1,647 research outputs found
Earthquake Probability Assessment for the Indian Subcontinent Using Deep Learning.
Earthquake prediction is a popular topic among earth scientists; however, this task is challenging and exhibits uncertainty therefore, probability assessment is indispensable in the current period. During the last decades, the volume of seismic data has increased exponentially, adding scalability issues to probability assessment models. Several machine learning methods, such as deep learning, have been applied to large-scale images, video, and text processing; however, they have been rarely utilized in earthquake probability assessment. Therefore, the present research leveraged advances in deep learning techniques to generate scalable earthquake probability mapping. To achieve this objective, this research used a convolutional neural network (CNN). Nine indicators, namely, proximity to faults, fault density, lithology with an amplification factor value, slope angle, elevation, magnitude density, epicenter density, distance from the epicenter, and peak ground acceleration (PGA) density, served as inputs. Meanwhile, 0 and 1 were used as outputs corresponding to non-earthquake and earthquake parameters, respectively. The proposed classification model was tested at the country level on datasets gathered to update the probability map for the Indian subcontinent using statistical measures, such as overall accuracy (OA), F1 score, recall, and precision. The OA values of the model based on the training and testing datasets were 96% and 92%, respectively. The proposed model also achieved precision, recall, and F1 score values of 0.88, 0.99, and 0.93, respectively, for the positive (earthquake) class based on the testing dataset. The model predicted two classes and observed very-high (712,375 km2) and high probability (591,240.5 km2) areas consisting of 19.8% and 16.43% of the abovementioned zones, respectively. Results indicated that the proposed model is superior to the traditional methods for earthquake probability assessment in terms of accuracy. Aside from facilitating the prediction of the pixel values for probability assessment, the proposed model can also help urban-planners and disaster managers make appropriate decisions regarding future plans and earthquake management
Electric Field Enhanced Hydrogen Storage on BN Sheet
Using density functional theory we show that an applied electric field
substantially improves the hydrogen storage properties of a BN sheet by
polarizing the hydrogen molecules as well as the substrate. The adsorption
energy of a single H2 molecule in the presence of an electric field of 0.05
a.u. is 0.48 eV compared to 0.07 eV in its absence. When one layer of H2
molecules is adsorbed, the binding energy per H2 molecule increases from 0.03
eV in the field-free case to 0.14 eV/H2 in the presence of an electric field of
0.045 a.u. The corresponding gravimetric density of 7.5 wt % is consistent with
the 6 wt % system target set by DOE for 2010. Once the applied electric field
is removed, the stored H2 molecules can be easily released, thus making the
storage reversible.Comment: submitted to Phys. Rev. Lett. 15 pages with 6 figure
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Unusual spin pseudogap behavior in the spin web lattice Cu3TeO6 probed by 125Te nuclear magnetic resonance
We present a 125Te nuclear magnetic resonance (NMR) study in the three-dimensional spin web lattice Cu3TeO6 which harbors topological magnons. The 125Te NMR spectra and the Knight-shift K as a function of temperature show a drastic change at TS∼40K much lower than the Néel ordering temperature TN∼61K, providing evidence for the first-order structural phase transition within the magnetically ordered state. Most remarkably, the temperature dependence of the spin-lattice relaxation rate T−11 unravels spin-gap-like magnetic excitations, which sharply sets in at T∗∼75K, the temperature well above TN. The spin-gap behavior may be understood by weakly dispersive optical magnon branches of high-energy spin excitations originating from the unique corner-sharing Cu hexagon spin-1/2 network with low coordination number
Adsorption-controlled growth of La-doped BaSnO3 by molecular-beam epitaxy
Epitaxial La doped BaSnO3 films were grown in an adsorption controlled regime
by molecular beam epitaxy, where the excess volatile SnOx desorbs from the film
surface. A film grown on a (001) DyScO3 substrate exhibited a mobility of 183
cm^2 V^-1 s^-1 at room temperature and 400 cm^2 V^-1 s^-1 at 10 K, despite the
high concentration (1.2x10^11 cm^-2) of threading dislocations present. In
comparison to other reports, we observe a much lower concentration of (BaO)2
Ruddlesden Popper crystallographic shear faults. This suggests that in addition
to threading dislocations that other defects possibly (BaO)2 crystallographic
shear defects or point defects significantly reduce the electron mobility
Analysis of the Penn Korean Universal Dependency Treebank (PKT-UD): Manual Revision to Build Robust Parsing Model in Korean
In this paper, we first open on important issues regarding the Penn Korean
Universal Treebank (PKT-UD) and address these issues by revising the entire
