70results about How to "Effective diffusion" patented technology

The invention provides a method for improving the stability of a perovskite nanocrystal, which comprises the following steps: S1, preparing the perovskite nanocrystal: mixing a perovskite nanocrystal precursor and a micro / mesoporous template to obtain a mixture; calcining the mixture under the condition that the collapse temperature of the micro / mesoporous template is lower than that of the micro / mesoporous template, so as to generate perovskite nanocrystals in the pore channels of the micro / mesoporous template; s2, post-treatment by a hydrothermal method; and S2, dispersing the perovskite nanocrystals obtained in the step S1 in a high-pressure reaction device filled with an inorganic fluoride solution, and treating the mixed solution through a hydrothermal method to obtain the perovskite illuminant. According to the method, the stability of the perovskite nanocrystals can be improved without collapsing the micro / mesoporous template.

The invention discloses a grouting reinforcement method for a coal mine working face collapse and burst broken area, which comprises the following steps: S1, on-site investigation and survey are carried out, end face leakage and burst conditions are mastered, and collapse and burst broken reasons are quantitatively analyzed from two aspects of geological factors and engineering factors; s2, the grouting opportunity, the grouting position, the grouting material and the grouting parameters are determined through theoretical calculation, physical experiments and numerical simulation; and S3, a deep and shallow hole grouting mode is adopted for conducting grouting reinforcement on the caving and breaking area of the coal mine working face. According to various factors of coal mine working face collapse, a grouting mode combining deep and shallow holes is provided in a targeted mode, low-pressure slow grouting is adopted for the shallow holes, the shallow holes are used for sealing coal cracks in the working face superficial range, forming a curtain and preventing grout from leaking, floral tube grouting is adopted, the grout diffusion path is increased, and effective diffusion of grout is guaranteed; then deep hole grouting is carried out, and grouting modification is carried out on the coal body with the relatively low deep fracture development degree; therefore, the completeness and strength of the advanced coal body of the working face are improved, the caving condition is improved, top coal and a top plate are better supported, and then top coal leakage is controlled.

The invention discloses a high-density liquid cooling server and a server cabinet system, and relates to the technical field of liquid cooling servers, the server cabinet system comprises an equipment cabinet, an assembly plate is mounted in the equipment cabinet, a circulating pump is mounted above the assembly plate, two sides of the circulating pump symmetrically communicate with liquid cooling pipelines, the front side of the circulating pump communicates with a liquid storage tank, and the front side of the liquid storage tank communicates with a liquid storage tank. A strain constant-temperature mechanism is arranged on the front side of the assembly plate and used for flexibly conducting heat dissipation treatment on the assembly plate, and the cold liquid regulation and control mechanism is used for enabling cooling liquid to generate a spiral flowing track in the flowing process. Targeted heat dissipation management of a high-temperature area is achieved, when it is detected that the temperature of a specific area is abnormally increased, the circulation paths of cooling liquid in the upper area and the lower area can be synchronously adjusted in time according to the change of temperature increase, and the circulation area of a channel is reduced by dynamically adjusting and distributing the flow of the cooling liquid and combining temperature flexibility.

The invention relates to a solar cell, a preparation method thereof and a photovoltaic module. The solar cell comprises a semiconductor substrate which is provided with a first surface and a second surface which are opposite to each other, the first surface is provided with a first doped region and a second doped region which are arranged in a staggered mode, the second doped region comprises a contact region and isolation regions located on the two sides of the contact region, and the isolation regions are connected with the first doped region; the first doped layer is positioned in the first doped region; the first isolation layer is located in the isolation region; the second doping layer at least covers the contact region and one side, deviating from the semiconductor substrate, of the first isolation layer; the conduction type of the second doping layer is opposite to that of the first doping layer; and a first electrode and a second electrode, the first electrode being in electrical contact with the first doped layer, and the second electrode being in electrical contact with the second doped layer located in the contact region. The isolation effect can be improved.

