840 results about "Electric properties" patented technology

The invention relates to the technical field of intelligent manufacturing, in particular to an HTCC ceramic defect automatic identification method based on industrial model assistance, which comprises the following steps: step 1, collecting sintering temperature gradient, lamination pressure and green body water content process parameters in the HTCC production process in real time; step 2, performing non-contact dielectric property scanning on the sintered HTCC substrate on a production line conveyor belt; 3, based on the coordinates of the dielectric abnormal region, controlling an annular polarization light source to inhibit the incident angle reflected by the metallization layer from irradiating the target region; 4, inputting the dielectric anomaly frequency band feature vector and the defect image texture feature in the step 3 into a cross-modal attention network to generate a fusion feature map; and 5, establishing an association mapping library of the defect type and the process deviation type. Through accurate real-time monitoring, intelligent defect identification and classification, automatic process adjustment and a continuously optimized feedback mechanism, the efficiency, quality and intelligent level of the ceramic production process are greatly improved.

The invention belongs to the technical field of dielectric materials, and particularly relates to a dielectric material based on polybenzocyclobutene as well as a preparation method and application of the dielectric material. According to the multi-benzocyclobutene-based dielectric material provided by the invention, different halogenated hydrocarbon, olefin and other raw materials are used, and on the basis of containing more than two benzocyclobutene groups, a specific group can be introduced into a connecting group so as to improve the dielectric property and thermal stability of the material; meanwhile, specific groups can be introduced into R2 and R3 through secondary Heck reaction to further improve the dielectric property and thermal stability of the material, so that the dielectric material with excellent comprehensive properties such as dielectric property and thermal stability is provided, and the technical problem of lack of dielectric materials for high-frequency and high-speed printed circuit boards (PCBs) in the prior art can be solved.

The invention discloses a method and system for testing the electrical performance of a semiconductor chip, and the method comprises the steps: building a mapping relation between dielectric loss and loss frequency through obtaining the dielectric loss data, internal material characteristics and dynamic load power factors of the chip under each frequency band, recognizing a loss abnormal region, and analyzing the influence of the loss abnormal region on the performance of the chip; correcting test data by adopting a minimum mean square error algorithm, and optimizing the impedance of the power supply network and the dynamic switching characteristic of a functional module; calculating the breakdown voltage distribution of each layer in the chip, identifying a high-voltage risk region, optimizing the voltage distribution by using a gradient descent algorithm, and dynamically adjusting the working voltage and current; power factor fluctuation is analyzed through a sliding window algorithm, an abnormal area is identified, a power factor is optimized through a PID algorithm, and the working state and transient response of a chip in a dynamic load are improved. According to the method, the problems of nonlinearity of high-frequency dielectric loss, non-uniform breakdown voltage distribution and unstable power factor response under a dynamic load are solved, and comprehensive and accurate evaluation and optimization of chip performance are realized.

The invention discloses spherical silicon dioxide, a high-frequency high-speed copper-clad plate and a preparation method of the spherical silicon dioxide. The dielectric constant Dk of the spherical silicon dioxide is 3.5 F / m-4. 0F / m, the dielectric loss Df is 0.0001-0.005, the amorphous state proportion is larger than or equal to 99%, the spheroidization rate is larger than or equal to 99%, and the porosity is 0.1%-2%. During preparation, the hydrolysis degree is controlled till partial polycondensation is achieved, then under the oxygen introduction condition, pre-oxidation is conducted at the low temperature to remove alkyl, gradient calcination is conducted at the high temperature, local crystallization influence and defect influence caused by powder spontaneous combustion are prevented, meanwhile, viscous bodies in the microspheres are accurately controlled to flow to fill nanoscale pores, and the particle size is reduced. The spherical silicon dioxide with high purity, high spheroidization rate and low dielectric loss is obtained, the dielectric property of the high-frequency and high-speed copper-clad plate can be met, and the high thermal stability and high reliability of the high-frequency and high-speed copper-clad plate are improved.

