111 results about "Surface impedance" patented technology

A surface impedance sensor and method are provided. The surface impedance sensor generally includes first and second electrodes, a driver circuit to drive the electrodes at a plurality of driving frequencies, and a detection circuit to measure the impedance across the first and second electrodes for comparison against a plurality of reference profiles. The method generally includes measuring the localized surface impedance for each of a plurality of driving frequencies to generate a measured profile, and correlating the measured profile with a reference profile. The system and method can verify contact with a particular surface and can be used with a variety of host devices, including for example ultrasound delivery devices.

The present invention generally relates to the field of microwave antennas, and, more particularly, to a number of three-dimensional designs for the radiation element of an ultra-wideband monopole antenna with a symmetrical omni-directional radiation pattern operated in the frequency range between 3.1 GHz and 10.6 GHz. Said antenna is connected to the analog front-end circuitry of a wireless communication device used for transmitting and/or receiving microwave signals and meets the FCC requirements in terms of antenna gain, radiation pattern, polarization, frequency bandwidth, group delay, and size. It comprises a radiation element consisting of an air- and/or dielectric-filled cavity structure with a base plane and a radiator plane. A metallic ground plane having a relatively high surface impedance to electromagnetic waves within said frequency range, which is printed on a dielectric substrate, serves as a reflector. The monopole antenna further comprises an antenna feeding circuitry used for electronically steering the symmetrical omni-directional radiation pattern and a feeding line connecting the antenna feeding circuitry with the base plane of the radiation element. Thereby, parts of the analog front-end circuitry can optionally be placed within the air-filled part of the radiation element of the antenna. The proposed designs include a radiation element having the form of a truncated right circular cone, rotational-symmetric radiation elements with a convexly- or concavely-shaped 3D surface, respectively, a radiation element in the form of a truncated right regular pyramid with a square base plane, and radiation elements with a combined structure comprising a conical, pyramidal, convexly- or concavely-shaped first part and a closed cylindrical or cuboidal second part whose top plane is arranged on top of the congruent base plane of said first part. Further embodiments include radiation elements with the form of a radially notched cylinder or hemisphere as well as combined structures consisting of at least two convexly-shaped elements or two conical parts, respectively, stacked on top of each other.

The invention provides a method for monitoring the regional evapotranspiration on the basis of remote sensing, comprising the following steps of: (1) obtaining the multi-temporal and multi-resolution satellite remote-sensing image data at a specific region; (2) carrying out remote sensing inversion to the key parameters on the ground surface; (3) calculating the impedance of each pixel during the exchanging process of the geogas energy by a remote-sensing geogas exchanging model, calculating the sensible heat flux used for heating the air above each pixel, calculating the latent heat energy by an energy remainder formula and inquiring into effective surface impedance; (4) establishing a surface impedance model in a daily dimension so as to obtain a daily ground surface impedance; and (5) working out the daily evapotranspiration by applying a P-M model repeatedly and carrying out time accumulation and dimension down-scaling, thus finally determining the regional ground surface evapotranspiration. According to the validation of the practical measurement at multi-regions, the method for monitoring the regional evapotranspiration is proved to be effective.

The invention discloses a transmission line, a leaky-wave antenna multiplexing device and a beam scanning method thereof. The device comprises a dielectric substrate, a metal strip and a metal floorboard positioned on the front and back surfaces of the dielectric substrate, and periodically alternatively arranged capacitors and variable capacitance diodes for connecting the metal floorboard and the metal strip via the through holes. The metal strip comprises gradient microstrip line structures at two ends and an artificial surface plasmon structure positioned therebetween. When the capacitance value of the variable capacitance diode is identical with that of the fixed capacitor, the surface impedance of the device is identical, and thus the function of the transmission line is achieved; when the capacitance value of the variable capacitance diode is not identical with that of the fixed capacitor, the surface impedance of the device is periodically modulated, and thus the radiation function of the leaky-wave antenna is achieved. Voltage is used as a regulation means, and fixed frequency beam scanning can be achieved along with the change of the voltage; the device is simple to manufacture, convenient to operate and prone to integrate; only a photoetching step is needed, so that cost is saved, and machining errors caused by a multi-layer structure are avoided.

