30results about How to "Increase density" patented technology

The invention discloses a laser-TIG (Tungsten Inert Gas) hybrid welding and method based on ultrasonic-assisted wire powder coaxial conveying, after entering, a laser beam forms a semicircular Bessel beam through a lens, a metal wire passes through an ultrasonic-assisted device and then introduces vibration into a welding pool, and six powder conveying guide pipes are uniformly distributed around the metal wire; according to the wire core six-way powder channel coaxial device, a semi-circular light beam passes through the wire core six-way powder channel coaxial device and enters a laser head, and finally the effect of coaxially melting a wire powder material through laser is achieved. A TIG welding auxiliary device is added to one side of a molten pool, metallurgical reaction is promoted, and compactness of a welding seam is improved. The device mainly comprises an annular laser beam wire core six-way powder channel simultaneous melting system, an automatic wire feeding system, a powder feeding system, an ultrasonic vibration system, a TIG auxiliary welding system and the like. The welding efficiency can be improved through the wire core six-way powder channel coaxial melting technology, the flowing stability of a molten pool can be promoted through the ultrasonic-assisted technology, and the welding seam forming quality can be improved through laser-TIG composite welding.

The invention relates to a stirring friction extrusion solid phase additive deposition layer edge precision control device and method, and belongs to the technical field of additive manufacturing, the stirring friction extrusion solid phase additive deposition layer edge precision control device comprises a hollow stirring head, the hollow stirring head can rotate, and a through hole is formed in the central axis of the hollow stirring head and used for filling raw materials; the periphery of the hollow stirring head is sleeved with four split type sleeves, and the four split type sleeves can independently move up and down respectively. According to the method, side wall forming of the additive layer is limited, generation of burrs, the arc-shaped side wall and semi-cylindrical materials at the two ends of the additive layer is restrained, and therefore the follow-up cutting amount is reduced, and near-net forming of components is achieved; by limiting the plasticized material to flow to the periphery, the additive layers at the center and the edge are more compact, and the mechanical properties of the whole additive layers and the side wall part are improved; and multi-layer material adding in the vertical plane and multi-channel material adding in the horizontal plane can be achieved, accurate forming of the side wall can be achieved under the condition that the device is not replaced, and the flexibility of the device is improved.

The present invention relates to a device and method for controlling the edge precision of a stir friction extrusion solid-phase additive deposition layer, which belongs to the field of additive manufacturing technology, and includes a hollow stirring head, which can rotate, and a through hole is arranged at the central axis thereof for filling raw materials; four split sleeves are sleeved around the hollow stirring head, and the four split sleeves can move up and down independently. The present invention restricts the side wall forming of the additive layer, suppresses the generation of flash, arc-shaped side walls and semi-cylindrical materials at both ends of the additive layer, thereby reducing the subsequent cutting amount and achieving near-net forming of the component; by restricting the flow of plasticized material to the surroundings, the additive layer at the center and the edge is made denser, and the mechanical properties of the additive layer as a whole and the side wall are improved; it can realize multi-layer additives in the vertical plane and multi-pass additives in the horizontal plane, and can also realize precise forming of the side wall without changing the device, thereby improving the flexibility of the device.

The invention provides a strong acid-resistant ionic waterborne epoxy curing agent as well as a preparation method and application thereof, and belongs to the technical field of epoxy coatings. The waterborne epoxy curing agent is prepared from the following raw materials in parts by mass: 10 to 20 parts of taurine, 20 to 35 parts of amine, 65 to 70 parts of binary epoxy resin, 6 to 12 parts of monoglycidyl ether compound, 35 to 40 parts of organic solvent and 80 to 95 parts of water. The binary epoxy resin comprises a diglycidyl ether compound and epoxy resin with double epoxy groups. The preparation method comprises the following steps: neutralizing taurine by amine to obtain hydrophilic ammonium salt, dropwise adding binary epoxy resin to carry out chain extension on amine and taurine, and finally sealing redundant primary amine in a system by using a monoglycidyl ether compound to obtain the strong acid-resistant ionic waterborne epoxy curing agent. The obtained strong-acid-resistant ionic waterborne epoxy curing agent has hydrophilicity, a paint film formed by mixing and curing the strong-acid-resistant ionic waterborne epoxy curing agent and epoxy emulsion has excellent adhesive force and corrosion resistance, and the preparation cost is low.

