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To expand the applications of graphene which has so far been limited by the expensive nature of single-layer graphene, the effects of varying percentages of low-cost functionalized multilayer graphene nanosheets in siloxane-modified organic coatings were studied. The hydrophobic organic siloxane–acrylic resin was prepared by solution polymerization of acrylic monomers, and the graphene nanosheets were functionalized using fluorosilane. The coatings were sprayed on the LY12 aluminum substrate, and the wettability, anticorrosion, conductive, and accelerated weathering behaviors were comprehensively examined. It is shown that the increasing addition of functionalized graphene nanosheets increases the water contact angle and the surface conductivity. At 5% graphene loading, coating–substrate adhesion remains almost unchanged, while the electrochemical impedance parameters revealed good anticorrosion performance up to 10% loading. The surface measurements and Fourier transform infrared spectroscopy (FTIR) results confirmed the photostabilization ability of graphene loading in acrylic coatings during the accelerated weathering test. Also, the mechanical properties of the coatings were not damaged during the exposure, and pitting corrosion sites were observed only on the 20% graphene-filled coatings after 1000 h of exposure. These integrated analyses of mechanical properties and environmental accelerated tests are beneficial to engineering applications of graphene coatings.

Safe diagnosability of discrete-event systems (DESs) is viewed as the first necessary step of fault-tolerant supervision in the literature. For safe diagnosable systems, it is required that not onl...

For the purpose of overcoming the lack of durability problems associated with superhydrophobic surfaces which hitherto has limited their use; we prepared multi-stimuli wettability response coatings using a mixture of fluorocarbon resin and urea-formaldehyde microcapsules filled with fluorosilane via interfacial polymerization process. The microcapsules are of good thermal stability and can be triggered to release their core content on exposure to atmospheric conditions resulting in the increase in the water contact angle from 97° to 151°. The prepared coatings gave good adhesion strength, and also showed an increase in the hydrophobic property after undergoing scratch, solvent and UV accelerated aging test. In addition, they offered good self-healing of the hydrophobic property after an initial loss due to alkaline immersion and oxygen plasma etching. The electrochemical measurements revealed a remarkable impedance recovery and suppression of corrosion activities, suggesting them to be a potential candidate material for corrosion protection.

A synergistic inhibition study was carried out on an aluminium/copper galvanic coupling model in neutral aerated NaCl solution using scanning vibrating electrode technique (SVET). The approach allows the simulation of the local micro-galvanic cells of AA2024-T3 obtained from the potential difference between the intermetallic particles (IMPs) and the aluminium matrix. The inhibition effect of CeCl3 and 3-Amino-1,2,4-triazole-5-thiol (ATAT) was demonstrated by the reduction in the galvanic current density over Al and Cu surfaces. An improved inhibition from positive synergistic effect was revealed by the combination of the two inhibitors after 24 h of immersion, with the best inhibition recorded for Ce1.5ATAT3.5. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterize the Ce- and ATAT-based complex film formed and to illustrate the mechanism of inhibition.

Pure Al 2024 coating and Al 2024-Al2O3 composite coatings were deposited on AA 2024-T3 alloy substrates using low-pressure cold gas spray (LPCGS). The content of Al2O3 in the feedstock was 20 wt%, 40 wt% and 60 wt%, respectively. The porosity, surface roughness, adhesion and surface residual stress of the coatings were analyzed. Electrochemical tests were carried out in neutral 3.5 wt% NaCl solution to evaluate the effects of Al2O3 on the corrosion behavior of the coatings. The results showed that the Al 2024–20 wt% Al2O3 composite coating possessed the lowest porosity (0.55%), relatively higher adhesion strength (50.68 MPa) and surface residual compressive stress (48.3 MPa) among the cold sprayed coatings. The results of corrosion tests revealed that the cold sprayed coatings provided sacrificial anode protection for the AA 2024-T3 substrate and that Al 2024–20 wt% Al2O3 composite coating exhibited the best corrosion resistance.

The anti-corrosion performance of Zn and Zn15Al organic coating was investigated mainly by neutral salt spray test and electrochemical impedance spectroscopy. X-ray diffraction, scanning electron microscope and energy disperse spectroscopy were applied to analyze the corrosion behavior of the coating during the test. The facilitated formation of protective corrosion product simonkolleite on the Zn15Al coating surface was observed. Also, layered double hydroxides (LDH) consisting of Zn2+ and Al3+ were detected at the interface of coating/steel substrate of Zn15Al. This LDH was believed to function as ion exchanger that prevents Cl− from contacting the steel substrate.

Snowmelt salts and deicing additives which are used to remove the snow/ice in winter make the pavement experience diverse and complex actions such as freeze-thaw (F-T) cycles and salt immersion. Meanwhile, interface damage of asphalt-aggregate is a major reason for the decay of mixture properties. So, the interface properties under the impacts of snowmelt salt and F-T cycles were investigated in this paper. Three factors including salt concentration, soaking time and F-T cycles were considered based on the service condition of the pavement. ‘Sandwich’ specimens of asphalt-aggregate were prepared in the laboratory. Also, pull-off tensile test was conducted by universal test machine. Digital image processing technology was employed to analyze the interface failure mode. Results indicated that the selected three factors presented significant effects on moisture absorption and pull-off tensile strength (POTS). All of the POTS at low, medium and high temperatures decreased after conditioning. And the pull-off tensile strength loss (POTSL) after salt solution soaking and F-T cycles were all higher than the pure water soaking one. The power model can be used to describe the composite damage degree imposed by different factors. The coupling actions of salt immersion and F-T cycles would induce the failure mode variety. Adhesive failure was prone to occur at low temperature under the condition of low salt concentration and F-T cycles. Erosion effect of high concentration solution would induce the adhesive failure at medium temperature.

