12 research outputs found
Open-Vocabulary Argument Role Prediction for Event Extraction
The argument role in event extraction refers to the relation between an event
and an argument participating in it. Despite the great progress in event
extraction, existing studies still depend on roles pre-defined by domain
experts. These studies expose obvious weakness when extending to emerging event
types or new domains without available roles. Therefore, more attention and
effort needs to be devoted to automatically customizing argument roles. In this
paper, we define this essential but under-explored task: open-vocabulary
argument role prediction. The goal of this task is to infer a set of argument
roles for a given event type. We propose a novel unsupervised framework,
RolePred for this task. Specifically, we formulate the role prediction problem
as an in-filling task and construct prompts for a pre-trained language model to
generate candidate roles. By extracting and analyzing the candidate arguments,
the event-specific roles are further merged and selected. To standardize the
research of this task, we collect a new event extraction dataset from
WikiPpedia including 142 customized argument roles with rich semantics. On this
dataset, RolePred outperforms the existing methods by a large margin. Source
code and dataset are available on our GitHub repository:
https://github.com/yzjiao/RolePredComment: EMNLP 2022 Finding
Synthesis and White-Light Emission of ZnO/HfO2: Eu Nanocables
ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis
Hydrogen gas ppb-level detection based on AlGaN/GaN high electron mobility transistor with 2.0 nm thick Pt gate layer
Enhanced SERS Stability of R6G Molecules with Monolayer Graphene
In this work, we used monolayer graphene,
either underneath or on top of the R6G molecules, to enhance the stability
and reproducibility of surface enhanced Raman spectroscopy (SERS).
The time evolution of characteristic peaks of the organic molecules
was monitored using Raman spectroscopy under continuous light irradiation
to quantitatively characterize the photostability. Graphene underneath
the organic molecules inhibits the substrate-induced fluctuations;
and graphene on top of the organic molecules encapsulates and isolates
them from ambient oxygen, greatly enhancing the photostability. Our
results showed that the average lifespan of R6G molecules with graphene
encapsulation can be increased by about 6-fold under high laser power
density (3.67 × 10<sup>6</sup> W/cm<sup>2</sup>) and is less
dependent on the power density of light irradiation
The structural, optical and thermoelectric properties of single target sputtered Cu2ZnSn(S,Se)(4) thin film
International audienceCu2ZnSn(S,Se)(4) (CZTSSe) thin film was fabricated by radio frequency magnetron sputtering single CZTSSe target without post-selenization or sulfuration. The formation of kesterite-type CZTSSe films with a nearly stoichiometric composition after in-situ annealing at 673 K can be achieved. The valence of the elements in CZTSSe films are Cu(I), Zn(II), Sn(IV), S(-II) and Se(-II). Optical transmission and absorption spectroscopy measurement reveal high absorption and the energy band gap is about 1.44 eV. The CZTSSe thin film is of p-type conductivity and high Seebeck coefficient value is of 450 mu V/K
Mass Transport Mechanism of Cu Species at the Metal/Dielectric Interfaces with a Graphene Barrier
The interface between the metal and dielectric is an indispensable part in various electronic devices. The migration of metallic species into the dielectric can adversely affect the reliability of the insulating dielectric and can also form a functional solid-state electrolyte device. In this work, we insert graphene between Cu and SiO<sub>2</sub> as a barrier layer and investigate the mass transport mechanism of Cu species through the graphene barrier using density functional theory calculations, second-ion mass spectroscopy (SIMS), capacitance–voltage measurement, and cyclic voltammetry. Our theoretical calculations suggest that the major migration path for Cu species to penetrate through the multiple-layered graphene is the overlapped defects larger than 0.25 nm<sup>2</sup>. The depth-profile SIMS characterizations indicate that the “critical” thickness of the graphene barrier for completely blocking the Cu migration is 5 times smaller than that of the conventional TaN barrier. Capacitance–voltage and cyclic voltammetry measurement reveal that the electrochemical reactions at the Cu/SiO<sub>2</sub> interface become a rate-limiting factor during the bias-temperature stressing process with the use of a graphene barrier. These studies provide a distinct roadmap for designing controllable mass transport in solid-state electrolyte devices with the use of a graphene barrier