The invention discloses electroplating sewage treatment equipment and method, and relates to the technical field of sewage treatment. Comprising an equipment body, a medicament adding assembly and a cleaning assembly, the medicament adding assembly and the cleaning assembly are fixed to the outer wall of the equipment body, a screening assembly used for intercepting precipitates and an adsorption assembly used for pumping sewage are arranged in the equipment body, and the equipment body comprises a main box body; the agent adding assembly comprises a plurality of agent boxes fixed to the outer wall of the main box body, and adding pumps are fixedly connected to the tops of the agent boxes. According to the sewage treatment device, chemicals are added into the main box body in a small amount and multiple times according to a set sequence, so that the chemicals are fully diffused in sewage and fully react with the sewage, and precipitates generated in the reaction process can be continuously intercepted and screened out in the reciprocating lifting process of the lifting plate; the diffusion effect of the medicament in the sewage is better facilitated, the treatment capacity of the medicament is improved, and the influence of precipitates on the diffusion of the medicament is prevented.

The invention belongs to the field of silicon carbide powder synthesis, and particularly relates to a silicon carbide powder synthesis crucible and a use method. The silicon carbide powder synthetic crucible is formed by vertically stacking single-layer crucibles with the same structure along the central axis of a graphite crucible; the single-layer crucible comprises a crucible upper cover, a graphite sheet and a crucible main body; the crucible upper cover and the crucible main body are nested; the bottom of the inner cavity of the crucible main body is used for placing silicon powder and graphite powder; and the graphite flake is clamped between the crucible upper cover and the crucible main body. By designing the height of the single-layer crucible and the structure of the multi-layer crucible, a proper temperature gradient is favorably constructed, and by controlling parameters such as heat preservation time and pressure, batch production of large-particle-size and high-uniformity silicon carbide powder is realized, and an ideal raw material is provided for growth of high-quality silicon carbide crystals.

The invention belongs to the technical field of battery negative electrode materials, and particularly relates to a phosphorus-based negative electrode material with a coating structure as well as a preparation method and application of the phosphorus-based negative electrode material. On the basis of the prior art, nano nickel phosphide, red phosphorus and carbon nanospheres are subjected to ball milling to prepare a main body phosphorus-based material, and then the main body phosphorus-based material is coated with a coating layer prepared from a nanofiber material, pyrrole and 5-azaindole, so that the coating layer of the phosphorus-based negative electrode material has elasticity, the volume expansion rate of the phosphorus negative electrode material is reduced, and the service life of the phosphorus negative electrode material is prolonged. According to the nickel phosphide-based negative electrode material and the preparation method thereof, the interface interaction between the phosphorus-based negative electrode material and the binder is enhanced, the prepared nickel phosphide grows on the black phosphorus nanosheet, so that the nickel phosphide has good dispersity, the nickel phosphide nanocrystals can be effectively prevented from being agglomerated, and the energy storage capacity of the nickel phosphide is improved; and after the 5-hydroxy vanillin is grafted, the adhesive has excellent wet adhesion resistance, and can prevent the dissolution of phosphorus element, so that the cycle efficiency of the electrode is improved.

The invention provides a preparation method of a diaphragm-free all-solid-state battery, and belongs to the technical field of solid-state batteries, and the preparation method comprises the following steps: S1, coating the surface of a positive current collector with positive slurry to obtain a positive plate; s2, coating the surface of the positive plate with acting slurry to form an acting layer; the acting slurry comprises the following components in percentage by mass: 15-18% of lithium niobate, 5-6% of nano aluminum oxide, 3-5% of a binder and the balance of a solvent; s3, coating the surface of the acting layer with electrolyte slurry to form a semi-solid electrolyte; the electrolyte slurry comprises the following components in percentage by mass: 5-7% of porous carbon coated alumina particles, 7-9% of a binder and the balance of electrolyte; s4, the surface of the semi-solid electrolyte is coated with negative electrode slurry, then a negative current collector is added, the surface is pressurized by 450-650 N / m < 2 >, heating treatment is conducted for 12-15 h at the temperature of 80-100 DEG C in an inert environment, and a battery cell body is obtained; and S5, packaging, compacting and sealing the battery core body to obtain the diaphragm-free all-solid-state battery. According to the invention, the cycle life of the prepared diaphragm-free all-solid-state battery can be prolonged.

