1,229 research outputs found
A STUDY ON CORPUS-BASED EFL VOCABULARY TEACHING
This paper introduces the development of corpus linguistics and its advantages in EFL(English as Foreigner Language) vocabulary teaching from three aspects: theapplication of corpus into the vocabulary teaching can greatly improve the efficiencyfor vocabulary teaching by providing the word frequency. And by co-presenting theactual cases of different usages and contexts of the word, the corpus can help to avoidthe negative language transfer and thus enhance the learners’ comprehension andacquisition of the vocabulary
Anti-Washout Concrete: An overview
Anti-washout concrete (AWC) is a special cement-based material that can be directly employed in underwater environments without dispersion. It was developed around 50 years ago, and more than 150 journal articles and technical reports have been published. This paper provides a holistic review about the basic fresh-state and hardened-state properties of the AWC, such as water (washout) resistance, consistency, bleeding and segregation resistance, mechanical properties, and durability, as well as relevant testing methods. The discrepancies between AWC\u27s characteristics and those of conventional concrete are clearly presented. The mixture compositions, supplementary cementitious materials (SCMs), and other conditions that affect AWC\u27s performance are also elaborated. Finally, the paper discusses the specific performance requirements of AWC and corresponding construction strategies for its different applications, including normal construction, marine engineering, bulk filling, and repair practices. Future research needs to stimulate the development of AWC are also discussed
A New Two-Dimensional Functional Material with Desirable Bandgap and Ultrahigh Carrier Mobility
Two-dimensional (2D) semiconductors with direct and modest bandgap and
ultrahigh carrier mobility are highly desired functional materials for
nanoelectronic applications. Herein, we predict that monolayer CaP3 is a new 2D
functional material that possesses not only a direct bandgap of 1.15 eV (based
on HSE06 computation), and also a very high electron mobility up to 19930 cm2
V-1 s-1, comparable to that of monolayer phosphorene. More remarkably, contrary
to the bilayer phosphorene which possesses dramatically reduced carrier
mobility compared to its monolayer counterpart, CaP3 bilayer possesses even
higher electron mobility (22380 cm2 V-1 s-1) than its monolayer counterpart.
The bandgap of 2D CaP3 can be tuned over a wide range from 1.15 to 0.37 eV
(HSE06 values) through controlling the number of stacked CaP3 layers. Besides
novel electronic properties, 2D CaP3 also exhibits optical absorption over the
entire visible-light range. The combined novel electronic, charge mobility, and
optical properties render 2D CaP3 an exciting functional material for future
nanoelectronic and optoelectronic applications
Sulfuric Acid and Ammonia Generation by Bipolar Membranes Electrodialysis: Transport Rate Model for Ion and Water through Anion Exchange Membrane
Regeneration of sulfuric acid and ammonia from ammonium sulfate by bipolar membrane electrodialysis (BMED) coupling with stripping ammonia by air-blowing was studied. The result showed that it was feasible to regenerate sulfuric acid and ammonia from ammonium sulfate solution using this method. Empirical models to describe the ion and water transport behaviors through anion exchange membrane for BMED system were successfully developed. The models were valid to evaluate water transport rate and ion transport behavior for anion exchange membrane under similar operation conditions. Comparison of calculated values with experimental data indicated that the models were reliable to describe the water and ion transport behavior through anion exchange membrane for BMED system and also be used to predict the water transport and ion transport behaviors for other current density under similar operation condition
Decision Tables: Scalable Classification Exploring RDBMS Capabilities
In this paper, we report our success in building efficient scalable classifiers in the form of decision tables by exploring capabilities of modern relational database management systems. In addition to high classification accuracy, the unique features of the approach include its high training speed, linear scalability, and simplicity in implementation. More importantly, the major computation required in the approach can be implemented using standard functions provided by the modern relational DBMS. This not only makes implementation of the classifier extremely easy, further performance improvement is also expected when better processing strategies for those computations are developed and implemented in RDBMS. The novel classification approach based on grouping and counting and its implementation on top of RDBMS is described. The result
Design of Magnesium Phosphate Cement Based Composite for High Performance Bipolar Plate of Fuel Cells
In this work, we report a comprehensive study on a magnesium phosphate cement (MPC) based composite as the construction material for high performance bipolar plates of fuel cells. MPC with partial replacement of fly ash was employed as the binding matrix. Some carbon-based materials, such as graphite, carbon black, carbon fiber, and multi-walled carbon nanotubes were used to construct the conductive phase. A simple hot-press process was applied to produce the composite. The formula and the structure of the composite was modified and adjusted to optimize the properties of the composite to meet the US DOE 2015 technical targets, including the introducing of a reinforcement support. Finally, all the technical targets such as electrical conductivity (\u3e100 S cm-1), the flexural strength (\u3e25 MPa), the corrosion resistance ( \u3c 1 μA cm-2), and gas permeability ( \u3c 10-5 cm3 (s cm2)-1) were achieved as well as low cost ( \u3c 5 $ per kW). The optimized formula and the detailed procedures to fabricate the MPC based composite were concluded
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