Abstract: The present invention relates to an electro-active device having an electro-active structure extending along a minor axis (36) which is curved, for example in a helix around a major axis (37). The electro-active structure comprises successive electro-active portions (35) extending around said minor axis and arranged with electrodes to bend, when activated, around the minor axis (36) such that bending of the successive portions (35) is concomitant with rotation of the electro-active structure about the minor axis (36) adding incrementally along the minor axis (36). The electro-active structure generates displacement out of the local plane in which the minor axis is curved. The electro-active structure may be continuous electro-active member (35) extending along and curving around the minor axis (35), for example helically to form a helical helix. Alternatively, the electro-active structure may be a plurality of discrete elements (211) connected together.

Abstract: In its first aspect the invention provides an electromechanical acoustic transducer (5) which is resistively terminated at the rear with a closely-coupled sound absorber (7) made from an aerogel with good acoustic absorption at low frequencies. The invention also provides an aerogel suitable for this use and which is a conglomerate of small particles packed so that there are spaces left therebetween to allow the passage of sound. Moreover, the invention provides an aerogel suitable for this use and comprised of multiple layers (17a etc.) of materials of graded properties, or comprised of material of continuously varying properties throughout the thickness of the absorbing structure, in the principal direction of sound from the source.

Abstract: The present invention relates to a loudspeaker (480), comprising: a support (483); a sound-generating element (481) mounted to the support for vibration to generate sound; and an electro-active device (485) coupled between the support and the sound-generating element for vibrating the sound-generating element (481) in response to an electrical signal.

Abstract: A backscattered electron detector capable of detecting electrons backscattered from a substrate includes a p-n junction diode having a p-doped semiconductor in contact with an n-doped semiconductor and a surface to receive the backscattered electrons. The backscattered electron detector also has a diode voltage source adapted to electrically bias the diode relative to the substrate by a diode bias voltage of at least about 500 V to increase the number or energy level of the backscattered electrons received by the diode. A signal amplifier may be used to process an input signal from the diode and generate an output signal that is amplified and passed to a controller that uses the amplified signal to locate a fiducial mark on the substrate.

Abstract: A method and apparatus for a charged particle scanning system and an automatic inspection system, including wafers and masks used in microcircuit fabrication. A charged particle beam is directed at the surface of a substrate for scanning that substrate and a selection of detectors are included to detect at least one of the secondary charged particles, back-scattered charged particles and transmitted charged particles from the substrate. The substrate is mounted on an x-y stage to provide at least one degree of freedom while the substrate is being scanned by the charged particle beam. The substrate is also subjected to an electric field on it's surface to accelerate the secondary charged particles. The system facilitates inspection at low beam energies on charge sensitive insulating substrates and has the capability to accurately measure the position of the substrate with respect to the charged particle beam.

Abstract: There is disclosed numerous embodiments of a method and apparatus for a particle scanning system and an automatic inspection system. In each of these a particle beam is directed at the surface of a substrate for scanning that substrate. Also included are a selection of detectors to detect at least one of the secondary particles, back-scattered particles and transmitted particles from the substrate. The substrate is mounted on an x-y stage to provide it with at least one degree of freedom while the substrate is being scanned by the/particle beam. The substrate is also subjected to an electric field on it's surface to accelerate the secondary particles. The system also has the capability to accurately measure the position of the substrate with respect to the charged particle beam. Additionally, there is an optical alignment means for initially aligning the substrate beneath the,particle beam means.

Abstract: An optical fiber moisture sensor is prepared by coating an optical fiber with a thin film of plasma polymerized hexamethyldisiloxane and ammonia, approximately 1-2 .mu.m thick. The light transmission characteristics of such a coated optical fiber change as a function of moisture conditions in an environment to which the coating is exposed. Accordingly, the coated optical fiber may be utilized by sensing changes in moisture conditions in an environment by being placed in the environment, causing light to be transmitted through the fiber and detecting changes in the light transmitted through the fiber as a function of the moisture conditions in the environment.

Abstract: An on-line gas-in-oil monitoring apparatus and method extracts certain reducing or combustible gases from oil and detects their presence and concentration substantially simultaneously using a sensor. The sensors are sintered metal oxide semi-conductors with adsorbed oxygen. The presence of a reducing or combustible gas proportionally increases the conductivity of the semi-conductor. Any resultant change in conductivity indicates the presence and concentraton of the reducing or combustible gas in the semi-conductor. After the analytical cycle the sensors are regenerated by exposure to oxygen.

Abstract: Disclosed is a method of making an insulated conductor by coating a conductor with a triazole and applying the insulation over the triazole coating. The triazole is preferably benzyltriazole or tolyltriazole. It can be applied dissolving the triazole in water, immersing the conductor in the solution and evaporating the water. The invention is particularly useful with epoxy powder coatings on copper conductors which are used in perchloroethylene containing insulating fluid.

Abstract: A transformer is disclosed which contains a dielectric fluid of tetrachloroethylene. The dielectric fluid is ultra pure in that it contains less than 100 ppm of chlorohydrocarbons. A diluent, such as mineral oil, may be mixed with the tetrachloroethylene. The fluid can also contain 30 to 100 ppm of an inhibitor.

Abstract: A transformer is disclosed which comprises a tank comprising a laminated magnetic core and a winding immersed in a fluid which comprises bright stock catalytically hydrogenated to an aromaticity of 5 to 30 percent. This fluid provides inexpensive insulation for transformers without the need for additives to obtain acceptable physical and electrical properties.

Abstract: Apparatus for holding open a door or similar closure member for a limited period, which may be predetermined, whereupon the door is automatically released and is able to return to its closed position, includes suction means for attachment to the door and/or surface against which the door is to be held in face-to-face relationship. The period of time during which the suction means is active may be determined by means of an air leakage to the suction means, or by means of a spring acting against the suction means.