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science China Materials 2023年第3期66卷 974-981页

作者：胡敏敏代君陈丽红孟阿兰王磊李桂村谢海姣李镇江 School of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao 266042China College of Electromechanical Engineering Qingdao University of Science and TechnologyQingdao 266042China State Key Laboratory Base of Eco-chemical Engineering College of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042China Hangzhou Yanqu Information Technology Co. Ltd.Hangzhou 310003China

离子插层是提高Ti_(3)C_(2)TxMXene电化学性能的有效方法之一.然而,不同的插层离子对MXene的结构和电化学性能的影响是否相同这一问题尚不清楚.本文系统研究了Li+、Na+、K+、Cs+、Zn2+、Mg2+、SO_(4)2-和OH-等一系列离子插层后的MXene... 详细信息

离子插层是提高Ti_(3)C_(2)TxMXene电化学性能的有效方法之一.然而,不同的插层离子对MXene的结构和电化学性能的影响是否相同这一问题尚不清楚.本文系统研究了Li+、Na+、K+、Cs+、Zn2+、Mg2+、SO_(4)2-和OH-等一系列离子插层后的MXene的结构特征和电化学性能.研究结果表明,插层离子的半径、电荷数和化学特性对插层效果都会产生影响.在所研究的插层剂中,由离子半径最大的一价阳离子Cs+和具有强碱性的阴离子OH-组成的插层剂CsOH对MXene具有较好的插层效果.插层后的MXene层间距增大,层间容纳了大量游离水,Ti的价态升高,片层表面有利于氧化还原反应的含O官能团增多,这都大大促进了电解液离子H+的扩散与存储.由此制备的电极的质量比电容大幅度提高,为原始MXene电极的7倍多,而且经过20,000次充放电循环后电容保持率未发生下降.本文为具有高电容性能的MXene和MXene基复合电极的合理设计和制备提供了指导.

关键词：电容性能充放电循环质量比电容电化学性能氧化还原反应离子半径复合电极电荷数

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Evidence of aircraft activity impact on local air quality: A study in the context of uncommon airport operation

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Journal of Environmental sciences 2023年第3期125卷 603-615页

作者： Hao Xu Kai Xiao Jun Pan Qingyan Fu Xiaodong Wei Junrui Zhou Yamei Yu Xue Hu Huarui Ren Jinping Cheng Shitao Peng Ningning Hong Yin Ye Ning Su Zehui He Tao Hu School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Wuhan Environmental Protection Science Academy Wuhan 430015China Shanghai Environmental Monitoring Center Shanghai 200233China Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044China East China Air Traffic Management Bureau CAAC Shanghai 200335China China-UK Low Carbon College Shanghai 201306China Tianjin Research Institute for Water Transport Engineering Ministry of TransportTianjin 300456China

Wuhan Tianhe International Airport (WUH) was suspended to contain the spread of COVID-19,while Shanghai Hongqiao International Airport (SHA) saw a tremendousflight *** of a major international airport is extremely rare and thus represents a unique opportunity to straightforwardly observe the impact of airport emissions on local air *** this study,a series of statistical tools were applied to analyze the variations in air pollutant levels in the vicinity of WUH and *** results of bivariate polar plots show that airport SHA and WUH are a major source of nitrogen ***,NO_(2)and NO diminished by 55.8%,44.1%,76.9%,and 40.4%,33.3% and 59.4% during the COVID-19 lockdown compared to those in the same period of 2018 and 2019,under a reduction in aircraft activities by 58.6%and61.4%.The concentration of NO_(2),SO_(2)and PM_(2.5)decreased by 77.3%,8.2%,29.5%,right after the closure of airport WUH on 23 January *** average concentrations of NO,NO_(2)and NOxscatter plots at downwind of SHA after the lockdown were 78.0%,47.9%,57.4%and 62.3%,34.8%,41.8%lower than those during the same period in 2018 and ***,a significant increase in O_(3)levels by 50.0% and 25.9%at WUH and SHA was observed,*** results evidently show decreased nitrogen oxides concentrations in the airport vicinity due to reduced aircraft activities,while amplified O_(3)pollution due to a lower titration by NO under strong reduction in NOxemissions.