The invention discloses a mobile phone data line performance test and fault prediction method and system, and belongs to the technical field of electronic product detection and fault prediction. The power-on resistance, the voltage stability, the charging current response and the data transmission rate of a target data line are collected, and under the conditions of different bending angles, insertion and extraction cycles and environment temperatures, the data transmission rate of the target data line is calculated; acquiring stress response data, and extracting multi-dimensional stress principal component characteristics; the electrical property and stress data are fused, a performance degradation correlation model is established, and coupling modeling of data line internal structure damage and electrical property degradation is achieved; historical use data are input, analogue simulation is carried out through the model, and residual performance indexes are generated; judging whether a fault risk exists or not according to a set threshold value, and outputting early warning information if the fault risk is lower than the threshold value; meanwhile, a fault position and a mode type are inferred in combination with an internal characteristic spectrum of the model; the method has high prediction precision, strong structural adaptability and good expansibility, and is suitable for quality control and intelligent diagnosis of consumer electronic cable products.

The invention discloses an interface covalently bonded core-shell structure boron nitride polypropylene composite dielectric material and a method. The interface covalently bonded core-shell structure boron nitride polypropylene composite dielectric material comprises a maleic anhydride grafted polypropylene matrix and a core-shell structure filler dispersed in the maleic anhydride grafted polypropylene matrix, the core-shell structure filler comprises hydroxylated boron nitride nanoparticles covalently grafted on a polymer shell layer on the surface of the core-shell structure filler; the polymer shell layer is polyglycidyl methacrylate; the epoxy group of the polymer shell layer reacts with the anhydride group of the maleic anhydride grafted polypropylene matrix to form a covalent bond. The invention has the characteristics of strong interface bonding force, uniform filler dispersion, and excellent comprehensive electrical properties and processability.

An additive manufacturing method based on micro-selective laser melting technology. By using a spot size of 30 μm or less, a metal powder layer thickness of 10 μm or less and ultrafine metal powders having a D90 particle size of 30 μm or less, and in combination with the control of a scanning laser power, a scanning rate, a linear energy density and a volumetric energy density within specific ranges, the method can print complex-structured metal parts having extremely high resolutions and surface smoothness, and can obtain a high-density internal structure of a component even under a relatively low energy density or power condition, thereby effectively protecting an optical system. Moreover, a printed component exhibits a defect-free microstructure, and has excellent electrical properties, thermal properties and mechanical properties. Particularly, ultrafine grains and a high dislocation density provide superior mechanical properties compared to conventional manufacturing materials. An infrared laser device can be used, thereby achieving low costs.

The invention relates to a hollow silicon dioxide microsphere and a preparation method and application thereof, the hollow silicon dioxide microsphere has a dielectric constant less than or equal to 2.5, a dielectric loss tangent angle less than or equal to 0.001, a purity greater than 95%, a sphericity rate greater than or equal to 99%, a wall thickness greater than 0 and less than or equal to 0.42 [mu] m, and an average diameter of 0.1 [mu] m-5 [mu] m, and the hollow rate, the wall thickness and the average particle size satisfy a relational expression, eta is the hollow rate, t is the wall thickness, and R is 1 / 2 of the average particle size. The hollow silicon dioxide microspheres provided by the invention are high in spherical rate, firm in wall thickness, uniform in particle size distribution, high in purity, relatively excellent in dielectric property and extremely low in content of metal impurities, and can meet the application requirements of high-speed and high-frequency substrates, in addition, the preparation method provided by the invention is few in adopted raw materials, simple in preparation process, low in cost and high in efficiency.

The invention discloses a lead zirconate titanate film material with an ultrahigh voltage coefficient as well as a preparation method and application of the lead zirconate titanate film material, and belongs to the technical field of electronic material development and film materials. The preparation of the lead zirconate titanate film material is realized by adopting a sol-gel spin-coating method and controlling the annealing times. The piezoelectric film material provided by the invention can be directly deposited on a Si substrate coated with metal Pt, does not need to introduce an additional buffer layer or dope any element, is short in annealing time and simple in preparation process, all required raw materials are cheap and easy to obtain, and the piezoelectric film material particularly has high orientation degree, low coercive voltage and excellent ferroelectric and piezoelectric properties, is suitable for preparing large-size (2-4 inches) wafers, and has a wide application prospect. And huge application potential is shown in the field of piezoelectric micro-electro-mechanical system (MEMS) devices.

