3507 results about "Electric resistivity" patented technology

In a first aspect, an MIM stack is provided that includes (1) a first conductive layer comprising a first metal-silicide layer and a second metal-silicide layer; (2) a resistivity-switching layer comprising a metal oxide layer formed above the first conductive layer; and (3) a second conductive layer formed above the resistivity-switching layer. A memory cell may be formed from the MIM stack. Numerous other aspects are provided.

Methods and devices for measuring the size of a body lumen and a method for ablating tissue that uses the measurement to normalize delivery of ablational energy from an expandable operative element to a luminal target of varying circumference are provided. The method includes inserting into the lumen an expandable operative element having circuitry with resistivity or inductance that varies according to the circumference of the operative element, varying the expansion of the operative element with an expansion medium, measuring the resistivity of the circuitry, and relating the resistivity or inductance to a value for the circumference of the operative element. In some embodiments the sizing circuit includes a conductive elastomer wrapped around the operative element. Other embodiments of the method apply to operative elements that include an overlapping energy delivery element support in which the overlap varies inversely with respect to the state of expansion, and which is configured with sizing electrodes that sense the amount of the overlap.

A method and apparatus for evaluating the resistivity of earth formations surrounding a borehole, particularly high-contrast thin-layer formations or at high dip angles. The method involves positioning a pair of transmitters and a pair of receivers within the borehole, the receivers or transmitters adhering to specific spacing limitations, alternately transmitting electromagnetic energy of a particular frequency and receiving voltage data associated with the transmitted energy. Multiple voltage data are acquired and a representation of a resistivity or conductivity profile is created from a formulated difference of the data from a particular depth and/or neighboring depths. The apparatus forms part of a well logging system including a well tool adapted to be moveable through a borehole. The apparatus being coupled to the well tool and adapted with means to input voltage data developed by the receivers disposed on the well tool. The apparatus further adapted with means for performing calculations to determine a conductivity profile and for recording the profile on an output record medium.

An electrosurgical working end for instant and automatic modulation of active Rf density in a targeted tissue volume. The working end of the probe of the present invention defines a tissue-engagement plane that is adapted to contact the targeted tissue. The cross-section energy delivery apparatus comprises (i) a conductive surface engagement plane for tissue contact, (ii) a substrate comprising a medial conductive matrix of a temperature sensitive resistive material; and (iii) an inner or core conductive material (electrode) that is coupled to an Rf source and controller. Of particular interest, the medial conductive matrix comprises a positive temperature coefficient (PTC) that exhibits very large increases in resistivity as it increases beyond a selected temperature, which is described as a switching range. The PTC material is selected and fabricated to define a switching range that approximates a particular thermally-mediated therapy. In a method of use, it can be understood that the engagement plane will apply active Rf energy to the engaged the tissue temperature elevates the medial PTC conductive layer to its switching range. Thereafter, Rf current flow from the core conductive to the engagement surface will be instantly modulated to maintain tissue temperature at the switching range. Moreover, the conductive matrix effectively functions as a resistive electrode to thereafter passively conduct thermal energy to the engaged tissue above its switching range. Thus, the working end can modulate the energy application to tissue between active Rf heating and passive conductive heating of the targeted tissue to maintain a targeted temperature level.

Methods of forming a transition metal containing film on a substrate by a cyclical deposition process are disclosed. The methods may include: contacting the substrate with a first vapor phase reactant comprising a transition metal halide compound comprising a bidentate nitrogen containing adduct ligand; and contacting the substrate with a second vapor phase reactant comprising a reducing agent precursor. The deposition methods may also include forming a transition metal containing film with an electrical resistivity of less than 50 μΩ-cm at a film thickness of less than 50 nanometers.

An electromagnetic wave propagation resistivity borehole logging system comprising multiple groups of electromagnetic transmitter-receiver arrays operating at three frequencies. The borehole logging tool component of the system employs eight transmitters and four receivers. The transmitters and receivers are disposed axially and symmetrically along the major axis of the tool to form four group pairs. Each group pair consists of a transmitter-receiver groups axially and symmetrically on opposing sides of a reference point on the tool. Each, transmitter-receiver group consists of one transmitter assembly and two receiver assemblies. Each transmitter-receiver group is operated at two of three operating frequencies which are 100 kHz, 400 kHz and 2 MHz. Some of the transmitter and receiver assemblies are fabricated to yield azimuthally focused resistivity measurements, and to yield vertical and horizontal resistivity in anisotropic dipping beds. The system can be embodied as a logging-while-drilling system or as a wireline logging system.

