32 results about "Periodic composites" patented technology

The present invention discloses a simple implementation method for performing gradual homogenized prediction on a thermal expansion coefficient of a periodic composite material. The method comprises the following steps: establishing a single-cell finite element model by means of commercial finite element software, and setting a material parameter in the single-cell finite element model; performing finite element grid division on the single-cell finite element model to obtain nodes and unit information of the single-cell finite element model; determining an initial displacement field according to node coordinate values of the single-cell finite element model; calculating a periodic structure equivalent elastic modulus and a periodic structure equivalent thermoelastic constant; and calculating a thermal expansion coefficient of a periodic composite material. The simple implementation method for performing gradual homogenized prediction on the thermal expansion coefficient of the periodic composite material disclosed by the present invention is convenient to execute, and the method is capable of using the conventional commercial finite element software as a black box to predict the thermal expansion coefficient of the periodic composite material, so that adaptability of a homogenization method is greatly improved; and a process of resolving a strain field in original homogenization and performing integration on each unit is converted to a product of a corresponding displacement field and a node reaction field, which can be obtained in the commercial finite element software, and the process is simplified.

The invention discloses a method for preparing a controlled degradation metal composite coating on the surface of a medical magnesium alloy. The method comprises the following steps: deoiling, grinding and polishing the surface of the magnesium alloy, and depositing a magnesium (Mg) / iron (Fe) periodic composite multilayer film on the surface of the magnesium alloy material through physical vapor deposition, chemical vapor deposition, cold spraying or plasma spraying, wherein the periodicity of magnesium and iron is 2-20, a thickness ratio (blending ratio) of magnesium to iron is 1:(0.1-10), and the total thickness of the coating is 100nm-1000mu m. According to the metal composite coating, the corrosion rate of a magnesium alloy base material can be effectively relieved, good relevance is formed between the corrosion and degradation speed of the magnesium alloy and the periodicity, blending ratio and total thickness of the coating; the composite coating has the characteristics of high biological activity and controllable degradation speed, and the problem that the magnesium alloy is extremely short in implant time in a human body is solved.

The invention discloses a cutting tool composite coating. A functional layer of the cutting tool composite coating comprises a TiAlN single layer, a TiAlN / TiSiN nano composite layer, a TiSiN single layer and a TiAlN / TiSiN nano composite layer; the TiAlN / TiSiN nano composite layer, the TiSiN single layer and the TiAlN / TiSiN nano composite layer are sequentially deposited on the surface of the TiAlNsingle layer; and the functional layer is a composite coating containing a plurality of cycle periods. By means of the cutting tool composite coating and a preparing method of the cutting tool composite coating, the cutting tool composite coating is of a periodic composite structure; on the premise of high hardness, the good film-based adhesion effect is achieved, and the cutting tool composite coating and the preparing method can be used for processing die steel, high-speed steel, high-temperature alloy steel or even hardened steel.

The invention belongs to the technical field of soil restoration, and in particular relates to a periodic composite repair device of arsenic polluted soil, the periodic composite repair device includes an electric field generating module, a vegetation restoration layer, a soil PH regulating module and a surfactant spraying module, the electric field generating module includes a power supply and an anode chamber and a cathode chamber, the anode chamber and the cathode chamber are arranged under the ground; the vegetation restoration layer is arranged on the surface layer of a to-be-repaired soil region, the restoration vegetation is ciliate desert-grass, the soil PH regulating module sprays a PH adjusting solution to the anode chamber, the cathode chamber and the to-be-repaired soil region, and the surfactant spraying module sprays a surfactant to the surfactant spraying module. Every steps are closely linked, by the manner of determination of periodic circulation on the basis of the detection value, unnecessary time and cost waste can be avoided, soil and electrode chamber PH can be regulated in real time, the ratio of an acid and alkali liquid tank can be regulated by an automatic control device, the stability is high, arsenic is repaired completely, and finally more than 98% of the arsenic can be repaired.

The invention belongs to the technical field of soil restoration, and in particular relates to a periodic composite repair method of arsenic polluted soil, the periodic composite repair method includes the following steps: ciliate desert-grass is transplanted for preparation and formation of a repair layer, meanwhile the soil is electrochemically repaired, after one period of the repair, the ciliate desert-grass is harvested for testing, and completed repair or re electrochemical repair or the natural repair is determined according to the test results. Every steps in the method are closely linked, by the manner of determination of periodic circulation on the basis of the detection value, unnecessary time and cost waste can be avoided, repair equipment arrangement is compact, soil and electrode chamber PH can be regulated in real time, the ratio of an acid and alkali liquid tank can be regulated by an automatic control device, the stability is high, flexibility is strong, according to the testing results, periodic circulation manner is changed, arsenic is repaired completely, and finally more than 98% of the arsenic can be repaired.

