36 results about "Dielectric spectroscopy" patented technology

A method for measuring membrane potential using dielectric spectroscopy is described. A new theoretical model allows for the determination of membrane potential from low-frequency impedance measurements to provide a non-evasive method which is both rapid and inexpensive.

The present invention relates to a method for measuring physical property values of a cell based on dielectric spectroscopy and based on modeling electrical characteristics such as electric conductivity, electric permittivity, dielectric constant change, and dielectric relaxation expressions in order to obtain membrane capacitance and cytoplasmic conductivity values of the cell.

The invention discloses a non-contact method for measuring the frequency-domain dielectric spectrum of a composite material, which comprises the following steps: 1. Input test voltage, frequency range and frequency interval parameters on a dielectric spectrum tester through preset software as required; 2. Place the composite material between the test electrodes, adjust the height of the upper electrode, so that the distance between the electrodes is greater than the thickness of the composite material, that is, there are two dielectrics of composite material and air between the electrodes; 3. Apply frequency conversion voltage excitation to the electrodes, At the same time, the current is measured, and the complex capacitance of the air and the composite material is calculated at the corresponding frequency; 4. The composite material is taken out from between the electrodes, and there is only air as a medium between the electrodes. Apply variable-frequency voltage excitation to the electrodes, measure the current at the same time, and calculate the complex capacitance when there is only air at the corresponding frequency; 5. Calculate the complex dielectric constant and dielectric loss tangent of the composite material according to the formula. It has the advantages of measuring the polarization loss of the material itself and high accuracy.

A sensing element (1) for a measurement system suitable for dielectric impedance spectroscopy, wherein the sensing element (1), at least in one operating state of the sensing element (1), comprises atleast first one microstrip conductor (2), consisting of a first conductor strip (3) for a measurement signal, a first dielectric substrate and a first ground surface (5), wherein the first conductorstrip (3) may be applied from the outside and over an area to a container containing a dielectric material sample to be measured, preferably to a pipe, a vessel or a bag.

The invention discloses a method for quickly detecting the fat content of bovine milk based on a dielectric spectrum technique. According to the method for quickly detecting the fat content of the bovine milk based on the dielectric spectrum technique, dielectric spectrums (relative dielectric constant spectrums and dielectric loss factor spectrums), in certain one radio-frequency / microwave range of one batch of bovine milk samples are obtained by utilizing a network analyzer (or an impedance analyzer) and a coaxial probe; characteristic dielectric variables which express the fat content of the bovine mink are extracted from the dielectric spectrums; linear or nonlinear detection models for detecting the fat content of the bovine milk are established based on the dielectric spectrums in the whole radio-frequency / microwave range or the extracted characteristic dielectric variables; the models are inspected; the model of which the prediction-set root-mean-square error is minimal is used as an optimal model for detecting the fat content of the bovine milk. The dielectric spectrum of a bovine milk sample of which the fat content is unknown is measured; the numerical values of the characteristic dielectric variables are substituted into the optimal model, so that the fat content of the sample can be calculated. The method for quickly detecting the fat content of the bovine milk based on the dielectric spectrum technique has the advantages that the detection is convenient and quick, the operation is simple, the precision is high, and the on-line and real-time detection can be realized.

The invention discloses a method for rapidly detecting the content of polar components in frying oil. The method comprises the following steps: taking linear measuring points of a to-be-detected frying oil sample by utilizing a frequency domain dielectric spectroscopy tester, obtaining a compound dielectric constant of the frying oil sample, wherein the compound dielectric constant comprises a real part epsilon' and an imaginary part epsilon'', and forming dielectric constant-frequency and dielectric loss-frequency spectrums; and performing spectrum unfolding, fitting the actually measured dielectric constant, and judging the content of the polar components in frying oil according to an extracted characteristic parameter tau. According to the method disclosed by the invention, the content of the polar components in the frying oil can be rapidly measured in case of a nondestructive sample, and a reliable basis is provided for accurately evaluating the safety of fried foods.

The invention relates to the technical field of insulation detection for high voltage equipment, in particular to an insulation detection method for a high voltage bushing based on frequency domain dielectric spectroscopy. The method comprises the step that a frequency domain dielectric spectroscopy based test is adopted to detect insulation of the bushing. With the adoption of the method, an influence of a Garton effect on measuring of tan delta at low voltage is avoided; a real tan delta frequency curve of the bushing at 0.001-1000Hz and at the low voltage is acquired and used for judging an insulation state of the bushing; and compared with the traditional bushing adopting a single 50Hz frequency point tan delta to judge the insulation state of the bushing, the judgment accuracy is improved. The test and a measuring device of the method are simple in structure and easy to operate, and the difficulty that the test and the device are difficult to operate when the measuring of the tan delta of the bushing is conducted at 0.001-1000Hz and at high voltage is solved.

