363 results about "Current density distribution" patented technology

A single mode high power laser device such as a VCSEL is formed with two oxide apertures, one on each side of the active region or cavity. The sizes of the apertures and the distances from the apertures to the cavity center are chosen or optimum, near-Gaussian current density distribution. The high power of a VCSEL thus formed is improved still more by good heat removal by either formation of a via through the substrate and gold plating on top and bottom of the VCSEL (including the via) or by lifting the VCSEL structure from the substrate and locating it on a heat sink.

A spin valve device includes a non-magnetic enhancement layer adjacent an ultra thin free layer. The thickness of the free layer may be less than the mean free path of a conduction electron through the free layer. The GMR ratio is significantly improved for free layer thicknesses below 50 Å. The enhancement layer allows electrons to travel longer in their spin state before encountering scattering sites. The electronic properties of the enhancement layer material can be matched with the adjacent free layer without creating a low resistance shunt path. Because the free layer may be made ultra thin and the enhancement layer is formed of a nonmagnetic material, less magnetic field is required to align the free layer, allowing for improved data density. Also, the enhancement layer allows for effective bias point control by shifting sensor current density distribution.

According to one embodiment, a high-frequency magnetic field-assisted magnetic recording head includes a main pole adapted for producing a writing magnetic field, a STO positioned above the main pole, a low-resistance layer positioned above the STO, and a current confinement layer positioned between the low-resistance layer and the main pole, wherein the main pole and the low-resistance layer are adapted for acting as poles for writing data to a magnetic medium in response to a flow of current to the STO positioned therebetween to generate a high-frequency magnetic field which overlaps with the writing magnetic field, and wherein the current confinement layer is adapted for controlling a current density and / or a current density distribution of the current flowing to the STO. Other magnetic recording heads and methods of production thereof are also described according to more embodiments.

The invention relates to a novel semiconductor light-emitting diode, which comprises a substrate, a buffer layer, an N-type layer, an active layer, an electronic barrier layer, a P-type layer and a P-type contact metal layer. The P-type layer, the electronic barrier layer, the active layer and the like are penetrated through etching; an N-type layer material is exposed to one side of a P-type material directly, and an N-type contact metal and an electrode are covered on an exposed area, so that the diffusion of transverse current in the N-type layer is enhanced; and simultaneously, a P-type metal covers an integral P-type semiconductor layer, and an LED emits light from the bottom surface of the substrate. Through the improvement, the transverse diffusion distance of the current in LED devices is shortened substantially, uneven distribution of current density in the LED devices due to current congestion is prevented, so that the LED devices emit the light uniformly, and the shading effect of a P-type electrode is eliminated.

In one embodiment, a sub-pad assembly of metal structures is located directly underneath a metal pad. The sub-pad assembly includes an upper level metal line structure abutting the metal pad, a lower level metal line structure located underneath the upper level metal line structure, and a set of metal vias that provide electrical connection between the lower level metal line structure located underneath the upper level metal line structure. In another embodiment, the reliability of a C4 ball is enhanced by employing a metal pad structure having a set of integrated metal vias that are segmented and distributed to facilitate uniform current density distribution within the C4 ball. The area1 density of the cross-sectional area in the plurality of metal vias is higher at the center portion of the metal pad than at the peripheral portion of the planar portion of the metal pad.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery and a membrane thereof. The membrane comprises a base membrane, wherein at least one surface of the base membrane is coated with a polymer coating; and the polymer coating is prepared into slurry by mixing and stirring a polymer, an adhesive agent and a pore forming agent in a solvent, coated on the surface of the base membrane, and uniformly distributed in an island shape. Compared with the prior art, the polymer coating in the membrane has good liquid absorption swelling capacity; an interface has good stability; the prepared lithium ion battery has an excellent mechanical property; an island-shaped distribution characteristic of the polymer coating provides a space for charging and discharging of a pole piece as well as swelling in a cycle process; and the problem of deformation of the lithium ion battery is well solved. In addition, the island-shaped polymer coating formed by the pore forming agent can be uniformly distributed on the base membrane, so that nonuniform current density distribution can be effectively avoided, and an influence on a property of the battery can be prevented.

