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52 results about "Periodic composites" patented technology
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Simple implementation method for performing gradual homogenized prediction on thermal expansion coefficient of periodic composite material
InactiveCN105160085AImproved coefficient of thermal expansionImprove adaptabilitySpecial data processing applicationsReaction fieldElement model
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.
Owner:DALIAN UNIV OF TECH
Method for preparing controlled degradation metal composite coating on surface of medical magnesium alloy
InactiveCN104178765ATightly boundAccurate and controllable degradation rateLiquid surface applicatorsMolten spray coatingChemical vapor depositionTotal thickness
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.
Owner:HUAIYIN INSTITUTE OF TECHNOLOGY
Cutting tool composite coating and preparing method thereof
ActiveCN110373639AHigh hardnessBreak consistencyVacuum evaporation coatingSputtering coatingFilm baseHardness
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.
Owner:ARISON SURFACE TECH SUZHOU
Periodic composite repair device of arsenic polluted soil
InactiveCN104368591AClosely arrangedAdjust PH in real timeContaminated soil reclamationArsenic pollutionSoil restoration
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.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Periodic composite repair method of arsenic polluted soil
ActiveCN104368592AClosely arrangedAdjust PH in real timeContaminated soil reclamationArsenic pollutionAutomatic control
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.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Flexible ablation resistor thin film and preparation method thereof
ActiveCN108106748AAvoid singleAvoid bufferingThermometers using electric/magnetic elementsVacuum evaporation coatingElectrical resistance and conductanceInterference resistance
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.
Owner:48TH RES INST OF CHINA ELECTRONICS TECH GROUP CORP
Solid state laser
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.
Owner:SHANGHAI JIAO TONG UNIV
Periodic composite material elastic constitutive parameter prediction method and device and storage medium
PendingCN114707276ABuild accuratelyImprove computing efficiencyGeometric CADIncreasing energy efficiencyVoxelCoarse mesh
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.
Owner:JIHUA LAB
A cluster of supercells capable of forming line defect periodic composite structure
PendingCN111833835AAvoid spreadingTo achieve the purpose of vibration reductionSound producing devicesEngineeringSound wave
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.
Owner:SOUTHEAST UNIV
Sintered neodymium iron boron magnet surface functional film and preparation method thereof
InactiveCN111118465AImprove high temperature resistance and oxidation resistanceHigh hardnessVacuum evaporation coatingSputtering coatingCrazingFilm base
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.
Owner:SHENYANG GENERAL MAGNETIC
Full-paving periodic cushion layer vibration reduction ballast bed
InactiveCN112626932AIncreasing the thicknessIncreased impedance ratioBallastwayRelative displacementClassical mechanics
Owner:CHINA RAILWAY DESIGN GRP CO LTD
Supercell capable of forming composite structure with multiple band gap periods
PendingCN111833834ATo achieve the purpose of vibration reduction and noise reductionSmall sizeSound producing devicesEngineeringSound wave
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.
Owner:SOUTHEAST UNIV
A low-loss on-chip transmission line based on an aperiodic composite left-handed-right-handed structure
The application discloses a kind of low-loss on-chip transmission lines based on non-periodic composite left-right hand structure, it is related to radio frequency integrated circuit design technical field, including first radio frequency port, second radio frequency port, M series resonance unit and N parallel resonance unit, each series resonance unit includes series right-hand inductance, left-hand capacitance, each parallel resonance unit includes parallel left-hand inductance, right-hand capacitance;M series resonance unit is in turn connected in series, one end of N parallel resonance unit is in turn loaded between two series resonance units, and the other end of parallel resonance unit is grounded, first radio frequency port is loaded in the free end of first series resonance unit, and second radio frequency port is loaded in the free end of M series resonance unit.The application uses non-periodic lumped transmission line to avoid too large size;While maintaining low loss, echo loss in broadband is all better than 20dB.
