Abstract: A sensor for detecting the presence of a particular chemical by determining the absolute frequency shift in the oscillating frequency of an antibody-coated oscillator. Specific antibodies deposited on a high Q crystal oscillator detect the change in frequency as chemical particulates become trapped by the antibodies and change the effective mass of the crystal. In one embodiment, two oscillating crystals are used, one that has been coated with the antibodies, and one that is uncoated. This permits detection of frequency differences between the oscillating frequencies of the two crystals, thus eliminating pressure, temperature, and humidity corrections that conventionally must be made. The sensor maintains a high specificity by using antibodies that are specifically related to the chemical to be detected, while achieving relatively good sensitivity by using high Q oscillators, such as quartz or sapphire, and eliminating drift problems due to temperature, pressure, and humidity.

Abstract: A piezoelectric pressure sensor is provided with a sensor housing including an inner sensor housing, accommodating an piezoelectric element, and an outer sensor housing threaded to a test article. The inner sensor housing is attached to the outer sensor housing in such a manner that a prestress applied to the piezoelectric element does not change due to an axial strain in the outer sensor housing. The axial strain is produced when the outer sensor housing is mounted to a test article.

Abstract: A sensor (11, 12, 13, 15) suitable for use as a viscosity sensor, a chemically selective sensor, or a chemically specific sensor. The sensor (11, 12, 13, 15) is a surface transverse wave (STW) device that, for solute concentration measurements, includes a binding layer (18) selected to bind to the solute to be measured. This binding layer (18) can be an antibody so that the sensor detects a particular antigen.

Abstract: A pressure sensor particularly for measuring pressure within a diesel fuel pump comprises a screw-threaded bolt having a head and a shank and having a bore extending through the bolt through the head and shank. A transducer comprising a piezoelement is disposed in the bore, an electrical terminal extends from the bore through the head of the bolt, an electrical insulator is disposed between the transducer and bore, a threaded element positions one side of the transducer in the bore against the terminal, a spring in the bore extends from the shank end of the bore to bear against the opposite side of the transducer, and an incompressible material surrounds the spring in the bore to transmit a pressure force from a fluid pressure zone in the pump through the shank end of the bore to the transducer to provide a signal from the transducer representative of the pressure in the zone.

Abstract: A method for sensing pressure within a work object including placing an electrically deformable member on the work object so as to cover a portion of the surface area thereof; applying electrical energy to the member to cause the member to deform thereby applying pressure to the portion of the surface of the work object; and sensing the tension in the member as a result of the amount of resistance to deformation imparted by the pressure within the work object.

Abstract: In a pressure transducer (11), the diaphragm (14) is fastened at the front side of the housing (10) facing the combustion chamber of an internal combustion engine by weld connections. The pressure acting on the diaphragm (14) is transmitted via the plunger (16) to a sensor block (18) including a plurality of piezoelectrically acting crystals (19, 20). The quartz disks (19, 20) are glued together with one another and with an intermediate electrode (21) as well as with the housing (10) of the pressure transducer (11) by a conducting glue. The plunger (14), the abutment (23) and the piezoelectrically acting crystals (19, 20) are connected in the housing (10) so that force transmission to the crystals (19, 20) occurs without mechanical pretensioning. The pressure transducer (11) is virtually free of dynamic temperature errors and enables a relatively exact determination of the pressure curve with respect to time in the combustion chamber of an internal combustion engine in long-term operation.

Abstract: An electromechanical sensor is provided which comprises: first semiconductor wafer including a first stop surface residing in a first shallow recessed region of the first wafer; a second semiconductor wafer; wherein the first and second semiconductor wafers are laminated together such that the first recessed region of the first wafer and the second wafer define a first chamber in which the first stop surface and the second wafer are disposed close enough together such that the first stop surface restrains the second wafer from deflecting beyond the first stop surface; and an apparatus for measuring deflection of the second wafer.

