352 results about "Potential measurement" patented technology

Interelectrode impedance or electric field potential measurements are used to determine the relative orientation of one lead to other leads in the spinal column or other body/tissue location. Interelectrode impedance is determined by measuring impedance vectors. The value of the impedance vector is due primarily to the electrode-electrolyte interface, and the bulk impedance between the electrodes. The bulk impedance between the electrodes is, in turn, made up of (1) the impedance of the tissue adjacent to the electrodes, and (2) the impedance of the tissue between the electrodes. In one embodiment, the present invention makes both monopolar and bipolar impedance measurements, and then corrects the bipolar impedance measurements using the monopolar measurements to eliminate the effect of the impedance of the tissue adjacent the electrodes. The orientation and position of the leads may be inferred from the relative minima of the corrected bipolar impedance values. These corrected impedance values may also be mapped and stored to facilitate a comparison with subsequent corrected impedance measurement values. Such comparison allows a determination to be made as to whether the lead position and/or orientation has changed appreciably over time. In another embodiment, one or more electrodes are stimulated and the resulting electric field potential on the non-stimulated electrodes is measured. Such field potential measurements provide an indication of the relative orientation of the electrodes. Once known, the relative orientation may be used to track lead migration, to setup stimulation configurations and parameters for nominal stimulation and/or navigation. Also, such measurements allow automatic adjustment of stimulation energy to a previously-defined optimal potential field in the case of lead migration or postural changes.

An active implantable medical device, in particular a pacemaker, defibrillator or cardioveter of the multisite type, including a circuit for measuring intercardiac impedance. Electrodes are placed in at least one ventricular site and one atrial site, and are connected to a circuit for the collection of cardiac signals, to detect a depolarization potential, as well as to a stimulation circuit, to apply stimulation pluses to at least some of the aforementioned sites. The measurement of a trans-pulmonary bio-impedance is obtained by injecting a current from an injection circuit (16) between the case (18) of the device and a first atrial (RA-) (or ventricular) site, and measuring a differential potential (20) between the case (18) and a point of measurement located in a second atrial (RA+) (or ventricular) site using a collection circuit. Switches are selectively operable to isolate the case (18) from the current injection and measurement of potential circuits, and to connect them to a common reference potential site, atrial or ventricular (LV-), which is distinct from the sites (RA-,RA+) to which are also connected these circuits, so as to allow a measurement of intracardiac impedance from the signal delivered by the differential potential measuring circuit. The switching is obtained by connections to an electric ground, operating independently of the current injection circuit and the differential potential measuring circuit.

The invention relates to devices and methods for nanopore sequencing. The invention includes arrays of nanopores having incorporated electronic circuits, for example, in CMOS. The invention includes devices having sample and reference pores connecting sample, measurement and reference chambers, wherein potential measurements in each chamber is used to provide an accurate determination of current through a sample nanopore, improving nanopore sequencing.

Abstract of the Disclosure

An electrochemical cell has two terminals. One of the terminals is connected to a pulse-width-modulated (PWM) power supply and to a voltmeter. The other terminal is connected to circuitry capable of switching between amperometric and potentiometric measurement modes. A sequence of successive approximations permits selection of a PWM duty cycle giving rise to a desired voltage at the terminal connected with the power supply. In this way a stable excitation voltage is supplied to the cell even in the face of supply voltage instability or drift or instability in electronics coupled with the cell.

An insulation resistance determining system (50) comprises an insulation resistance determining portion configured by connecting a coupling capacitor (52), a detection resistor (54), and a pulse oscillating circuit (56) in series with a common mode potential measuring point (30), and an insulation resistance determining portion having a filter (58) which processes an AC signal (v_x) at a junction between the coupling capacitor (52) and the detection resistor (54), an amplifier (60), a wave-peak value detection circuit (62), and a controller (70). The controller (70) has functions for detecting a drop in insulation resistance in response to an output of the wave-peak value detection circuit (62); for requesting an HVCPU (40) to change the common mode potential so as to determine a failure of the insulation resistance determining portion; and for determining a failure of the insulation resistance determining portion from an output change of the wave-peak value determining circuit (62) between before and after the common mode potential change.