The invention is a transparent conductive laminated body with visible adjustment layers. The transparent conductive laminated body comprises a transparent organic polymer substrate, a first visible adjustment layer and a second visible adjustment layer, a third visible adjustment layer and a transparent conductive layer which are sequentially stacked. The refractive index of the first visible adjustment layer is between 1.3 and 1.7, and the optical thickness of the first visible adjustment layer is between 10nm and 260nm; the refractive index of the second visible adjustment layer is between 1.8 and 2.5, and the optical thickness of the second visible adjustment layer is between 3nm and 150nm; the refractive index of the first visible adjustment layer is between 1.3 and 1.7, and the optical thickness of the first visible adjustment layer is between 10nm and 260nm; and the root mean square value of the difference between the reflectivity of the wavelength of the transparent conductive laminated body and the average reflectivity is less than 3% within the visible wavelength scope of 380nm-700nm, and the surface impedance is between 130 and 1000omega/cm<2>.

An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. The present invention provides increased effective tool surface impedance by increasing self-inductance of the paths in which induced eddy currents flow on the surface of the multi-component induction instruments. The tool enables downhole tool designers to build more effective and better-protected radial induction arrays for existing and future downhole instruments operating in the frequency and/or time domains. In this case the array measurement results contain information primarily about the formation's vertical resistivity. The tool makes it possible to combine radial arrays with coaxial arrays that conventionally measure horizontal formation resistivity. This combination enables obtaining a full resistivity tensor to evaluate formation resistivity anisotropy. The tool provides a composite non-conductive housing to reduce or even avoid the effects of parasitic eddy currents flowing on the tool surface. The tool provides a non-magnetic housing that is conductive which reduces the effects of conductive materials near coils and, primarily, the receiver. The tool provides a non-conductive coating is placed over the housing to prevent high frequency eddy currents from leaking from the housing in the conductive mud of the adjacent wellbore and returning to the housing.

The invention discloses a graphene-based coating agent. The graphene-based coating agent comprises, 0.1-1 part of nano-graphite, 1-3 parts of a graphene dispersing agent, 2-10 parts of fluorine-bearing acid, 2-10 parts of fluorine-bearing acid salt, 1-2 parts of a silane coupling agent, 2-5 parts of a complexing agent, 0-2 parts of a surface wetting agent and 70-95 parts of water. The graphene-based coating agent has the advantages of short film forming time, good film forming property and environment friendliness. An inorganic film formed on the surface of metal through the graphene-based coating agent has excellent lubricity and corrosion resistance and is thin. The formed inorganic nanofilm has excellent conductivity, lubricating property and corrosion resistance and has higher corrosion resistance and longer salt mist time, and therefore corrosion resistance of a metal substrate is better improved, surface impedance of the metal is not influenced after the film is formed, and finish machining of the metal is better facilitated.

In accordance with the present invention, an aircraft engine is provided with a component which helps reduce the noise generated by the engine. The component has a first aerodynamic surface, a second aerodynamic surface, and a system for reducing noise without altering a pressure differential between the first aerodynamic surface and the second aerodynamic surface.

The invention relates to a halogen-free polyolefin composition, which comprises: (a) 25-75wt% of polyolefin resin; (b) 15-65wt% of a halogen-free flame retardant; and (c) 5-10wt% of an antistatic agent. The flame retardant and the antistatic agent of the composition meet the MT113-1995 specified requirements, which include: (i) flame retardance: the flame combustion duration is less than 3S (after removal of an alcohol blast burner), the flameless combustion duration is less than 30s (after removal of the alcohol blast burner), and the flame propagation length is not more than 280mm; and (ii) antistatic property: the surface impedance is less than 10<8>Ohm. And the mechanical strength of the composition meets the requirements of: notched Charpy impact strength of greater than 20kJ/m<2>, tensile strength of greater than 20MPa, and an elastic modulus of greater than or equal to 1100MPa.

The invention provides a modified nickel cobalt manganese ternary composite electrode material coated on an oxide surface and a preparation method thereof. A coating layer of the composite electrode material is prepared from two or three metal oxides MxOy, wherein M is niobium, zirconium or yttrium; the thickness of the coating layer is 0.5-50nm and the weight percent in the composite electrode material is 1%-10%; the prepared nickel cobalt manganese composite electrode material has an alpha-NaFeO2 layered structure. Nickel acetate, cobalt acetate, manganese acetate and lithium acetate are taken as raw materials, the metal oxides are served as surface coating matters and the high-temperature sintering and in-situ coating combined technology is adopted for preparing the high-performance composite electrode material. The coating layer of the composite electrode material can prevent the metal ions in active materials from dissolving, can resist against the corrosion of HF to active materials and can reduce the surface impedance and promote the cycling stability. The preparation process is simple, the operation is easy, the production period is short, the equipment requirement is low and industrial development and popularization and application are benefited.

