52 results about "Resistivity distribution" patented technology

The invention belongs to the technical field of semiconductor device performance testing, and particularly relates to a VCSEL epitaxial wafer resistivity distribution measuring method and system, and the method comprises the steps: constructing a three-dimensional discretization model representing an epitaxial wafer and an unknown parameter vector containing the vertical resistivity, the top transverse resistivity and the substrate leakage junction nonlinear resistance; a physical response function is defined, the vector is iterated through a discrete point fitting algorithm, so that the total residual error between the analog voltage difference output by the function and the actually measured voltage value under the cross-order-of-magnitude current is minimum, and the real vertical resistivity is extracted from the optimal parameter vector; and obtaining the vertical resistivity of each point on the two-dimensional test point grid so as to generate a distribution diagram and carry out anomaly detection. According to the invention, the problem of measurement distortion caused by the leakage defect of the substrate is solved, and the measurement accuracy of the vertical resistivity is improved.

The invention relates to the technical field of data processing, discloses an earth and rockfill dam leakage positioning method based on joint inversion and data fusion, and aims to solve the problems of limitation and non-uniqueness of an existing single geophysical prospecting method in leakage hidden danger positioning. Converting the first apparent resistivity into a first apparent resistivity; second apparent resistivity distribution of the earth-rock dam is obtained through a high-density electrical method; acquiring electromagnetic wave velocity distribution by adopting a ground penetrating radar method, and converting the electromagnetic wave velocity distribution into third apparent resistivity; performing data standardization processing on the apparent resistivity to obtain standardized apparent resistivity data; performing dimension reduction fusion on the standardized apparent resistivity data corresponding to each apparent resistivity by adopting a principal component analysis method to obtain simulated apparent resistivity distribution; and determining the position of the leakage hidden danger channel in the earth-rock dam based on the pseudo-apparent resistivity distribution. The method improves objectivity, accuracy and reliability of leakage positioning, and is particularly suitable for danger removal and reinforcement of earth and rockfill dams.

The invention provides a coal rock resistivity dynamic real-time testing device and method in a water injection process, the device comprises a measuring electrode, a resistivity measuring system, a data acquisition system and a data processing system, the measuring electrode is used for forming an electrode network and is in contact with coal rock, and the resistivity measuring system is used for measuring the resistivity of the coal rock. The resistivity measurement system is used for measuring the resistivity of the coal rock; the data acquisition system is used for acquiring resistivity data in real time; and the data processing system is used for carrying out inversion processing on the collected resistivity data to obtain a resistivity distribution image in the coal rock. According to the invention, continuous or quasi-continuous resistivity measurement is carried out on a water injection area by arranging a specific electrode array according to the change rule of the resistivity of the coal rock along with factors such as moisture content, pore structure and ion migration in the water injection process, and the resistivity of the water injection area is measured through a data acquisition and processing system. The water injection state, the permeation path and the wetting effect in the coal rock are dynamically reflected in real time, and a scientific basis is provided for real-time adjustment and optimization of water injection parameters.

The invention provides an equivalent circuit analysis method and system for soil resistance heating efficiency, and relates to the technical field of soil remediation. Resistivity distribution data and salt content distribution data of a pile space are obtained; calculating the ionic conductivity according to the salt content distribution data, and calculating the target conductivity of each grid unit; constructing a topological graph, and constructing a weighted adjacent matrix based on the topological graph; constructing a degree matrix according to the degree of each graph node to obtain a feature value sequence and a feature vector corresponding to each feature value; extracting a second small feature value from the feature value sequence as a connectivity index, and marking a mutation position as a weak connection interface; the blocking factor is determined by counting the number of graph nodes located at the weak connection interface, the equivalent circuit transmission efficiency representing the soil resistance heating efficiency is calculated based on the negative correlation between the connectivity index and the blocking factor, and accurate quantitative evaluation of the heterogeneous soil resistance heating efficiency is achieved.

The invention provides a floating photovoltaic power station grounding resistor fault positioning method and device, the method is applied to a controller in a fault positioning system, and the fault positioning system further comprises a grounding grid of a floating photovoltaic power station, a sensing network formed by deploying sensors at key nodes of the grounding grid, and a signal generator. The method comprises the following steps: in response to a received fault positioning instruction, triggering a signal generator to inject a high-frequency test current signal into a grounding grid; acquiring a current-voltage data set through a voltage response signal of each key node acquired by a sensing network; based on the current-voltage data set, resistivity distribution reconstruction is carried out by adopting an impedance imaging algorithm, and a three-dimensional resistivity distribution diagram of the grounding grid is generated; and according to the three-dimensional resistivity distribution diagram, positioning an abnormal region with a resistance value exceeding a preset threshold value in the grounding grid. According to the method, three-dimensional visual imaging of resistivity distribution in the grounding grid and accurate positioning of an abnormal area are realized.

