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Background: With the increase in the speed and capacity of freight trains, the safety, energy efficiency and intelligent operation of train operation have become increasingly important. Automatic freight trains operation can replace manual operation with automated control systems, which can guarantee the safety of train operation, and improve operational efficiency and reduce operational energy consumption. Objective: Solve the problem of tracking accuracy and stability deterioration caused by multi-information of freight train. Methods: Global navigation satellite system, inertial navigation system and speed measuring motor are selected to construct a speed fusion measurement model by using loosely coupled integrated navigation and improved entropy weight method. Calculate the information quantity of performance index and control quantity in preview control, get the controlled quantity of information fusion optimal preview control. Results: The average tracking error of the multi-source information fusion preview controller is 0.038m/s, which is 49% lower than that of the control experiment. Conclusion: Multi-source information fusion preview controller can effectively reduce the tracking error of freight train speed tracking system and improve the accuracy of automatic freight trains operation. more...

Nitrocellulose membrane (NCM) can produce hydroxyl radicals under illumination, which promotes the oxidative degradation of organic pollutants. In this paper, NCM was used to oxidize bisphenol A (BPA) under simulated sunlight. The effects of pH, temperature, light intensity, anion and cation on the degradation of BPA were analyzed. The photodegradation process of BPA was discussed. The optimal photolysis rate was 0.031 min−1 when the temperature was 30°C, the light intensity was 2.67 × 104 Lux, and the pH value was 9.0. The alkaline environment, temperature and light intensity can promote the photodegradation of BPA. Except for nitrate ions, anions and cations can inhibit the photodegradation of BPA. Compared with cations, anions have a greater inhibitory effect on BPA degradation. The degradation products of BPA by NCM were analyzed by gas chromatographic/mass. This study may provide useful information for the BPA degradation by NCM in complex water samples. more...

We report on the initial results of seeing measurements at the Antarctic Taishan Station (ATS) using a differential image motion monitor observed in the visible at a height of 2.5 m above the snow surface, during the site-testing experiments carried out on 2014 January 13 and 15. The median seeing was found to be 0.73 arcsec and the 25th and 75th percentiles of the seeing cumulative distribution were 0.59 and 0.87 arcsec, respectively, with a minimum of ∼0.5 arcsec at ∼16:00–19:00 local time (UTC + 5). Such a seeing minimum has a good temporal association with the refractive index structure constant ($C_n^2$) minimum simultaneously observed at ATS. Interestingly, both temporal windows of $C_n^2$ and seeing minimum coincide with those of minimum temperature gradients ($\rm \sim 0\,^{\circ }C\,m^{-1}$), we had more than one month of continuous measurements of Cn2 and temperature gradients between 2013 December 30 and 2014 February 10. This suggests that high-quality seeing windows might be opened at ATS with the potential for astronomical activities, especially for solar observations. more...