Abstract: Apparatus for resolving movement of a mass within a defined space utilizes at least one electrode proximate to the space to be observed. An AC signal is applied to the electrode, and the current measured from that electrode and also to any other electrodes included in the system, and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending beween the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes. Given the nonlinear spatial dependence of the field, multiple electrodes can reliably distinguish among a set of expected cases.

Abstract: An orientation sensor especially suitable for use in an underground device is disclosed herein. This orientation sensor includes a sensor housing defining a closed internal chamber, an arrangement of electrically conductive members in a predetermined positional relationship to one another within in the chamber and a flowable material contained within the housing chamber and through which electrical connections between the electrically conductive members are made such that a comparison between an electrical property, specifically voltage, of a first combination of conductive members to the corresponding electrical property of a second combination of conductive members can be used to determine a particular orientation parameter, specifically pitch or roll of the sensor.

Abstract: A cased well in the earth is electrically energized with A.C. current. Voltages are measured from three voltage measurement electrodes in electrical contact with the interior of the casing while the casing is electrically energized. In a measurement mode, A.C. current is conducted from a first current carrying electrode within the cased well to a remote second current carrying electrode located on the surface of the earth. In a calibration mode, current is passed from the first current carrying electrode to a third current carrying electrode located vertically at a different position within the cased well, where the three voltage measurement electrodes are located vertically in between the first and third current carrying electrodes. Voltages along the casing and resistances along the casing are measured to determine wall thickness and the location of any casing collars present so as to electrically inspect the casing.

Abstract: The present invention provides methods of determining a smallest dimension of a fabricated device on a semiconductor substrate, methods of determining width of a structure comprising a refractory metal silicide, methods of determining parameters of a semiconductor device comprising a refractory metal silicide, and methods of determining width of an insulative spacer of a semiconductor device.

Abstract: Method and apparatus of measuring a critical current value of a superconducting wire formed by wire sections S(n), n being 1.ltoreq.n.ltoreq.N and initially set to 1, comprising a first step (a) of determining electric currents I(m), m being 1.ltoreq.m.ltoreq.M; a second step (b) of setting m to 1; a third step (c) of passing the electric current I(m) through the wire section S(n); a fourth step (d) of detecting a voltage generated in the wire section S(n) by the electric current I(m); a fifth step (e) of replacing m with m+1; a sixth step (f) of repeating the steps (c) to (e) until m is equal to M; a seventh step (g) of replacing n with n+1; an eighth step (h) of repeating the steps (b)-(g) until n is equal to N, thereby obtaining N.times.

Abstract: A method for resolving presence, orientation and activity of a person within a defined space utilizes at least two electrodes proximate to the space to be observed. A characterization of the position and orientation is obtained by providing a pattern of measurement clusters each associated with a position and an orientation. An AC signal is applied to one electrode, and the current measured from that electrode to any other electrodes included in the system, and which are effectively connected to the ground return of the AC-coupled electrode. A person (or object) to be sensed intercepts a part of the electric field extending between the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed person, whether or not the person provides a grounding path, and the geometry of the distributed electrodes.

Abstract: A method and apparatus for measuring sheet resistance and thickness of thin films and substrates. A four-point probe assembly engages the surface of a film on a substrate, and the thickness of the substrate is determined from the point of contact between the probes and film. A measuring apparatus then outputs a voltage waveform which applies a voltage to probes of the probe assembly. An inverter inverts the voltage and provides the inverted voltage on another probe of the probe assembly, thus inducing a current in these probes of the four point probe and through the surface of the film. Two other probes measure a voltage in the film created by the current. The voltages on the current probes provide a voltage close to zero at the other probes, thus allowing these other probes to measure voltages with greater precision. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform.

Abstract: A device for measuring the levitation force of a high temperature superconductor sample with respect to a reference magnet includes a receptacle for holding several high temperature superconductor samples each cooled to superconducting temperature. A rotatable carousel successively locates a selected one of the high temperature superconductor samples in registry with the reference magnet. Mechanism varies the distance between one of the high temperature superconductor samples and the reference magnet, and a sensor measures levitation force of the sample as a function of the distance between the reference magnet and the sample. A method is also disclosed.

Abstract: A method of determining a response characteristic of a microwave device includes coupling a microwave resonator to the device, loading the resonator with microwave radiation, monitoring the time decay of power from the resonator, and comparing the monitored time decay with a known characteristic of the time decay of radiation in the microwave resonator when loaded with radiation.

