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In this paper, a nine-dimensional chaotic system is designed and applied to secure communication.

Firstly, the equilibrium characteristics, dissipativity, bifurcation diagram and Lyapunov exponent spectrum are used to analyze the relevant characteristics of the proposed nine-dimensional chaotic system. In the analysis of Lyapunov exponential spectrum, when changing the linear parameters, the system shows two states, hyperchaos and chaos. For secure communication, there is a large secret key space. Secondly, C0 complexity and SEcomplexity of the system are analyzed, which shows that the system has sequences closer to random sequences.

The proposed nine-dimensional system has a large key space and more complex dynamic characteristics

The results show that the proposed nine-dimensional hyperchaotic system has excellent encryption capabilities and can play an important role in the field of secure communication.

With the development of integrated circuit and communication technology, digital secure communication has become a research hotspot. This paper aims to design a five-dimensional fractional-order chaotic secure communication circuit with sliding mode synchronous based on microcontroller (MCU).

First, a five-dimensional fractional-order chaotic system for encryption is constructed. The approximate numerical solution of fractional-order chaotic system is calculated by Adomian decomposition method, and the phase diagram is obtained. Then, combined with the complexity and 0–1 test algorithm, the parameters of fractional-order chaotic system for encryption are selected. In addition, a sliding mode controller based on the new reaching law is constructed, and its stability is proved. The chaotic system can be synchronized in a short time by using sliding mode control synchronization.

The electronic circuit is implemented to verify the feasibility and effectiveness of the designed scheme.

It is feasible to realize fractional-order chaotic secure communication using MCU, and further reducing the synchronization error is the focus of future work.

This study aims to improve the complexity of chaotic systems and the security accuracy of information encrypted transmission. Applying five-dimensional memristive Hopfield neural network (5D-HNN) to secure communication will greatly improve the confidentiality of signal transmission and greatly enhance the anticracking ability of the system.

Chaos masking: Chaos masking is the process of superimposing a message signal directly into a chaotic signal and masking the signal using the randomness of the chaotic output. Synchronous coupling: The coupled synchronization method first replicates the drive system to get the response system, and then adds the appropriate coupling term between the drive The synchronization error and the coupling term of the system will eventually converge to zero with time. The synchronization error and coupling term of the system will eventually converge to zero over time.

A 5D memristive neural network is obtained based on the original four-dimensional memristive neural network through the feedback control method. The system has five equations and contains infinite balance points. Compared with other systems, the 5D-HNN has rich dynamic behaviors, and the most unique feature is that it has multistable characteristics. First, its dissipation property, equilibrium point stability, bifurcation graph and Lyapunov exponent spectrum are analyzed to verify its chaotic state, and the system characteristics are more complex. Different dynamic characteristics can be obtained by adjusting the parameter k.

A new 5D memristive HNN is proposed and used in the secure communication

Social mediametrics is a subfield of measurement in which the emphasis is placed on social media data. This paper analyzes the trends and patterns of paper comprehensively mentions on Twitter, with a particular focus on Twitter's mention behaviors. It uncovers the dissemination patterns and impact of academic literature on social media. The research has significant theoretical and practical implications.

This paper explores the fundamental attributes of Twitter mentions by means of analyzing 9,476 pieces of scholarly literature (5,097 from Nature and 4,379 from Science), 1,474,898 tweets and 451,567 user information collected from Altmetric.com database and Twitter API. The study uncovers assorted Twitter mention characteristics, mention behavior patterns and data accumulation patterns.

The findings illustrate that the top academic journals on Twitter have a wider range of coverage and display similar distribution patterns to other academic communication platforms. A large number of mentioners remain unidentified, and the distribution of follower counts among the mention users exhibits a significant Pareto effect, indicating a small group of highly influential users who generate numerous mentions. Furthermore, the proportion of sharing and exchange mentions positively correlates with the number of user followers, while the incidence of supportive mentions has a negative correlation. In terms of country-specific mention behavior, Thai scholars tend to utilize supportive mentions more frequently, whereas Korean scholars prefer sharing mentions over communicating mentions. The cumulative pattern of Twitter mentions suggests that these occur before official publication, with a half-life of 6.02 days and a considerable reduction in the number of mentions is observed on the seventh day after publication.

