Suppose the economy is in a recession and the central bank decides to use traditional open market operations to stimulate the economy.What will it do, and what will the new yield curve look like after it has done this?

Suppose the central bank thinks the long end of the yield curve hasn't changed enough so it decides to use quantitative easing.What is quantitative easing?What will the yield curve look like after the central bank has done this?(3 yield curves on same diagram)