The invention discloses a flexible ablation resistor thin film and a preparation method thereof. The flexible ablation resistor thin film comprises a flexible substrate and an ablation resistor thin film, wherein a composite transition layer is arranged therebetween, and the composite transition layer comprises a periodic composite film formed by alternately depositing Si3N4 layers, AlN layers andAl2O3 layers. The preparation method comprises the steps of preparing the composite transition layer and preparing the ablation resistor thin film. The flexible ablation resistor thin film has the advantages of high environmental interference resistance, high reliability level and the like. The preparation method of the flexible ablation resistor thin film has the advantages of simple preparationprocess, high environmental adaptability, good reliability and the like. The flexible ablation resistor thin film can be used in a heatproof protection layer of spacecrafts such as a hypersonic aircraft, a solid rocket engine and the like, can realize ablation volume measurement in harsh environments such as high temperature and high heat flow scouring, and is of great significance to improving the application reliability of spacecrafts such as a hypersonic aircraft, a solid rocket engine and the like.

A solid state laser comprises a pumping source, a pumping tail fiber, and a first coupling lens, a second coupling lens, a pumping-end cavity lens, a laser gain medium and an output cavity lens arranged in the pumping laser output direction of the pumping tail fiber successively, the upper and lower end surfaces of the laser gain medium include upper and lower heat sinks respectively, and the pumping-end cavity lens, the output cavity lens and the laser gain medium form a laser resonator. The solid state laser is characterized in that the laser gain medium is a periodic composite gain medium which is formed by slice-shaped laser crystals in the micron level thickness and slice high-thermal-conductivity materials in the in the micron level thickness by high-temperature bonding. The solid state laser can realize laser output of high power, high beam quality and high polarization degree.

The invention discloses a periodic composite material elastic constitutive parameter prediction method and device and a storage medium, and the method comprises the steps: obtaining geometric data of a target representative unit of a periodic composite material, the target representative unit being composed of a first phase material and a second phase material; based on the geometric data, a double-layer voxelization grid model corresponding to the target representative unit is established, and the double-layer voxelization grid model comprises a coarse grid model and a fine grid model; determining a boundary voxel corresponding to the junction of the first phase material and the second phase material in the coarse mesh model according to the respective spatial ranges of the first phase material and the second phase material in the target representative unit; reconstructing boundary voxels in the coarse mesh model according to the fine mesh model; and performing finite element analysis on the new coarse mesh model obtained after subdivision to obtain the elastic constitutive parameters of the periodic composite material. The technical problem of low prediction efficiency of the elastic constitutive parameters of the periodic composite material in the prior art is solved.

The invention relates to a cluster of supercells capable of forming a line defect periodic composite structure. The cluster of supercells comprises eight types of A-H. Each kind of supercell element comprises a substrate (1) and scatterer oscillators (2) arranged on the substrate (1) according to a quasi-periodic arrangement; through mutual combination of the supercell elements, a periodic composite structure with a line defect characteristic can be formed. The periodic composite structure has a band gap characteristic, and vibration in a specific frequency range cannot be propagated through the structure. The introduction of the defect structure changes the original energy band structure of the periodic composite structure, so that the elastic wave with the frequency corresponding to thedefect state can only be propagated along the line defect. Therefore, the periodic composite structure with the line defect characteristic provides an effective way for controlling elastic waves by utilizing an artificial structure, and has important value in the fields of engineering vibration isolation, waveguides, sound wave filters and the like.