The present application belongs to the technical field of semiconductor device performance testing, and particularly relates to a VCSEL epitaxial wafer resistivity distribution measurement method and system, which comprises the following steps: constructing a three-dimensional discretization model representing the epitaxial wafer and an unknown parameter vector containing a vertical resistivity, a top lateral resistivity and a nonlinear resistance of a substrate leakage junction; defining a physical response function, and through a discrete point fitting algorithm, iterating the vector to minimize the total residual between the simulated voltage difference output by the function and the measured voltage value under a cross order of magnitude current, and extracting the real vertical resistivity from the optimal parameter vector; and obtaining the vertical resistivity of each point on a two-dimensional test point grid to generate a distribution map and perform anomaly detection. The present application solves the measurement distortion problem caused by substrate leakage defects and improves the measurement accuracy of the vertical resistivity.

The application provides a kind of early warning system and method of radial artery compression hemostat based on multiple sensors, belongs to complication early warning technical field.The method comprises the following steps: S1, multiple types of physiological signals in the radial artery compression area are synchronously collected and digitized;S2, the temperature at the proximal end and the temperature at the distal end are subjected to discrete wavelet transform;the pulse signal is subjected to time domain analysis, and the pulse amplitude is extracted;S3, a temperature distribution model of the compression area is constructed based on the temperature difference signal;S4, the resistivity distribution of the compression area is reconstructed through the electrode impedance signal, and the bleeding position is located;S5, the pressure change rate is calculated based on the pressure digital signal;the pulse amplitude attenuation rate is calculated based on the pulse amplitude;the pressure change rate, the temperature gradient vector, the pulse amplitude attenuation rate and the bleeding index are fused through a weighted summation formula, and a comprehensive risk value is obtained.The application improves the complication-related parameter coverage rate through multiple sensors, and improves the timeliness and accuracy of complication early warning.

This application provides an automatic silicon core testing device, relating to the field of polysilicon technology. It includes: a positioning mechanism for positioning at least one silicon core, the silicon core being arranged laterally or vertically and capable of rotating about its own axis; a size measuring mechanism for measuring the dimensions of the silicon core; a resistivity measuring mechanism for measuring the resistivity distribution of the silicon core; and a driving mechanism for contacting or separating the resistivity measuring mechanism from the silicon core. This automatic silicon core testing device solves the technical problem that current silicon core testing mainly relies on manual sampling, which suffers from low efficiency, high missed detection rate, large human measurement errors, and the possibility of substandard silicon cores being used despite passing sampling. This leads to substandard silicon cores entering the production process and even causing serious accidents such as furnace collapse and silicon core detachment, resulting in huge economic losses.

The invention relates to the technical field of nondestructive testing of geotechnical engineering anchoring structures, in particular to an anchor cable grouting quality detection method based on electrical resistance tomography, which comprises the following steps: establishing a refined electrical simulation model, performing differential insulation parameter optimization design on a free section and an anchoring section of an anchor cable, and effectively inhibiting current shunt; optimizing the spatial arrangement of the electrode array based on targets such as the signal-to-noise ratio and the sensitivity field uniformity; in an inversion algorithm, the steel strand and an insulating layer are used as prior constraints, and the dynamic identification capability is improved in combination with time sequence regularization; and finally, performing intelligent comparative analysis on the resistivity distribution obtained by inversion and a pre-constructed grouting body resistivity characteristic reference library, and outputting a quantitative test result and a visual image containing defect positions, types, sizes and overall quality grades. According to the invention, high-precision, three-dimensional and quantitative nondestructive testing and dynamic monitoring of the grouting quality of the anchor cable are realized.

A method for evaluating a silicon single-crystal ingot is provided that reduces the time required to evaluate the resistivity variation in the crystal length direction and improves wafer yield. In the method for evaluating a silicon single-crystal ingot according to the present embodiment, a counter doping is performed by adding a sub-dopant during the pulling of silicon single-crystals ingot by the CZ method, resistivity on a side surface in a crystal length direction is measured by a four-point probe method in a silicon single-crystal ingot 1 state after the silicon single-crystal ingot is pulled up, and a reject range is determined on the basis of a resistivity distribution in the crystal length direction.

