Abstract: A method for measuring electromigration includes the steps of measuring a corresponding voltage increase across an interconnect as a function of time for a plurality of nonzero heating rates and calculating an interconnect integrity from the voltage increase.

Abstract: An apparatus and method for determining if a stone mounted in an electrically conductive mounting is a true diamond employs a housing to be held in one hand of a user while the other hand holds the mounting. An electrically and thermally conductive probe extends from the housing. The probe is held against the surface of the stone. Two assemblies connected to the probe measure sequentially to determine the thermal conductivity of the stone and the electrical conductivity of the stone. Displays indicate if the assemblies detect the high thermal conductivity of the stone consistent with diamond and the low electrical conductivity of the stone consistent with diamond. This apparatus distinguishes true diamond over such imitations as cubic zirconia with a lower thermal conductivity and moissanite with a higher electrical conductivity.

Abstract: An exhaust gas side electrode is provided on one surface of a solid electrolytic substrate. A reference gas side electrode is provided on an opposite surface of the solid electrolytic substrate so as to be exposed to a reference gas stored in a reference gas chamber. Each lead of the electrode is connected to a signal output terminal. This sensor satisfies a relationship B/A <0.5, wherein ‘A’ represents an overall resistance value of an electric path including the solid electrolytic substrate, the electrodes, and their leads in a sensor activated condition, while ‘B’ represents a resistance value of the leads at a room temperature.

Abstract: The invention includes an apparatus for determining geo-electric data and the density of a porous material. A resistivity-measuring device applies an electrical current through an electrode array to that is part of a non-electrical conductive test cell that is used to measure the resistivity of the porous material that is the test cell. The test cell is a made of a rigid non-electrically conductive material and is a standard shape and dimension. The material that is the test specimen is compacted into the test cell using a standard technique so that the physical properties of the test specimen my calculated. In addition to making a set of standard physical measurement (material unit density and unit moisture content) the test cell is used to measure electrical properties of the test specimen so that a set of electrical constants can be determined for the material under test.

Abstract: This invention relates to an on-line statistical process control device for solder paste and residues. The invention consists of electronics hardware, software, and probing systems. The electrical hardware of the invention provides voltage and current measurements of solder paste materials, the software of the invention controls the hardware, provides real-time complex, non-linear least squares curve fitting for equivalent circuit analysis, data storage and retrieval of circuit parameters and behavior, and statistical process control tracking and charting. The probing systems of the invention allows for 2, 3, and 4 probe surface and bulk measurements of the solder paste and residues.

Abstract: It has been learned that moissanite and other synthetic stones, including synthetic moissanite and synthetic diamond, are distinguishable from natural diamonds based on differing electrical conductivities. The present invention, therefore, provides an apparatus and method for determining a gem type based on its electrical conductivity. In particular, an electronic circuit including the gem under test as part of a circuit path is used to measure its electrical conductivity and, therefore, gem type. The onerous task of determining whether a gem is moissanite or synthetic diamond involves providing a high voltage across a gem surface greater than a breakdown voltage, typically greater than 300 volts, and measuring a minuscule current that flows through the gem. A first and second contact couple the high voltage to the gem under test, where a low impedance detection circuit is used to flag when the contacts are erroneously contacting each other during a measurement.

Abstract: The electric mammograph is an electrical impedance tomograph device for obtaining three-dimensional images of the conductivity distribution in biological tissues. A planar array of electrodes is put in contact with the tissues of interest. An AC source is connected to a single remotely attached electrode and to one of the planar array electrodes. Potential differences between the at rest electrodes in the planar array and a second remote at rest electrode are measured. The images are reconstructed using a modified back projection method.

Abstract: An air-fuel ratio sensor generates linear air-fuel ratio detection signals proportional to concentration of oxygen in exhaust gas from an engine in response to a command voltage from a microprocessor. A bias command signal generated by the microprocessor is provided to a D/A converter which converts it to an analog signal. Thereafter, the signal is provided to an LPF for removing the high frequency components of the analog signal. Output voltage of the LPF is provided to a bias control circuit. A single AC signal which has a predetermined frequency and which is provided with a predetermined time constant (about 159 .mu.s) by the LPF is applied to the air-fuel ratio sensor. Element resistance of the air-fuel ratio sensor is detected based on the voltage of the AC signal and the change in the current level of the air-fuel ratio sensor caused by the application of the AC signal.

