作者机构：
[Linbin Teng; Xiaodong Xu; Chunhua Yang; Biao Luo] School of Automation, Central South University, Changsha, 410083, Hunan, China;[Yuan Yuan] School of Electrical & Information Engineering, Changsha University of Science and Technology, Changsha, 410114, Hunan, China;[Stevan Dubljevic] Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 2R3, Alberta, Canada;[Tingwen Huang] Department of Sciences, Texas A&M University at Qatar, Edmonton, Doha 23874, Qatar
通讯机构：
[Xiaodong Xu] S;School of Automation, Central South University, Changsha, 410083, Hunan, China
摘要：
This paper proposes a novel concurrent learning-based adaptive boundary observer designed to tackle the joint estimation problem of system states and unknown parameters for a class of hyperbolic partial differential equation systems under the circumstance of unsatisfied persistent excitation conditions. By leveraging concurrent learning technique, an adapted data points selection algorithm is employed concurrently with current data to construct the adaptation law of unknown parameters, which overcomes the limitations imposed by persistent excitation conditions and ensures exponential convergence of estimation errors of unknown parameters under finite excitation conditions. Furthermore, combining the ideas of backstepping and swapping filters on the basis of uncertain estimation, a concurrent learning-based adaptive boundary observer is designed, accompanied by rigorous theoretical analysis and proofs to demonstrate its capability of achieving exponential convergence in estimation. Finally, the corresponding illustrative simulations are given to show the effectiveness of the proposed methodology.
摘要：
Here, an adaptive de‐morphing factor framework (ADFF) is proposed to restore the accomplice's facial image. A pioneering de‐morphing factor prediction network is proposed, which can better handle the variations in the degree of morphing across different images, to improve the quality of restored accomplice's facial images. Abstract Morphing attacks (MAs) pose a substantial security threat to the Automatic Border Control (ABC) system. While a few morphing attack detection (MAD) methods have been proposed, the face morphing accomplice's facial restoration has not received sufficient attention. Due to the inability to foresee the morphing factor used for a particular morphed image, selecting the appropriate de‐morphing factor becomes a challenging problem in the restoration of the accomplice's facial image. If the morphing factor cannot be chosen reasonably, achieving the desired restoration effect is difficult. Therefore, this paper presents an adaptive de‐morphing factor framework (ADFF) architecture for restoring the accomplice's facial image. By exploiting the morphed images stored in the electronic passport system and the real‐time captured criminal's images, ADFF can effectively restore the accomplice's facial image. Experimental results and analysis show that ADFF can significantly reduce the security threats of MAs on ABC.
摘要：
Polycyclic aromatic hydrocarbons (PAHs), a group of seriously hazardous environmental contaminants, have attracted extensive attention due to their carcinogenicity, genotoxicity, mutagenicity, and ubiquity. In this work, the excellent hydrophobic trifluoromethyl-enriched covalent organic framework (CF(3)-COF) was designed and synthesized as coating of solid-phase microextraction (SPME). The CF(3)-COF offered a high adsorption selectivity for PAHs, which could be attributed to the multiple interactions between the CF(3)-COF and PAHs, including hydrophobicity interaction, π-π and H bond interactions. Furthermore, headspace (HS) and direct immersion (DI) dual-mode solid-phase microextraction (HS/DI-SPME) were innovatively integrated as a dual-mode extraction by varying the length of SPME coating on stainless-steel, which could simultaneously and efficiently extract 16 PAHs with different volatile. Amazingly, the proposed strategy achieved fast adsorption for PAHs and shortened the adsorption equilibrium time to 15min. By further integrating with gas chromatography tandem mass spectrometry (GC-MS/MS), PAHs could be detected in the range of 0.008-0.16ngmL(-1) with a quantitative limit of 0.029-0.47ngmL(-1), respectively. The recoveries of PAHs in water samples ranged from 80.84 to 117.67%. This work indicates that the dual-mode CF(3)-COF-SPME is a promising candidate for the enrichment of multiple hazardous substances in complicated samples.