The invention discloses a method for evaluating ageing state of paper oil insulation. The method is characterized by comprising the following steps of: 1, measuring a relative dielectric constant and a dielectric loss factor of a paper oil insulation test product by adopting a frequency domain dielectric spectroscopy method; 2, establishing a composite exponential function relational expression of the relative dielectric constant and insulation paper polymerization of the paper oil insulation test product, and a composite exponential function relational expression of the dielectric loss factor and the insulation paper polymerization of the paper oil insulation test product; and 3, evaluating the ageing state of a paper oil insulation system by using the relational expressions. A device provided by the invention is simple in structure, is easily implemented, and is greatly improved in accuracy.

A method for characterizing the Curie temperature of barium strontium titanate ceramics based on up-conversion luminescence, the invention belongs to the field of preparation of rare earth-doped barium strontium titanate (BST) ceramics, and it aims to solve the problem of traditional dielectric temperature spectrum characterization of barium strontium titanate ceramics The Curie temperature method has strict requirements on the shape of the barium strontium titanate ceramic sample and the problem of damage to the sample caused by the treatment of the upper electrode. Characterization methods: 1. BaCO3, SrCO3 and TiO2 powders are mixed to prepare BST powder; 2. BST powder is dry-pressed and sintered to obtain BST ceramics; 3. Test the up-conversion luminescence spectra of BST ceramics at different temperatures. Make a curve of the luminous intensity at the luminous wavelength as a function of temperature, and the temperature corresponding to the point with the largest rate of change on the curve is the Curie temperature point. The characterization method based on the up-conversion luminescence of the present invention has no limitation on the shape, surface area and thickness of the test sample, and has high test accuracy.

The invention belongs to the field of insulation evaluation and diagnosis of an oil-immersed bushing and particularly relates to a dielectric spectroscopy test experiment method for an oil-immersed bushing under different aging. The method comprises steps: an oil-immersed bushing aging platform is built; the oil-immersed bushing is subjected to aging processing; temperature of an upper porcelain sleeve, a flange and a lower porcelain sleeve of the oil-immersed bushing is measured; according to the measured temperature, the temperature of an inner hot spot of the oil-immersed bushing is estimated; and according to the inner hot spot temperature, the degree of polymerization of inner insulation of the oil-immersed bushing is estimated; and the dielectric spectroscopy of the oil-immersed bushing is tested. The relationship between a frequency domain dielectric spectroscopy test result and oil immersed bushing aging can be effectively studied, the accuracy of diagnosing the insulation aging degree inside the oil-immersed bushing by the frequency domain dielectric spectroscopy method can thus be improved, and the applicability of the frequency domain dielectric spectroscopy method in field test and the operation safety and the operation stability of the oil-immersed bushing are improved.

An apparatus for estimating a property of a downhole fluid, the apparatus includes: a carrier configured to be conveyed through a borehole penetrating the Earth; a downhole fluid extraction device disposed at the carrier and configured to extract the downhole fluid; and a dielectric spectrometer disposed at the carrier and configured to transmit electromagnetic energy into the extracted downhole fluid at a plurality of frequencies and to measure a plurality of responses to determine a permittivity of the extracted downhole fluid as a function of frequency; wherein the permittivity is used to estimate the property.

The present invention disclosed the evaluation method of large -scale generators based on the frequency domain dielectric spectrum method.The high -voltage end of the test cable of the winding spectrum tester is connected to the ground end of the generator shell to the ground end of the test cable of the dielectric spectrum tester; set the parameters and start the test;The frequency characteristic curve ε‑f of the frequency of electricity is obtained through formula calculations to obtain the current main insulating medium loss cause incremental ΔtanΔN; the obtained medium loss causes increase ΔtanΔN, evaluate the aging state of the main insulation of the generator stator winding.The present invention is a non -broken test method. Its testing principle is simple and the wiring is convenient. It can accurately determine the medium loss ΔtanΔN of the medium loss cause of the main insulation of the generator stator winding group, thereby effectively evaluating the aging state of the generator.