Investigation on the dynamic characteristic of occupant during the frontal collision between high-speed train and obstacle.

High-speed train may collide with many obstacles, which can cause serious occupant injury. This study aims to investigate the dynamic characteristic of occupant during the frontal collision between high-speed train and obstacle. The finite element method was used to establish the collision model between the head vehicle of the train and obstacle. The frontal collision simulation tests under three collision conditions were established. The dynamic characteristics of occupants under different collision speeds and collision angles were explored. According to the above research, the influences of collision angle and speed on occupant injuries were systematically studied, and the risk boundaries for Railway Group Standard GMRT2100: Rail Vehicle Structures and Passive Safety (GM/RT2100) and Abbreviated injury scale ≥ 3 (AIS 3 + ) injury risk ≤ 5 % were finally proposed. The results show that the occupant injuries increased with the increase of collision speed, and most of the injury values at the collision angle of 20° were the minimum. The risk boundary for AIS 3 + injury risk ≤ 5 % was higher than that for GM/RT2100. The findings in this study are helpful to understand the occupant injury mechanism during the frontal collision between high-speed train and obstacle.

Construction of Relationship Model between College Students' Psychological Status and Epidemic Situation Based on BP Neural Network.

In view of the impact of COVID-19 on the mental health of college students, this paper proposes a study on the relationship between psychological status and epidemic situation of university students based on BP neural network, so as to provide theoretical basis for universities to take targeted mental health education. This paper investigates the effects of COVID-19 on the psychological emotions of college students. According to the behavior and psychological characteristics of college students, the relevant investigation results are obtained through event monitoring, early warning, and usual performance, and a relationship model between college students' psychological status and epidemic situation based on BP neural network is constructed. This paper studies several factors through the relationship model and uses the principal component analysis method to analyze the impact of various factors on college students' psychology. According to the model prediction and result analysis, it concluded that the influence of COVID-19 should focus on improving the professional quality, physical quality, humanistic quality, and moral quality of university students, so as to improve the stability of colleges and universities in the event of public health emergencies. The model constructed in this paper can provide reference for carrying out mental health education and formulating effective intervention programs.

Crashworthiness analysis of a multi-layered bi-directionally corrugated steel plates structure.

This paper proposed a multi-layered bi-directionally corrugated plates structure (BCPS) for energy absorption. Quasi-static compression experiments and finite element method (FEM) were used to investigate the crushing performance of the multi-layered BCPS. The results showed that the multi-layered BCPS had very small initial peak crushing force, and the fluctuation of force was very small during the whole compression process. These characteristics made the multi-layered BCPS more advantageous in crashworthiness than traditional structures. It was also found that the crushing performance of the multi-layered BCPS was very sensitive to the geometrical parameters, such as the number of the cellular structures along the width nc, the number of plates nl, and the ratio of width of small square ws to width of big square wb of the pyramid cell η. Therefore, parameters optimization was carried out using the Multi-Objective Genetic Algorithm to find the best geometrical configuration of the structure. After optimization, the optimum parameters nc = 5, nl = 11 and η = 0.38 was obtained. The specific energy absorption increased by 143.76% compared with the initial configuration.

Synthesis and synergetic anti-tumor activity evaluation of dihydroartemisinin-organogermanium(IV) compound.

Dihydroartemisinin (DHA), a semi-synthetic derivative of the herb artemisinin, has shown commendable bioactivity. In this paper, a novel dihydroartemisinin-organogermanium (DHA-Ge) compound was synthesized, characterized and its potential anti-tumor activity was evaluated by various methods. MTT results demonstrated that DHA-Ge could effectively inhibit the proliferation of HepG2 cells and showed their dose-dependent properties. The IC50 value of inhibition effect on HepG2 cells of DHA-Ge was 10.23 µg/ml which was lower than 39.44 µg/ml of DHA. Flow cytometric results suggested that DHA-Ge could induce apoptosis of HepG2 cells and the apoptosis rate was 20.26% after 24h treatment with 56.8 µg/ml DHA-Ge concentration. Atomic force microscopy images showed that HepG2 cells were collapsed and the cell nucleus were fragmented after 24h treatment. All these results together showed that the DHA-Ge possessed desirable synergetic enhanced anti-tumor effects and could be developed as a suitable tumor therapeutic agent.

Synthesis and synergetic effects of chrysin-organogermanium (IV) complex as potential anti-oxidant.

Organogermanium(IV) (Ge) is considered to play an important role in the anti-oxidative activities of some Chinese medicines. Here, a new chrysin-organogermanium (Chry-Ge) complex was synthesized and investigated for its potential biological activities. The radicals-sensitive Ge-O bond was introduced to Chry-Ge complex to enhance bioactivities of organic Ge or Chry. Results showed that Chry-Ge complex possessed great anti-oxidative activities, showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated Chry-Ge complex inhibited ROS-dependent oxidative damage in cells. Moreover, the morphological and biophysical recoveries in oxidation-damaged cells induced by Chry-Ge complex were characterized by atomic force microscopy. All these results collectively suggested that Chry-Ge complex has synergetic effect for radicals scavenging and could be served as promising pharmacologically active agent against anti-oxidative treatment.