The invention belongs to the technical field of energy materials, relates to a thermoelectric material, and particularly provides a high-performance n-type PbS-based medium-entropy thermoelectric material and a preparation method thereof, which are used for solving the problem of poor thermoelectric performance of a PbS-based material in the practical application process of the thermoelectric field. The medium-entropy thermoelectric material PbS (1-x) Sex-yTey is obtained by performing solid solution on a designed amount of Se element and Te element in a PbS-based material, x is more than or equal to 0.48 and less than or equal to 0.5, y is more than or equal to 0.15 and less than or equal to 0.25, and the thermal conductivity of the PbS-based material is effectively reduced; the preparation method comprises the following steps: preparing a medium-entropy thermoelectric material PbS (1-x) Sex-yTey, performing gap doping on the medium-entropy thermoelectric material PbS (1-x) Sex-yTey with a designed amount of Cu element to optimize the carrier concentration, and finally obtaining the high-performance n-type PbS-based medium-entropy thermoelectric material, the room-temperature ZT value and the average ZT value of the material are up to 0.53 and 1.08 respectively, and the material has excellent thermoelectric performance; meanwhile, the high-performance n-type PbS-based medium-entropy thermoelectric material has the obvious advantage of low cost, and wide application of the thermoelectric technology is promoted.

The invention discloses an Ag2Se-based thermoelectric material and a preparation method thereof, and belongs to the technical field of thermoelectric materials. The preparation method comprises the steps that Ag powder and Se powder are mixed and ground according to the molar ratio of (1.9-2.1): 1, and mixed powder is obtained; the mixed powder is subjected to cold pressing to form blocks, and prefabricated blocks are obtained; the prefabricated block is subjected to heat preservation for 20-120 minutes under the conditions that the pressure is 1-5 GPa and the temperature is 400-1000 DEG C, and an Ag2Se initial product is generated through reaction; crushing the primary product, and grinding into fine powder; and sintering the fine powder for 5-30 minutes under the conditions that the pressure is 1-5 GPa and the temperature is 300-900 DEG C, so as to obtain the composite material. The sample is prepared through high temperature and high pressure for the first time, the method is simple, operation is easy to control, the preparation period can be greatly shortened, and the energy utilization rate is increased; the electroacoustic transport performance of Ag2Se is effectively regulated and controlled by changing the pressure and the temperature, and finally the thermoelectric performance is effectively improved.

The invention discloses a method for accurately measuring the dielectric constant of a nonlinear insulating medium, and relates to the technical field of electrical insulation testing. In order to solve the technical defect that in the prior art, a measuring method capable of effectively eliminating the thickness influence and accurately obtaining the real dielectric constant of the nonlinear insulating medium does not exist, the technical scheme provided by the invention comprises the following steps: constructing an equivalent circuit model; collecting dielectric constant measurement values of the samples with different thicknesses, and performing relative dielectric constant testing on the samples with different thicknesses at a plurality of frequency points by using a broadband dielectric spectrometer to obtain data of dielectric constants changing along with the thicknesses; judging whether the dielectric constant has thickness dependence or not; if the thickness dependence exists, the dielectric constant measurement value is substituted into the equivalent circuit model for nonlinear fitting, and the real dielectric constant value of the material is extracted; and outputting a real dielectric constant. The method can be applied to dielectric property accurate measurement and insulation structure design analysis work of nonlinear insulation materials.

The invention discloses a composite positive electrode, a preparation method thereof and an all-solid-state battery. The composite positive electrode comprises a composite solid electrolyte and a positive electrode active material. The composite solid electrolyte comprises a first solid electrolyte and a second solid electrolyte, wherein the molecular structural formula of the first solid electrolyte is Li < 2 + > (4-a) < x > Zr < 1-x > A < x > Cl < 6-by > By; the second solid electrolyte is selected from one or more of sulfide solid electrolytes; the selection of the metal element A and the non-metal element B meets the condition that XIC * x + (1-x) * 1.687 is less than 1.6; and [(6-by) * 3.16 + y * Xp] / [(6-by + y) * (XIC * x + (1-x) * 1.687)] > = 1.9; wherein the valence state of the metal element A is + a, and the valence state of the non-metal element B is-b; xIC represents the electronegativity of the metal element A, and Xp represents the electronegativity of the non-metal element B. According to the invention, the material forming the composite positive electrode is selected based on the electronegativity of the contained elements, so that the stability and the electrical performance are improved.