Abstract: A conductivity sensor for measuring hematocrit and a sensor housing for a blood analysis instrument using the conductivity sensor are described. The conductivity sensor includes a seven-electrode conductivity measurement cell in which three symmetric pairs of electrodes are arranged on opposite sides of a central electrode. The central electrode is connected to an AC source and the outermost pair of electrodes, which provide a return path for the current, are maintained at a ground or reference potential. The two inner pairs of electrodes measure the voltage drop along the current flow path. This arrangement confines the measurement current and potential within the sensor chamber, thereby preventing the sensor from interfering with other electrochemical sensors that may be provided in the blood analysis instrument. The sensor housing provides a linear arrangement of flow cells defining a fluid flow path through the housing.

Abstract: Provided is a method and metering system for the determination of active ions emitted from certain active substances such as rayon fibers containing fine particles of tourmaline known to exhibit permanent spontaneous polarization. The method comprises: continuously bringing air free from carbon dioxide as a carrier gas into contact with a bed of the active ion-emitting source material to carry off the active ions emitted therefrom; introducing the air after contact with the source material into distilled water; and measuring increase in the electric conductivity of the distilled water caused by the absorption of the active ions from the flow of the air as a carrier gas. The metering system comprises: a feed source of the non-ionic inert gas; a sample holder to contain the source material emitting active ions; a vessel containing distilled water to receive the air carrying the active ions; a means to determine the electric conductivity of the water; and pipelines connecting these parts for the flow of air.

Abstract: This invention relates to an on-line statistical process control device for solder paste and residues. The invention consists of electronics hardwa software, and probing systems. The electrical hardware of the invention provides voltage and current measurements of solder paste materials, the software of the invention controls the hardware, provides real-time complex, non-linear least squares curve fitting for equivalent circuit analysis, data storage and retrieval of circuit parameters and behavior, and to statistical process control tracking and charting. The probing systems of the invention allows for 2, 3, and 4 probe surface and bulk measurements of the solder paste and residues.

Abstract: The electrical impedance of a dumbbell-shaped rubber sheet (1) is measured, and the deterioration of the dumbbell-shaped rubber sheet (1) is detected from the result of the measurement. The present invention relates to a method of detecting a change in the property of a rubber member or a rubber member of a rubber bearing, such as a change in the shape or dimensions thereof, a change in the state of the stress and strain thereof, deterioration thereof, and the like.

Abstract: A solution of active principle, in ionized form, impregnates a layer (2) forming part of the reservoir (1). A measurement of the quantity of active principle contained in this layer is derived from a measurement of the conductivity of this layer. The measurement device comprises a) first (7) and second (10) electrodes placed on either side of and in electrical contact with at least a part of the layer (2) of the impregnated material of the reservoir, b) means (5) for passing the electric current of predetermined strength through the impregnated material and c) means (6) sensitive to the voltage (V) picked up between the electrodes (7, 10) in order to calculate the quantity of active principle contained in the reservoir.

Abstract: The invention includes a method and device for determining the in-situ density of a porous material. A resistivity measuring device applies an electrical current through an electrode array to measure the resistivity of the porous material. The resistivity measuring device may also be used to measure the resistivity of a pore filling fluid. A formation factor and in-situ density constants of the porous material are determined using empirical methods. In-situ moisture content of the porous material is determined. The above data is applied to a general geophysical in-situ density equation to calculate the in-situ density of the porous material.

Abstract: A method and device for determining the hydraulic conductivity of porous materials is disclosed. The method uses a general permeability equation for calculating the hydraulic conductivity. The resistivity of the porous material is measured when the porous material is at least partially saturated with a pore filling fluid. Other data, such as a formation factor, permeability constants of the porous material, and in situ moisture content of the porous material may also be derived or measured. The geophysical permeability equation is then used to calculate the hydraulic conductivity of the porous material from the measurements and data. Methods are also disclosed which provide an average hydraulic conductivity over a given area. A device for determining hydraulic conductivity of a porous material is disclosed which utilizes a plurality of electrodes for conducting electricity to the porous material. A resistivity meter may be attached between the electrodes for measuring the resistivity.

Abstract: A molten metal inclusion sensor probe which is immersed in the molten metal and detects inclusions therein by the electric sensing zone method comprises inner and outer steel tubes disposed one within the other to form an annular gas containing space, the tubes being spaced apart from one another by electrically insulating spacing rings between the two tubes at or adjacent to the opposite ends thereof. The space is vented to the exterior of the outer tube, or in the case of a one-shot probe to the interior of the inner tube. A sensing zone member, which may also act to space the tube lower ends, is mounted by the tubes at their lower ends and provides the sensing zone orifice. In some embodiments the seals between the sensing zone member and the tube lower ends are maintained despite differences in expansion coefficients of the materials.

