Schlumberger Technology Corporation

Tdk Corporation

Nec Laboratories America, Inc.

Daniel R Hines

Oliver Clinton Mullins

Stuart A Solin

Kambiz A Safinya

Tao Zhou

Masaru Niwa

Paul Simon Hammond

Tineke Thio

Ralphe Wiggins

Jonathan E Moussa

Lakshminarayanapuram Ramdas Ram-Mohan

John M Sullivan, Jr

Stephen P Cramer

Jeffrey Tarvin

Stephen Garoff

Noboru Wada

This invention relates to a method and system for finite element modeling of enhanced magnetoresistance in thin film semiconductors containing at least one metallic inclusion therein. The method and system utilizes finite element analysis techniques as a function of the applied magnetic field and the geometry of the device for comparing the device characteristics with predetermined qualities and modifying the device to achieve a correlation between the device characteristics and the predetermined qualities.

Method and system for finite element modeling and simulation of enhanced magnetoresistance in thin film semiconductors with metallic inclusions

A symmetric van der Pauw disk of homogeneous nonmagnetic semiconductor material, such as indium antimonide, with an embedded concentric conducting material inhomogeneity, such as gold, exhits room temperature geometric extraordinary magnetoresistance (EMR) as high as 100%, 9,100% and 750,000% at magnetic fields of 0.05, 0.25 and 4.0 Tesla, respectively. Moreover, for inhomogeneities of sufficiently large cross section relative to that of the surrounding semiconductor material, the resistance of the disk is field-independent up to an onset field above which the resistance increases rapidly. These results can be understood in terms of the field-dependent deflection of current around the inhomogeneity. The EMR exhibited by a composite van der Pauw sensor comprising a semiconductor having an embedded metallic inhomogeneity or internal shunt can be obtained from electrically equivalent externally shunted structures, such as rectangular plates including an external conductive shunt element which is simple to manufacture in the mesoscopic sizes required for important magnetic sensor applications. For example, a bilinear conformal mapping is used to transform a circular composite van der Pauw disk sensor having an embedded conducting inhomogeneity into a corresponding externally shunted rectangular plate structure. The result is an EMR sensor that can be realized in very simple structures which facilitate fabrication in mesoscopic dimensions important for many magnetic sensor applications.

Extraordinary magnetoresistance at room temperature in inhomogeneous narrow-gap semiconductors

Methods for quantifying the oil and water fractions of a fluid stream. A first method broadly includes making optical density (OD) measurements of the fluid stream by detecting photons of a first predetermined energy where the oil and water absorption characteristics are substantially identical (e.g., 1710 nm wavelength), and determining the oil and water fractions f.sub.o and f.sub.w according to OD.perspectiveto.f.sub.w .alpha..sub.w l+f.sub.o .alpha..sub.o l where .alpha..sub.w and .alpha..sub.o are related to the absorption coefficients of the oil and water at the predetermined energy, l is the path width of the fluid stream, and f.sub.w +f.sub.o =1. A second method which eliminates scattering effects utilizes the photons at the first predetermined energy and further utilizes photons of a second predetermined energy which is sufficiently close to the first predetermined energy such that the oil fraction is a linear function of the OD over the energy range. The oil and water fractions are then determined from the difference in optical density values (.DELTA.OD) according to .DELTA.OD=f.sub.o [(OD.sub.o,a -OD.sub.o,b)- (OD.sub.w,a -OD.sub.w,b)]+(OD.sub.w,a -OD.sub.w,b), where OD.sub.o,a, OD.sub.o,b, OD.sub.w,a, and OD.sub.w,b are the optical densities per unit length of pure oil (o) and pure water (w) at the first (a) and second (b) wavelengths.

Method of analyzing oil and water fractions in a flow stream

A borehole apparatus detects the presence of gas within a formation fluid sample. A light source transmits light rays to an interface between the fluid sample and the flow line. The interface reflects the light rays toward a detector array. The detector array detects light rays having angles of incidences extending from less than the Brewster angle to more than the critical angle for gas. A data base stores information concerning the Brewster angle and critical angle of gas for a plurality of gas volume categories. A processor determines the percentage of gas present in the formation fluid sample and categorizes the fluid sample as high as, medium gas, low gas, and no gas based on the signal from the detector array and the information from the data base.

Apparatus and method for detecting the presence of gas in a borehole

A borehole apparatus detects the presence of gas within a formation fluid sample. A light source transmits light rays to an interface between the fluid sample and the flow line. The interface reflects the light rays toward a detector array. The detector array detects light rays having angles of incidences extending from less than the Brewster angle to more than the critical angle for gas. A data base stores information concerning the Brewster angle and critical angle of gas for a plurality of gas volume categories. A processor determines the percentage of gas present in the formation fluid sample and categorizes the fluid sample as high gas, medium gas, low gas, and no gas based on the signal from the detector array and the information from the data base.

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Lawrenceville, NJ, United States of America

Daniel R Hines