The formed transfer film on the counterpart surface and tribological properties of PTFE composites filled with Al2O3 or SiO2 were investigated in this paper. The results indicated that under the same friction conditions, the friction coefficients of SiO2/PTFE and Al2O3/PTFE are very close to each other, but the wear resistance of SiO2/PTFE is superior to that of Al2O3/PTFE. According to the measured data, the micro-hardness and elastic modulus of the transfer film for SiO2/PTFE are much better than those of Al2O3/PTFE. In addition, the interfacial adhesion strength between the transfer film of SiO2/PTFE and the counterface is higher. It can be proved that the mechanical properties of transfer films for PTFE composites vary with different fillers and the friction transfer film with better adhesion strength and mechanical property is useful to improve the tribological properties of the composite.

Direct current field (DCF) has been applied on an aluminising specimen and powder aluminising agents to overcome conventional powder pack aluminising (CPA)'s shortcomings of high treating temperature, long soaking time and low efficiency in utilising aluminising media. The specimen in the shape of plate or tube was taken as cathode of the DCF. The anode in the shape of plate or column paralleled to the specimen. Effects of DCF on CPA have been studied. The treated case's microstructure, phase, thickness and oxidation resistance have been investigated. The results show that DCF has the function of enhancing aluminising with great energy saving, even at a temperature below 750uC. The aluminised case endows plain carbon steel with superior resistance to oxidisation in air at a high temperature of 850uC. Mechanisms of DCF's effects to CPA have been proposed, which were discussed from two aspects of the DCF's thermal and nonthermal effects to the aluminising process.

A low-temperature silicon pack cementation has been developed by applying direct current field (DCF) between the treated sample and the powder agents. The cross-sectional microstructures, coating thickness and high temperature oxidation resistance after siliconizing under different processes were investigated. The results show that DCF can significantly reduce the treating temperature and heating duration comparing with the conventional silicon pack cementation, the heating temperature could be lowered to 750°С from higher than 1050°С normally used. When the treating temperature was 800°С with appropriate intensity of DCF, the siliconizing coatings with thickness around 40μm was produced, while at this temperature, almost no coating could be formed by conventional silicon pack cementation，and the coating rapidly formed at lower temperature had good oxidation resistance below 700°С .

This paper analyzes the lateral control technology of autonomous semi-trailer trucks. Existing researches on the lateral control algorithm of semi-trailer trucks focus on making the head-truck or trailer follow a track well while ignoring the motion characteristics during the turning process, leading to specific security issues. Meanwhile, it is difficult to cope with the complex and uncertain factors influencing lateral control effect, such as the curvature of the desired trajectory, the load, and the velocity of the semi-trailer truck. This paper proposes a parametric self-learning model predictive control (MPC) based on the Proximal Policy Optimization of One Step (OSPPO) method to solve these problems. After modeling the kinematics of the semi-trailer truck, a lateral motion controller for the relationship between the head-truck and trailer based on the MPC method is established. The traditional MPC method has difficulty in adapting to the changeable influencing factors. Thus, a deep reinforcement learning algorithm named OSPPO is introduced to improve the flexibility of the MPC method. OSPPO establishes the nonlinear mapping relationship between the critical parameter of the MPC method and the factors influencing control effect by self-learning, avoiding a large amount of labeled data for training. In simulations, Trucksim and Matlab were used to conduct co-simulation to verify the usefulness of the control method. The method was implemented on an autonomous semi-trailer truck for many outdoor scenes. The actual experimental results showed the validity and advantages of the proposed method.