  The transition from normal state to superconductive state is a condensation
(Bose-Einstein condensation) process. As an example of Bose-Einstein
condensation, the condensation process of superconductivity is investigated in
detail. The basic unit of superconductivity is condensation circuit, which
should contain 4m+2 (m=1,2,...) electrons (holes). The perfect explanation for
no resistance and complete diamagnetism are given by using condensation
circuit. The quantum mechanics equation of superconductive state is
constructed, and energy level equation of superconductive quantum state is
given. The later equation has simple form (I is the unit matrix, A is the
adjacent matrix), with deep topological meanings. The phase transition from
normal state to superconductive state is irreversible. The irreversible process
is analyzed and discussed in detail. The temperature region of superconductive
state is calculated. The simplest structure of superconductor circuit is a
condensation circuit which is composed of a series of 3-4-element-circuits
(called lantern series structure). It is theoretically proved that the room
temperature superconductivity can be realized by using polylayer oxide
structure. The experimental frame of room temperature superconductivity is
suggested.
