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This paper aims to study the oxidation kinetics of the nanocrystalline Al ultrathin films. The influence of structure and composition evolution during thermal oxidation will be observed. The reason for the change in the oxidation activation energy on increasing the oxidation temperature will be discussed.

Al thin films are deposited on the silicon wafers as substrates by vacuumed thermal evaporation under the base pressure of 2 × 10⁻⁴ Pa, where the substrates are not heated. A crystalline quartz sensor is used to monitor the film thickness. The film thickness varies in the range from 30 to 100 nm. To keep the silicon substrate from oxidation during thermal oxidation of the Al film, a 50-nm gold film was deposited on the back side of silicon substrate. Isothermal oxidation studies of the Al film were carried out in air to assess the oxidation kinetics at 400-600°C.

The activation energy is positive and low for the low temperature oxidation, but it becomes apparently negative at higher temperatures. The oxide grains are nano-sized, and γ-Al₂O₃ crystals are formed at above 500°C. In light of the model by Davies, the grain boundary diffusion is believed to be the reason for the logarithmic oxidation rate rule. The negative activation energy at higher temperatures is apparent, which comes from the decline of diffusion paths due to the formation of the γ-Al₂O₃ crystals.

It is found that the oxidation kinetics of nanocrystalline Al thin films in air at 400-600°C follows the logarithmic law, and this logarithmic oxidation rate law is related to the grain boundary diffusion. The negative activation energies in the higher temperature range can be attributed to the formation of γ-Al₂O₃ crystal.

This paper aims to propose a hybrid force/position controller based on the adaptive variable impedance.

First, the working space is divided into a force control subspace and a position subspace, the force control subspace adopts the position impedance control strategy. At the same time, the contact force model between the robot and the surface is analyzed in this space. Second, based on the traditional position impedance, the model reference adaptive control is introduced to provide an accurate reference position for the impedance controller. Then, the BP neural network is used to adjust the impedance parameters online.

The experimental results show that compared with the traditional PI control method, the proposed method has a higher flexibility, the dynamic response accommodation time is reduced by 7.688 s and the steady-state error is reduced by 30.531%. The overshoot of the contact force between the end of robot and the workpiece is reduced by 34.325% comparing with the fixed impedance control method.

The proposed control method compares with a hybrid force/position based on PI control method and a position fixed impedance control method by simulation and experiment.

The adaptive variable impedance control method improves accuracy of force tracking and solves the problem of the large surfaces with robot grinding often over-polished at the protrusion and under-polished at the concave.

The purpose of this paper is to report the effect of cerium addition on plating rate, microstructure and electrochemical behaviour of electroless nickel‐phosphorus coatings.

The methodology comprised preparation of coatings with different concentration of cerium added in plating bath by electroless, then test coating properties by SEM, XRD and electrochemical workstation.

Coatings prepared with 10 mg/L cerium added in electroless bath have the best corrosion resistance and high deposition rate, smooth and mirror‐like micrograph.

The nickel‐phosphorus coating has obtained best corrosion resistance performance (icorr=1.35 μA cm⁻²) when cerium addition concentration is 10 mg L⁻¹.

In order to explore the damaging effect of behind-armor debris of explosively formed projectile (EFP) attack on the top armor of tank and the internal parts of vehicles, a method of damage probability calculation based on experiments is proposed.

The equivalent target structure of rear-effect damage of the equipment and personnel in the vehicle is determined based on the analysis of the vulnerability of internal equipment and personnel in the tank. The experimental scheme to obtain the density distribution of behind-armor debris is designed, and the calculation model of the damage probability of cavitating antipersonnel debris to the key components of the vehicle is given in the range of scattering angles and different broken pieces.

The examples show that the damage probability calculation model can be used in the process of evaluating the damage of the equipment and personnel in the tank by behind-armor debris.

An experimental model based on the analysis of the vulnerability of the equipment and personnel is proposed to calculate the damage probability from debris falling on the equipment and personnel in the vehicle. The results are of great value to the calculation of damage evaluation of the equipment and personnel in the tank.