Abstract: A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending between the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes.

Abstract: A substantially constant current is conducted in a first direction through an interconnect structure having a barrier layer to determine the lifetime of the structure in the first current direction. A substantially identical current is conducted in a second direction through a substantially identical interconnect structure to determine the lifetime of the structure in the second current direction. These tests are repeated for identical structures but having different barrier layer thicknesses. The results of these lifetime tests are compared to determine the barrier layer's effect on electromigration in the structure, which can be used to design the barrier layer to optimize the structure's lifetime and speed.

Abstract: A method for making an acoustic wave device. The method has steps of providing a substrate suitable for acoustic wave devices and processing the substrate to provide a patterned metallization thereon. The patterned metallization includes an acoustic wave filter pattern. The method also has steps of measuring a sheet resistance associated with the acoustic wave filter pattern, determining a resistance of a test pattern associated with the acoustic wave filter pattern to provide a measured resistance and computing an estimated average linewidth for the acoustic wave filter pattern from the measured resistance and the sheet resistance.

Abstract: The present invention provides a sheet thickness measuring apparatus comprising electrostatic capacity measure means for measuring the electrostatic capacity of a sheet, resistance measure means for measuring a resistance value of the sheet, and calculation means for calculating a thickness of the sheet on the basis of the electrostatic capacity measured by the electrostatic capacity measure means and the resistance value measured by the resistance measure means.

Abstract: A micromechanical sensor in which the impedance of a gap in a conductor, under tunnelling current conditions, is sensed to provide an indication of deflection in the conductor. This provides a new way to sense acceleration, strain, and other parameters which can be translated into a deflection.

Abstract: A method of measuring a cryogenic fluid level utilizing a high temperature ceramic superconductor material driven above its level of critical current density. A high temperature ceramic superconductor is placed in cryogenic fluid and a voltage is applied between two points on the superconductor. The voltage drop is then measured at a third point on the superconductor. This voltage drop corresponds to the change in cryogenic fluid level, and thus can be used to measure the fluid level. Sensitivity of the measurement is increased by driving the high temperature ceramic superconductor above its level of critical current density.

Abstract: An orientation sensor especially suitable for use in an underground device is disclosed herein. This orientation sensor includes a sensor housing defining a closed internal chamber, an arrangement of electrically conductive members in a predetermined positional relationship to one another within the chamber and a flowable material contained within the housing chamber and through which electrical connections between the electrically conductive members are made such that a comparison between an electrical property, specifically voltage, of a first combination of conductive members to the corresponding electrical property of a second combination of conductive members can be used to determine a particular orientation parameter, specifically pitch or roll of the sensor.

Abstract: A method for making an acoustic wave device. The method has steps of providing a substrate suitable for acoustic wave devices and processing the substrate to provide a patterned metallization thereon. The patterned metallization includes an acoustic wave filter pattern. The method also has steps of measuring a sheet resistance associated with the acoustic wave filter pattern, determining a resistance of a test pattern associated with the acoustic wave filter pattern to provide a measured resistance and computing an estimated average linewidth for the acoustic wave filter pattern from the measured resistance and the sheet resistance.

Abstract: Imaging instruments for inspecting products, such as semiconductor chips, e calibrated by providing a reference test structure having features which can be located by electrical measurements not subject to tool-induced shift and wafer-induced shift experienced by the imaging instrument, and by the imaging instrument. The reference test structure is first qualified using electrical measurements, and is then used to calibrate the imaging instrument. The electrical measurements are made by forcing a current between a plurality of spaced reference features and a pair of underlying conductors. Conductive connectors formed in vias in an insulating layer overlying the pair of conductors and individually connected to a respective conductive element formed on the insulating layer are each spaced at progressively greater distances relative to the centerline of the space between the pair of conductors, such that a null-overlay element may be identified.

Abstract: A method and apparatus for measuring sheet resistance and thickness of thin films and substrates. A four-point probe assembly engages the surface of a film on a substrate, and the thickness of the substrate is determined from the point of contact between the probes and film. A measuring apparatus then outputs a voltage waveform which applies a voltage to probes of the probe assembly. An inverter inverts the voltage and provides the inverted voltage on another probe of the probe assembly, thus inducing a current in these probes of the four point probe and through the surface of the film. Two other probes measure a voltage in the film created by the current. The voltages on the current probes provide a voltage close to zero at the other probes, thus allowing these other probes to measure voltages with greater precision. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform.

