检索结果-内蒙古大学图书馆

arXiv 2021年

作者： Dung, Dinh Ngoc Phan, Anh D. Nguyen, Toan T. Lam, Vu D. Faculty of Materials Science and Engineering Phenikaa University Yen Nghia Ha Dong Ha Noi12116 Viet Nam Phenikaa Institute for Advanced Study Phenikaa University Yen Nghia Ha Dong Ha Noi12116 Viet Nam Key Laboratory for Multiscale Simulation of Complex Systems Faculty of Physics VNU University of Science Vietnam National University – Hanoi 334 Nguyen Trai Street Thanh Xuan District Hanoi10000 Viet Nam Graduate University of Science and Technology Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Hanoi Viet Nam

We propose a theoretical model to elucidate intermolecular electrostatic interactions between a virus and a substrate. Our model treats the virus as a homogeneous particle having surface charge and the polymer fiber of the respirator as a charged plane. Electric potentials surrounding the virus and fiber are influenced by the surface charge distribution of the virus. We use Poisson-Boltzmann equations to calculate electric potentials. Then, Derjaguin’s approximation and a linear superposition of the potential function are extended to determine the electrostatic force. In this work, we apply this model for coronavirus or SARS-CoV-2 case and numerical results quantitatively agree with prior simulation. We find that the influence of fiber’s potential on the surface charge of the virus is important and is considered in interaction calculations to obtain better accuracy. The electrostatic interaction significantly decays with increasing separation distance, and this curve becomes steeper when adding more salt. Although the interaction force increases with heating, one can observe the repulsive-attractive transition when the environment is acidic. Copyright © 2021, The Authors. All rights reserved.

关键词： Boltzmann equation

来源：评论

学校读者我要写书评

暂无评论

Height and attitude tracking control of an unmanned helicopter via a HDOB-backstepping composite control method

Height and attitude tracking control of an unmanned helicopt...

引用

2019 Jiangsu Annual Conference on Automation, JACA 2019

作者： Han, Ling Wang, Xiangyu Li, Shihua Liu, Jiyu School of Automation Southeast University Nanjing210096 China Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of Education China Aviation Key Laboratory of Science and Technology on Aircraft Control Facri Xian710065 China

This study studies the height and attitude tracking control problem of an unmanned helicopter system with disturbances. A composite controller based on the combination of harmonic disturbance observers and backstepping technique is proposed to achieve asymptotic tracking for height and attitude. Firstly, harmonic disturbance observers (HDOB) are designed to estimate the unknown disturbances affecting each channel. Then, a composite controller is proposed by integrating the backstepping control technique and the HDOB technique together to achieve the height and attitude tracking goal. Stability analysis of the closed-loop system is given. Finally, numerical simulations are presented to verify the efficiency of the proposed control scheme. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Backstepping

来源：评论

学校读者我要写书评

暂无评论

Broadband Polarization-Conversion Metasurface for a Cassegrain Antenna with High Polarization Purity

引用

Physical Review Applied 2019年第1期12卷 014009-014009页

作者： Wen-Long Guo Guang-Ming Wang Ke Chen Hai-Peng Li Ya-Qiang Zhuang He-Xiu Xu Yijun Feng Air and Missile Defense College Air Force Engineering University Xi’an 710051 China Department of Electronic Engineering School of Electronic Science and Engineering Nanjing University Nanjing 210093 China Science and Technology on Complex Aviation Systems Simulation Laboratory Beijing 100076 China

Polarization conversion has been widely explored in the study of metasurfaces in order to achieve broad operation bandwidths, but its application is still restricted to a few practical scenarios. We design a broadband cross-polarization conversion metasurface and apply it to form a directionally radiated Cassegrain antenna with a low profile and high polarization purity. A quasi-I-shaped meta-atom is first optimized with both high cross-polarization conversion efficiency and a full span of phase modulation in a broad bandwidth. With a hyperbolic phase profile imposed on the surface, a metasurface is engineered that can conduct both focusing and polarization conversion into its cross-polarization component. Then, by introducing a polarized grating as a subreflector and simultaneously fixing the designed metasurface as the main reflector, a planar Cassegrain antenna is facilitated with a low profile, high gain, and high polarization purity in a broad frequency band. This strategy of broad-band polarization conversion and its attempt to design a Cassegrain antenna lays a foundation for high-performance functional devices, promising great potential in real-world applications.

