29results about How to "Large aspect ratio" patented technology

The invention relates to a method for continuously preparing a single-walled carbon nanotube, which comprises the following steps of: uniformly mixing organic metal and a growth promoter in proportion to form a catalyst, adding the catalyst into a dust spraying device, connecting each gas pipeline and a preheating furnace inlet, connecting an outlet of the preheating furnace with a vertical tube furnace, and sealing the whole device; firstly introducing inert gas to remove air, then preheating the furnace, and heating the vertical tube furnace; after the temperature is stable, the injection device injects a catalyst into the preheating furnace, the preheating furnace and the vertical tube furnace are kept at the constant temperature, and the single-walled carbon nanotubes continuously grow; after the catalyst is consumed, stopping gas supply, turning off a power supply, and taking a sample at room temperature. The catalyst is fully preheated before entering a vertical tube furnace, and the reaction activity of the catalyst reaches the highest; the temperature in the furnace chamber of the reactor is constant, organic gas is fully contacted with a catalyst, carrier gas and reducing gas and is uniformly heated, and continuous growth of the carbon nanotubes is facilitated; the energy consumption is low, the occupied area is small, the operation is simple, continuous production can be realized, the productivity is high, the length-diameter ratio is large, the G / D value is large, and the specific surface area is large.

The invention discloses a high-strength waterproof and oil-proof green paper-based packaging material and a preparation method thereof. The high-strength water-proof and oil-proof green paper-based packaging material is obtained by coating a wet paper web with carboxylated wood nanocellulose and then carrying out hot pressing and drying, the wet paper web is obtained by mixing bamboo pulp, bagasse pulp and wood nanocellulose prepared by a mechanical method, dispersing the mixture in an aqueous solution, making paper with the wet paper web with the water content of 50-60%, and squeezing at normal temperature to remove water until the water content is 20-30%. The paper-based barrier material is prepared by using plants as raw materials and regulating and controlling the fiber paper-based structure through functional components of the plants, has the characteristics of high oil resistance, high tensile strength, good water resistance, greenness, safety and degradability, and is particularly suitable for the fields of food packaging, medical treatment and public health and the like.

The invention discloses an eddy current defect detection method based on multi-direction scanning, electronic equipment and a readable storage medium. The basic idea of working is that excitation current with fixed frequency is introduced into the coil so as to generate an alternating excitation magnetic field in the space. The magnetic field sensor is used for measuring the magnetic flux density change caused by the defect at a proper position, so as to sense the defect. By means of the characteristics that the sizes of hole defects in different directions are similar and the length-width ratio of crack defects is large, a proper probe is adopted to conduct continuous motion scanning in multiple directions, and defect classification is achieved by obtaining more defect information. According to the method, after multi-direction scanning based on continuous movement is adopted, information of defects in different directions can be obtained on the premise that the detection efficiency is not seriously influenced, and classification of holes and cracks can be smoothly realized by adopting a proper signal processing method.

The invention provides a microcup device mask, an electronic paper screen and a manufacturing method thereof.The manufacturing method of the electronic paper screen comprises the following steps that S1, a substrate material is conveyed to a gluing mechanism through a first feeding roller shaft, and a first ITO electrode layer is coated with a layer of imprinting glue through the gluing mechanism; s2, feeding the substrate material and the imprinting glue to a micro-cup device mask plate, and carrying out imprinting and exposure by a micro-cup manufacturing mechanism to form a micro-cup device; s3, ink adding equipment adds ink into the microcup device; and S4, pressing the second ITO electrode layer of the packaging film on the microcup device and the ink to form the electronic paper screen. Through the composite manufacturing method based on nanoimprint lithography and contact lithography and the packaging method based on roller-to-roller, manufacturing and packaging of the microcup structure needed by the electronic paper screen are achieved, the production efficiency is high, the product precision is easy to guarantee, the depth-to-width ratio of the microcup is large, and the product using effect is good.

