Solar adaptive optics systems for the New Vacuum Solar Telescope at the Fuxian Lake Solar Observatory

Adaptive optics(AO)is essential for high-quality ground-based observations with large telescopes because it counters the impact of wavefront aberrations caused by atmospheric turbulence.The new vacuum solar telescope(NVST)is one of the most important high-resolution solar observation instruments in the world.Three sets of solar adaptive optics systems have been developed and installed on this telescope:conventional adaptive optics,ground layer adaptive optics,and multi-conjugate adaptive optics.These have been in operation from 2018 to 2023.This paper details the development and application of solar adaptive optics on the NVST and discusses the newest instrumentation.

The clinical efficacy of percutaneous ethanol-lipiodol injection(PEI)combined with high-intensity focused ultrasound(HIFU)for small hepatocellularcarcinoma in special or high-risk locations

Objective The objective of this study was to explore the short-term effects and postoperative complications of ultrasound-guided percutaneous ethanol-lipiodol injection(PEI)combined with high-intensity focused ultrasound(HIFU)for the treatment of small hepatocellular carcinoma in a special or high-risk location.Methods Forty patients with small liver cancer in a special or high-risk location were randomly divided into two groups:20 patients were treated with PEI combined with HIFU(P+H group),and 20 patients were treated with HIFU alone(H group).There were no significant differences in average age,liver function,tumor location,tumor number,or tumor size between the two groups(P>0.05).Results Significant differences were observed in ablation parameters between the two groups(P<0.05).Under the same power,ablation rates of the P+H group were significantly higher than those in the H group,and postoperative complications in the P+H group were significantly lower than those in the H group(P<0.05).Conclusion The combination of PEI and HIFU has better clinical value than HIFU alone for small-cell liver cancer in special or high-risk locations.

Ground-layer adaptive optics for the New Vacuum Solar Telescope:Instrument description and first results

Ground-layer adaptive optics(GLAO)has shown its potential for use in solar observation owing to its wide field-of-view(FOV)correction.A high-order GLAO system that consists of a multiple direction Shack-Hartmann wavefront sensor(WFS),a realtime controller with a multi-CPU processor,and a 151-element deformable mirror was developed for the 1-m New Vacuum Solar Telescope at Yunnan Observatories,Chinese Academy of Sciences.A hexagonal microlens with 9×8 subapertures is employed in the WFS.The detection FOV is 42′′×37′′,in which 9(3×3)guide regions are extracted for multiple direction wavefront sensing with a frame rate of up to 2200 Hz.To our knowledge,this is the first professional solar GLAO system used as a regularly operating instrument for scientific observations.Its installation and adjustment were performed in the summer of 2021.In this article,a detailed account of the GLAO system and its first light results and a comprehensive analysis of the performance of the GLAO system are provided.The results show that this system can effectively improve the imaging quality after compensating for the wavefront aberration due to ground-layer turbulence.