The invention relates to the technical field of polypropylene compositions and modified polymer materials thereof, and discloses a high-performance polypropylene-based green energy-saving cable insulation layer composition which comprises an isotactic polypropylene matrix, a maleic anhydride grafted polyolefin elastomer distributed in a dispersed phase and an amide nucleating agent distributed on a non-polar phase interface, an anchoring structure is constructed on a phase interface through hydrogen bond interaction, a matrix molecular chain is induced to grow to form a radial needle-shaped crystal cluster penetrating through the phase interface, and a three-dimensional interpenetrating crystal bridging network is constructed. Through the crystal bridging network, interface deep traps are converted into continuous shallow trap diversion channels, charges are guided to migrate orderly, space charge accumulation is inhibited, and the three-dimensional interpenetrating crystal bridging network is constructed. And the steric effect generated by the interface anchoring structure cooperatively restrains the thermal expansion of the dispersed phase, so that the high-temperature dimensional stability and dielectric property of the material are improved.

The invention discloses a power type negative temperature coefficient thermistor and method for suppressing surge current, and relates to the technical field of negative temperature coefficient thermistors, the thermistor comprises a core body and pins, the pins are respectively arranged on electrodes on two sides of the core body by adopting a multi-contact-surface structure, and the pins are arranged on the two sides of the core body. The core body is made of a Mn-Co-Ni-La oxide with a nano composite gradient structure; the Mn-Co-Ni-La oxide with the nano-composite gradient structure determines the upper limits of core capabilities such as surge suppression, wide temperature stability and low power consumption of the thermistor, and the redesign of the pin is the key of performance transfer, so that the electrical properties (low contact resistance and high surge tolerance) of the Mn-Co-Ni-La oxide with the nano-composite gradient structure are not counteracted by structural defects; the arrangement of the bracket prevents the Mn-Co-Ni-La oxide with the nano-composite gradient structure from losing the effect due to heat accumulation and physical damage through thermal management and mechanical protection, and the three components supplement one another and cooperate with one another, so that the performance of the thermistor of the Mn-Co-Ni-La oxide with the nano-composite gradient structure is guaranteed.

The invention provides a compatibilization modified polypropylene capacitor film material with high dielectric property, a preparation method and a capacitor, polypropylene is used as a matrix, ZrO2 with high dielectric constant is used as a nano filler, maleic anhydride grafted polypropylene is used as a compatilizer, and the compatibilization modified polypropylene capacitor film material with high dielectric property is prepared by a method of reducing interfacial force through the compatilizer. The dispersity of the nano zirconium oxide in the matrix is improved, the agglomeration phenomenon of the nano zirconium oxide is reduced, and the nano zirconium oxide is more uniformly dispersed in the matrix, so that the dielectric property of the nano zirconium oxide is improved. The polypropylene-based composite material has the advantages of safety, stability, simplicity in operation, low production cost, good mechanical properties and the like, is suitable for large-scale production, and has a wide application prospect; the thin film capacitor prepared from the material has the advantages in the aspects of current bearing, dielectric loss bearing and the like.

The invention discloses a polyetherimide / polyaryletherketone composite material with high breakdown performance and mechanical toughness as well as a preparation method and application of the polyetherimide / polyaryletherketone composite material, and belongs to the technical field of polyetherimide insulation. The invention solves the problems that the dielectric constant of the polyetherimide can be improved by increasing the use amount of the conductive filler in the prior art, but the breakdown performance of the polyetherimide is reduced, so that the polyetherimide cannot have toughness and high breakdown performance at the same time. According to the invention, polyetherimide and polyaryletherketone are used as raw materials and are mixed by adopting a solution blending method, then a substrate is coated with the mixture, and the polyaryletherketone / polyetherimide / polyaryletherketone composite material is obtained through curing. According to the invention, polyetherimide and polyaryletherketone are well dispersed on a microscopic scale, and the composite material has low dielectric loss of polyetherimide and high toughness of PAEK, and has good dielectric properties and breakdown electrical strength; the material is suitable for the advanced fields of high-energy density capacitors, power electronic devices, aerospace electrical insulation parts, new energy automobile high-voltage systems and the like.