A lateral injection VCSEL comprises upper and lower mirrors forming a cavity resonator, an active region disposed in the resonator, high conductivity upper and lower contact layers located on opposite sides of the active region, upper and lower electrodes disposed on the upper and lower contact layers, respectively, and on laterally opposite sides of the upper mirror, and a current guide structure including an apertured high resistivity layer for constraining current to flow in a relatively narrow channel through the active region, characterized in that a portion of the lower contact layer that extends under the top electrode has relatively high resistivity. This feature of our invention serves two purposes. First, it suppresses current flow in parallel paths and, therefore, tends to make the current density distribution in the aperture more favorable for the fundamental mode. Second, it reduces parasitic capacitance.

A system and method for current steering a neurostimulation signal is provided. The system and method provide a lead coupled to an implantable pulse generator (IPG). The lead may include a plurality of electrodes. The lead may be configured to be implanted at a target position proximate to tissue of interest. The system and method program the IPG to deliver at least a first pulse train to a first electrode and a second pulse train to a second electrode. The first and second pulse trains are interleaved with one another such that the first and second pulse trains form an activation current density distribution steered to overlay the tissue of interest.

Techniques for uniformity tuning in an ion implanter system are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for ion beam uniformity tuning. The method may comprise generating an ion beam in an ion implanter system. The method may also comprise measuring a first ion beam current density profile along an ion beam path. The method may further comprise measuring a second ion beam current density profile along the ion beam path. In addition, the method may comprise determining a third ion beam current density profile along the ion beam path based at least in part on the first ion beam current density profile and the second ion beam current density profile.

A cardiac magnetic field diagnostic apparatus for evaluating intracardiac three-dimensional localization of a myocardial injury by means of cardiac magnetic field measurement and a three-dimensional localization evaluating method of myocardial injury are disclosed. A magnetic field distribution measuring instrument (1) creates magnetic field distribution data by contactless magnetic field measurement on coordinates on the breast of a subject. An arithmetic operation unit (2) computers intracardiac three-dimensional current density distribution data from the magnetic field distribution data, draws a magnetic field integral cubic diagram as a cardiac contour cubic diagram according to the three-dimensional current density distribution data, creates data to draw the three-dimensional distribution of the QRS difference, the T-wave vector, or the RT dispersion of the same subject according to the three-dimensional current density distribution data, and reconstructs it on the cardiac contour. With this, evaluation of three-dimensional localization of a myocardial injury is possible.

The invention relates to a device and a method for measuring voltaic arc pressure distribution and current density distribution, belonging to the technical field of voltaic arc testing. The device comprises a motor, a positioning frame, a guide rail fixed on the positioning frame, a sliding element mounted on the guide rail, a welding torch position regulating mechanism arranged at the lower end of the sliding element, a flat table surface arranged below the positioning frame, a container positioned on the flat table surface, anode plates arranged in the container, and a weighting sensor. During the measurement, the motor drives a guide screw to rotate so as to further drive a welding torch to move along a direction vertical to an insulating material. The values of voltaic arc force and voltaic arc current which are applied on the two anode plates are collected. Then, a mathematic model, which is about the value of the voltaic arc force and circle domain pressure distribution of the voltaic arc and about the value of the voltaic arc current and circle domain current density distribution of the voltaic arc, is established. Solving is carried out next. Then, curves about the circle domain pressure distribution and the circle domain current density distribution of the voltaic arc can be drawn. The device and the method realize the simultaneous measurement of the microcosmic voltaic arc pressure distribution and the microcosmic voltaic arc current density distribution. In addition, the device has a simple production process, and the testing steps are simple.

A phase change memory cell and methods of fabricating the same are presented. The memory cell includes a variable resistance region and a top and bottom electrode. The shapes of the variable resistance region and the top electrode are configured to evenly distribute a current with a generally hemispherical current density distribution around the first electrode.