Abstract: The present invention is a device for characterizing pressure distributions on a rigid surface with respect to at least one reference (x) axis. The device includes a substrate electrode disposed on the rigid surface for which the pressure distribution is to be characterized. An electrically conductive material may form the substrate electrode, or where the rigid surface itself is electrically conductive, that rigid surface may form the substrate electrode. A piezo film is disposed on and overlying the rigid surface. A sensor electrode is disposed on and overlying at least part of the piezo film. In one form of the invention the sensor electrode of a measurement cell is a composite electrode including at least two electrically isolated portions.

Abstract: A method of making a microenvironmental sensor for neurological use in which the sensor is formed on a silicon wafer by the use of known integrated circuit techniques. A mask is applied to define the outline of the sensor, trenches are etched surrounding the sensor by the use of an anisotropic etchant and the sensor is separated by etching surplus silicon from the rear surface of the wafer.

Abstract: A sensor tip (10) for use in a robotic hand has a three-dimensional compliant elastomeric body (12) with an outer boundary (22) having a circular base (24) and a convex surface (26) extending therefrom. Four strain transducers (14, 16, 18, and 20) produce electrical signals indicative of the strain at various positions near the boundary of the elastomeric body (12) resulting from forces exerted upon the sensor tip (10) by an object which the robotic hand is manipulating. The transducers (14, 16, 18, and 20) are positioned about the convex surface (26) so as to produce signals that may be decoupled to determine the normal and tangential forces and the applied torque. A buffer amplifier circuit (34), one for each of the transducers (14, 16, 18, and 20), receives the signals and provides quasi-steady state force information. The circuit (34) connects the respective transducer (40) in a feedback loop around an amplifier (36) and has desirable attributes for static charge buffering.

Abstract: A vortex sensor 14 for measuring a flow rate of a fluid flowing through a flow passage. The flow rate is measured by detecting alternating pressure variations 26a and 28a generated by a shredding body 16 placed in the flow passage. The vortex sensor 14 includes a sensor housing 32 having two cavities 44 and 46 interconnected by a channel 42. An Axle 52 of a spool member 34 is slideably disposed in the channel 42 and allows each of two flange members 54 and 56, connected proximate each end of the axle 52, to shuttle back and forth with respect to the sensor housing 32. A piezoelectric sensing element 62, 64 and a biasing mechanism 58, 60 are disposed between the flange members 54 and 56 and the sensor housing 32. The alternating pressure variations are applied to each flange member 54, 56 causing the spool member 34 to shuttle back and forth. When the spool 34 moves, mechanical forces are coupled to each sensing element 62 and 64 by biasing mechanisms 58 and 60.

Abstract: A vibration/acceleration sensor is provided which includes a basic sensor unit fixed to a casing adapted to be mounted on a body the vibrations of which are to be detected. The sensor unit is surrounded by a resinous material having a low heat transfer coefficient. The sensor unit includes a vibration detecting unit including a piezoelectric bending vibrator, thin plates each formed of, for example, a resinous material having a low heat transfer coefficient, provided respectively on the upper and lower surfaces of the vibration detecting unit, and a signal processing circuit formed on the upper thin plate.

Abstract: A semiconductor pressure transducer for detecting a pressure applied to a diaphragm.

Abstract: A single transducer body having a sealing arrangement including both shoulder sealing surfaces and front end sealing surfaces to seal with mounting holes of component at offset shoulder or front end sealing surfaces.

Abstract: An impulse sensor comprises a transducer container vessel of a cylindrical shape including a pair of stocky sections connected to one another by a midsection of a reduced cross section area, a force transmitting member extending from one end of the transducer container vessel and a force receiving member connected to the force transmitting member, wherein two Piezo electric elements are respectively contained in two cavities respectively included in the two stocky sections of the transducer container vessel. Each of the two Piezo electric elements has a pair of electrodes respectively disposed on the two opposite sides of a reference plane including the central axis of the combination of the transducer container vessel and the force transmitting member. Electrical signals supplied from the four electrodes are combined in such a way that the noises generated by the mechanical vibrations are cancelled and signals representing forces experienced by the force receiving member are obtained.