Abstract: An apparatus and method for detecting defect sizes in polysilicon and source-drain semiconductor devices and methods for making the same. Implemented is a double bridge test structure that includes a resistor path of first semiconductor material, such as doped silicon comprising a plurality of strip segments and with interconnection segments. A plurality of strips of second semiconductor material having a substantially lower resistivity are connected to form parallel circuit interconnections with the corresponding strip segments. The test structure is formed by masking techniques wherein a prescribed mask region enables portions of the silicon resistor or deposited polysilicon to be selectively silicided to form silicide and polycide, respectively. One embodiment for testing for defects in a polysilicon layer uses polycide as the low-resistivity strips, enabling the testing of open and short-circuit defects.

Abstract: A method to estimate the thickness of a brake lining based on the periodic sampling of the output of a temperature sensor embedded in the brake lining. A temperature histogram is created which is compared to calibration histograms stored in an electronic processing unit to yield an estimated brake lining thickness which is transmitted to the vehicle cab or to another on-board electronics unit. A brake wear factor is calculated from the temperature histogram by multiplying the average value of each temperature range by the frequency of occurrence and then summing the results.

Abstract: The invention comprises a method for determining the hole or electron concentration, transition temperature, ratio T.sub.c /T.sub.c (max), or state of doping of a material capable of exhibiting superconductivity when cooled below its critical temperature, by measuring the thermopower of a sample of the material above the critical temperature of the material and determining from the thermopower the hole or electron concentration, transition temperature, ratio T.sub.c /T.sub.c (max), or state of doping of the material as to whether it is underdoped, overdoped or optimally doped. The sample may be differentially heated and/or cooled to generate a temperature difference across the sample, the temperature difference across the sample measured, the voltage across the sample measured, and the hole concentration or similar determined from the measured temperature difference and the measured voltage. Means for determining the hole concentration, transition temperature, or doping of the material is also claimed.

Abstract: A substantially constant current is conducted in a first direction through an interconnect structure having a barrier layer to determine the lifetime of the structure in the first current direction. A substantially identical current is conducted in a second direction through a substantially identical interconnect structure to determine the lifetime of the structure in the second current direction. These tests are repeated for identical structures but having different barrier layer thicknesses. The results of these lifetime tests are compared to determine the barrier layer's effect on electromigration in the structure, which can be used to design the barrier layer to optimize the structure's lifetime and speed.

Abstract: A test structure for submicrometer metrology as used in integral circuit manufacture comprises a bridge conductor divided into three segments by pairs of voltage taps. A first segment has no intermediate taps; a second segment has a number of dummy taps intermediate its ends; and a third segment has a single central tap, which may typically be formed in a different step than the remainder of the test structure, intermediate its ends. Preferably, the central tap extends from the same side of the bridge conductor as the taps at the ends of the third segment thereof. In order to evaluate a manufacturing operation, for example, to monitor the accuracy of registration of successive manufacturing steps, test signals are applied successively between the pairs of pads.

Abstract: Methods of measuring, adjusting and uniformalizing a sectional area ratio of a metal-covered electric wire, a method of cleaning an electric wire, a method of manufacturing a metal-covered electric wire, an apparatus for measuring a sectional area ratio of a metal-covered electric wire, and an apparatus for electropolishing a metal-covered electric wire.Electric resistance values of first and second materials are previously stored respectively so that a sectional area ratio of a metal-covered electric wire is calculated on the basis of the as-stored values and an actually measured electric resistance value of the metal-covered electric wire. Measurement and uniformalization of a sectional area ratio of a metal-covered electric wire and cleaning of an electric wire are carried out by dissolving surface layer parts of the electric wires by electropolishing.

Abstract: A method for determining the position of an armature of a dc-powered solenoid. Electrical circuitry is provided to introduce a small alternating current flow through the coil. As a result, the impedance and resistance of the solenoid coil can be measured to provide information indicative of the armature's position.

Abstract: A dielectric resonator apparatus for measuring the parameters of high temperature superconducting thin film is disclosed having improved means for positioning the dielectric and substrates, holding the resonator components in place during use, suppressing undesirable modes, adjusting the magnetic dipole coupling, and coupling to an electrical circuit.