A method for forming a semiconductor structure includes: forming a buried layer, then pre-treating a substrate, the pre-treating including one or both of element precipitation treatment on a first surface and element blocking treatment on a second surface; and forming an epitaxial layer covering the first surface after pre-treating the substrate. If the second surface is subjected to element blocking treatment, the probability of elements in the substrate and the buried layer escaping from the second surface is reduced, which correspondingly reduces the probability of self-doping during epitaxial layer growth, thereby making the diffusion resistivity distribution curve closer to the substrate region. If the first surface is subjected to element precipitation treatment, the probability of element neutralization between the elements in the substrate and the buried layer is reduced, thereby making the diffusion resistivity distribution curve closer to the substrate region. In summary, using either or both of element precipitation treatment and element blocking treatment can make the diffusion resistivity distribution curve closer to the substrate region.

The application discloses a cement mixing pile hole forming uniformity detection method based on resistivity three-dimensional imaging, and particularly relates to the field of nondestructive testing of engineering materials, and is used for solving the problem that the general resistivity inversion method is blurred in detecting the real defect boundary due to the smoothness constraint when detecting the discrete non-uniform body in the cement mixing pile, and false abnormal transition zones are prone to be generated, thereby affecting the detection accuracy; effective data is obtained by acquiring resistivity measurement data and screening, a partition constraint inversion strategy is adopted based on the effective data to weaken the smooth constraint on the core area of the pile body and to retain the conventional smooth constraint on the surrounding medium area, so as to generate a three-dimensional resistivity distribution result, the density clustering and spectral density analysis are extracted and utilized to verify the time and space of the electrical property mutation boundary, the continuous false abnormal transition zone is removed through similarity matching to generate a purified resistivity distribution result, and the uniformity detection conclusion is output based on the result, and the accuracy of the internal non-uniform defect recognition of the cement mixing pile is improved.

The present invention provides a susceptor with improved responsiveness of temperature control, and an object thereof is to obtain a high-quality wafer product without impairing productivity. Provided is a susceptor that generates heat by induction heating, the susceptor including a graphite base material and a ceramic coating layer. The graphite base material exhibits a variation (ρmax / ρmin) Of an in-plane electrical resistivity distribution of the graphite base material at room temperature of 1.00 to 1.05 and a rate of high-temperature change (ρ1600 / ρ800) of electrical resistivity at 1600° C. to that at 800° C. of 1.14 to 1.30.

This invention provides a method and system for predicting the state of a substation affected by stray current fluctuations. Based on train operation data, a digital twin traction power supply system model integrating train dynamics and traction arc characteristics is used to generate a stray current disturbance signal containing transient pulse components. Based on earth resistivity distribution data and the stray current disturbance signal, a three-dimensional finite element underground stray current diffusion model with adaptive mesh refinement is used to obtain the current component flowing into the substation grounding grid. Based on the current component and substation operation data, a digital twin model of the substation's electromagnetic-thermal coupling, explicitly modeled with the core lamination structure and oil-cooled convection channel, is used to make predictions, obtaining the substation's bias magnetization prediction results and temperature rise prediction results. This invention comprehensively considers multi-source heterogeneous data and combines simulation technology for the entire chain of subway traction, earth, and power grid substations, which can improve the risk prediction results of substations.

This invention discloses a three-dimensional resistivity imaging probe and system for ultra-deep directional boreholes, belonging to the field of engineering exploration technology. The downhole probe adopts an inner-lined scanning structure with longitudinal grooves on its outer shell surface. A probe array is installed within the grooves, and the exposed ends of the probes are radially scattering, forming inner-lined contact with the borehole wall. The probe integrates an attitude measurement and probe extension module, a power supply module, and a data storage and transmission module. The system includes a ground control and processing unit, a cable transmission unit, and the downhole probe itself. An excitation electric field is generated by the power supply electrodes, and the probe array collects borehole wall voltage and current data. Combined with a three-dimensional resistivity imaging model and image reconstruction algorithm, an image of the circumferential cylindrical resistivity distribution of the borehole is generated. This invention achieves in-situ, high-precision three-dimensional resistivity imaging of boreholes, accurately identifying the spatial distribution of faults, fissures, and weak interlayers around the borehole, providing reliable technical support for risk identification and assessment in deep earth engineering.

