409 results about "Surface charges" patented technology

The invention relates to the technical field of water treatment equipment, in particular to an ultrasonic water treatment equipment control method and system based on variable-frequency vibration waves. According to the method, based on preset fluid working condition parameters, ultrasonic frequency conversion vibration wave signals covering multiple frequency bands are dynamically generated, and a vibrator array is driven to generate a composite sound field; a cavitation effect and an activation effect are synchronously excited in a fluid medium through variable-frequency vibration wave signals, so that physical form depolymerization and surface charge distribution change of scale forming substances occur; a shearing effect is formed on a fluid-pipe wall boundary layer, an attached state biological membrane structure is stripped, and the microscopic binding force of a crystallized scale body is loosened; monitoring the dispersion degree of scale-forming substances in the fluid and the state of a boundary layer, and adjusting the frequency band combination and energy distribution of variable-frequency vibration waves to maintain scale inhibition; and continuously optimizing the frequency conversion strategy and the sound field intensity according to the feedback data of the scale inhibition maintenance state. Through intelligent multi-band frequency conversion control of the ultrasonic water treatment equipment, efficient and environment-friendly water treatment and scale prevention effects are realized.

The invention belongs to the technical field of water treatment, and particularly relates to a solar water evaporator and a preparation method and application thereof. According to the solar water evaporator provided by the invention, by using the carbon-based photo-thermal functional materials such as the carbon nanotubes, the micron porous hydrogel and the porous salt-inhibiting mineral powder, an efficient water transmission path and a steam escape path can be provided so as to improve the evaporation efficiency of the solar water evaporator; the porous salt inhibition mineral powder such as diatomite is doped to realize the porous physical salt inhibition mechanism and the surface charge repulsion effect of the mineral powder to effectively inhibit the salt, in addition, through the design of the conical structure with the height-diameter ratio being equal to 1.25, the automatic falling of the surface salt is effectively promoted through the gravity effect, the condition that the salt crystals are difficult to block the pore channels is reduced, and the service life is prolonged. And the evaporation rate stability of the solar water evaporator is improved, so that the technical problem of lack of a high-performance solar water evaporator in the prior art is solved.

The invention provides high-filling silver powder and a preparation method thereof, and belongs to the field of metal powder.The preparation method comprises the steps that a nano-silver solution is prepared, a dispersing agent and a first reducing agent are mixed to obtain a mixed solution, the nano-silver solution and the mixed solution are mixed in a constant-temperature stirring state to obtain a base solution, a second reducing agent solution and a silver nitrate solution are prepared respectively, and the high-filling silver powder is prepared. And under the constant-temperature stirring state, the second reducing agent solution and the silver nitrate solution are synchronously added into the base solution, a silver powder solution is obtained through reaction, the silver powder solution is subjected to washing, solid-liquid separation, drying and depolymerization shaping treatment, and the high-filling silver powder is obtained. Controllable preparation of the large-size sphericity silver powder is achieved by controlling the particle size and the adding amount of the nano-silver, regulating and controlling heterogeneous nucleation and growth sites of silver ions and inhibiting formation of multistage dendritic crystals, surface charges and steric hindrance effects of silver particles are optimized through the surface adsorption effect of the dispersing agent, the agglomeration phenomenon of the silver powder in the growth process is reduced, and the silver powder is prepared. And meanwhile, the silver powder is endowed with excellent flowability.

The invention provides a novel environment-friendly insulating gas surface flashover characteristic evaluation method based on surface charge on-line measurement, which comprises an electric field measurement system based on an electric field induced second harmonic effect (EFISH), a coupling high-voltage surface flashover experiment system, and an evolutionary process of an electric field in a process of applying high voltage to surface flashover, the evolutionary process of charge distribution is obtained based on the electrostatic field source relation, the starting moment of surface flashover is determined by measuring sound, light and electromagnetic signals in the surface flashover process, and the starting area of the surface flashover is observed through a high-speed camera; and associating the relationship between the charge and the surface flashover, and quantitatively explaining the induction effect of the charge on the flashover.

