which limits application scenarios. To cope with this
limitation, we proposed a portable network, called ReDirTrans, achieving
latent-to-latent translation for redirecting gaze directions and head
orientations in an interpretable manner. ReDirTrans projects input latent
vectors into aimed-attribute embeddings only and redirects these embeddings
with assigned pitch and yaw values. Then both the initial and edited embeddings
are projected back (deprojected) to the initial latent space as residuals to
modify the input latent vectors by subtraction and addition, representing old
status removal and new status addition. The projection of aimed attributes only
and subtraction-addition operations for status replacement essentially mitigate
impacts on other attributes and the distribution of latent vectors. Thus, by
combining ReDirTrans with a pretrained fixed e4e-StyleGAN pair, we created
ReDirTrans-GAN, which enables accurately redirecting gaze in full-face images
with resolution while preserving other attributes such as
identity, expression, and hairstyle. Furthermore, we presented improvements for
the downstream learning-based gaze estimation task, using redirected samples as
dataset augmentation
Robustness of Half-Integer Quantized Hall Conductivity against Disorder in an Anisotropic Dirac Semimetal with Parity Anomaly
Two-dimensional Dirac semimetals with a single massless Dirac cone exhibit
the parity anomaly. Usually, such a kind of anomalous topological semimetallic
phase in real materials is unstable where any amount of disorder can drive it
into a diffusive metal and destroy the half-integer quantized Hall conductivity
as an indicator of parity anomaly. Here, based on low-energy effective model,
we propose an anisotropic Dirac semimetal which explicitly breaks time-reversal
symmetry and carries a half-integer quantized Hall conductivity. This
topological semimetallic phase can be realized on a deformed honeycomb lattice
subjected to a magnetic flux. Moreover, we perceptively investigate the
disorder correction to the Hall conductivity. The results show that the effects
of disorder can be strongly suppressed and thereby the nearly half-integer
quantization of Hall conductivity can exist in a wide region of disorder,
indicating that our proposed anisotropic Dirac semimetal is an exciting
platform to investigate the parity anomaly phenomena.Comment: 7 pages, 4 figure
The One-dimensional Chiral Anomaly and its Disorder Response
The condensed-matter realization of chiral anomaly has attracted tremendous
interest in exploring unexpected phenomena of quantum field theory. Here, we
show that one-dimensional (1D) chiral anomaly (i.e., 1D nonconservational
chiral current under a background electromagnetic field) can be realized in a
generalized Su-Schrieffer-Heeger model where a single gapless Dirac cone
occurs. Based on the topological Thouless pump and anomalous dynamics of chiral
displacement, we elucidate that such a system possesses the half-integer
quantization of winding number. Moreover, we investigate the evolution of 1D
chiral anomaly with respect to two typical types of disorder, i.e., on-site
disorder and bond disorder. The results show that the on-site disorder tends to
smear the gapless Dirac cone. However, we propose a strategy to stabilize the
half-integer quantization, facilitating its experimental detection.
Furthermore, we demonstrate that the bond disorder causes a unique crossover
with disorder-enhanced topological charge pumping, driving the system into a
topological Anderson insulator phase
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