The invention relates to a multifunctional fuel cell on-line testing printed circuit board. The multifunctional fuel cell on-line testing printed circuit board is used for testing the partition electric density distribution, partition temperature distribution and partition alternating current impedance, of a fuel cell on line and comprises a partition flow field layer, a temperature testing layer, an impedance testing layer, an electric current density testing layer and an electrical current collection and water flow field layer which are sequentially arranged, wherein the partition flow field layer is connected with the fuel cell and is used for dividing the fuel cell into a plurality of mutually insulated partitions; and the partition flow field layer, the impedance testing layer, the current density testing layer, the current collection and the water flow field layer and the fuel cell are sequentially connected to form a closed loop circuit. Compared with the prior art, the multifunctional fuel cell on-line testing printed circuit board can accurately reflect the water-heat distribution, electrochemical reaction condition and mass and heat transfer phenomenon of each partition in the fuel cell by measuring the current density distribution, temperature distribution and alternate current impedance in the fuel cell, is integrally designed, is independent of an tested object completely, simple in structure and convenient to operate, can comprehensively reflect the performance of the partitions of the fuel cell.

The current density profile in the conduction channel of a field effect transistor is controlled and thermal gradients are limited under extreme operating conditions by providing lateral resistive ballasting at the source / drain regions adjacent the conduction channel. A distributed resistance is formed by inhibiting conversion of a region of deposited salicide from a high resistance phase state to a low resistance phase state through formation of the deposit with a width or area less than a critical dimension.

A method for non-invasive mapping (imaging) of the electrical impedance of an object. The present invention provides a method, current density impedance imaging (CDII) which produces an impedance image of object by measuring current density distributions and directly calculating the local impedance values. The method includes making measurements of at least two current density vector fields, J1 and J2, within a region of interest in an object and then calculating the logarithmic gradient of local conductivity, ∇ ln σ(x,y,z), using a formula∇ln⁢⁢σ=⁢(∇×J2)·(J1×J2)J1×J22⁢J1+⁢(∇×J1)·(J2×J1)J1×J22⁢J2+⁢(∇×J1)·J2J1×J22⁢J1×J2(1)where {right arrow over (J)}1(x,y,z) and {right arrow over (J)}2(x,y,z), are the pair of measured nonparallel current densities at point (x,y,z) and ∇ denotes the gradient operator.

Methods are provided for calibrating an ion beam scanner in an ion implantation system, comprising measuring a plurality of initial current density values at a plurality of locations along a scan direction, where the values individually correspond to one of a plurality of initial voltage scan intervals and one of a corresponding plurality of initial scan time values, creating a system of linear equations based on the measured initial current density values and the initial voltage scan intervals, and determining a set of scan time values that correspond to a solution to the system of linear equations that reduces current density profile deviations. A calibration system is provided for calibrating an ion beam scanner in an ion implantation system, comprising a dosimetry system and a control system.

The invention discloses a gradient coil design method with combination of a fonctionelle and a simulated annealing algorithm. The method is characterized by comprising the steps that firstly, a primary function of a stream function is built according to the framework shape of a gradient coil; secondly, the fonctionelle is built according to preset parameters, the extreme value of the fonctionelle is solved, and current density distribution is obtained; thirdly, a target function is built for an actual coil structure, the initial solution obtained for solving the extreme value of the fonctionelle is further optimized through the simulated annealing algorithm, and the obtained result is the basis of finial gradient coil wiring. Compared with an existing gradient coil design method which only adopts the simulated annealing algorithm, the efficiency is higher, it is ensured that the global optimum solution is searched for and obtained, and the performance of the designed gradient coil is improved. According to the design scheme, the method is suitable for all gradient coil types designed through the stream function method.