The invention provides a battery pole piece uniformity test method, device and equipment, a medium and a program, and belongs to the technical field of batteries. The testing method comprises the following steps: acquiring a plurality of electrochemical impedance spectrums of a plurality of testing positions of a to-be-tested pole piece based on a pre-constructed locally symmetric battery, the locally symmetric battery being pre-constructed according to the following steps: acquiring the to-be-tested pole piece; an auxiliary test pole piece is obtained, the auxiliary test pole piece and the to-be-tested pole piece are processed through at least one same processing procedure, and the area of the auxiliary test pole piece is smaller than that of the to-be-tested pole piece; and adding a diaphragm between the to-be-tested pole piece and the auxiliary test pole piece to obtain a locally symmetrical battery, determining a plurality of characteristic resistances of the pole piece to be detected according to the plurality of electrochemical impedance spectrums; and determining the uniformity of the to-be-tested pole piece based on the plurality of characteristic resistors of the to-be-tested pole piece. According to the method, the uniformity of the electrical performance of the pole piece can be efficiently evaluated, and a theoretical basis can be provided for process optimization in the battery processing process, positioning of battery failure reasons and the like.

The invention belongs to the field of microwave dielectric ceramic materials, and particularly provides a method for improving the performance of zinc aluminate microwave ceramic based on an LBSCA (Li2O-B2O3-SiO2-CaO-Al2O3) composite sintering aid, so that the prepared zinc aluminate microwave dielectric ceramic material has a low dielectric constant and a high thermal expansion coefficient, and is suitable for manufacturing a ceramic substrate with excellent performance. According to the invention, a Zn < 0.90 > Co < 0.10 > Al < 2 > O < 4 > system is adopted, an LBSCA (Li2O-B2O3-SiO2-CaO-Al2O3) composite sintering aid is introduced, and sintering and dielectric properties are optimized through a plurality of mechanisms. The doping of the LBSCA glass has obvious influence on the microstructure and density of the ceramic, and the microwave dielectric property of the ceramic is further improved. According to the invention, when the sintering temperature is 1175 DEG C and x is equal to 1.5 wt%, the optimal performance is as follows: epsilon r is equal to 5.25, Q * f is equal to 7334 GHz, and tauf is equal to-25.18 ppm / DEG C; the CTE value is the maximum value of 11.18 ppm / DEG C.

The present invention relates to the technical field of aircraft absorbing honeycomb structure damage repair, specifically a method for repairing the electrical properties of damaged absorbing honeycomb cores, comprising the following steps: identifying and marking the outline of the damaged area of ​​the absorbing honeycomb core using nondestructive testing equipment; determining the material system, core cell dimensions, and electrical performance range based on the absorbing honeycomb core structural information; calculating the absorbing honeycomb core skeleton and the absorbing layer duty cycle based on the honeycomb core unit cell margins, wall thickness, and absorbing layer thickness; preparing a new absorbing honeycomb core corresponding to the size of the damaged area of ​​the absorbing honeycomb core, and using a cutting knife to cut along the periphery of the damaged area of ​​the absorbing honeycomb core to remove the damaged absorbing honeycomb core. The present invention selects a small, wave-transparent aramid paper honeycomb core as the skeleton, ensuring consistency with the absorbing honeycomb core material system and facilitating the restoration of mechanical properties. MATLAB mathematical calculation software can be used to calculate the target electrical properties of the adhesive under different small core structural parameters, enhancing the designability of the repair solution.