The application discloses a kind of ground electrode in time domain finite difference simulation soil ionization effect characterization method, including obtaining the geometry of the ground electrode to be characterized, soil characteristics, environment and excitation source parameters, construct electrode in FTDT simulation model;The model is meshed, the absorption boundary condition and simulation total length are determined and initialized;Current density and electric field intensity around electrode are calculated, and soil resistivity is updated;The total resistance of electrode under the distribution of current soil resistivity is calculated, and the equivalent radius of electrode is calculated correspondingly;The correction factor of time domain finite difference is calculated using the equivalent radius of electrode, and then the vertical electric field component parameter of electrode is corrected;When the current simulation length reaches the simulation total length, the ground electrode top voltage, resistance, equivalent radius characterizing soil ionization effect are output;Method can accurately characterize soil ionization effect under coarse grid, greatly improve the calculation efficiency.

The application provides a slow-release device, a rubidium-titanium potassium phosphate oxide crystal and a preparation method thereof, and belongs to the technical field of electro-optic crystals and nonlinear optical crystals. The application provides a slow-release device, which comprises a hollow inner tube and a hollow outer tube sleeved outside the hollow inner tube; the hollow inner tube and the hollow outer tube are both closed structures provided with slow-release holes at the top; the diameter of the slow-release hole is 0.3-3 mm. The slow-release device provided by the application can avoid crystal cracking, and the prepared rubidium-titanium potassium phosphate oxide crystal has the advantages of high resistivity and uniform resistivity distribution.

This invention belongs to the field of semiconductor manufacturing technology and discloses a method and system for adjusting the PVA water absorption roller wafer drying process based on reinforcement learning. The sensor fusion module builds a full-dimensional perception system, accurately capturing four-dimensional state data of the PVA roller, wafer, environment, and actuator through multiple types of sensors, and outputting a unified state vector after processing by a cross-modal fusion algorithm. The reinforcement decision module combines expert knowledge graphs and deep reinforcement learning, adopting a dual-drive architecture and a dynamic multi-objective reward function. It can accelerate model convergence by relying on expert experience, and dynamically balance drying quality, efficiency, energy consumption, and equipment wear, outputting the globally optimal combination of parameters such as roller pressure and speed, effectively reducing wafer moisture residue and scratch defect rate. The quality feedback module constructs a four-dimensional real-time evaluation system based on physical, optical, electrical, and temporal trends, quantifying drying quality from multiple dimensions such as contact angle, surface defects, and resistivity distribution, and providing real-time feedback.

The invention discloses an excitation signal extraction method, device and equipment and a storage medium, and relates to the technical field of underground structure detection, and the method comprises the steps: obtaining aviation transient electromagnetic original signal data, and carrying out the preprocessing of the aviation transient electromagnetic original signal data, and obtaining target electromagnetic signal data; obtaining an early time window, and obtaining early electromagnetic signal data according to the early time window and the target electromagnetic signal data; performing inversion according to the early electromagnetic signal data to obtain underground medium resistivity distribution data, and obtaining full-time transient electromagnetic conduction response data according to the underground medium resistivity distribution data; and performing time domain difference operation according to the target electromagnetic signal data and the full-time transient electromagnetic conduction response data to obtain an excitation signal. According to the invention, more accurate excitation signals can be extracted.

The invention discloses a cement mixing pile pore-forming uniformity detection method based on resistivity three-dimensional imaging, and particularly relates to the technical field of engineering material nondestructive testing. The method is used for solving the problem that a real defect boundary is fuzzy due to smoothness constraint when a general resistivity inversion method is used for detecting a discrete non-uniform body in a cement mixing pile, and meanwhile, a false abnormal transition region is easily generated, so that the detection accuracy is influenced. Effective data are obtained by acquiring resistivity measurement data and screening, smooth constraint of a pile body core area is weakened by adopting a partition constraint inversion strategy based on the effective data, and conventional smooth constraint of a peripheral medium area is reserved to generate a three-dimensional resistivity distribution result. According to the method, the electrical abrupt change boundary is extracted and subjected to space-time verification by utilizing density clustering and spectral density analysis, then a continuous false abnormal transition region is eliminated through similarity matching to generate a purified resistivity distribution result, and a uniformity detection conclusion is output based on the result, so that the accuracy of identifying the non-uniform defect in the cement mixing pile is improved.