The invention discloses a simulation self-cleaning decorative cloth UV printing ink coating device, and relates to the technical field of printing, the simulation self-cleaning decorative cloth UV printing ink coating device comprises a bearing base, a conveying roller set is fixedly installed at the right end of the upper portion of the top of the bearing base, and through cooperation of a powder particle adsorption assembly, an ink transfer printing assembly and a vibration assembly, the powder particle adsorption assembly and the ink transfer printing assembly are matched; positive and negative charges generated by the positive and negative conductive metal plates cover the peripheral side of the surface of the coating rod, the adsorbability of charge particles on the surface of the printing fabric is improved, a direct-current electromagnetic field is formed outside the coating rod through the feeding motor, the lead screw and the three sets of magnetic rings, and the titanium dioxide is further made to be evenly dispersed in the coating rod under the matching of the mass of the titanium dioxide. The titanium dioxide can be singly captured by charges covering the surface of the fabric to be printed, accumulation of titanium dioxide on the surface of the printed fabric is reduced, and the phenomenon that in the subsequent printing operation process, due to the fact that gaps exist between ink and the printed fabric, ink blocks fall off in the subsequent printing and drying operation is reduced.

The invention discloses a method for preparing micro-nano fibers through needle-free electrostatic spinning equipment assisted by an ion blower gun, and belongs to the technical field of spinning. The method specifically comprises the following steps: S1, dissolving a high-molecular polymer in a proper solvent to prepare a spinning precursor solution; and S2, preparing the micro-nano fiber from the spinning solution on a suitable collection surface by using an ion blower gun assisted needleless electrostatic spinning device. Through the synergistic effect of directional airflow generated by the ion blower gun and a controllable electric field, fiber surface charges are effectively neutralized, the jet instability is inhibited, and the controllability of a fiber flight path is improved. Meanwhile, the ionic wind assists in enhancing interface attachment between the fiber and the collector, uniform deposition is promoted, and the compactness and adhesive force of the fiber membrane are remarkably improved. According to the method, chemical modification does not need to be carried out on a material system, the intrinsic performance of the fiber is kept, universality and expandability are achieved, and a new path is provided for continuous preparation of the high-performance micro-nano fiber.

The invention relates to a neural network-based high-voltage live-line work safety early warning method. The method comprises the following steps of 1, establishing a high-voltage transmission line electric field calculation model by using a surface charge method; 2, establishing an overall three-dimensional model of the transformer substation; 3, constructing a signal processing circuit of the power frequency electric field sensor, capturing electric field information in real time through the power frequency electric field sensor, and converting the electric field information into a processable electric signal; 4, real-time data from the power frequency electric field sensor are received, feature extraction and classification are carried out by adopting an early warning method based on a convolutional neural network, and potential safety hazards are identified; 5, establishing a neural network-based high-voltage live working safety early warning comprehensive platform integrating data acquisition, processing, analysis and early warning; the method has the advantages that the neural network algorithm is adopted, the distance and the azimuth angle are accurately judged, live-line work is early warned, and the accident rate is greatly reduced.

The low-pressure reverse osmosis membrane comprises a non-woven fabric base material, a polysulfone porous supporting layer and a polyamide functional layer. According to the low-pressure reverse osmosis membrane, the non-woven fabric base material is adopted for providing basic support, the polysulfone porous supporting layer has proper thickness and pore diameter, and a stable and transparent supporting structure is established for the polyamide functional layer. Nano titanium dioxide particles are introduced into the polyamide functional layer, and the particle size and the content of the nano titanium dioxide particles and the thickness and the surface carboxyl density of the polyamide functional layer are accurately controlled. Nano titanium dioxide particles are uniformly dispersed in a polyamide network, so that the hydrophilicity and surface charge distribution of a separation layer are effectively improved, and the resistance of water molecules passing through the membrane is reduced, thereby realizing high water flux; meanwhile, the structural stability of the polyamide composite layer is enhanced, and the mechanical strength and pollution resistance of the membrane are improved. Charge distribution and hydrophilicity on the surface of the membrane are adjusted by proper carboxyl density, water molecules are promoted to quickly pass through, solutes such as salt are effectively intercepted, and high desalination rate is realized.

The invention discloses an electrochemical biosensor of a light-driven nanopore channel and application of the electrochemical biosensor. According to the sensor, a photoresponse nanopore membrane is constructed, an outer surface aptamer probe is combined, asymmetric photothermal gradient driven ion transmission induced by near-infrared light is utilized, and ultra-sensitive detection on a target object is realized by regulating and controlling the charge density of the outer surface. According to the electrochemical biosensor provided by the invention, traditional voltage driving is replaced by asymmetric near-infrared light driving, so that the electrochemical biosensor has a relatively wide detection range and an extremely low detection limit, and high-sensitivity and specific detection on a target object can be realized. The electrochemical biosensor can be used for detecting microcystin-LR (MC-LR), the detection limit reaches 1 * 10 <-7 > mu g / L, the sensitivity is improved by 5 orders of magnitude compared with that of a traditional voltage-driven sensor, and the electrochemical biosensor can be applied to trace pollutant detection in the fields of environmental monitoring, food safety and the like.