关键词： Aircraft emissions COVID-19 Nitrogen oxides Ozone Airport closure

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Research on elephant flow detection method based on information entropy and improved random forest

Research on elephant flow detection method based on informat...

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2022 International Conference on Algorithms, Microchips and Network Applications

作者： Hu, Xiaohong Miao, Xianghua Yuan, Meiyu Faculty of Information Engineering and Automation Kunming University of Science and Technology Kunming650500 China Yunnan Key Laboratory of Computer Technology Application Kunming University of Science and Technology Kunming650500 China

ISBN: (纸本)9781510653290

In the increasingly complex network environment, various attacks emerge one after another. Being able to accurately detect elephant flow and mouse flow plays an extremely important role in defending against large-scale network attacks. Aiming at some shortcomings of current methods for detecting elephant flow and mouse flow, this paper proposes a detection method based on information entropy and improved random forest. After preprocessing the data, first calculate the data feature score with information entropy, screen out the truly valuable features according to the score, then put them into the improved random forest classifier, and finally get the detection results. In this paper, the grid search algorithm is used to optimize the tree and depth of random forest tree, so that the detection results can be obtained quickly and accurately. Experiments show that due to the significant difference between the data characteristics of elephant flow and mouse flow, this method can effectively identify elephant flow and mouse flow. The accuracy rate is 97.93%, the precision rate is 99.99%, the recall rate is 97.91%, and the F1-score is 98.94%, which is improved compared with other algorithms. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Complex networks

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Colossal magnetoresistance and Fermi surface topology in the layered Zintl-phase compound YbAl2Si2

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Physical Review B 2024年第17期110卷 174408页

作者： Fang Tang Yang Chen Xunqing Yin Weiyao Zhao Lei Zhang Zhida Han Renkui Zheng Xiaoming Zhang Yong Fang Jiangsu Laboratory of Advanced Functional Materials School of Electronic and information Engineering Jiangsu Key Laboratory of Thin Films School of Physical Science and Technology School of Physics and Astronomy and Tsung-Dao Lee Institute Department of Materials Science and Engineering School of Materials Science and Engineering School of Physics and Materials Science

Considerable attention has been devoted to CaAl2Si2-type Zintl-phase compounds for their intriguing physical properties, particularly the complex interplay between band structures and magnetism. Herein we grow high-quality single crystals of nonmagnetic YbAl2Si2 and examine the physical properties, including resistivity, magnetoresistance, angular magnetoresistance, Hall resistivity, and band structures. This compound shows metallic properties and Fermi-liquid behaviors. Its resistivity under magnetic fields increases as per Kohler rule, with normalized magnetoresistance curves merging into one, ruling out potential metal-insulator-like transitions. Colossal magnetoresistance is observed at low temperatures. Hall resistivity analysis categorizes this compound as an uncompensated semimetal. Its angle dependence of the magnetoresistance and quantum oscillation frequencies demonstrate an anisotropy ratio of ∼1.26 for the Fermi surface. Theoretical calculations corroborate these findings, mapping Fermi surfaces with three hole pockets and an electron pocket. Considering both the experimental and theoretical results, the colossal and angle-dependent magnetoresistance may be ascribed to unequal carrier densities coupled with large differences in carrier mobilities and Fermi-surface anisotropy, respectively. These results imply YbAl2Si2 is a promising candidate to study the crucial effect of electronic properties on its charge transport.

关键词： Colossal magnetoresistance Fermi surface Magnetotransport Semimetals Single crystal materials Topological materials Density functional calculations Fermi liquid theory Resistivity measurements

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SMGC-SBERT: A Multi-Feature Fusion Chinese Short Text Similarity Computation Model Based on Optimised SBERT

SMGC-SBERT: A Multi-Feature Fusion Chinese Short Text Simila...

