Abstract: A surface acoustic wave device including a thin layer of piezoelectric material, a layer of molecular bonder, and a carrier substrate. The thin layer constitutes an acoustic energy guide that augments the performance characteristics of the device. A method for making the acoustic wave device includes a step of molecular bonding between a carrier substrate and a piezoelectric substrate, and then a step for reducing the thickness of the piezoelectric substrate.

Abstract: A surface acoustic wave transducer in which an etching network is superimposed on the conventional networks of electrodes of acoustic transducers. The superposition of these networks makes it possible to obtain a favored direction of propagation of the acoustic waves while maintaining a high quality factor Q comparable with that of conventional bidirectional transducers. Such a surface acoustic wave transducer may find application in mobile radio communication systems.

Abstract: A composite floor or ceiling structure which comprises a profiled steel deck supported by a plurality of I-section steel beams each having an upstanding web bordered by upper and lower flange plates and covered in situ with concrete. The deck comprises a plurality of side-by-side elongate profiled deck members each including an upper generally horizontal surface bordered by downwardly and outwardly inclined side surfaces. The upper flange plate of each beam has formed in its upper surface a plurality of grooves in a pattern to increase bonding between the beam and its covering of concrete. Preferably, each supporting beam is rolled as a single piece with the width of its lower flange plate greater than that of its upper flange plate to define a supporting platform for the steel deck.

Abstract: A method of filling via holes between a lower conductive layer and an upper conductive layer whereby the hole is filled by the lower conductive layer. By optimizing conditions such as compressive stress and temperature during the deposition of the various layers, the method of the present invention ensures that at a predefined temperature, compressive force on the lower conductive layer causes hillocks to form inside the via holes.

Abstract: A valve apparatus (2) for selectively distributing the sequential passage of separate, organic fluids to a common receiver, such as a reaction vessel. The valve apparatus comprises a valve body member (16) having multiple openings (56) and a plurality of separate conduits (54) each communicating a fluid source with one of the openings. The body member also has a common passage (60) with circular groove portions (62) surrounding the openings so that fluid flows radially outward from the openings toward the common passage. A plurality of pistons (30) are individually reciprocable between first and second positions for controlling fluid flow between associated openings and the common passage. The invention also provides a system (100) and method for measuring and delivering a precise quantity of each of the organic fluids, e.g., chemical reagents, to the reaction vessel.

Abstract: A valve apparatus (2) for selectively distributing the sequential passage of separate, organic fluids to a common receiver, such as a reaction vessel. The valve apparatus comprises a valve body member (16) having multiple openings (56) and a plurality of separate conduits (54) each communicating a fluid source with one of the openings. The body member also has a common passage (60) with circular groove portions (62) surrounding the openings so that fluid flows radially outward from the openings toward the common passage. A plurality of pistons (30) are individually reciprocable between first and second positions for controlling fluid flow between associated openings and the common passage. The invention also provides a system (100) and method for measuring and delivering a precise quantity of each of the organic fluids, e.g., chemical reagents, to the reaction vessel.

Abstract: A method of forming a planarized self-aligned integrated circuit structure suitable for forming CMOS circuitry is provided. The method involves using first and second barrier layers to define the dopant regions for first and second wells, respectively. The first barrier can be formed of a silicon nitride layer covered with a silicon oxide layer. The first barrier layer prevents doping of the silicon wafer except in those regions not covered by the first barrier layer (i.e., the first wells). The second barrier layer is formed by oxidizing the silicon wafer. Only the regions not covered by the first layer are oxidized. The second wells are defined by the second barrier layer. Because some of the silicon of the first wells is consumed to form the second barrier layer, the height of the first wells following the formation of the second barrier layer is less than that of the second wells.

Abstract: A surface acoustic wave device for generating an output signal with only a symmetric or only an asymmetric vibration acoustic wave mode in a piezoelectric substrate. The device has first and second transversely spaced transducers and the device is driven from both the first and second transducers. A third transducer is between and acoustically coupled to the first two transducers. The electrodes of all three transducers are arranged with respect to each other so as to cause only a symmetrical acoustic vibration mode or only an asymmetrical acoustic vibration mode in the piezoelectric substrate.