The present invention relates to a high-entropy hydrotalcite-modified carbon fiber photothermal conversion material and a preparation method thereof. The technical scheme is: in a nitrogen or argon atmosphere, the waste fabric is heat-treated at a temperature of 300 to 700°C for 120 to 300 minutes to obtain a carbon fiber with a porous structure; then the metal salt is mixed in an equimolar ratio and stirred at 100 to 200°C for 10 to 25 minutes to obtain a mixed salt melt; then the carbon fiber with a porous structure is immersed in the mixed salt melt for 10 to 30 minutes, taken out, washed with water, and dried to obtain a high-entropy hydrotalcite-modified carbon fiber photothermal conversion material. The present invention has the characteristics of short production cycle, simple process, low cost, cheap and easy-to-obtain raw materials, and large-scale production. The prepared high-entropy hydrotalcite-modified carbon fiber photothermal conversion material has excellent photothermal conversion efficiency and high water evaporation rate.

The present application relates to a kind of biodegradable dark color mulch and its preparation method, and dark color mulch is made of cellulose, hemicellulose and degradable coating.The manufacturing method includes the preparation of dark color mulch substrate, coating layer coating.It specifically includes slurry compounding, beating, additive addition, is formed by papermaking, dehydration, pre-drying, coating, sizing, drying, calendering, product after drying.The local film has good wet strength, light resistance, weather resistance, heat preservation and entropy increasing effect.The results of farmland degradation experiment show that the mulch can be biodegraded after 50~60 days, and the biodegradation rate is more than 90%.

The invention discloses a four-corner snakelike bridge broadband electromagnetic band gap structure, and belongs to the technical field of circuit microwaves. According to the structure, complementary split-ring resonator shape etching is carried out at the center, and the snake-shaped bridge structures are arranged between the adjacent units, so that the inductance between the electromagnetic band gap units is increased, low-frequency-band SSN is effectively suppressed, the bandwidth is relatively wide, and SSN of a stop band can be effectively suppressed. The four sides of the EBG structure are etched into rectangles, and adjacent elements are connected to form a bridge. Compared with a traditional L-bridge structure, the S-shaped structure is designed, so that the surface current path can be increased, and the equivalent inductance and the equivalent capacitance are increased. The gap between the resonant rings generates a gap current and generates a resonant circuit, so that the cut-off frequency can be effectively reduced and the width of a stop band can be improved. The ultra-wide band gap structure takes the suppression depth of-30dB as a standard, can reach an ultra-wide band gap of 23.8 GHz, is obviously superior to a conventional electromagnetic band gap structure, and can better suppress the noise of a synchronous switch.

This invention discloses a gas diffusion layer with multi-level mass transfer channels, its preparation method, and its application. The gas diffusion layer with multi-level mass transfer channels includes a substrate layer and a microporous layer on the substrate layer; wherein the microporous layer comprises carbon black, hollow porous carbon nanofibers, and optionally a hydrophobic binder. This invention uses hollow porous carbon nanofibers as a novel MPL carbon material to synergistically construct a gas diffusion layer with better water vapor management capabilities in conjunction with carbon black particles. The resulting gas diffusion layer exhibits excellent comprehensive performance; its hollow porous structure provides additional water transport channels, improving water vapor transport capacity, thereby enabling the assembled membrane electrode to have better output performance.

The invention discloses an aircraft connecting assembly and an aircraft, and relates to the technical field of aircrafts, the aircraft connecting assembly comprises a fixing shell, the fixing shell is connected with a pair of connecting rods, one side of each connecting rod is slidably connected with an inserting block, the bottom end of each connecting rod is provided with an inserting groove, and one connecting rod is internally and rotatably connected with a wind shielding cloth roll; the aircraft connecting assembly comprises a fixing shell, two pairs of connecting rods are slidably connected to the fixing shell, the connecting rods are slidably connected to a fixing frame through sliding grooves, a supporting rod is slidably connected to the fixing shell, a sliding block is slidably connected to the supporting rod, and a pull rod is rotatably connected between the sliding block and the fixing frame. The sliding block pushes the fixing frame through the pull rod, so that the two pairs of connecting rods rotate oppositely and are aligned and closed together, the two pairs of connecting rods are pulled to be slowly retracted into the two fixing shells through rotation of the lead screw, fixation is firm, looseness is not likely to happen, the wind blocking cloth roll is pulled out and unfolded during landing, and therefore wind resistance is increased and the sliding distance is reduced during landing of the unmanned aerial vehicle.

