2444 results about "Electric resistivity" patented technology

The invention discloses a dry-method electrode film and a preparation method thereof, an electrode and a battery, and belongs to the technical field of batteries. The method comprises the following steps: mixing polytetrafluoroethylene, an active substance and a conductive agent, and crushing to obtain a crushed mixture; performing primary airflow grinding and shearing on the crushed mixture to obtain a ground and sheared mixture; the primary shearing conditions are as follows: the airflow temperature is-10 to 10 DEG C, the airflow pressure is 0.7 to 0.9 MPa, and the rotating speed is 8000 to 12000 rpm; carrying out secondary airflow grinding, shearing and fibration on the ground and sheared mixture to obtain a fibration material; and carrying out secondary fibration treatment on the fibration material to obtain the dry-method electrode film. The method can significantly improve the tensile strength of the electrode film, improve the liquid absorption rate of the electrode and reduce the resistivity of the electrode.

The invention relates to the technical field of fault diagnosis of power electronic equipment, and particularly discloses a fault analysis and diagnosis method and system for a mining high-voltage frequency converter, and the method comprises the steps: collecting the skin effect depth and parasitic parameter drift distance in real time under a high-frequency working condition through a multi-physics field sensor array; constructing three-dimensional current density distribution of the conductor based on a non-Euclidean space mesh generation technology, and dynamically correcting the equivalent resistivity of the conductor in combination with a metamaterial database to calculate a dynamic eddy current loss characteristic value; optimizing and solving the parasitic parameter time-varying evolution equation by using a quantum annealing algorithm to obtain a voltage peak sensitivity characteristic value; inputting the characteristic value into a pre-trained deep residual shrinkage network diagnosis model for multi-modal fusion analysis, and outputting a fault risk assessment result; according to the method, the problem of parasitic parameter time-varying characteristic modeling in the vibration environment is innovatively solved, and early warning of hidden faults is achieved.

A hole-tunnel induced polarization water exploration structure construction method, comprising steps: arranging a plurality of forward boreholes (2) at intervals on an outer edge area of a tunnel face; respectively providing in each forward borehole (2) an in-hole exploration cable having a power supply electrode A (5) and a power supply electrode B (6); providing in an array a plurality of out-hole exploration electrodes, which are configured as a measurement electrode M (7) and a measurement electrode N (8), outside the area occupied by the forward boreholes (2) of the tunnel face, wherein the power supply electrodes form a power supply closed loop, and the measurement electrodes form a measurement closed loop. Also provided is an inversion method for a hole-tunnel induced polarization water exploration structure, comprising steps: acquiring hole-based initial observation data, and forming exploration observation data; establishing a corresponding initial resistivity model and a corresponding initial polarizability model, and carrying out a conventional inversion electrical method to obtain a resistivity inversion model; establishing a tunnel resistivity and polarizability clustering joint inversion objective function; and performing iterative inversion to obtain a final inversion result.

Metallization schemes involve atomic layer deposition (ALD) of molybdenum (Mo) and in some embodiments, ALD of Mo in a feature without a barrier layer. In some embodiments, deposition of the ALD Mo film may be followed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) of a Mo film. In some embodiments, the CVD or PVD Mo film is part of the metallization stack. In other embodiments, the CVD or PVD Mo film is deposited as a sacrificial overburden layer. In some embodiments, deposition of the ALD Mo film may be followed by CVD or PVD of another metal such as tungsten (W). In some embodiments, the CVD or PVD W film is part of the metallization stack. In other embodiments, the CVD or PVD W film is deposited as a sacrificial overburden layer.

The invention discloses a method for improving the heat dissipation performance of an AlGaInP red light Micro LED chip. The method comprises the following steps: S1, preparing an epitaxial structure: processing a substrate and a buffer layer, growing an etching barrier layer and an ohmic contact layer, and carrying out stacking epitaxy on a functional layer; s2, patterning the silicon-based substrate: preparing a dielectric layer and a metal structure; s3, diamond ohmic contact layer integration: processing a p-type conductive diamond film layer, and carrying out metal reflection and bonding; s4, removing the substrate and forming an n-type structure: stripping the substrate to be in n-type contact; s5, back-end process integration: preparing an electrode and an optical structure; according to the invention, the heat dissipation performance of the chip is significantly improved; the series resistance is reduced by 30%-50%; the resistivity of the p / n type diamond ohmic contact layer is reduced by 1-2 orders of magnitude compared with ITO; gaAs material light absorption and metal shading are avoided, and the red light transmittance is improved from 75% to more than 90% by combining with the micro lens array; the method is compatible with existing MOCVD, CVD and photoetching processes, large-scale production of wafers of 2-12 inches can be achieved, and the manufacturing cost is reduced.