The invention relates to a graphene composite material and a preparation method thereof. The graphene composite material provided by the invention is characterized in that a graphene material plate fixed on a metallic matrix serves as a carrier, and the elementary substance and/or a compound are compounded on the graphene surface. Meanwhile, the invention also discloses a method for preparing the graphene composite material. The graphene composite material prepared by the invention is opened between graphene sheets and is compounded with a chemical substance under the condition that a space body structure is formed, and the obtained material has high conductivity, high specific surface area and excellent performance of low electrical resistivity between the sheets, and can be widely applied to the fields of energy storage materials such as lithium ion batteries, super-capacitors, super lead carbon batteries, super nickel-carbon electrodes, solar energy and fuel cells, the field of heat dissipation materials, the field of environment-friendly adsorbing materials, the field of sea water desalination materials, the field of photoelectric sensor materials, the biological relevance field, the field of catalyst materials and the fields of conductive ink and coating materials.

The invention relates to a method for manufacturing a semiconductor on insulator type substrate for radiofrequency applications, comprising the following steps in sequence: (a) provision of a silicon substrate (1) with an electrical resistivity of more than 500 Ohm·cm, (b) formation of a polycrystalline silicon layer (4) on said substrate (1), said method comprising a step between steps a) and b) to form a dielectric material layer (5), different from a native oxide layer, on the substrate (1), between 0.5 and 10 nm thick.

A high energy density, high power density capacitor having an energy density of at least about 0.5 J/cm3 is provided. The capacitor comprises a plurality of interleaved metal electrode layers separated by a polymer layer. The interleaved metal electrode layers terminate at opposite ends in a solder termination strip. The high energy density aspect of the capacitors of the invention is achieved by at least one of the following features: (a) the dielectric thickness between the interleaved metal electrode layers is a maximum of about 5 mu m; (b) the polymer is designed with a high dielectric constant kappa of at least about 3.5; (c) the metal electrode layers within the polymer layer are recessed along edges orthogonal to the solder termination strips to prevent arcing between the metal electrode layers at the edges; and (d) the resistivity of the metal electrode layers is within the range of about 10 to 500 ohms per square, or a corresponding thickness of about 200 to 30 ANGSTROM .

An implantable device that contains a power source, a device for producing electrical signals, and a conductor assembly for communicating the electrical signals to biological matter. The conductor assembly contains of a conductor that is capable of being flexed at least about 15 degrees and that has a resistivity at 20 degrees Centigrade of from about 1 to about 100 micro ohm-centimeters. The conductor assembly also contains a magnetic shield located above the flexible conductor; the magnetic shield contains an antithrombogenic composition. The magnetic shield also contains a magnetic shielding material that has a magnetic shielding factor of at least about 0.5.

The invention is characterized in that it comprises a truncated contact lens (1), whose truncation plane is parallel to the base of said contact lens, and a polymeric nanocomposite material (2) centrally disposed and attached to the perimeter of the truncated area, said material being sensitive to pressure changes, biocompatible and transparent, and including contact electrodes (3), and in that it also comprises means for transmitting IOP measurement data to an external system. The invention also relates to a method for measuring IOP using said lens comprising: i) placing said sensor contact lens in the eye to determine its intraocular pressure; ii) providing a direct current value between external electrodes; iii) ΔV measurement between internal electrodes; and iv) identifying whether the value obtained is outside the linear response, expressed in changes of resistivity, of the polymeric nanocomposite material. The invention also relates to a telemetry system comprising said lens.

The present inventions are directed to touch sensors with improved topological equivalence between an equipotential space and a Cartesian space to which the equipotential space will be mapped. The touch sensor comprises a substrate with a touch region, and a set of electrodes that are electrically coupled to the touch region. The touch sensor further comprises a plurality of resistive band segments that frames the touch region. The electrodes are located between the resistive band segments. Each resistive band segment has a resistivity that is intermediate between the resistivity of the electrodes and the resistivity of the touch region, thereby providing a transition between the low resistivity electrodes and the high resistivity touch region, and improving the topological equivalence within the corners of the touch region. At least one of the band segments has a non-uniform linear resistance to provide further improvement to the topological equivalence.