摘要：
Aesthetic expectations often constitute the primary focus in marketing nature-based tourist destinations. However, academic research has insufficiently explored the disparity between tourists' aesthetic expectations and the actual aesthetic quality maintenance in shaping satisfaction. Employing the Expectation Confirmation Theory, this study utilized structural equation modeling techniques to analyze survey data (n = 446). It proposed and tested an Aesthetic Expectation Confirmation Model to examine the relationship between aesthetic expectations, experiential qualities, and tourist satisfaction in the Zhangjiajie National Forest Park. The empirical findings show that aesthetic expectations have a direct, negative impact on satisfaction, while aesthetic expectation confirmation has a positive direct impact on satisfaction. Moreover, aesthetic expectation confirmation also plays a mediating role in the influence of aesthetic expectations and experiential quality on satisfaction. Specifically, aesthetic expectations indirectly impact satisfaction negatively through aesthetic expectation confirmation, whereas aesthetic experiential qualities have a positive, indirect impact on satisfaction through the same process. These findings offer theoretical contributions to the literature on forest recreation aesthetics and hold practical significance for the planning and management of destination aesthetics.
关键词：
Eco-driving;Offline reinforcement learning;Conservative Q-learning;Signal phase and timing
摘要：
Eco-driving represents a promising avenue for mitigating energy consumption in road transportation. To enhance the applicability of learning-based eco-driving strategies, this study presents a novel framework that employs offline reinforcement learning in eco-driving control. This framework enables a vehicle agent to acquire eco-driving behavior by leveraging real-world human driving trajectories. Specifically, the human driving trajectories, along with the corresponding traffic signal timing scheme, obtained from empirical data, are utilized to construct a comprehensive Markov Decision Process (MDP) dataset for offline policy training. To accommodate learning from sub-optimal human-driving data, a Conservative Q-learning (CQL) algorithm is deployed. Subsequently, the proposed offline learning method is compared with alternative learning-based, model-based, and rule-based approaches, effectively illustrating the feasibility of offline learning and the efficacy of the CQL algorithm. Notably, the energy consumption is demonstrated to be improved by 67.3% compared to a behavioral car-following model, with only marginal compromise to travel efficiency. Furthermore, a sensitivity analysis is conducted, revealing the generalizability of the offline learning-based method across various simulation configurations and even diverse energy consumption models.
摘要：
安卓系统为浏览器分配资源时无法感知网页内容,会导致资源过度分配和电量不必要损失。同时,由于CPU可调节频率密度的增长,通过动态电压频率缩放(dynamic voltage and frequency scaling, D...展开更多 安卓系统为浏览器分配资源时无法感知网页内容,会导致资源过度分配和电量不必要损失。同时,由于CPU可调节频率密度的增长,通过动态电压频率缩放(dynamic voltage and frequency scaling, DVFS)技术实现能耗优化的难度也随之增大。另外在系统默认的调控策略下,忽视了图形处理器(graphics processing unit, GPU)对浏览器运行的作用。针对上述问题,提出一种协同调控CPU和GPU实现功耗优化的方法。首先根据网页加载时处理器运行特征利用逻辑回归对网页进行分类,对网页特征加权实现复杂度量化,根据类别与复杂度采用DVFS技术限制CPU频率的同时调节GPU频率。该方法被应用于谷歌Pixel2 XL上的Chromium浏览器,对排名前500的中文网站进行测试,平均节省了12%功耗的同时减少了5%网页加载时间。收起
期刊：
Journal of Applied Toxicology,2024年 ISSN：0260-437X
通讯作者：
Liu, Zhonghua;Wang, Y
作者机构：
[Shu, Yuanyuan; Liu, Zhonghua; Ning, Chao; Wang, Jiaxu; Li, Yaqi; Wang, Ying; Liang, Songping; Zhou, Yini] Hunan Normal Univ, Coll Life Sci, Natl & Local Joint Engn Lab Anim Peptide Drug Dev, Changsha 410006, Hunan, Peoples R China.;[Shu, Yuanyuan; Ning, Chao; Wang, Jiaxu; Liu, Zhonghua; Li, Yaqi; Wang, Ying; Liang, Songping; Zhou, Yini] Hunan Normal Univ, Inst Interdisciplinary Studies, Changsha, Peoples R China.;[Shu, Yuanyuan; Ning, Chao; Wang, Jiaxu; Liu, Zhonghua; Li, Yaqi; Wang, Ying; Liang, Songping; Zhou, Yini] Hunan Normal Univ, Furong Lab, Peptide & small Mol drug R&D platform, Changsha, Peoples R China.;[Tan, Yijun] Changsha Univ Sci & Technol, Sch Comp & Commun Engn, Changsha, Peoples R China.