Abstract: A sensor employs a SAW oscillator heated above the ambient by converting RF energy to heat via acoustic dissipation in energy absorbers located outside the path of propagation. The oscillator utilizes a delay line designed to support single mode operation, fabricated on a substrate. Low insertion loss results from placing the energy absorbers outside the propagation path. Thermally conductive paths around the substrate periphery reduce thermal gradients. Used to measure fluid flow, fluid is directed across the SAW delay line lowering the substrate temperature which is elevated by the heat generating energy absorbers outside the propagation path. The temperature reduction changes the oscillator frequency, indicative of the gas velocity. In operation, gases are passed across the top of the delay-line while liquids are passed across the bottom of the delay-line in a back-side sensing operation.

Abstract: A hail sensor is disclosed which contains a piezoelectric transducer positioned to produce an output signal when it is vibrated by a hailstone. In one embodiment, the transducer is mounted on a perforated member which is exposed to falling precipitation. In an alternative embodiment, the hailstone impacts a rebound surface and is deflected toward the transducer where an electrical output is produced.

Abstract: A pressure measuring instrument for the measurement of the combustion chamber pressure in a cylinder of an internal combustion engine, comprises a piezoelectric pressure sensor. The sensor includes an annular disk-like electrode with an output terminal, a piezoelectric element in contact with said electrode, a pair of annular pressure acting members having interposed therebetween said electrode and said piezoelectric element, and a lead. The piezoelectric pressure sensor is disposed between a first wall on a cylinder head and a second wall of a spark plug.

Abstract: Monitoring explosive devices is accomplished with a substantially z-cut lithium niobate crystal in abutment with the explosive device. Upon impact by a shock wave from detonation of the explosive device, the crystal emits a current pulse prior to destruction of the crystal. The current pulse is detected by a current viewing transformer and recorded as a function of time in nanoseconds. In order to self-check the crystal, the crystal has a chromium film resistor deposited thereon which may be heated by a current pulse prior to detonation. This generates a charge which is detected by a charge amplifier.

Abstract: A spark plug with pressure sensor comprising; a center electrode having a high voltage terminal; an insulator provided around said center electrode to securely support it; a tubular metallic shell provided to support said insulator at its inner side; a pressure sensor having a piezoelectrical element at least enclosed by a casing of a metallic hollow ring; the metallic shell having a diameter-increased portion and a diameter-reduced portion; the casing of the sensor being inserted into the diameter-reduced portion with an inner side of the casing tightly engaging the outer side of the diameter-reduced portion; a mount means having a ring portion and a flange portion; the ring portion tightly inserted into the diameter-reduced portion while the flange portion tightly sandwiching the casing with a step between the diameter-reduced portion and the diameter-increased portion; and the ring portion being welded to said diameter-reduced portion to maintain air-tight relationship between an innerside of the ring port

Abstract: A pressure measurement apparatus is provided which comprises: a housing formed from a thermoplastic material and defining a chamber, the housing including an upper wall region and a lower wall region and first and second opposed side-wall regions disposed between the upper and lower wall regions, the upper wall region including first and second vent ports formed therein; a semiconductor pressure transducer mounted within the chamber, the pressure transducer including a first surface in communication with the first vent port and including a second surface in communication with the second vent port; at least one first pin terminal extending through the first side-wall region, the at least one first pin terminal including a short segment within the chamber and an elongated segment outside the chamber; and at least one second pin terminal extending through the second side-wall region, the at least one second pin terminal including a short segment within the chamber and an elongated segment outside the chamber.

Abstract: A new type of pressure sensor is disclosed here. The sensor is composed of a pair of glass substrates and a ferroelectric liquid crystal which is interposed between the substrates and exhibits piezoelectric effect. Because of crystalline property in liquid phase, the piezoelectric medium can be easily disposed and aligned between the substrates in light of the orientation of the surface contiguous to the liquid crystal layer.