关键词： Metamaterials Polarization of light Radio frequency techniques Devices Wireless communication networks Electromagnetic wave theory Microwave techniques

来源：评论

学校读者我要写书评

暂无评论

The Architecture of Digital System Model for systems-of-systems Engineering

The Architecture of Digital System Model for Systems-of-Syst...

引用

Chinese Automation Congress (CAC)

作者： Xinghai Gao Yaqi Zhang Zhuoqi Wang Institute of Unmanned System Beihang University Beijing China Science and Technology on Complex Systems Simulation Laboratory Beijing China

The rapid increasing challenges of modeling and simulation for systems-of-systems Engineering (SoSE) is to deal with their large-scale and complexity of heterogeneous and inter-dependent constituent systems. Typically, the method of structural modeling provides a thorough understanding of the composition and operation of different elements, but loses sight of the dynamic characteristics of the systems or components. To make a comprehensive analysis of the System-of-systems (SoS), the solution of behavior modeling will be more important to adapt to the evolving of the SoS, which focus on understanding the constituent systems and their relationships, and evaluating changes of the constituent system, and continuously responding to the new requirements and options of SoS. This paper discusses how to support the application of modeling and simulation (M&S) based on the framework of SysML to describe the architecture and capability of SoS, and combined with the process and activities of model-based system engineering (MBSE).

关键词： Unified modeling language Object oriented modeling Analytical models Digital systems Adaptation models

来源：评论

学校读者我要写书评

暂无评论

Interfacial strength vs toughness: Enhancing mechanical and impact performance of CF/PEEK thermoplastic composites

引用

Chemical Engineering Journal 2025年

作者： Yu Gao Song Yan Kaiyan Min Xiahui Liu Yue Li Ju Wu Jianfeng Zhou Shu Zhu Peng Wang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Shanghai Collaborative Innovation Center of High-Performance Fibers and Composites (Province-Ministry Joint) Key Laboratory of High-Performance Fibers & Products Ministry of Education Center for Civil Aviation Composites Donghua University Shanghai 201620 China Key Laboratory of Shanghai City for Lightweight Composites College of Materials Science and Engineering Donghua University Shanghai 201620 China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering Science BIC-ESAT College of Engineering Peking University Beijing 100871 China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules Shanghai Jiao Tong University Shanghai 201306 China Key Laboratory of Textile Science & Technology of Ministry of Education College of Textiles Donghua University Shanghai 201620 China

Carbon fiber reinforced thermoplastic composites (CFRTP) are highly recyclable, reducing waste and promoting sustainability in industrial applications. Good interfacial adhesion is key to the mechanical performance of CFRTPs. Despite its critical role in impact resistance and durability, interfacial toughness has received less attention than interfacial strength, which has been more widely studied and discussed. In this study, Carbon fiber fabrics were treated with two modifiers of different stiffness: polyimide (M1) and poly(arylsulfone) (M2). Composites containing varying concentrations of these modifiers were then fabricated via compression molding. The influence of modifier stiffness on the mechanical properties and fracture toughness of the composites was systematically analyzed. Compared to untreated fibers, the composites modified with an optimal concentration of M1 achieved tensile strength, flexural strength, and interlaminar shear strength (ILSS) improvements of 24.9 %, 20.5 %, and 27.8 %, respectively, while the M2 modified composites exhibited respective increases of 43.8 %, 19.3 %, and 28.3 %. Analysis of impact damage morphology and C-scan imaging revealed that composites modified with 2 wt% M1 and 1 wt% M2 exhibited reduced internal damage areas. The rigid -C=O-N structure of M1 led to brittle fracture, while the flexible long chains of M2 facilitated stress transfer and energy absorption, resulting in ductile fracture. Their compression-after-impact (CAI) failure modes were characterized by transverse cracking along the central defect. These findings provide valuable theoretical guidance for enhancing the toughness of thermoplastic composites through interfacial treatment.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Trend Prediction Method for Failures Time Series Data by Exploring Singular Spectrum Analysis and Support Vector Machines Regression

A Trend Prediction Method for Failures Time Series Data by E...

