University of California

The United States of America as Represented by the Department of Energy

Raymond M Brusasco

Bernardino M Penetrante

Bernard T Merritt

George E Vogtlin

Lloyd A Hackel

Lawrence W Hrubesh

Alan K Burnham

Mark Kozlowski

Michael D Feit

Walter Grundler

Paul J Wegner

George K Governo

John E Peterson

Stephen M Maricle

James A Butler

The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

Reduction of damage initiation density in fused silica optics via UV laser conditioning

A high-surface-area (greater than 600 m2/g), large-pore (pore size diameter greater than 6.5 angstroms), basic zeolite having a structure such as an alkali metal cation-exchanged Y-zeolite is employed to convert NO contained in an oxygen-rich engine exhaust to N and O . Preferably, the invention relates to a two-stage method and apparatus for NO reduction in an oxygen-rich engine exhaust such as diesel engine exhaust that includes a plasma oxidative stage and a selective reduction stage. The first stage employs a non-thermal plasma treatment of NO gases in an oxygen-rich exhaust and is intended to convert NO to NO in the presence of O and added hydrocarbons. The second stage employs a lean-NO catalyst including the basic zeolite at relatively low temperatures to convert such NO to environmentally benign gases that include N , CO , and H O.

Highly-basic large-pore zeolite catalysts for NOx reduction at low temperatures

A optic is produced for operation at the fundamental Nd:YAG laser wavelength of 1.06 micrometers through the tripled Nd:YAG laser wavelength of 355 nanometers by the method of reducing or eliminating the growth of laser damage sites in the optics by processing the optics to stop damage in the optics from growing to a predetermined critical size. A system is provided of mitigating the growth of laser-induced damage in optics by virtue of very localized removal of glass and absorbing material.

CO2 laser and plasma microjet process for improving laser optics

The present invention provides a system that mitigates the growth of surface damage in an optic. Damage to the optic is minimally initiated. In an embodiment of the invention, damage sites in the optic are initiated, located, and then treated to stop the growth of the damage sites. The step of initiating damage sites in the optic includes a scan of the optic using a laser to initiate defects. The exact positions of the initiated sites are identified. A mitigation process is performed that locally or globally removes the cause of subsequent growth of the damaged sites.

Method for producing damage resistant optics

A two-stage method for NO reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO gases in an oxygen-rich exhaust and is intended to convert NO to NO in the presence of O and hydrocarbons. The second stage employs a lean NO trap to convert such NO to environmentally benign gases that include N , CO , and H O. By preconverting NO to NO in the first stage with a plasma, the efficiency of the second stage for NO reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO in the presence of O and hydrocarbons, such as propene. A flow of such hydrocarbons (C H ) is input from usually a second pipe into at least a portion of the first chamber. The NO from the plasma treatment proceeds to a storage reduction catalyst (lean NO trap) that converts NO to N , CO , and H O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO are simultaneously reduced while passing through the lean-NO trap catalyst. The method allows for enhanced NO reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Plasma-assisted catalytic storage reduction system

Hydrocarbon co-reductants, such as diesel fuel, are added by pulsed injection to internal combustion engine exhaust to reduce exhaust NO,to N,in the presence of a catalyst. Exhaust NO,reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbon co-reductants. By means of pulsing the hydrocarbon flow, the amount of pulsed hydrocarbon vapor (itself a pollutant) can be minimized relative to the amount of NO,species removed.

Nox reduction system utilizing pulsed hydrocarbon injection

A non-catalytic two-stage process for removal of NO.sub.x and particulates from engine exhaust comprises a first stage that plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, and a second stage, which preferably occurs simultaneously with the first stage, that converts NO.sub.2 and carbon soot particles to respective environmentally benign gases that include N.sub.2 and CO.sub.2. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced while carbon soot from trapped particulates is simultaneously converted to CO.sub.2 when reacting with the NO.sub.2 (that converts to N.sub.2). For example, an internal combustion engine exhaust is connected by a pipe to a chamber where carbon-containing particulates are electrostatically trapped or filtered and a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. Volatile hydrocarbons (C.sub.x H.sub.y) from the trapped particulates are oxidized in the plasma and the remaining soot from the particulates reacts with the NO.sub.2 to convert NO.sub.2 to N.sub.2, and the soot to CO.sub.2. The nitrogen exhaust components remain in the gas phase throughout the process, with no accompanying adsorption.

Plasma regenerated particulate trap and NO.sub.x reduction system

A two-stage method for NO.sub.x reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO.sub.x gases in an oxygen-rich exhaust and is intended to convert NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. The second stage employs a lean NO.sub.x trap to convert such NO.sub.2 to environmentally benign gases that include N.sub.2, CO.sub.2, and H.sub.2 O. By preconverting NO to NO.sub.2 in the first stage with a plasma, the efficiency of the second stage for NO.sub.x reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, such as propene. A flow of such hydrocarbons (C.sub.x H.sub.y) is input from usually a second pipe into at least a portion of the first chamber. The NO.sub.2 from the plasma treatment proceeds to a storage reduction catalyst (lean NO.sub.x trap) that converts NO.sub.2 to N.sub.2, CO.sub.2, and H.sub.2 O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO.sub.x are simultaneously reduced while passing through the lean-NO.sub.x trap catalyst. The method allows for enhanced NO.sub.x reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Disclosed is a method of producing thin films by sintering which comprises:

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Livermore, CA, United States of America

Raymond M Brusasco