A self-retracting step assembly is attached to a swimming platform provided on the rear of the hull of a boat. The composition has improved storage stability, filling properties, adhesion and coating uniformity sufficient to form a sacrificial film which is dissolvable in a stripping solution. It is proposed to dynamically adjust the at least one bearer service provided through the heterogeneous wireless network according to an operational context of a mobile endpoint. The fluid from the supply chamber flows into the fluid feed chamber and the fluid feed chamber is radially open towards the outflow openings across the entire circumference of each of the outflow openings, so as to direct an annular fluid stream onto the hot gas. The method includes a step of forming an inorganic micro-powder layer in which an inorganic micro-powder layer is formed on the base; and a step for forming thee partition wall in which the partition wall is formed by irradiating the inorganic micro-powder layer on the base with laser light so as to melt the inorganic micro-powder layer and form the partition wall.