An MRI RF coil that is optimized for SENSE imaging is used in a method where the surface current density distribution on a coil former was calculated to maximize the SNRsense within a volume of interest. An analytic relationship was formulated between the SNRsense and surface current density on the coil former. The SNR at pixel ρ in a SENSE-MR image, SNRsense,ρ, is inversely proportional to the g-factor The g-factor was formulated in terms of the B1 distribution of the coils. By specifying the geometry of the desired coil former and using a finite element mesh, the surface current distribution was calculated to maximize the SNRsense, by minimizing (1 / SNRsense) in the volume of interest using a least squares procedure. A simple two-coil array was tested and phantom images were collected. The results show that the new coil design method yielded better uniformity and SNR compared to standard coils.

The current invention provides a method of determining the lifetime of a semiconductor device due to time dependent dielectric breakdown (TDDB). This method includes providing a plurality of samples of dielectric layer disposed as a gate dielectric layer of a MOS transistor, approximating a source / drain current density distribution as a first function of voltage applied on the samples, approximating a substrate current density distribution as a second function of voltage applied on the samples, approximating a dielectric layer lifetime distribution as a third function of source / drain current density and substrate current density in the samples, deriving, from the first, second, and the third functions, an empirical model wherein a dielectric layer lifetime is a function of voltage applied thereon, and using the model to determine dielectric layer lifetime at a pre-determined operating gate voltage.

The invention discloses a method and device for a joint test of electric arc current density distribution and electric arc pressure distribution, which are specifically applied to non-melt pole welding and belong to the technical field of electric arc tests. The device comprises a welding gun travelling mechanism, a cooling loop, an electric arc force testing system, a current testing system and the like. In the electric arc moving process, electric arc current flowing through a tested anode and electric arc force stressed on the tested anode are synchronously collected, an annular segmentation processing method is adopted for a circular section of an electric arc, the electric arc current density and the electric arc pressure are subjected to distributed computation, and an electric arc current density distribution curve and an electric arc pressure distribution curve are made. The device has the advantages of simple structure, simple testing steps and higher precision and credibility, and is convenient in data processing and solving.

The invention mainly discloses a heteromorphic high-rate polymer lithium ion battery piece, which comprises a fully heteromorphic positive film, a fully heteromorphic negative film and a ceramic diaphragm. The heterotype is a quadrangle, and one edge is an arc; two adjacent edges of the arc are parallel with each other; a fourth edge is vertical to the two parallel edges; and ears of an anode anda cathode are positioned on the fourth edge. At least one battery piece is subjected to heat sealing by an aluminum plastic packaging film which is compounded by multiple layers of composite materials to form batteries; and the batteries are overlapped and assembled in a series-parallel connection mode to form a battery pack. An effective implementation space of the batteries which are prepared from the heteromorphic battery piece is used fully in a cylindrical battery carrier cavity; and the current density in the battery piece is uniform, and the arc edge of the heteromorphic battery pack is consistent with a curve of the carrier to realize the contact of heat conduction surfaces, so that the heat dissipation efficiency is effectively improved when a large current is discharged.

A phase change memory cell and methods of fabricating the same are presented. The memory cell includes a variable resistance region and a top and bottom electrode. The shapes of the variable resistance region and the top electrode are configured to evenly distribute a current with a generally hemispherical current density distribution around the first electrode.

System for visualizing conductivity and current density distributions including a plurality of current injecting devices (100) for injecting currents into a measuring object; a measuring unit (200) for measuring a magnetic flux density due to the currents injected into a measuring object; an operating unit (300) for selecting one pair of the current injecting devices in succession so as to inject currents of different directions into the measuring object, and calculating directional components of an anisotropic conductivity inside of the measuring object on the basis of the measured magnetic flux density; and displaying means for visualizing an inside of the measuring object by using the calculated directional components of the anisotropic conductivity.

Ion sources and methods for generating an ion beam with a controllable ion current density distribution. The ion source includes a discharge chamber and an electromagnet adapted to generate a magnetic field for changing a density distribution of the plasma inside the discharge chamber and, thereby, to change the ion current density distribution.