The effects of low-cost graphene nanosheets in organic coatings were investigated. The hydrophobic organic siloxane-acrylic resin was synthesized by solution polymerization of acrylic monomers while the graphene nanosheets were modified using fluorosilane, and applied on LY12 aluminum substrate via spraying and a two-step coating system. The superhydrophobic, conductive, anticorrosion, self-cleaning, oleophilic and physical behaviors were comprehensively characterized. The results obtained revealed that addition of modified graphene increases the surface conductivity (≥ 2 μS/cm) and the water contact angle (≥ 152°) with low sliding angle (≤ 7°). The polarization measurement showed a positive shift in the corrosion potential signifying an inhibition of the cathodic reaction. Also, the two-step coated sample gave a good corrosion protection barrier as further confirmed by the electrochemical impedance parameters. The coating revealed good resistance to dirt adhesion, and its superhydrophobic-oleophilic property offered a promising application in oil-water separation. The physical integrity of the coatings was not extensively affected including after 120 days of outdoor exposure to snowing, de-freezing and surface wetting.

A new corrosion inhibitor, cerium malate, was synthesized. Its inhibiting behaviour on coupled Al2Cu-Al2CuMg-Al, Al2CuMg-Al and Al2Cu-Al was studied. Cerium malate is effective in corrosion inhibition of the three coupled systems. The inhibition mechanism of cerium malate on pitting corrosion of Al2CuMg and Al2Cu phases in AA 2024-T3 was analyzed by scanning vibrating electrode technique (SVET), atomic force microscopy (AFM) and scanning kelvin probe force microscopy (SKPFM). The results indicate that cerium malate has good inhibiting effect on AA 2024-T3.

Due to the practical and theoretical importance, failure prediction of discrete-event systems (DESs) has received increasing attention recently. In this paper, the predictability of failure events in decentralized DESs is investigated. The main contributions are as follows. First, the notion of copredictability of DESs is formalized under the decentralized framework to capture the feature that the occurrences of failure events can be predicted based on at least one local observation. It is deducted that the copredictability is weaker than the predictability but stronger than the codiagnosability. Second, in order to achieve the performance of prediction, a nondeterministic automaton called coverifier is constructed from the given system. Third, the necessary and sufficient condition for verifying the copredictability of DESs based on the coverifier is presented, which generalizes the main results by Genc and Lafortune from the centralized systems to the decentralized setting. It is worth noting that both constructing the coverifier and verifying the copredictability can be realized with polynomial complexity in the number of states and events of the system. Note to Practitioners —The research in this paper is motivated by the following practical problem. Before failure events occur in a manufacturing system, can engineers predict the occurrences based on the observation record of the system? This paper aims to investigate the predictability issue of discrete-event systems under a decentralized framework by introducing the notion of copredictability. In order to verify the copredictability of systems, an approach is proposed by constructing the coverifier. In particular, the verification is polynomial-time.

The inhibition of AA2024-T3 corrosion by the synergistic combination of 3-Amino-1,2,4-triazole-5-thiol (ATAT) and cerium chloride in sodium chloride solution is assessed. Analysis of electrochemical impedance spectroscopy results show improved corrosion inhibition for the inhibitor combination by increased charge transfer resistance. Scanning vibrating electrode technique was utilized for corrosion current monitoring and quantification. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry were utilized to characterize the ATAT/Ce based film and to explain the mechanism of inhibition. The obtained results demonstrate a good potential of the inhibitor combination for improved suppression of corrosion processes.

Diagnosability is an important characteristic indicator to determine whether the system is stable and reliable. In this paper, the general architecture of event-state-combination diagnosability is investigated. The contributions are threefold. First, the notion of event-state-combination diagnosability is formalized. Roughly speaking, an event-state-combination diagnosable system means that not only each combined fault can be detected, but also the system can determine whether it will work permanently in the failure states after the combined fault occurs. Then, an automaton with new information structure, called event-state-combination verifier, is constructed, which can be used for the verification of the event-state-combination diagnosability. Finally, the necessary and sufficient conditions for verifying whether the system is event-state-combination diagnosable is presented, that is, the event-state-combination verifier does not have any failure confused cycle.

The demand of the market makes the requirements for the load capacity of UAVs(unmanned aerial vehicles) become higher and higher. Due to the high reliability, strong robustness and fast response capability, the multi-UAVs collaborative control system is of great significance. The traditional multi-UAVs cooperative control system is limited by the data transmission capacity of wireless networks. The subordinate UAV can move in the direction of the passive force passed by load to reduce the external force and follow the main UAV. The collaborative control method for multi-UAVs based on ADRC(Active Disturbances Rejection Control) uses that passive force as the controlled variable. Compensating the passive force to eliminate the resultant external force of the subordinate UAV, and the subordinate UAV can follow the main UAV in real time.

