69 results about "Resonance analysis" patented technology

The present invention provides a method for monitoring a condition of an electrical cable, the method comprising providing a reference signal CH0 and a signal CH1, said signal CH1 being the reference signal CH0 after amplitude and phase modulation by a cable impedance ZDUT of the electrical cable; calculating the cable impedance ZDUT as a function of the applied signal frequency based on the reference signal CH0 and the signal CH1; and analyzing said cable impedance providing an assessment of the cable condition. A system performing the method is also disclosed.

The invention discloses a multi-fan grid-connected resonance analysis method. The method comprises the following steps: on the basis of an output impedance model of an inverter, establishing a grid-connected equivalent model of a wind power plant; establishing a cable equivalent model according to the cable distribution characteristic under a harmonic state, and establishing the equivalent impedance of fan output power at a PCC (Point of Common Coupling) according to a relationship between the absorption power of the PCC and the fan output power to obtain the total impedance of a distributed wind power grid-connected system. The multi-fan grid-connected resonance analysis method has the advantages that the total impedance is calculated by establishing a distributed wind power grid-connected system model recorded with the cable and fan output power; the system model more accords with practical situations and has an application value and a practical significance for the resonance problem in an accurate analysis system.

The present invention provides a method for monitoring a condition of an electrical cable, the method including: providing a reference signal CH0 and a signal CH1, the signal CH1 being the reference signal CH0 after amplitude and phase modulation by a cable impedance ZDUT of the electrical cable; calculating the cable impedance ZDUT as a function of the applied signal frequency based on the reference signal CH0 and the signal CH1; and analyzing the cable impedance providing an assessment of the cable condition. A system performing the method is also disclosed.

A network text analysis called center resonance analysis (CRA) is presented which represents texts (or transcribed conversations) as networks of centering words. The networks of centering words are components of utterances or (specifically noun phrases) that authors and / or speakers deploy in a manner that makes their utterances coherent. A CRA network can be derived for any text, and abstractly represents its main concepts, their influence, and their interrelationships.

A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

A method of evaluating a vehicle warm-up working condition NVH performance relates to the vehicle development performance matching field, and comprises the rotating speed fluctuation analysis, the vehicle body resonance analysis, the warm-up state analysis and the rotating speed noise component analysis. The rotating speed fluctuation analysis is to acquire a rotating speed signal of an engine anddetermine whether the rotating speed fluctuation of the engine is less than 40 rpm and whether the rotating speed fluctuation of the engine has the regularity, the vehicle body resonance analysis isto determine that the noise obviously rises to an engine rotating speed section corresponding to the noise peak, namely a vehicle body resonance rotating speed section, according to a rotating speed-noise sweep frequency diagram, the warm-up state analysis is to check whether the warm-up rotating speed is overlapped with the vehicle body resonance rotating speed section, and the rotating speed noise component analysis is to analyze a noise energy spectrum and further check a noise source. The present invention mainly provides the evaluation method for solving the idling warm-up working condition noise from the aspects of structure and locomotive matching, the method is suitable for both the development of new vehicle type and the later noise optimization, can effectively improve the problem of louder noise on the warm-up working condition, and enables the client satisfaction degree to be improved.

The invention provides a node admittance matrix eigenvalue analysis method applied to a grid-connected-inverter-included parallel resonance situation, which belongs to the field of inverter-included grid-connected resonance analysis and detection and solves a problem that the resonance generation and the resonance generation frequency can be obtained when the existing resonance detection method analyzes resonance waves, but an optimal observation position and an optimal excitation position in a resonance generation process cannot be determined. When a parallel resonance situation is analyzed in a grid-connected-inverter-included system, the system is subjected to equivalence, a branch of a three-bus system for analyzing the resonance situation of a traditional electric power system is changed into an inverter to perform analysis, thereby obtaining a node admittance matrix of the system, wherein a matrix eigenvalue and left and right eigenvectors are calculated; by analyzing the eigenvalue under every frequency, the eigenvalue under a certain frequency occurs a maximum value, so that the resonance occurs under the frequency; by analyzing left and right eigenmatrixes, the optimal observation position and an optimal excitation position are obtained. The node admittance matrix eigenvalue analysis method provided by the invention is applied to a grid-connected-inverter-included power distribution system.

