作者机构：
[Xiong, Pei-Ying] Hunan City Univ, Sch Sci, Yiyang 413000, Peoples R China.;[Jahanshahi, Hadi] Univ Manitoba, Dept Mech Engn, Winnipeg, MB R3T 5V6, Canada.;[Alcaraz, Raul] Univ Castilla La Mancha UCLM, Res Grp Elect Biomed & Telecommun Engn, Cuenca 16071, Spain.;[Chu, Yu-Ming] Huzhou Univ, Dept Math, Huzhou 313000, Peoples R China.;[Chu, Yu-Ming] Changsha Univ Sci & Technol, Hunan Prov Key Lab Math Modeling & Anal Engn, Changsha 410114, Peoples R China.
通讯机构：
[Yu-Ming Chu] D;[J.F. Gómez-Aguilar] C;CONACyT-Tecnológico Nacional de México/CENIDET. Interior Internado Palmira S/N, Col. Palmira, C.P. 62490, Cuernavaca, Morelos, México<&wdkj&>Universidad Tecnológica de México – UNITEC MÉXICO – Campus En Línea<&wdkj&>Department of Mathematics, Huzhou University, Huzhou 313000, P. R. China<&wdkj&>Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering, Changsha University of Science & Technology, Changsha 410114, P. R. China
关键词：
Chaos;Fractional calculus;Hidden attractors;Self-excited system;Robust control;Intelligent control technique;Disturbance observer
摘要：
An immense body of research has focused on chaotic systems, mainly because of their interesting applications in a wide variety of fields. A comprehensive understanding and synchronization of chaotic systems play pivotal roles in practical applications. To this end, the present study investigates a multi stable fractional-order chaotic system. Firstly, some dynamical features of the system are described, and the chaotic behaviour of the system is verified. Then, both spectral entropy and spectral Min-Entropy are computed, and the phenomenon of multi-stability is shown. Besides, the combination of a new chattering-free robust sliding mode controller with a neural network observer is proposed for the synchronization of the fractional-order system. With the neural network estimator, unknown functions of the system are obtained, and the effects of disturbances are completely taken into account. Also, based on the Lyapunov stability theorem, the asymptotical stability of the closed-loop system is confirmed. Lastly, the proposed control technique is applied to the fractional-order system. Numerical results demonstrate the chattering-free and effective performance of the proposed control method for uncertain systems in the presence of unknown time-varying external disturbances. (c) 2021 Elsevier Ltd. All rights reserved.
通讯机构：
[Yu-Liang Sun] S;[Dumitru Baleanu] D;School of Science, Huzhou University, Huzhou 313000, PR China<&wdkj&>Department of Mathematics, Faculty of Arts and Sciences, Cankaya University, Ankara, Turkey<&wdkj&>Institute of Space Sciences, Magurele, Romania<&wdkj&>Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
摘要：
The carbon nanotubes are among the most robust materials known to main (both in terms of tensile strength and vibrational properties). This strength is derived from the covalent bonds between carbon particles. In this research, carbon nanotubes in different sizes and chiralities and argon flow at supersonic velocity are simulated with molecular dynamics simulations, and their mechanical behavior is investigated. In this study, the stability of atomic structures, the effect of temperature and pressure on carbon nanotubes' vibrational behavior, and the effect of the velocity of argon atoms (ultrasonic flow) on the vibrational behavior of carbon nanotubes were investigated. Numerically, as the temperature and pressure of the simulated samples increase, the numerical value of the oscillation amplitude decreases to 2.12 angstrom and 2.30 angstrom, respectively. Also, with increasing temperature and pressure, these structures' frequency value rises to the numerical value of 13.02 ps(-1) and 12.59 ps(-1), respectively. (C) 2021 Elsevier B.V. All rights reserved.
作者：
Song, Ying-Qing;Khan, Sohail A.;Khan, M. Ijaz;Malik, M. Y.;Alqahtani, Ali S.
期刊：
Journal of Magnetics,2021年26(2):175-181 ISSN：1226-1750
作者机构：
[Song, Ying-Qing] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.;[Khan, Sohail A.] Quaid I Azam Univ, Dept Math, Islamabad 45320, Pakistan.;[Khan, M. Ijaz] Riphah Int Univ, Dept Math & Stat, I-14, Islamabad 44000, Pakistan.;[Alqahtani, Ali S.; Malik, M. Y.] King Khalid Univ, Coll Sci, Dept Math, Abha 61413, Saudi Arabia.
