A window blind comprising a head rail, a bottom rail and a window covering extending between and operatively connected to the head rail and bottom rail. Particularly, the present invention provides methods and apparatus for non-contact temperature measurement for temperature below 500\xb0 C. The properties of these materials are chosen to optimize the interfaces on each side of the graded layer. A semiconductor device of logic-memory can be manufactured by a reduced number of manufacture processes while the transistor characteristics are stabilized and the fine patterns in the memory cell are ensured. The flow de-swirling section straightens the flow of fluid.