通讯机构：
[Liu, ZH; Wang, Y ] H;Hunan Normal Univ, Coll Life Sci, Natl & Local Joint Engn Lab Anim Peptide Drug Dev, Changsha 410006, Hunan, Peoples R China.
摘要：
Machine learning (ML) has shown a great promise in predicting toxicity of small molecules. However, the availability of data for such predictions is often limited. Because of the unsatisfactory performance of models trained on a single toxicity endpoint, we collected toxic small molecules with multiple toxicity endpoints from previous study. The dataset comprises 27 toxic endpoints categorized into seven toxicity classes, namely, carcinogenicity and mutagenicity, acute oral toxicity, respiratory toxicity, irritation and corrosion, cardiotoxicity, CYP450, and endocrine disruption. In addition, a binary classification Common-Toxicity task was added based on the aforementioned dataset. To improve the performance of the models, we added marketed drugs as negative samples. This study presents a toxicity predictive model, ToxMPNN, based on the message passing neural network (MPNN) architecture, aiming to predict the toxicity of small molecules. The results demonstrate that ToxMPNN outperforms other models in capturing toxic features within the molecular structure, resulting in more precise predictions with the ROC_AUC testing score of 0.886 for the Toxicity_drug dataset. Furthermore, it was observed that adding marketed drugs as negative samples not only improves the predictive performance of the binary classification Common-Toxicity task but also enhances the stability of the model prediction. It shows that the graph-based deep learning (DL) algorithms in this study can be used as a trustworthy and effective tool to assess small molecule toxicity in the development of new drugs. Machine learning has shown great promise in predicting toxicity of small molecules. This study presents a toxicity predictive model, ToxMPNN, based on the message passing neural network architecture, aiming to predict the toxicity of small molecules. ToxMPNN gives precise predictions with the ROC_AUC testing score of 0.886 for the Toxicity_drug dataset, which contains 27 toxic endpoints in seven toxicity categories and a binary classification Common-Toxicity task, and can be used as an effective tool to predict the toxicity of small molecules.
期刊：
International Journal of Microstructure and Materials Properties,2024年17(1):32-48 ISSN：1741-8410
作者机构：
1. School of Design and Art, Changsha University of Science and Technology, Changsha, 410114, China;2. The 23rd Metallurgical Construction Group Co., Ltd. of Minmetals, Changsha, 410116, China
摘要：
To improve the mechanical properties of UV cured 3D printing materials after curing, this paper proposes a study on the mechanical properties of UV cured 3D nanofibre printing materials. The THBP modified nano TiO2 is prepared as a subsequent auxiliary material, epoxy acrylate (EA) as a prepolymer, dipropylene glycol diacrylate (DPGDA) as a monomer, and phenyl bis (lithium phenyl-2,4,6-trimethylbenzoylphosphinate) phosphine oxide as a photoinitiator. A UV curable 3D printing material was prepared by adding THBP modified nano TiO2 in different proportions, and analysing the mechanical properties of the materials prepared. THBP modified nano TiO2 with different proportions of self synthesised THBP was added in order to achieve the research of strengthening and toughening modification and to improve its mechanical properties. The experimental results show that when the content of TEBP-TiO2 is 5 wt%, the tensile strength and impact strength of the samples prepared after UV curing reach the maximum value of 51.3 MPa and 22.1 KJ/m2, respectively. With the gradual increase of the content of THBP-TiO2, the initial decomposition temperature and the maximum decomposition temperature of the materials increase. The residual mass of thermal decomposition is increased and the thermal stability is improved.