The utility model relates to the technical field of electrostatic dust collection, and provides hot galvanizing zinc niacin acid mist electrostatic trapping treatment equipment which comprises a device, one side of the device is fixedly communicated with an air inlet smoke box, one end of the air inlet smoke box is fixedly connected with an air inlet pipe, and a guide plate is arranged in the air inlet smoke box. The driving mechanism can utilize the power of smoke to drive the smoke expanding assembly to operate, the smoke expanding assembly can drive the guide plate to swing up and down in a reciprocating mode, the smoke can be dispersed to a wider area, the local concentration is reduced, the smoke is more evenly distributed in the device, and therefore zinc nicotinic acid mist is effectively guided and diffused, and the smoke diffusion efficiency is improved. The dust removal effect is maximized; the anti-blocking component is designed to be matched with the smoke expanding component, so that residual dust particles in the guide plate can be shaken off while the guide plate shunts guided smoke, the risk of blocking the guide plate is reduced, and the stability and the reliability of the device are improved.

The invention provides a transverse excitation bulk acoustic wave resonator for improving power tolerance and application thereof, the transverse excitation bulk acoustic wave resonator comprises supporting areas, resonance areas and anchors, the supporting areas are located at the two ends of the transverse excitation bulk acoustic wave resonator, the resonance areas are located between the supporting areas at the two ends, and the anchors are located at the two ends of the transverse excitation bulk acoustic wave resonator. The resonance area is connected with the supporting areas at the two ends through anchors; a cavity is further formed between the supporting areas at the two ends, and the cavity is located below the resonance area and the anchor; the resonance area comprises a composite film and at least two interdigital metal electrodes on the surface of the composite film, the composite film comprises a first heat conduction material layer and a first piezoelectric material layer which are stacked, and the interdigital metal electrodes are arranged on the surface of the first piezoelectric material layer. The transverse excitation bulk acoustic wave resonator has the characteristic of high power resistance, and still has the excellent acoustic performance of the resonator.

The invention discloses a strain for producing pectinase and application of the strain in hemp degumming, and belongs to the technical field of microorganisms. The classification name of the strain for producing pectinase is talaromyces wortmannii, the preservation unit is China General Microbiological Culture Collection Center, the preservation name of the strain is HM01, the preservation number is CGMCC No, 41378, and the preservation date is June 20, 2024; the strain generates pectinase and does not generate cellulase, and the strain fermentation liquor is sprayed to the hemp stems, so that the strain can be colonized and grow on the epidermis of the hemp, and the degumming effect of the hemp can be improved; the device effectively improves the rain and dew degumming effect of the China-hemp, accelerates the rain and dew degumming speed, improves the separation effect of hemp skins and hemp stems of the China-hemp, and promotes the high-quality development of the China-hemp fiber industry.

The invention discloses a copper and copper alloy strip edge watermark removing device, and relates to the technical field of copper strip production, the copper and copper alloy strip edge watermark removing device comprises a copper strip body and a fixing plate, the side, away from the copper strip body, of the fixing plate is fixedly connected with a programmable controller, and the side, away from the fixing plate, of the programmable controller is provided with an air compression device; a nozzle is fixedly connected to an opening of the air compression device and used for blowing compressed air to the edge of the copper strip body at a certain angle and speed. The device has the main advantages that through the stepping motor, the moving body, the air compression device and the nozzle, water stains on the edge of the strip can be removed through compressed air, and the compressed air can quickly blow away the water stains on the edge of the strip through high-speed airflow and certain pressure of the compressed air. Therefore, the drying time in the production process can be remarkably shortened, and the production efficiency is improved.

The invention relates to the technical field of composite gas diffusion layers, in particular to a corrosion-resistant composite gas diffusion layer and a preparation method and application thereof. The preparation method comprises the following steps: mixing alkaline metal molten salt and a chromium-containing active substance to obtain mixed active alkaline metal molten salt; preheating the microporous layer to obtain a preheated microporous layer; heating the mixed active alkaline metal molten salt in a vacuum environment to obtain a mixed active melt; the preheated microporous layer is immersed in the mixed active solution for a disproportionation reaction, and a crude product composite gas diffusion layer is obtained; cooling the crude product composite gas diffusion layer, and purifying to obtain the composite gas diffusion layer; the raw material of the microporous layer comprises carbon nanotubes, and the raw material of the substrate layer comprises carbon fibers; the weight m1 of the alkaline metal molten salt and the weight m2 of the chromium-containing active substance meet the relational expression: m1: m2 = (5: 1)-(10: 1). According to the preparation method, the corrosion resistance and the porosity of the composite gas diffusion layer can be synchronously improved.