The invention discloses a three-dimensional bio-based hierarchical pore nanocarbon water photovoltaic power generation material as well as a preparation method and application of the three-dimensional bio-based hierarchical pore nanocarbon water photovoltaic power generation material. The specific technical scheme of the preparation method comprises the following steps: firstly, preparing an acetic acid solution containing chitosan, glucose and borax, and standing the solution at room temperature for 24 hours; then, freeze-drying the precursor solution, and pre-carbonizing xerogel in a drying oven for a certain time; and finally, adding a certain amount of water into the pre-carbonized dry gel, putting the pre-carbonized dry gel into a reaction kettle with a polytetrafluoroethylene lining, reacting for a certain time at a certain temperature, dialyzing the obtained wet gel, and drying at normal temperature and normal pressure to prepare the nano carbon aerogel with the hierarchical pore structure. The nano carbon aerogel has good hydrophilicity, abundant surface charges and a hierarchical pore structure, and is a low-cost and excellent water evaporation induced power generation material.

The present disclosure relates to a process for electrostatic spray drying of a living microorganism with a specific surface charge. using electrostatic charge provided by a high voltage source, wherein said electrostatic charge is the same as the surface charge of the microorganism.

The invention discloses a Janus fog water collecting fiber membrane with asymmetric wettability and surface charge and a preparation method thereof. The material is prepared through an electrostatic spinning technology, and the specific method comprises preparation of hydrophilic and hydrophobic polar polymer spinning solutions and a sequential electrostatic spinning process. Through two-step sequential electrostatic spinning, the Janus fiber membrane with asymmetric wettability and surface charges is directly prepared. The membrane is formed by compounding a hydrophobic fiber layer and a hydrophilic fiber layer, an asymmetric wettability structure is formed, and a directional water transmission function perpendicular to the surface of the membrane can be realized through Laplace pressure difference. In addition, in the high-voltage electrostatic spinning process, surface charges are formed on the surface of the membrane through the polarization effect of the polar polymer, and then the electrostatic adsorption function of fog water is achieved. The prepared material is simple and convenient in process and easy to produce on a large scale, has higher fog water collection efficiency, can be effectively applied to water resource collection in water-deficient areas, and has a wide application prospect.

The invention specifically relates to a multi-parameter state monitoring and fault diagnosis system for an intelligent circuit breaker, and relates to the technical field of state monitoring and fault diagnosis of power equipment. A surface / bulk charge and electroluminescent optical monitoring module; a mechanical-electrical performance correlation analysis module; and a diagnosis evaluation module. According to the invention, the dielectric property micro-change module adopts a low-frequency superposition excitation and partial discharge fingerprint spectrum fusion technology, and can sensitively capture dielectric micro-change of gradual deterioration such as damp and uniform aging; the surface / body charge and electroluminescent module performs mixed optical imaging through a non-contact electrostatic potential array and PMT / APD, and accurately recognizes surface charge accumulation and early electrical tree growth; the mechanical-electrical association module quantifies thermal mechanical stress accumulation and impact vibration influence based on FBG strain monitoring and multi-physics field coupling modeling.

A system for blocking one or more wavelengths, including a window is described, including a detector capable of detecting a target wavelength bandwidth and a first layer connected to the detector. The system includes a second layer that is substantially parallel to the first layer and also connected to the detector. The system includes a plurality of capsules disposed between the first layer and the second layer, and a surface charge-controlled layer in proximity to the first layer or the second layer, connected to the detector and configured to switch one or more of the plurality of capsules from a first state to a second state upon detection of the target wavelength bandwidth.