The invention discloses a method and a system for preparing ultrathin metal lithium films through magnetron sputtering. The method includes at least putting base materials and metal lithium targets into a vacuum environment, and depositing the ultrathin metal lithium films on the base materials according to a direct-current magnetron sputtering method. The system comprises a direct-current magnetron sputtering device, at least one unwinding mechanism, at least one winding mechanism and at least one main roller. The unwinding mechanisms and the winding mechanisms are matched with each other, and are arranged in a first vacuum chamber, and the main rollers are arranged in a second vacuum chamber. The method and the system have the advantages that the metal lithium films deposited by the magnetron sputtering technology are thinner and have uniform and smooth surfaces and high adhesion to the base materials; when the metal lithium films serve as negative electrode materials of lithium secondary batteries, the surface current density distribution can be uniform, formation of lithium dendrites can be reduced, the electrochemical performance of the batteries can be improved, and the cyclelife of the batteries can be prolonged.

The present invention is a flow channel on an interconnect of a planar solid oxide fuel cell, comprising a first flow area and a second flow area where operation flows of a fuel cell flow evenly and smoothly to the interconnect to uniform the current density distribution of an electricity generation substrate, while the temperature differential in the fuel cell is lowered; the reliability of operation is improved; the performance of the fuel is elevated; and the usage period of the fuel cell is prolonged.

System for visualizing conductivity and current density distributions including a plurality of current injecting devices for injecting currents into a measuring object, an MRI scanner for measuring one directional component of a magnetic flux density due to each of the currents injected into a measuring object, an operating part for controlling the current injecting devices so as to inject currents of different directions into the measuring object, and calculating a conductivity distribution and a current density distribution inside of the measuring object by using the one directional component of a magnetic flux density, and displaying means for visualizing the conductivity and current density distributions calculated by the operating part, thereby permitting to visualize the conductivity and the current density of the measuring object more accurately.

In one embodiment, a sub-pad assembly of metal structures is located directly underneath a metal pad. The sub-pad assembly includes an upper level metal line structure abutting the metal pad, a lower level metal line structure located underneath the upper level metal line structure, and a set of metal vias that provide electrical connection between the lower level metal line structure located underneath the upper level metal line structure. In another embodiment, the reliability of a C4 ball is enhanced by employing a metal pad structure having a set of integrated metal vias that are segmented and distributed to facilitate uniform current density distribution within the C4 ball. The areal density of the cross-sectional area in the plurality of metal vias is higher at the center portion of the metal pad than at the peripheral portion of the planar portion of the metal pad.

The invention discloses a partition test system of the cold start current density and temperature of a fuel cell. A fuel cell system comprises a fuel cell, a thermocouple, an ice bath, an air intake system module, a high and low temperature alternating box, a cooling tube, a data acquisition module, a data processing module, and a load. The test method comprises the steps that: a current density test board is placed at an anode; both the cathode flow field plate and the cathode end plate have jacks, and the thermocouple is placed in the jack; the ice bath provides cold junction compensation for the thermocouple; the temperature in the high and low temperature alternating box is set to be the ambient temperature of the cold start; the intake system module supplies the fuel cell with oxidantand fuel and is connected to the load to make it work normally; the data acquisition module collects the voltage of the sampling resistor and the thermoelectric potential of the thermocouple. The data processing module converts the collected signal into a current density distribution map and a temperature distribution map at each moment of the fuel cell. Compared with the prior art, the inventionhas the advantages of low manufacturing cost, accurate measurement, simple structure and the like.

An MRI RF coil that is optimized for SENSE imaging is used in a method where the surface current density distribution on a coil former was calculated to maximize the SNRsense within a volume of interest. An analytic relationship was formulated between the SNRsense and surface current density on the coil former. The SNR at pixel ρ in a SENSE-MR image, SNRsense,ρ, is inversely proportional to the g-factor. The g-factor was formulated in terms of the B1 distribution of the coils. By specifying the geometry of the desired coil former and using a finite element mesh, the surface current distribution was calculated to maximize the SNRsense, by minimizing (1 / SNRsense) in the volume of interest using a least squares procedure. A simple two-coil array was tested and phantom images were collected. The results show that the new coil design method yielded better uniformity and SNR compared to standard coils.