The invention discloses a cardiovascular disease auxiliary prevention reminding system based on deep learning, which comprises a shell, the top of the outer surface of the shell is fixedly provided with a display screen, and the top of the inner cavity of the shell is fixedly provided with a data acquisition module, a data transmission module, a data processing module and a buzzer in sequence from left to right. Through the arrangement of the data acquisition module, the physiological monitoring module, the data transmission module, the data processing module, the deep learning analysis module, the central control module, the buzzer and the personalized suggestion module, multiple health information of a user is acquired; the health condition and the disease risk of the user can be judged timely and effectively, and personalized health guidance can be performed according to the health condition and the disease risk of the user, so that the user can adjust corresponding living habits, daily exercises and diet according to own health, and the purpose of preventing cardiovascular diseases is achieved.

The present invention relates to the technical field of cardboard shredding, and discloses a cardboard shredder, comprising a workbench, a support frame is fixedly connected to the top of the workbench, a shredding box is fixedly connected to the top of the support frame, two opposing pressure rollers are rotatably connected to the inside of the shredding box, a plurality of shredding blocks are fixedly connected to the outer walls of the two opposing pressure rollers, a lower hopper is fixedly connected to the top of the shredding box, a transmission mechanism is arranged at the bottom of the shredding box, a separation assembly is arranged at the bottom of the transmission assembly, a vibration assembly is arranged between the transmission assembly and the separation assembly, and the transmission assembly continuously transports the shredding by allowing the shredded debris to enter the transmission assembly, thereby avoiding accumulation that causes the cardboard fragments and pulp in the debris to be unable to be completely screened, and during the transmission of the debris, the cardboard fragments and the pulp will be screened and separated, so that the screening process can be kept unobstructed, and the continuity and efficiency of the pulp preparation process can be ensured.

The application discloses a leak stopping method for directional drilling of ground pre-grouting engineering in complex strata, which comprises the following steps: lowering a grouting drill rod to a leaking layer, continuously injecting clay cement slurry, waiting for the slurry to solidify, lowering the drill rod to sweep the hole and pass through the leaking layer; when the clay cement slurry cannot successfully stop the leak in the drilling of a serious leaking layer, a leak stopping casing with an outer diameter smaller than the inner diameter of a previous drilling structure casing and an inner diameter larger than the outer diameter of a next drilling structure casing is lowered to the depth of the leaking layer before lowering the next drilling structure casing, a grouting pipe is connected to the leak stopping casing, single liquid cement slurry is injected, and the grouting is stopped after the pressure is increased to a set pressure, and the leak is successfully stopped after the cement slurry is solidified, and the drilling construction passes through the leaking layer. The application ensures the effective diffusion of the slurry in the leaking layer, avoids the waste of the leak stopping material, improves the pertinence of the leak stopping, and improves the plugging success rate of the complex strata to more than 95%.

This utility model relates to the field of dust control technology, and in particular to a dust control facility for construction sites, including a handcart. The handcart is equipped with a dust control mechanism for dust control. The dust control mechanism includes: a spray assembly, including a frame fixed on the handcart, a circular plate fixed to the front end of the frame, an arc-shaped tube fixed to the front end of the circular plate via a fixing bracket, a plurality of circumferentially distributed atomizing nozzles installed at the front end of the arc-shaped tube, a cylinder seat fixed to the front end of the circular plate, and a fan blade installed inside the front end of the cylinder seat; a water supply assembly, mounted on the frame and used for water supply; and a drive device, mounted on the frame and used for power supply. Through the circumferential layout of the arc-shaped tube and the circumferential distribution of the atomizing nozzles, the water mist spray range expands in a ring shape. Combined with the airflow propulsion effect of the fan blades, the dust control facility significantly improves the capture efficiency and settling speed of airborne dust.