The invention discloses an anti-static release film and a manufacturing method thereof. The anti-static release film comprises three layers, wherein the first layer is a base material of which the main component is polyethylene glycol terephthalate (PET); the second layer is a conductive coating of which the main component is a conductive macromolecular compound with a polythiophene and polyaniline-containing co-orbit macromolecular structure; and the third layer is a release agent coating of which the main component is an addition organic silicon material. The manufacturing method comprises the following steps of: firstly, diluting and coating an anti-static coating; secondly, drying the coating; thirdly, testing surface impedance, and finally, coating a release coating and solidifying the coating to form a roll. The anti-static release film has the advantages of high release force and conductivity, and release and anti-static effects.

The invention discloses a method for controlling uplink power. When the uplink interference is normal, the uplink control is realized by the traditional uplink power control computation method; when the uplink interference has an overload trend and is not serious, if a measured SIR (Surface Impedance Resistance) is less than or equal to a target SIR, the transmitting power of UE (User Equipment) with a larger difference between the measured SIR and the target SIR is enhanced; the mode of alternately enhancing and reducing the transmitting power is adopted for the UE with a smaller difference between the measured SIR and the target SIR so that the competitive raise of the transmitting power of the UE is inhibited; and when the uplink interference is much serious, the mode of alternately enhancing and reducing the transmitting power is adopted for all UEs that follow the fact that the measured SIR is less than or equal to the target SIR so that the transmitting power of the UEs can be kept in a relatively constant state to avoid self-excitation of the power. The invention also provides a method for controlling downlink power. By applying the invention, the problem of the self-excitation of the power due to the competitive raise of the power of adjacent zones under the condition that the same frequency interference is much serious can be solved and the cutting off rate of a user is reduced.

The invention discloses a holographic modulation based artificial tensor impedance surfaced antenna and an implementation method thereof. The artificial tensor impedance surfaced antenna systematically comprises an artificial tensor impendance surface composed of multiple unit lattices equal in size; each unit lattice sequentially comprises a metal floor, a dielectric substrate and a metal paster from top to bottom; surface impedance corresponding to the unit lattices of the artificial tensor impedance surface is controlled through geometric parameters of the metal paster, so that the surface impedance on the surface of the antenna is distributed according to holographic interference pattern rules of a source field and a target field. The implementation method includes the steps of S1, scalar impedance extraction and simulation; 2), matching of equivalent scalar surface impedance curves; S3, holographic modulation of the sensor surface impedance; S4, antenna modeling and simulation. The target radiation field of a specific planning mode is obtained by the aid of the holographic tensor surface impedance principle, an equivalent scalar surface impedance matching criterion is put forward, and data volume needed in modulation of the tensor surface impedance is effectively reduced.

A reflection frequency conversion device using an active metamaterial surface comprising: a plate-shaped active metamaterial surface which is configured to continuously convert a phase of a reflected wave by changing surface impedance characteristics in accordance with input voltage; and an arbitrary waveform generator which provides a voltage waveform capable of linearly changing the phase of the reflected wave in accordance with time to the metamaterial surface, where a reflection frequency generated on the metamaterial surface is converted in accordance with a frequency of the voltage waveform provided from the arbitrary waveform generator, where a plurality of metamaterial unit structures are periodically disposed on the metamaterial surface, and where the metamaterial unit structure is a high impedance surface (HIS) provided with a variable capacitor, and the capacitance of the variable capacitor is changed in accordance with applied voltage to change the phase of the reflected wave.

The invention relates to a fluoride-modified nickel-enriched ternary composite electrode material. The fluoride-modified nickel-enriched ternary composite electrode material comprises a nickel-enriched ternary composite electrode material and a modifying layer, wherein the nickel-enriched ternary composite electrode material is prepared from the following raw materials: lithium carbonate, nickel carbonate, cobalt carbonate and manganese carbonate; the molar ratio of the lithium element, the nickel element, the cobalt element and the manganese element is (1.0-1.1):(0.6-0.8):(0.2-0.1):(0.2-0.1);the modifying layer is metal fluoride; the metal fluoride accounts for 1-5% of the mass percentage of the total electrode material. The invention further relates to a preparation method of the composite electrode material. After the nickel-enriched ternary electrode material is modified by the fluoride, dissolution of metal ions in an active material can be prevented, corrosion of the active material by an electrolyte can be resisted, the surface impedance can be reduced, the cycle stability of the material can be improved, and the problems of poor stability and fast capacity attenuation of the nickel-cobalt-manganese ternary electrode material can be solved.

