183 results about "Dielectric spectrum" patented technology

The invention discloses a testing device for an oiled paper compound insulation frequency domain dielectric spectrum and conductivity test. The testing device comprises a high temperature resistance organic glass tank, an upper stainless steel sealing cover plate, a lower stainless steel sealing cover plate, electrode systems, an electric heating blanket, a temperature sensor, a temperature display and control device and the like. The upper end and the lower end of the tank are sealed with the stainless steel sealing cover plates, the tank is filled with transformer oil, the temperature sensor is arranged at the bottom of the tank, the temperature sensor is connected with the temperature display and control device, an air valve and an air pressure gauge are arranged on the upper cover plate of the tank, an oil valve is arranged on the lower cover plate, the electrode systems are arranged at the bottom of the tank, an insulation paper board is arranged between the upper electrode system and the lower electrode system, an upper electrode is connected with a thread micrometer, a measuring electrode in a lower electrode is insulated from a grounding electrode through a polytetrafluoroethylene casing pipe, and the grounding electrode is connected with the lower cover plate. According to the testing device for the oiled paper compound insulation frequency domain dielectric spectrum and conductivity test, a vacuum oiling way is adopted for achieving sufficient immersion of the insulation paper board and insulating oil, a heating device is applied outside the tank to set different environment temperatures, and the oiled paper insulation frequency domain dielectric spectrum and conductivity are accurately tested.

The invention comprises: a photoinduction dielectrophoresis chip, machine vision unit, a vision servo unit and a virtual electrode writing unit. Said photoinduction dielectrophoresis chip is located on a supporting unit and is used for placing the simple cell suspension; said photoinduction dielectrophoresis chip is a three layer hamburger structure; said three layer structure comprises a conducting glass layer, a micro channel layer and a photoinduction chip; on the conducting glass, respectively setting an inlet and an outlet.

The invention relates to the biological identification technology field and especially relates to an identity identification apparatus and a method thereof. The identity identification apparatus comprises a biological characteristic signal acquisition module, a biological characteristic extraction module and a biological characteristic identification module. The biological characteristic signal acquisition module is used for collecting a fingerprint image and a finger portion group delay curve. The biological characteristic extraction module is used for extracting a fingerprint characteristic value and a group delay characteristic value respectively according to the fingerprint image and the finger portion group delay curve. The biological characteristic identification module is used for constructing an identity identification model through a training sample set and carrying out cross validation on the extracted fingerprint characteristic value, the group delay characteristic value and the identity identification model through using a convolution nerve network algorithm so as to realize identity identification of a user. In the invention, through collecting a fingerprint characteristic of the user and finger portion dielectric spectrum characteristic information, the identity identification is performed; and through using a multimodal fusion identity identification algorithm based on a convolution nerve network, the identity identification is performed and identity identification accuracy is increased.

The invention discloses a method for estimating the low-frequency dielectric loss of a paper oil insulation system based on parameter identification. Firstly, an XY model is used for simulating the polar characteristics of the transformer paper oil insulation system, a paper oil insulation system XY model equivalent circuit is established, and a relation expression among the circuit parameter, the characteristic quantity complex capacitance and the dielectric loss factor of the XY model equivalent circuit is established; a frequency domain dielectric spectrum method is used for measuring the complex capacitance and the dielectric loss factor of the paper oil insulation system of a field transformer; parameterization is conducted on the equivalent circuit model through the measured complex capacitance of the high-frequency section and the dielectric loss characteristic quantity, and a mathematical optimization model of parameter estimation is established; an improved particle swarm optimization algorithm is used for distinguishing the parameter value of the XY model equivalent circuit with four polar branch circuits; finally, the distinguished parameter value of the XY model equivalent circuit is used for calculating the complex capacitance and the dielectric value of the low-frequency section of the paper oil insulation system, and a frequency domain dielectric spectrum in a wide range is obtained. According to the method for estimating the low-frequency dielectric loss of the paper oil insulation system based on parameter identification, the paper oil insulation state of the large power transformer can be rapidly estimated based on the frequency domain dielectric spectrum method.

The invention discloses an annular arrangement type multi-needle biological tissue dielectric spectrum characteristic measuring probe, which comprises a base, wherein a plurality of needle type electrodes, a change-over switch and an excitation end and measuring end interface are arranged on the base; the plurality of needle type electrodes are arranged on two concentric circles of an inner ring and an outer ring formed on the base at equal interval and is perpendicular to the base to serve as excitation electrodes and measuring electrodes; and the electrodes of the same function are internally connected through copper wires on the base and are connected with the excitation end and measuring end interface through the change-over switch. The probe also comprises a calibration box which is matched with the probe for use. The invention also discloses an implementation method for biological tissue dielectric characteristic measurement by using the probe. The problem of strict requirement on shapes of tissues to be measured by the conventional measuring device is effectively solved, so that the electrical impedance measurement on the tissues of irregular shapes or the tissues difficultto cut is made possible.