The utility model relates to the technical field of passenger car license plate lamps, and discloses an automobile uniform light license plate lamp which comprises a lamp shell upper half part, a lamp holder is arranged at the top end in the lamp shell upper half part, six LED lamp tubes are arranged on the lamp holder, the six LED lamp tubes are distributed in a V shape with the top end in the lamp shell upper half part as the center, and the LED lamp tubes are arranged in the lamp shell upper half part. The six LED lamp tubes do not influence one another; a transparent protective shell is arranged on the front face of the upper half portion of the lamp shell. The inner side patterns, the middle patterns and the outer side patterns are equal in width. According to the utility model, the optical patterns in the lamp housing are divided into areas for dialling light; the inner side patterns change the light rays which are directly irradiated to the license plate lamp by the LED, so that the light rays deflect towards the middle of the license plate; the middle patterns gather LED longitudinal light rays and effectively diffuse the light rays to the middle and the width part of the license plate; and the outer side patterns supplement the outward light of the LEDs to the lowermost end of the license plate, so that the light is flatly laid on the license plate, the uniformity of the lamp after loading is improved, and modular management of the lamp is facilitated.

The present invention relates to the technical field of methacrylate synthesis, and specifically discloses a molecular sieve catalyst for methacrylate synthesis and a preparation method thereof. The above-mentioned catalyst preparation method includes: adding type A microporous molecular sieve to anhydrous ethanol and ultrasonically treating at room temperature for 1-2h, adding ethylenediamine, stirring at 50-70°C for 1-2h, and removing anhydrous ethanol by rotary evaporation to obtain a pre-treated molecular sieve; adding the pre-treated molecular sieve, yttrium nitrate, and tetraethyl orthosilicate to an ethanol aqueous solution and stirring evenly, adjusting the system pH value to 8-9, 80-90°C insulation for 5-10h, cooling to room temperature, washing, and vacuum drying to obtain a composite molecular sieve; calcining the composite molecular sieve at 300-500°C for 2-4h, cooling to room temperature, adding to water, adding zirconium nitrate, cesium nitrate, and graphene oxide for ultrasonic treatment for 5-10h, standing for 5-10h, 160-190°C hydrothermal reaction for 2-6h, cooling to room temperature, filtering, washing, and vacuum drying.

The invention belongs to the technical field of aqueous batteries, and discloses a preparation method of an ant nest-shaped carbon material and a zinc-iodine soft package battery. The preparation method comprises the following steps: (1) preparing a ZIF-8 material from zinc nitrate hexahydrate and 2-methylimidazole; (2) calcining the material prepared in the step (1) to obtain an ant nest-shaped carbon material; the zinc-iodine soft package battery comprises a zinc foil negative electrode, an ant nest-shaped carbon material positive electrode, a glass fiber diaphragm and an electrolyte, the obtained ant nest-shaped carbon material has a high specific surface area and a rich pore structure, can effectively bear and limit an iodine active substance, and improves the effective utilization rate of an iodine simple substance; the dissolution and diffusion of intermediate product polyiodide ions can be limited, and the shuttle effect is inhibited; the price is low, the preparation method is simple and convenient, and the repeatability is high; and the aqueous electrolyte and the graphite paper current collector are adopted, so that dangerous conditions such as combustion or explosion and the like are not easy to occur. And meanwhile, the application of the graphite paper current collector shows the trend of increasing the energy density.

The invention discloses a laser additive manufacturing titanium-steel multi-material component, a device and a method thereof. According to the laser additive manufacturing titanium-steel multi-material component, element diffusion is inhibited through a middle layer, and interface bonding and forming performance are improved. The laser additive manufacturing titanium-steel multi-material component comprises a titanium alloy layer, a middle layer and a stainless steel layer, wherein the middle layer comprises an elemental metal Ce layer and an elemental metal Cr layer; the titanium alloy layer, the elemental metal Ce layer, the elemental metal Cr layer and the stainless steel layer are sequentially deposited through a laser directional energy deposition process. Therefore, according to the intermediate layer, the elemental metal Ce layer and the elemental metal Cr layer are designed, diffusion of Ti elements in the titanium alloy layer and Fe elements in the stainless steel layer is blocked through the characteristic that Ce and Cr are mutually soluble, and good metallurgical bonding between different materials is achieved; the problems of interface cracking, holes and the like caused by brittle intermetallic compounds when titanium alloy and stainless steel are directly connected are solved.