The invention discloses a sintered neodymium iron boron magnet surface functional film and a preparation method thereof. The method comprises the steps including using of a magnet pretreatment process, magnet deposition pretreatment and preparation of the functional film by adopting a physical vapor deposition method. The functional film is a multiperiodic composite film with an Al2O3 layer and aTiN layer serving as one period, and meanwhile, the functional film has the hardness above 15 GPa and good corrosion protection performance and oxidation resistance. At the same time, by depositing the Al2O3 layer and the TiN layer alternately, microstructure defects such as pin-holes, through holes and micro-cracks penetrating a single-layer film are prevented from being formed, and the defect that the thickness of the traditional single-layer film is hard to control is well solved; and moreover, the high temperature oxidation resistance of a magnet is enhanced by adding Al2O3. By adopting the form of combined double-layer film alternating deposition and multiple periods, internal stress of the film is reduced, and the film based adhesive force is enhanced. By depositing the functional film on a neodymium iron boron surface, the application fields of neodymium iron boron in high humidity and heat environments and acid and alkali environments are expanded.

The invention relates to a supercell capable of forming a composite structure with multiple band gap periods. The supercell comprises a substrate (1) and scatterer oscillators (2) periodically arranged on the substrate. The scatterer oscillators (2) are divided into embedded oscillators (2-1) and convex oscillators (2-2). And the convex vibrators (2-2) are divided into convex vibrators A (2-2-1) and convex vibrators B (2-2-2). The periodic composite structure formed by the supercell elements has multiple band gaps, and can play a role in inhibiting propagation of elastic waves or sound waves in multiple frequency ranges. Therefore, the integrated design of the structure and the vibration isolation system is achieved, and the supercell has the advantages of being light in weight, wide in vibration isolation frequency, high in reliability and the like and has wide application prospects in the engineering vibration isolation field.

The invention discloses a simple implementation method for predicting the periodical composite material thermal conductivity coefficient in a gradual and homogeneous manner. A unit cell finite element model is established through commercial finite element software; the material thermal conductivity coefficient of the unit cell finite element model is set; the unit cell finite element model is subjected to finite element mesh dividing to obtain node and unit information of the unit cell finite element model; an initial temperature field is determined according to node coordinate values of the unit cell finite element model; and the periodical composite material thermal conductivity coefficient is calculated. According to the simple implementation method, the performance predication for any complex periodical structure can be realized by the unit type and any combination provided by the commercial finite element software; an integration operation is required for each unit when a right end load of a temperature gradient field control equation is solved by the original homogenization method; the original homogenization method, different from a conventional finite element format, can be realized by requiring corresponding programming, so that the original homogenization method is relatively high in threshold in use; however, the simple implementation method provided by the invention enables the homogenization method to perform direct calculation through the existing commercial finite element software, so that the difficulty in use is greatly lowered.

The invention relates to the technical field of vibration reduction, in particular to an elastomer material, a composite vibration reduction base plate of the elastomer material and a preparation method of the base plate. The elastomer material comprises two materials, an active agent hydroxyl-terminated polybutadiene is added into a damping rubber component, and double bonds of the active agent hydroxyl-terminated polybutadiene can participate in vulcanization reaction of rubber; the terminal hydroxyl group can participate in the cross-linking reaction of the polyurethane elastomer, so that chemical interface bonding is formed between the two elastomers, and the use stability of the prepared periodic composite base plate is kept; according to the preparation scheme of the composite vibration reduction base plate, the inelastic layer and the elastomer are compounded through a secondary rotary mold vulcanization process, and the prepared composite vibration reduction base plate is stable in structure and good in vibration reduction performance; the composite vibration reduction base plate is of the multi-layer periodic structure formed by compounding the elastic layer and the non-elastic layer, and the high vibration reduction characteristic of low height is achieved through the vibration reduction characteristic of the periodic structure by means of the composite vibration reduction base plate with the periodic structure.

The invention provides a unit cell structure made of a three-dimensional periodic composite material. The unit cell structure is characterized by comprising a unit cell base body and a three-dimensional entities, the unit cell base body is cubic, and a body center cavity is formed in the body center of the unit cell base body; the three-dimensional entities are evenly distributed in the unit cellbase body with the body center cavity as the circle center and are cavities formed by rotating ellipsoids or any two-dimensional graph around any axis of the ellipsoids or any two-dimensional graph, and the three-dimensional entities are filled with scatterers. The invention provides a unit cell structure made of the three-dimensional periodic composite material, which can generate elastic wave forbidden bands in x, y and z directions of a Cartesian coordinate system, so that the unit cell structure can be used for manufacturing vibration and noise reduction artificial materials.