A superconducting RF coil array which may be used in whole body MRI scanners and / or in dedicated MRI systems. Some embodiments provide a superconducting RF coil array for at least one of receiving signals from and transmitting signals to a sample during magnetic resonance analysis of the sample, the superconducting RF coil array comprising a thermally conductive member configured to be cryogenically cooled, and a plurality of coils elements comprising superconducting material, wherein each coil element is thermally coupled to the thermally conductive member and is configured for at least one of (i) receiving a magnetic resonance signal from a spatial region that is contiguous with and / or overlaps a spatial region from which at least one other of the plurality of coil elements is configured to receive a signal and (ii) transmitting a radiofrequency signal to a spatial region that is contiguous with and / or overlaps a spatial region to which at least one other of the plurality coil elements is configured to transmit a radiofrequency signal.

The present invention discloses a single-core power cable resonance analysis method based on finite element simulation and an equivalent circuit. The method comprises: using finite element simulation to accurately calculate resistance of per unit length of a core wire of a single-core power cable, inductance of per unit length of the core wire of the single-core power cable, resistance of per unit length of a metal protective layer of the single-core power cable, inductance of per unit length of the metal protective layer of the single-core power cable, and capacitance of per unit length of the core wire to the metal protective layer; and using circuit simulation to simulate and analyze resonant circumstances of the core wire and the metal protective layer of the single-core power cable as well as a ground system under different grounding modes. The method is used in the field of power single-core power cable resonance analysis; and an analysis object is determined, analysis steps are simplified, and required resonant circumstances of any failure point can be provided, so that the method has relatively large reference value and significance for diagnosing and predicting a single-core power cable resonance failure.

The invention relates to a construction method for a differential expression profile model of hepatitis B virus (HBV) infectivity and alcoholic cirrhosis. According to the method, peripheral blood samples of liver cirrhosis patients with HBV infections, alcoholic cirrhosis patients and healthy people are sampled to carry out nulcear magnetic resonance analysis, then a multi-variable statistical analysis is adopted for the resulting spectrograms from the nulcear magnetic resonance analysis to obtain the differential expression profile model of the HBV infectivity and the alcoholic cirrhosis. According to the present invention, the metabonomics analysis method is adopted for analyzing the metabolic products of the liver cirrhosis patients with HBV infections, the alcoholic cirrhosis patients and the healthy people, such that the specific metabolic products related to the pathologic mechanisms of the liver cirrhosis with the HBV infection and the alcoholic cirrhosis are found, the differential expression profile model of the HBV infectivity and the alcoholic cirrhosis is constructed; such that a support is provided for specific diagnosis and treatment of the liver cirrhosis with the HBV infection and the alcoholic cirrhosis. In addition, the invention further relates to a differential expression profile model of the HBV infectivity and the alcoholic cirrhosis.

Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54°44′ relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

The invention relates to an earplug-type moving coil and moving iron mixed earphone. The earplug-type moving coil and moving iron mixed earphone is characterized in that a moving iron unit is installed in a moving coil cavity of a moving coil unit, a frequency divider provides signals for the moving coil unit and the moving iron unit, the moving coil unit is in charge of low and medium frequency sound production, the moving iron unit is in charge of high frequency sound production, and therefore the earphone increases the thickness and analysis of medium frequency, singing of people is richer in feeling and vitality, resonance analysis and raising of high frequency are improved, extremely-high frequency sound can be heard, hearing of people is more abundant, an HIFI high-quality music effect is achieved better, and listeners can experience enjoyment like live HIFI high-quality music better.

The invention discloses a capacitor resonance early warning system and method based on a capacitor branch monitoring point. The capacitor resonance early warning system is composed of a harmonic monitoring module, a data storage module, a resonance analysis starting module, a resonance point calculating module and a resonance early warning module which are connected in sequence. The harmonic monitoring module is used for continuously collecting the harmonic current data of all capacitor branch current transformers (CT). The data storage module is used for achieving storage of a power quality data collecting module and equipment machine account data. The resonance analysis starting module is used for starting the resonance point calculating module through a harmonic amplitude. The resonance point calculating module is used for estimating resonance points of a capacitor bank. The resonance early warning module is used for comprehensively estimating the resonance early warning level through integrated harmonic amplification times and the scanning result of harmonic impendence. The capacitor resonance early warning system and method based on the capacitor branch monitoring point have the advantages of being small in data collecting amount, simple in structure, and reliable in early warning result.