The present teachings relate to the application of electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by a layer-by-layer (LbL) technique or other techniques and mounted with electrodes along their boundaries. The response of the thin films to various stimuli determined by relying on electric current excitation and corresponding boundary potential measurements. The spatial conductivity variations are reconstructed based on a mathematical model for the EIT technique. Here, the ability of the EIT method to provide two-dimensional mapping of the conductivity of CNT thin films is validated by (1) electrically imaging intentional structural defects in the thin films and (2) mapping the film's response to various pH environments.

The invention relates to a method for evaluating the new energy development potential of regional power grids based on power generation absorption. New energy power characteristics are described from the level of new energy output power parameters, and power grid structure constraints are described from the level of power grid load flow calculation parameters. Based on a sequential production simulation method, by establishing a multi-period load flow optimization evaluation model and adopting matlab software for programming simulation calculation, a corresponding new energy receptivity evaluation model is established with the power generation of new energy units as the objective function and the new energy wind curtailment/light curtailment rate as the constraint. The new energy development degree of the regional power grids is comprehensively measured, visual development potential measurement indexes are obtained finally, and the new energy receptivity trend of the regional power grids is analyzed in a drawing mode. The power generation of the power grids by renewable energy absorption is simply and visually calculated, and reasons for the insufficient new energy receptivity of the power grids are analyzed. The economy and safety of power grid operation are analyzed based on various operation scenes, and the new energy receptivity of the power grids under various scenes is studied.

A potential measurement apparatus for measuring a surface potential of an object of measurement detects a change in electric charge induced at a detection electrode due to electrostatic induction by changing a distance between the detection electrode and the object of measurement in accordance with a predetermined period, using a neutral distance as reference, as a signal representing a change in electric current. The potential measurement apparatus includes a first detection unit for detecting a signal representing a fundamental period of the change in electric current and a signal representing a second harmonic period, a second detection unit for detecting information representing a capacitance between the detection electrode at the neutral distance and the object of measurement and an arithmetic unit for computationally obtaining information on the surface potential of the object of measurement, with eliminating an influence of the neutral distance and the capacitance, according to an outcome of detection of the first detection unit and an outcome of detection of the second detection unit.

An electrophysiological measurement method and system is provided for positioning an implantable transducer of a hearing instrument relative to a middle ear component or inner ear of a patient. The method and system employ electrophysiological measurement signals obtained in response to test signals applied to an implanted transducer. In one embodiment, the electrophysiological measurements are obtained by an electrocochleography measurement device that measures the cochlear summating potential and/or action potential responsive to test signals applied to an implanted transducer. In another embodiment, an auditory brainstem response measurement device is utilized to obtain electrical potential measurement signals responsive to test signals applied to an implanted transducer.

An image forming apparatus includes an image carrier for carrying a toner image and a transfer device. In the transfer device, a voltage applier applies a predetermined voltage to a transfer electric field generator. A potential measurement device measures a surface potential of the transfer electric field generator when a predetermined time period elapses after the voltage applier applies the predetermined voltage to the transfer electric field generator. A controller determines a transfer bias to be applied by at least one transfer member to the transfer electric field generator based on the measured surface potential of the transfer electric field generator. The at least one transfer member applies the transfer bias to the transfer electric field generator to generate a transfer electric field. The toner image is transferred from the image carrier onto a toner image receiver by the transfer electric field generated by the transfer electric field generator.

A method for determining the influence of one of a plurality of cathodic protection circuits along a pipeline includes switching one of a plurality of cathodic protection circuits off, while the remainder of the plurality of cathodic protection circuits are left on, with a portable pipe-to-soil potential measurement unit measuring the pipe-to-soil potential along the pipeline. From these measurements, a calibration curve is generated and an apparatus for monitoring the cathodic protection circuits is strategically positioned on the pipeline. The apparatus includes a remote monitoring unit having a pipe-to-soil potential measurement unit for measuring the potential between the ground bed and pipeline. The remote monitoring unit is off except while making measurements. The remote monitoring unit may optionally include a pipeline current measurement unit connected at a second connection point on the pipeline for measuring the current passing through the pipeline between the first and second connection points.