引用

作者： Wang Xin Liu Xingke Wu Jiantao Sang Yun Li Ying Wang Tingshu Science and Technology on Complex Aviation Systems Simulation Laboratory East China Institute of Computing Technology China Electronics Technology Group Corporation Unit 93658 of People's Liberation Army International School Beijing University of Posts and Telecommunications

Recently, reliability prediction problems have been sufficiently studied by applying various failures time series prediction models. However, these models' performance could easily reach the bottleneck on account of the noise interference of the failures data. This paper focuses on the trend component of failures time series data as we believe its noiseless curve will achieve better prediction results and help to provide scientific guidance for reliability activities. We propose a trend prediction method which mainly involves two steps, trend extraction by singular spectrum analysis(SSA) and noise test, and trend prediction by support vector machines regression(SVR). Moreover, we further develop a multi-layer grid search algorithm to obtain optimized parameters of SSA and SVR models. The performance of the proposed method is measured against other time series processing techniques such as seasonal-trend decomposition procedure based on loess(STL), Holt-Winters, autoregressive moving average(ARMA), multiple linear regression(MLR) and k-nearest neighbors(KNN). The comparison results indicate that the proposed method outperforms other techniques and can be utilized as a promising tool for failures time series trend prediction.

关键词： failures time series trend prediction singular spectrum analysis support vector machines regression grid search method

来源：评论

学校读者我要写书评

暂无评论

Query modeling for click data based image recognition using graph based propagation and sparse coding

Query modeling for click data based image recognition using ...

引用

9th International Conference on Internet Multimedia Computing and Service, ICIMCS 2017

作者： Wu, Weichen Tan, Min Zheng, Guangjian Yu, Jun Key Laboratory of Complex Systems Modeling and Simulation School of Computer Science and Technology Hangzhou Dianzi University Hangzhou310018 China

ISBN: (纸本)9789811085291

We address the fine-grained image recognition problem using user click data, wherein each image is represented as a semantical query-click feature vector. Usually, the query set obtained from search engines is large-scale and redundant. We propose a novel query modeling approach to merge semantically similar queries and construct a compact click feature. We represent each query as a click feature, and design a graph based propagation approach to predict the zero-clicks, ensuring similar images have similar clicks. Afterwards, using this feature, we formulate the problem as a sparse coding based recognition task, wherein the dictionary is discriminatively trained. We evaluate our method for fine-grained image recognition on the public Clickture-Dog dataset. It is shown that, the propagated click feature performs much better than the original one. Also, sparse coding performs better than K-means in query merging. © Springer Nature Singapore Pte Ltd. 2018.

关键词： Image recognition

来源：评论

学校读者我要写书评

暂无评论

The 2024 Motile Active Matter Roadmap

arXiv

引用

arXiv 2024年

作者： Gompper, Gerhard Stone, Howard A. Kurzthaler, Christina Saintillan, David Peruani, Fernado Fedosov, Dmitry A. Auth, Thorsten Cottin-Bizonne, Cecile Ybert, Christophe Clément, Eric Darnige, Thierry Lindner, Anke Goldstein, Raymond E. Liebchen, Benno Binysh, Jack Souslov, Anton Isa, Lucio di Leonardo, Roberto Frangipane, Giacomo Gu, Hongri Nelson, Bradley J. Brauns, Fridtjof Marchetti, M. Cristina Cichos, Frank Heuthe, Veit-Lorenz Bechinger, Clemens Korman, Amos Feinerman, Ofer Cavagna, Andrea Giardina, Irene Jeckel, Hannah Drescher, Knut Theoretical Physics of Living Matter Institute for Advanced Simulation Forschungszentrum Jülich Jülich Germany Princeton University Department of Mechanical and Aerospace Engineering PrincetonNJ United States Max Planck Institute for the Physics of Complex Systems Center for Systems Biology Dresden Cluster of Excellence Physics of Life TU Dresden Dresden Germany University of California San Diego United States CY Cergy Paris University France Université de Lyon Université Claude Bernard Lyon 1 CNRS Institut Lumière Matière Villeurbanne France Laboratoire PMMH-ESPCI UMR 7636 CNRS-PSL-Research University Sorbonne Université Université Paris Cité Paris France Institut Universitaire de France Paris France Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge United Kingdom Technische Universität Darmstadt Darmstadt64289 Germany Institute of Physics Universiteit van Amsterdam Science Park 904 Amsterdam1098 XH Netherlands T.C.M. Group Cavendish Laboratory University of Cambridge CambridgeCB3 0HE United Kingdom Laboratory for Soft Materials and Interfaces Department of Materials ETH Zurich Zurich8093 Switzerland Dipartimento di Fisica Sapienza Università di Roma Italy Department of Physics University of Konstanz Konstanz Germany Institute of Robotics and Intelligent Systems ETH Zürich Zurich Switzerland Kavli Institute for Theoretical Physics University of California Santa BarbaraCA93106 United States Department of Physics University of California Santa BarbaraCA93106 United States Molecular Nanophotonics Leipzig University Leipzig04013 Germany UMI FILOFOCS Israel Department of Physics of Complex Systems Weizmann Institute of Science Israel Rome Italy Dipartimento di Fisica Sapienza Università di Roma INFN Unità di Roma 1 Rome Italy Department of Biology and Biological Engineering California Institute of Technology Pasadena91125 United States Biozentrum University of Basel Basel4056 Switzerl

