The super dual auroral radar network (SuperDARN) is an important tool in the remote sensing of ionospheric potential convection in middle and high latitudes, and also a major source of elevation data detection. A reliable elevation angle helps estimate the propagation paths of high-frequency radio signals between scattering spots and radars, which is crucial for determining high-frequency radar target geolocation. The SuperDARN radar uses interferometry to estimate the elevation of the returned signal. However, elevation data are still underutilized owing to the difficulties of phase difference calibration induced by the propagation time delay between two arrays. This paper statistically analyzes the distribution features of the group range-elevation angle and group range-virtual height before and after calibration using elevation data from the ground backscatter echoes of the Zhongshan SuperDARN radar, calculating the root mean square error (RMSE) of the virtual height; the results show that the RMSE after calibration is mostly reduced to within 54% of that before calibration. Furthermore, we validate the calibration factor based on the primary phase data. The data from 2013 to 2015 indicate that this technique can be efficiently used to estimate the daily calibration factor. Finally, we present the statistical distribution of the calibration factor, which provides technical support for the calibration of elevation data in the future.

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Triblock copolymers are playing important roles in nanomaterial synthesis, and the nanomaterial forming mechanisms need to be studied in detail. In situ liquid cell transmission electron microscopy (TEM) is a powerful tool for real time observation of the dynamic growth behavior of nanomaterials in liquid with high resolution, and could be used for the above task. Here we report the observation of the growth and self-assembly of Pt nanoclusters with the aid of an ethylene oxide-propylene oxide-ethylene oxide triblock copolymer (PEO-PPO-PEO) F127 using in situ liquid cell TEM, with the nanocluster growth and formation procedures being tracked. Nano objects were seen to appear, drift and rotate with time, and then form into certain shaped nanoclusters under the electron beam irradiation. Further interestingly, in the thicker liquid layer region, the nanoclusters appeared to be fluffy, with average size keeping increase with time, while in the thinner region, the clusters were thinner, and got densified with time. The difference in precursor availability due to liquid layer thickness and charging effects is attributed to such a phenomenon.

Background and Purpose— In the Asymptomatic Carotid Surgery Trial-1 (ACST-1), 3120 patients with tight asymptomatic carotid stenosis were randomly assigned to medical treatment alone or to carotid endarterectomy and appropriate medication. Successful carotid endarterectomy significantly reduced 10-year stroke risk in younger patients. This study was undertaken to determine the risk of new occlusion and stroke during trial follow-up. Methods— Patients with contralateral occlusion at trial entry (n=276) or incomplete duplex follow-up (n=137) were excluded. Risk of occlusion and stroke in patients with occlusion was estimated by Kaplan–Meier analysis. Cox proportional hazard regression models were used to determine risk factors for developing new occlusion and stroke. Results— Median follow-up in 2707 patients was 80.0 months (interquartile range, 52.0–115.0). New occlusions occurred in 197 patients (1.1% per annum) but were more likely to occur in arteries with tight stenosis and in unoperated patients. Overall risk of stroke was 7.6% (95% confidence interval [CI], 6.6–8.7) and 15.5% (95% CI, 13.6–17.4) at 5 and 10 years, respectively; for patients with new occlusion, this significantly increased to 17.0% (95% CI, 11.6–22.4) and 20.8% (95% CI, 14.1–26.2), respectively ( P <0.001). Stroke was significantly more likely to occur in patients developing occlusion (hazard ratio, 1.78; 95% CI, 1.26–2.51) irrespective of allocated treatment. Conclusions— New occlusions were uncommon after carotid endarterectomy in ACST-1. During long-term follow-up, occlusion and stroke were commoner among patients with ≥70% stenosis, most of whom had not undergone carotid endarterectomy. Occlusion was an independent prognostic risk factor for occurrence of stroke.

This article introduced carries on the fuzzy controller’s design process using the VHDL language, The degree of membership function's memory used the partition memory law to the fuzzy control process, the design method has been simple, raised the operating speed and the precision. with the advantages of fuzzy control theory and the limitations which the PID control algorithm for the traditional application in the modern agriculture, meanwhile designed the fuzzy self-turning PID control algorithm, and then studied and analysis this algorithm deeply, and has given the corresponding VHDL code.