A method of designing a magnetic structure for providing a monotonic static magnetic field for magnetic resonance analysis. The method comprises: selecting a first geometry defining a volume-of-interest and selecting a magnetic field query, which is defined on a plurality of coordinates within the first geometry, the magnetic field query being monotonic. The method further comprises selecting a second geometry defining the magnetic structure and calculating a remanence distribution within the second geometry, by using the first geometry, the second geometry and the magnetic field query.

The invention discloses a permanent magnet device for magnetic resonance analysis. The permanent magnet device comprises a yoke, magnet pole plates, guide iron and shimming coil plates; one pair of symmetrical magnet pole plates are fixed to the yoke; the yoke encloses a closed magnet loop, and the magnet pole plates are located in the magnet loop; the shimming coil plates are fixed on the magnet pole plates through the guide iron; heating resistors are fixed onto the yoke; the heating resistors are connected with a constant temperature control power source; and the magnet pole plates are provided with temperature sensors; the permanent magnet device further comprises a PID constant temperature control system for regulating the current of the heating resistors to control the uniformity of a magnetic field; the temperature sensors are connected with the PID constant temperature control system; the shimming coil plates, a shimming power source group and an automatic shimming adjustment system are connected with the PID constant temperature control system; and the PID constant temperature control system adjusts the operating current of the heating resistors according to the compensation current of the shimming coil plates. With the permanent magnet device for magnetic resonance analysis provided by the invention adopted, the problem of deterioration of the stability of the magnetic field caused by magnet temperature variation which is further caused by heat emission increase of coils can be solved.

Embodiments relate to tire characterization systems and methods for combining direct tire pressure monitoring systems (TPMS) and tire resonance analysis in indirect tire pressure monitoring systems (TPMS) for the extraction of tire characteristics to characterize other tire parameters. In embodiments, iTPMS and methods that utilize anti-lock braking system (ABS) sensed signals coupled to an electronic control unit (ECU) that may comprise circuitry and / or controllers to process the sensed signals using a resonance frequency analysis (RFA) technique can be combined with direct tire pressure sensor measurements from direct TPMS systems. Because direct TPMS systems deliver a precise value of a tire characteristic (for example, tire pressure), one of the unknown parameters that influence the resonance effects can be removed. As a results, the detected resonance can be used to characterize another tire parameter that would not be accessible without knowledge of the precise value of the tire characteristic delivered by the direct TPMS system.

A device for ex situ magnetic resonance analysis is disclosed. The device comprises a static magnetic field unit (12) for generating a generally cylindrically symmetric static magnetic field outside the static magnetic field unit, and a radiofrequency unit (14) for generating a generally cylindrically symmetric radiofrequency field outside the radiofrequency unit. The radiofrequency field is perpendicular to the static magnetic field. A spatial inhomogeneity of the magnetic field substantially matches a spatial inhomogeneity of the radiofrequency field.

A device for ex situ magnetic resonance analysis is disclosed. The device comprises a static magnetic field unit (12) for generating a generally cylindrically symmetric static magnetic field outside the static magnetic field unit, and a radiofrequency unit (14) for generating a generally cylindrically symmetric radiofrequency field outside the radiofrequency unit. The radiofrequency field is perpendicular to the static magnetic field. A spatial inhomogeneity of the magnetic field substantially matches a spatial inhomogeneity of the radiofrequency field.

The invention relates to a carrier-based helicopter ship surface resonance modeling method, and belongs to the technical field of helicopter theoretical modeling. The method includes the steps that a single undercarriage load balance analysis model and a motion analysis model of a helicopter body on the ship surface are built; when a ship is guided to be brought down, modeling analysis is conducted on a bring-down device, the kinetic characteristic of the bring-down device is analyzed, and a sub system model is provided for overall ship surface resonance modeling analysis; according to the Newton's law of motion or the d'alembert's principle, a helicopter ship surface resonance analysis model for describing the ship surface motion and ship motion influences of a whole helicopter is built. According to the method, the built carrier-based helicopter ship surface resonance model can be applied to carrier-based helicopter ship surface resonance simulation analysis, and effective measures can be provided on the aspect of design to avoid and eliminate ship surface resonance.