Abstract: A transducer for sensing fluid pressure including an enclosure forming housing, a cup-shaped rubber-like mount having an end wall and an annular side wall for supporting a pressure sensing electronic chip against the inner end wall surface of the mount. The chip is supported against the end wall in covering relation to a small opening in the end wall which connects one side of the chip with atmospheric pressure. A layer of non-hardening sealant gel extending between the inner side wall surface completely covers the chip and transmits fluid pressure to a second surface of the chip but inhibits fluid contact and leakage past the chip.

Abstract: A vortex-shedding flowmeter having two independent force sensors disposed on opposite sides of a tailpiece downstream from the vortex generating element for detecting fluid pressures. The signals derived from the two sensors are merged to form a composite output signal so as to cancel spurious signals caused by fluid pulsations or noise. One or both sensors may be provided with an adjustable gain element to compensate for differences in sensitivity.

Abstract: A piezoelectric vortex flow meter for determining the rate of fluid flow through piping including a hermetically sealed bluff body having a vortex generating plate operably associated with a sensing plate. The vortex generating plate is positioned perpendicular to the fluid flow for creating a "vortex street". A pair of piezoelectric sensors are disposed in a pair of recesses formed in the interior of the sensing plate. Sensing surfaces are formed on each side of the sensing plate adjacent the piezoelectric sensors. The sensing surfaces are formed such that the side surfaces of the sensing plate are free from any discontinuities. The vortices created by the vortex generating plate exert a force on the sensing surfaces which transmit a signal proportional to the force exerted, to the piezoelectric sensors. The piezoelectric sensors transform the mechanical energy into electrical energy readily readable with an appropriate electrical circuit.

Abstract: A unique combination of two transducers. A hot film shear stress gauge and a piezoelectric pressure transducer are coaxially located along the longitudinal centerline of a cylindrical metal shell. The hot film shear stress gauge is exposed to the fluid while the pressure transducer is positioned directly below. Conductors are attached to each and the remaining volume filled with plastic to form a colinear unit. The conductors attached to the hot film element provide power while the conductors attached to the piezoelectric transducer transmit pressure produced electrical signals therefrom. The resulting configuration allows the measurement of fluctuating shear stress and fluctuating pressure to be made simultaneously at a single spatial location at a solid wall bounding a turbulent fluid flow layer.

Abstract: A pressure sensor element is disclosed which essentially comprises a high-strength electric insulating ceramic substrate and a silver coating tightly deposited on the surface of the substrate. When a region of the element is subjected to a high pressure, the electric resistance in the region concerned changes in proportion to the magnitude of the pressure.

Abstract: A structural member having a piezoelectric transmitter film and a piezoelectric receiver film adhered thereto. The transmitter film produces a vibration upon activation by a voltage controlled oscillator which forms part of a phase-lock loop circuit. The vibrations of the structural member generate electric signals on the receiver film, which feed into a phase comparator. The other input of the phase comparator is the output signal of the voltage controlled oscillator. The phase comparator will output a dc signal proportional to the difference in phase between the two signals. When the structural member becomes damped, the phase comparator will go into saturation, thereby producing a voltage which can activate an alarm signal or other device.

Abstract: An apparatus and methods for use in measuring the topography of a surface by contact which comprises a piezoelectric polymer film sensor, such as polyvinyldiene difluoride film, with a body portion and a tip portion, with electrically conductive films adhered to each principal surface of the sensor, and a non-conductive support restraining the sensor a fixed distance from the surface to be measured and with the sensor having an arcuate form when flexed by the surface.

Abstract: A pressure sensor has a metal housing. The housing has a closed-off and fluid-filled pressure space. A diaphragm partitions the pressure space off from the environment and transmits pressures derived therefrom to the fluid. A pressure-sensitive chip of semiconducting material is exposed to the pressure of the fluid and has a piezoresistant and anisotropic effect. Connectors, metal rods for instance, extend pressure-tight and electrically insulated from the metal housing into the pressure space. The connectors can be connected to an electric processing circuit. The pressure-sensitive chip is connected by bonds. To provide a pressure sensor that will be cheaper to manufacture, less sensitive to malfunction, and more precise, the pressure sensor is provided with a base plate of aluminum nitride. At least some areas of its surface are metallized. The pressure-sensitive chip is soldered to the base plate within a metallized area.

