130 results about "Transfer impedance" patented technology

An apparatus and method for measuring the transfer impedance of a structure. Oscillator driver 20 produces a small electrical drive signal into structure 40. Field probe 30 detects the electric field produced by the drive signal and is comprised of a skinny half-dipole and fat half-dipole antenna. Fat half-dipole 34 encloses synchronous detection circuitry. Power supplies are isolated for all components. Base station 10 communicates with oscillator driver 20 and field probe 30 via wireless links 92 and 44 to control the drive signal, the synchronous detection, and to determine the transfer impedance.

A method and device for determining acoustical transfer impedance The method comprises generating an acoustical volume velocity Q in the listening position, measuring a response quantity p, such as sound or vibration, at a suspected source position resulting from the volume velocity Q, and determining the acoustical transfer impedance Z_t as the response quantity p divided by the acoustical volume velocity Q, Z_t=p/Q. According to the invention the acoustical volume velocity Q is generated using a simulator (10) simulating acoustic properties of at least a head of a human being, the simulator comprising a simulated human ear (14, 15) with an orifice in the simulated head and a sound source (30) for outputting the acoustical volume velocity Q through the orifice. The output volume velocity Q from the orifice of an ear is estimated from measurements with two microphones inside the corresponding ear canal.

The invention discloses a radio frequency current probe characteristic calibrating method based on electromagnetic compatibility analysis and application and belongs to the field of electromagnetic compatibility analysis and application and electromagnetic interference noise measurement. According to a frequency section needing to be measured, in the method, the transfer impedance of a current probe is tested in a time domain by utilizing a dual-trace oscilloscope and then tested in a frequency domain by utilizing a vector network analyzer and adopting a scattering parameter method; and finally, a measurement conversion coefficient of the current probe can be more accurately obtained. The method has simple operation and accurate test, enables a result of electromagnetic interference noisemeasured by the current probe to be more accurate, and provides a theoretical basis for conducting the electromagnetic interference noise.

The present invention provides a method for using transferred-impedance filtering in RF (radio frequency) receivers (e.g., inside of a mobile communication device), wherein said filtering can be done with MOS-switches transferring impedance of a regular RC or RCL circuit to RF frequency filtering inside an RFIC (radio frequency integrated circuit).

The invention discloses an electromagnetic shielding effect simulation method for an electronic device chassis with conductive rubber, which is mainly used for solving the problem that the conductive rubber can not be simulated during shielding effect simulation in the prior art. The steps are as follows: establishing a multi-field coupling theoretical model for shielding effect of the chassis; introducing a chassis solid model established by Pro/E (pro/engineer) into Ansys for calculating structural displacement; transforming structural grids to electromagnetic grids and introducing into Feko software; measuring the transfer impedance of the conductive rubber, calculating the electrical conductivity and determining other electrical parameters; introducing the solid model into IcePak, and calculating the temperature of all devices in the chassis; determining the magnitude of a driving source through a curve of a device radiation electric field along with the temperature change according to the temperature; setting the parameters of the conductive rubber and the magnitude of the driving source in the FEKO and calculating the electric field value of an observation point outside the chassis; and putting the electric field value into the multi-field coupling theoretical model and obtaining the shielding effect of the chassis. The electromagnetic shielding effect simulation method can simulate the electromagnetic shielding effect of the electronic device chassis with the conductive rubber, and be used for guiding the design of electromagnetic compatibility of the structure of the chassis.

The invention discloses a CoSx nanomaterial used as super capacitor electrode and preparation method of the CoSx nanomaterial. The nanomaterial is composed of two parts, namely a CoSx core of a nanowire structure and CoSx nanosheets distributed on the surface of the nanowire in a leaf form. The CoSx nanomaterial is prepared by use of a two-step hydrothermal synthesis method, and the method comprises the following steps: preparing a precursor Co(CO3)0.35Cl0.20(OH)1.10 nanowire by use of a hydrothermal reaction method, and then performing sulfidizing treatment on the precursor by use of a hydrothermal reaction method, thereby obtaining the CoSx nanomaterial. The nanomaterial is tested by use of a triple-electrode system, and the nano-electrode material shows high specific capacity of 2383F/g under the current density of 10A/g and still has the specific capacity of 1488F/g after 1000 charge-discharge cycles, and the charge transfer impedance of the nano-electrode material is 1.11omega/cm<2>. The CoSx nano-electrode material prepared by use of the method has the advantages of high specific capacity, good cycle performance, simple preparation method and low cost.