With the development of microelectronics and computer technology, the power and frequency control of ultrasonic surgical system become more and more accurate. Because of its good medical characteristics, the ultrasonic scalpel is widely used in the medical field for incision and hemostasis, hepatobiliary tumor aspiration, phacoemulsification, osteotomy and liposuction. Therefore, research on the ultrasonic surgical system is getting more attention in academic and industrial fields. The main purpose of this paper is to propose a research method of an ultrasonic surgical system with precise control of the power and frequency output. After briefly introducing the medical mechanism of the ultrasonic scalpel and the purposes of the research, the ultrasonic surgical system is mainly discussed from the following aspects: the structural principle of the main circuits including the ultrasonic drive control circuit and the power output isolation circuit, and the control algorithm for controlling the output power and frequency based on the analysis of the transducer admittance. In addition, experimental results about verification for the applicability of the control algorithm are given and analyzed. Finally, the research of the ultrasonic surgical system is summarized.

Predictability is an important property which is used to predict the failures which is not observable for the sensors straightly before they occur. In an automation system, in addition to the failure caused by a single event, there also exist pattern failures caused by event strings composed of multiple events. In order to prevent some local sites malfunction, the issue of reliable predictability of patterns is considered in this paper, where the prediction information may be distributed at physically separated sites. Our contributions are listed mainly as follows: Firstly, the k -reliable pattern copredictability in decentralized DESs is defined with formal languages. Generally speaking, for a decentralized system where there are r local sites, it is said to be k -reliably pattern copredictable ( 1 ≤ k ≤ r ) if there are at least r − k + 1 local agents which can predict every occurrences of the pattern failure for every pattern failure, it indicates that the prognostication capability will be maintained while r − k local sites in malfunction state. Then two nondeterministic automata respectively named codiagnoser and coverifier from the given system are constructed in this paper, and two algorithms of verifying the reliable copredictability of pattern are presented by constructing the codiagnoser and coverifier respectively for the purpose of attain the capability of prognostication. Especially, two necessary and sufficient conditions under the codiagnoser and coverifier are proposed. Moreover, for the decentralized DESs, the verification algorithm related to the k -reliable pattern copredictability is proposed after presenting the necessary and sufficient conditions for reliable pattern copredictability. It is worth noting that a polynomial complexity algorithm is used in constructing the coverifier and verifying the k -reliable pattern copredictability.

Cerium malate (CeMal) was tested as a corrosion inhibitor for AA2024-T3 in this work. Corrosion inhibition on bare AA2024-T3 indicated that the inhibiting effect was a result of the synergistic effect of cerium cations and maleic anions. The corrosion of AA2024-T3 was stagnated by greatly reducing the corrosion current when CeMal was present in NaCl solutions. CeMal was adsorbed on the surface of AA2024-T3 forming a protective film in the initial stage. Then, cerium cations transformed to cerium oxide/hydroxides, precipitating on the cathode sites to inhibit the further corrosion. The electrochemical impedance spectra results of the sol–gel coatings proved that CeMal was an effective corrosion inhibitor in the sol–gel coatings to provide corrosion protection for AA2024-T3.

Sparse subspace clustering algorithm (SSC) is one of the efficient methods for hyperspectral imagery (HSI) segmentation. However, it does not consider the spectral information and space information. In this paper, we propose a novel method Gaussian Kernel Dynamic Similarity Matrix Based Sparse Subspace Clustering (briefly GKD) which constructs adjacency matrix using sparse representation coefficient matrix and similarity matrix. Firstly, the sparse representation coefficient matrix is obtained by using the sparse subspace clustering model, and the similarity between pixel points after PCA dimension reduction is calculated according to the Gaussian Kernel function. Then, the similarity matrix of the graph is constructed by sparse coefficient matrix and Gaussian similarity. Finally, the cluster result can be received by applying the spectral clustering to the similarity matrix. The data experiments conducted in several datasets illustrate the improvements over the current state-of-the-art.

Polymeric coatings prevent metal materials from corrosion. Nevertheless, the degradation of the coatings in seawater by microorganisms is almost unknown. In this work, we explored the degradation of the aluminum/epoxy coating in sterile seawater and seawater inoculated with Pseudomonas sp. by electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy and contact angle test. The decreases in the corrosion resistance of the coating were significantly higher in seawater inoculated with Pseudomonas sp. than in sterile seawater. The mature biofilm formed on the coating and then the extensive under-coating corrosion occurred in seawater inoculated with Pseudomonas sp.. These results revealed that Pseudomonas sp. significantly decreased the corrosion resistance of the coating and might degrade the coating. Some bulges and tiny holes were observed on the coating in seawater inoculated with Pseudomonas sp.. The contents of Al and O significantly respectively decreased and increased on the surface of the coating in seawater inoculated with Pseudomonas sp. relative to those on the surfaces of the coating without immersion and in sterile seawater. The absorbance of the C-OH peak for the coating immersed in seawater inoculated with Pseudomonas sp. was significantly higher than that for the coating without immersion and the coating immersed in sterile seawater. Moreover, Pseudomonas sp. decreased the water contact angle of the coating surfaces. The results demonstrated that Pseudomonas sp. degraded the aluminum/epoxy coating through decomposing the aluminum and oxidizing the epoxy to forming hydroxyl.