Conducting a multi-dimensional and systematic analysis of Twitter mentions of scholarly articles can aid in comprehending and utilizing social media communication patterns. This analysis can uncover literature's distribution patterns, dissemination effects and social significance in social media.

This study aims to answer the question of how incumbent firms cultivate dynamic capabilities through knowledge management so that they can efficiently adapt to the changing external environment.

This study adopts a case study approach and collects data through interviews and secondary public information on the lighting industry and two lighting firms in Lin'an, China. It qualitatively examines the challenges and strategic recommendations for incumbent firms in the context of discontinuous technological change from a knowledge management perspective.

Incumbent firms often face a variety of challenges when responding to discontinuous technological change. These challenges include identifying opportunities, overcoming path dependence and dealing with employee resistance to change. To overcome these difficulties, three strategies have been proposed to enhance the dynamic capabilities of incumbent firms through knowledge management: cross-border search helps firms improve their knowledge acquisition capabilities and better understand their environment to identify opportunities; building strategic leadership overcomes path dependence and improves knowledge integration capabilities; organizational learning deepens employees’ understanding of change and enhances organizational knowledge application capabilities.

Previous research attributes a firm's ability to cope with discontinuous technological change solely to its general resources, which weakens the importance of knowledge management in this context. This study emphasizes the importance of knowledge as a crucial strategic resource in developing the essential dynamic capabilities for incumbent firms to cope with discontinuous technological change.

This study provides an in-depth analysis of incumbent firms' coping strategies in the new context of discontinuous technological change and further promotes cross-disciplinary research.

This study provides an in-depth analysis of coping strategies in the new context of discontinuous technological change, furthermore theoretically advancing the interdisciplinary research of firm transformation and knowledge management. Meanwhile, it is crucial to identify the preconditions for cultivating dynamic capabilities, especially from a knowledge-based view, which enhances the depth of knowledge management research.

45 steel is a common material for the manufacture of various components such as shafts or gears. However, its poor surface properties often limit its applications. The purpose of this paper is to find a way to enhance the surface performance of 45 steel, which is expected to improve the wear resistance of 45 steel.

Double glow plasma surface metallurgy technique was used to prepare hafnium carbide (HfC) coatings on the surface of the 45 steel with two preparation process; one is to diffuse two elements together, while the other is to diffuse step by step. The scanning electronic microscopy and the X-ray diffraction were used to analyze the morphology and phase of the HfC coatings. And then the wear tests were carried out for this coating.

Coating diffused step by step shows better performance; it has a 15-µm alloyed layer which is uniform and dense and its hardness can reach up to 1326.5 Vickers-hardness (HV). While the coating fabricated by diffusing elements together owns a 10-µm alloyed layer and its hardness is 1204.1 HV. According to the wear test results, both coatings have a protective effect on the substrate and the coating prepared by step-by-step diffusion process has less wear volume, indicating that it possesses better friction reduction.

A new method which diffuses elements together was successfully used to prepare compound HfC coating, which can reduce the cost of coating preparation and improve the efficiency of coating preparation.

The purpose of this work is to controllably synthesize a carbon aerogel with programmable functionally graded performance via a simple and effective strategy.

This work uses polyvinyl alcohol (PVA) via the controllable sol-gel, lyophilization, and carbonization approach to achieve a programmable carbon aerogel. This design has the advantages of low raw material and preparation cost, simple and controllable synthetic process and low carbonization temperature.

The thermal stability and microstructure of PVA aerogel can be controlled by the crosslinking agent content within a certain range. The crosslinking agent content and the carbonization temperature are the key factors for functionally graded programming of carbon aerogels, including microstructure, oxygen-containing functional groups and adsorption performance. The adsorption ratio and adsorption rate of uranium can be controlled by adjusting initial concentration and pH value of the uranium solution. The 2.5%25 carbon aerogel with carbonization temperature of 350 °C has excellent adsorption performance when the initial concentration of uranium solution is 32 ppm at pH 7.5.