Activity and autonomous motion are fundamental aspects of many living and engineering systems. Here, the scale of biological agents covers a wide range, from nanomotors, cytoskeleton, and cells, to insects, fish, birds, and people. Inspired by biological active systems, various types of autonomous synthetic nano- and micromachines have been designed, which provide the basis for multifunctional, highly responsive, intelligent active materials. A major challenge for understanding and designing active matter is their inherent non-equilibrium nature due to persistent energy consumption, which invalidates equilibrium concepts such as free energy, detailed balance, and time-reversal symmetry. Furthermore, interactions in ensembles of active agents are often non-additive and non-reciprocal. An important aspect of biological agents is their ability to sense the environment, process this information, and adjust their motion accordingly. It is an important goal for the engineering of microrobotic systems to achieve similar functionality. With many fundamental properties of motile active matter now reasonably well understood and under control, the ground is prepared for the study of physical aspects and mechanisms of motion in complex environments, of the behavior of systems with new physical features like chirality, of the development of novel micromachines and microbots, of the emergent collective behavior and swarming of intelligent self-propelled particles, and of particular features of microbial systems. The vast complexity of phenomena and mechanisms involved in the self-organization and dynamics of motile active matter poses major challenges, which can only be addressed by a truly interdisciplinary effort involving scientists from biology, chemistry, ecology, engineering, mathematics, and physics. The 2024 motile active matter roadmap of Journal of Physics: Condensed Matter reviews the current state of the art of the field and provides guidance for further progress in t

关键词： Microrobots

来源：评论

学校读者我要写书评

暂无评论

Correction: Impact of ligand fields on Kubas interaction of open copper sites in MOFs with hydrogen molecules: an electronic structural insight

引用

RSC advances 2024年第44期14卷 32471页

作者： Trang Thuy Nguyen Hoan Van Tran Linh Hoang Nguyen Hoang Minh Nguyen Thang Bach Phan Toan Nguyen-The Yoshiyuki Kawazoe Faculty of Physics University of Science Vietnam National University Hanoi Vietnam nguyenthuytrang@hus.edu.vn. Key Laboratory for Multiscale Simulation of Complex Systems University of Science Vietnam National University Hanoi Vietnam. School of Engineering Physics Hanoi University of Science and Technology Hanoi Vietnam. Center for Innovative Materials and Architectures Vietnam National University Ho Chi Minh City Vietnam. Vietnam National University Ho Chi Minh City Vietnam. New Industry Creation Hatchery Center Tohoku University Sendai 980-8579 Japan. Department of Physics and Nanotechnology SRM Institute of Science and Technology Kattankulathur 603203 Tamilnadu India. School of Physics Institute of Science Suranaree University of Technology 111 University Avenue Nakhon Ratchasima 30000 Thailand.

[This corrects the article DOI: 10.1039/D4RA03946G.].

关键词：

来源：评论

学校读者我要写书评

暂无评论

Effect of temporal disorder on wave packet dynamics in one-dimensional kicked lattices

引用

Chinese Physics B 2018年第12期27卷 85-91页

作者： Yuting Wang Yi Gao Peiqing Tong Center for Quantum Transport and Thermal Energy Science School of Physics and TechnologyNanjing Normal UniversityNanjing 210023China jiangsu Key Laboratory on Opto-Electronic Technology School of Physics and TechnologyNanjing Normal UniversityNanjing 210023China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal UniversityNanjing 210023China

Inspired by the recent experimental progress in noisy kicked rotor systems,we investigate the effect of temporal disorder or quasi-periodicity in one-dimensional kicked lattices with pulsed on-site *** found that,unlike the spatial disorder or quasi-periodicity which usually leads to localization,the effect of the temporal one is more complex and depends on the spatial *** the kicked on-site potential is periodic in real space,then the wave packet will stay diffusive in the presence of temporal disorder or *** the other hand,if the kicked on-site potential is spatially quasi-periodic,then the temporal disorder or quasi-periodicity may lead to a shift of the transition point of the dynamical localization and destroy the dynamical localization in a certain parameter *** results we obtained can be readily tested by experiments and may help us better understand the dynamical localization.

关键词： temporal disorder quasi-periodicity dynamical localization

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：