Abstract: This describes a test pattern and method for measuring dimensional characteristics of features formed on a surface. This is realized and provided by forming a space, defined by the feature, in intersecting relationship with a pair of conductive lines of a test pattern configuration such that the lines are altered at the intersection with the space in accordance with the dimensions of that space, measuring the resistance of at least one of the lines in a region remote from the intersection with the space and the resistance of each line in the region of its intersection with the space, and comparing the resistance of the remote region with the resistances for the region of each of the lines where they intersect the space to thereby establish the position of, and at least one dimension of that space.

Abstract: A process variance detection technique for detecting fabrication processing variances in integrated circuit components, such as resistors or MOSFETs, is based on the decreased sensitivity to processing variations exhibited by components that are up-sized relative to similar components with nominal dimensions. Detection circuitry includes detection components with both nominal and up-sized dimensions, and variance detection involves detecting the differences in operational response of the nominal and up-sized detection components. For bipolar logic, resistors are fabricated with up-sized widths, while for MOS logic, MOSFETs are fabricated with up-sized gate lengths.

Abstract: A process for determining a surface resistance to microwave energy of a superconductive film provides a metallic cavity resonator whose resonator cavity is defined by metallic walls, and positioning a superconductive film whose microwave surface resistance is to be measured as at least part of a wall of the cavity. A dielectric body is applied to a surface of the film and microwave energy is coupled to the cavity through an input antenna and microwave energy is coupled out of the cavity by an output antenna at which signals are produced as a measure of the microwave surface resistance of the film.

Abstract: An apparatus capable of measuring a wet paint film thickness easily and accurately in a non-contacting manner. The apparatus includes a paint film surface data acquisition unit for obtaining paint film surface data indicating a roughness of a paint film surface in a wet state, in a non-contacting manner; a paint medium data input unit for inputting paint medium data specifying a paint medium from which a paint film is formed; and a paint film thickness calculation unit for calculating the paint film thickness from the paint film surface data and the paint medium data according to a dynamic levelling property of a wet paint film.

Abstract: A method and apparatus for measuring film thickness and sheet resistance. A four-point probe engages the surface of a film, and a measuring apparatus outputs a voltage waveform which induces a current in the outer probes of the four point probe and through the surface of the film. The two inner probes measure a voltage in the film created by the current. The current created by the voltage waveform and the voltage created across the inner probes are measured for each voltage level of the waveform. A sheet resistance of the film is calculated by taking a least square fit of the measured current and voltage and calculating the slope of the least square line fit. The sheet resistance is proportional to the slope of the least square line. The thickness of the film is calculated by dividing the film resistivity by the calculated sheet resistance.

Abstract: A sheet thickness measuring apparatus includes an electrostatic capacity measuring device for measuring the eletrostatic capacity of a sheet, a resistance measuring device for measuring a resistance value of the sheet, and a calculator for calculating a thickness of the sheet on the basis of the electrostatic capacity measured by the electrostatic capacity measuring device and the resistance value measured by the resistance measuring device.

Abstract: A method for measuring the thickness of very thin oxide layers on a silicon substrate. A corona discharge source repetitively deposits a calibrated fixed charge density on the surface of the oxide. The resultant change in oxide surface potential for each charge deposition is measured. By choosing a starting value for an assumed oxide thickness, the approximate change in silicon bandbending per corona discharge step is determined. The cumulative changes in bandbending versus oxide surface potential yields an experimental bandbending versus bias characteristic. A theoretical bandbending versus bias characteristic is established. The experimental and theoretical characteristics are matched at predetermined points thereof and then the assumed oxide thickness is iterated until both characteristics superimpose in the silicon accumulation region. The iterated oxide thickness that allows both characteristics to superimpose is the oxide thickness value being sought.

Abstract: A method of measuring the linewidth of an electrical conductor on a semiconductor substrate includes preparing mutually separated test and interconnection areas on a surface of a semiconductor substrate; forming an electrical interconnection conductor on the surface of the substrate in the interconnection area with a substantially uniform linewidth electrically interconnecting elements on the surface; simultaneously with forming the interconnection conductor, forming in the test area a test structure having a plurality of closed loops of the electrical conductor having the same linewidth as the interconnection conductor; measuring the impedance or complex reflection coefficient of the test structure using a head disposed opposite the test area, spaced from the surface, and coupled to the test structure without directly contacting the test structure; and correlating the measured impedance or complex reflection coefficient of the test structure with measurements of geometrically identical structures of conducto

Abstract: An angular position sensor having at least one resistive track which is circular, for example, and at least one cursor. The cursor is adapted to move while in electric contact with the track. The track is closed and continuous and has at least two electric access points. The sensor cooperates with an arrangement for applying separate predetermined electric potentials to the access points and with an arrangement for measuring the resulting electric potential at one of the access points. The cursor is therefore able to rotate through a complete turn without leaving the one resistive track. All angles can be measured and rotation through several turns is possible.