The invention relates to the technical field of crystal material preparation, in particular to a ternary layered selenide Ge3Sb4Se7 semiconductor material and a preparation method thereof. The preparation method of the ternary layered selenide Ge3Sb4Se7 semiconductor material comprises the following steps that S001, germanium powder, antimony powder and selenium powder with the molar ratio being 3: 4: 7 serve as raw materials, the temperature is increased to 900-950 DEG C under the vacuum condition, and heat preservation is conducted for 12-24 h at the temperature; s002, after heat preservation is finished, the temperature is reduced to 475-500 DEG C at the cooling rate of 1-5 DEG C / min, and heat preservation is conducted for 3-5 days at the temperature; and after heat preservation is finished, furnace cooling or quenching cooling is performed to reach the room temperature, and the layered ternary selenide single-phase material with the chemical formula being Ge3Sb4Se7 is obtained. The ternary layered selenide Ge3Sb4Se7 semiconductor material prepared by the invention is a single-phase material and has the characteristics of low thermal conductivity and low resistivity, so that the ternary layered selenide Ge3Sb4Se7 semiconductor material has application potential in the fields of thermoelectric devices, photoelectric detection and the like.

The invention discloses a high-conductivity palladium alloy for a chip test probe and a preparation method of the high-conductivity palladium alloy, and the palladium alloy comprises the following components in percentage by mass: 50-58% of Pd, 35-40% of Cu, 5-10% of Ag, 0.05-1.0% of Cr and 0.1-1.5% of auxiliary elements, the auxiliary element is selected from at least one of Al, Zn, In and Si; the resistivity of the palladium alloy is 8.0 mu omega.cm or below, the Vickers hardness is 450 HV or above, the 90-degree bending frequency is 8 or above, the tensile strength is 1500 MPa or above, and the ductility is 6% or above, the palladium alloy is subjected to pre-smelting and secondary smelting, and at least part of Cu and at least part of Cr in raw materials are mixed and pre-smelted to obtain a copper-chromium intermediate alloy; and the copper-chromium intermediate alloy and the remaining raw materials are mixed and then subjected to secondary smelting. The palladium alloy can meet the urgent requirements of probes in various forms on low resistance, high plasticity and toughness, fatigue resistance, mechanical strength and the like at the same time.

The invention discloses a coal seam working face floor detection and analysis method, and relates to the technical field of detection and analysis. Potential change conditions of different positions and different elevations are observed through a parallel electrical method instrument, resistivity distribution conditions of different depths in a working face and a bottom plate of the working face can be obtained through three-dimensional electrical method inversion, and the resistivity distribution conditions provide technical support for objective and accurate geological interpretation. The hydrogeological condition of the working face floor rock stratum can be better understood, so that an important reference basis is provided for safe mining; the thermal effect and the electromagnetic effect existing in the environment are evaluated and corrected, so that the deviation of the measured conductivity value can be accurately corrected, and the accuracy and the reliability of conductivity measurement data are improved; and inputting the corrected conductivity value SR (xi, yi, zi) of each grid point into a three-dimensional model, and marking to construct a conductivity three-dimensional model, so as to visually display the electrical property distribution information of the underground medium.

The invention relates to the technical field of high-voltage PCB design, and particularly provides a large-model-based high-voltage PCB current path optimization design method and system, and the method comprises the steps: S2, obtaining current distribution according to electrical parameters and layout information through employing an electrical simulation model; s3, acquiring temperature field distribution according to the current distribution, the resistivity of the via hole array and the heat conductivity coefficient of the PCB substrate; s4, acquiring first thermal mechanical stress distribution according to the temperature field distribution, the thermal expansion coefficients of the via hole array and the PCB substrate and the elastic modulus of the via hole array and the PCB substrate; s5, analyzing whether the first thermal mechanical stress distribution meets a preset requirement or not, if yes, taking new layout information as final layout information, and if not, adjusting layout parameters of the via hole array according to the first thermal mechanical stress distribution, and returning to the step S2; according to the method, the problems of local hot spots and thermal mechanical stress caused by uneven current distribution in the high-voltage PCB via hole array can be solved.