The invention discloses a nitrogen and phosphor-doped biomass carbon material synthetic method and an application of the biomass carbon material in a microbiological fuel cell cathode. The method comprises the following steps: taking cellular biomass as a substrate, after pretreatment, respectively sintering the cellular biomass to a carbon material under inert atmosphere at the temperatures of 600 DEG C, 700 DEG C and 800 DEG C, taking cellular as a carbon source, respectively taking melamine and 1,2-vinyl diphosphate as a nitrogen source and a phosphorus source, mixing the raw materials according to a certain proportion for doping, performing a hydrothermal reaction for 5 h in a reaction vessel at the temperature of 100 DEG C, and successfully preparing a nitrogen and phosphor-doped carbon N/P-C semispherical porous microbe cathode material. The method has the advantages that the microbe cathode oxygen reduction catalytic activity is increased, the biomass carbon material has more excellent cycle stability, catalysis electrode charge transfer impedance is reduced, the electron transfer rate is accelerated, a cathode oxygen reduction reaction is promoted, and the provided electric energy can supplies the requirements of other fields.

The invention discloses a molybdenum carbide material and a molybdenum carbide@molybdenum sulfide composite material, and preparation methods and applications thereof. The preparation method of the molybdenum carbide material comprises the following steps: adding a carbon source and a molybdenum source to a dispersion liquid, performing stirring for 6-12 h, drying the obtained mixture at 80-120 DEG C, grinding the dried mixture, and collecting the ground mixture to form a molybdenum carbide precursor; and performing temperature programming on the molybdenum carbide precursor to 400-900 DEG C from room temperature in an inert atmosphere, calcining the precursor at 400-900 DEG C for 1-3 h, grinding the calcined precursor, and collecting the ground calcined precursor to obtain molybdenum carbide. The molybdenum carbide is vulcanized at 160-400 DEG C by using a vulcanizing agent to obtain molybdenum carbide@molybdenum sulfide. The molybdenum carbide and the molybdenum carbide@molybdenum sulfide respectively have the morphology of a porous nanosheet structure, and the microstructure facilitates storage of an electrolyte and reduction of the charge transfer impedance and provides a lot of electrocatalytic activity sites; and the material and the composite material can be used as an HER electrocatalyst, have a high catalytic activity and a good stability, and are expected to replace aPt-based catalyst for electrolysis of water to produce hydrogen.

The invention discloses a method for testing radiated noises of a digital gravity metering device, which comprises the following steps of: calculating corresponding transfer impedance according to a high-frequency current clamp structure; putting a measuring loop in the high-frequency current clamp on a power cord of the digital gravity metering device so as to extract a first noise voltage and a second noise voltage in the power cord; performing a vector operation and a vector difference operation on the first noise voltage and the second noise voltage by using a noise separation network so as to obtain a difference mode conducted noise voltage and a common mode conducted noise voltage; performing operation on the difference mode conducted noise voltage, the common mode conducted noise voltage and the transfer impedance of the high-frequency current clamp to obtain a difference mode conducted noise current and a common mode conducted noise current; and acquiring an electric field which emits the radiation noises in a free space according to a common mode noise current formula. In the method, the common mode noise current of a single-chip digital gravity metering device is measured by using the high-frequency current clamp and the noise separation network, and the radiated noises are predicted through the common mode noise current.

The invention relates to a W-doped and modified high-nickel ternary positive electrode material, and belongs to the field of a chemical energy storage battery. The material is obtained by grinding anduniformly mixing a mixture of a nickel-cobalt manganese hydroxide, a tungsten source and LiOH.H2O to obtain solid powder, calcining the solid powder under an oxygen atmosphere and then cooling. By Wdoping, the material structure can be stabilized, charger transfer impedance is reduced, so that the electrochemical performance of the material is improved, and the material capacity retention rate and the rate performance of the material are improved. The synthesis method is simple, the process and the technology are easy to implement, and large-scale commercial application can be achieved.