[Problem] To provide an epitaxial silicon wafer with low in-plane resistance variation and low distortion, and a manufacturing process for it. [Solution] An epitaxial silicon wafer 1 with a diameter of 300 mm and a thickness of 761 to 795 µm comprises: a bulk silicon substrate 2 doped with boron and exhibiting a resistivity of 8 to 20 mΩ cm; an epitaxial silicon film 3 formed on a front surface 2a of the bulk silicon substrate 2; and a back oxide film 4 formed on a back surface 2b of the bulk silicon substrate 2. The epitaxial silicon film 3 is configured to have a thickness of 1.7 to 2.7 µm, is boron doped, has a resistivity of 8 to 12 Ω cm, and exhibits an in-plane resistivity distribution of 3% or less. The reverse oxide film 4 has a thickness of 50 to 150 nm.

The invention discloses a landfill leakage detection method and system based on a transient electromagnetic method, and belongs to the technical field of environment monitoring and geophysical exploration. The method comprises the following steps: arranging a gridding transient electromagnetic detection array on an impermeable layer of a landfill; synchronous signal acquisition is carried out by setting transmitting frequencies in a layered manner; adaptive filtering and denoising, metal interference correction and terrain correction are carried out on the collected data; establishing an inversion model by using an online sequential extreme learning machine to obtain a three-dimensional resistivity distribution image; and recognizing a leakage area according to the low-resistance abnormal features and performing three-level quantitative evaluation. The invention further discloses a corresponding detection system which comprises a transient electromagnetic detection array module, a signal acquisition module, a data processing module and a leakage evaluation and early warning module. Through high-precision synchronous control, self-adaptive interference suppression and an intelligent inversion algorithm, rapid and accurate detection and graded early warning of the leakage position, range and degree of the landfill are realized.

The invention belongs to the field of geophysical exploration, and relates to a well frequency domain electromagnetic method three-dimensional anisotropic resistivity robust imaging method, which comprises the following steps of: adopting a well probe rod with a built-in three-axis orthogonal transmitting coil and a three-component receiving sensor to perform point-by-point movement measurement at a preset interval along a well axis; at each measuring point, the probe rod in the well is stopped, and the three orthogonal emission shafts are independently excited in sequence; in the excitation process of each transmitting shaft, a plurality of sine wave currents with specific frequencies are introduced in sequence, the transmitting magnetic moment is recorded, and the actually measured electromagnetic response induced in the receiving coil is synchronously collected; according to the method, actually measured electromagnetic response is preprocessed, inversion is performed by adopting a Bayesian geostatistics inversion method based on posterior confidence constraint in combination with actually measured electromagnetic response data, anisotropic resistivity distribution in a three-dimensional space around a well is obtained, and the robustness of frequency domain electromagnetic imaging in the well is effectively improved.

The invention belongs to the technical field of geophysical exploration, and provides a three-dimensional resistivity detection system and method based on irregular measuring line multi-device fusion, and the system comprises at least one irregular measuring line arranged on the ground, a coordinate collection device, a high-density electrical method instrument, and a data processing device. The irregular measuring line comprises a first side wing, an end part and a second side wing which are connected in sequence, the free end of the first side wing and the free end of the second side wing are located on the same side of the end part, and a half-surrounded area formed by the irregular measuring line covers a region of interest; the high-density electrical method instrument carries out high-density electrical method measurement on at least one irregular measuring line according to at least two resistivity measurement modes; the data processing device fuses the data acquired by the high-density electrical method in the at least two resistivity measurement modes to obtain fused data, and obtains a three-dimensional resistivity distribution model of the underground medium in the region of interest based on the fused data; the invention also provides a three-dimensional resistivity detection method. According to the invention, the detection precision and reliability of the three-dimensional anomalous body are improved.

The invention provides an automatic scanning device and method for the volume resistivity of a conductive composite material, and belongs to the field of civil engineering material detection and automatic testing. The device comprises a portal frame module, a self-adaptive conductive bearing platform, a three-axis linkage scanning terminal, a visual perception module and an intelligent control system. The self-adaptive conductive bearing platform serves as a common lower electrode, a micropore conductive elastomer layer is arranged on the surface of the self-adaptive conductive bearing platform, and the elastomer layer deforms through negative pressure adsorption so as to be tightly attached to the bottom of the test piece; the visual perception module identifies the contour of a test piece and constructs a digital coordinate system, and the three-axis linkage scanning terminal drives the elastic pressurization probe assembly at the tail end to scan and measure the upper surface of the test piece under the coordination of the intelligent control system. According to the method, the problems of tedious bottom contact processing, low manual measurement efficiency, sparse data and poor consistency in a traditional method are solved, and efficient and accurate evaluation of the volume resistivity distribution of the conductive composite material is realized.