作者：
Zhao, Chengwei;Huang, Tuo;Gao, Xinglong;Li, Yahui;Lu, Li
期刊：
Materials,2024年17(5):1027- ISSN：1996-1944
通讯作者：
Tuo Huang
作者机构：
[Gao, Xinglong; Lu, Li; Li, Yahui] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China;Author to whom correspondence should be addressed.;[Zhao, Chengwei] Guangxi Transportation Science Engineering Construction Co., Ltd., Nanning 530007, China;[Huang, Tuo] School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
通讯机构：
[Tuo Huang] S;School of Traffic and Transportation Engineering, Changsha University of Science and Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Cement-stabilized macadam materials are widely utilized as semi-rigid base materials in road construction. However, conventional cement-stabilized macadam (CCSM) bases often develop shrinkage cracks during early construction and maintenance due to variations in humidity and temperature. Shrinkage cracks can subsequently result in reflective cracks in the asphalt pavement, significantly reducing the overall service life of the road. This study systematically evaluates the shrinkage and mechanical properties of large-size cement-stabilized macadam (LSCSM). Initially, the mix proportion for LSCSM is determined using the Bailey method. Subsequently, an experimental design based on the response surface method is implemented to comprehensively investigate various properties, including unconfined compressive strength, compressive rebound modulus, flexural strength, and the durability aspects of early drying shrinkage and temperature shrinkage through laboratory experiments. Further, the performance differences between CCSM and LSCSM are analyzed comparatively. The findings reveal that the compressive strength of LSCSM surpasses that of CCSM, albeit with comparatively lower compressive rebound modulus and flexural strength. LSCSM demonstrates a unique blend of characteristics, exhibiting traits of both semi-rigid and flexible materials. Furthermore, LSCSM exhibits favorable crack resistance properties, as evidenced by lower dry shrinkage strain, average dry and temperature shrinkage coefficient compared to CCSM. The proposed LSCSM in this study effectively reduces cement dosage and enhances the crack resistance performance of base materials.
作者：
Shiqi Zhang;Yongling Wu;Lean Zhou*;Naif Abdullah Al-Dhabi;Shiquan Sun;...
期刊：
Chemical Engineering Journal,2024年485:149942 ISSN：1385-8947
通讯作者：
Lean Zhou
作者机构：
[Shiqi Zhang; Yongling Wu; Lean Zhou; Shiquan Sun; Haipeng Wu; Fenglin Li] Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province/School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China;[Naif Abdullah Al-Dhabi] Department of Botany and Microbiology, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia;[Jingju Cai] College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China;[Tian Li] MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin 300350, China;[Wangwang Tang] College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, China
通讯机构：
[Lean Zhou] K;Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province/School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China
摘要：
Bacteria colonized on solid electrode developing electroactive biofilm (EAB) has been shown to promote the contaminants biodegradation. Regulating electrode potential can improve the stability of extracellular electron transfer (EET), but how the electrode potential regulating the extracellular polymer secretion and the tetracycline (TC) removal has not been fully studied. Here, EAB cultured at 0 V was used to study the degradation mechanism of TC at different electrode potentials. Results showed that −0.1 V was the optimized electrode potential for TC biodegradation compared with 0.1 V, 0 V and −0.3 V, which was 28 % higher than that without electric field. Stimulation of electric field can retain proper extracellular polymer (EPS) to relieve the poison of TC, while excessive extracellular polysaccharide (PS) at 0 V have hindered the contact between microorganisms and TC, thus limited electron transfer and reduced the TC biodegradation efficiency. Excessively negative potential (−0.3 V) will restrict the electron transfer which was not conducive to the biodegradation of organic pollutants. Microbial community analysis revealed that TC addition have refreshed the EAB structure, Dokdonella and Norank_f_Rikenellaceae replaced Geobacter as the dominant species in EAB to promote TC biodegradation. The variation of metabolic pathway was suggested that the up-regulation of pyruvate metabolism and ubiquinone synthesis at −0.1 V have promoted the TC removal. This study has provided theoretical support for the electrode potential regulating the extracellular polymer secretion and promoting the pollution bioremediation.
摘要：
High-temperature hazards of asphalt pavement and pollution from car exhaust are two major problems that need to be solved in road construction. In this paper, a multifunctional composite coating has been prepared from the perspective of reducing road temperature and car exhaust degradation. The principle of heat-reflecting coating is used to reduce the road surface temperature. At the same time, the TiO2 aqueous solution with photocatalytic degradation effect is added to the heat-reflective coating material to achieve the purpose of degrading automobile exhaust degradation, creating a new type of multifunctional coating that has both cooling and exhaust degradation effects. In addition, by changing the amount of carbon black, a multi-functional coating with the best coloring is selected, so that it has better functionality and has the most suitable shade for the road surface. Finally, the cooling effect and the exhaust gas reduction effect are examined through indoor and outdoor tests and the slip resistance of the coating is tested using the pendulum method. The results show that the functional coating group has a certain ability of cooling and exhaust gas degradation compared to the normal control group without coating. For the functional coating group with different carbon black content, the functional coating (G2) with 0.9% carbon black content has the strongest overall functionality. The cooling and exhaust gas reduction effects proved to be the best. The surface cooling rate is 5.4 degrees C, while the internal cooling rate is 4.3 degrees C. The cumulative degradation efficiency of CO and NO is found to be 27.77%, and 73.75%, respectively.