The invention discloses ultrahigh-plasticity hot-rolled austenitic stainless steel and a preparation method thereof, and belongs to the technical field of austenitic stainless steel production and manufacturing. The preparation method comprises the following steps: smelting and pouring according to a certain mass percent of chemical components to obtain a steel billet, homogenizing the steel billet, and forging the steel billet into a square billet; performing multi-pass hot rolling on the square billet to obtain a hot-rolled plate, performing interrupted solution treatment on the hot-rolled plate, and performing water cooling to room temperature; by controlling element selection of C, Cr, Mn, Ni and N and cooperating with a multi-pass hot rolling-solid solution interruption preparation method, an austenite structure after complete recrystallization is regulated and controlled firstly, then part of austenite is recrystallized again through low-temperature solid solution, and high mechanical stability and excellent strong plasticity are obtained based on two recrystallization behaviors.

The invention discloses a seawater electrolyzed water hydrogen production and energy cascade storage and utilization system which comprises an offshore steel frame platform. A seawater pump, a seawater purification device, a purified water storage tank, a water pump, an alkaline water electrolytic bath, a hydrogen purification and impurity removal device, a hydrogen storage tank, a hydrogen flow controller, a pyrolysis device, a gas purification and impurity removal device, a gaseous carbon dioxide storage tank, a carbon dioxide flow controller and a compressed carbon dioxide energy storage and heat exchange system are arranged on the offshore steel frame platform; the liquid carbon dioxide storage tank is arranged in the seabed below the offshore steel frame platform and connected with the compressed carbon dioxide energy storage and heat exchange system. Offshore wind power, photovoltaic energy and temperature difference energy are utilized for power generation, biomass is adopted for preparing seawater desalination wood and generating carbon dioxide, seawater is electrolyzed into hydrogen, the hydrogen and the carbon dioxide are synthesized and converted into green liquid fuel, and oxygen is used for supplying oxygen to an underwater system.

The invention discloses a modified multi-walled carbon nanotube, a flame-retardant PET (Polyethylene Terephthalate) material and a preparation method of the flame-retardant PET material. The preparation method of the modified multi-walled carbon nanotube comprises the following steps: S1, mixing a multi-walled carbon nanotube with mixed acid, carrying out ultrasonic oscillation for 15-25 minutes, refluxing for 1-2 hours, diluting with distilled water, filtering, and washing with water until filtrate is neutral; and S2, mixing the product in the step S1 with the mixed solution, refluxing for 1-2 hours, diluting with distilled water, filtering, washing with water until the filtrate is neutral, and drying the filter cake to obtain the modified multi-walled carbon nanotube. According to the prepared modified multi-walled carbon nanotube, the surface carboxyl grafting rate is greatly increased while the structure is maintained. When the flame retardant is applied to a flame-retardant PET material, the flame retardant property and the mechanical property of the PET material can be remarkably improved.

The invention relates to the technical field of secondary batteries, in particular to conductive paste and a preparation method thereof, and a carbon-coated current collector and a preparation method and application thereof, and aims to solve the problems that a carbon-coated layer in the prior art is poor in adhesive force and easy to peel off, and conductivity is reduced by increasing an adhesive in order to improve the adhesive force; the conductive material in the carbon-coated layer is poor in dispersity and easy to agglomerate, and the carbon-coated layer is thick. A carbon-coated current collector comprises a current collector body and a carbon-coated layer covering at least one side of the current collector body along the thickness direction of the current collector body, the carbon-coated layer comprises the following components: graphene oxide, modified graphene, modified carbon nanotubes, conductive carbon black and a binder in a mass ratio of (1-10): (10-45): (1-20): (1-10): (1-5), both the modified graphene and the modified carbon nanotubes contain oxygen-containing groups.

This invention discloses an acid and alkali resistant polyamide membrane and its preparation method. The method is as follows: S1: Immerse the ultrafiltration base membrane in an aqueous sodium hydroxide solution for soaking and then set aside; S2: Treat the base membrane with a mixed aqueous solution of polyamine and aziridine crosslinking agent; S3: Wet the base membrane in an organic phase solution of polyacrylamide monomer to obtain a polyamide composite membrane; S4: Immerse the prepared polyamide composite membrane in an alcoholic solution of hydroxymethyl crosslinking agent, then dry it in a forced-air drying oven, and after washing with water, obtain the acid and alkali resistant polyamide membrane. This application uses two crosslinking agents, aziridine and hydroxymethyl, which can undergo specific crosslinking reactions with the carboxyl groups inside the polyamide membrane, to directly perform dual crosslinking modification on the membrane interior and surface, without introducing other polymer materials to avoid excessive increase in membrane permeation resistance. The polyamide membrane prepared by this method has both good acid and alkali resistance and water permeability.

