Abstract: A sound absorbing mechanism using a porous material has a sound absorbing plate of a thin plate porous material made by partially heating for welding plastic particles and a supporting member for supporting the sound absorbing plate and forming a back air space. More than one pair of resonators having a separated back air space in the aforementioned back air space are fixed to the sound absorbing plate, and the resonators are disposed to be opposed to a sound insulator with the supporting member between. Plural reflecting members or increased sound absorbers may be disposed to be opposed to the surface of the sound absorbing plate opposite to the surface equipped with the resonators, or a perforated protecting plate fixing the plural reflecting members or the increased sound absorbers thereon are may be equipped. The sound absorbing mechanism has a superior sound absorption characteristic from lower frequencies to higher frequencies.

Abstract: Heat radiating fin plates in a curved shape are radially arranged on a heat radiating surface of a heat transfer plate, and a space is provided so as to be surrounded by inner edges of the heat radiating fin plates. The heat radiating fin plates have sidewalls formed with projections.

Abstract: A sound absorbing mechanism using a porous material has a sound absorbing plate of a thin plate porous material made by partially heating for welding plastic particles and a supporting member for supporting the sound absorbing plate and forming a back air space. More than one pair of resonators having a separated back air space in the aforementioned back air space are fixed to the sound absorbing plate, and the resonators are disposed to be opposed to a sound insulator with the supporting member between. Plural reflecting members or increased sound absorbers may be disposed to be opposed to the surface of the sound absorbing plate opposite to the surface equipped with the resonators, or a perforated protecting plate fixing the plural reflecting members or the increased sound absorbers thereon are may be equipped. The sound absorbing mechanism has a superior sound absorption characteristic from lower frequencies to higher frequencies.

Abstract: A porous-plastic bearing comprises a porous-plastic sliding bearing member which is formed by gathering a cluster of plastic particles each having a volume in the range of from about 0.004 mm.sup.3 to about 4 mm.sup.3 and sintering the cluster of plastic particles while setting its porosity at a selected value in the range of from about 10% to about 30%. Furthermore, the sliding bearing member comprises a plurality of plastic particles in any longitudinal or cross section. Pores formed within the sliding bearing member are impregnated with or filled with a lubricating agent.

Abstract: The present invention concerns a method of preparing a porous structural unit comprising a plurality of layers having different specific gravities by pressing and heating a material including resin particles between opposing molds having a temperature difference to thereby cause the fusion or bonding of the resin particles, and a porous structural unit which improves acoustic absorption properties and heat insulation properties and in which the specific gravity is continuously changed.

Abstract: A sound attenuator has at least one sound absorber composed of a hollow body of a hard porous material and an outer or inner layer of air, and exhibits good sound-absorbing property even in a low frequency range, even if the hollow body has a small wall thickness. The hollow body may be provided with projections or a semicircular or otherwise shaped part or parts, or both, serving to maintain the outer or inner layer of air in proper shape. The device is inexpensive and yet is very reliable in quality. When the device is long, the projections in linear form are particularly useful for restraining any flanking transmission of noise and thereby enabling the device to achieve a higher rate of attenuation per unit length. The sound-absorbing property of the device can be controlled over a wide range of frequencies if the hollow body has a porosity varying continuously in a specific direction.

Abstract: A blower comprises an impeller which can function to raise the pressure of a fluid and delivers it; a driving device for driving the impeller; and a fan casing which includes a fluid path to inspire the fluid from the outside and deliver it to the outside through the impeller; wherein the fan casing is at least partly formed by a hard porous structural unit whose specific gravity is continuously changed in at least one of the direction of thickness and a direction of surface.

Abstract: The present invention concerns a method of preparing a porous structural unit comprising a plurality of layers having different specific gravities by pressing and heating a material including resin particles between opposing molds having a temperature difference to thereby cause the fusion or bonding of the resin particles, and a porous structural unit which improves acoustic absorption properties and heat insulation properties and in which the specific gravity is continuously changed.