Owner:NANJING UNIV OF POSTS & TELECOMM
Plasmon waveguide structure and refractive index sensor
PendingCN121703986APhase-affecting property measurementsOptical waveguide light guideResonant cavityRefractive index
The embodiment of the invention provides a plasmon waveguide structure and a refractive index sensor, and the plasmon waveguide structure comprises a metal substrate layer; a multi-period composite metal grating layer; the dielectric layer is arranged between the metal substrate layer and the multi-period composite metal grating layer; wherein the multi-period composite metal grating layer is composed of nano-metal supercell structures which are periodically arranged in the direction, and each nano-metal supercell structure is formed by periodically arranging at least two metal structures with different grating periods in the direction according to a preset grating interval; and the structures are alternately arranged in the direction at preset periodic intervals. According to the invention, decoupling and flexible regulation and control of resonance position and intensity can be realized based on a plurality of independent resonant cavities with spatial separation provided by the multi-period composite metal grating layer.
Owner:XINJIANG HOTAN UNIVERSITY
A Simple Realization Method for Predicting Thermal Conductivity of Periodic Composites by Progressive Homogenization
InactiveCN105574255BHigh barriers to useEasy to implementDesign optimisation/simulationSpecial data processing applicationsElement modelFinite element software
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.
Owner:DALIAN UNIV OF TECH
Elastomer material, composite damping base plate thereof and preparation method of base plate
PendingCN114213776AImprove aging resistanceImprove mechanical propertiesRail fastenersPolyurethane elastomerPolymer science
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.
Owner:GUANGDONG SUNLITE MATERIAL SCI & TECH
A point-laid period cushion vibration-reducing ballast bed
The invention provides a spot-laid periodic cushion vibration-reducing track bed, which includes a periodic compound track bed slab and a concrete base arranged below it, and the space between the periodic compound track bed slab and the concrete base is limited by a limiting structure to prevent Relative displacement, wherein, the periodic composite track bed slab is formed by alternately arranging and consolidating concrete slabs and periodic cushions from top to bottom, and the projections of the concrete slabs in the vertical direction are completely coincident; each concrete slab is adjacent to its lower The periodic cushion layer constitutes a basic unit, and the number of periodic repetitions of the basic unit along the vertical direction is not less than 2; the periodic cushion layer is discretely distributed according to the law along the driving direction by a square cushion plate. The vibration-damping ballast bed forms elastic wave forbidden bands in the vertical direction, transverse direction and longitudinal direction, which can effectively control the propagation of vibration in three directions, and can actively adjust the forbidden band range by changing the structural geometric size and material composition, and has strong adjustability.
Owner:CHINA RAILWAY DESIGN GRP CO LTD
A soft-hard composite nano-multilayer coating tool and its preparation method
ActiveCN108456845BHigh hardnessExtend your lifeVacuum evaporation coatingSputtering coatingAlloyCutting force
Owner:XIAMEN UNIV
LED epitaxial wafer structure for improving luminous efficiency
The application discloses an LED epitaxial wafer structure for improving light emitting efficiency, which comprises a substrate, an AlN buffer layer, an undoped GaN layer, an n-type GaN layer doped with Si, a multi-quantum well layer, an AlGaN electron blocking layer and a P-type GaN layer in sequence, wherein the multi-quantum well layer comprises 9-14 periodic composite structures of InGaN well layer / GaN barrier layer / InN layer, the InN layer is used for compensating In component of a quantum well interface, improving crystal quality of a well-barrier interface in the quantum well, Si is doped in the GaN barrier layer, the Si doping concentration in each GaN barrier layer is 0.8-0.9 times of the Si doping concentration in the previous GaN barrier layer, the Si doping concentration in the GaN barrier layer is gradually reduced, the electron transverse expansion capability is improved, and the electron and hole recombination efficiency in the quantum well is improved. The application can effectively improve the light emitting efficiency of the LED.