As a new type of lightweight nano-porous amorphous carbon material, this carbon aerogel has many excellent properties.

This work presents a simple, low cost and controllable strategy for functionally graded programming of novel carbon aerogel. This carbon aerogel has great potential for application in various fields such as uranium recovery, wastewater treatment, sound absorption and shock absorption.

A core challenge of assessing regional agricultural drought vulnerability (RADV) is to reveal what vulnerability factors, under which kinds of synergistic combinations and at what strengths, will lead to higher vulnerability: namely, the influence patterns of RADV.

A two-phased grey rough combined model is proposed to identify influence patterns of RADV from a new perspective of learning and mining historical cases. The grey entropy weight clustering with double base points is proposed to assess degrees of RADV. The simplest decision rules that reflect the complex synergistic relationships between RADV and its influencing factors are extracted using the rough set approach.

The results exemplified by China's Henan Province in the years 2008–2016 show higher degrees of RADV in the north and west regions of the province, in comparison with the south and east. In the patterns with higher RADV, the higher proportion of agricultural population appears in all decision rules as a core feature. A smaller quantity of water resources per unit of cultivated land area and a lower adaptive capacity, involving levels of irrigation technology and economic development, present a significant synergistic influence relationship that distinguishes the features of higher vulnerability from those of the lower.

The proposed grey rough combined model not only evaluates temporal dynamics and spatial differences of RADV but also extracts the decision rules between RADV and its influencing factors. The identified influence patterns inspire managerial implications for preventing and reducing agricultural drought through its historical evolution and formation mechanism.

A radial offset jet has the flow characteristics of a radial jet and an offset jet, which are encountered in many engineering applications. The purpose of this paper is to study the dynamics and mass transfer characteristics of the radial offset jet with an offset ratio 6, 8 and 12.

Three turbulence models, namely the SST k-? model, detached eddy simulation model, and improved delayed detached eddy simulation (IDDES), were applied to the radial offset jet with an offset ratio eight and their results were compared with experimental results. The contrasting results, such as the distributions of mean and turbulent velocity and pressure, show that the IDDES model was the best model in simulating the radial offset jet. The results of the IDDES were analyzed, including the Reynolds stress, turbulent kinetic energy, triple-velocity correlations, vertical structure and the tracer concentration distribution.

In the axisymmetric plane, Reynolds stresses increase to reach a maximum at the location where the jet central line starts to be bent rapidly, and then decrease with increasing distance in the radial direction. The shear layer vortices, which arise from the Kelvin-Helmholtz instability near the jet exit, become larger scale results in the entrainment and vortex pairing, and breakdown when the jet approaches the wall. Near the wall, the vortex swirling direction is different at both front and back of attachment point. In the wall-jet region, the concentration distributions present self-similarity while it keeps constant below the jet in the recirculation region.

The radial offset jet with other offset ratio and exit angle is not considered in this paper and should be investigated.

The results obtained in this paper will provide guidance for studying similar flow and a better understanding of the radial offset jet.

This study analyzes the factors which affect the alfalfa cultivation acreage in China and estimates the development of alfalfa planting by the supply model.

Based on the characteristics and actual conditions of alfalfa cultivation in China, a naïve empirical model was created to analyze the impact of various influencing factors on the cultivation acreage of alfalfa.

The analysis of influential factors shows that China's alfalfa planting conforms to naïve price behavior. The prices of alfalfa and per capita arable land occupancy have a positive effect on the cultivation acreage, while the price of competitive crops and transportation costs have a negative effect on the production of alfalfa. Lastly, the 2012 alfalfa subsidy policy has a significant negative impact on alfalfa cultivation acreage.

Due to the limited research on alfalfa supply in China, there is a lack of available research data and statistical data. A large number of data in this study are mainly indirect data derived and calculated from other industrial data. The measurement results may not be fully accurate.

This study represents the first empirical analysis of the characteristics of the factors influencing alfalfa cultivation acreage in China. The secondary data were used to analyze the influence of various control variables on the cultivation acreage of alfalfa, which is different from existing research.