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2024 IEEE International Conference on systems, Man, and Cybernetics, SMC 2024

作者： Zhao, Shuo Gu, Qiliang Zhang, Jianqiang Song, Gongpeng Lu, Qin Key Laboratory of Computing Power Network and Information Security Ministry of Education Shandong Computer Science Center Jinan China Shandong Engineering Research Center of Big Data Applied Technology Faculty of Computer Science and Technology Jinan China Shandong Provincial Key Laboratory of Computer Networks Shandong Fundamental Research Center for Computer Science Jinan China Shandong Branch of China Mobile Communication Group Design Institute Co. Jinan China

ISBN: (纸本)9781665410205

Chinese short text similarity computation stands as a pivotal task within natural language processing, garnering significant attention. However, existing models grapple with limitations in handling intricate semantic relationships, such as the challenge of discerning subtle semantic nuances in text, inadequacies in effectively integrating diverse levels of semantic information, and the struggle to capture polysemous meanings accurately. In addressing these issues, this paper introduces an innovative Chinese short text similarity computation model, SMGC-SBERT. This model addresses shortcomings of the existing models by employing a multi-module fusion strategy, thereby enabling a more precise measurement of semantic similarity between texts. Primarily, the model incorporates SAT embedding to acquire phrase-level semantic information and leverages the MS-BERT model to encode text, improving the model's comprehension of textual polysemy and obtaining richer semantic representation. Then, the fusion of module features, including multi-branch convolutional networks and mix pooling, enables the extraction of textual features from varied levels, bolstering the model's representational capacity. Additionally, to further reduce overfitting risks while improving accuracy and other performance, a multi-layer feature adjustment network is utilized for short text similarity calculation. The final resultant experimental findings showcase the superiority of the SMGC-SBERT model over other neural network models, demonstrating significant advancements across both Chinese-SNLI and CCKS2018_Task3 Chinese short text datasets. © 2024 IEEE.

关键词： Semantics

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Leveraging User-Defined Identifiers for Counterfactual Data Generation in Source Code Vulnerability Detection

Leveraging User-Defined Identifiers for Counterfactual Data ...

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IEEE International Workshop on Source Code Analysis and Manipulation

作者： Hongyu Kuang Feng Yang Long Zhang Gaigai Tang Lin Yang Academy of Military Sciences National Key Laboratory of Science and Technology on Information System Security Systems Engineering Institute Beijing China

Software vulnerability detection is a critical aspect of ensuring the security and reliability of software systems. However, traditional vulnerability detection approaches often have limitations due to the scarcity and need for more diversity in labeled data. This research introduces a novel approach to overcome these challenges by utilizing user-defined identifiers in the source code to generate counterfactual training data. User-defined identffiers, such as variable and function names, contain essential information about the intentions and logic of the program. By perturbing these identifiers while maintaining the syntactic and semantic structure of the code, we create a diverse set of counterfactual examples that simulate potential vulnerabilities. When combined with existing labeled data, these counterfactual examples enrich the training process for vulnerability detection models. To evaluate the effectiveness of our approach, we conduct experiments on various datasets, achieving state-of-the-art performance on the VulDeePecker and Draper datasets. Our approach also outperforms models that utilize the same pre-trained language model in terms of accuracy.

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Visual Servo Stabilization of Nonholonomic Mobile Robot Based on Epipolar Geometry and 1D Trifocal Tensor

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Chinese Journal of Electronics 2023年第4期22卷 729-734页

作者： CAO Zhengcai YIN Longjie FU Yili ZHANG Jie College of Information Science and Technology Beijing University of Chemical Technology Beijing China The State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China

In this paper, a visual servo stabilization approach consisting in a dynamic switching control law for a nonholonomic mobile robot is presented, which applies the epipolar geometry and the 1D trifocal tensor to drive the robot to a desired configuration. The whole motion process is divided into three steps. Firstly, an epipole-based control law is designed to make the robot rotate in place until the camera points to the desired position. The 1D trifocal tensor is then used in the second translation step to reach the desired place. Finally, the desired configuration is reached through a pure rotation using the epipolar geometry. The stability of the proposed control system is proved based on linear system control theory and Lyapunov theory. Simulation results are given to illustrate the effectiveness of the proposed controller.

关键词： Geometry Linear systems Visualization Tensors Simulation Switches Control systems

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Towards Semi-Supervised Segmentation of Retinal Fundus Images via Self-Training 3

Towards Semi-Supervised Segmentation of Retinal Fundus Image...

