Abstract: An epidemic forecasting model for policies of prevention, control and isolation is disclosed, including: establishing a SUEIR model; dividing, by the SUEIR model, population according to an ability of infection and a way of infection; classifying patients further into three states: unconfirmed, confirmed but not in isolation, and confirmed and in isolation; calculating a number of people in each state in the future by using the SUEIR model; and accumulating the number of people in the confirmed state to realize the forecasting of the number of confirmed cases. The disclosure not only accurately forecasts the number of confirmed cases, but also explains various policies of prevention and control.

Abstract: A construction method of a fine-grained infectious disease simulation model is disclosed. The construction method includes: obtaining a population movement flow between multiple target regions within a predetermined time period; dividing the predetermined time period into multiple time periods based on a time mode; dividing the multiple target regions into multiple spatial nodes based on a spatial mode; and constructing a simulation model according to the population movement flow, the multiple time periods, and the multiple spatial nodes. By the method, the dynamic modeling of the development of infectious diseases is completed; the sub model modeling under different time modes is completed; and the fine-grained modeling under different spatial modes is completed.

Abstract: The present invention provides a QFN packaging structure and QFN packaging method. The electromagnetic shielding layer as provided on the outer side of the QFN packaging structure by spacing at a certain interval from the leads may cooperate with the base island having the lug boss on the side edge, such that all surfaces of the chip can be electromagnetically shielded and protected while ensuring the insulation between the electromagnetic shielding layer and the leads.

Abstract: An epidemic forecasting model for policies of prevention, control and isolation is disclosed, including: establishing a SUEIR model; dividing, by the SUEIR model, population according to an ability of infection and a way of infection; classifying patients further into three states: unconfirmed, confirmed but not in isolation, and confirmed and in isolation; calculating a number of people in each state in the future by using the SUEIR model; and accumulating the number of people in the confirmed state to realize the forecasting of the number of confirmed cases. The disclosure not only accurately forecasts the number of confirmed cases, but also explains various policies of prevention and control.