关键词：
darcy-forchheimer flow;curved stretching surface;heat source/sink;viscous dissipation;entropy generation and bejan number
摘要：
Here hydromagnetic flow of an incompressible Dary-Forchheimer fluid over a curved stretching surface is addressed. Heat source/sink and dissipation effects are considered in heat equation. Entropy generation is discussed through thermodynamics law. Bejan number is calculated. The proposed system are modeled in curvilinear coordinates. Partial differential system are reduced to ordinary one through transformation. ND-solve method is implemented to solve the given system. Graphical outcomes of velocity, entropy rate, temperature and Bejan number against flow variables are discussed. Numerical outcomes of drag force against pertinent variables are examined through table. Higher Hartman number decreases velocity field. A reverse effect for velocity is observed through porosity and curvature variables. An improvement in temperature is seen for curvature variable. An augmentation in entropy rate is noted for Brinkman number.
关键词：
ABSTRACT With the gradual improvement of people's quality of life, the average life expectancy of our country has been extended. It is estimated that the total number of the elderly population in China will exceed 250 million by the end of 2020. Therefore, promoting healthy aging is a necessary measure to cope with the coming aging society in China, and physical exercise is an important method to keep the physical and mental health of the elderly. In order to promote the development of healthy aging in China, this study focused on the current level of public sports services for the elderly. This study uses the expert consultation method to test the rationality of the evaluation index, and uses the method of questionnaire survey to score each evaluation index, and uses the analytic hierarchy process (AHP) to calculate the weight of the index. Finally, the paper takes the public sports service of the elderly in a city as an example to verify. The results show that the level of sports public service for the elderly in this city is only 77,928. Especially the two aspects of allocation of sports venues and the use of funds are the most unsatisfactory ones. It can be targeted to improve these two aspects, so as to improve the level of public sports services for the elderly. It is hoped that, through this study, we can provide some reference for improving the level of sports public service for the elderly from the perspective of healthy aging. Keywords: Elderly people;public service;sports;analytic hierarchy process;expert consultation method
摘要：
With the gradual improvement of people's quality of life, the average life expectancy of our country has been extended. It is estimated that the total number of the elderly population in China will exceed 250 million by the end of 2020. Therefore, promoting healthy aging is a necessary measure to cope with the coming aging society in China, and physical exercise is an important method to keep the physical and mental health of the elderly. In order to promote the development of healthy aging in China, this study focused on the current level of public sports services for the elderly. This study uses the expert consultation method to test the rationality of the evaluation index, and uses the method of questionnaire survey to score each evaluation index, and uses the analytic hierarchy process (AHP) to calculate the weight of the index. Finally, the paper takes the public sports service of the elderly in a city as an example to verify. The results show that the level of sports public service for the elderly in this city is only 77,928. Especially the two aspects of allocation of sports venues and the use of funds are the most unsatisfactory ones. It can be targeted to improve these two aspects, so as to improve the level of public sports services for the elderly. It is hoped that, through this study, we can provide some reference for improving the level of sports public service for the elderly from the perspective of healthy aging. Keywords: Elderly people; public service; sports; analytic hierarchy process; expert consultation method
期刊：
IET Image Processing,2021年15(1):155-165 ISSN：1751-9659
通讯作者：
Huang, Changjun
作者机构：
[Huang, Changjun; Zhou, Qingshan] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Huang, Changjun] Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.;[Zhou, Xinghua] Zhejiang Inst Hydraulice & Estuary, Hangzhou 310008, Peoples R China.;[Hu, Jiyuan] Wuhan Univ, Sch Geodesy & Geomat, Wuhan 430079, Peoples R China.
通讯机构：
[Huang, Changjun] H;Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.
关键词：
Optical, image and video signal processing;Radar equipment, systems and applications;Integral transforms;Principal component analysis
摘要：
In the process of synthetic aperture radar image noise suppression by the bi-dimensional empirical mode decomposition (BEMD) algorithm, the edge effect is a key problem in the BEMD operation. To weaken this effect, an improved BEMD-kernel principal component analysis (BEMD-KPCA) method of image denoising is proposed in this study. Experimental results show that the BEMDKPCA algorithm has a good capability of improving edge effects in the BEMD decomposition process and satisfying the requirement of the reliable decomposition results. Compared with the traditional BEMD method, the proposed approach has a good effect on suppressing speckle noise. Additionally, the denoised image from the decomposed components of the IMFs processed by the BEMD-KPCA method sufficiently preserves the edge and detail information, confirming its high coherency with the original image.