The invention discloses a plasma / serum low-abundance protein enrichment method. The plasma / serum low-abundance protein enrichment method comprises the following steps: step 1, performing surface modification on nano ferroferric oxide particles by using a surfactant; step 2, enriching low-abundance proteins in the blood plasma; and step 3, detecting and analyzing the enriched protein. According to the method, nano ferroferric oxide is subjected to surface modification by using a surfactant to change the hydrophilic-hydrophobic property and surface charge of the nano ferroferric oxide, and then the nano ferroferric oxide is used for enriching the low-abundance protein of the plasma. According to the method, all raw materials are commercially available, and only simple ultrasonic and oscillation incubation treatment is needed in the modification process, so that the use cost is greatly reduced, and the operation convenience is improved. Compared with an enrichment method for removing abundance protein based on an antibody, the method has the advantages of good enrichment effect, low cost, simple preparation method, compatibility with automatic operation and the like.

The invention provides an aircraft lightning stroke initial attachment point simulation method. The method comprises the steps that connection between first software and second software is established; presetting an initial simulation environment in the first software, calculating a first electrostatic field value of the initial simulation environment and transmitting the first electrostatic field value to the second software; on the basis of the first electrostatic field value, obtaining surface charges through a Gaussian law and judging whether positive polarity pilot is started or not; obtaining the number of negative charges of the positive polarity pilot according to an electrostatic balance principle; obtaining aircraft potential according to the number of negative charges; setting boundary conditions according to the aircraft potential and calculating a second electrostatic field value; and based on the second electrostatic field value, judging whether the negative polarity pilot starts or not through the Gaussian law, and if so, recording the initial position. According to the method, pilot channel charge distribution is converted into potential boundary conditions, and the problem that a traditional method depends on the geometrical shape and the motion state of an aircraft is solved.

The invention discloses a calcium hydroxide and industrial wastewater co-treatment method, and relates to the technical field of environmental engineering, and the method comprises the following steps: S100, adopting global dynamic light scattering and electromotive force imaging combined monitoring, and monitoring surface charge change and particle size evolution of nanoparticles in industrial wastewater in a calcium hydroxide adding process in real time, and extracting a dynamic threshold index of dispersion stability mutation. According to the invention, a dispersion stability threshold is extracted through dynamic light scattering and electromotive force imaging, a particle dispersion risk index is constructed, real-time evaluation of aggregation failure of nanoparticles and dynamic prediction of a feeding strategy are realized, linkage feeding of a chelating organic polyamine flocculant is combined, bridging and surface energy mutation are blocked, and stability of charges and particle sizes is maintained. By means of closed-loop feedback and on-line early warning, the adding proportion is optimized, the gathering and settling efficiency is improved, membrane pollution and filtering blockage are reduced, and the stability and economical efficiency of wastewater treatment are improved.

The invention relates to the technical field of nano materials, and provides a preparation method and application of a friction nano generator with high surface charge density. The invention aims to overcome the defects of low surface charge density, environmental influence, easy aging and the like in high-frequency mechanical energy collection of the existing friction nano-generator, and the application of the friction nano-generator in environmental mechanical energy collection is improved. The main scheme is as follows: 4, the preparation method comprises the following steps: dissolving 4, 4 '-diaminodiphenyl ether in N, N'-dimethylacetamide, adding diphenyl ether dianhydride into the solution to synthesize a polyamide acid solution, carrying out electrospinning and high-temperature treatment on the solution to obtain an imidized nanofiber membrane, treating the surface of the nanofiber membrane through a plasma sputtering instrument, selecting a fluorinated ethylene-propylene copolymer as an electric negative electrode material, and carrying out electrospinning and high-temperature treatment on the surface of the nanofiber membrane. And pasting an electrode and packaging to construct the friction nano generator. The invention is used in the fields of friction power generation, mechanical sensing and the like, and has the advantages of simple process, high preparation speed, high yield, low cost, good robustness, no environmental influence and high output performance.

The utility model belongs to the technical field of high-voltage transmission lines and insulation, and particularly relates to a three-post insulator surface charge measurement experiment device in an electrothermal composite field, which comprises an experiment cavity, a microwave heating system, a charge measurement device and a data acquisition system, the experiment chamber comprises a first experiment chamber and a second experiment chamber, the first experiment chamber is provided with a glass window, a microwave heating system is arranged above the glass window, and the three-post insulator is arranged in the second experiment chamber; a central guide rod embedded in the high-voltage guide rod on the outer side of the first experiment cavity penetrates through the first experiment cavity and penetrates through the three-post insulator, a sliding rail is arranged at the bottom of the second experiment cavity, a charge measuring device is connected to the upper portion of the sliding rail in a sliding mode, and the charge measuring device is connected with a data acquisition system. And the microwave heating system has the characteristics of small thermal inertia and easiness in instantaneous control, automatic control is conveniently realized, and the controllability of the heating process is improved.

