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ObjectivesThe wake of wind turbine affects the overall power output of wind farm. The analysis of wake characteristics is the key to study the influence of yaw control on wake. Therefore, the effects of different yaw angles of the upstream wind turbine on the wake characteristics (such as turbulence integral scale, power spectral density, etc. ) and the eddy current motion in the wake were studied, to understand the wake characteristics of the wind turbine under yaw conditions.MethodsThe wind tunnel was used to study the evolution law of the downstream wake of the wind turbine at 0°, 15° and 30° yaw angles. The turbulence integral scale and power spectral density were used to describe the wake characteristics, and the correlation between different feature points was analyzed.ResultsThe yaw angle has little effect on the horizontal wake, and the turbulence integral scale does not change much. The turbulent integral scale in the vertical direction has large fluctuations at different yaw angles. Through the analysis of the power spectral density, the contribution of eddy current motion to the turbulent kinetic energy of the wake is further quantified. The incoming current at 0° yaw is less disturbed by the rotation of the wind turbine than that at 15°. However, the increase of yaw angle does not always lead to an increase in the damage degree of wind turbines to the incoming current, and the decoupling effect on the incoming vortex structure at 30° is smaller than that at 15°.ConclusionsThere is a significant difference in the influence of yaw angle on the horizontal and vertical directions of wind turbine wake. The power spectral density analysis provides a quantitative basis for understanding the contribution of eddy current motion to the turbulent kinetic energy of the wake, which is helpful for in-depth study of the energy transfer and flow mechanism in the wake. There is not a simple positive correlation between the yaw angle and the disturbance and decoupling of the wind turbine on the incoming stream, which provides a reference for the optimal operation of the wind turbine and the layout of the wind farm.

［Objective］The urban rail transit video surveillance system provides a large amount of intuitive, real-time raw visual materials for rail transit operation and safety management. Utilizing these video materials to develop smart vision products and enhance management level and efficiency is a current application trend in smart vision. Therefore, it is necessary to study the construction plan for Shanghai rail transit SVL (smart vision laboratory). ［Method］The construction goal and plan for Shanghai SVL are introduced. Key indicators and evaluation methods for smart vision products, the test/evaluation platform and the testing business process of Shanghai SVL are also presented. ［Result & Conclusion］Establishing the SVL can achieve effective management of the application scenarios of smart vision products, form standardized technical test/evaluation, and provide a foundation for the incubation of smart vision products suitable for urban rail transit scenarios.

Objective In order to deal with the potential security threats caused by the complex connections between various subsystems in urban rail transit system, China Urban Rail Transit Association proposes that physical security isolation should be implemented between the safety production network and the external service network. Under the existing transmission method, problems such as packet loss and bit error often occur during one-way data transmission, and new methods need to be sought to improve the reliability of one-way data transmission in urban rail transit. Method The transmission principle and existing problems of the one-way security isolation system, as well as the proxy and session configuration in the one-way security gateway are described. The judgment methods of three types of transmission anomalies (proxy order disorder, session order confusion and transmission timeout) are analyzed. A data transmission method based on information backup is proposed, and the header format of backup information is built. The technical process of checking transmission anomalies by the data transmission method based on information backup technology is formulated, which is verified by experiments. Result & Conclusion This method can effectively solve the problem of low reliability of one-way data transmission of urban rail transit.

Objective Prevention and protection of foreign objects intrusion into railway becomes a hot research topic, and the division of intrusion areas requires detection of the track location. In order to determine the track location in the image, a method based on improved Mask R-CNN (Mask region convolutional neural network) combined with mathematical model is proposed to identify and extract the railway track. Method Firstly, Mask R-CNN is optimized and added with attention mechanism, and transfer learning is introduced into the above method to improve the model′s generalization ability. Then the optimized model is used to identify and segment the track, extracting the segmentation data and fitting with the corresponding mathematical expression to realize the identification and extraction of the track. The track in the image is divided into four categories and labeled with the Labelme labeling software, forming a training set and a test set. The training set is used to train the optimized model, and the test set to evaluate the detection results of the optimized model. Result & Conclusion The research results show that compared with other segmenting models and the original model, the proposed method performs well under the same training intensity, reaching 97.5% of the accuracy rate in track type determination, and basically above 80% in track segmentation. Tests show that the proposed method improves the general applicability of the detection by using the good performance of neural network, and can accurately determine the track type and segment the track.