期刊：
Multimedia Tools and Applications,2021年80(15):22657-22670 ISSN：1380-7501
通讯作者：
Shu Xu
作者机构：
[Yuchi, Shu-yi] Liaoning Univ Technol, Coll Art Design & Architecture, Jinzhou 121000, Liaoning, Peoples R China.;[Xu, Shu] Hunan City Univ, Coll Informat & Elect Engn, Yiyang 413000, Hunan, Peoples R China.
通讯机构：
[Shu Xu] C;College of Information and Electronic Engineering, Hunan City University, Yiyang, Hunan, China
关键词：
Deep machine learning model;Multimedia;Visual image;Collaborative classification
摘要：
Aiming at the low accuracy of multimedia visual image cooperative classification, a new method of multimedia visual image cooperative classification based on depth machine learning model is proposed. Firstly, HSV color space model is selected to extract color features of multimedia visual images, Gabor function is used to extract texture features, and shape invariant moments are used to extract shape features. Then the features of multimedia visual images are recognized and classified, and the model parameters are optimized and adjusted according to the deviation of training output. The experimental results show that the average accuracy of this method is 95.892%, and the classification efficiency is high. The classification accuracy of this method is basically above 95%, and the classification accuracy is high. The training time of image type samples is 19 s, the testing time of image type is 12 s, and the time consumption is low.
摘要：
Electrically conductive cementitious composites (ECCCs) have become a significant research interest in structural health monitoring. The use of graphite in ECCCs can significantly improve their electrical performance, however, with unsatisfactory friction resistance because of the graphite's smooth microsurfaces. Slag can be incorporated with graphites into ECCCs to achieve good performance in both of mechanical resistance and electrical conductivity. This study investigated the impact of graphite and slag on the electrical and mechanical behaviors of ECCCs. Two hundred and eighty ECCC specimens were prepared with two different types of slags and with various conductivity ingredient fractions and curing times. The specimens were tested for compressive strength, flexural strength, and electrical resistance. It was concluded the 4% graphite content in ECCCs can significantly enhance electrical conductivity with moderate decrease in compressive and flexural strengths. Slags were found to improve both electrical conductivity and mechanical properties of ECCCs. The best results could be obtained with optimized contents of steel slag, blast furnace slag, and graphite. Finally, the microstructural mechanisms of the ECCC specimens were analyzed using scanning electron microscope (SEM) for graphite and slag. Variable sensitivity analysis was performed to allow for optimization of ingredient contents. (C) 2021 Elsevier Ltd. All rights reserved.
期刊：
Journal of International Medical Research,2021年49(2) ISSN：0300-0605
通讯作者：
Chen, Yuqing
作者机构：
[Chen, Yuqing; Li, Feng; Zhou, Xin; Zhang, Hai] Shanghai Jiao Tong Univ, Shanghai Chest Hosp, Dept Pulm & Crit Care Med, Shanghai, Peoples R China.;[Yuan, Yueyang] Hu Nan City Univ, Sch Mech & Elect Engn, Yi Yang, Peoples R China.;[Chen, Yuqing] Shanghai Jiao Tong Univ, Shanghai Chest Hosp, 241 Huahai West Rd, Shanghai 20030, Peoples R China.
通讯机构：
[Chen, Yuqing] S;Shanghai Jiao Tong Univ, Shanghai Chest Hosp, 241 Huahai West Rd, Shanghai 20030, Peoples R China.