The purpose of this paper is to actively calibrate power density to match the application requirements with as small an actuator as possible. So, this paper introduces shape memory alloy to design variable stiffness elements. Meanwhile, the purpose of this paper is also to solve the problem of not being able to install sensors on shape memory alloy due to volume limitations.

This paper introduces the design, modeling and control process for a variable stiffness passive ankle exoskeleton, adjusting joint stiffness using shape memory alloy (SMA). This innovative exoskeleton aids the human ankle by adapting the precompression of elastic components by SMA, thereby adjusting the ankle exoskeleton’s integral stiffness. At the same time, this paper constructs a mathematical model of SMA to achieve a dynamic stiffness adjustment function.

Using SMA as the driving force for stiffness modification in passive exoskeletons introduces several distinct advantages, inclusive of high energy density, programmability, rapid response time and simplified structural design. In the course of experimental validation, this ankle exoskeleton, endowed with variable stiffness, proficiently executed actions like squatting and walking and it can effectively increase the joint stiffness by 0.2 Nm/Deg.

The contribution of this paper is to introduce SMA to adjust the stiffness to actively calibrate power density to match the application requirements. At the same time, this paper constructs a mathematical model of SMA to achieve a dynamic stiffness adjustment function.

This paper aims to study the corrosion inhibition behavior of imidazopyridine and its three derivatives on brass.

The authors performed weight loss experiments, electrochemical experiments including the polarization curve and electrochemical impedance spectrum, corrosion morphology observation using scanning electron microscope (SEM) and atomic force microscope (AFM) and surface composition analysis via X-ray photoelectron spectroscopy (XPS) to analyze the corrosion inhibition behavior of imidazopyridine and its three derivatives on brass by using quantum chemical calculation (Gaussian 09), molecular dynamics simulation (M-S) and Langmuir adsorption isotherm.

According to the results, imidazole-pyridine and its derivatives were found to be modest or moderately mixed corrosion inhibitors; moreover, they were spontaneously adsorbed on the metal surface in a single-layer, mixed adsorption mode.

The corrosion inhibition properties of pyrazolo-[1,2-a]pyridine and its derivatives on brass in sulfuric acid solution were analyzed through weight loss and electrochemical experiments. Moreover, SEM and AFM were simultaneously used to observe the corrosion appearance. Furthermore, XPS was used to analyze the surface. Then, Gaussian 09 and M-S were combined along with the Langmuir adsorption isotherm to investigate the corrosion inhibition mechanism of imidazole-[1,2-a]pyridine and its derivatives.

The purpose of the investigation was to research the best process of electroless nickel (EN) plating on AZ91D magnesium alloy and the performance of EN plating coating.

Through single factor test and orthogonal test, EN plating on AZ91D magnesium alloy was researched. The plating rate and porosity were analyzed. The coating appearance of EN plating coating and magnesium alloy substrate was evaluated. The electrochemical properties of EN plating coating and substrate were researched using electrochemical workstation, and their compositions and structure were examined using X-ray diffraction and scanning electron microscopy.

The results made by combination of experimental and orthogonal test showed that the best formula of EN plating was 8.8 g·L⁻¹ nickel ion, 25 g·L⁻¹ lactic acid, 28 g·L⁻¹ reducing agent, 1.8 ml·L⁻¹ corrosion inhibitor, 1 mg·L⁻¹ stabilizer, temperature at 85°C and pH value at 5.5. The plating was uniform, dense and with no cracks. The electrochemical tests showed that the corrosion resistance of EN plating was better than that of magnesium alloy substrate.

The results indicated that the corrosion resistance of magnesium alloy improved markedly after EN plating at the best formula and the plating covered magnesium alloy completely.

Traditional visual simultaneous localization and mapping (SLAM) systems are primarily based on the assumption that the environment is static, which makes them struggle with the interference caused by dynamic objects in complex industrial production environments. This paper aims to improve the stability of visual SLAM in complex dynamic environments through semantic segmentation and its optimization.