The invention discloses an air pollution traceability analysis method. The method comprises the following steps: acquiring actually measured meteorological data of monitoring points in a target area; meteorological scene data matched with the actually measured meteorological data are determined according to a meteorological scene library, and the meteorological scene library comprises various kinds of meteorological scene data; pollution traceability data matched with the meteorological scene data are determined according to a pollution traceability library, and the pollution traceability library comprises multiple kinds of pollution traceability data in one-to-one correspondence with the multiple kinds of meteorological scene data; and determining an emission source of the matched pollution traceability data and a concentration contribution value corresponding to the emission source according to the CALPUFF mode. The method is suitable for industrial parks with high density, numerous emission sources and complex pollutant components, the specific pollution characteristics of a certain emission source in the industrial parks and the concentration contribution value of pollutants can be accurately measured, and accurate, efficient and reliable traceability is achieved. The invention further discloses a computer storage medium and a computer program product.

This aluminum powder mixture is obtained by mixing a starting material powder, which is composed of pure aluminum or an aluminum alloy, with 5% by mass to 30% by mass of an aluminum alloy powder that has a lower melting point than the pure aluminum or the aluminum alloy. The aluminum alloy powder is composed of an aluminum alloy which has a composition that contains 5% by mass to 20% by mass of at least one of Si and Cu, and 0.2% by mass to 2.0% by mass of Mg, with a balance of aluminum and unavoidable impurities. Consequently, sintering among the aluminum powders is accelerated and it is possible to obtain an aluminum sintered body that has a higher density and a high electrical conductivity as well as obtaining a high thermal conductivity.

The application provides a method for reducing thermal damage of a cooling medium and a laser processing array. The method can reduce or even avoid the formation of a thermal damage area of the laser processing, improve the processing quality, and particularly can improve the density of an array structure, and obtain a ceramic product containing a high-integration array structure.

The present invention discloses an MPP cable protection tube with strong Vicat performance and a preparation method thereof, wherein the material of the MPP cable protection tube with strong Vicat performance comprises modified polypropylene, modified calcium sulfate whisker, antioxidant and filler; the modified polypropylene is prepared by reacting a heat-resistant silane coupling agent with copolymerized polypropylene; the heat-resistant silane coupling agent has a structure as shown in the following formula A. The MPP cable protection tube with strong Vicat performance provided by the present invention is based on the excellent high temperature resistance of the modified polypropylene prepared by reacting the heat-resistant silane coupling agent with copolymerized polypropylene and doping with modified calcium sulfate whisker, which can not only make the prepared MPP cable protection tube have excellent Vicat performance, but also have excellent compatibility and bonding stability between the components, which can further improve the Vicat performance of the MPP cable protection tube, so that it can be widely used in the field of cable protection tubes.

The invention relates to a flame-retardant weather-resistant thermoplastic elastomer and a preparation method thereof, and belongs to the technical field of flame-retardant material preparation, and the preparation method specifically comprises the following preparation steps: S1, collecting a lignin raw material, crushing, sieving, and sequentially carrying out enzymolysis treatment and acidolysis treatment on the lignin raw material to obtain pretreated lignin; and S2, mixing the pretreated lignin, polyester polyol, a chain extender and a flame retardant, uniformly stirring, adding isocyanate, raising the temperature of a system, reacting for 2-3 hours, transferring the system into a mold, and balancing at room temperature to obtain the flame-retardant weather-resistant thermoplastic elastomer. The prepared elastomer has the characteristics of good weather resistance, good flame retardant effect, simple preparation and no pollution.

The invention discloses a super wear-resistant high-hardness nano titanium ceramic coating and a preparation method thereof, and relates to the technical field of coatings. The present invention first uses 4-hydroxycrotonic acid and phosphorus pentoxide to modify epoxy resin, and then reacts with a silicone resin matrix to improve the peeling resistance of the coating; then the silicone resin matrix is ​​further modified with n-propanol to improve the peeling resistance of the coating, and has good compatibility with a homemade coating; then the acidified carbon nanotubes are used to adsorb cerium ions, precipitate to form a layered hydroxide, and then butyl titanate is intercalated therein, and after two heatings, titanium porcelain is formed to obtain a homemade filler, which is a three-dimensional composite structure, can be arranged in an overlapping manner in a resin matrix, improves the wear resistance of the coating, and then is treated with ion nitriding to effectively improve the wear resistance of the coating. The coating prepared by the present invention has the effects of wear resistance and peeling resistance.