Corrosion inhibition of tolytriazole for galvanized steel was studied in 5 mM NaCl by using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET). The results of EIS and polarization tests indicate that tolytriazole is effective in corrosion inhibition of galvanized steel. As the concentration of tolytriazole is increased to 0.01 M, the inhibiting efficiency reaches above 98%. The low values of anodic and cathodic current density in SVET maps suggest that the complex of tolytriazole with galvanized steel inhibits the anodic and cathodic reactions of corrosion of zinc. The adsorption behaviour of tolytriazole is found to conform to Langmuir adsorption isotherm, which is typical chemical adsorption.

The guaranteed cost control problem for mode-dependent time-delay Markov switching singular systems with norm-bounded uncertain parameters is discussed. Based on delay-dependent linear matrix inequalities, sufficient conditions which ensure the nominal Markov switching singular system to be regular, non-impulsive and stochastically stable are derived by quoting a mode-dependent Lyapunov functional and applying Moon’s inequality for cross terms. The sufficient conditions involve two cases. Case 1: the time delays are known; Case 2: the time delays are unknown, but the difference of the largest and the smallest time delay is known. Then, the problem is solved to design a state-feedback control law such that the closed-loop system is stochastically stable and the corresponding cost function value is not bigger than a specified upper bound for all the admissible uncertainties. Finally, optimization algorithms are given to find the optimal performance indexes.

This paper is concerned with the delay-dependent robust resilient $$H_\infty $$ control problem for uncertain singular time-delay system with Markovian jumping parameters. First, a delay-dependent bounded real lemma in terms of linear matrix inequalities is established, which guarantees the nominal Markovian jump singular system to be regular, impulse free and stochastically stable. Then, based on this condition, sufficient conditions in terms of LMIs are given to ensure the existence of the desired robust resilient $$H_\infty $$ controllers. The uncertainties of the controllers are considered in two cases, that is the additive controller gain uncertainties and the multiplicative controller gain uncertainties. Finally, numerical examples illustrate the applicability of the results proposed in this paper.

The surface modification of zinc particles using phosphoric acid was conducted to improve the corrosion resistance of Cold galvanizing coatings. The modified zinc particles were characterized by Scanning Electron Microscope (SEM) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET) were performed to investigate the corrosion protection mechanism of the coating. The electrochemical activity of zinc particles were found decreased because of the formation of Zn 3 (PO 4 ) 2 ·4H 2 O on the surface of the particle. Little lamellar-shaped phosphate was also observed after surface modification. The best anti-corrosion performance of the coating was achieved when using zinc particles modified with 1% phosphoric acid as the fillings. This improvement was accomplished by the combined effect of reduced electrochemical activity of surface modified zinc particles and block effect from lamellar-shaped phosphate.

In this work, urea-formaldehyde (UF) microcapsules loaded with tung oil were prepared by in-situ polymerization. The mean diameter of the obtained microcapsules was 8.5 μm. The self-healing coating was prepared by the addition of 5 wt.% microcapsules into an epoxy matrix and then painted on the AA2024 substrate. The effect on the coating properties after the incorporation of microcapsules was investigated by adhesion tests and electrochemical impedance spectroscopy (EIS). It is found that 5 wt.% microcapsules in coating formulations did not impart a significant negative effect on coating properties. SEM and EIS tests were used to evaluate the self-healing effect. According to the fitting results of the EIS data on the scratched samples, the new film that formed by the polymerization of tung oil at the scratched area in the self-healing coating displays a resistance value of more than 106 Ω·cm2, which is much higher than 103 Ω·cm2 of the oxide layer in the neat epoxy coating. The neutral salt spray tests also confirm the good anti-corrosion performance of the self-healing coating.

In this paper, the problem of relative predictability of failure event occurrences is investigated. The notion of relative predictability is proposed for logical automata and the concept of...

The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria (SRB) was studied. The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB. The atomic force microscopy images show that after immersion for 15 days, the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB. The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample in the simulated seawater without SRB.

In the present work, the sub-micrometer containers were prepared using mesoporous silica particles (SBA-15) with parallel channels as reservoir and 8-hydroxyquinoline as corrosion inhibitor. Layer-by-layer assembling was used to construct a shell of polyelectrolytes around the silica particles. Release of 8-hydroxyquinoline from sub-micrometer containers was studied in response to acidic or alkaline pH values. The results of electrochemical impedance spectroscopy (EIS) show the improvement of corrosion resistance of epoxy coatings containing sub-micrometer containers. Self-healing ability of the epoxy coatings was provided by sub-micrometer containers, as evidenced by the results of scanning vibrating electrode technique (SVET).