The present invention discloses a mobile terminal with a built-in anamorphic lens, wherein the mobile terminal is provided with a wide-screen anamorphic lens; the wide-screen anamorphic lens comprises a cylindrical lens group and a spherical lens group, wherein the cylindrical lens group comprises at least a group of negative optical power cylindrical lenses and a group of positive optical power cylindrical lenses. The wide-screen anamorphic lens is provided in the mobile terminal, and the optical characteristics of the cylindrical lens in the wide-screen anamorphic lens can "compress" the incident light entering horizontally, while the incident light entering vertically remains unchanged, so the wide-screen anamorphic lens can compress the wide-screen image into a standard image area, and the compressed image captured by the wide-screen anamorphic lens can be distorted and corrected by an image correction module to obtain a wide-screen picture and video, thereby satisfying the user's demand for wide-screen shooting of the mobile terminal.

The utility model discloses a side pedal for an automobile, which comprises a support fixedly connected to the automobile and provided with a first hinge part and a second hinge part; the pedal body is provided with a third hinge part and a fourth hinge part; the two ends of the first rotating piece are hinged to the first hinge part and the third hinge part respectively, the two ends of the second rotating piece are hinged to the second hinge part and the fourth hinge part respectively, and the first rotating piece is located on the side, facing the outside of the vehicle, of the second rotating piece; the pedal body has an unfolded state and a folded state, and the first rotating piece and the second rotating piece rotate so that the pedal body can be freely switched between the unfolded state and the folded state. According to the utility model, the pedal body has larger transverse movement in the extending process, and the movement amplitude in the height direction is smaller, so that a larger aspect ratio is obtained, and the problem that the pedal body is damaged due to the fact that the pedal body collides with obstacles such as road shoulders in the extending process can be solved.

The present invention provides a rod-shaped calcium carbonate and a preparation method and application thereof. The preparation method comprises the following steps: (1) dissolving a calcium source in deionized water and then adding an acidic solution to mix, thereby obtaining a first mixed solution; (2) adjusting the temperature of the first mixed solution in step (1), adding a weak alkaline solution to adjust the pH, thereby obtaining a second mixed solution; (3) introducing carbon dioxide into the second mixed solution in step (2) to perform a carbonization reaction until the pH of the reaction solution is 7.0 to 7.5, and then aging, filtering, washing and drying to obtain the rod-shaped calcium carbonate. The calcium carbonate prepared by the present invention has a smooth surface, a large aspect ratio, and contains fewer impurities. The preparation process is simple, and it is easy to realize industrialization, and has good application prospects.

The invention discloses a packaging structure and a packaging device. The packaging structure comprises a metal substrate, a ceramic wall body structure and a lead, the ceramic wall body structure and the lead are located on one side of the metal substrate, the ceramic wall body structure comprises at least two cavities, the cavities are communicated with the surface, close to one side of the ceramic wall body structure, of the metal substrate, the lead is connected with the ceramic wall body structure, and the at least two cavities comprise the first cavity and the second cavity. The first cavity and the second cavity are arranged in the first direction, and the first direction is parallel to the surface of the side, close to the ceramic wall structure, of the metal substrate. According to the packaging structure and the packaging device provided by the embodiment of the invention, at least two independent cavities are arranged on the same metal substrate, so that the combined packaging of high-power multi-electronic elements is met, the length-width ratio of a single cavity can be reduced, the problem of cracking caused by mismatching of thermal expansion coefficients of a ceramic wall body structure and the metal substrate is solved, and the service life of the ceramic wall body structure and the metal substrate is prolonged. And the integration level is higher, the cost is lower, and the assembly consistency is better.