The invention relates to a hybrid mesh partition method in the field of electronic technologies, in particular to the hybrid mesh partition method with the design of integrity of a system-level packaging power supply. The hybrid mesh partition method comprises the following steps: (1) decomposing an irregular power supply/ground plane into a series of convex polygons by utilizing convex partition treatment; (2) obtaining an optimal rectangular mesh based on the recursive partitioning technology of the rectangular mesh, setting auxiliary ports on sides of the rectangular mesh, and establishing the transfer impedance relationship among the ports; (3) adopting a triangular mesh to fill the remaining structure, and carrying out modeling of an equivalent circuit for the triangular mesh; (4) establishing the electrical relationship among the ports at an interface of the rectangular mesh and the triangular mesh; and (5) solving simultaneous overall equations. The hybrid mesh partition method has the advantages of a wide range of applications, few internal nodes, high analysis precision and efficiency and the like.

The invention discloses a capacitance type voltage transformer harmonic voltage measurement method and device. The method comprises the following steps that: establishing the equivalent circuit modelof a capacitance type voltage transformer; according to the equivalent circuit model, establishing a relational expression between the transfer impedance of the capacitance type voltage transformer and primary side current and a relational expression between the transfer impedance of the capacitance type voltage transformer and secondary side voltage; establishing a ternary nonlinear equation setcontaining the primary side current, the secondary side voltage and stray capacitance in the equivalent circuit model; and solving the ternary nonlinear equation set, according to the solved value ofthe stray capacitance, calculating the equivalent impendence of the capacitance type voltage transformer, and according to a primary side harmonic current signal which is actually measured when the capacitance type voltage transformer operates, calculating a primary side harmonic voltage signal. By use of the method, the technical problems in an existing capacitance type voltage transformer harmonic voltage measurement method that a structure is complex, cost is high, reliability is difficult in prediction and the method is not suitable for field measurement since the capacitance type voltagetransformer needs to be transformed or depends on a high-voltage harmonic source can be solved.

The invention relates to a calculation method of direct-current components of short circuit current of a power supply system. A key problem of calculation of direct current components of short circuit current is researched; a frequency domain equivalent theory of the direct-current component calculation is provided; based on the principle, the method for calculating direct current of the short circuit current and attenuation features by use of a transfer impedance is provided. In the method, effects on short circuit current and direct current component calculation imposed by frequency are considered, and features of mathematical models of a complex electric power system network are combined, so the calculation results are quire precise, and the method is simple to operate, and usable for routine calculation of engineering.

The invention discloses a method and a system for evaluating consistency of lithium ion batteries, and belongs to the technical field of detection of power batteries. The method comprises the following steps of performing forming and capacity grading treatment on a plurality of lithium ion batteries with same nominal capacity, so as to obtain the primarily graded lithium ion batteries; performingalternating current impedance spectrum testing on the primarily graded lithium ion batteries at low temperature, so as to obtain the charge transfer impedance of the primarily graded lithium ion batteries; according to the size of the charge transfer impedance, evaluating the consistency of the primarily graded lithium ion batteries. The method has the advantages that by additionally performing the alternating current impedance testing on the batteries at low temperature, the problem of better consistency of electric properties of the batteries at normal temperature but poorer consistency at low temperature is relieved, the batteries are reasonably grouped, and the excellent properties of the battery groups during charging and discharging at low temperature and normal temperature are guaranteed.

A layout design of a multilayer printed circuit board (PCB) is provided, which makes use of partial electromagnetic band gap (EBG) structure to constitute a power layer or a ground layer. The EBG structure is mainly used on the linear transmission path from the port of the first integrated circuit to the port of the second integrated circuit on the power layer or the ground layer, so as to overcome the problems concerning self-impedance and transfer-impedance easily occurred in the conventional complete EBG structure.

The invention discloses a modified nickel oxide negative material. Nickel oxide with a hollow structure is taken as a matrix and is doped with metal elements (including one or more of lithium, sodium and potassium). A preparation method of the modified nickel oxide negative material comprises the following steps: dissolving metal element nitrate and nickel nitrate in water for mixing uniformly to obtain a mixed liquor, and then performing spray pyrolysis treatment on the obtained mixed liquor, thereby obtaining the modified nickel oxide negative material, wherein a metal element is one or more of lithium, sodium and potassium, and the molar concentration ratio of metal ions and nickel ions in the mixed liquor is equal to (1:100)-(10:100). The nickel oxide negative material has a hollow spherical feature, so that diffusion paths of lithium ions are reduced, and the volume change in a circulating process is alleviated to a certain degree. As nickel oxide is doped with the metal elements including lithium, sodium and potassium, the conductivity of the material is improved, the charge transfer impedance is lowered, and the electrochemical performance of a battery is improved.