The invention provides an open-ended coaxial probe and connection cable for measuring a dielectric spectrum property of biological tissues, and a corresponding instrument calibration method according to high-precision and wide-broadband measurement requirements on the dielectric property of in-vitro or in-vivo biological active tissues which are soft, small in volume and irregular in appearance. The open-ended coaxial probe comprises an inner conductor and an outer conductor which are concentrically arranged; the ratio of the radius of the inner conductor to the radius of the outer conductor is 3: 10; polytetrafluoroethylene is filled between the inner conductor and the outer conductor and a plating layer is arranged on the surface of the outer conductor. The connection cable is mainly composed of an N-type connector and a coaxial cable. The probe is calibrated by utilizing a phase cancellation method and is used for measuring the dielectric property of the biological active tissues at 1-200 MHz. Meanwhile, in order to increase the reliability of measured data, a calibration box which is used with the open-ended coaxial probe is provided; and a method for measuring the dielectric property of the biological tissues can be carried out by using the open-ended coaxial probe.

The invention discloses an experimental method for insulation wetting and aging evaluation research of winding models. Firstly, an experimental platform is set up; secondly, winding models with different wetting and aging degrees are prepared; thirdly, a frequency-domain dielectric spectrum curve database of the different wetting and aging degrees of the winding models at reference temperature isobtained; fourthly, frequency-domain dielectric spectrum test and reduction is carried out on a winding model within unknown wetting and aging degree; fifthly, the similarity between the frequency-domain dielectric spectrum test result and the frequency-domain dielectric spectrum curves in the database is calculated; and finally, the wetting degree and aging degree of the unknown winding model areobtained. According to the experimental method, a frequency-domain dielectric spectrum curve database of the different wetting and aging degrees of the winding models is established to evaluate the wetting degree and aging degree of windings, and a reference can be provided for the evaluation research of the wetting degree and aging degree of transformer windings.

The invention relates to the technical field of analysis and detection, in particular to a method for identifying honey varieties based on an attenuated total reflection terahertz dielectric spectrum. The method comprises the steps of at first conducting terahertz scanning on a honey sample of which variety is known and obtaining a terahertz time-domain spectrogram, then transforming the terahertz time-domain spectrogram into a terahertz frequency domain spectrogram through Fourier transformation, conducting calculation to obtain the terahertz dielectric spectrum of the honey sample of which variety is known and conducting principal component analysis according to the terahertz dielectric spectrum to establish a PCA-DA model of the honey sample of which type is known; finally adopting the same method to conduct detection on honey sample to be tested to obtain a terahertz dielectric spectrum, then conducting identification on the terahertz dielectric spectrum according to the PCA-DA model, and the variety identified by the PCA-DA model is the variety of the honey of which the variety is unknown. According to the method for identifying honey varieties based on the attenuated total reflection terahertz dielectric spectrum, only terahertz spectrum of the unknown honey needs to be collected, and then identification can be conducted through the model; meanwhile, the method for identifying honey varieties based on the attenuated total reflection terahertz dielectric spectrum has the characteristics and advantages that detection speed is high, operation is convenient, no chemical agent is polluted, both time and labor are saved, and accuracy is high.

It has been found advantageous to deploy coiled antennas as transmitters and receivers for acquiring the dielectric spectrum of materials. This method of impendence spectroscopy has been used to determine the concentration of glucose and other small polar molecules in vitro, as well as in vivo by placement on the antennas so that transmission is through the tissue, as for example on opposite sides of an organ or body part. The optimum selection of antenna coils permits deeper penetration into tissue for glucose detection, improves the SNR as well as expands the spectral range for greater accuracy and precision, to enable continuous non-invasive monitoring for either improved patient or automated management of diabetes.

The invention discloses a fitting algorithm for the moisture content of an oil paper insulation system and relates to the field of fitting algorithms for the moisture content rate of oil paper insulation systems. An effective numerical calculation algorithm is provided for assessment of the moisture content rate of the oil paper insulation system. According to an oil paper insulation frequency domain dielectric spectrum quantification calculation formula and a parallel-connection coefficient, a frequency domain dielectric spectrum of insulation of aged or damp oil paper is calculated and fitted with an actual-measurement frequency domain dielectric spectrum to obtain the moisture content of the insulation system of oil paper to be tested; the moisture content of an insulation paper plate in the oil paper insulation system is quantitatively diagnosed, and meanwhile oil paper insulation databases different in temperature and different in moisture content do not need to be established through a large number of experiments; the fitting algorithm can be applied to a power transformer and electric equipment which adopts the oil paper insulation system as main insulation.

The present invention discloses a system and method of vehicle cable terminal frequency domain dielectric spectrum experiment in an operation condition. The system comprises an experiment box body, and a cable terminal sample body, an insulation state detection unit, a cable terminal sample body, a frequency domain dielectric spectrum test system and a temperature regulation system 1 arranged in the experiment box body. The cable terminal sample body 21 is a cable terminal through processing, a hollow cylinder with small diameter is drilled out from the center of an internal cable core 31, and a resistance heating bar 32 passes through a hollow cylinder center and is connected with a radio-frequency power supply 6 through a wire. A function for simulation of temperature operation of cable in the load condition is realized. The obstacle caused by high cost and large size of the operation environment of a current phytotron simulation cable for the cable dielectric spectrum experiment is overcome so as to satisfy the research need, and the simple and practicable system and method of the vehicle cable terminal frequency domain dielectric spectrum experiment in the operation condition are provided.