The invention discloses a wafer resistivity detection device and method, and relates to the technical field of detection, the wafer resistivity detection device comprises a probe and a measuring instrument, the lower end of the probe is provided with four probes, an adjusting mechanism comprises an accommodating groove formed in the probe, a sleeve is rotatably connected in the accommodating groove, and the probe is arranged in the sleeve. A first connecting rod close to the probe is fixedly connected to the sleeve, a second connecting rod far away from the probe is rotationally connected to the sleeve, swing rods are hinged to the two ends of the first connecting rod and the two ends of the second connecting rod, a supporting rod is hinged to the free end of each swing rod, and the supporting rods are in sliding connection with the probe. The probes are connected with the corresponding supporting rods in a sliding mode, and the conversion mechanism is arranged in the containing groove and used for adjusting the first connecting rod and the second connecting rod to be in a parallel state or a staggered state; the method is suitable for the detection requirement that the distance between the probes needs to be changed frequently, various resistivity measurement requirements are met, and the detection convenience is improved.

The invention relates to the technical field of pretreatment of forming materials, and discloses an automatic proportioning method and device for a conductive grouting tracing material. The technical problem that in the prior art, in the grouting reinforcement process of a foundation pit, the design of the proportion of a conductive tracing material lacks an automatic means, and consequently the electrical resistivity tomography (ERT) effect is poor is solved. The method comprises the following steps: data acquisition and collection; setting parameters and formulating a construction scheme; the grouting ratio is controlled, and construction measures are determined; automatic matching generation and output; and automatic real-time feedback and correction are realized. Through the automatic matching design method, the construction efficiency and the monitoring precision of the foundation pit grouting reinforcement project are remarkably improved, and the necessity of manual intervention and the potential construction risk are reduced. A high-precision sensor and an advanced data analysis tool are combined, dynamic monitoring and intelligent feedback adjustment of the tomography effect in the whole construction process are achieved, and service is provided for engineering quality and construction safety.

According to the preparation method and application of the metal soft magnetic composite material, the surface of the metal soft magnetic powder is coated with the metal oxide insulating layer through the ALD technology, then the characteristics that the ferrite phase layer is high in resistivity, low in loss and good in high-frequency characteristic are utilized, insulating coating is conducted on the surface through the ALD technology, and the metal soft magnetic composite material is obtained. And a ferrite coating layer is formed on the surface of the metal soft magnetic powder during high-temperature annealing, so that electric contact among particles is blocked, the resistivity of the soft magnetic material is improved, and the eddy-current loss at high frequency is reduced, thereby improving the high-frequency performance.

The invention discloses a state evaluation and fault early warning method and system based on superconducting current limiter modeling, an electromagnetic heat multi-physical field coupling model of a superconducting current limiter is constructed based on finite element software, and the method comprises the following steps: constructing a three-dimensional geometric structure of a solenoid-shaped superconducting current limiter, and setting a peripheral electromagnetic environment boundary; establishing an electromagnetic field control equation based on a Maxwell equation set and the nonlinear resistivity characteristic of the superconducting material, and coupling a solid heat transfer control equation to form a multi-physical field interaction model; optimizing grid division to balance calculation precision and solving efficiency; body parameters of the superconducting current limiter including the initial critical current Ic0 and the critical temperature Tc and working condition parameters including the environment temperature and the transmission current It are input, the parameters are dynamically adjusted according to the actual operation scene, and the voltage U at the two ends during normal operation is calculated through a model; by collecting voltage measured values Up at the two ends of the superconducting current limiter during actual operation in real time, whether the voltage measured values Up exceed a threshold value set according to the voltage U or not is judged, and an early warning mechanism is triggered.

The invention relates to an AC-DC integrated grounding fault positioning method and system, and the method comprises the steps: collecting the potential change data of a DC power supply system and the frequency characteristic data of an AC power supply system, and determining the electrical signal characteristics of stray current corrosion; decomposing the electric signal by using wavelet transform, and extracting direct-current and alternating-current components; determining a fault type according to the component amplitude; analyzing the potential gradient and the stray current flow direction in combination with a line topological structure, and determining the position of a fault point; measuring resistance to determine a grounding loop, and analyzing the correlation between corrosion distribution and electrical parameter characteristics; evaluating the influence of corrosion on the grounding path in combination with the material resistivity; according to the method, faults can be accurately recognized, fault points can be accurately positioned, the corrosion degree and the influence of the corrosion degree on the system can be evaluated, and effective support is provided for safe operation and maintenance of a subway power supply system.