Abstract: A probe for electrical contact with a metal layer of an integrated circuit wherein the probe features a polycrystalline diamond layer coating a fine conductive wire. The diamond coating has exposed pyramidal facets having a density of at least 2000 per square millimeter. The substrate has a radius exceeding one micrometer.

Abstract: Methods and apparatus for detecting and utilizing a voltage produced by a variety of materials for process control and analysis purposes.

Abstract: The device has a single strip having a first end, a second end, a length and a width. The first end of the strip is curved toward the second end of the strip to form a loop having a height. The length is approximately 10 mm, the width is approximately 5-8 mm, and the height is approximately 0.8-1.2 mm. The loop is preferably fabricated from copper. The loop is mounted directly to a test instrument such as a computer controlled impedance analyzer or network analyzer. The test instrument measures the inductance and resistance of the loop with no thin film sample placed therein, and then measures the inductance and resistance of the loop containing the sample under test. From these measurements, the device ultimately derives the permeability of the sample under test.

Abstract: Apparatus for measuring moisture content and bulk flow rate of cotton and other bulk materials, such as wool or wood chips, while they are being transported on a belt conveyor. The apparatus comprises resistance-sensing electrode fingers pendulously mounted over the conveyor, the movement of the resistance-sensing fingers being halted in their downward arcuate path by the sensed material. The weight of the electrode assembly presses the fingers against the material with uniform pressure. The angular displacement of the fingers about an axis of suspension is used as a measure of bulk flow rate.

Abstract: Apparatus for measuring the surface resistance and electrical resistivity of a homogeneous, resistive material sample includes a measuring cell having a sample location able to receive the sample and several electrodes in the form of knives placed on the same side of the sample and guided in an insulating block whose ends are positioned on the sample, the pressure necessary for establishing good electrical contacts between the electrodes and the sample being ensured by a shim which urges the electrodes toward the sample. A first pair of the electrodes make it possible to inject a current into a sample to be tested and a second pair of the electrodes make it possible to collect a voltage from the sample.

Abstract: A method for detecting extent of cross-linking of a high impedance polymer material during a pre-cure state, the method including: placing an insulated ground plane adjacent to the polymer material and substantially parallel to a sensor; applying a test signal through a sensor to the material and through a reference resistance; determining a voltage difference between the test signal applied to the material and the reference resistance as the reference voltage; and correlating the voltage difference as a relative indicator of the extent of cross-linking which has occurred within the polymer material. Also disclosed is a device for implementing the subject method.

Abstract: Disclosed is a method of and an apparatus for evaluating the reliability of metal interconnects. It is capable of performing the evaluation under such a testing condition as to reproduce an actual operating environment, that is, under the testing condition of simultaneously accelerating electromigration and stress-induced migration, thereby evaluating failures conventionally missed to be evaluated. In particular, this method is applicable for evaluating the reliability of metal interconnects of semiconductor devices, and which includes the steps of performing a constant-temperature storage test I for interconnect reliability evaluation at a temperature over a specified temperature for a specified time; and applying a current to the interconnect and simultaneously performing a test II of measuring a voltage of the interconnect.

Abstract: A method and an apparatus to electronically identify a page. Each page has a surface conductive trace that is coupled to an electronic circuit to measure the conductivity of the trace. The primary purpose of the conductive trace is to provide an identification for the page.

Abstract: A sensor and method for identifying the surface properties of a workpiece includes a microstrip sensor for transmitting and receiving microwave signals and surface properties determining means for determining the surface properties of the workpiece, including the type of material from which the workpiece is constructed, based upon the strength of the detected microwave signals. The surface properties identifying sensor also includes a microwave generator for producing microwave signals at a predetermined frequency for transmission by the microstrip sensor and a detector for detecting the microwave signals received by the microstrip sensor from the workpiece. Thus, workpieces comprised of a conductive material, an insulative material and a conductive material coated with a radar absorbing material can be readily distinguished by the surface properties identifying sensor and method.

Abstract: This invention embodies a method and apparatus for determination of surface resistivity (.rho.) of materials to be used for a desired purpose. The surface resistivity is obtained by measuring surface resistance (R) of at least one square area of the material, and converting the surface resistance into a surface resistivity (.rho.) by a correction factor K (K=.rho./R) whenever the total area of the material is greater than three square area. The surface resistance is measured by placing a pair of square electrodes, spaced from each other a distance equal to the side of the square, applying measuring voltage potential to the electrodes, and determining the surface resistance of said at least one square area. The surface resistivity of materials of any size can be obtained by multiplying the surface resistance value by a correction factor determined for the size of the material being investigated.