Abstract Objectives The purpose of this study was to explore the effects of inhalational anaesthetics on the male reproductive system in neonatal rats. Methods Postnatal day 6 (P6) male rat pups were assigned to 2 groups of 40 rats each. The control group did not receive anaesthesia, and the test group was exposed to air containing 3% sevoflurane in a chamber. After sevoflurane exposure, the effects on the male reproductive system in neonatal rats exposed to inhalational anaesthetics were tested. The rats were maintained to P60. The fertility, sperm and spermatid count, sperm motility, organ weights and histological changes in rats were determined. Results Compared with those of the control group, the sperm count and motility of the sevoflurane group were significantly decreased (p < 0.05), and there was also a decrease in the number of foetal rats from the sevoflurane group (p < 0.05). Furthermore, the arrangement of the seminiferous tubule was regular in the control group, whereas the arrangement of the seminiferous tubule was distorted and the spermatocytes were detached and irregularly lined in the sevoflurane group. TUNEL analysis showed that the number of apoptotic cells in the testes of the sevoflurane group was significantly increased (p < 0.05). SOD and MDA analyses showed that SOD was decreased, while MDA expression was increased. Conclusions These data indicated that young rats suffered as a result of inhalation of the anaesthetic sevoflurane and had reduced reproductive system function during adolescence in males. These studies are useful as a foundation for clinical studies.

Objective To investigate the phototherapy effect of multifunctional nanometer cerium oxide quantum dot (HACQDs-Ce6) on HepG2 cells. Methods The dissolved oxygen analyzer was used to detect the catalytic oxygen production capacity of HACQDs-Ce6. CCK-8 method, scratch test and Calcein AM/PI staining were used to analyze the effects of HACQDs-Ce6 on the proliferation, migration and apoptosis of HepG2 cells. The recombinant mouse macrophage-granulocyte colony stimulating factor (rm GM-CSF) and recombinant mouse interleukin-4 (rm IL-4) were used to induce the differentiation of mouse bone marrow precursor cells into dendritic cells (DC) in vitro to investigate the effect of HACQDs-Ce6 on DC cells. Results HACQDs-Ce6 had catalytic oxygen production capacity. The proliferation activity of cells in the laser group was significantly lower than that in the dark group when the concentration of HACQDs-Ce6 was greater than 0.125 μg/ml (P=0.018). The migration ability of HepG2 cells in HACQDs-Ce6 group was significantly lower than that in the PBS group (P < 0.01). HACQDs-Ce6 almost had no effect on HFF-1/L wnt-3A and DC cells. Calcein AM/PI staining showed that the combined action of HACQDs-Ce6 and PDT killed almost all the HepG2 cells. Conclusion The phototherapy effect of HACQDs-Ce6 on HepG2 cells is obvious, with no damage to HFF-1/L wnt-3A/DC cells.

The traditional turnout fault detection method not only leads to consume a lot of manpower, material resources and financial resources, but also relies on manual experience. With the rapid development of artificial intelligence, designing an intelligent diagnostic system to diagnose the turnout is a key problem. In this paper, an intelligent detection system is proposed, which contains data preprocessing, feature extraction, switch intelligent classifier and more suitable evaluation criterion design. It is simulated by MATLAB, the experimental results on Guangzhou village station switch current data of model W1902# and model W1904# shows that the current intelligent detection method not only has the ability of self-learning, but also can be detected efficiently in the complex changes of the environment, and the recognition time is only 0.04 s, which meets the real-time requirement of railway.

Although Type A personality traits have been confirmed to be more frequently engaged in risky driving behaviours, the existing research on the decision-making of queue-jumping behaviours has not considered this personality trait. This study aimed to explore the decision-making processes of the subject driver's queue-jumping and the follower vehicle driver's yielding behaviours with Type A and Type B personalities. First, the decision-making utility variables for both players were selected, and a payoff matrix considering utility variable weights was constructed. Next, a decision-making utility evaluation questionnaire was designed, and this questionnaire and the existing Type A behaviour pattern scale were investigated simultaneously. Then, the weight coefficients of the decision-making utility variables were calculated; the replicated dynamic equations of four game combinations were constructed and the local stability principle of a dynamic system was used to determine the evolutionarily stable strategy for each game combination. Finally, the evolutionary process in which subject vehicle drivers select jumping the queue strategy and follower vehicle drivers select giving way strategy was simulated using MATLAB software based on empirical data to verify the validity of the constructed evolutionary game model. The results indicated some differences in the weight coefficients of decision utility variables between Type A and Type B personalities. The constructed game model can effectively reflect the decision-making processes of subject and follower vehicle drivers of different personality types. The dynamic evolution processes of strategy selection were different for the four game combinations. This study revealed the evolutionary game process between subject and follower vehicle drivers, laying a theoretical foundation for traffic management departments to manage queue-jumping behaviours., Author(s): Liping Yang (corresponding author) [1]; Mengmeng Zhang [1]; Lidong Zhang [1]; Qinghai Lin [1] 1. Introduction Recently, traffic congestion has become a common problem faced in various cities. In [...]