Search

The telescope is the core device for space gravitational wave detection. It is responsible for receiving signal light and emitting outgoing light simultaneously. When the high-energy outgoing laser passes through the telescope, it would produce stray light, which would interfere with the phase measurement and generate phase noise. Therefore, it is necessary to analyze and suppress the stray light of the telescope. In this paper, the requirement of point source transmittance (PST) of the Taiji telescope is obtained through theoretical derivation, which is less than 4×10−10. Through a complete analysis of stray light, we determined that the M4 was the largest source of stray light under the condition that the roughness of each optical surface is equal, which accounted for 67.22%. We also determined the most lenient requirements for surface roughness σλ, and found that when σλ of the M1, M2, M3, and M4 were 20 Å, 4 Å, 1 Å, and 1 Å, respectively, the PST was 3.89×10−10, which met the PST requirement. Next, we calculated the effect of particulate contamination on the PST, and based on the results of our analysis, we determined that the cleanliness level of the testing and storage environment of the Taiji telescope was better than 300. Finally, we evaluated the changes in the PST caused by the damage of micrometeoroids, and the analysis results showed that the stray light level would not change significantly during the service period of the Taiji Telescope.

Background: Since December, 2019, Wuhan, China, has experienced an outbreak of 2019 novel coronavirus pneumonia (COVID-19). Epidemiological and clinical characteristics of patients with COVID-19 have been reported. A few studies reported clinical course of illness of median 22 days, including viral shedding of median 20 days, but there are several cases with a longer time of viral shedding.Methods: In this retrospective, single-centre cohort study, we included four cases with a longer course of illness of more than 40 days with laboratory-confirmed COVID-19 from Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or still in hospital by March 15, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records. We describe the epidemiological and clinical characteristics and the course of viral shedding.Results: Of the four patients, one was discharged and the other three were still in hospital. Two patients had comorbidity, one with hypertension and one with diabetes. We found smoking is not an independent risk factor . And D-Dimer maybe relates to severity of illness but not course of illness. Decreased lymphocyte count had a slow recovery process in three patients. elevated eosinophils count in all patients suggest maybe elevated eosinophils count was a reason of long course. Nucleic acid detection suggests maybe more sampling sites represent more virus replication sites and longer course illness.Conclusion: In this study we find some non-critical severe relatively young patients with sustained non-negative with nucleic acid detection whose character is different from former studies described. Of course, it needs much more cases to further study. It’s hoped to provide strategy of isolation of infected patients and optimal antiviral interventions in the future.