关键词：
Dynamic respiratory mechanics;pressure support ventilation;pulmonary compliance;resistance;tidal volume;airway compliance;airway resistance
摘要：
Objective To evaluate the accuracy of respiratory mechanics using dynamic signal analysis during noninvasive pressure support ventilation (PSV). Methods A Respironics V60 ventilator was connected to an active lung simulator to model normal, restrictive, obstructive, and mixed obstructive and restrictive profiles. The PSV was adjusted to maintain tidal volumes (V-T) that achieved 5.0, 7.0, and 10.0 mL/kg body weight, and the positive end-expiration pressure (PEEP) was set to 5 cmH(2)O. Ventilator performance was evaluated by measuring the flow, airway pressure, and volume. The system compliance (C-rs) and airway resistance (inspiratory and expiratory resistance, R-insp and R-exp, respectively) were calculated. Results Under active breathing conditions, the C-rs was overestimated in the normal and restrictive models, and it decreased with an increasing pressure support (PS) level. The R-insp calculated error was approximately 10% at 10.0 mL/kg of V-T, and similar results were obtained for the calculated R-exp at 7.0 mL/kg of V-T. Conclusion Using dynamic signal analysis, appropriate tidal volume was beneficial for R-rs, especially for estimating R-exp during assisted ventilation. The C-rs measurement was also relatively accurate in obstructive conditions.
摘要：
In this study, reduced graphene oxide sheets (RGO) were previously modified by silane coupling when composited with Poly (phenylene sulfide) (PPS)/polyamide 6 (PA6) blends with a mass proportion of 4:6. Then the blends of RGO/PPS/PA6 were prepared under different mixing sequences, and it was found that the thermal conductivity of composite prepared by two-step blending showed enhanced values for immiscible blends compared with the one-step blending method at the same RGO loading. At the RGO loading of 4.06 wt%, the thermal conductivity of RGO/PPS/PA6 composite reached 0.74 W/(m center dot K) through the two-step blending method, which is 23.7% higher than that prepared by the one-step blending method. Moreover, great influences on the thermal conductivity and crystallization behavior of RGO were discussed. The thermal conductivity of RGO/PPS/PA6 composite with 36.36 wt% RGO reached 2.83 W/(m center dot K), which is 10.66 times higher than that of pure PPS/PA6 blend. Especially, based on DSC data, the introduction of PPS phase and RGO was proved to have little effect on the melting behavior of the composites, but a prominent heterogeneous nucleation effect and increased crystallization temperature were observed.
作者机构：
[Zhou, Shuang-Shuang] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.;[Shah, Nehad Ali] Sejong Univ, Dept Mech Engn, Seoul 05006, South Korea.;[Dassios, Ioannis] Univ Coll Dublin, AMPSAS, Dublin D04 V1W8, Ireland.;[Saleem, S.] King Khalid Univ, Coll Sci, Dept Math, Abha 61413, Saudi Arabia.;[Nonlaopon, Kamsing] Khon Kaen Univ, Fac Sci, Dept Math, Khon Kaen 40002, Thailand.
关键词：
Elzaki transform;homotopy perturbation method;variational iteration method;gas dynamic equations;Mittag-Leffler function
摘要：
This article introduces two well-known computational techniques for solving the time-fractional system of nonlinear equations of unsteady flow of a polytropic gas. The methods suggested are the modified forms of the variational iteration method and the homotopy perturbation method by the Elzaki transformation. Furthermore, an illustrative scheme is introduced to verify the accuracy of the available techniques. A graphical representation of the exact and derived results is presented to show the reliability of the suggested approaches. It is also shown that the findings of the current methodology are in close harmony with the exact solutions. The comparative solution analysis via graphs also represents the higher reliability and accuracy of the current techniques.
作者机构：
[Chen, Xinsheng; Geng, Mingming; Deng, Zhengmiao; Zou, Yeai; Li, Feng; Wang, Kelin; Xie, Yonghong] Chinese Acad Sci, Inst Subtrop Agr, Key Lab Agroecol Proc Subtrop Reg, Changsha 410125, Hunan, Peoples R China.;[Chen, Xinsheng; Geng, Mingming; Deng, Zhengmiao; Zou, Yeai; Li, Feng; Xie, Yonghong] Chinese Acad Sci, Inst Subtrop Agr, Dongting Lake Stn Wetland Ecosyst Res, Changsha 410125, Hunan, Peoples R China.;[Geng, Mingming] Univ Chinese Acad Sci, Beijing 100049, Peoples R China.;[Yang, Nan] Hunan City Univ, Coll Architecture & Urban Planning, Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Hunan, Peoples R China.;[Qian, Zhan] Hunan Hydro & Power Design Inst, Dongting Lake Res Ctr, Changsha 410007, Hunan, Peoples R China.
