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A data-driven energy ecan in the immediate vicinity of the 7 pair production tbreshold has been performed using the Beijing Spectrometer at the Beijing Electron-Positron Collider. Approximately 5 pb-' of data, distributed over 12 ecan points, have been collected. A previous maee value for the 7 lepton, obtained using only the ep final state, has been published. In this paper, the final BES result on the maes measurement is presented. The analysis is based on the combined data from the ee, ep, eh, VW, ph, and hh final states, where h denotes a charged ?(or K. A maximum likelihood fit to the r pair production cross section data yields the value rn, = 1776.96+~:~~!~:~~ MeV.

The paper summarizes research progress in ways to improve the load bearing capacity of composite motor cases. It especially sheds light on research progress in the selection of case materials, reinforcement technologies, experimental study and finite element analysis, layer sequence optimization, and hybrid fiber design for boosting the internal and external load bearing capacity of solid rocket motors’ composite cases.

Backgroud:COVID-19 was recognized a public health issue and SARS-CoV-2 was assumed to infect human ovary and cross the blood–testis barrier. Method:To explore the infection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients’ semen and follicular fluid and its potential clinical outcome. Ten female patients with an average age of 30.7±4.11years and eight male patients with an average age of 32.13±4.45 years diagnosed with COVID-19 and their spouses were negative to COVID-19 were included. Results: None of ten male and 8 female patients with COVID-19 affecting was absence of SARS-CoV-2 RNA in semen and follicular fluid. The sperm parameters, the rates of oocytes maturation, fertilization, cleavage and blastulation between the control and test group was not statistically significant (P>0.05),but the sperm quality, the oocyte maturation and fertilization, the blastulation showed a decline tendency in COVID-19 affected patients. Conclusion: COVID-19 affection may have an uncertian negative influence on the gamete quality and embryo development. Our new knowledge will help to evaluate the impact of COVID-19 on fertility in virus infected patients.