A method and apparatus for obtaining a resistivity measurement of an earth formation surrounding a borehole in an MWD device uses an electrode for injecting current into the earth formation and an electrode for obtaining a responsive signal from the borehole. The electrodes are located on the drill bit arm or blade. Measured resistivity values are obtained at the location of the drill bit. Measurements can be taken in both oil-based mud and water-based mud environments. Maximum or minimum resistivity can be used to best represent the resistivity of the surrounding formation.

A GaN-based high electron mobility transistor (HEMT) has an undoped GaN layer where a two-dimensional electron gas layer is formed, the undoped GaN layer having a high electric resistivity enabling a pinch-off state to be obtained even when the gate bias voltage is 0 V. The GaN-based HEMT comprises a semi-insulating substrate on which a GaN buffer layer is formed. An undoped GaN layer is disposed on the GaN buffer layer and has an electric resistivity of not less than 1x106 OMEGA/cm2. An undoped AlGaN layer is disposed on the undoped GaN layer via a heterojunction such that an undercut portion is formed therebetween. An n-type GaN layer is further disposed in such a manner as to bury side portions of the undoped AlGaN layer and the undercut portion. The individual layers thus Ad form a layered structure. A gate electrode G is formed on the undoped AlGaN layer, and a source electrode S and a drain electrode D are formed on the n-type GaN layer.

The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more antennas, at least two of the antennas having a transversely-sensitive element and an axially-sensitive element is provided. Azimuthally-sensitive measurements are obtained using the antennas of the downhole logging tool. The measurements are fitted to a Fourier series having Fourier coefficients that include channel gains, if any. A DC component, a first harmonic component, and a second harmonic component are determined from the Fourier series, a measurement type is determined using the DC component, the first harmonic component, and/or the second harmonic component, and the formation property of the subsurface formation is determined using the determined measurement type.

A bio-electrode for detecting heart signals and the like comprises a dry electode surface having an elevated resistivity to reduce the effect of polarization noise. The electrode is combined with a circuit having an external discharge resistor across which an output signal is obtained wherein the discharge resistor has a value which reduces the time constant of polarization noise to less than one second.

Apparatus for sensing and characterizing particles (e.g., blood cells or ceramic powders) suspended in a liquid medium comprises a conduit through which the particle suspension is caused to pass simultaneously with an electrical current. According to the invention, the interior wall of the conduit effectively varies in resistivity along the length of the conduit to define a delimited central region of high electrical resistivity which is smoothly contiguous on its opposing boundaries to uninsulated distal elements of lesser electrical resistivity. The delimited central region of the conduit functions as a Coulter volumeter conduit. The uninsulated distal elements of the conduit are made to have a dimension along the conduit wall which is at least equal to the axial extent of the effective ambit electric fields of a traditional Coulter volumeter conduit having a cross-sectional geometry identical to that of the delimited central region of high resistivity in the improved volumeter conduit. According to a preferred embodiment of the invention, the delimited central region of the improved volumeter conduit is defined by a traditional Coulter conduit wafer, i.e., a dielectric wafer containing a central circular conduit, and the distal elements of lesser resistivity are defined by uninsulated, electrically conductive, circular collars attached to opposite sides of the conduit wafer. The conduit in the conduit wafer and the openings in the conductive collars collectively form a hydrodynamically smooth volumeter conduit, in which the electric and hydrodynamic fields of the traditional volumeter conduit are advantageously amended in the manner above noted.

A mapping and ablation catheter with contact force sensing capabilities at a distal end, includes a catheter body, a deflectable section, and a tip distal section which has a tip electrode and a contact force sensor for sensing a 3D contact force vector applied to the tip electrode. In contact with the tip electrode, the contact force sensor has a body and has at least one sensor with an electrical characteristic that is responsive to deformation of the body resulting from force vector. The sensor is adapted to receive an electrical current and to output an electrical signal indicative of a change in the electrical characteristic. In one embodiment, the sensor is a strain gage responsive to tension and compression of at least a portion of the body of the force sensor and the electrical characteristic of the strain gage that is monitored is electrical resistivity. In another embodiment, the sensor is responsive to strain and stress of at least a portion of the body, and the electrical characteristic being monitored is inductance or hysteresis loss.