The present invention discloses a MOF-derived cobalt trioxide @ cobalt oxide @ cobalt diphosphide composite material and its preparation method and application, which belongs to the technical field of MOF-derived composite materials. It includes: the present invention synthesizes Co‑MOF‑74 by a hydrothermal method, then in-situ oxidation under an air atmosphere, and then in-situ partial phosphating under an argon atmosphere, and the obtained sample is Co3O4@CoO@Co2P composite photocatalyst. The advantage of the present invention is that the composite photocatalyst prepared with rod-shaped Co‑MOF‑74 as a template inherits the regular rod-shaped morphology and porous structure of the MOF precursor, provides more contact and reaction sites for surface charge and mass transfer in the photocatalytic reaction, and promotes the migration and separation of photogenerated carriers. The preparation process of the method of the present invention is simple, the reaction conditions are suitable, it is suitable for large-scale promotion, and has good application prospects in the fields of environment, energy, etc.

The embodiment of the invention discloses a standard substance for simulating biological Zeta potential detection and a preparation method thereof. The method comprises the following steps: (1) preparing a 100-500nm carboxylated nano-microsphere suspension by adopting an emulsion polymerization method; (2) carrying out suction filtration on the 100-500nm carboxylated nano-microsphere suspension through a filter membrane to obtain filtrate; and (3) preparing a phosphate buffer solution with a standard concentration by using the filtrate as a solvent, adding lauryl sodium sulfate, and aging to obtain the standard substance for simulated organism Zeta potential detection. The standard substance provided by the invention can be used for calibrating and verifying a Zeta potential detection instrument, so that the detection accuracy and reliability are improved; meanwhile, the material can be used as an important tool for researching the property and function of surface charges of biomolecules, powerful support is provided for research in the fields of biomedicine and material science, and in addition, the preparation method has the advantages of being simple in process, high in repeatability and capable of simulating Zeta potentials of different biological systems and has a good application prospect.

The application relates to a preparation method of a biosensor. The application relates to a preparation method of a portable pesticide detection biosensor based on acetylcholinesterase (AChE)@poly(allylamine hydrochloride)-hydrogen bond organic framework (PAH-HOF) and application of the biosensor in on-site rapid chlorpyrifos detection, and belongs to the technical field of biosensors. According to the method, AChE is combined with poly(allylamine hydrochloride) (PAH) to change the surface charge and promote self-assembly of the AChE and the hydrogen bond organic framework (HOF), so that an AChE@PAH-HOF composite material with high catalytic activity, high embedding rate and high stability is formed; then the material is integrated into a water-retaining glycerol-sodium alginate hydrogel (G-SA) matrix to construct a disc-shaped sensor. The sensor can be attached to the surface of plants and used for long-term in-situ monitoring of organophosphorus pesticides. In combination with an image processing algorithm, the system realizes accurate tracking of the chlorpyrifos degradation process on the surface of tomato plants, and the detection limit reaches 1 ng / mL. The application provides non-invasive and low-cost technical support for crop health management and sustainable precision agriculture.

Provided is a flocculant for removing heavy metals containing a solvent and nano celluloses dispersed in the solvent. The nano celluloses may have a negative surface charge, and an average length of the nano celluloses may be about 0.2 μm to about 1 μm.

The present invention relates to a MSL membrane with enhanced osmotic energy conversion and a preparation method thereof, belonging to the field of composite material technology. SL is dissolved in water and stirred at room temperature to obtain an SL solution. A MXene nanosheet solution and EGDE are added to the SL solution and mixed. The mixture is stirred under nitrogen, centrifuged, and repeatedly washed until the supernatant reaches neutrality. The precipitate is then redispersed to obtain uniform MSL nanosheets, thereby obtaining a two-dimensional channel MSL membrane. The present invention combines SL, which has abundant functional groups, with MXene, not only addressing the water stability issues of 2D MXene but also providing a larger surface charge for selective ion transport. The ordered MXene skeleton channels provide a shorter permeation path for rapid ion transport, resulting in an MSL membrane with ultra-low resistance.