Strong field sequential ionization of symmetric-top CH3I molecules is studied experimentally by using a combined method of femtosecond laser-induced impulsive alignment and time-of-flight mass spectrometry. Both alignment- and angular-dependent ion yields have been measured, and the sequential ionization of a multielectron has been discussed. It is found that the maximum ionization occurs when the polarization of probe laser is perpendicular to the internuclear axis of molecules, and the signal of fragment ion peaks at the polarization of the probe laser is parallel to the internuclear axis of molecules. The angular distribution of ions indicated that ionization of π-type orbitals corresponds to generation of charged parent ions and ionization of σ-type orbitals corresponds to generation of fragment ions. The sequential release of multielectrons for Coulomb explosion channels is studied by analysis of the time evolutions of multicharged In+ (n = 1–4) signals.

The notion of relative diagnosability is proposed for logical automata and the concept of diagnosable rate is introduced to characterize the diagnosability property of a discrete-event system, which takes values in the interval [0, 1]. The relationship between relative diagnosability and diagnosability introduced by Sampath et al. that relative diagnosability is weaker than diagnosability for discrete-event systems is analysed. Furthermore, a necessary and sufficient condition for relative diagnosability is presented. In particular, an opacity-based algorithm is developed to test the relative diagnosability, which is polynomial in the number of states of the system. In addition, the proposed algorithm may be used to deal with the problem of diagnosability.

Failure diagnosis and correction of discrete-event systems (DESs) have received considerable attention in recent years due to the practical and theoretical importance. As a continuation of our prior work on diagnosability of stochastic DESs (i.e., Liu et al., 2008; Liu and Qiu, 2008), this paper aims to investigate the correctability issue, where the considered system is equipped with a probabilistic structure to estimate the likelihood of events occurring. More specifically: (1) We formalize the notion of k -step corrective probability to calculate the correctability of stochastic systems. Roughly speaking, the k -step corrective probability represents the probability that the stochastic system may recover to accepted states from the current state within k steps. (2) By introducing the strategy of adjusting the transition probability of the current state of system, an optimal correction mechanism is presented to achieve the maximal k -step corrective probability. (3) In addition, a novel approach of the computation of supremal corrective probability is developed by constructing the decision tree after introducing the infinitely expandable states. Finally, an example for the evolution process of the voltage in a circuit system modeled by a stochastic automaton is provided to illustrate the proposed results.

A new inhibitor pigment, cerium tartrate was studied as a pigment in epoxy coatings. The results of release measurements of Ce ions from epoxy coating in 0.05 mol/L NaCl indicate that cerium ions are able to transport through the epoxy coating, which is a key characteristic of inhibitor pigment. The electrochemical impedance spectroscopy (EIS) shows that cerium tartrate is an effective pigment for improving the barrier effect of epoxy coatings on AA2024-T3. The self-healing ability of cerium tartrate in artificial defects was verified by scanning vibrating electrode technique (SVET).

Rotational dynamics of quantum state selected and unselected CH3I molecules in intense femtosecond laser fields has been studied. The orientation and alignment evolutions are derived from a pump-probe measurement and in good agreement with the numerical results from the time-dependent Schrodinger equation (TDSE) calculation. The different rotational transitions through nonresonant Raman process have been assigned from the Fourier analysis of the orientation and alignment revivals. These revivals are derived from a pump-probe measurement and in good agreement with the numerical results from the TDSE calculation. For the molecules in rotational state vertical bar 1, +/- 1, -/+ 1 >, the transitions can be assigned to Delta J = +/- 1, +/- 2, while for thermally populated molecules, the transitions are Delta J = +/- 2. Our results illustrate that the orientation and alignment revivals of the rotational quantum-state selected molecules give a deep insight into the rotational excitation pathways for the transition of different rotational states of molecules in ultrafast laser fields.

The automation and coordination of vehicle has provided novel development opportunities for both the improvement of traffic efficiency and the efficiency and safety of vehicles within the platoon so that the research of related technology had becoming more and more popular. In this paper, we evaluate five traditional vehicle platoon auto-driving control algorithms in the sinusoidal scenario with disturbance. The simulation is realized in the PLEXE, which is an extension of the widespread vehicle network simulator Veins that allows the visually realistic simulation of platooning systems(i.e., automated car-following) and the analysis of mixed scenarios. For disturbance model in sinusoidal scenario, Gaussian noise is leveraged, which is a common disturbance of all kinds of system. Simulations’ results indicate that, when the leader in the platoon driving with sinusoidal velocity with disturbance, Flatbed algorithm proposed by A. Ali, G. Garcia, and P. Martinet has higher stability and Anti-interference ability than the other four control algorithms. In addition, even under violent interference, this control law can maintain string stability (significant for platoon automation)and consistency of the platoon operations, such as consistent velocity and constant inter-vehicle gaps.

The fault recording monitoring system is a kind of automatic information recording equipment for distribution network that is put into operation all the year round. It is used to monitor the operation status of the power system to analyze the cause of the fault, quickly and accurately locate the fault occurrence point, monitor and verify the action characteristics of the relay protection automatic device, etc. Different from the centralized fixed structure of the traditional microcomputer-based fault recorder, we designed a modular distributed grid fault recording system with ultra-low-power characteristic. According to the precision complementary characteristics of the global positioning system (GPS) and the crystal clock signal, the GPS clock is used to calibrate the system clock to realize the microsecond high-precision clock, which meets the high requirements of synchronization acquisition of the three-phase current. The effectiveness of the proposed synchronization algorithm is validated by experiments on actual system.

