Research on Covid-19 Pandemic and Social Security

Public health security is one of the important areas of social security. When the author drew up this thesis, the novel coronavirus pneumonia broke out in the Wuhan area, wreaking havoc on the entire land of China. Macroscopically speaking, the damage caused by the epidemic situation to social security is not only in public health, but also has a profound impact on public opinion, economic production and so on. In this paper, the author will analyze the damage on social security caused by the Covid-19 pandemic in three aspects: physical damage, social economic loss, and public opinion turbulence, furthermore, discussing its countermeasures

Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker

Due to its unique electronic property and the Pauli Blocking Principle, atomic layer graphene possesses wavelength-independent ultrafast saturable absorption, which can be exploited for the ultrafast photonics application. Through chemical functionalization, a graphene-polymer nanocomposite membrane was fabricated and firstly used to mode lock a fiber laser. Stable mode locked solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength have been directly generated from the laser. We show that graphene-polymer nanocomposites could be an attractive saturable absorber for high power fiber laser mode locking.Comment: Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker. Applied Physics Letters, Accepte

Graphene mode locked, wavelength-tunable, dissipative soliton fiber laser

Atomic layer graphene possesses wavelength-insensitive ultrafast saturable absorption, which can be exploited as a full-band mode locker. Taking advantage of the wide band saturable absorption of the graphene, we demonstrate experimentally that wide range (1570 nm - 1600nm) continuous wavelength tunable dissipative solitons could be formed in an erbium doped fiber laser mode locked with few layer graphene