The invention belongs to the technical field of surface treatment of low temperature plasma materials, and particularly relates to a method for preventing seizure of Ti alloy workpieces. The method comprises nine steps. The method realizes a preparation process of Ti-TiN periodic composite coating by Ti alloy workpiece baking degassing, ion beam sputtering cleaning and in-situ ion beam assisted magnetron sputtering deposition to obtain the uniform and compact Ti-TiN periodic composite coating with good bonding performance. The method has the advantage of improving the characteristics such as the wear resistance, fatigue resistance and fretting wear of the workpieces to meet the requirements of anti-seizure and wear resistance. The Ti-TiN periodic composite coating prepared on an inner threaded surface of a Ti alloy fastener has the advantages of high purity, good film-based bonding performance, uniform and dense film layers, and no porosity at the interface. The treated Ti alloy fastener meets the requirements of wear resistance, anti-seizure, anti-fretting wear and the like, has at least 2 times higher anti-seizure performance than untreated workpieces, meets the use requirementsof a certain type of equipment, greatly reduces the cost, and improves the overall use stability and the service life of the equipment.

The invention provides a point laying periodic cushion layer vibration reduction ballast bed which comprises a periodic composite ballast bed plate and a concrete base arranged below the periodic composite ballast bed plate, the periodic composite ballast bed plate and the concrete base are limited through a limiting structure, and relative displacement is prevented. The periodic composite roadbed bed plate is formed by alternately arranging and solidifying concrete slabs and periodic cushion layers from top to bottom, and the projections of the concrete slabs in the vertical direction completely coincide. Each concrete slab and the adjacent periodic cushion layer below the concrete slab form a basic unit, and the number of periodic repetitions of the basic units in the vertical direction is not less than 2; and the periodic cushion layer is formed by regularly and discretely distributing square cushion plates along the driving direction. Elastic wave forbidden bands are formed in the vertical direction, the transverse direction and the longitudinal direction of the vibration reduction ballast bed, propagation of vibration in the three directions can be effectively controlled, the forbidden band range can be actively adjusted by changing the geometric dimension of the structure and material composition, and adjustability is high.

A solid state laser comprises a pumping source, a pumping tail fiber, and a first coupling lens, a second coupling lens, a pumping-end cavity lens, a laser gain medium and an output cavity lens arranged in the pumping laser output direction of the pumping tail fiber successively, the upper and lower end surfaces of the laser gain medium include upper and lower heat sinks respectively, and the pumping-end cavity lens, the output cavity lens and the laser gain medium form a laser resonator. The solid state laser is characterized in that the laser gain medium is a periodic composite gain medium which is formed by slice-shaped laser crystals in the micron level thickness and slice high-thermal-conductivity materials in the in the micron level thickness by high-temperature bonding. The solid state laser can realize laser output of high power, high beam quality and high polarization degree.

The invention relates to a novel phonon crystal deceleration pavement structure. The novel phonon crystal deceleration pavement structure is formed by sequentially overlapping five base plates and four phonon crystal thin plates, wherein the base plates are solid rubber plates, and vehicles can stably run on the base plates, the phonon crystal thin plates are rubber plates, and cylindrical small holes are regularly distributed to serve as scatterers so as to form a periodic distribution energy band structure of elastic constants and density. The base plates and the phonon crystal thin plates are sequentially overlaid to form the composite elastic wave phonon crystal structure with periodically modulated body elastic modulus and mass density. Compared with the prior art, a three-dimensional photon crystal periodic composite structure is adopted, and energy dissipation and speed reduction effects on vehicles can be achieved based on periodic Bragg scattering and local monomer Mie scattering.

The invention discloses a strip-laying periodic cushion layer vibration reduction ballast bed which comprises a periodic composite ballast bed plate and a concrete base arranged below the periodic composite ballast bed plate, and the periodic composite ballast bed plate is formed by alternately arranging and solidifying concrete plates and periodic cushion layers from top to bottom; the periodic cushion layer is composed of at least one long-strip-shaped cushion plate which continuously extends in the driving direction, the width of the cushion plate is smaller than that of a concrete plate, the cushion plate laying range of the cushion layer in the same period does not exceed the concrete plate, and a cushion layer strip laying mode is formed. Projections of the periodic cushion layers located in the interlayers are completely overlapped, the periodic cushion layers of the adjacent layers are aligned in the vertical direction or arranged in a staggered mode in the transverse direction, and a one-dimensional or two-dimensional scattering type periodic structure is formed. The vibration reduction ballast bed can form elastic wave forbidden bands in the vertical direction and the transverse direction, vertical vibration propagation and transverse vibration propagation are effectively controlled, the forbidden band range can be actively adjusted by changing the geometric dimension and material composition of the structure, and adjustability is high.