The invention discloses an operational curved surface method for determining asymmetric short-circuit current of a distributed generation access power grid. The method comprises steps of acquiring a three-node simplified network and transfer impedance between different nodes by using network simplification when multiple DGs and conventional generators have access to the power grid; in view of different types of asymmetric short-circuit faults, ignoring the influence of DG zero-sequence current injection, obtaining a short-circuit calculation compound sequence network and positive and negative sequence augmented networks according to a fault point boundary condition, and calculating the additional voltage and additional impedance in the augmented networks; performing Thevenin equivalent on systems except the DG access points in the positive and negative sequence networks, and deriving short-circuit impedance and open-circuit voltage open-circuit voltage computational formulas when DC injection current is zero; establishing a operational curved surface of a DG short-circuit current negative-sequence component, computing impedance, and positive and negative sequence open-circuit voltage in order to obtain a DG short-circuit current negative-sequence component; calculating a DG asymmetric short-circuit current positive-sequence component in combination with a three-phase short-circuit operational curved surface according to a DG access positive-sequence augmented network access point equivalent open-circuit voltage computing method.

The invention belongs to the technical field of cathode materials, and specifically discloses a preparation method of a phosphate-coated metal-doped ternary cathode active material. A ternary cathodematerial uniformly coated with nanometer oxide is obtained through sintering after simple liquid phase ultrasonic treatment, the ternary cathode material is uniformly coated with the metal phosphate after high temperature treatment with a phosphoric acid source to obtain a metal ion-doped ternary cathode material. The ion surface diffusion and internal transfer impedance can be reduced through physical coating and cation doping, the side reaction between the electrolyte and the cathode material is reduced, and the layered structure of the material is stabilized, so that the cycle stability andthe rate performance of the ternary cathode material are greatly improved.

The invention discloses a preparation method of a shape-controllable ordered layer porous chromium carbide skeleton carbon material for a supercapacitor. In a preparation process, a chromium carbide precursor with a special shape is synthesized through template control, a chromium atom is removed by using an etching agent in situ to obtain a micropore, then orderly arranged meso pores with regular pore passages are obtained by removing a mesopore template to form porous carbon hierarchically combined by meso pore and micropores, wherein the shape of the chromium carbide framework carbon can be controlled through a template process, the relative content of the micropores and the meso pores can be adjusted through controlling a synthesis reaction condition and a raw material ratio, and thus the ordered layer porous chromium carbide skeleton carbon the pore structure and the pore diameter distribution of which are accurate and adjustable in atom-scale level and controllable in shape is obtained. According to the preparation method, a shape-controlled porous electrode material for a novel supercapacitor, which is high in specific capacitance, small in ion diffusion and transfer impedance, better in rate capability, excellent in cycle performance and controllable in shape can be obtained.

The invention discloses a method for recycling a retired battery, and relates to the technical field of recycling of lithium ion batteries. The method comprises the following steps of firstly, selecting single retired batteries with actual capacity which is 60-80% of the nominal capacity, and performing grading on the batteries based on battery capacity; next, according to the different grades, injecting the batteries with electrolytes of different weights and sealing the batteries; and finally, carrying out grading and grouping again according to the battery capacity and the charge transfer impedance after the batteries are activated. By adopting the method disclosed by the invention, the capacity of the batteries repaired by the method can be recovered to the level of an in-service powerbattery, and the recycling performance is high.

The invention discloses a Co0.85Se nanomaterial used as a supercapacitor electrode material, and a preparation method thereof. The nanometerial is a connected space hole-containing three-dimensional porous nanostructure formed through interlacing nanosheets. The Co0.85Se nanomaterial is synthesized through a one-step hydrothermal technology without using an organic template or a surfactant, so the method has the advantages of simple preparation, energy saving, and suitableness for industrial production. A Co0.85Se nanomaterial electrode containing the synthesized nanosheet structure is tested in a three-electrode system, a KOH solution is adopted as an electrolyte, the electrode nanomaterial has a high specific capacity of 1528F/g at a current density of 1A/g and still keeps 90% or above of the initial capacitance after 5000 frequency cycle charge and discharge at a high current of 10A/g, the internal resistance of the electrode nanomaterial is 1.4omega/cm<2>, and the charge transfer impedance is 0.73omega/cm<2>. The Co0.85Se electrode nanomaterial has the advantages of large specific surface area, high specific capacitance, good cycle performances, simple preparation cost and low cost.