摘要：
Recycled rubber materials represent an environmentally sustainable option as asphalt modifiers. This research delves into the modification effects of Styrene Butadiene Rubber (SBR) asphalt at varying SBR content levels, employing a blend of molecular simulation techniques and laboratory experimentation. A comprehensive molecular model of SBR-modified asphalt is established, and molecular dynamics simulations are executed to scrutinize the thermodynamic attributes, dipole moments, mechanical characteristics, and adhesion properties inherent to SBR asphalt. The outcomes of this inquiry reveal that SBR exhibits notable compatibility with a majority of asphalt molecules, as evidenced by their dipole moments. The introduction of SBR into the asphalt matrix results in the adsorption of a substantial quantity of lightweight components, fostering the formation of a cross-linked network that bolsters the asphalt's resilience against external deformation forces. Furthermore, in terms of adhesion work, asphalt demonstrates heightened affinity with alkaline aggregates, and SBR serves to augment van der Waals interactions at the asphalt-aggregate interface, thereby amplifying interfacial bonding strength. However, when the content of SBR reaches 30%, some SBR molecules will be aggregated in the asphalt, which will lead to phase separation and affect the stability of the colloid. Therefore, it is recommended that the content of SBR should be limited to about 20% in practical engineering applications. In this work, the modification mechanism of SBR was analyzed at the molecular scale and verified experimentally, and the results provide a theoretical basis for the rational use of recycled SBR powder in asphalt applications.
作者机构：
[Meng, Ruizhi; Cui, Zhexin; Yun, Di] Xi An Jiao Tong Univ, Sch Nucl Sci & Technol, Xian 710049, Peoples R China.;[Cui, Zhexin; Lozano-Perez, Sergio] Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England.;[Liu, Junkai] Xidian Univ, Sch Adv Mat & Nanotechnol, Xian 710126, Peoples R China.;[Deng, Huiqiu; Liu, Guangdong; Deng, HQ] Hunan Univ, Sch Phys & Elect, Changsha 410082, Peoples R China.;[Liu, Xiaochun; Tang, Guogao] Changsha Univ Sci & technol, Inst Met, Coll Mat Sci & Engn, Changsha 410082, Peoples R China.
通讯机构：
[Yun, D ] X;[Deng, HQ ] H;Xi An Jiao Tong Univ, Sch Nucl Sci & Technol, Xian 710049, Peoples R China.;Hunan Univ, Sch Phys & Elect, Changsha 410082, Peoples R China.
关键词：
Zirconium alloy;High-temperature oxidation;Effect of tin;Nanovoids
摘要：
The oxidation behavior of zirconium alloy in high-temperature steam plays a dominant role in the operation of nuclear reactors under accident conditions. The present work investigated the effect of Sn on the oxidation behavior of zirconium alloys in high-temperature steam at 1000 degrees C. The results of scanning electron microscopy (SEM), metallographic microscopy and synchrotron X-ray diffraction (S-XRD) analyses show that there are three layers in the oxidized sample, including prior beta-Zr, alpha-Zr(O) and ZrO2. High resolution analyses conducted in these layers by transmission electron microscopy (TEM) show that Sn atoms segregate around the oxide-metal (O-M interface and Zr-Sn intermetallic precipitates only present in the oxide film. Clear atomic arrangements of Zr5Sn3 were obtained by TEM, resulting in accurate identification of the Zr-Sn intermetallic phase. Also, TEM energy dispersive spectroscopy (EDS) maps show that Zr-Sn particles invariably accompany the segregation or precipitation of Nb. However, no clear precipitation sequence was observed, which suggests that a co-precipitation mechanism of Sn and Nb is in operation. As oxidation proceeds, nanovoids next to the Zr-Sn intermetallic particles were observed accompanied by local areas deficient in oxygen, identified as ZrO. Combining the interdiffusion trend obtained by Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, a mechanism for the transformation from the Zr-Sn intermetallic precipitates to nanovoids was proposed. This proposed mechanism may shed new light into the role of Sn in the oxidation resistance of zirconium alloy under LOCA conditions.