Abstract: A test structure for submicrometer metrology as used in integrated circuit manufacture comprises a bridge conductor divided into three segments by pairs of voltage taps. A first segment has no intermediate taps; a second segment has a number of dummy taps intermediate its ends; and a third segment has a single central tap, which may typically be formed in a different step than the remainder of the test structure, intermediate its ends. Preferably, the central tap extends from the same side of the bridge conductor as the taps at the ends of the third segment thereof. In order to evaluate a manufacturing operation, for example, to monitor the accuracy of registration of successive manufacturing steps, test signals are applied successively between the pairs of pads.

Abstract: An apparatus and method for accurately establishing a predetermined gap between two surfaces, and in particular, between a corona generating device and a photoreceptive member in an electrostatographic printing machine, comprising a first conductive member for being mounted on a first of the two surfaces, a second conductive member for being placed on a second of the two surfaces, the combined thickness of the first and second conductive members being substantially equal to the predetermined gap. A device is coupled between the first and second conductive members, for sensing electrical continuity therebetween.

Abstract: A prepatterned potentiometer precursor includes a precursor substrate; and at least two spaced apart potentiometer precursor patterns on the substrate, each potentiometer precursor pattern including a bridge, two substantially similar end taps transverse to and extending from the bridge, and a center tap transverse to and extending from the bridge and centrally disposed between the end taps wherein the center taps of the bridges are substantially parallel to each other and are substantially wider than the end taps. A method of determining the distance between test features of test patterns on a test piece includes preparing a precursor substrate including at least two electrically conducting spaced apart potentiometer precursor patterns, each potentiometer precursor pattern including a bridge, two substantially similar end taps transverse to and extending from the bridge, and a center tap transverse to and extending from the bridge and centrally disposed between the end taps.

Abstract: An apparatus for determining the relative positions of power outlets within a multi-outlet electrical circuit and, specifically, for determining the first occurring power outlet in a multiple-earth-neutral power system in which earth and neutral wires are interconnected at a distribution point. The apparatus incorporates circuitry for generating a current pulse and probe means for injecting the pulse into a wiring loop which extends between neutral and earth contact terminals of each of the power outlets. The probes are also employed for detecting the voltage drop which occurs along the wiring loop as a consequence of the current flow through the loop, and circuitry is provided for generating a signal which is representative of the voltage drop along the wiring loop.

Abstract: A sheet size detection device for detecting a size of sheets which are held in a cassette body comprises a first guide member for defining the position of the sheets which are held in the body of the cassette, in a first direction of the sheets, the first guide member being movable in accordance with the size of sheets, a second guide member for defining the position of the sheets, in a second direction of the sheets, the second direction being orthogonal to the first direction, the second guide member being movable in accordance with the size of sheets, a first arm having a first resistor and movable with the first guide member, a second arm having a second resistor and movable with the second guide member, the first and second resistors constituting a variable resistor, and a size detector for detecting the size of the sheets on the basis of the resistance value of the variable resistor.

Abstract: The present invention provides a method for determining the granular nature of superconductive materials and devices which includes the steps of: conducting a substantially rectangular current pulse through the superconductive material, maintaining the temperature of the superconductive material at a substantially constant temperature which does not exceed the critical temperature of the superconductive material; determining the amplitude of the current pulse; determining the electrical resistance, R, of the superconductive material resulting from conducting current pulse through the superconductive material; increasing the current until the electrical resistance of the superconductive material becomes saturated; determining the electrical resistance difference, .delta., between the electrical resistance, R, of the saturated superconductive material and a total normal state electrical resistance of the superconductive material; generating a first output signal if .vertline..delta..vertline..ltoreq..epsilon.