The invention relates to a passive power filter structure, which is composed of a power supply, a balance reactor, a capacitor, a reactor and a load. A filter branch of a specific harmonic order is formed by resonance analysis and calculation of the inductance value of a specific reactor and the capacitance value of a corresponding capacitor. The order of high harmonic can be checked out by harmonic detection. A variety of specific harmonic filter branches are connected in parallel to form a filter circuit group, which can filter multiple harmonics. The problem of multiple harmonics generatedby a nonlinear load is solved. The roles of the balance reactor are to reduce the difficulty of tuning and compensate for voltage drop. The structure has the characteristics of high safety, long service life and convenient operation. The balance reactor also plays a role in power compensation.

A sample holder for use with magic angle spinning NMR and similar magnetic resonance analysis techniques which includes a sample holder sealed by an O-ring and a contact seal. The O-ring seals the sample volume during pressurization whereas the contact seal is active during analysis. The O-ring and the contact seal are disposed so that rotation of a plug selective engages one or both of the seals.

The invention relates to a method for cable condition monitoring of an electric cable. The method comprises inducing a test current in the electric cable, measuring a resulting current in a measurement point of the electric cable by measuring a magnetic nearfield of the electric cable, measuring a resulting voltage in the measurement point of the electric cable by measuring an electric nearfield of the cable, calculating an impedance of the electric cable based on the resulting current and the resulting voltage by a line resonance analysis system, and analysing the impedance by the line resonance analysis system establishing a condition of the electric cable. A coupler arrangement providing a non-galvanic connection to the cable is also disclosed.

A method of magnetic resonance analysis of a body having therein at least one molecular species and water is disclosed. The method comprises, subtracting magnetic resonance signals induced by a second radiofrequency pulse sequence from magnetic resonance signals induced by a first radiofrequency pulse sequence followed by a evolution period. The first radiofrequency pulse sequence is selected so as to suppress magnetization for the water while preserving a generally longitudinal magnetization to the at least one molecular species. The second radiofrequency pulse sequence being selected so as to suppress transverse and longitudinal magnetization for both the water and the at least one molecular species.

A magnetic resonance method is disclosed. The method comprises applying to the sample a plurality of pairs of bipolar gradient pulse subsequences, acquiring a magnetic resonance signal from the sample, analyzing the signal, and issuing a report regarding the analysis.

The invention discloses a grid-connected resonance analysis method and system based on a photovoltaic virtual synchronous generator. An information module is used for establishing a photovoltaic virtual synchronous generator grid-connected small signal model; the analysis module analyzes the grid-connected resonance mechanism of the photovoltaic virtual synchronous generator by using a state spacestrategy in combination with the small signal model, and constructs a state space matrix; the calculation module is used for solving characteristic values and left and right characteristic vectors ofthe state space matrix, obtaining resonance participation factors of all nodes when grid-connected resonance of the photovoltaic virtual synchronous generator occurs, and respectively carrying out calculation processing; and the analysis module analyzes the influence of element parameters on resonance stability by using a Lyapunov analysis strategy and a resonance participation factor to obtain aresonance influence rule. According to the method, the influence of the grid-connected resonance mechanism, accurate parameters and elements of the photovoltaic virtual synchronous generator on the stability is analyzed through a state space strategy, and a theoretical basis is provided for parameter design and optimization of the photovoltaic virtual synchronous generator in actual engineering and evaluation of the photovoltaic grid-connected electric energy quality.

The invention relates to the technical field of fault positioning, and discloses a cable water branch fault positioning method based on an impedance spectroscopy technology. The method comprises the steps of deriving a cable distribution parameter frequency change effect broadband impedance calculation model based on a transmission line theory; calculating cable line impedance by using the broadband impedance calculation model, and forming a cable broadband impedance spectrum; utilizing an algorithm to optimize a difference value function of an impedance spectrum calculation value and a measurement value to obtain defect section characteristic parameters; utilizing a linear resonance analysis method to analyze the defect section characteristic parameters so as to determine characteristic information of a defect section cable; analyzing the characteristic information of the defect section cable to diagnose the running state of the cable, detecting the change condition of the running state of the cable, and determining the water branch fault position of the cable. Compared with the prior art, the impedance calculation model is deduced through the transmission line theory, local defect characteristic parameters are extracted from impedance spectrum data, and accurate positioning and state evaluation of cable aging, damage and other defects are achieved.