corpus manually with the aim of producing cleaner UD annotations that are more
faithful to Korean grammar. For compatibility to the rest of UD corpora, we
follow the UDv2 guidelines, and extensively revise the part-of-speech tags and
the dependency relations to reflect morphological features and flexible
word-order aspects in Korean. The original and the revised versions of PKT-UD
are experimented with transformer-based parsing models using biaffine
attention. The parsing model trained on the revised corpus shows a significant
improvement of 3.0% in labeled attachment score over the model trained on the
previous corpus. Our error analysis demonstrates that this revision allows the
parsing model to learn relations more robustly, reducing several critical
errors that used to be made by the previous model.Comment: Accepted by The 16th International Conference on Parsing
Technologies, IWPT 202
A Fully Tunable Single-Walled Carbon Nanotube Diode
We demonstrate a fully tunable diode structure utilizing a fully suspended
single-walled carbon nanotube (SWNT). The diode's turn-on voltage under forward
bias can be continuously tuned up to 4.3 V by controlling gate voltages, which
is ~6 times the nanotube bandgap energy. Furthermore, the same device design
can be configured into a backward diode by tuning the band-to-band tunneling
current with gate voltages. A nanotube backward diode is demonstrated for the
first time with nonlinearity exceeding the ideal diode. These results suggest
that a tunable nanotube diode can be a unique building block for developing
next generation programmable nanoelectronic logic and integrated circuits.Comment: 14 pages, 4 figure
Electronic properties of CVD graphene: The role of grain boundaries, atmospheric doping, and encapsulation by ALD
Grain boundaries and unintentional doping can have profound
effects on graphene-based devices. Here we study these in
detail for CVD grown poly-crystalline monolayer graphene
with two significantly different grain size distributions
centered around 10–25 mm and 100–400 mm. Although the
two types of graphene are processed under identical
conditions after growth, they show distinct transport
properties in field effect transistor devices. While all asfabricated
samples showed similar p-type doping, the smaller
grain size type graphene with larger number of grain
boundaries exhibit lower average mobility. In order to
separate out the effects of grain boundaries and doping from
ambient exposure on the transport properties, the devices
were encapsulated with Al2O3 by atomic layer deposition.
The encapsulation of large grain samples thereby showed
drastic improvements in the performance with negligible
doping while the small grain samples are largely intolerant
to this process. We discuss the implications of our data
for the integrated manufacturing of graphene-based device
platforms.We acknowledge funding from
EPSRC (grant EP/K016636/1, GRAPHTED). Z.A.V.V. acknowledges
funding from ESPRC grant EP/L016087/1. J.A.A.-W.
acknowledges a Research Fellowship from Churchill College,
Cambridge.This is the final version of the article. It first appeared from Wiley at http://dx.doi.org/10.1002/pssb.201600255
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Adsorption-controlled growth of La-doped BaSnO3 by molecular-beam epitaxy
Epitaxial La-doped BaSnO3 films were grown in an adsorption-controlled regime by molecular-beam epitaxy, where the excess volatile SnOx desorbs from the film surface. A film grown on a (001) DyScO3 substrate exhibited a mobility of 183 cm2 V-1 s-1 at room temperature and 400 cm2 V-1 s-1 at 10 K despite the high concentration (1.2 × 1011 cm-2) of threading dislocations present. In comparison to other reports, we observe a much lower concentration of (BaO)2 Ruddlesden-Popper crystallographic shear faults. This suggests that in addition to threading dislocations, other defects - possibly (BaO)2 crystallographic shear defects or point defects - significantly reduce the electron mobility
Effect of a heat treatment on the precipitation behavior and tensile properties of alloy 690 steam generator tubes
The intergranular carbide precipitation behavior and its effect on the tensile properties were investigated in alloy 690. The precipitation of intergranular carbides, identified as Cr-rich M23C6, was retarded on the low-angle grain boundaries and the coincidence-site lattice boundaries. The M23C6 carbides have a cube-cube orientation relationship with the matrix. The ultimate tensile strength, yield strength, and elongation of the solution annealed alloy 690 are 648.2 ± 8.2 MPa, 242.8 ± 10.5 MPa and 44.9 ± 2.3%, respectively. The ultimate tensile strength and the yield strength increased to 764.8 ± 7.8 MPa and 364.8 ± 10.2 MPa until the aging time reached 16 h. This increase is ascribed to the M23C6 carbide acting as reinforcements. However, when the aging time exceed 16 h, these properties gradually decreased with increasing aging time. The decrease in ultimate tensile strength, yield strength, and elongation were mainly caused by the intergranular cracking due to the low bond strength between the carbide and the matrix
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