The invention discloses composite conductive powder for preparing conductive silver paste and the conductive silver paste, and particularly relates to the technical field of electronic materials.The composite conductive powder is of a double-shell core-shell structure composed of a silver metal inner core, a silicon dioxide middle coating layer and a silver nanoparticle self-assembled outer layer and is subjected to ultraviolet irradiation treatment; the conductive silver paste is based on the composite conductive powder and is matched with cerium oxide modified glass powder, graphene nanosheets, thermoplastic polyurethane resin and a dibasic acid ester solvent to form a low-temperature environment-friendly formula. The volume resistivity of the conductive silver paste is as low as 1.2 * 10 <-6 > omega.cm, the curing temperature is reduced to 120 DEG C, the content of volatile organic compounds meets the environmental protection standard, meanwhile, the tensile strength is improved by 50%, the conductive silver paste can bear 500 times of bending circulation without breakage, the adhesive force reaches the level 0 of a cross-cut method, the strict requirement of a high-performance electronic device for the conductive silver paste is effectively met, and the conductive silver paste has wide application prospects.

The invention relates to the technical field of resistivity method geophysical prospecting detection, and discloses a soil reinforcement effect detection device and method based on electrical resistance tomography. The technical problems that in the prior art, an electrode device is difficult to cover the whole pile body, so that an imaging result has certain limitation, and the electrode device is difficult to adapt to pile bodies of different sizes and shapes are solved. The device comprises a rotary spray irrigation pile, a high-pressure slurry pump and an air compressor, the rotary spray irrigation pile comprises a pipe wall and a grouting pipe, a plurality of electrodes are arranged on the outer side of the pipe wall at intervals, an electrode line channel is arranged on the inner side of the pipe wall, and the electrodes are connected through a wire penetrating through the electrode line channel to form an electrode measurement network. The device has the advantages that the reinforcing process of the rotary spray irrigation pile is monitored in real time, and the physical characteristics of foundation soil or a reinforcing body are accurately analyzed.

An electrophotographic member, comprising: a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member, wherein the conductive layer comprises a matrix comprising a first rubber, and a plurality of domains dispersed in the matrix, volume resistivity of the matrix is 1.00×1012 Ω·cm or less, the plurality of domains comprise at least one domain A, and the domain A satisfies specific conditions, in a case where impedance of the electrophotographic member is measured by applying specific AC voltage while changing frequency in a range of 1.0×10−2 to 1.0×107 Hz and the specific plotting is done, a slope at a specific frequency is −0.80 to −0.30, and the impedance in a specific frequency is 1.00×103 to 1.00×107Ω.

The invention relates to the technical field of logging while drilling, and particularly provides a logging while drilling electromagnetic wave resistivity logging inversion method. The method comprises the following steps: constructing an XGBoost feature screening module, and optimizing a data set through the XGBoost feature screening module to obtain an optimized data set; according to the method, a BiLSTM-Transformer model is constructed, an optimized data set is input into the model, an inversion result is obtained, the inversion precision and the calculation efficiency are improved, and inversion of the target stratum resistivity, the adjacent layer surrounding rock resistivity and the boundary distance under the anisotropic stratum model is achieved.

Provided herein are low resistance metallization stack structures for logic and memory applications and related methods of fabrication. In some embodiments, thin metal oxynitride or metal nitride nucleation layers are deposited followed by deposition of a pure metal conductor. The nucleation layer is amorphous, which templates large pure metal film grain growth and reduced resistivity. Further, certain embodiments of the methods described below convert most or all of the metal oxynitride nucleation layer to a pure metal layer, further lowering the resistivity.

The invention discloses a method and a system for constructing a multi-level geologic structure model based on electromagnetic detection, and the method comprises the steps: transmitting electromagnetic signals with different frequencies at all measurement points through an electromagnetic detector, carrying out the resistivity inversion through apparent resistance and impedance phase, obtaining a geologic electrical structure, dividing non-uniform and uniform electrical geology based on electromagnetic static displacement, and obtaining a multi-level geologic structure model. Analyzing an orthogonal component magnetic field to obtain an electromagnetic response parameter and a polarization ellipse parameter; determining an electric field diffusion curve; obtaining an electric field distribution model through finite difference method inversion; deducing underground geological spatial form and distribution law; and finally, calculating an electromagnetic response curved surface to obtain a two-dimensional profile curve, and performing three-dimensional reconstruction to obtain a multi-level geologic structure model. The method not only can improve the precision and reliability of the structure model, but also has good interpretability, and can be directly applied to a construction system of a multilevel geological structure model based on electromagnetic detection.