The invention relates to a method for calculating equivalent thermal conductivity coefficients of hollow glass beads. The method comprises the following steps: step 1, embedding the hollow glass beadsand equivalent solid spheres thereof in a virtual matrix material, and establishing two periodic composite material systems 1 and 2; step 2, establishing representative material units 1 and 2 in theperiodic composite material systems 1 and 2; step 3, applying different temperature boundary conditions to two opposite surfaces of the composite material units 1 and 2; step 4, calculating the equivalent thermal conductivity coefficient of the composite material unit 1; step 5, drawing the equivalent thermal conductivity coefficient changing curve of the corresponding composite material unit 2; and step 6, using the intersection between the equivalent thermal conductivity coefficient of the composite material unit 1 and the equivalent thermal conductivity coefficient changing curve of the composite material unit 2 as the equivalent thermal conductivity coefficients of hollow glass beads. The method has the advantages of being simple in principle, convenient to use, and high in calculatingprecision.

The embodiment of the invention provides an ultraviolet light-emitting diode epitaxial structure, an ultraviolet light-emitting diode and electronic equipment. The epitaxial structure comprises a substrate, a first AlN layer, a multi-cycle composite regulation and control layer, an n-type Al < x > Ga < 1-x > N contact layer, a multi-quantum well light-emitting layer, a p-type Al < y > Ga < 1-y > N barrier layer and a p-type GaN layer which are sequentially grown from bottom to top, and the multi-cycle composite regulation and control layer comprises a plurality of cycle structures which are sequentially grown from bottom to top, each periodic structure comprises a second AlN layer, an Al < m > Ga < 1-m > N layer, an Al < n > Ga < 1-n > N layer and an Al < k > Ga < 1-k > N layer which are sequentially grown from bottom to top, and Al components in the n-type Al < x > Ga < 1-x > N contact layer, the Al < m > Ga < 1-m > N layer, the Al < n > Ga < 1-n > N layer and the Al < k > Ga < 1-k > N layer are different. According to the ultraviolet light-emitting diode epitaxial wafer, the multi-cycle composite regulation and control layer is grown between the first AlN layer and the n-type AlxGa1-xN contact layer, so that lattice mismatch between the first AlN layer and the n-type AlxGa1-xN contact layer is reduced, warping of the ultraviolet light-emitting diode epitaxial wafer is regulated and controlled, dislocation of upward extension of the first AlN layer is filtered, pressure stress of the n-type AlxGa1-xN contact layer is reduced, crystal quality is improved, and light-emitting efficiency of a device is improved.

The invention belongs to the field of composite material early-stage damage detection, and particularly relates to a periodic composite material early-stage damage second harmonic detection method, which comprises the following steps: S1, composite material parameter acquisition: the specific parameters comprise composite material change distribution period wavelength and thickness h; s2, fundamental wave parameters are determined, and corresponding fundamental wave frequencies are selected according to the composite material parameters; the change distribution period wavelength of the composite material is the same as the cumulative change period distance Ln of the second harmonic excited by the corresponding frequency in the flat plate with the same thickness; s3, flaw detection; s4, performing damage analysis. According to the scheme, the limitation of the traditional secondary harmonic detection phase velocity matching condition is broken through, the detected fundamental frequency is selected according to the period of the composite material, the secondary harmonic can be continuously accumulated without attenuation, and a reliable technical scheme is provided for early damage secondary harmonic detection of the composite material in which two materials are periodically distributed.

The invention relates to the technical field of semiconductor photoetching, and particularly relates to a patterned sapphire substrate, a preparation method thereof and an LED epitaxial wafer. The patterned sapphire substrate comprises a substrate body and a periodic composite structure protruding out of the upper surface of the substrate body. The composite structure comprises a cone and a plurality of microstructures protruding out of or recessed into the conical surface of the cone. The cross sectional area of the microstructure is gradually reduced from the bottom to the top, and the microstructure intersects with the vertex of the cone at the top. The patterned sapphire substrate is provided with regular gully patterns and edges and corners, on one hand, side growth is maximized, mismatch dislocation of epitaxial growth is effectively restrained, on the other hand, the light path of incident light is further changed, light scattering is effectively increased, the emergent probability of the light from the sapphire substrate is increased, and the light extraction efficiency is further improved.