Abstract: Method for determining at least one characteristic of a casing cemented in a borehole, such as cement bond and casing thickness, from a reflected acoustic signal S(t) obtained by directing an acoustic pulse at a substantially normal incidence towards a radial sector of the wall of the casing, the pulse stimulating thickness resonance within the walls of the casing. The method according to the invention comprises the steps of: determining a first time window corresponding to a first portion of signal S(t) including the initial reflection from the casing and subsequent acoustic returns due to resonance, determining a second time window corresponding to a second portion of signal S(t) mainly including the initial reflection from the casing, and determining the casing characteristic from information related to resonance contained in the first time window while normalizing the information by information contained within the second time window.

Abstract: Novel GSPUDT structures are disclosed with 3/8.lambda. and 5/8.lambda. group sampling with 3.lambda. and 5.lambda. group responses. Reflectionless or unidirectional transducers, and broadband notch elements are all implementable with these new configurations. These GSPUDTs are similar to the conventional SPUDT and the "Hopscotch" transducers in that single level versions are reflectionless. Unidirectional characteristics are only obtainable from a two-level structure.

Abstract: An electrode structure for use with a surface acoustic wave device which has the same velocity as the transducers and the gratings forming the device but no reflections and which can be used to vary structure reflectivity.

Abstract: An electrode structure for use with a surface acoustic wave resonator which has the same velocity as the transducers and gratings but no reflections; a second embodiment provides an electrode structure having a velocity equal to the velocity of the transducers and gratings but that has a coefficient of reflectivity that can be predetermined by varying the width of the electrodes in the electrode structure.

Abstract: A single-phase unidirectional surface acoustic wave transducer comprising a piezoelectric substrate and a transducer having localized symmetry and constructed for establishing a predetermined separation between the centers of acoustic wave reflection and transduction on said substrate by selectively orienting the transducer on a specific cut of said substrate to achieve a separation between said centers in a continuum of achievable phase angles of 0.degree.-360 .degree..

Abstract: The present invention discloses a gas burner for a solid fuel effect gas fire. The burner comprises an integrally formed metal casing defining a gas/air mix chamber. A gas/air mix supply pipe connects with the chamber and a number of burner bores are provided in a wall of the casing. Simulated solid fuel elements can then be located above or on the said wall of the casing so as to not close said burner bores. Age will not affect the performance of the burner as can happen in prior art burners where the casing is formed by an open trough closed by a ceramic plaque where gas/air mix bores extend through the ceramic plaque which is moulded with a number of simulated fuel elements on its upper surface, and sealed by mastic or filler to the rim of the trough which mastic deteriorates with age.

Abstract: A precipitation-hardenable martensitic low alloy steel for use in producing forgings having an improved combination of strength and toughness. The steel may be quenched directly from forging temperature. The composition of the steel consists essentially of, in weight percent, less than 0.20 carbon, 1.0 to 2.5 manganese, 0.10 to 1.5 silicon, 0.01 to less than 1.0 of at least one carbide, nitride or carbonitride forming element which may be niobium, titanium, vandium aluminum, zirconium or tantalum, less than 0.05 nitrogen, 0.01 to less than 2.0 of at least one of molybdenum, nickel and chromium and the balance iron. The steel upon quenching directly from forging temperature has a yield strength of 90,000 to 165,000 psi, a tensile strength of 120,000 to 210,000 psi, impact energy greater than 15 foot pounds at -22.degree. F. and a ductile-to-brittle transition temperature between minus 40.degree. F. and -25.degree. F.

Abstract: A burner comprising a primary mixing chamber having one or more gas inlets and one or more primary air inlets; and one or more secondary mixing chambers, a perforated portion being provided in a side wall of each of said secondary mixing chambers, and each of said secondary mixing chambers communicating with the primary mixing chamber; each primary air inlet 6 comprising an aperture in a wall of the primary mixing chamber and a sliding member attached to the primary mixing chamber over the aperture and movable between a first limit position when the aperture is completely covered by the member and a second limit position when the aperture is completely uncovered by the member, means being provided to retain the member at any position intermediate the first and second limit positions.