The invention provides an electronic wire harness voltage-withstanding performance optimization method, which comprises the following steps: establishing a complete electronic wire harness structure model by analyzing the resistivity and thermal expansion characteristics of a conductor material and combining the performance parameters of an insulating layer, a shielding layer and an outer sheath, and calculating the voltage-withstanding performance of the electronic wire harness by utilizing the technologies of finite element analysis, Monte Carlo simulation and the like. All the components are subjected to collaborative optimization, and accurate control over electric field stress distribution is achieved. Through iterative calculation and parameter adjustment, the overall voltage-withstanding performance of the wire harness can be accurately predicted under the multivariable coupling condition, and a mathematical model of a parameterized voltage-withstanding performance system is generated. The method not only improves the reliability of the electronic wire harness in an extreme environment, but also realizes the real-time evaluation of the voltage withstanding performance, and provides important technical support for the design and application of the electronic wire harness.

The invention discloses a cement-soil pile integrity detection method based on a high-density resistivity method. The method comprises the following steps: recording a background value of a pre-detection depth before construction; drilling holes or arranging in-hole electrodes by using original holes; the resistivity of the pile body after construction is measured by adopting a high-density resistivity method, and impedance inversion is carried out by using inversion software, so that complete resistivity tomography near the pile body is obtained, and the radius of each depth of the pile body is deduced according to the measurement result. The method is advanced and scientific, is simple to implement, conforms to the emerging information technology, can effectively and quickly obtain the continuous and complete depth profile of the pile body including the equivalent pile and the depth, obviously accelerates the measurement speed, greatly reduces the economic cost, obviously improves the measurement precision, and is suitable for popularization and application. The method has high reference value and guiding significance for detecting the diameter of the jet grouting pile.

The invention discloses multi-solvent synergistically activated low-temperature semi-sintered copper paste and a preparation method and application thereof, and belongs to the technical field of conductive paste. The multi-solvent synergistically activated low-temperature semi-sintered copper slurry comprises the following raw material components in percentage by mass: 82-88% of conductive filler, 2-3% of a resin carrier, 4-7% of an activating solvent, 4-7% of a dispersing solvent and 2-3% of a curing agent. Through cooperation of multiple solvents, full-stage activation of the copper particles is achieved, pre-connection and sintering of the copper particles before resin is completely crosslinked and cured are promoted, densification of the overall structure is improved, the insulation barrier effect of the resin is effectively avoided, the resistivity is reduced, meanwhile, inhibition of the resin on sintering of the copper particles is solved, and the service life of the copper particles is prolonged. And good balance between conductivity and interface adhesion is realized. Through resin curing, chemical bonding between the slurry and the substrate can be enhanced, a metal bond network among copper particles is expanded, and mechanical connection stability and electrical performance are guaranteed.

The invention relates to the technical field of lead-acid batteries, and particularly discloses a graphene-based composite material as well as a preparation method and application thereof. The graphene-based composite material comprises a graphene-CNTs three-dimensional composite skeleton, and tin dioxide and titanium dioxide which are loaded on the graphene-CNTs three-dimensional composite skeleton. In the material provided by the invention, the graphene-CNTs three-dimensional composite skeleton has excellent conductivity and mechanical strength, so that the resistivity of a negative plate is remarkably reduced, structural support is provided, and the binding force of lead powder and a negative electrode metal plate grid is enhanced, thereby reducing the falling of active substances and improving the cycling stability of the battery; meanwhile, tin dioxide and titanium dioxide are introduced into the graphene-based composite material and form a multi-stage synergistic system with the graphene-CNTs three-dimensional composite framework, so that the problems that the negative electrode of the lead-acid battery is easy to separate hydrogen, the conductivity is insufficient and active substances fall off can be effectively solved, and the cycle performance of the battery is remarkably improved.

The invention discloses a conductive paste, a metallized substrate and a metallization process for manufacturing the metallized substrate, the conductive paste comprises metal particles, the particle size of the metal particles is 0.1-10 [mu] m, and the mass ratio of the metal particles is 80-98%; in the metallization process, a copper layer is arranged on the hole wall of a through hole or a blind hole of a substrate, then conductive slurry is filled in the hole with the copper layer, heating sintering treatment is carried out, and after heating sintering is carried out in an inert gas atmosphere at the temperature of less than or equal to 300 DEG C, metal particles can be fused to form a connection structure or a eutectic structure. A reinforcing layer can be formed between the nano metal particles and the copper layer, and the reinforcing layer is a metal bonding layer or an intermetallic compound layer. The metallization mode is suitable for a through hole or a blind hole of a glass / silicon / ceramic substrate with a high aspect ratio and a micro aperture, and the technical problems that complete filling is difficult to achieve and filling defects exist in an existing electroplating process, the electrical resistivity of conductive paste is high, and the interface bonding force is insufficient can be solved.