The invention discloses an annular explosion propagation device for an explosion-formed projectile warhead. The annular explosion propagation device comprises an upper explosion propagation shell, an explosion propagation grain, an explosion propagation explosive ring, a lower explosion propagation shell and an explosion suppression body which are coaxially arranged. Wherein the booster grain is assembled in an inner cavity of the booster upper shell; a circle of positioning step is arranged at the lower end of the inner wall of the lower booster shell, and the booster explosive ring of an annular structure is assembled in an inner cavity of the positioning step; the booster explosive column is used for receiving detonation signals output by a fuze detonation point, and the booster explosive ring is used for transmitting detonation waves transmitted by the booster explosive column to form annular detonation; the explosion suppression body is assembled in a center hole of the booster explosive ring, the upper booster shell is assembled to the upper portion of an inner cavity of the lower booster shell in a buckled mode, and the lower end face of the upper booster shell is supported on the positioning step so that the upper end face of the booster explosive ring can make contact with the lower end face of the booster explosive column. Wherein the diameter of the booster explosive column is larger than the inner diameter of the booster explosive ring and smaller than the outer diameter of the booster explosive ring.

The invention provides calcium sulfonate lubricating grease and a preparation method thereof, and belongs to the technical field of lubricating grease. The calcium sulfonate lubricating grease comprises the following raw material components in parts by mass: 35-45 parts of overbased calcium sulfonate; the lubricating oil is prepared from the following components in parts by weight: 25-35 parts of an organic solvent, 6-10 parts of water, 1.0-2.1 parts of small molecular acid, 1.1-2.1 parts of small molecular alcohol, 0.2-1.2 parts of a crystal form regulating agent and 35-65 parts of base oil. The preparation method comprises the following steps: (1) mixing the overbased calcium sulfonate and the organic solvent, then adding the crystal form regulating agent, after the crystal form regulating agent is dissolved, adding 3-5 parts of water in the raw material components, heating to 80-100 DEG C, and stirring to react for 1-2 hours; (2) mixing small-molecular acid, small-molecular alcohol and residual water, adding the mixture into the solution obtained in the step (1), stirring and reacting for 5 hours, and standing the reactant after the reaction is finished; and then adding the base oil, reacting and heating to 150-200 DEG C, stirring and reacting to dehydrate, evaporating to remove the solvent, thickening, and grinding to obtain the calcium sulfonate lubricating grease. The produced calcium sulfonate lubricating grease does not need to be subjected to a composite saponification reaction with fatty acid, the preparation process is simple, the high and low temperature performance is excellent, and the problems that existing lubricating grease is poor in colloid stability, high in thickening agent content and incapable of being used at low temperature can be effectively solved.

The invention discloses a lithium battery diaphragm coated with aramid nanofibers and a preparation method of the lithium battery diaphragm, and belongs to the technical field of lithium ion battery materials, the aramid nanofibers with a unique nanoscale structure and excellent mechanical properties and thermal stability are used as a functional coating matrix, zirconium oxide with high hardness and high wear resistance is used as a functional filler, and the lithium battery diaphragm coated with the aramid nanofibers is prepared. A coating design is carried out through a plasma etching technology, and the functionalized lithium battery diaphragm with high safety, high mechanical strength and excellent thermal stability is prepared. The preparation method specifically comprises the following steps: carrying out plasma etching on a PP base membrane, preparing aramid nanofiber dispersion liquid, preparing ANF / ZrO2 / DMSO composite slurry, coating the PP base membrane, carrying out post-treatment and the like, so as to obtain the lithium battery diaphragm. According to the lithium battery diaphragm, the inherent defects of a traditional lithium battery diaphragm in the aspects of thermal safety, mechanical strength, electrolyte wettability and the like can be overcome. The preparation process is simple and controllable, and the obtained functional diaphragm has wide application prospects in the high-end fields of power lithium batteries, energy storage batteries and the like.