Abstract: Apparatus and method for noncontact, radio-frequency shielding current characterization of materials. Self- or mutual inductance changes in one or more inductive elements, respectively, occur when materials capable of supporting shielding currents are placed in proximity thereto, or undergo change in resistivity while in place. Such changes can be observed by incorporating the inductor(s) in a resonant circuit and determining the frequency of oscillation or by measuring the voltage induced on a coupled inductive element. The present invention is useful for determining the critical temperature and superconducting transition width for superconducting samples.

Abstract: A preferred embodiment of the invention is an apparatus for measuring the position of a point with respect to at least one axis. The apparatus includes a reference electrode located at the reference point and at least one axial electrode fixed along the at least one axis. The axial electrode has a signal transmission property, such as resistivity, as measured between a first end and a point along the axis, which signal transmission property varies with the location of the point of measurement. The axial electrode is coupled to the reference electrode, typically capacitively. The apparatus also includes means for applying an electric signal to the reference electrode; means for measuring an output electric signal at the first end of the at least one axial electrode; and means for evaluating the relation between the output electric signal and the input electric signal to determine the position of the reference point relative to the axis.

Abstract: A test structure pattern and method for processing the electrical data extracted from the pattern which allows for the measurement of a short line with a precision on the order of 10 nanometers.

Abstract: Apparatus and method for determining and imaging superconductor surface resistance. The apparatus comprises modified Gaussian confocal resonator structure with the sample remote from the radiating mirror. Surface resistance is determined by analyzing and imaging reflected microwaves; imaging reveals anomalies due to surface impurities, non-stoichiometry, and the like, in the surface of the superconductor.

Abstract: A supervisory system is used for a superconductive transformer which comprises primary to Nth-order windings (N is an integer of not less than 2) windings, and the windings are formed of superconductive lines and are wound around an outer surface of a signal core. The supervisory system can detect quench occurring in the windings. The supervisory system includes N voltage sensors for detecting terminal voltages of the windings of the superconductive transformer, N current sensors for detecting currents of the windings, a magnetic flux detector mounted on the core of the transformer, and a discriminator for discriminating a quenched one of the windings on the basis of change patterns unique to output signals from the voltage sensors, output signals from the current sensors, and an output signal from the magnetic flux detector, and a switch for cutting off supply of an electrical power to the superconductive transformer according to an output signal from the discriminator.

Abstract: The present invention provides a method for measuring the intragranular and ntergranular critical current of a granular superconductive material, comprising the steps of: 1) conducting a substantially rectangular electronic pulse through the material so as to conduct a current through the material such that when the intergranular critical current of the material is exceeded, any grains present in the material remain in a superconducting state when the current level is below the intragranular critical current; 2) measuring the current through the material while conducting the pulse; 3) measuring a voltage difference across the material while conducting the pulse; 4) determining the intergranular critical current through the material by discerning a non-zero voltage difference across the material and contemporaneously measuring the current; and 5) determining the intragranular critical current through the material by varying the current to discern a current level at which the electrical resistance of the materi

Abstract: An interchangeable pinch valve system (10) is provided with a valve body (20) having a longitudinal dimension which is substantially identical to standard longitudinal dimensions for ball, gate and the like type valves of similar flow path diameter. The reduced longitudinal dimension of pinch valve system (10), as compared to prior art systems, is achieved by a flexible-walled tubular sleeve (50) having a pair of transversely directed folds (60, 62) which provide sufficient sleeve material to enable the pinch closing of the flow passage (52) without substantially stretching the tubular sleeve wall (51). The valve body 20 is provided with a pair of recessed openings (22, 24) formed in the interior of valve body wall (21) in parallel spaced relation transverse to the fluid flow axis of the valve for receipt of the respective folds (62, 60), whereby the tubular sleeve (50) is in contiguous contact with the interior surface of valve body wall (21).

Abstract: In a method and apparatus for detecting and locating a quench zone in a superconducting coil, a sensor is positioned adjacent to and in heat transfer communication with the entire length of the superconducting coil. When a portion of the superconducting coil becomes normal, the adjacent portion of the sensor becomes resistive. A series of electrical pulses sent along the sensor are reflected back by the discontinuity in impedance which occurs at such a normal zone. The reflected pulses and echo pulses produced by various terminations on the sensor are detected by an associated receiver and processor which calculates the location of the resistive zone along the sensor and the corresponding quench zone along the superconducting coil using information derived from the pulses. A second embodiment provides two sensors which are adjacent to and in heat transfer communication with the coil which are pulsed from opposite ends.