Abstract: A method for preparing hydrogen from ammonia by using pressure swing adsorption (PSA) is provided. The method for preparing hydrogen from ammonia, of the present invention, comprises the steps of: generating hydrogen and nitrogen from ammonia gas through a high-temperature reaction by using a catalyst; performing purification by selectively adsorbing unreacted ammonia gas from a gas containing unreacted ammonia and low-purity hydrogen and nitrogen, which are supplied through the high-temperature reaction and cooled; and performing purification by separating high-purity hydrogen from the gas consisting of low-purity hydrogen and nitrogen, wherein purification is carried out by using a carbon molecular sieve (CMS) adsorbent so as to desorb the unreacted ammonia gas through PSA.

Abstract: A unidirectionally operating laser apparatus using a semi-monolithic ring cavity having a compact structure capable of achieving a high frequency stability and a high-speed laser frequency tuning and modulation. The laser apparatus includes a laser active medium having a curved surface exhibiting an anti-reflection characteristic for a pump laser beam from a pump laser incident thereon while exhibiting a high reflection characteristic for an oscillating laser beam, a planar surface exhibiting an anti-reflection characteristic for the oscillating laser beam, and an optically-active polarization rotator attached to one side portion of the planar surface. The laser apparatus also includes an output mirror separated from the laser active medium, the output mirror having a curved surface with a coating exhibiting a higher reflectance coefficient for S-polarized beams than that for P-polarized beams, and a piezo-electric transducer.