The utility model relates to a carrier sleeve, a carrier and coating equipment, the carrier sleeve comprises an insulating cylinder, the outer wall portion of the insulating cylinder is provided with a groove structure in the circumferential direction, the axial section of the groove structure comprises at least two groove sections, and the groove sections are arranged side by side in the radial direction of the insulating cylinder and are sequentially communicated end to end. Through the arrangement of the groove structure, the probability that a continuous polycrystalline silicon layer is formed on the surface of the sleeve along a creepage path can be effectively reduced, the situation of short circuit between two adjacent boat pieces is further reduced, the service life of the sleeve and the boat pieces is prolonged, and the product yield of the substrate is improved.

The invention discloses a wafer-scale system-in-package structure and a forming method thereof. The wafer-scale system-in-package structure comprises a silicon substrate; the plurality of functional sub-modules are attached to the upper surface of the silicon substrate and are arranged in an array; the warping and stress adjusting structure is attached to the upper surface of the silicon substrate at the edge of the functional sub-module; the stress buffering flexible part structure is attached to the upper surface of the silicon substrate of the functional sub-module corner head; the edge false devices are attached to the upper surface of the edge area of the silicon substrate outside the functional sub-module array and are different in size; and the plastic packaging layer is positioned on the upper surface of the silicon substrate and wraps the functional sub-module, the warping and stress adjusting structure, the stress buffering flexible part structure and the edge false device. And the warping of the system packaging structure of the wafer-level super-large core particle module at room temperature or high temperature can be effectively regulated and controlled. According to the method, support of national key research and development plan projects (the project number is 2023YFB4404300, and the project number is 2023YFB4404305) is obtained.

The utility model discloses a high-frequency low-noise high-speed motor rotor, which comprises a rotating shaft, a permanent magnet, a permanent magnet protective sleeve and fan blades, the permanent magnet is fixedly sleeved on the rotating shaft, the number P of pole pairs of the permanent magnet is 2, the permanent magnet is formed by overlapping N annular permanent magnet sheets, and N is greater than or equal to 2; the permanent magnet protection sleeve is fixedly sleeved on the outer side wall of the permanent magnet; the fan blade comprises an impeller and 17 blades, the impeller is fixedly arranged on the rotating shaft in a penetrating manner; the rotating shaft, the permanent magnet, the permanent magnet protection sleeve and the impeller are coaxially arranged. According to the utility model, the number of the blades is increased to 17, so that the sound frequency can still be effectively improved under the condition that the rotating speed of the motor is reduced, and the sound frequency is not within 3000Hz-4000Hz which is uncomfortable for people, so that the noise can be effectively eliminated, and the use comfort of the high-speed motor is improved; the number of pole pairs of the permanent magnet is two, so that the iron loss can be reduced, and the use efficiency of the high-speed motor is improved.

The present invention belongs to the technical field of special materials for PE pipes, and specifically relates to an ultra-large-caliber PE pipe material and its preparation method and application. The present invention first provides a modified whisker carbon nanotube masterbatch, wherein the whisker carbon nanotube is grafted with a phase change microsphere having a phenolic resin as a shell and n-hexadecane as a phase change core material, and the masterbatch is mixed with PE resin and kneaded to form a masterbatch, and then further made into an ultra-large-caliber PE pipe material with PE resin and carbon black masterbatch. The obtained ultra-large-caliber PE pipe material has good tensile fracture rate and anti-aging performance, and other properties also meet the relevant standard requirements of PE pipes.

The utility model discloses a linear warmer which comprises a tube with the axis horizontally extending left and right, two ends of the tube are respectively provided with a cover plate, two axial flow fans close to one end are arranged in the tube, the air inlet end faces of the axial flow fans face the cover plates, the air outlet ends of the axial flow fans are opposite to the cover plates, air inlets are formed in the cover plates, and air outlets are formed in the cover plates. A partition plate is arranged between the two axial flow fans, a mounting hole is formed in the partition plate, a PTC heating body is embedded in the mounting hole, a cold air channel located above the partition plate and a hot air channel located below the partition plate are formed between the partition plate and the bobbin, and spoilers for separating the hot air channel from the cold air channel are arranged at the two ends of the hot air channel respectively. An air outlet formed in the bobbin is formed in the lower portion of the PTC heating body. The warmer has the advantages of being large in length-width ratio of the air outlet and wide in air outlet radiation range, and is complete in overall function and high in practicability.