Abstract: A method of and apparatus for measuring a stimulus, e.g. a force, applied to a piezoelectric transducer. The method comprises sampling the output of the transducer in response to the stimulus at intervals during application of the stimulus, resetting the output of the transducer to a predetermined value immediately following each sampling step, and summing the values of the sampled transducer output for each sampling step to provide a value indicative of the total applied stimulus. The apparatus of the invention comprises a sensor for sensing the transducer output in response to the stimulus a sampling circuit for sampling the sensed output at intervals during application of the force, a switch for resetting the output of transducer to a predetermined value immediately following each sampling operation, and circuitry for summing the values of the sampled transducer output for each sampling step and generating from them an output value indicative of the total applied stimulus.

Abstract: A transducer for detecting pressure changes in pipes by detecting deformation of the pipes and for converting the pressure changes in the pipes into electric signals uses a bimorph as a sensor element. This bimorph is pressed to the pipe surface by means of a holder. The transducer is free from complicated adjustment of the pressing force against the sensor element, very simple in structure, easy to adjust when mounting, light in weight so as to hardly influence an injection system, and less susceptible to effects of noise due to vibration.

Abstract: This invention discloses a vortex shedding flowmeter comprising a vortex generator-detector constructed into an integrated assembly wherein the vortex shedding frequencies are detected by a pressure detector including at least one panel of extended surface area, which are pivotably or flexibly confined within a planar cavity included in the bluff body that generates a series of vortices shed from the two sides thereof in an alternating pattern at frequencies substantially proportional to the velocity of the fluid stream wherein the bluff body is immersed. The two opposite planar walls of the planar cavity confining a pressure detector panel respectively include a plurality of small holes open to each of the two sides of the bluff body.

Abstract: A multi-component dynamometer for measuring forces and torques includes two force introduction plates and pre-oriented transducer elements without housing arranged between them. Each transucer element comprises typically a rectangular plate and two pre-oriented piezoelectric elements fixed thereon, one of these being sensitive to shear in a direction parallel to one edge of the carrier plate and the other being sensitive to pressure in a direction parallel to the normal of the carrier plate. The pre-oriented transducer elements enable the number of piezoelectric elements and electrical connections to be reduced substantially when assembling measuring platforms, as well as the amount of orientation and testing work. The platforms can be made flatter and more rigid, thereby raising the natural frequency. The electronic measuring and evaluation parts can be integrated partially or wholly into the dynamometer.

Abstract: An instrumented test hammer for use in vibrationally exciting a test object includes a head assembly having an impact tip and a transducer operatively arranged to sense the force of an impact between the tip and object and to convert such sensed force into a proportional electrical signal, a handle extending away from the head assembly, and a cushioned grip surrounding a portion of the handle at a location spaced from the head assembly. The hammer is "tuned", by proper selection of the grip material and by selection of the ratio of the total mass of the head assembly to the combined mass of the handle and grip, such that the node of the first translational resonant mode of the hammer, after impacting against an object, is located substantially proximate the head assembly, independently of the manner by which the grip is held. The improved hammer substantially avoids the generation of spurious electrical signals due to post-impact vibration of the head assembly.

Abstract: A method of detecting structural abnormalities of a structure composed of an electrically conducting crystalline or non-crystalline substance with no band gap. Piezoelectricity and/or pyroelectricity (electric energy) generated by dynamical energy such as pressure and heat applied to the structure are taken out directly from the structure and measured, thereby accurately detecting the distribution and directivity of the structural abnormality resulting from stresses in the structure.