The invention discloses a residual oil hydrotreating catalyst and a preparation method thereof, and belongs to the technical field of catalytic materials. The preparation method comprises the following steps: S1, mixing dolomite, cerous carbonate, a zirconium oxide precursor and a silicon dioxide precursor, drying and calcining to obtain a composite carrier, and performing in-situ pore forming by utilizing gas generated by decomposition of the dolomite and the cerous carbonate to form a mesoporous structure; s2, dipping the composite carrier in a modification liquid containing chitosan and mannuronic acid, and constructing a cross-linked network coating on the surface of the composite carrier through a Schiff base reaction to obtain a modified carrier; s3, dipping the modified carrier in a precursor solution containing a nickel source, a molybdenum source and a sulfur source, and performing adsorption, drying and roasting to obtain the catalyst. Through the synergistic effect of pore structure regulation and surface modification, the carrier with high porosity and suitable pore distribution is obtained, and meanwhile, high dispersion and stable loading of active metal components are realized. The catalyst shows excellent hydrodesulfurization, denitrification and demetallization performance in residual oil hydrotreatment.

The present invention provides a method for controlling the segmented pressure relief and reinforcement of the tunnel roof based on double tunnel excavation, including: obtaining geological parameters of the coal seam roof; according to the geological parameters, drilling holes obliquely toward the coal seam roof at the side tunnel wall of the coal pillar in the second tunnel, so that the drilled holes pass through the direct roof of the first tunnel and extend into the basic roof of the mining face; based on the section where the drill hole located at the basic roof is located, hydraulic fracturing is performed on the basic roof; based on the section where the drill hole located at the direct roof is located, grouting reinforcement is performed on the direct roof. The present invention not only optimizes the fracturing and grouting operation procedures in terms of technology and improves the operation efficiency, but also can alleviate the influence of the high advanced support pressure and lateral support pressure caused by the difficulty of hard roof collapse on the stability of the tunnel surrounding rock, improve the structural integrity and bearing capacity of the local roof of the tunnel, transfer the stress above the coal pillar in the section to a certain extent, and achieve the purpose of controlling the deformation of the tunnel surrounding rock.

According to the fast-charging negative electrode plate, in the fast-charging negative electrode plate, two sides of a current collector are coated with first graphite layers; the second graphite layer is coated on the first graphite layer, the porosity of the second graphite layer is higher than that of the first graphite layer, and a plurality of lithium ion linear diffusion channels extending vertically are distributed on the top surface of the second graphite layer in an array manner. The fast-charging negative plate has a gradient pore structure with high surface porosity, low tortuosity and low internal porosity, gives consideration to rate capability and energy density, and has a cost advantage.

The utility model relates to a regenerated lubricating oil base oil vacuum steam stripping deodorization device, which comprises a steam stripping tower, a liquid inlet pipe, a gas inlet pipe, a liquid discharge pipe, an exhaust pipe and a vacuum pump, the steam stripping tower consists of an upper tower body, a lower tower body and a middle tower body, the liquid inlet pipe is communicated with the side part of the upper tower body, the gas inlet pipe is communicated with the side part of the lower tower body, and the liquid discharge pipe is communicated with the bottom of the lower tower body; the middle tower body comprises a plurality of horizontal packing cylinders which are distributed up and down, the bottom of the upper tower body is communicated with the top side of the packing cylinder on the uppermost layer, the top of the lower tower body is communicated with the bottom side of the packing cylinder on the lowermost layer, and every two adjacent packing cylinders are communicated through a conveying tower body; one end of the filler cylinder is open and provided with a flange, a cover plate is detachably arranged on the side, away from the filler cylinder, of the flange, a net cylinder is rotationally arranged on the cover plate, and the net cylinder extends into the filler cylinder and is filled with filler. According to the utility model, the full contact between a gas phase and a liquid phase can be realized, the filler can be quickly replaced, and the device is more practical.