The invention discloses a resonator apparatus and measurement method for measuring surface intrinsic impedance of a high-temperature superconductive film. The apparatus is divided into a cavity portion and a height adjusting portion. The cavity portion comprises a base plate, a copper cavity, a spring, a lower sample table, a medium column, an upper sample table, a coupling cable, a self-parallel ball and a phosphor copper pressure sheet, wherein the upper sample table can move up and down through the height adjusting portion. The height adjusting portion comprises a metal fixation plate, a metal rod, a metal pipe, piezoelectric ceramics and a spring, wherein the piezoelectric ceramics realizes height adjustment. The cavity portion and the height adjusting portion are connected through polyethylene rods and a polyethylene block. Measurement employs a TE012 mode and a TE021 mode, and the intrinsic surface impedance of the superconductive film is obtained through measurement of the resonant frequency and the quality factor of a medium resonant cavity. The apparatus provided by the invention is applied to high-temperature superconductive films with any thicknesses, can measure effective surface impedance of the high-temperature superconductive films and can also measure intrinsic impedance of the high-temperature superconductive films.

The device according to an exemplary embodiment of the present invention relates to an area of wireless communication and can be used for shielding from electromagnetic radiation. The electromagnetic screen with the big surface impedance contains a flat metal reflector substrate and two lattices of capacitor type that are shifted from each other on a share of the period in parallel and located above the reflector substrate. At least one of lateral edges of the lattices has an electric connection with an edge of the reflector substrate.

The invention discloses a low-loss magnetic insulation sheet preparation process and a magnetic insulation sheet. The low-loss magnetic insulation sheet preparation process disclosed by the inventionis reasonable and simple in structure, low in production cost and complete in function. The gaps with uniform and orderly shapes and a certain size are formed by contacting a graphic tube and the strip material through the surface treatment process, the powder surface insulation and surface phosphating process and surface oxidation method, so that the electromagnetic property magnetic conductivityof the magnetic insulation sheet is relatively average, the magnetic loss is small, the quality factor is high, the shapes are really uniform in size, the gap sizes are good in consistency, the colloid fallibility is excellent, the surface impedance is increased, and the eddy current loss is small; the eddy current loss is further reduced after adding the strip material surface treatment, so thatthe discharging efficiency is improved, the magnetic insulation sheet is good in stability, and the automation is easy to realize.

The invention discloses a method for coating nickel-cobalt lithium manganate. A nickel-cobalt lithium manganate material with high nickel content is coated by a nickel-cobalt lithium manganate material with low nickel content. The invention also discloses a nickel-cobalt lithium manganate prepared by the method. A nickel-cobalt lithium manganate surface is coated and modified, thus, relatively high initial capacity of nickel-cobalt lithium manganate is maintained, the cycle performance is greatly improved, the capacity attenuation of a battery after circulation for many times is obviously reduced under high temperature and high rate, side reaction between an electrolyte and an electrode material is reduced, dissolving of metal ions of Ni<2+>, Co<3+> and Mn<4+> is prevented, so that the impedance of the battery is reduced, and the electrochemical performance of the material is greatly improved; and meanwhile, the nickel-cobalt lithium manganate material is coated by a ternary material with low nickel, and the defects of high phase surface impedance, low Li<+> migration rate, poor power performance of the material and the like caused by coating of a conventional oxide are overcome.

The invention provides a conformal surface wave antenna based on a holographic metasurface. The conformal surface wave antenna comprises a monopole feed source and a holographic impedance surface, theholographic impedance surface comprises m*n periodically arranged impedance surface units, each impedance surface unit comprises a dielectric plate, a square metal patch printed at the center position of the upper surface of the dielectric plate and a metal floor arranged at the lower surface of the dielectric plate, the surface impedance of each impedance surface unit is distributed based on theinterference pattern of a holographic principle, the reference waves corresponding to the distribution of the interference patterns are cylindrical surface waves generated by the monopole feed source, and a target wave is a radiation plane wave in the endfire direction of the holographic impedance surface. Directed radiation is achieved in the endfire direction of the conformal surface wave antenna prior to generation of the cylindrical surface waves, which are subjected to impedance modulation of the holographic impedance surface, by employing the monopole feed source to form a flat plane wave, and when a conformal surface wave antenna meets a curved surface bulge, diffraction propagation of the surface wave can be achieved.