Abstract: A strain sensitive element for use in a system for converting mechanical movement of relatively movable portions of the element into electrical signals, includes a substantially planar substrate comprising an N-type silicon crystal material wherein the substrate includes one or more grooves extending into the substrate defining an integral hinge portion between at least two relatively movable parts. At least one unitary strain gage extends across a groove without any separate support so that the strain gage and the hinge portion are spaced apart. The strain gage is a unitary member derived from the same silicon crystal material of the substrate and comprises P-type silicon material. The strain gage is joined to two of the relatively movable parts of the substrate. At least one unitary conductor extends across a groove without separate support so that the conductor and the hinge portion are spaced apart.

Abstract: A vortex fluid flowmeter having an outer cantilever beam affixed to a sensor body which has bearing surfaces and a flange that serve to locate and fix the sensor in the meter, the outer beam depending from the sensor body, with the upper portion of the outer beam being a hollow circular tube that serves as a flexure, the lower portion of the beam being solid and forming a vane that intrudes into a slot in the bluff body. An inner cantilever beam is provided in spaced relation within the hollow tube portion and secured therein at a point adjacent the bearing surfaces. A strain gage beam is secured to the inner beam and extends upwardly within the tubular portion, with a flexible link secured between the upper end thereof and the inner adjacent wall of the tubular portion.

Abstract: A pressure sensor that provides for multiple diaphragm sensing regions in a side by side configuration which can be formed into a stacked monolithic batch fabricated form. The multiple pressure sensor can be constructed to sense differential or absolute pressure as desired. In preferred forms of the invention, the pressure inlets are all on the same side of the monolithic structure to easily isolate the corrosive pressure media from the sensing means, which as shown comprise strain gage sensors on the sensing diaphragms as well as from the conductors carrying signals from the sensing means. The variable strain gage resistors on the sensor diaphragms are segregated from the media in several differet ways using isolating layers. The stacked sensor configuration insures that the device can be batched fabricated so that a number of sensors can be formed on chips that are stacked and bonded together, and then separated into individual sensors.

Abstract: This process consists of etching a substrate perpendicular to its surface in order to form a recess communicating therewith and in which can move laterally the flexible beam, the communication zone representing the image of the gauge to be produced, placing on the substrate surface a mask provided with an opening facing said recess and extending partly over the beam, passing through the opening a particle beam able to form a deposit of piezoresistive material constituting the gauge and electric contacts, said beam being oriented obliquely with respect to the substrate surface, eliminating the mask and producing electrical conductors on the upper and lower faces of the beam in order to supply current to the gauge.

Abstract: A deflecting diaphragm differential pressure sensor is formed so all electrical elements and connections from external circuitry to the sensor are isolated from the pressure media. The deflecting, pressure sensing diaphragm is made of a semi-conductor material, having piezoresistors disposed on a surface thereof to form strain gages to sense deflection of the diaphragm. The strain gage resistors are media isolated by a layer that overlies the strain gage resistors. All forms of the invention provide environmental protection for the electrical connections for external circuitry, which are subject to corrosion from the pressure media.

Abstract: A semiconductor pressure sensor composed of a substrate formed adopting a thin-film forming technique and a diaphragm which is formed on the surface of the substrate. The sensor includes an insulating diaphragm film which is formed of an etching-resistant material on the main surface of the semiconductor substrate such as to coat it, at least one etching hole provided such as to penetrate the diaphragm film and reach the substrate, a reference pressure chamber which is formed by etching to remove a part of the semiconductor substrate and a disappearing film through the etching hole, and at least one strain gage which is provided at a predetermined position in the pressure receiving region of the diaphragm film.

Abstract: A pressure sensor which uses a tapered shearing piezoresistance type gage to obtain high output. The components are fabricated to produce a surface of the gage which is protected by an oxide film which is turned into phosphorated silicate glass; a sensor surface which has an MOS structure with a silicon substrate; oxide film and polycrystalline silicon film; with the polycrystalline silicon film being fixed at a potential higher than maximum potential generated by the shearing gate, and the surface of the piezoresistance element are where P-type impurity is diffused to a low density being inverted. Thus, the shearing gage is operated substantially in a bulk, and influence due to impurity ion from an external source is removed. Furthermore, the pressure sensor buffers stress arising within the sensor by use of the polycrystalline silicon film, prevents occurrence of local stress by keeping the passivation film from dropping in surface level, thereby minimizing zero offset of the output and drift.

