Abstract: A solid electrolyte comprises a microporous film having high crystallizability and excellent solvent resistance. The microporous film is controlled by a wet phase inversion method to a porosity of 50% or greater and a pore diameter of 0.02 &mgr;m to 1 &mgr;m inclusive. The solid electrolyte may be used to construct an electrochemical device, a lithium ion secondary battery and an electric double-layer capacitor.

Abstract: A filter apparatus comprises a housing having a liquid entrance, a liquid exit, and two tubes protruding from a wall of the housing into an inner space of the housing. The tubes have openings which face each other and have at least one perforation or side opening on their walls, one of the liquid entrance and the liquid exit being connected to one of the tubes. The detachable filter cartridge comprises an outer perforated cylinder, an inner non-perforated cylinder, the outer cylinder being connected to the inner cylinder in coaxial relationship such that a respective end space for receiving a liquid is formed inside each end of the outer cylinder. A bundle of porous hollow fibers is connected between the outer cylinder and the inner cylinder such that openings at both opposite ends of the hollow fibers open to allow passage of liquid from one end space for receiving liquid to another end space via the hollow fibers.

Abstract: Test composition and test stick for detection of chloride ion in cow's milk, which composition comprises a protected silver chromate colloidal substance, a surface active agent and a buffer agent having a pH value ranging from 2 to 7, and which test stick comprises a carrier, protected silver chromate colloidal substance, a surface active agent and a buffer agent having a pH value ranging from 2 to 7; and a method for producing the test stick.