The invention discloses a laser welding method for a copper-aluminum composite material, which comprises the following steps of: performing upsetting thinning treatment on a three-layer sandwich structure base material to ensure that the total thickness of a welding area is 1.5 mm, the thickness of an aluminum layer is 0.9-1.1 mm (the deformation rate is 10-30%), the thickness of a copper layer is 0.2-0.3 mm, the surface roughness Ra is less than or equal to 1.6 mu m, and the surface roughness Ra of an oxide layer is less than or equal to 5 mu m; a 1064nm optical fiber laser is adopted, welding is conducted at the power of 85%-95%, the speed of 120-150 mm / s and the frequency of 4000-6000 Hz, the fusion depth is 0.3-0.6 mm, and the fusion width is 1.2-2.0 mm. By means of the method, the tensile strength of the connector can be larger than or equal to 110 MPa, the resistivity is smaller than or equal to 2.5 * 10 <-8 > omega.m, the problems that traditional welding strength is low and conductivity is poor are solved, batch quality consistency is ensured, and the method is suitable for the fields of new energy automobiles and the like.

The invention discloses a room-temperature-cured high-strength high-thermal-conductivity and high-electric-conductivity silver adhesive which is characterized by comprising the following components in parts by weight: 100 parts of hydroxyl-terminated polydimethylsiloxane, 2-6 parts of carbon nanotubes, 200-450 parts of conductive particles, 1-5 parts of a silane coupling agent, 5-12 parts of a cross-linking agent and 0.5-5 parts of a catalyst. The invention further discloses a preparation method of the room-temperature-curing high-strength high-thermal-conductivity and high-electric-conductivity silver adhesive. The room-temperature-cured high-strength high-thermal-conductivity and high-electrical-conductivity silver adhesive has the advantages of short curing time, low volume resistivity, high bonding strength and good electrical conductivity. The product is tested after being placed in an outdoor environment for 12 months for a long time, the volume resistivity and the bonding strength of the conductive silver adhesive disclosed by the invention are hardly influenced, and the conductive silver adhesive shows excellent weather resistance; the product has high stability and can be used for a long time.

The invention discloses a composite current collector and a forming process method and application thereof. The composite current collector is characterized in that one or more polymer curing layers are formed on a first metal layer through thermal evaporation or coating curing, and second metal layers are formed between the polymer curing layers and / or on the polymer curing layers through evaporation; the forming process method comprises the following steps: forming a polymer curing layer on a first metal layer through thermal evaporation or coating; and repeating thermal evaporation or coating curing and evaporation processes to form a multi-layer stacked structure. The resistivity of the composite current collector is effectively reduced, and the production efficiency of the composite current collector is improved; the metal layer is made of common metal materials in the market, sputtering points do not exist on the metal layer formed through evaporation, the polymer layer is formed through thermal evaporation or coating and then through electron beam or ultraviolet curing, the adhesive force between the metal layer and the polymer layer is effectively improved, and the problems that the electric performance of the composite current collector is reduced, and the service life of the composite current collector is prolonged are solved.

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 discloses a high-thermal-conductivity insulating electric power engineering material and a preparation method thereof, and relates to the technical field of insulating material preparation. The composite material is prepared from 40-60 parts of polyimide resin, 20-30 parts of boron nitride nanosheets, 10-15 parts of alumina micro powder, 5-10 parts of a silane coupling agent, 3-8 parts of a plasticizer, 2-5 parts of an antioxidant, 1-3 parts of carbon nanotube whiskers, 1-2 parts of graphene quantum dots and 0.5-1 part of rare earth yttrium oxide. The diameter-thickness ratio of the boron nitride nanosheet is 100-200, the particle size of the alumina micro powder is 1-5 [mu] m, the diameter of the carbon nanotube whisker is 5-20 nm, the length is 1-5 [mu] m, and the particle size of the graphene quantum dot is 2-10 nm; all the raw materials are synergistically matched, so that the material is expected to have high thermal conductivity and excellent insulating property and is suitable for the field of electric power engineering. The material has high thermal conductivity and excellent insulativity, the thermal conductivity coefficient is not lower than 5 W / (m.K), the volume resistivity is not lower than 1015 omega.cm, and the breakdown field strength is not lower than 30 kV / mm.