A reference potential adjusting apparatus is provided. The reference potential adjusting apparatus includes a reference potential measuring unit configured to measure a potential of a solution, a counter electrode disposed in the solution, and configured to change the potential of the solution through oxidation-reduction reactions with the solution, and a comparator configured to compare a measurement voltage provided by the reference voltage measuring unit to a reference voltage provided by a reference voltage supply unit, and to adjust reactions of the counter electrode with the solution according to the result of the comparison. The reference potential measuring unit includes a reference electrode, a common electrode disposed to be spaced apart from the reference electrode, and at least one nano structure contacting the reference electrode and the common electrode, and having electrical conductivity changing according to the potential of the solution.

The invention relates to optical sensor measurement methods that use a swept wavelength optical source to determine wavelength shift as well as to optical sensor systems that embody and employ these methods. A variable scan rate swept optical source is used to determine the optical path length from the optical interrogator to the optical sensors being measured. This data can then be used as desired or needed in implementing the sensor or making sensor measurements. In particular the data can be used in the optical sensor system to compensate for potential measurement errors due to the finite speed of light in the optical medium interconnecting optical sensors under test.

A potential sensor (101) including first and second detection electrodes (121 a, b) opposed to an object of which a potential is to be measured, and a movable shutter (125) so positioned between the detection electrodes and the potential-measured object with gaps thereto; wherein the movable shutter can assume a first state and a second state, the first detection electrode is exposed to the potential-measured object wider when the movable shutter assumes the first state than when the movable shutter assumes the second state, and the second detection electrode is exposed to the potential-measured object narrower when the movable shutter assumes the first state than when the movable shutter assumes the second state.

Damage and usage conditions in the vicinity of fasteners in joined structures are nondestructively evaluated using the fasteners themselves. Sensors or sensor conductors are embedded in the fasteners or integrated within the fastener construct, either in the clearance gap between the fastener and the structure material or as an insert inside the shaft or pin of the fastener. The response of the material to an interrogating magnetic or electric field is then measured with drive and sense electrodes both incorporated into the fastener or with either drive or sense electrodes external to the fastener on the material surface. In another configuration, an electric current is applied to one or more fasteners and the electric potential is measured at locations typically between the driven electrodes applying the current. The potential is measured circumferentially around the fastener at locations on the material surface or across pairs of fasteners throughout or along the joint. The voltage or potential measurement electrodes may be collinear with the drive electrodes. State sensitive material layers can be added either to the fastener or the test material layers in order to enhance observability of the test material condition, such as the presence of a crack, mechanical stress, delamination, or disbond.

The present invention relates to an apparatus for monitoring the progress of membrane fouling that occurs on pores as well as on the surface of a membrane by means of variations of zeta potential (zeta) of a hollow-fiber membrane according to time passage of filtration of a suspension, wherein colloid particles, biopolymers and other inorganic particles are dispersed, and the method thereof. Moreover, the present invention also relates to a method to identify the effect of concentration polarization layer and cake layer which can vary according to the axial position of a hollow-fiber and the developing progress of a membrane fouling by measuring the position-dependent zeta potential of the hollow-fiber membrane.

The invention belongs to the technical field of the stainless steel material pitting evaluation, particularly to an ultrasonic electrochemical method for correctly evaluating the stainless steel pitting potential, including: adopting the cleaning action of the ultrasonic electrolytic cell in the pitting growing process to remove the pitting cover mass inhibiting the solution diffusing formed on the surface of the pit, eliminating the data dispersion on the pitting potential and the pitting repassivation caused by the ion diffusion related with the pitting cover porosity, which is favorable to obtaining the unique pitting potential irrespective of the surfacing state of the stainless steel material. The invention is of important use value to correctly and fast evaluate the pitting resistant performance of the stainless steel and research the pitting mechanism of the stainless steel.