8,046 research outputs found
Phase composition and transformations in magnetron-sputtered (Al,V)2O3 coatings
Coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited by
pulsed DC reactive sputter deposition on Si(100) at a temperature of 550
{\deg}C. XRD showed three different crystal structures depending on V-metal
fraction in the coating: {\alpha}-V2O3 rhombohedral structure for 100 at.% V, a
defect spinel structure for the intermediate region, 63 - 42 at.% V. At lower
V-content, 18 and 7 at.%, a gamma-alumina-like solid solution was observed,
shifted to larger d-spacing compared to pure {\gamma}-Al2O3. The microstructure
changes from large columnar faceted grains for {\alpha}-V2O3 to smaller
equiaxed grains when lowering the vanadium content toward pure {\gamma}-Al2O3.
Annealing in air resulted in formation of V2O5 crystals on the surface of the
coating after annealing to 500 {\deg}C for 42 at.% V and 700 {\deg}C for 18
at.% V metal fraction respectively. The highest thermal stability was shown for
pure {\gamma}-Al2O3-coating, which transformed to {\alpha}-Al2O3 after
annealing to 1100{\deg} C. Highest hardness was observed for the Al-rich
oxides, ~24 GPa. The latter decreased with increasing V-content, larger than 7
at.% V metal fraction. The measured hardness after annealing in air decreased
in conjunction with the onset of further oxidation of the coatings
The Radio Properties and Magnetic Field Configuration in the Crab-like Pulsar Wind Nebula G54.1+0.3
We present a multifrequency radio investigation of the Crab-like pulsar wind
nebula (PWN) G54.1+0.3 using the Very Large Array. The high resolution of the
observations reveals that G54.1+0.3 has a complex radio structure which
includes filamentary and loop-like structures that are magnetized, a diffuse
extent similar to the associated diffuse X-ray emission. But the radio and
X-ray structures in the central region differ strikingly, indicating that they
trace very different forms of particle injection from the pulsar and/or
particle acceleration in the nebula. No spectral index gradient is detected in
the radio emission across the PWN, whereas the X-ray emission softens outward
in the nebula. The extensive radio polarization allows us to image in detail
the intrinsic magnetic field, which is well-ordered and reveals that a number
of loop-like filaments are strongly magnetized. In addition, we determine that
there are both radial and toroidal components to the magnetic field structure
of the pulsar wind nebula. Strong mid-IR emission detected in Spitzer Space
Telescope data is closely correlated with the radio emission arising from the
southern edge of G54.1+0.3. In particular, the distributions of radio and X-ray
emission compared with the mid-IR emission suggest that the PWN may be
interacting with this interstellar cloud. This may be the first PWN where we
are directly detecting its interplay with an interstellar cloud that has
survived the impact of the supernova explosion associated with the pulsar's
progenitor.Comment: 35 pages, 19 figures, accepted for publication in the Astrophysical
Journa
Metastable anisotropy orientation of nematic quantum Hall fluids
We analyze the experimental observation of metastable anisotropy resistance
orientation at half filled quantum Hall fluids by means of a model of a quantum
nematic liquid in an explicit symmetry breaking potential. We interpret the
observed ``rotation'' of the anisotropy axis as a process of nucleation of
nematic domains and compute the nucleation rate within this model. By comparing
with experiment, we are able to predict the critical radius of nematic bubbles,
. Each domain contains about electrons.Comment: 10 pages, 8 figures, final version as will appear in PR
Deep Learning-Based Long Term Mortality Prediction in the National Lung Screening Trial
In this study, the long-term mortality in the National Lung Screening Trial (NLST) was investigated using a deep learning-based method. Binary classification of the non-lung-cancer mortality (i.e. cardiovascular and respiratory mortality) was performed using neural network models centered around a 3D-ResNet. The models were trained on a participant age, gender, and smoking history matched cohort. Utilising both the 3D CT scan and clinical information, the models can achieve an AUC of 0.73 which outperforms humans at cardiovascular mortality prediction. The corresponding F1 and Matthews Correlation Coefficient are 0.60 and 0.38 respectively. By interpreting the trained models with 3D saliency maps, we examined the features on the CT scans that correspond to the mortality signal. By extracting information from 3D CT volumes, we can highlight regions in the thorax region that contribute to mortality that might be overlooked by the clinicians. Therefore, this can help focus preventative interventions appropriately, particularly for under-recognised pathologies and thereby reducing patient morbidity
IEEE Access Special Section Editorial: Recent Advances on Hybrid Complex Networks: Analysis and Control
Complex networks typically involve multiple disciplines due to network dynamics and their statistical nature. When modeling practical networks, both impulsive effects and logical dynamics have recently attracted increasing attention. Hence, it is of interest and importance to consider hybrid complex networks with impulsive effects and logical dynamics. Relevant research is prevalent in cells, ecology, social systems, and communication engineering. In hybrid complex networks, numerous nodes are coupled through networks and their properties usually lead to complex dynamic behaviors, including discrete and continuous dynamics with finite values of time and state space. Generally, continuous and discrete sections of the systems are described by differential and difference equations, respectively. Logical networks are used to model the systems where time and state space take finite values. Although interesting results have been reported regarding hybrid complex networks, the analysis methods and relevant results could be further improved with respect to conservative impulsive delay inequalities and reproducibility of corresponding stability or synchronization criteria. Therefore, it is necessary to devise effective approaches to improve the analysis method and results dealing with hybrid complex networks
Spin Waves in Detwinned BaFeAs
Understanding magnetic interactions in the parent compounds of
high-temperature superconductors forms the basis for determining their role for
the mechanism of superconductivity. For parent compounds of iron pnictide
superconductors such as FeAs ( Ba, Ca, Sr), although spin
excitations have been mapped out throughout the entire Brillouin zone (BZ),
measurements were carried out on twinned samples and did not allow for a
conclusive determination of the spin dynamics. Here we use inelastic neutron
scattering to completely map out spin excitations of 100\% detwinned
BaFeAs. By comparing observed spectra with theoretical calculations, we
conclude that the spin excitations can be well described by an itinerant model
with important contributions from electronic correlations.Comment: 6 pages, 4 figures, with supplemental materia
A Thermodynamic and Kinetic Characterization of the Solvent Dependence of the Saddle-Crown Equilibrium of Cyclotriveratrylene (CTV) Oxime
The equilibration of the saddle conformer of cyclotriveratrylene (CTV) oxime to the corresponding crown conformer was followed by (1)H NMR in five separate solvents, and kinetic and thermodynamic parameters were determined from the NMR data. The oxime saddle conformers of 3 are favored in CDCl(3) (K(eq) = [saddle]/[crown] = 1.4), whereas the CTV oxime crown conformer 3a is favored in three more polar solvents studied (DMSO-d(6), acetonitrile-d(3), acetone-d(6)). Surprisingly, the CTV oxime crown conformer is also slightly favored in the nonpolar solvent 1,4-dioxane-d(8). These behaviors are discussed in terms of hydrogen bonding, entropy, and possible host-guest considerations. An X-ray crystal structure was obtained for CTV monoketone, and structures of the different conformers of CTV, CTV ketone, and CTV oxime were calculated with semiempirical AM1 methods for direct comparison of their ground-state energies
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