This paper proposes a real-time visual SLAM system for complex dynamic environments based on YOLOv5s semantic segmentation, named YLS-SLAM. The system combines semantic segmentation results and the boundary semantic enhancement algorithm. By recognizing and completing the semantic masks of dynamic objects from coarse to fine, it effectively eliminates the interference of dynamic feature points on the pose estimation and enhances the retention and extraction of prominent features in the background, thereby achieving stable operation of the system in complex dynamic environments.

Experiments on the Technische Universität München and Bonn data sets show that, under monocular and Red, Green, Blue - Depth modes, the localization accuracy of YLS-SLAM is significantly better than existing advanced dynamic SLAM methods, effectively improving the robustness of visual SLAM. Additionally, the authors also conducted tests using a monocular camera in a real industrial production environment, successfully validating its effectiveness and application potential in complex dynamic environment.

This paper combines semantic segmentation algorithms with boundary semantic enhancement algorithms to effectively achieve precise removal of dynamic objects and their edges, while ensuring the system's real-time performance, offering significant application value.

The purpose of this paper is to prepare composite micro-arc oxide coatings with better wear resistance and corrosion resistance.

A nickel powder composite micro-arc oxide film was prepared on the surface of the magnesium alloy by the method of organically combining ultra-fine Ni powder with micro arc oxidation film layer. In this experiment, the changes in the corrosion resistance and microstructure of the composite film layer after adding Ni powder were studied, and the effect of the addition of glycerin on the corrosion resistance of the film layer was analyzed.

The results show that the ultra-fine nickel powder was successfully prepared by the liquid phase reduction method, and the micro-arc oxidation process was modified under the optimal addition amount. The surface of the micro-arc oxide film made of ultra-fine nickel powder was found by SEM to have smooth surfaces and few holes. According to X-ray diffraction analysis, the phase composition of the micro-arc oxide film layer was Mg, Ni, NiSiO₄, MgNi (SiO₄) and Mg₂SiO₄. According to the results of electrochemical tests, the corrosion resistance of the micro-arc oxidation composite film layer was improved after the addition of ultra-fine Ni powder, the corrosion current was greatly reduced and the impedance has been improved. And after adding glycerin, the surface of the film layer becomes denser, and the corrosion resistance of the micro-arc oxide film is significantly improved.

Through this experimental research, a micro-arc oxide coating of powder composite magnesium alloy was successfully prepared. The corrosion resistance of the micro-arc oxidation film layer has been improved, and certain functions had been given to the micro-arc oxidation composite film, which has increased the application field of magnesium alloys.

The purpose of this paper is to study the effect of temperature on Zn–Ni alloys in ChCl–Urea.

Based on cyclic voltammetry experiments, the deposition behavior and kinetics of the Zn–Ni alloy are studied. The nucleation process of the Zn–Ni alloy is studied in detail via chronoamperometry experiments. The effects of the deposition temperature on the microstructure, Ni content and phase composition of Zn–Ni alloy coatings are investigated via scanning electron microscopy and X-ray diffraction (XRD) combined with classical thermodynamics.

The results show that with increasing temperature, the reduction peak shifts toward a more positive electric potential, which is beneficial for the co-electric deposition process, and the diffusion coefficient is estimated. With increasing temperature, the nucleation process of the Zn–Ni alloy becomes a three-dimensional instantaneous nucleation, the typical kinetic parameters are determined using the standard 3D growth proliferation control model and the Gibbs free energy is estimated. The Zn–Ni alloy coatings are prepared via normal co-deposition. With increasing temperature, the degree of crystallinity increases, the coating gradually becomes uniform and compact and the XRD peak intensity increases.

The nucleation process of the Zn–Ni alloy at different temperatures is analyzed. The diffusion coefficient D and Gibbs free energy are calculated. The contribution of the three processes at different temperatures is analyzed. The effect of temperature on the morphology of the Zn–Ni alloy coatings is studied.