The invention discloses a preparation method of a high-length-diameter-ratio silver nanowire, and aims to solve the technical problem of how to obtain a silver nanowire which is uniform in morphology and higher in length-diameter ratio. The silver nanowire is prepared through a hot solvent method, the concentration of AgNO3 in a reaction solution D is 70-80 mmol / L, the volume ratio of a reaction solution A to the reaction solution D is 45-55: 23-33, the reaction temperature is 165-175 DEG C, and the reaction time is 145-155 min. The silver nanowire synthesized through the method is good in uniformity, high in purity and large in length-diameter ratio, the average diameter of the silver nanowire is 38.88 nm, the average length of the silver nanowire exceeds 100, the length-diameter ratio of the silver nanowire exceeds 2500, and the silver nanowire can be used for preparing the silver nanowire. The method has important guiding significance in application of the silver nanowires in the fields of transparent electrode materials and the like.

The present invention discloses a laser radar scanning method and a computer-readable storage medium. The method comprises: a first light deflection device deflects a light beam emitted by a light source by a plurality of first deflection angles along a first direction; the length of the light beam emitted by the light source along the first direction is less than the length along a second direction; a second light deflection device deflects the light beam deflected by the first light deflection device by a plurality of second deflection angles along a first direction and a second direction to project a scanning light beam; the length of the scanning light beam in the first direction is less than its length in the second direction; the second deflection angle of the incident light beam deflected by the second light deflection device is adjusted by controlling the working voltage applied to the second light deflection device, and the corresponding working voltage applied is fine-tuned according to the incident angle of the light beam incident on the second light deflection device; wherein, for the same second deflection angle, different incident angles correspond to different working voltages.

The invention belongs to the technical field of building structure health monitoring, and particularly relates to a hollow slab bridge regional distribution rigidity identification method based on vision measurement, which can realize regional rigidity identification of a hollow slab bridge. The method comprises the following specific steps: under the action of random traffic load, carrying out vehicle reference point positioning and vehicle information identification by using a traffic flow monitoring camera on a bridge, and obtaining the position and size of the vehicle load on the bridge floor at any moment by combining the vehicle weight data of a toll station; when the load of the bridge floor is identified, the corner of each test unit node in the test bridge area is synchronously monitored by using an under-bridge online camera; according to the position and size of the bridge deck vehicle load at any moment, calculating the bending moment envelope area of each rigidity identification area at any moment by utilizing a matrix displacement method based on a beam lattice model; calculating the curvature envelope area of each rigidity identification area according to the monitored rotation angle of the unit node; performing quotient on the bending moment envelope area and the curvature envelope area of each region, and taking a mean value at a time scale to obtain the uniform rigidity of each test unit; according to the uniform rigidity of each test unit, calculating a standardized rigidity damage index to identify structural damage; if the identified structure is not damaged, ending the measurement; and if the identified structure is damaged, considering the internal force redistribution effect after the regional rigidity is damaged for the damaged structure, and updating beam lattice model parameters by using an iteration method until convergence to obtain the regional rigidity under the damage. According to the method, large width span ratio and obvious transverse distribution effect of the hollow slab bridge are considered, structure bending moment distribution is calculated by utilizing a matrix displacement method based on a beam lattice model, and the method is rapid and convenient, high in testing precision and suitable for rapid testing of regional distribution rigidity of the hollow slab bridge.

This invention provides a multi-turn silver nanoring and its preparation method, belonging to the field of metal nanomaterial preparation technology. The invention first mixes a polyvinylpyrrolidone (PVP) glycol solution with pyridine to obtain a mixed solution; then, the mixed solution, a sodium halide glycol solution, silver nitrate, and sodium nitrate are mixed, followed by a solvothermal reaction and precipitation separation to obtain multi-turn silver nanorings. The method for preparing multi-turn silver nanorings is simple, easy to implement, has good reproducibility, and high yield. During the preparation process, the addition of the organic solvent pyridine enables the silver nanowires to bend and grow significantly to form multi-turn silver nanorings.

