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This paper first discussed the mathematical model of BeiDou/GPS combined pseudo-range point positioning. And then observational data of Beijing and Wuhan stations was used to compare BeiDou/GPS combined solution results with BeiDou and GPS single system solution results on the aspects of satellite visibility, PDOP value, positioning accuracy and usability in multiple simulative masking environment. The numerical results showed that compared with the pseudo-range point positioning of a single system, BeiDou/GPS combined positioning greatly increases the number of visible satellites and reduces the PDOP value. In addition, the combined system can effectively improve the positioning accuracy and the usability under poor observation conditions. [ABSTRACT FROM AUTHOR]

In order to explore the mechanism of soil reinforcement and slope protection by plant roots, in this paper, the mechanical characteristics of roots on soil stabilization were discussed from the meso angle, and using a CT triaxial apparatus developed at the Yangtze River Scientific Research, a series of unconsolidated-undrained CT real-time triaxial shear test of the non-rooted clay sample and two kinds of Broussonetia papyrifera-rooted clay samples with different root diameters were carried out. Through a quantitative analysis of CT scan data of three sections at the different strain for three kinds of samples, it was found that both the downward section of (mean CT number) ME-ε1 curve and the upward section of (the variance of CT number) SD-ε1 curve of the non-rooted soils had a greater changing amplitude than those of the rooted soils in three different scan layer sections. It indicated that the internal defects of the rooted soil grew more slowly and weakly, the initiation and propagation of internal cracks slower, and the roots resist cracks. This paper focused on the qualitative and quantitative analysis of CT scanning images of the height of a 7/16 cross section at the different strain for three kinds of soil samples. Using the program self-prepared in Matlab software, the CT scan images were binarized, and the statistical crack data of the scan layer section were obtained including the crack rate of cross section, the total crack size in the area near the root and beyond the root respectively, and the length and width of the maximum crack area. Through the comparative analysis of CT scan images evolution under pressure and the statistical crack data of them for the non-rooted soils and the rooted soils, the fundamental differences in destruction process of the soil and crack propagation between the non-rooted soil and the rooted soil were described, thus exposing the crack resistance and the bridging effect of roots. It was concluded that the mesomechanics mechanism of roots reinforcement is mainly the crack resistance and the bridging effect of root on the soil. [ABSTRACT FROM AUTHOR]

Objective To understand the working pressure source of obstetric nurses in Kunming through a sample survey study, so as to provide a reference for obstetric nurses to adjust self-psychology and for clinical managers to relieve working pressure on obstetric nurses. Methods We gave a sampling survey on 249 obstetric nurses in provincial, municipal and private hospitals, and used "Chinese nurse job stress scale" to collect the data for statistical analysis. Results Kunming obstetric nurses' working pressure mainly came from the workload and time allocation. The ten stressors with highest score of pressure were frequent highest score, too much work, low welfare benefits, too much useless paperwork, low social status, worry about mistakes at work, too high expectation of patients, too much non-nursing work, nursing work is not accepted by patients and their families, few nurses to work. Age, title and nature of the preparation had no effect on work stress. Public hospital nurses' working pressure was significantly greater than private hospitals. Conclusion Working pressure sources of obstetric nurses in Kunming are too much night shift, too much work, welfare benefits useless paperwork, social status, mistakes at work, patients expectation work is not accepted and staffing Hospital management and nursing managers should deploy rationally human resources on obstetric area, reasonable scheduling. [ABSTRACT FROM AUTHOR]

This paper used numerical methods to investigate the flow field around wind turbine airfoil S809 and the airfoil with micro tab at 95% chord at the pressure side neat the trailing edge. The adaptive SST turbulence model was chosen to analyze the detailed flow field of the two airfoils under different angles of attack. The effect of the micro tab was brought out, and then the lift arising mechanism of the micro tab was presented. The results showed that the lift arising mechanism of the micro tab lied on the change of Kutta condition of the airfoil. The micro tab made the stagnation point move to the end of the micro tab, which made the aerodynamic profile and circulation increased. Meanwhile, the micro tab only availed at the normal working condition. [ABSTRACT FROM AUTHOR]