The invention relates to the technical field of time-frequency electromagnetism, and discloses a resistivity and polarizability joint inversion method based on time-frequency domain electromagnetic exploration, which comprises the following steps: acquiring time-frequency domain electromagnetic field parameters of an underground medium by using a time-frequency electromagnetic method observation system; based on the time-frequency domain electromagnetic field parameters of the underground medium, a time-frequency domain joint inversion model of the resistivity and the polarizability is constructed, and forward modeling calculation of the joint inversion model adopts a one-dimensional analytical solution of a layered medium geoelectric model; and performing quasi-two-dimensional constraint inversion calculation on the joint inversion model by adopting a nonlinear conjugate gradient method to obtain resistivity distribution and polarizability distribution of the underground medium. The correctness and effectiveness of the method are verified through a known geoelectric model and an actually measured data example in typical mineral exploration. Compared with a result obtained by independently adopting time domain or frequency domain inversion, the time-frequency domain electromagnetic joint inversion fully fuses the advantages of the time domain and the frequency domain, so that the resistivity and polarizability models can reflect the structural characteristics of the ore body and the rock stratum more accurately.

The utility model discloses an anti-interference engineering transient electromagnetic instrument, which comprises a shell, a transmitting unit, a receiving unit and a control unit, wherein the transmitting unit, the receiving unit and the control unit are arranged in the shell; the transmitting unit comprises a transmitter and a transmitting coil; the receiving unit comprises a shielding assembly and a signal receiving assembly, the shielding assembly is of a multi-layer shielding structure, and each layer of shielding structure correspondingly absorbs interference signals of different frequencies; the control unit comprises a main control board, and the main control board is in signal connection with the transmitting unit and the receiving unit. Interference of different frequency bands is shielded and filtered out through the shielding assembly, then attenuation characteristics of a secondary field are detected through the signal receiving assembly, underground resistivity distribution is inversed in combination with time domain analysis, then underground electrical structure characteristics are analyzed, a traditional single-layer metal cover is replaced with layered gradient shielding, and interference of different frequency bands is filtered out in a targeted mode.

This invention pertains to the field of coal mine mining and modification technology, specifically relating to a tomographic imaging-based inversion system and method for retrieving fracture networks in artificially modified coal seams. This invention involves deploying a resistivity detection electrode array in the artificially modified coal seam region, using resistivity tomography to collect real-time data on the coal seam resistivity distribution, and then combining this data with artificial modification process parameters to construct a correlation model between the fracture network and resistivity. An inversion algorithm is then used to reconstruct the spatial distribution, development range, and connectivity characteristics of the coal seam fractures. Furthermore, this invention is relatively easy to operate, has high inversion accuracy, and can track the dynamic evolution of coal seam fractures in real time during the artificial modification process, providing crucial data support for optimizing coal mine gas extraction efficiency and assessing coal seam stability.

The application relates to a time-domain electromagnetic space-time double-gradient resistivity imaging method, device, computer equipment, computer readable storage medium and computer program product. The method comprises the following steps: acquiring transient electromagnetic method data to be processed, wherein the data to be processed comprises electric field component attenuation data of m*n measuring points, and a far zone condition is met between the m*n measuring points and a long wire source; acquiring a spatial gradient expression of apparent resistivity and a time gradient expression of apparent resistivity; performing finite difference fusion based on the spatial gradient expression of resistivity and the time gradient expression of apparent resistivity to obtain a gradient resistivity expression; and generating a resistivity distribution map of a subsurface medium according to the data to be processed and the gradient resistivity expression. The abnormal body boundary description accuracy is improved.

The application discloses a silicon wafer and a preparation method thereof, a solar cell, a photovoltaic module and a power station. The silicon wafer is used for preparing the solar cell, is a quadrilateral structure obtained by cutting a circular silicon rod, and comprises the following steps: at least three angles in the quadrilateral structure are from an inner region on a cross section of the circular silicon rod, wherein the inner region on the cross section is a region with a resistivity lower than a set threshold value on the cross section, and the set threshold value is determined by the resistivity of a region with a sharp increase in the resistivity of the circular silicon rod; and the resistivity of the silicon wafer is in a decreasing distribution along a specific pair of diagonals in the quadrilateral structure. The design of the silicon wafer structure is that the proportion of the high-resistivity region is reduced, and the resistivity distribution is relatively uniform.