3,753 research outputs found
Improved mechanical and electrical properties in electrospun polyimide/multiwalled carbon nanotubes nanofibrous composites
Highly aligned polyimide (PI) and PI/multi-walled carbon nanotubes (PI/MWCNTs) nanofibrous composites by incorporating poly(ethylene oxide) as the dispersing medium were fabricated using electrospinning technique. The morphology, mechanical, and electrical properties of the electrospun nanofibrous composites were investigated. Scanning electron microscope showed that the functionalized MWCNTs (f-MWCNTs) were well dispersed and oriented along the nanofiber axis. Analysis of electrical properties indicated a remarkable improvement on the alternating current conductivity by introduction of the aligned f-MWCNTs. Besides, with addition of 3 vol.% f-MWCNTs, the obvious enhancement of tensile modulus and strength was achieved. Thus, the electrospun PI/MWCNTs nanofibrous composites have great potential applications in multifunctional engineering materials
BBReach: Tight and Scalable Black-Box Reachability Analysis of Deep Reinforcement Learning Systems
Reachability analysis is a promising technique to automatically prove or
disprove the reliability and safety of AI-empowered software systems that are
developed by using Deep Reinforcement Learning (DRL). Existing approaches
suffer however from limited scalability and large overestimation as they must
over-approximate the complex and almost inexplicable system components, namely
deep neural networks (DNNs). In this paper we propose a novel, tight and
scalable reachability analysis approach for DRL systems. By training on
abstract states, our approach treats the embedded DNNs as black boxes to avoid
the over-approximation for neural networks in computing reachable sets. To
tackle the state explosion problem inherent to abstraction-based approaches, we
devise a novel adjacent interval aggregation algorithm which balances the
growth of abstract states and the overestimation caused by the abstraction. We
implement a tool, called BBReach, and assess it on an extensive benchmark of
control systems to demonstrate its tightness, scalability, and efficiency
1-Methyl-1H-indazole-3-carboxylic acid
The asymmetric unit of the title compound, C9H8N2O2, contains two molecules. In the crystal structure, both molecules form inversion dimers via pairs of O—H⋯O hydrogen bonds, and a C—H⋯O interation is also seen
Syntax-aware Neural Semantic Role Labeling
Semantic role labeling (SRL), also known as shallow semantic parsing, is an
important yet challenging task in NLP. Motivated by the close correlation
between syntactic and semantic structures, traditional discrete-feature-based
SRL approaches make heavy use of syntactic features. In contrast,
deep-neural-network-based approaches usually encode the input sentence as a
word sequence without considering the syntactic structures. In this work, we
investigate several previous approaches for encoding syntactic trees, and make
a thorough study on whether extra syntax-aware representations are beneficial
for neural SRL models. Experiments on the benchmark CoNLL-2005 dataset show
that syntax-aware SRL approaches can effectively improve performance over a
strong baseline with external word representations from ELMo. With the extra
syntax-aware representations, our approaches achieve new state-of-the-art 85.6
F1 (single model) and 86.6 F1 (ensemble) on the test data, outperforming the
corresponding strong baselines with ELMo by 0.8 and 1.0, respectively. Detailed
error analysis are conducted to gain more insights on the investigated
approaches.Comment: AAAI 201
Kerr-Sen Black Hole as Accelerator for Spinning Particles
It has been proved that arbitrarily high-energy collision between two
particles can occur near the horizon of an extremal Kerr black hole as long as
the energy and angular momentum of one particle satisfies a critical
relation, which is called the BSW mechanism. Previous researchers mainly
concentrate on geodesic motion of particles. In this paper, we will take
spinning particle which won't move along a timelike geodesic into our
consideration, hence, another parameter describing the particle's spin
angular momentum was introduced. By employing the Mathisson-Papapetrou-Dixon
equation describing the movement of spinning particle, we will explore whether
a Kerr-Sen black hole which is slightly different from Kerr black hole can be
used to accelerate a spinning particle to arbitrarily high energy. We found
that when one of the two colliding particles satisfies a critical relation
between the energy and the total angular momentum , or has a critical
spinning angular momentum , a divergence of the center-of-mass energy
will be obtained.Comment: Latex,17 pages,1 figure,minor revision,accepted by PR
Efficacy of omadacycline in the treatment of Legionella pneumonia: a case report
Legionella, one of the main pathogens that causes community-acquired pneumonia, can lead to Legionella pneumonia, a condition characterized predominantly by severe pneumonia. This disease, caused by the bacterium Legionella pneumophila, can quickly progress to critical pneumonia and is often associated with damage to multiple organs. As a result, it requires close attention in terms of clinical diagnosis and treatment. Omadacycline, a new type of tetracycline derivative belonging to the aminomethylcycline class of antibiotics, is a semi-synthetic compound derived from minocycline. Its key structural feature, the aminomethyl modification, allows omadacycline to overcome bacterial resistance and broadens its range of effectiveness against bacteria. Clinical studies have demonstrated that omadacycline is not metabolized in the body, and patients with hepatic and renal dysfunction do not need to adjust their dosage. This paper reports a case of successful treatment of Legionella pneumonia with omadacycline in a patient who initially did not respond to empirical treatment with moxifloxacin. The patient also experienced electrolyte disturbance, as well as dysfunction in the liver and kidneys, delirium, and other related psychiatric symptoms
2-[1-(4-Chlorobenzoyl)pyrrolidin-2-yl]-4,4,5,5-tetramethyl-4,5-dihydroimidazole-1-oxyl-3-oxide
In the title compound, C18H23ClN3O3, the imidazole ring system has an envelope conformation, whereas the nitronyl nitroxide unit displays a half-chair or twisted conformation. In the crystal, C—H⋯O hydrogen bonds build up a three-dimensional network
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