This invention discloses a two-way combined group-mode precision compression process, including the following steps: Step (1): Explosive preparation, optimizing the explosive formula, improving the physicochemical properties of the explosive particles, utilizing reasonable particle gradation and explosive crystal spheroidization technology to reduce the porosity between explosive particles, and secondly, using highly dense spheroidized black oxojin and octogen high-energy explosive particles with smooth surfaces and shapes as close to circles as possible to reduce crystal defects and improve crystal density and compressibility. The process of this invention achieves precise clustering and two-way compression of multiple explosive columns on a conventional upward-moving unidirectional press, which is economical, widely applicable, and highly efficient. The prepared explosive columns have the advantages of large aspect ratio (≥2), high density and uniform distribution (density difference ≤0.5%), high energy, and good quality.

The invention discloses a composite microporous membrane, a preparation method thereof and a battery, belongs to the technical field of lithium ion batteries, and overcomes the defect that a heat conduction material in the prior art has a poor improvement effect on the heat conductivity of the microporous membrane. The composite microporous membrane comprises a base membrane and a heat-conducting coating arranged on at least one side of the base membrane, the heat conduction coating comprises a silicon nitride nanowire; the mass of the silicon nitride nanowires is 86-98.5 wt% of the mass of the heat-conducting coating; the length-diameter ratio of the silicon nitride nanowire is 50-400, and the length of the nanowire is 20-100 [mu] m. The composite microporous membrane provided by the invention has good thermal conductivity.

This invention relates to the field of polymer materials and discloses a modified polypropylene material and its application in HPPM double-wall corrugated pipes. The modified polypropylene material comprises: polypropylene resin, modified graphitic carbon nitride, modified multi-walled carbon nanotubes, and additives. The modified graphitic carbon nitride is prepared by grafting a hindered amine-type bromine-substituted intermediate with amino-modified graphitic carbon nitride. The hindered amine-type bromine-substituted intermediate is prepared by reacting ethyl 2-amino-4-methylthiazolium-5-carboxylate with 1,4-dibromobutane and then undergoing transesterification with 2,2,6,6-tetramethyl-4-piperidinol. The modified multi-walled carbon nanotubes are prepared by grafting acyl chloride multi-walled carbon nanotubes with a cyclotriphosphazene derivative. The cyclotriphosphazene derivative is prepared by reacting 4-imidazolium formaldehyde with p-phenylenediamine, then undergoing substitution with hexachlorocyclotriphosphazene and further addition with DOPO. The modified polypropylene material prepared by this invention possesses good mechanical properties, UV aging resistance, flame retardancy, and antibacterial properties.

The present invention relates to a nanofiber cluster-shaped bismuth vanadate gas-sensitive material and a preparation method thereof, which is composed of a nanofiber stacked fiber cluster and independently dispersed nanofibers, wherein the diameter of the independently dispersed nanofibers is 5 to 50 nm, the diameter of the nanofiber stacked fiber cluster is 10 to 500 nm, and the nanofibers contain fiber gap micropores less than 2 nm, and the nanofiber stacked fiber clusters and the independently dispersed nanofibers overlap each other to form macropores of 50 to 150 nm. Preparation method: prepare a dilute nitric acid solution; dissolve bismuth nitrate pentahydrate and ammonium metavanadate in the dilute nitric acid solution respectively; add the ammonium metavanadate mixed solution dropwise to the bismuth nitrate mixed solution; add ammonia water; solvent thermal reaction; centrifuge; pour in anhydrous ethanol and rotate and shake; centrifuge and wash. This patented method does not require roasting, has low energy consumption, and is simple in process. The material of the present invention has high sensitivity to ethylene glycol gas, short response recovery time, and low operating temperature.