Abstract: Three dimensional printed objects having surface coatings, such as a hydrophobic coating or metalized surface, 3D printed substrates having an outer surface that can be tuned by application of such a coating, and methods for the fabrication of such objects and substrates are described. A surface initiator is incorporated into the 3D substrate during layer-by-layer printing, and the surface coated by surface-initiated atom transfer radical polymerization (SI-ATRP).

Abstract: A sound absorbing structure comprising a set of nesting components having increasing size, each of said components being enclosed by the next larger said component, each of said components and its next larger component defining an aperture and a cavity, and said apertures and said cavities forming a set of Helmholtz resonators having increasing size, dissipating sound energy over a wide frequency range.

Abstract: The present invention disclosures a central air-conditioning energy conservation fuzzy control method and fuzzy controller, including: micro-computer, input circuit, output circuit, protective circuit, communication interface circuit, power and micro-computer control program, it is based on the human (expert)'s rich experience and thought to form a fuzzy rule to make inference and judgment, it imitate the expert to resolve the complicated problems in the air-conditioner operation. The precise mathematical model has no need to be established for the controlled central air-conditioner, but only the fuzzy description is needed to realize the controlling. This kind of controlling is more conform the complexity, dynamics and fuzziness of the central air-conditioner, it makes the controlling simple and could realize a best central air-conditioning system operation—safety, comfort and energy conservation.