Abstract: Force or pressure measuring device. Between a support member and a force or pressure introduction member elastomeric material is provided which strongly adheres to the two members and is in contact with at least one pressure sensor. With a preferred embodiment the support member is in a potlike form while the force or pressure introduction member is in the form of a piston received by the support member and forming a very narrow gap to the cylindrical surface thereof which gap is essentially completely filled by said elastomeric material.

Abstract: A pressure sensing device including a single crystal of silicon configured to have a diaphram portion, a frame portion and associated circuitry formed on the crystal is described. Piezo-resistive elements on the boundary of the frame and the diaphram portions of the crystal respond to changes in pressure. The piezo-resistive elements, associated elements, and connecting conducting paths are formed by thin film and/or doping techniques to provide a monolithically integrated circuit. The elements are passive and require only application of input voltages and detection of output signals to provide an operative component. Trimmable resistors are provided for compensation and resistive adjustment, and at least one resistive element provides temperature compensation.

Abstract: A semiconductor pressure sensor composed of a substrate formed adopting a thin-film forming technique and a diaphragm which is formed on the surface of the substrate. The sensor includes an insulating diaphragm film which is formed of an etching-resistant material on the main surface of the semiconductor substrate such as to coat it, at least one etching hole provided such as to penetrate the diaphragm film and reach the substrate, a reference pressure chamber which is formed by etching to remove a part of the semiconductor substrate and a disappearing film through the etching hole, and at least one strain gage which is provided at a predetermined position in the pressure receiving region of the diaphragm film. All the processing steps of the sensor are conducted solely on the main surface of the semiconductor substrate, namely, on a single side.

Abstract: A filling and weighing system and method for particulate matter in which the particulate matter in powder form is electrically charged and electrically directed to a container on a weight-frequency sensitive balance. The frequency shift of the balance is a measure of the weight of the powder in the container and when a predetermined frequency shift occurs, this is a measure of a predetermined weight of the powder in the container.

Abstract: Microminiature resonant sensor structures are prepared according to micromachining/microfabrication techniques, which structures include thin-film deposits of piezoelectric materials. Such piezoelectric deposits may be excited electrically by including metallized conductive paths during fabrication, or optically. The resonant frequency of the sensor structure is varied by subjecting it to a physical variable, or measurand, such as pressure, temperature, flow rate, etc. Similarly, the resonant frequency of the devices may be detected electrically or optically. The microminiature resonant structures include ribbons and wires, hollow beam and cantilevered hollow beams, and single- and double-ended double beam resonant structures such as tuning forks.

Abstract: A system is described which comprises many quartz resonators, all formed on the same quartz substrate. The method of fabrication ensures that all the resonators are mechanically and electrically isolated from each other. The oscillation frequencies of the resonators may be individually adjusted to different desired values during fabrication. Since the deviation from the optimum angle of cut is the same for all the resonators because they are all on the same substrate, all the resonators have the same temperature coefficient (change of frequency per degree change in temperature). Mounting the electronic circuitry on the quartz substrate simplifies the interconnections between the resonators and the circuitry, and reduces the size of the resulting device.

Abstract: A method and apparatus for controlling a chemical reaction by heterogeneous catalysis, in which a surface acoustic wave (SAW) is propagated along a surface of a piezoelectric element in contact with liquid or gaseous substances to be chemically reacted, to thus generate an electric field at the surface of the element which initiates and sustains the desired reaction. The catalysis rate can be varied by varying the frequency and/or intensity of the surface acoustic wave. The surface of the element may be coated with a very thin film of a catalytic group 8 metal which can be penetrated by the SAW electric field. In such an embodiment, normal catalysis proceeds via chemisorption, and the SAW element field acts to increase the catalysis rate.