The utility model relates to the field of rock drilling equipment, in particular to a cutting head of a heading machine. Comprising a cutting head body, the cutting head body is a circular truncated cone, and a plurality of tooth holders are arranged on the cutting head body; the cutting teeth are arranged on the tooth holders, the multiple tooth holders are sequentially arranged along the peripheral wall of the cutting head body in the shape of a spiral line, and the lead angle of the spiral line is increased from the bottom end of the cutting head body to the top end of the cutting head body; the spiral line comprises a plurality of spiral line sections which are sequentially connected from the bottom end to the top end of the cutting head body. The cutting head provided by the utility model can be used for slotting operation of an underground closed groove by the existing equipment, the circular truncated cone can meet the shape requirement of the closed groove, and the cutting teeth are arranged in a manner of increasing the lead angle from the bottom to the top of the cutting head body, so that the axial distance of the cutting teeth at the top of the cutting head is properly increased; and the pick density at the top of the cutting head is effectively improved.

A strain of northern cold-region Morchella WZ-23 and a cultivation method of its fruiting body, the present invention relates to a strain of northern cold-region Morchella WZ-23 and a cultivation method of its fruiting body. The purpose of the present invention is to solve the problem of low yield of existing Morchella under low temperature conditions. The present invention is a strain of northern cold-region Morchella WZ-23, which is Morchella eohespera WZ-23 from three places, preserved in the China Center for Type Culture Collection, the preservation address is Wuhan University, Wuhan, China, the preservation date is December 5, 2023, and the preservation number is CCTCC NO: M 20232465. The strain screened by the present invention solves the problem of unstable yield and traits in the northern cold region because the main cultivated varieties are southern varieties. The present invention is applied to the field of edible fungi.

The present invention discloses a paper-plastic integral cylindrical bottle compacting mechanism with radial telescopic function, which is composed of a bottle body pressing plate driving mechanism, a bottle bottom pressing plate driving mechanism, a bottle body pressing plate, and a bottle bottom pressing plate. The bottle body pressing plate driving mechanism comprises: a central shaft, a sliding sleeve, a hinge seat C, a connecting rod A, a connecting rod B, and a connecting rod G connected to each other; the bottle bottom pressing plate driving mechanism is composed of a connecting rod E, a central connecting rod, a bottle bottom driving rod, and a hinge seat D. The present invention can improve the density of paper fibers in the bottle body of the paper-plastic integral cylindrical bottle and improve the strength of the bottle body structure.

The invention relates to a porefilling silver electrode slurry and a preparation method thereof. The invention relates to a pore-filling silver electrode paste, which comprises 85%-90% of silver powder, an organic carrier, 0.1%-0.5% of isophorone, 0.1%-0.5% of diacetone alcohol and 0.1%-1% of polyamide wax, the silver powder comprises silver micro powder and submicron silver powder, and the ratio of the silver micro powder to the submicron silver powder is (8-10): 1; the particle size of the silver micro powder is 1.5-2.5 microns, and the tap density is greater than 6.5 g / ml; the particle size of the submicron silver powder is 0.3-0.6 mu m, and the tap density is larger than 5.5 g / ml. The preparation method comprises the following steps: uniformly mixing the raw materials, and grinding to below 6.0 microns to obtain the pore-filled silver electrode paste. The slurry provided by the invention does not need to be doped with various metal and non-metal materials, is simple in process technology, can effectively improve the conductivity of a communication point electrode, ensures that the communication point is well connected with an internal silver electrode, and remarkably improves the product quality.

This invention discloses a brewing method for "Lanzhongyin" craft beer, possessing a unique flavor, belonging to the field of beer brewing technology. This method uses water, Australian barley malt, Australian wheat malt, and oat flakes as base ingredients, combined with liquid yeast and imported hops. It emphasizes the addition of bitter orange peel and coriander seeds as flavor modifiers. Through optimized processes such as saccharification, boiling, fermentation, and aging, the refreshing fruity aroma of bitter orange peel and the unique spiciness of coriander seeds are deeply integrated, solving the technical problems of existing craft beers having a single flavor profile and insufficient complexity. The "Lanzhongyin" craft beer brewed by this invention has a refreshing and smooth taste, combining the richness of malt, the delicate aroma of hops, and the unique complex flavor brought by bitter orange peel and coriander seeds. It has high flavor recognition, a simple and controllable process, is suitable for large-scale production, and enhances the product's market competitiveness.

