Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

To better utilize the sunlight for efficient solar energy conversion, the research on visible-light active photocatalysts has recently attracted a lot of interest. The photosensitization of transition metal oxides is a promising approach for achieving effective visible-light photocatalysis. This review article primarily discusses the recent progress in the realm of a variety of nanostructured photosensitizers such as quantum dots, plasmonic metal nanostructures, and carbon nanostructures for coupling with wide-bandgap transition metal oxides to design better visible-light active photocatalysts. The underlying mechanisms of the composite photocatalysts, e.g., the light-induced charge separation and the subsequent visible-light photocatalytic reaction processes in environmental remediation and solar fuel generation fields, are also introduced. A brief outlook on the nanostructure photosensitization is also given

NuSTAR observations of the young, energetic radio pulsar PSR B1509-58

We report on Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of the young rotation-powered radio pulsar PSR B1509$-$58 in the supernova remnant MSH 15$-$52. We confirm the previously reported curvature in the hard X-ray spectrum, showing that a log parabolic model provides a statistically superior fit to the spectrum compared with the standard power law. The log parabolic model describes the NuSTAR data, as well as previously published gamma-ray data obtained with COMPTEL and AGILE, all together spanning 3 keV through 500 MeV. Our spectral modelling allows us to constrain the peak of the broadband high energy spectrum to be at 2.6$\pm$0.8 MeV, an improvement of nearly an order of magnitude in precision over previous measurements. In addition, we calculate NuSTAR spectra in 26 pulse phase bins and confirm previously reported variations of photon indices with phase. Finally, we measure the pulsed fraction of PSR B1509$-$58 in the hard X-ray energy band for the first time. Using the energy resolved pulsed fraction results, we estimate that the pulsar's off-pulse emission has a photon index value between 1.26 and 1.96. Our results support a model in which the pulsar's lack of GeV emission is due to viewing geometry, with the X-rays originating from synchrotron emission from secondary pairs in the magnetosphere.Comment: 10 pages, 8 figures, 6 tables, ApJ accepte

Joint Extraction of Entities and Relations Using Reinforcement Learning and Deep Learning

We use both reinforcement learning and deep learning to simultaneously extract entities and relations from unstructured texts. For reinforcement learning, we model the task as a two-step decision process. Deep learning is used to automatically capture the most important information from unstructured texts, which represent the state in the decision process. By designing the reward function per step, our proposed method can pass the information of entity extraction to relation extraction and obtain feedback in order to extract entities and relations simultaneously. Firstly, we use bidirectional LSTM to model the context information, which realizes preliminary entity extraction. On the basis of the extraction results, attention based method can represent the sentences that include target entity pair to generate the initial state in the decision process. Then we use Tree-LSTM to represent relation mentions to generate the transition state in the decision process. Finally, we employ Q-Learning algorithm to get control policy π in the two-step decision process. Experiments on ACE2005 demonstrate that our method attains better performance than the state-of-the-art method and gets a 2.4% increase in recall-score

Pathwise solutions of SPDEs driven by Hölder-continuous integrators with exponent larger than 1/2 and random dynamical systems

This article is devoted to the existence and uniqueness of pathwise solutions to stochastic evolution equations, driven by a Hölder continuous function with Hölder exponent in (1/2, 1), and with nontrivial multiplicative noise. As a particular situation, we shall consider the case where the equation is driven by a fractional Brownian motion BH with Hurst parameter H > 1/2. In contrast to the article by Maslowski and Nualart, we present here an existence and uniqueness result in the space of H¨older continuous functions with values in a Hilbert space V. If the initial condition is in the latter space this forces us to consider solutions in a different space, which is a generalization of the H¨older continuous functions. That space of functions is appropriate to introduce a non-autonomous dynamical system generated by the corresponding solution to the equation. In fact, when choosing BH as the driving process, we shall prove that the dynamical system will turn out to be a random dynamical system, defined over the ergodic metric dynamical system generated by the infinite dimensional fractional Brownian motion.National Basic Research Program of ChinaNatural Science Foundation of Jiangsu ProvinceJiangsu Higher Education Committee of ChinaEuropean Funds for Regional DevelopmentMinisterio de Economía y Competitivida