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3rd International Conference on Pattern Recognition and Machine Learning, PRML 2022

作者： Deng, Jianzhi Zhang, Fengming Li, Shuiwang Bao, Jindi Guilin University of Technology Guangxi Key Laboratory of Embedded Technology and Intelligent System Guilin China Guilin University of Technology School of Information Science and Engineering Guilin China

ISBN: (数字)9781665499507

ISBN: (纸本)9781665499507

Glaucoma is an eye disease that may cause blindness by damaging the optic nerve. The optic cup-to-disc ratio is one of the most important criteria in the diagnosis of glaucoma. However, accurately partitioning a retinal fundus image into optic cup and optic disc regions is crucial to precisely estimating the cup-to-disc ratio automatically. With the emergence of Deep Neural Networks (DNN) and available large-scale manually labeled training data, generic image segmentation has made great progress in recent years. However, large-scale well-labeled medical images are usually expensive and difficult to obtain. To address this problem, in this paper we propose a semi-supervised learning method for retinal fundus image segmentation via self-training based on the MR-Net. The proposed approach uses a self-training semi-supervised learning framework to generate pseudo-labels for unlabeled images. To improve the accuracy of the pseudo-labels, a dense conditional random field is introduced to refine the generated pseudo-labels during the self-training process. Experimental results show that the proposed method remarkably achieves state-of-the-art performance on the RIGA benchmark using only 50% of the annotated data for training, well alleviating the shortage of annotated training data in retinal fundus image segmentation. © 2022 IEEE.

关键词： Image segmentation

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Research on Tdoa Localization Model Based on Particle Swarm Optimization and Quasi-Newton Method

Research on Tdoa Localization Model Based on Particle Swarm ...

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Artificial Intelligence, Networking and information technology (AINIT), International Seminar on

作者： Chunjia Yu Yuxuan Peng Mingyan Shao Jin Liu Jiaqi Ren School of System Engineering National University of Defense Technology Changsha China National Key Laboratory of Information Systems Engineering National University of Defense Technology Changsha China

ISBN: (数字)9798331522285

ISBN: (纸本)9798331522292

This paper focuses on the problem of satellite-based Time Difference of Arrival (TDOA) passive location estimation and proposes a solution method combining the Particle Swarm Optimization (PSO) algorithm and the Quasi-Newton method. By constructing a TDOA-based localization model, the study delves into resolving the nonlinear optimization issues inherent in passive location estimation. Addressing the challenge of determining the initial point for the Quasi-Newton method, this paper innovatively suggests using the PSO algorithm to find the initial point. This approach effectively mitigates the difficulties associated with initial point determination and the tendency to fall into local optima, as validated by experiments demonstrating its superior optimization capabilities compared to traditional algorithms. Furthermore, the paper analyzes the scenario of estimating target positions with four base stations and explores the application of intelligent algorithms in solving traditional nonlinear problems, providing new theoretical support and practical guidance for solving TDOA localization models.

关键词： Location awareness Seminars Analytical models Satellites Time difference of arrival Noise Organizations Robustness Particle swarm optimization Optimization

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Simulation Analysis of Electromagnetic Output Force of Linear Motor with Single Magnetic Steel or Dual Magnetic Steel 5

Simulation Analysis of Electromagnetic Output Force of Linea...

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5th World Conference on Mechanical engineering and Intelligent Manufacturing, WCMEIM 2022

作者： Zhou, Yu-Kun Qiu, Hai-Ling Nanjing Engineering Institute of Aircraft Systems Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration Jiangsu Nanjing China

ISBN: (纸本)9781665473699

Taking the dual magnetic steel force motor used in a certain type of direct drive valve as the research object, the corresponding single magnetic steel force motor is derived according to its structure. Due to the similar structure of the single magnetic steel force motor and the dual magnetic steel force motor, the Ansoft electromagnetic simulation software can be used under the same conditions of armature parameters, air gap width, number of coil turns, and parts materials, etc. By analyzing the difference between the output force of single magnetic and dual magnetic force motors, the characteristics of the electromagnetic output force of both are determined. © 2022 IEEE.

关键词： Linear motors

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