The application relates to a point cloud processing method and device. The method comprises the following steps: determining a first transformation matrix corresponding to adjacent first and second point cloud frames through a particle swarm optimization algorithm; rotating and / or translating an original coordinate system of the first point cloud frame through the first transformation matrix to obtain a first coordinate system corresponding to the first point cloud frame; and superimposing first point clouds in the first point cloud frame into the second point cloud frame according to the first coordinate system, a driving speed of a device, and a time difference between the first and second point cloud frames. The scheme provided by the application can increase the density of point clouds and improve the recognition ability of a laser radar for long-distance obstacles.

The application discloses a shell reinforcing method of lithium residue-based non-burning light aggregate and the lithium residue-based non-burning light aggregate after shell reinforcing. The shell reinforcing method comprises the following steps: S1, mixing lithium smelting residue, solid waste and auxiliary materials to obtain mixed materials; S2, performing initial granulation treatment on the mixed materials to obtain green balls; S3, performing round-pot granulation treatment on the green balls to obtain shell reinforced green balls; and S4, performing curing treatment on the shell reinforced green balls to obtain the lithium residue-based non-burning light aggregate. According to the shell reinforcing method, after the green balls are obtained through initial granulation, the round-pot granulation treatment is performed, the special granulation mode is used, the outer shell of the lithium residue-based non-burning light aggregate is mechanically reinforced, the compactness of the surface of the lithium residue-based non-burning light aggregate is improved under the condition of ensuring the same bulk density, and thus the cylinder pressure strength is improved and the water absorption rate is reduced.

The utility model discloses a compact-structure dense feeding device for cup-shaped objects, which belongs to the technical field of cup-shaped object manufacture and comprises a first cup holder bedplate, and a cup holder blanking unit is mounted on the first cup holder bedplate. The cup holder blanking unit comprises a driving device and a blanking device, the first cup holder table plate is connected with the blanking device, the blanking device is connected with the driving device, and the driving device is connected with the support assembly; a support assembly used for supporting is installed on the first cup holder table plate and connected with a driving device. A measuring device used for monitoring is installed on the support assembly. Compared with the prior art, only one cup stand is placed at a time, the situation that multiple cup stands cannot be subjected to subsequent machining after being stacked is avoided, meanwhile, the distance between the feeding devices is shortened through the transmission mode of the belt wheels, the device is more compact in structure through the alternately-placed blanking guide barrels, the feeding dense degree is improved, and the feeding efficiency is improved. And the productivity efficiency is improved, and all the feeding devices are relatively independent and convenient to maintain.

The invention provides a 3D printing concrete material containing a composite filler and a preparation method of the 3D printing concrete material. The 3D printing concrete material is prepared from the following components: a cementing material, fine aggregate, coarse aggregate, a water reducing agent, the composite filler and water, the composite filler is prepared by adopting a method comprising the following steps: (1) uniformly stirring water-absorbent resin, polyacrylamide and cellulose ether; (2) putting the composite filler precursor obtained in the step (1) into water, adding flaky clay, fully stirring, and drying into powder; and (3) adding the composite filler intermediate obtained in the step (2) into a water-based polymer monomer and a curing agent, and uniformly stirring. The 3D printing concrete material containing the composite filler can automatically fill the internal defects caused by a printing process in a printing forming stage, the internal microstructure compactness of the 3D printing concrete is improved after the 3D printing concrete is hardened, and the mechanical and anti-permeability properties of the hardened 3D printing concrete are improved.

The application relates to the technical field of ceramic preparation, and provides a preparation method of high-thermal-conductivity aluminum nitride ceramic, which solves the problems of relatively poor thermal conductive performance and bending strength of the aluminum nitride ceramic prepared by the prior art; the method comprises the following preparation steps: 1) raw material preparation; 2) ball milling mixing; 3) preheating reduction; and 4) hot-pressing sintering.

