The real key structures of urban railway vehicle are costly and dangerous, but students majoring in relevant fields have to acquire skills needed to operate the key structures to get good jobs or do academic research easily. The virtual reality (VR) technology, which has been used in many fields, can provide students with a unique learning experience. The purpose of this paper is to investigate the impact of VR on the operational skills and cognitive load in students studying urban railway vehicle engineering. A virtual reality learning environment (VRLE) was designed to help students understand how a bogie is dismantled or assembled, thus enabling them to dismantle or assemble bogie. The experimental subjects were randomly divided into an experimental group and a control group, and each group contained 31 male and 9 female freshmen majoring in urban railway vehicle engineering. Corresponding pretests, teaching activities, and posttests were carried out according to the proposed teaching and experimental designs. The VRLE was used to teach the students in the experimental group, whereas the other group was taught by traditional teaching methods. The experimental results show that VR played a positive part in the students' acquisition of operational skills and the VRLE was helpful in reducing the cognitive load in the students when they were performing experiments. The results reveal that VR technology has a positive impact on the education in urban railway vehicle engineering.

Students' learning motivation and gains in the professional training are essential criteria for evaluating the vocational teaching level. This study designed the virtual reality guidance (VRG) system to teach the skills of urban railway vehicle overhaul. The VRG system aims to improve students' enthusiasm and gains from learning. The system has two modules, teaching and experiment modules, respectively. The teaching module added the independent design mode and evaluation mode to guide students to participate in and enjoy the teaching system actively. The experiment randomly divided 80 urban railway vehicle engineering students into the experimental and control groups. Participants underwent the entire pretest, teaching, and posttest process. The results show that the VRG system endows students with more effective operational skills learning rather than traditional teaching methods. Also, the novel system can guide students to discover their professional advantages and enhance their enthusiasm for professional learning.

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The oscillation phenomena for granular mixture within a vertically vibrated container are investigated with the event-driven method. The container consists of two rooms with equal size separated by a clapboard with certain height，and two kinds of granules with the radius of one twice as larger as the other are used. Investigation results indicate that the period of oscillation of granula sharply increases with the decrease of the ratio of density between two kinds of particles. The relations of the ratio of density to the ratio of vertical height of the two kinds of particles are calculated, which shows that the main factor of granular oscillation is not the “Brazil nut effect” or “reverse Brazile nut effect”. The granular temperature is calculated and found to be relevant to oscillations of mixture. When the temperature of the small particle is above a certain value, oscillations of granular mixture occur. According to hydromechanical equations proposed by Viridi et al., these equations are correspondly modified and may explain the relations between the period of oscillation and the ratio of granular density.

As one of the extremely rich polysaccharides in the world, chitin is also a material with excellent biocompatibility, biodegradable, green, non-toxic and harmless properties, so the new materials made of chitin are widely used in the food industry, biomedicine, health and safety and other fields. The development of new chitin materials has inhibited the use of traditional petroleum-based materials to some extent and improved the ecological environment. However, due to the defects of traditional extraction methods, the industrialization scale and commercialization of chitin are still in a bottleneck stage. This is due to the preparation of chitin new materials generally need to dissolve and extract it, and chitin has a high molecular weight, the existence of a large number of strong intermolecular hydrogen bonds makes it crystallinity high. At the same time, the structure of chitin is also relatively special due to its regular intermolecular arrangement, so chitin is difficult to melt and does not dissolve in water, alkaline solvents and most organic solvents.Therefore, in order to avoid the processing problems caused by chitin extraction, direct extraction and dissolved chitin extraction are introduced to prepare new materials, and proposed the development prospect of chitin.