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399 results on '"Zhang, Xiao-Song"'

9. Achieving High Quantum Efficiency in Cs3Cu2I5 Nanocrystals by the A‑Site Ion Substitution for Flexible Blue Electroluminescence Devices and Enhanced Photovoltaic Cells.

Author

Yuan, Xiu-Rong, Zhang, Xiao-Song, Zhao, Xing-Yao, Gong, Xiao-Kai, Kong, Li−Na, Zhou, Bao-Zeng, Xu, Jian-Ping, and Li, Lan

Abstract

The outstanding photovoltaic characteristics of lead halide perovskites have made them a potential class of materials for upcoming optoelectronic applications. However, a major obstacle to the practical use of lead halide perovskites is the inherent toxicity and low environmental stability of lead. The exploration and development of nontoxic and stable alternatives for lead halide perovskites has therefore become an urgent and critical goal in the field of photovoltaics. In this paper, blue lead-free Cs3Cu2I5 nanocrystals (NCs) with bright emission were prepared by using KI as a metal additive through an improved thermal injection strategy. A breakthrough in the previous photoluminescence quantum (PLQY) yield of 97.2% was achieved when the content of KI was optimized to be 8%. Detailed experimental and theoretical studies have also been combined to conclude that the KI additive acts to passivate surface defects and that the broad-spectrum blue emission originates from self-trapped excitons. When combined with commercial indium tin oxide (ITO), the device may achieve broad-spectrum blue electroluminescence. Its low production cost and simple structure are its main features. Furthermore, we were able to improve the utilization of high-energy ultraviolet energy and overcome the weak absorption of short-wavelength silicon-based solar cells by using nanocrystals as down-conversion luminescent materials in conjunction with silicon-based solar cells. This increased the photoelectric conversion efficiency (PCE) for the solar cells through approximately 0.5%. The result was achieved through the principle of down-conversion. Therefore, fully inorganic metal halide Cs3Cu2I5: K+ nanocrystals have great potential for future electroluminescence and photovoltaic applications. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Data and Behavior Analysis of Blockchain-based DApp

Author

HU Teng, WANG Yan-ping, ZHANG Xiao-song, NIU Wei-na

Subjects
blockchain, ethereum, dapp, data analysis, empirical study, Computer software, QA76.75-76.765, Technology (General), T1-995
Abstract

Blockchain technology has evolved rapidly in recent years,as a result,many organizations and enterprises have started using decentralized applications (DApps) based on blockchain and smart contracts to enhance the functionality and security of their information systems,or to expand new businesses.However,DApps may also introduce new problems due to the possible security and performance issues of blockchain and smart contracts.In order to deeply study and analyze the data and behavioral phenomena of DApps so as to help users better apply blockchain and DApps,a total of 2 565 DApps in 21 categories are first collected,as well as data related to these DApps from July 30,2015 to May 4,2020 (about 10 million block heights),including 16 302 smart contracts,7 678 185 EOA,95 889 930 external transactions,and 30 833 719 internal transactions.Then the DApp distribution is deeply analyzed from four perspectives:number,time,category,and smart contract,and some findings are summarized from them,which can provide valuable references for DApp developers and blockchain researchers.

Published
2021
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29. An AI Enhanced Strategy of Service Offloading for IoV in Mobile Edge Computing

Author

Peng Hong Yu, Zhang Xiao Song, Li Hong Wu, Xu Le Xi, and Wang Xiao Dong

Abstract

A full connected world is expected to gain in the 6th generation mobile network (6G). As a typi-cal fully connected scenario, the internet of vehicle (IoV) enables intelligent vehicle operations via artificial intelligence (AI) and edge computing technologies. In the future of vehicular net-works, wide variety of services need powerful computing resources and higher quality of ser-vice (QoS). Existing resources are insufficient to match these requirements. Aim to this problem, An intelligent service offloading framework is provided. Based on the framework, an Algorithm of Improved Gradient Descent (AIGD) is created to accelerate the speed of iteration. So, the con-vergence of convolutional neural network (CNN) based on AIGD is able to be accelerated too. Then, an Algorithm of convolutional long short-term memory (CN_LSTM) Based Traffic Predic-tion (ACLBTP) is designed to gain the predicted number of vehicles belonged to the edge node. At last, an Algorithm of Service Offloading Based on CN_LSTM (ASOBCL) is conducted to of-fload these services to the vehicles belonged to the edge node. In ASOBCL, sorting technique is adopted to speed up the offloading work. Simulation results demonstrate the fact that the pre-diction strategy designed in this paper has high accuracy. The low offloading time and main-taining stable load balance is gained via running ASOBCL. Low offloading time means short response time. And, the QoS is guaranteed. So, these strategies designed in this paper are effec-tive and valuable.

Published
2023

30. Conpy: Concolic Execution Engine for Python Applications

Author

Chen, Ting, Zhang, Xiao-song, Chen, Rui-dong, Yang, Bo, Bai, Yang, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Kobsa, Alfred, Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Sun, Xian-he, editor, Qu, Wenyu, editor, Stojmenovic, Ivan, editor, Zhou, Wanlei, editor, Li, Zhiyang, editor, Guo, Hua, editor, Min, Geyong, editor, Yang, Tingting, editor, Wu, Yulei, editor, and Liu, Lei, editor

Published
2014
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