With the increasing scale of the power grid, real-time monitoring requirements for on-site data of power systems in various countries around the world are getting higher and higher. The high-voltage distribution network is widely distributed, spanning rivers, rivers, mountains, deep valleys, jungles, and other complex and variable environments so that it is susceptible to short-circuit faults caused by various natural disasters and other environmental factors. Single-phase ground faults are also common in the grid, and working information and necessary alarm indications during network operation are also important. The real-time monitor of the line current is indispensable for short-circuiting faults, while ground faults need to monitor the zero-sequence voltage in the substation and call the original sampled data for analysis. When there is a transient short-circuit fault in the distribution network, the transmission line resumes operation after reclosing, but the hidden danger still exists. In the fault recording system, the data can be analyzed in time to avoid the fault happening again. For the permanent short-circuit fault, the fault still exists after the gate reclosing. The analyze of recorded data can avoid strong power transmission measures of the system which can reduce the secondary impact and minimize the loss caused by the fault. In response to these functional requirements, this paper designs a new fault recording system and introduces its hardware structure and function implementation.

Antibiotics are widely detected in the water environment, posing a serious threat to the health of humans and animals. The effect of levofloxacin (LOFL) on pollutant removal and the difference in the influence mechanisms at normal and low temperatures in constructed wetlands are worth discussing. A hydroponic culture experiment was designed with Iris pseudacorus L. at low and normal temperatures. LOFL (0–100 µg/L) was added to the systems. The results indicated that the removal of pollutants was affected most by temperature, followed by LOFL concentration. At the same concentration of LOFL, the pollutant removal rate was significantly higher at normal temperature than at low temperature. Low concentrations of LOFL promoted the degradation of pollutants except TN under normal-temperature conditions. Compared with the results at low temperature, the bacterial community richness was higher and the diversity of bacterial communities was lower under normal-temperature conditions. The genera and the function of bacteria were greatly affected by antibiotic concentration, temperature and test time. A series of microorganisms resistant to antibiotics and low temperature were identified in this study. The results will provide valuable information and a reference for our understanding of the ecological effects of LOFL.

Silica nanoparticles are used as additives to organic coatings to modify their properties. The interface of inorganic nanoparticles with an organic matrix can be a preferred location for accumulation of water. Surface treatment of nanoparticles with 3-glycidoxypropyltrimethylsilane (silane) is one way to reduce the water accumulation. In this work, using atomistic simulations (MD), we studied the effects of silane treatment on accumulation of water at the interface of nanoparticles. Three different epoxy phases and two methods of deposition of water were simulated. Water molecules were studied at two locations: (i) the interface of nanoparticles, and (ii) in the matrix of coatings. Additionally, the changes in the organic matrix due to surface treatment of nanoparticles were studied. The simulations show how silane treatment affects the interactions of water with nanoparticles in different epoxies, and also how silane treatment reduces the water accumulation in an organic matrix with nanoparticles.

It is known that microorganisms degrade many materials. However, very little is known about the biodegradation of marine coatings. In this study, we explored the degradation of epoxy resin varnish coating in sterile seawater and seawater inoculated with Pseudomonas putida by the coating permeability analysis, electrochemical impedance spectroscopy, contact angle test, scanning electron microscopy, Fourier transform infrared spectroscopy. The decrease in the corrosion resistance of the coating was significantly higher in seawater inoculated with Pseudomonas putida than in sterile seawater between 48 h and 25 days of coating immersion. The extensive under-coating corrosion appeared on the substrates in both seawater systems, but the corrosion in seawater inoculated with Pseudomonas putida was much more serious. These results suggested that Pseudomonas putida significantly decreased the corrosion resistance of the coating and might decompose the coating. Some pulverization and tiny holes were found on the coating in seawater inoculated with Pseudomonas putida. Moreover, the absorbance of the C OH peak for the unimmersed coating and the coating immersed in sterile seawater was significantly higher than that for the coating immersed in seawater inoculated with Pseudomonas putida. The results proved that Pseudomonas putida degraded the coating. The degradation could involve the hydroxyl oxidation.

The ionization processes of NH3 molecule are studied by photoelectron velocity map imaging technique in a linearly polarized 400-nm femtosecond laser field. The two-dimensional photoelectron images from ammonia molecules under different laser intensities are obtained. In the slow electron region, the values of kinetic energy of photoelectrons corresponding to peaks 1, 2, 3, and 4 are 0.27, 0.86, 1.16, and 1.6 eV, respectively. With both the kinetic energy and angular distribution of photoelectrons from NH3 molecules, we can confirm that the two-photon excited intermediate Rydberg state is A∼1 A 2 ′ ′ ( v 2 ′ = 3 ) state for photoelectron peaks 2, 3, 4, and the three peaks are marked as 1223 (2 + 2), 1123 (2 + 2), and 1023 (2 + 2) multi-photon processes, respectively. Then, peak 1 is found by adding a hexapole between the source chamber and the detection chamber to realize the rotational state selection and beam focusing. Peak 1 is labeled as the 1323 (3 + 1) multi-photon process through the intermediate Rydberg state E ∼ 1 A 1 ′ . The phenomena of channel switching are found in the slow electron kinetic energy distributions. Our calculations and experimental results indicate that the stretching vibrational mode of ammonia molecules varies with channels, while the umbrella vibration does not. In addition, we consider and discuss the ac-Stark effect in a strong laser field. Peaks 5 and 6 are marked as (2 + 2 + 1) and (2 + 2 + 2) above threshold ionization processes in the fast electron region.