An organic electroluminescent device (OLED, organic light emitting device) comprising: an anode; a cathode, arranged opposite to the anode; and at least one light emitting layer arranged between the anode and the cathode; wherein the at least one light emitting layer comprises beside at least one emitter EM1 having a surface charge density SCDEM1, a host system comprising at least two host materials, wherein the first host material is a hole-transporting host material h-TMM having a surface charge-density SCDH1 and the second host material is an electron-transporting host material e-TMM having a surface charge-density SCDH2; characterized in that the surface charge-density of the host system SCDhost is > 0.5 mC / m2.

The application discloses an air insulation structure verification method and device based on surface flashover voltage calculation, a terminal equipment and a storage medium, and belongs to the technical field of voltage testing. The method comprises the following steps: obtaining an original structure parameter set; establishing a three-dimensional model according to the original structure parameter set; performing steady-state simulation on the three-dimensional model to obtain an initial electric field distribution; correcting the initial electric field distribution according to surface roughness to obtain a first corrected electric field distribution; performing transient simulation on the three-dimensional model to obtain a surface charge density distribution; correcting the first corrected electric field distribution according to the surface charge density distribution to obtain a second corrected electric field distribution; accumulating the volume with a second corrected electric field value not less than a preset gas critical ionization field strength to obtain a critical volume; and calculating the surface flashover voltage based on the critical volume, and verifying the original insulation structure according to the surface flashover voltage. Therefore, by implementing the application, the problem of inaccurate surface flashover voltage calculation in the prior art can be solved.

The utility model discloses a modification device for producing inorganic non-metal modified powder with good dispersity. The modification device comprises a semi-finished product bin (1), a first spiral reamer (2), an ion fan (3), a medicament barrel (4), a medicament spraying opening (5), a three-roller modification main machine (6), a cyclone separator (7), a pulse cloth bag collector (8), an induced draft fan (9), a recycled powder bin (10), a second spiral reamer (11), a packaging machine (12) and a material drying room (13). According to the device, the three-roller modification host machine is adopted to finish surface modification, so that the modification effect is good; powder modified by the three-roller modification main machine is less in agglomeration and good in dispersing performance after being separated by the air separator; the ion fan ionizes air to generate a large amount of positive and negative charges, so that charges on the surface of the powder during high-speed friction, collision and shearing can be neutralized, and the static electricity removal treatment of the powder is realized; the device can realize continuous production, and is high in yield and low in energy consumption; and the method conforms to green development, and is energy-saving and environment-friendly.

The present invention provides a rodent-proof plastic product, comprising a plastic body layer and a rodent-proof layer disposed on the outer surface of the plastic body layer; the rodent-proof layer is a plastic rodent-proof layer or a paint rodent-proof layer; the rodent-proof layer has a plurality of nanoporous drug carriers; and a rodent repellent is disposed within the nanoporous drug carriers. Nanoporous drug carriers (DDS), which have been widely used in the medical industry for drug infusion into the human body, are now used on plastic products and filled with a rodent repellent. Due to the extremely strong physical adsorption properties (surface charge ‑3.05) and ion exchange properties of the nanoporous drug carriers, the rodent repellent is firmly absorbed, thereby effectively retaining the rodent repellent in the plastic product for a long time without migration or evaporation. When a mouse bites the plastic product, it will escape after biting the rodent repellent and will not bite the plastic product, thereby providing good protection for the plastic product.

The invention relates to the technical field of high-voltage direct-current power transmission equipment, and discloses a direct-current composite insulator umbrella cover with a double-gradient structure, a preparation process and a composite insulator, the umbrella cover is of a three-layer composite structure, and the umbrella cover sequentially comprises a high-resistivity inner layer, a high-dielectric middle layer and a micro-conductive outer layer from inside to outside; the volume resistivity of the high-resistivity inner layer is larger than 1 * 10 < 13 > omega.m, and the thickness of the high-resistivity inner layer is 10%-20% of the total thickness of The volume resistivity of the high-dielectric middle layer is 1 * 10 < 10 >-1 * 10 < 12 > omega.m, the relative dielectric constant is 15-25, and the thickness of the high-dielectric middle layer is 60%-80% of the total thickness of the umbrella cover; the volume resistivity of the micro-conductive outer layer is 1 * 10 < 8 >-1 * 10 < 10 > omega.m, the relative dielectric constant is 5-8, and the thickness is 5%-20% of the total thickness of the umbrella cover. The technical problems that an existing epoxy hard composite insulator umbrella cover is uneven in electric field distribution and surface charges are prone to accumulation can be solved, and automatic regulation and control of the electric field in the insulator body and rapid discharge of the surface charges are achieved.