期刊：
Journal of Alloys and Compounds,2024年970:172434 ISSN：0925-8388
通讯作者：
Zeng, G;Zhou, XJ
作者机构：
[Sun, Wei; Zeng, Guang; Yao, Yuan; Deng, Yangchao; Liu, Wenyuan] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.;[Zhan, Hongyi] Gen Motors Global Res & Dev, China Sci Lab, Shanghai 201206, Peoples R China.;[Zhou, Xiaojie; Zhou, XJ] Changsha Univ Sci & Technol, Hunan Prov Key Lab Intelligent Mfg Technol High Pe, Changsha 410114, Peoples R China.
通讯机构：
[Zeng, G ; Zhou, XJ ] C;Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Key Lab Intelligent Mfg Technol High Pe, Changsha 410114, Peoples R China.
关键词：
Mg-Sn based alloy;Dynamic recrystallization;Precipitation;Hot compression
摘要：
The intrinsic correlation between dynamic precipitation and Dynamic Recrystallization (DRX) in a rare earth (RE)-free engineering Mg-4Sn-3Al-1Zn (TAZ431, wt.%) magnesium alloy has been systematically investigated. Hot compression tests were performed on the TAZ431 alloy, in comparison to Mg-3Al-1Zn (AZ31, wt.%) as a reference alloy, with varying temperatures, strain rates, and strain levels (T = 300 -460 degrees C; epsilon = 0.001 -1 s-1; epsilon = 0 to-0.9). Correlative microstructural characterizations including Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Electron Backscatter Diffraction (EBSD), were employed to explore the behaviors of precipitation, DRX and intragranular deformation as subjected to hot compression. The results indicate a significant interaction between Mg2Sn dynamic precipitation and the formation of DRXed grains. The TAZ431 alloy with Sn alloying exhibits profuse precipitation and larger DRX fraction within the microstructure, resulting in the increase of modulus and hardness. Nucleation of DRXed grains in the TAZ431 alloy was stimulated by relatively large (over 1 micrometer) undissolved Mg2Sn intermetallic particles. Meanwhile, the precipitation of nano-sized Mg2Sn occurred within DRXed grains and was facilitated by DRX process, consequently hindering the further growth of DRXed grains. The findings here may have implications for alloy design and thermal-mechanical processing of magnesium alloy structural components.
摘要：
In this paper, a linearized numerical scheme of nonlinear variable-order fractional diffusion equation with time delay is constructed. We apply the L2-1(sigma) formula to discretize the temporal derivative and second-order central difference scheme to discretize the spatial derivative. The proposed method is unconditionally stable and convergent with O(tau(2)+h(2)), where tau and h are the time and space steps, respectively. Numerical experiment demonstrates the effectiveness and accuracy of the numerical scheme.
摘要：
It is believed that local activation is the origin of all complexities, and the locally active memristive synaptic neural network can generate complex chaotic dynamic behaviors, such as hyperchaotic, multi-scroll, multi-stability and hidden dynamical behaviors. However, there are few studies on the simultaneous occurrence of multiple complex dynamic behaviors in neural networks. No chaotic system of multi-scroll hyperchaotic hidden attractors based on neural network has been found yet. To solve the problem, in this paper, we propose a new locally active memristive Hopfield neural network (HNN) model based on a multi-segment function, which is affected by electromagnetic radiation and external current. The multi-scroll hyperchaotic hidden attractors are found in the memristive HNN for the first time. Theoretical analysis and numerical simulation results show that the memristive HNN model has no equilibrium point, and the number of multi-scroll attractors is controlled by the state equation parameters of the memristive synapse. In addition, the structures and number of scrolls are also affected by electromagnetic radiation and external current. At the same time, under the appropriate parameter conditions, by modifying the initial value of the system, the memristive HNN has a controllable number of coexisting attractors, showing extreme multi-stability. Finally, a memristive HNN analog circuit is designed. The hardware experiment results reproduce the multi-scroll dynamics phenomenon, which verifies the correctness of the theoretical analysis and numerical simulation.