Mechanical weeding is an efficient weeding method, which is of considerable significance to the paddy field ecosystem. However, traditional mechanical weeding methods can cause seedling damages due to the bending phenomenon of the seedling lines. Introducing computer vision and control technology to traditional mechanical weeding methods can help the system diagnose the bending phenomenon and avoid crushing the seedlings. In this paper, we propose a deep-learning-based method of seedling line bending diagnosis and guidance line extraction. To prove the proposed method effective in the mechanical weeding system, we choose the Faster Region-based Convolutional Network (R-CNN) and Single Shot MultiBox Detector (SSD) as the representative models of the single-phase method and the two-phase method. With a novel dataset of rice seedling images established, we compare and analyze the confidence and real-time performance of the trained models. The experimental results show that the Faster R-CNN model is better in terms of accuracy, yet the SSD model has more advantages in the speed. Comprehensively considering the system requiring and model performances, the SSD model is a better choice in the automatic rice avoidance system.

In this work, we used atomistic level simulations to study water molecules confined between an epoxy layer and alumina substrate. Water is responsible for many complex reactions at the interface of substrate, which makes understanding characteristic properties of water at this particular confinement essential. Three different confinement sizes were selected. The substrate is hydroxylated gamma alumina and the organic coating layer is constructed with epoxy molecules. Different properties such as density, mobility and displacement, inter-molecular structures, power spectra, and hydrogen bond energy of water molecules were obtained. The results are studied in connection with the size of confinement. It is shown that the properties of water in this type of confinement are different from the bulk water and as the size of confinement decreases, some of the unique behaviors of water molecules are revealed.

Fibers have been commonly used to enhance the cracking resistance of asphalt mixtures. However, the reinforcing actions of different fibers have presented diverse effects. Therefore, three kinds of fibers, including glass fibers, basalt fibers and steel fibers, were selected to investigate their influences on the low temperature properties and cracking resistance of asphalt mixtures in this paper. Indirect tensile testing (IDT) was conducted to obtain basic properties such as the Poisson’s ratio and moduli. The digital image correlation (DIC) technique was employed to measure the deformation and strain. The crack inhibition action was evaluated by the failure time. The results showed that the fiber type has no influence on the Poisson’s ratio of the mixture. However, the addition of fibers remarkably affects the mixture modulus. The modulus and ultimate tensile strength of the reinforced mixture decline after the addition of fibers. The gaps between the compressive and tensile moduli are also increased by the addition of fibers. Moreover, the addition of fibers not only substantially improves the mixture ductility but also delays the fracture process. The fiber reinforced asphalt concrete (FRAC) presents a higher fracture energy (FE) and dissipated creep strain energy (DCSE) than that of the control concrete. Among the selected fibers, basalt fibers exhibit optimal crack resistance performance, while steel fibers are not recommended due to their smooth appearance.

The recent development of the cold spray method has made it possible to deposit dense coating with good adhesion and with almost no change in the microstructure, which is promising in repairing damaged Al-based aircraft skin. In this work, the in-situ shot-peening-assisted low-pressure cold spray method was used to deposit Al-based dense coatings with good mechanical and corrosion protection properties on AA 2024-T3 alloy. The detailed microstructure, coating adhesion, and corrosion protection performance were systematically investigated. A dense microstructure with low porosity ( 45 MPa) is achieved for the coatings. By comparison, Al 5083 coating exhibited the optimum mechanical properties. The Al and Al 5083 coatings reveal similar pitting resistance and repassivation ability. During long-term immersion test (>480 h) the corrosion resistance of Al 5083 coating surpassed that of CP Al coating. In conclusion, Al 5083 coating has a good combination of mechanical and anti-corrosion properties.

The molecular dynamics (MD) method can be a reliable tool for studying of organic coating/metallic substrate systems, however its accuracy is limited to the force field governing the dynamics of systems. These systems can be divided into three parts: (i) organic phase, (ii) substrate, (iii) interface between the organic phase and substrate. In this work, three recent ReaxFF descriptions were selected. A set of complex experimental data and density functional calculations was selected as the reference point. The density and structural analysis of a wide range of crystalline organic compounds were studied. The density, structural analysis, and self-diffusion constant of water at room temperature were obtained. The glass transition temperature of three different cross-linked epoxy were obtained and compared with the reported experimental results. The interaction energies of different configurations of epoxy and water over an alumina substrate were studied. Additionally, the reaction of water with aluminum was studied. The accuracy of these ReaxFF descriptions in reproducing the reference data was assessed. The results show there is a single ReaxFF description for accurate simulation of C/H/N/O/Al systems, which enables atomistic simulations of complex epoxy coatings/aluminum substrates systems.