通讯机构：
[Feng Li] K;Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China<&wdkj&>Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, Hunan, China
摘要：
This work addresses several novel classes of convex function involving arbitrary non-negative function, which is known as approximately generalized (ψ,ℏ)-convex and approximately ψ-quasiconvex function, with respect to Raina’s function, which are elaborated in Hilbert space. To ensure the feasibility of the proposed concept and with the discussion of special cases, it is presented that these classes generate other classes of generalized (ψ,ℏ)-convex functions such as higher-order strongly (HOS) generalized (ψ,ℏ)-convex functions and HOS generalized ψ-quasiconvex function. The core of the proposed method is a newly developed Simpson’s type of identity in the settings of Riemann–Liouville fractional integral operator. Based on the HOS generalized (ψ,ℏ)-convex function representation, we established several theorems and related novel consequences. The presented results demonstrate better performance for HOS generalized ψ-quasiconvex functions where we can generate several other novel classes for convex functions that exist in the relative literature. Accordingly, the assortment in this study aims at presenting a direction in the related fields.
期刊：
Journal of Applied Polymer Science,2021年138(31):50750- ISSN：0021-8995
通讯作者：
Li, Duxin
作者机构：
[Lang, Feng; Song, Ling; Li, Duxin; Lin, Yi] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Song, Ling; Jiang, Qibin] Zhuzhou Times New Mat Technol Co Ltd, Zhuzhou, Peoples R China.;[You, Yilan] Hunan City Univ, Coll Mat & Chem Engn, Yiyang, Peoples R China.
通讯机构：
[Li, Duxin] C;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.
关键词：
copolymers;friction;polyamides;wear and lubrication
摘要：
A poly(phenylsulfone)-urea (PPSUU) macro-activator is synthesized by in situ anionic polymerization of 4,4 '-diaminodiphenylsulfone and hexamethylene diisocyanate. The PPSUU segment is embedded into the nylon molecular chain through copolymerization to improve the wear resistance and flame retardancy of monomer cast nylon 6 (MC PA6) materials. The mechanical properties, thermal stability, friction and wear properties and combustion heat release rate of copolymers with different macro-activator contents are tested. Results indicate that a small amount of PPSUU can improve the wear resistance and impact properties of nylon materials. The wear loss of MC nylon is 54.8% less than pure MC nylon from 1.049 x 10(-8) to 0.474 x 10(-8) g/Nm with 6 wt% PPSUU. Moreover, better flame retardancy is verified. The peak of HRR reduced 36.8% from 654 to 413 kw/m(2) with 4 wt% PPSUU, accompanied by advanced ignition time and flame extinction time, thus reducing the risk of fire.
摘要：
The effect of edge passivation with non-metallic atoms was evaluated on some structural and electronic properties of MoS2 nanoribbons. It was observed that at Na = 12 and above, the band gap is less oscillating and converges to 0.58 eV. By reducing the dimensionality, the band gap value changed dramatically. We found that d orbital of Mo atom greatly affects the density of states. All passivation processes were performed with H and X atoms, where X is a non-metallic atom. The hybridization of p and s orbitals of X and Mo atoms plays an important role in changing the electronic properties of AMoS2NR. It was found that after passivation the largest band gap change is related to the most stable structure. Our studies suggest that the band gap of AMoS2NR-H-X depends on two factors: the nanoribbon width and the hybridization of Mo-X orbitals.
作者机构：
[Zhang, Xiao-Hua; Wang, Deguo; Mu, Shu-Ting; Zheng, Jing-Jing; Zhou, San-Jiu] Xuchang Univ, Food & Pharm Coll, Henan Key Lab Biomarker Based Rapid Detect Techno, Xuchang 461000, Peoples R China.;[Qing, Xiang-Dong] Hunan City Univ, Coll Mat & Chem Engn, Hunan Prov Key Lab Dark Tea & Jin Hua, Yiyang 413049, Peoples R China.;[Kang, Chao] Guizhou Univ, Sch Chem & Chem Engn, Guiyang 550025, Peoples R China.;[Liu, Zhi] Hunan Univ Humanities Sci & Technol, Coll Agr & Biotechnol, Loudi 417000, Peoples R China.
通讯机构：
[Xiao-Hua Zhang] H;[Zhi Liu] C;Henan Key Laboratory of Biomarker Based Rapid-detection Technology for Food Safety, Food and Pharmacy College, Xuchang University, Xuchang, 461000, PR China<&wdkj&>College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Loudi, 417000, PR China
