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According to the requirements of the 2022 China College Students Engineering Practice and Innovation Ability Competition, a self-propelled potential energy drive vehicle that can punch in designated trajectory points (simulating the Long March route) is designed and produced. The SolidWorks' Bezier curve is used to draw the fitted curve through a specific trajectory point. The fitting curve is further optimized and simulated by Matlab to obtain the cam profile that meets the design requirements. Combined the with laser dot fine-tuning mechanism, the SolidWorks reverse modeling method is used innovatively, the arc cam steering mechanism is designed, to improve the accuracy and repeatability of the car running trajectory. Finally, SoildWorks is used to establish a three-dimensional model of the carbon-free car and analyze its structure. The running results of the car show that the car walking trajectory has good repeatability and can punch all the specified trajectory points.

Objective To explore the relationship of cognitive flexibility with perceived stress and life satisfaction in new recruits, construct a mindfulness-based cognitive intervention program, and investigate the impact of this program on cognitive flexibility and life satisfaction in the participants. Methods Cluster sampling was applied to select new recruits from a unit, and 965 participants were surveyed with questionnaires. The assessment instruments included Chinese Perceived Stress Scale (CPSS), Cognitive Flexibility Inventory (CFI), and Satisfaction With Life Scale (SWLS). Among them, 61 new recruits were divided into a training group (n=31) and a control group (n=30). The training group received a mindfulness-based cognitive intervention for 6 weeks, and the control group only received mental health education every week. The training efficacy were evaluated with questionnaires and behavioral experiment (cued task-switching paradigm). Results ① Perceived stress was significantly negatively correlated with cognitive flexibility and life satisfaction (r=-0.78, P < 0.01; r=-0.64, P < 0.01), and cognitive flexibility and life satisfaction were positively correlated (r=0.59, P < 0.01); ② The mediating effect was observed in cognitive flexibility between recruits' perceived stress affecting life satisfaction, with a mediating effect size of -0.12, accounting for 29.27% of the total effect; ③ After intervention, there were significant differences between the 2 groups of new recruits in terms of cognitive flexibility, life satisfaction, accuracy and reaction time in the cued task-switching paradigm, with those of the training group obviously better than those of the control group (P < 0.05). The training group obtained notably improvements in above scores after intervention (P < 0.05), but no such changes were observed in the control group. Conclusion Mindfulness-based cognitive intervention can effectively improve cognitive flexibility and life satisfaction for new recruits.

Rainfall-runoff is the main source of pollution in the urban water environment. This study investigated the dynamic changes of soluble Nickel (Ni) and Arsenic (As) in the receiving water body after the rainfall and runoff of the Meishe River in Haikou. Field sampling and indoor analysis were used. Results revealed that the solid-liquid partitioning of Ni and As in the receiving water body is directly disturbed by the inflow of rainfall-runoff. The main source of the input is the suspended state, and the input of the dissolved state is smaller. The specific performance is as follows. Before the rainfall-runoff flows into the receiving water body, the ratio of soluble Ni and As to the total content reaches 55.67% and 94.77%, respectively. After the rainfall-runoff flows in, a series of dynamic changes of Ni and As occur in the receiving water body. The proportion of soluble Ni and As at the outlet decreases significantly and changes dramatically, reaching 20.97% and 76.92% of the total content, respectively. The proportion of soluble Ni and As in the downstream of the drainage outlet also decreases to a certain extent, reaching 47.23% and 88.38%, respectively. The data under different rainfall scenarios indicate that the long dry period, when the rainfall is less than 10 mm, is the main factor affecting the dynamic changes of soluble Ni and As. Furthermore, the long dry period, along with the peak time, and magnitude of the rain intensity are the major influencing factors of the response time and degree of soluble Ni and As to rainfall-runoff, when the rainfall amount ranges from 10-30 mm. The peak time of rainfall intensity is the main factor affecting the dynamic change of soluble Ni and As in the receiving waters when the rainfall amount is above 30 mm. The effects of rainfall-runoff on the soluble Ni and As in the receiving water are different. When the dry period is short and the maximum rainfall intensity is high, in receiving water, soluble As is less affected by rainfall-runoff, while soluble Ni is significantly affected.

In order to improve the method to design the linkage mechanism of three-roller guiding device installed at the exit of piercing mill,the mathematical model of the multi objective optimal design is established based on comprehensive consideration of the technical requirement,the operation condition and the transmission performance of the mechanism.The fully parameterized virtual prototyping model of mechanism is optimized by simulation to determine the design parameter in the ADAMS environment.Under the given constraints,the simulation results show that the comprehensive performance of the mechanism is significantly improved.

Image fusion currently plays an important role in the diagnosis of prostate cancer (PCa). Selecting and developing a good image fusion algorithm is the core task of achieving image fusion, which determines whether the fusion image obtained is of good quality and can meet the actual needs of clinical application. In recent years, it has become one of the research hotspots of medical image fusion. In order to make a comprehensive study on the methods of medical image fusion, this paper reviewed the relevant literature published at home and abroad in recent years. Image fusion technologies were classified, and image fusion algorithms were divided into traditional fusion algorithms and deep learning (DL) fusion algorithms. The principles and workflow of some algorithms were analyzed and compared, their advantages and disadvantages were summarized, and relevant medical image data sets were introduced. Finally, the future development trend of medical image fusion algorithm was prospected, and the development direction of medical image fusion technology for the diagnosis of prostate cancer and other major diseases was pointed out.

Ultrasound, serveing as an oscillating source, can induce cavitation in liquids; and the bubble produced in this process is a very promising kind of vector for gene delivery and drug target release, owing to its unique properties. This article involves the cavitation mechanism, the control over sonoporation, and the influence of ultrasound contrast agent. The status quo of research and the challenges encountered are discussed. This overview is devoted to providing a theoretical basis for clinical use of cavitating bubble vector.

Polyhydroxyalkanoates(PHAs) are polyesters synthesized by numerous bacteria in sludge as intracellular carbon and energy storage compounds under the condition of unbalance growth. Another important aspect of PHAs is thermoplastic polyester with the remarkable characteristics of biodegradability. In this paper, using sodium acetate, sodium propionate and sodium butyrate as the unique carbon source, 5.58%, 3.90% and 4.98% PHAs of dry sludge weight were obtained by assimilated sludge as PHAs synthesis strains in the anaerobic condition, and 12.32%, 9.55% and 11.35% PHAs of dry sludge weight were obtained in the anaerobic condition. It was shown that there were large quantities strains which could accumulate PHAs as granules in the cytoplasm of cells, and the yield of PHAs in the anaerobic process were higher than that in the aerobic process. The best result was that 12.32% PHAs of dry sludge weight was obtained in the best experiment condition, and the yield of the PHAs to substrate was 30.65%. The structures of PHAs were analyzed by 1HNMR spectrum, and the relationship of the structure of PHAs and the carbon source was explained.