A composite current collector, including a metal substrate layer and a functional layer located on a surface of the metal substrate layer; where the functional layer is analyzed using an energy dispersive spectrometer, and based on a total number of atoms of the C element, the O element, and a metal element in the functional layer, an atomic percentage of the C element in the functional layer is x, an atomic percentage of the O element in the functional layer is y, and an atomic percentage of the metal element in the functional layer is z, satisfying: 5%≤x≤25%, 10%≤y≤30%, and 55%≤z≤85%. The functional layer with specific element contents on the surface of the metal substrate layer, a coverage of a coating on a surface of the composite current collector can be effectively improved while electrical performance is ensured, thereby improving the safety of the electrochemical device.

The embodiment of the invention provides an insulating film and a preparation method thereof, an insulating composite film and a preparation method thereof, and electrical equipment, and relates to the technical field of expansion materials. The insulating film comprises a fiber matrix and an expansion compound, and the expansion compound is compounded in the fiber matrix. The insulating film can be prevented from being separated or cracked, and the electrical property and the mechanical property of the insulating film are improved.

The invention relates to the technical field of battery research, development and detection, in particular to a ternary lithium ion battery electrode material electrical performance test device, which comprises a box body and a lithium battery body, the top of the box body is not closed, and the outer walls of the two sides of the box body are symmetrically and slidably connected with U-shaped lifting plates respectively; a mounting plate is fixedly connected among the bottom ends of the four U-shaped lifting plates, the mounting plate is located in the box body, and an annular shell is fixedly connected to the position, close to the middle, of the top of the mounting plate. The mounting plate and the lithium battery body integrally descend into the box body, and meanwhile, the top of the box body is closed by the two top covers, so that the deflagration lithium battery body is sealed in the box body, and the problems that fire possibly spreads quickly, irreversible damage is caused to test equipment, and the test efficiency is high are effectively solved. And the life safety of workers can be seriously threatened.

The invention relates to the field of composite conductive fibers, and discloses a composite conductive fiber quality detection system, which is characterized in that serial number identification and appearance contour extraction are carried out on composite conductive fibers entering a detection area by combining an image identification algorithm with an optical imaging technology; performing electrical property parameter acquisition on the composite conductive fiber by using a non-contact electrical property sensor, and correcting detection data in combination with a temperature compensation algorithm; based on the multispectral imaging and microstructure modeling technology, the integrity and uniformity of the internal and surface structures of the fibers and the adhesion state of a metal layer are analyzed; performing feature fusion analysis on the acquired electrical performance parameters by using a machine learning model, classifying and identifying typical defects, performing grade evaluation on the severity of the typical defects, judging whether the evaluation grade is a high-grade defect, and if so, entering a feedback calibration module; and a targeted regulation and control instruction is automatically generated in combination with a detection result and historical quality data of the production line. The method has the advantage of improving the detection efficiency.

The invention relates to the technical field of low-dielectric-loss materials, in particular to a high-performance soluble polytetrafluoroethylene material and a preparation method thereof. The high-performance soluble polytetrafluoroethylene material is prepared from the following raw materials in parts by mass: 85 to 100 parts of soluble polytetrafluoroethylene resin, 3 to 7 parts of nano silicon dioxide, 3 to 7 parts of boron nitride or activated boron nitride, 2 to 4 parts of aluminum oxide, 1 to 3 parts of strontium titanate and 0.1 to 1 part of coupling agent. Compared with a traditional low-dielectric-loss material, the low-dielectric-loss low-dielectric-loss material has the advantages that the low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss low-dielectric-loss

The invention provides a low-dielectric-constant material dielectric property prediction method and system based on machine learning, and the method comprises the steps: obtaining material data, and carrying out the preprocessing to obtain basic attributes; performing feature engineering to obtain a feature matrix; dividing the feature matrix into a data set and processing the data set; training the model to obtain an optimal model; and evaluating the optimal model, and serializing and storing the optimal model. The structure of a machine learning method combining specific feature engineering, training data noise enhancement, a sample weighting strategy and a random forest model solves the problem that an existing machine learning model accurately predicts a specific low dielectric constant (lt; and 5) the problems that the precision in the aspect of materials is insufficient and the efficiency of a traditional material screening method is low are solved, and the efficiency and accuracy of discovery of the low-dielectric-constant new materials and the robustness and generalization ability of prediction are improved.

