Abstract The COVID-19 pandemic forced governments globally to impose lockdown measures and mobility restrictions to curb the transmission of the virus.As economies slowly reopen, governments face a trade-off between implementing economic recovery and health policy measures to control the thigh-strapon spread of the virus and to ensure it will not o
With a fiber pigtailed electro-optic modulator as the active Q-switch, mode-hopping-free single-longitudinal-mode pulses are generated by a ring cavity fiber laser based on the injection seeding technique.The experimental results show that the single-longitudinal-mode oscillating properties of the laser may be determined by the power and the center
To deal with train delays in large high-speed railway stations, a multi-objective mixed-integer nonlinear programming (MO-MINLP) optimization model was proposed.The model used the arrival time, departure time, track occupation, and route selection as the decision variables, and fully considered the station ORGANIC SHEA BUTTER infrastructure layout,