University of Electronic Science and Technology of China

About: University of Electronic Science and Technology of China is a education organization based out in Chengdu, China. It is known for research contribution in the topics: Computer science & Antenna (radio). The organization has 50594 authors who have published 58502 publications receiving 711188 citations. The organization is also known as: UESTC.

FAMCDM: A fusion approach of MCDM methods to rank multiclass classification algorithms

Abstract: Various methods and algorithms have been developed for multiclass classification problems in recent years. How to select an effective algorithm for a multiclass classification task is an important yet difficult issue. Since the multiclass algorithm selection normally involves more than one criterion, such as accuracy and computation time, the selection process can be modeled as a multiple criteria decision making (MCDM) problem. While the evaluations of algorithms provided by different MCDM methods are in agreement sometimes, there are situations where MCDM methods generate very different results. To resolve this disagreement and help decision makers pick the most suitable classifier(s), this paper proposes a fusion approach to produce a weighted compatible MCDM ranking of multiclass classification algorithms. Several multiclass datasets from different domains are used in the experimental study to test the proposed fusion approach. The results prove that MCDM methods are useful tools for evaluating multiclass classification algorithms and the fusion approach is capable of identifying a compromised solution when different MCDM methods generate conflicting rankings.

Ultrafast charge transfer in MoS 2 /WSe 2 p-n Heterojunction

Abstract: Atomically thin and sharp van der Waals heterojunction can be created by vertically stacking p-type monolayer tungsten diselenide (WSe2) onto n-type molybdenum disulfide (MoS2). Theory predicts that stacked MoS2 and WSe2 monolayer forms type II p–n junction, creating a built-in electric field across the interface which facilitates electron–hole separation and transfer. Gaining insights into the dynamics of charge transfer across van der Waals heterostructure is central to understanding light-photocurrent conversion at these ultrathin interfaces. Herein, we investigate the exciton dissociation and charge transfer in a MoS2/WSe2 van der Waals hetero-structure. Our results show that ultrafast electron transfer from WSe2 to MoS2 take place within 470 fs upon optical excitation with 99% charge transfer efficiency, leading to drastic photoluminescence quenching and decreased lifetime. Our findings suggest that van der Waals heterostructure may be useful as active components in ultrafast optoelectronic devices.

Atomic Interlamellar Ion Path in High Sulfur Content Lithium-Montmorillonite Host Enables High-Rate and Stable Lithium–Sulfur Battery

Abstract: Fast lithium ion transport with a high current density is critical for thick sulfur cathodes, stemming mainly from the difficulties in creating effective lithium ion pathways in high sulfur content electrodes. To develop a high-rate cathode for lithium-sulfur (Li-S) batteries, extenuation of the lithium ion diffusion barrier in thick electrodes is potentially straightforward. Here, a phyllosilicate material with a large interlamellar distance is demonstrated in high-rate cathodes as high sulfur loading. The interlayer space (≈1.396 nm) incorporated into a low lithium ion diffusion barrier (0.155 eV) significantly facilitates lithium ion diffusion within the entire sulfur cathode, and gives rise to remarkable nearly sulfur loading-independent cell performances. When combined with 80% sulfur contents, the electrodes achieve a high capacity of 865 mAh g-1 at 1 mA cm-2 and a retention of 345 mAh g-1 at a high discharging/charging rate of 15 mA cm-2 , with a sulfur loading up to 4 mg. This strategy represents a major advance in high-rate Li-S batteries via the construction of fast ions transfer paths toward real-life applications, and contributes to the research community for the fundamental mechanism study of loading-independent electrode systems.