The utility model relates to the technical field of aquaculture equipment, and provides fry water circulation culture equipment which comprises a culture pond and a water circulation system, the water circulation system is used for recycling water in the culture pond, and a partition assembly is arranged in the culture pond; the partition assembly comprises a supporting frame connected into the culture pond in a sliding mode and a partition net arranged on the supporting frame and capable of preventing fish fries from passing through. A weighting block which is always in contact with the bottom of the culture pond is arranged at the bottom of the partition net. The device can simply achieve the effect of training fries through net pulling, does not need extra power, can recycle water in the culture pond through the water circulation system, prevents sludge from being accumulated at the bottom of the culture pond, and improves the survival rate of the fries.

The present invention discloses a multi-supervisory lane line semantic segmentation method integrating edge detection, including: edge detection of the label truth value corresponding to the input image to obtain the lane line label edge map; the image is input into the encoding network module for feature extraction to obtain a high-resolution feature map and a high-semantic feature map; after upsampling the high-semantic feature map, a splicing operation is performed with the high-resolution feature map along the channel dimension, and the high-resolution feature map is sent to the convolution layer for dimension reduction and then upsampled twice; the high-resolution feature map is upsampled; the label truth map is used as the main supervision signal, and the label edge map is used as the auxiliary supervision signal to calculate the loss function value; the loss function value is weighted and accumulated to optimize the network structure parameters; and the lane line detection model is trained until convergence. The present invention performs semantic segmentation on the driving road condition image, and adds the traditional machine vision edge detection signal for auxiliary supervision during the network training process, thereby improving the accuracy and robustness of the detection result.

The invention relates to the field of batteries, aims to solve the problems that an existing sulfur / carbon composite positive electrode is poor in conductivity and is not beneficial to rapid transmission of electrons, and particularly relates to a preparation method of an extraction residue-based porous carbon electrode material. According to the preparation method, eucommia ulmoides bark is used as a main raw material, besides carbon, a small amount of polar elements such as O, H, N and S remain in the biomass porous carbon material prepared from the eucommia ulmoides bark, the adsorption performance and the ion exchange performance of the biomass porous carbon material are improved, the activated eucommia ulmoides porous carbon has a developed pore structure and a large specific surface area, and the adsorption performance and the ion exchange performance of the biomass porous carbon material are improved. Then graphene oxide and a reinforcing modifier are used for modifying the activated porous carbon, so that the dispersity and binding force of the activated porous carbon are improved, the conductivity of the activated porous carbon is enhanced, rapid transmission of electrons is improved, and the comprehensive performance of a battery prepared from the residue-based porous carbon electrode material is improved.

The invention discloses intelligent high-pressure casting equipment of a speed-regulating and pressurizing feeding system, and belongs to the technical field of casting, the intelligent high-pressure casting equipment of the speed-regulating and pressurizing feeding system comprises a mold base, a mold and a support mounting plate, a material cup is arranged at the bottom of the support mounting plate, the top of the material cup penetrates through the mold base and is connected to a liquid injection opening of the mold, and the mold base is connected with the support mounting plate; a support is fixedly installed at the bottom of the support installation plate, an upper supporting plate and a lower supporting plate are installed on the inner side of the support, a material cup moving oil cylinder is installed at the bottom of the lower supporting plate, an output shaft of the material cup moving oil cylinder is fixedly connected with a top plate, and a guide column is vertically and fixedly connected to the top plate. Molten aluminum can be conveyed into a material cup through inert gas by adopting mold locking force of a horizontal high-pressure casting machine, slow feeding and high-pressure upsetting can be achieved, the mechanical performance of a final casting is guaranteed, slow feeding is achieved through a control system, scouring of a high-pressure casting rapid feeding mode to a mold is reduced, and the service life of the mold is prolonged.

The utility model relates to a fixed induction type telescopic protective fence which comprises a main control box, a telescopic handrail and a terminal box, one end of the telescopic handrail is hinged to the main control box, and the other end of the telescopic handrail is hinged to the terminal box; the telescopic handrail is composed of a plurality of hollow pipes which are hinged in sequence; an electric field induction type detector and an alarm are arranged on the main control box, and a detection line group of the electric field induction type detector penetrates through middle holes of all the hollow pipes and then is connected with the alarm; according to the utility model, through the arrangement of the electric field induction type detector and the alarm, when a person invades, an electromagnetic field in a detection area is interfered, so that the induced voltage output by the induction line is changed, and as long as the change in the aspects such as the amplitude and the rate of signal change or the duration of interference exceeds a specified threshold value, the alarm can give an alarm. The alarm can give an alarm; therefore, the anti-theft protective fence can give an alarm when an intruder climbs over the protective fence, and the protective performance of the protective fence is improved.