The invention provides a non-ground network system orthogonal transformation auxiliary OFDM (Orthogonal Frequency Division Multiplexing) modulation and demodulation method, and relates to the technical field of NTN (Network Temporary Network) communication. The method comprises the following steps: a transmitter encodes and modulates a data stream, and blocks a data symbol sequence; two-dimensional fast Fourier transform is adopted as an orthogonal transformation type, and a diffusion symbol block is obtained through orthogonal transformation and deblocked; normalizing the diffusion symbol sequence and inserting a pilot frequency, and then performing OFDM modulation and adding a cyclic prefix; the receiver performs symbol synchronization and frequency offset compensation on the received symbol sequence, and then removes the cyclic prefix and performs OFDM demodulation; extracting a pilot symbol from the demodulated data to realize channel equalization; extracting a diffusion symbol sequence; inverse two-dimensional fast Fourier transform is carried out; deblocking the data symbol blocks; and normalizing, demodulating and decoding the received data symbol sequence to obtain a received data stream. According to the invention, the bit error rate can be effectively reduced in the environment with ultralow signal-to-noise ratio, multipath depth fading and large Doppler frequency offset.

The present invention relates to a polyhedral single crystal alumina / aluminum nitride / epoxy resin thermal conductive composite material and a preparation method thereof, characterized in that: (1) 20 to 75 parts of polyhedral single crystal alumina powder with D50=18 to 22um, 5 to 30 parts of aluminum nitride powder with D50=2 to 4um, 2 to 8 parts of polyhedral single crystal alumina with D50=0.3 to 0.5um, and 10 to 50 parts of E51 epoxy resin are taken for standby; (2) the polyhedral single crystal alumina and aluminum nitride powder are subjected to dry modification; (3) the modified powder, curing agent and accelerator are added to a star mill for mixing; then added to a vacuum degassing machine for degassing; and then subjected to curing treatment. Advantages of the present invention: the use of a ternary particle size close stacking system not only realizes close stacking, but also constructs an efficient, continuous and wide heat conduction channel, reducing the interface thermal resistance; the thermal conductivity of the epoxy resin composite material obtained is 3.0 to 6.0 W / mK, and has good insulation and mechanical properties.

The invention provides an aluminum-based carbon film photo-thermal evaporator and a preparation method and application thereof.The preparation method specifically comprises the following steps that laser etching is conducted on the surface of an Al sheet, an AL sheet with a periodic groove-shaped structure on the surface is obtained, and a product 1 is obtained; dropwise adding a furfural oxalic acid solution into the periodic groove-shaped structure on the surface of the product 1, and obtaining a product 2 when a uniform liquid film is formed on the periodic groove-shaped structure on the surface of the product 1; carrying out prepolymerization and carbonization treatment on the product 2 to obtain a product 3; the photothermal conversion efficiency and the evaporation rate of the aluminum-based carbon film photothermal evaporator are remarkably improved, a concentrated saline water drainage mode is further combined, and by means of the concentrated saline water drainage mode, the evaporation rate of the aluminum-based carbon film photothermal evaporator is improved. And the high-performance interface solar evaporation system which has excellent salt resistance and keeps stable and efficient operation in the long-term evaporation process is obtained.

The invention provides a preparation method of an ethylene epoxidation Ag / SiC catalyst, which comprises the following steps: step 1, treating SiC powder with acid, and then treating the SiC powder with alkali to obtain a SiC precursor; step 2, mixing the SiC precursor, a pore-forming agent and an auxiliary agent, molding, and carrying out heat treatment to obtain a SiC molded carrier; step 3, loading a silver precursor on the SiC molding carrier to obtain an ethylene epoxidation Ag / SiC catalyst; wherein the acid comprises fluorine-containing acid and at least one inorganic acid except the fluorine-containing acid, and the alkali is an amine compound. The silicon carbide is subjected to acid erosion treatment, so that the surface roughness of the silicon carbide can be improved, the loaded metal particles are fixed on the surface of the SiC carrier, migration and agglomeration of active component Ag ions in the reaction process are reduced, and the stability of the Ag / SiC catalyst is improved.