The invention belongs to the technical field of batteries, and particularly relates to iron phosphate dehydrate and a preparation method and application thereof.The phase of the iron phosphate dehydrate comprises a monoclinic phase and an orthorhombic phase, characteristic peaks of the iron phosphate dehydrate at the 2theta ranging from 17.6 degrees to 18.3 degrees are in double-peak distribution according to XRD testing, the double peaks comprise a single peak A at the 2theta ranging from 17.8 degrees to 18.0 degrees and a single peak B at the 2theta ranging from 18.0 degrees to 18.3 degrees, and the characteristic peaks of the iron phosphate dehydrate at the 2theta ranging from 17.6 degrees to 18.3 degrees are in double-peak distribution. And the half-peak width ratio of the single peak A to the single peak B is 0.90-0.97. When the iron phosphate dehydrate with the specific crystal structure is used for preparing iron phosphate and lithium iron phosphate materials, the compaction density and the electrical performance of the final lithium iron phosphate material are remarkably improved.

The invention belongs to the technical field of electronic circuit integration, and particularly relates to an intelligent control multilayer circuit board. Comprising a multi-layer composite structure, and the multi-layer composite structure comprises a first signal layer, a second signal layer, a third signal layer and a fourth signal layer which are sequentially stacked from top to bottom, a first dielectric layer disposed under the first signal layer; the second signal layer is arranged below the first dielectric layer, is a copper layer with the thickness of 2 microns and is used for transmitting intermediate frequency signals; the intelligent dielectric layer is arranged below the second signal layer; the third signal layer is arranged below the intelligent dielectric layer; a second dielectric layer; a fourth signal layer disposed under the second dielectric layer; the substrate layer is arranged below the fourth signal layer, and the surface of the substrate layer is provided with a bionic cobweb supporting structure; and the dielectric constants of the multilayer circuit board are in gradient distribution along the thickness direction. According to the invention, the real-time dynamic adjustment of the dielectric property of the circuit board is realized, the electromagnetic property can be optimized according to different working frequencies or signal requirements, and the signal transmission quality in a high-frequency / high-speed scene is remarkably improved.

The invention discloses a reverse molecular design method and system of an organic framework material COFs based on a machine learning and quantitative calculation technology, and relates to the technical field of material science and computer simulation. The photoelectric property of the COFs material can be accurately predicted, and a new material can be directionally synthesized under guidance. A COFs structure database is established, Gaussian is used for representing the fragment structure and electronic characteristics of the COFs, a molecular descriptor and a machine learning algorithm are used for establishing a structure-performance mapping relation, quantitative calculation software is used for obtaining an important target quantity for describing the photoelectric characteristics of the COFs, SHAP is used for carrying out importance analysis, and finally a machine learning model for predicting the photoelectric properties of the COFs is obtained. According to the model, through theoretical prediction of a novel COFs structure, a mapping relation between the COFs structure and photoelectric specificity can be established, and a novel COFs hypothetical structure can be reset according to important molecular fragments or word structures of the important molecular fragments; theoretical guidance can be provided for application in the fields of photoelectric catalysts and the like.

The present invention belongs to the technical field of microwave-absorbing materials, and specifically relates to a method for preparing a cobalt / attapulgite / carbon nanocomposite fiber with microwave-absorbing properties. The preparation method comprises the following steps: mixing a magnetic metal salt, a polymer, a solvent, and nano-attapulgite in a specific proportion, reacting under heating conditions and at room temperature to obtain a mixed spinning solution; electrospinning the mixed spinning solution to obtain composite nanofibers; and carbonizing the obtained composite nanofibers to obtain a cobalt / attapulgite / carbon nanocomposite fiber with microwave-absorbing properties. The present invention has the beneficial effect that, due to the adoption of the above-mentioned technical solution, the carbon nanocomposite fiber of the present invention combines excellent properties such as light weight, strong absorption, a wide effective absorption bandwidth, and a low filling ratio. The carbon nanofibers have excellent dielectric properties, electrical conductivity, thermal stability, and low density. Carbon nanofibers are expected to be used to produce ideal microwave-absorbing materials.