New insights on the effect of nature and number of polyelectrolyte (PE) shells on active anticorrosion potential of microcontainers (MCs) applied as pH-sensitive reservoirs in coatings for the protection of AA2024-T3 is reported. Mesoporous silica particles (MSP) were loaded with benzotriazole (BTA) and shelled with different polyelectrolyte multilayers (PEM), demonstrating pH sensitivity. Weak-weak polyelectrolyte (W-W PE) shells allow immediate release of inhibitor, but weak-strong polyelectrolyte (W-S PE) shells encourage slower, more controlled and prolonged release, as revealed by release profiles of BTA from microcontainers. Active anticorrosion protection characterizations of the coatings doped with microcontainers were carried out by electrochemical techniques (EIS, SVET) and salt spray tests. Results reveal dependence of active properties of coatings on the nature and number of polyelectrolyte multilayers of microcontainers. We anticipate that proper choice of PEMs on smart containers can aid controlled functionalization of active feedback systems.

The Generalized Iterative Closest Point(G-ICP) algorithm is a high-precision point cloud registration algorithm, which uses Euler angles to parameterize a rotation matrix. However, Euler angle parameterization has singularity at a specific angle, which leads to application limitations. In this paper, a new G-ICP algorithm has been proposed, in which the Lie algebra on so(3) is used to parameterize a rotation matrix and the Gauss-Newton method is employed to optimize the objective function of the G-ICP algorithm. The experimental results have demonstrated that our method performs well compared with the state-of-the-art G-ICP alorithm [1] and simultaneously holds better estimation accuracy of pose with fast convergence speed in the open RGB-D TUM datasets.

Automated and coordinated vehicle technology has becoming increasingly prevalent. In this paper, in terms of the fuel consumption and pollutant emissions, we proposed an S-velocity curve regulation, combined with a sinusoidal scenario to evaluate four classic vehicle platoon autopilot control algorithms. The simulation studies of different scenarios are implemented in an integrated simulation platform PLEXE, which is developed based on SUMO and OMNeT ++. For emission model in SUMO, we utilize PHEMlight, which is a simplified version of the Passenger car and Heavy duty vehicle Emission Model (PHEM) to replace the default one. Numerical simulations demonstrate that, when the leader driving with S-velocity curve, Cooperative Adaptive Cruise Control (CACC) proposed by PATH project has higher fuel efficiency and lower CO 2 emission than other three control laws. Moreover, this CACC algorithm can maintain string stability and more consistent operations (in terms of velocities and inter-vehicle gaps) even under sinusoidal scenario changed frequently.

An innovative method was put forward to fabricate superhydrophobic surface based on nanostructured zinc rich coatings via modifying the rough surface with perfluorodecyl triethoxysilane solution. The obtained superhydrophobic surface not only displays a static water contact angle of 153°and water sliding angle of 7°, but also exhibits an excellent reparability and self-cleaning ability during the field test. Water immersion test and electrochemical measurements demonstrated that this modification can improve the anticorrosion performance of the coating.

Highly dispersed nanometer BiVO4 on attapulgite (ATP) as hybrid inhibitor pigment was prepared using chemical bath deposition. Microscopy analysis shows that nanometer BiVO4 particles uniformly grow on attapulgite. The immersion and polarization tests show that ATP-BiVO4 inhibits corrosion of aluminium alloy 2024-T3. The EIS results indicate that the coating resistance of ATP-BiVO4 containing epoxy coating is approximately two orders of magnitude higher than that of the epoxy coating containing only attapulgite. The enhanced corrosion protection ability of ATP-BiVO4 containing epoxy coating can be ascribed to the combination of the barrier effect of ATP-BiVO4 and the inhibition effect of the released vanadate at the coating/substrate interface. The deposition of BiVO4 with inhibition ability on fillers provides a new way to develop hybrid inhibitor pigment.

Using organic coatings with high barrier property in combination with active corrosion protection can improve corrosion protection of aluminum alloys. In this work, 3-Amino-1,2,4-triazole-5-thiol (ATAT) was used as organic inhibitor in developing anticorrosion coatings for AA2024-T3. The delivery of ATAT was achieved by using smart microcontainers with ATAT that respond to pH change caused by corrosion reaction at the coating-substrate interface. The developed coatings with low concentration of smart microcontainers showed a slight reduction of barrier properties, but gained active corrosion protection capability. The resistance of the coatings reduced the rate of penetration of corrosive species and the active corrosion protection stopped the damaging reactions at the coating-substrate interface. The active corrosion protection is also evident in the case of coatings with mechanical damages, when the barrier property of coatings is compromised. Waterborne coatings with smart microcontainers for delivery of ATAT exhibited enhanced performance for corrosion protection of AA2024-T3.

This paper aims to investigate safe diagnosis of fuzzy discrete-event systems (FDESs) under the decentralized framework. The notion of safe codiagnosability of FDESs is formalized to capture the property of systems that each occurrence of failures can be detected by at least one local diagnoser with a certain degree before any unsafe forbidden operation is executed. After introducing a fuzzy automaton called the recognizer to distinguish the forbidden strings from the illegal language, a safe codiagnoser is constructed to perform decentralized safe diagnosis of FDESs. In particular, a necessary and sufficient condition of safe codiagnosability of FDESs is derived, which extends the existing main results of safe diagnosability of FDESs from the centralized setting to the decentralized case.