Abstract: A dosimeter with reproducible changes in .epsilon.', .epsilon.'', or their equivalent two parameter circuit representations, under a given treatment regime that correlate directly with changes in physical attributes of a material or fluid, such as strength, modulus or viscosity, is used to monitor the deterioration of the physical attributes of the material or fluid.

Abstract: An apparatus and a method for determining the water content of an oil-in-water emulsion is disclosed. The apparatus includes a first sensor for measuring the real part of specific admittance of the emulsion, a second sensor which acts as a temperature compensation device and electronic circuitry for producing a signal representative of the water content of the emulsion. The method for determining the water content comprises measuring the real part of specific admittance of an oil-in-water emulsion and providing a signal representative thereof, providing a reference signal indicative of the emulsion temperature, adjusting the measured real part of specific admittance signal with the reference signal and converting the adjusted signal into a current signal representative of the percentage water content of the emulsion.

Abstract: A molten metal inclusion sensor intended for "continuous" use in the testing of steel, i.e. a useful life of at least about 30 minutes, comprises a probe which is detachably connected to a water-cooled support member (35). The probe comprises a tube (30) of heat resistant material, preferably silica, having an inner electrode (31) mounted on its interior wall and an outer electrode (32) mounted on its exterior wall, the molten metal entering the tube interior through an orifice (33) upon its immersion in the molten metal, whereupon the flow of metal with entrained inclusions is monitored by measuring the voltage between the electrodes (31, 32). The electrodes (31, 32) are preferably of graphite and are shaped to fit closely against the walls of the part of the tube (30) that is immersed in the metal and are of a material that retains enough mechanical strength to support the tube (30) as the metal is pumped into and out of interior, the metal remaining hot enough for this pumping to occur.

Abstract: Apparatus for testing shelled corn in a combine storage tank during harvesting includes a plurality of charged electrodes each in the form of an elongated rod arranged in a spaced manner and positioned in a lower portion of the combine storage tank to be completely encompassed by the shelled corn. The electrodes are coupled to a moisture meter located in the combine cab allowing the operator to determine the moisture content of the corn crop at harvest. The moisture meter is easily disconnected from the electrodes and removed from the combine to permit moisture testing of corn kernels while still on the cob prior to harvest.

Abstract: A vapor electrical conductivity cell with sensing plates mounted on insulrs exposed to the vapor. Vapor condensation on those insulators cause errors in the conductivity measurements. The improvement of the invention keeps the insulators at a temperature higher than the vapor. The leakage errors are therefore reduced considerably.

Abstract: A device for the electric characterization of samples, comprises a UHF resonator intended to be coupled locally to the sample. The resonator is formed by a microstrip or triplate line loop (20) carried by a conducting plane (16) and having a gap of small length with respect to the length of the loop and an assembly (32) for receiving the sample in a position in which the sample is coupled selectively to the edges of the gap without being interposed therebetween. The edges of the gap of the loop are fixed to two electrodes of small area passing through a thin plate of dielectric material having a flat face for application against the sample.

Abstract: An apparatus for determining the percentages of individual components of a mixture having at least two components of different electrical conductivities, the apparatus having at least two sensors connectable across an a.c. voltage source, and being arranged such that the mixture being introducible therebetween, wherein each sensor has a pin electrode having a first sensing surface for electrical contact with the mixture, and a plate electrode having a second sensing surface electrically insulated from the mixture, wherein the area of the second sensing surface is larger than the area of the first sensing surface; the pin electrode and the plate electrode of each sensor are each connected to the same potential of the voltage source.

Abstract: Method and apparatus for the real time detection of the formation of ice on a surface in which a sensor having spaced electrodes along the surface is embedded in the surface for which detection is to be provided. Resistance between the electrodes is monitored and electrode temperature is monitored. When a sharp rise in resistance on the surface due to the presence of ice is detected at the same time that the surface temperature is at or below the freezing temperature of water, then a computer provides a signal to indicate the formation of ice.

Abstract: A diesel engine exhaust system is provided with a particulate trap for collecting the products of incomplete combustion during the engine power cycle. A sensing mechanism including an electrode downstream of the trap and a signal generating circuit provides a positive indication of occurrence of regeneration of the trap. Charged particles generated during regeneration induce a charge of the electrode, that charge activates the signal generating circuit and it, in turn, produces an indication external of the exhaust system that trap regeneration is occurring. That indication can be in the operator's compartment.