摘要:
Disclosed herein is a method of purging a fuel cell, by which water present in fuel cell stacks is discharged outside the fuel cell stacks together with gas by opening and closing a purge valve, including: conducting a short-period purge several times using the purge valve; and conducting a long-period purge once using the purge valve, wherein the short-period purge and the long-period purge are repeatedly conducted. The method of purging a fuel cell is advantageous in that the short-period purge is conducted several times using a purge valve and then the long-period purge is conducted once, and these short-period purges and the long-period purge are repeatedly conducted, so that the problems occurring when only a short-period purge or only a long-period purge is conducted can be solved, with the result that the efficiency and performance of the fuel cell are improved and the fuel cell can be stably operated.
摘要:
A water-repellent glass having a durable and abrasion-resistant silica layer is prepared by a process containing the following steps: (a) preparing a silica solution by subjecting a metal alkoxide-based silane compound to a two step aging process wherein the two step aging process is proceeded either by conducting a first aging step under a basic condition and a second aging step under an acidic condition or vice versa, (b) applying the resulting silica composition onto the surface of a glass substrate, (c) subjecting the glass substrate coated with the silica composition to a thermal treatment, and (d) coating the resulting coarse silica layer with a water-repellent layer.
摘要:
A glass substrate is provided with a durable and abrasion-resistant water-repellent surface, by coating a surface of the substrate with a silica solution which has been subjected to a two-step aging process, respectively in the presence of basic and acidic catalysts, which is then thermally treated to provide a coarse-surfaced silica layer including fine crystalline silica particles, which is then coated with a water-repellent layer made of fluoroalkylsilane.