Abstract: To protect digital content, a content player is installed on a content user device. A unique identifier for the content player installed on the content user device is provided to a central content storage entity. A license to play proprietary digital content stored on the central content storage is purchased from a storefront on the central content storage entity. The proprietary digital content includes an original work of authorship protectable by copyright. Content-player-specific digital content from the central content storage is downloaded to the content user device. The content-player-specific digital content includes encoded content of the proprietary digital content embedded with the unique identifier. The content player confirms that the unique identifier embedded with the encoded content matches the unique identifier provided for the content player before allowing play of the proprietary digital content on the content player.

Abstract: A method of cleaning a surface of an article using cleaning liquids in combination with acoustic energy. Preferably, an ultradilute concentration of a cleaning enhancement substance, such as ammonia gas, is dissolved in a liquid solvent, such as filtered deionized water, to form a cleaning liquid. The cleaning liquid is caused to contact the surface to be cleaned. Acoustic energy is applied to the liquid during such contact. Optionally, the surface to be cleaned can be oxidized, e.g., by ozonated water, prior to cleaning.

Abstract: A method of cleaning a surface of an article using cleaning liquids in combination with acoustic energy. Preferably, an ultradilute concentration of a cleaning enhancement substance, such as ammonia gas, is dissolved in a liquid solvent, such as filtered deionized water, to form a cleaning liquid. The cleaning liquid is caused to contact the surface to be cleaned. Acoustic energy is applied to the liquid during such contact. Optionally, the surface to be cleaned can be oxidized, e.g., by ozonated water, prior to cleaning.