Owner:XIANGNENG HUALEI OPTOELECTRONICS
A high-temperature alloy cutting coating tool
The present invention discloses a high-temperature alloy cutting coating tool and a preparation method thereof, comprising a tool substrate and a multi-layer coating deposited on the substrate, wherein the multi-layer coating sequentially comprises a transition layer, a periodic composite layer and a functional layer from the substrate side toward the surface side of the multi-layer coating, wherein the periodic composite layer has an alternating stacking structure consisting of a first composite layer and a second composite layer alternately repeated twice or more. The transition layer has the same chemical composition as the first composite layer and is composed of Ti a Al b Cr c The second composite layer has the same chemical composition as the functional layer and is composed of Ti d Al e Cr f M g L h The present invention provides a high-temperature alloy cutting coating tool with high wear resistance, crack resistance, high temperature resistance and oxidation resistance, high bonding strength between the coating and the substrate, simple production process and low production cost.
Owner:WUXI GUOHONG MEASURING & CUTTING TOOLS
Unit cell structure made of three-dimensional periodic composite material
PendingCN111369963AGuaranteed machining accuracyExtended service lifeSound producing devicesEngineeringStructural engineering
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.
Owner:SOUTHEAST UNIV
Three-dimensional metamaterial, unit structure, preparation method and equipment
The invention discloses a three-dimensional metamaterial unit structure. The structure sequentially comprises an electromagnetic loss three-dimensional superstructure, a first dielectric structure layer, an electromagnetic loss metasurface, a second dielectric structure layer and a lossless band-pass superstructure which are attached to one another. The electromagnetic loss three-dimensional superstructure is provided with a hollow enclosure table structure, the enclosure table is in a square enclosure table shape, and the section of the enclosure table on one side is in a convex shape. The electromagnetic loss metasurface is provided with a substrate, a periodic composite ring structure is prepared on the substrate, the composite ring structure comprises an outer-circle square ring and an inner-circle regular octagonal ring, the composite ring is made of any one or any combination of gold, silver or copper metal, and the substrate of the electromagnetic loss metasurface is made of any one of a PI film, a PEN film, an FR4 plate or an F4B plate.
Owner:SHANGHAI UNIV OF ENG SCI
A method for anti-seizure of ti alloy workpiece
ActiveCN108611590BHigh purityGood film base binding performanceVacuum evaporation coatingSputtering coatingFrettingIon beam
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.
Owner:中核同创(成都)科技有限公司
Point laying periodic cushion layer vibration reduction ballast bed
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.
Owner:CHINA RAILWAY DESIGN GRP CO LTD
An ultraviolet light-emitting diode epitaxial structure, an ultraviolet light-emitting diode, and an electronic device
An embodiment of the present invention provides an ultraviolet light-emitting diode epitaxial structure, an ultraviolet light-emitting diode, and an electronic device. The epitaxial structure includes a substrate, a first AlN layer, a multi-period composite regulation 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 blocking layer, and a p-type GaN layer, which are grown in sequence from bottom to top. The multi-period composite regulation layer includes multiple periodic structures grown in sequence from bottom to top. Each periodic structure includes 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. Among them, the 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. By growing a multi-period composite regulation layer between the first AlN layer and the n-type Al x Ga 1‑x N contact layer, the present invention reduces the lattice mismatch between the first AlN layer and the n-type Al x Ga 1‑x N contact layer, regulates the warping of the ultraviolet light-emitting diode epitaxial wafer, filters the dislocations extending upward from the first AlN layer, reduces the compressive stress of the n-type Al x Ga 1‑x N contact layer, improves the crystal quality, and enhances the light-emitting efficiency of the device.
Owner:GEN SEMICONDUCTOR (ANHUI) CO LTD
A Low-frequency and Wide-frequency Vibration Suppression Structure Based on Double-period Bandgap Characteristics
ActiveCN108119588BSolve the problem of poor low-frequency vibration suppression effectSuppress vibration responseShock absorbersAviationNoise control
The invention relates to a low-frequency broadband vibration suppression structure based on double-period forbidden band characteristics, which belongs to the field of mechanical vibration and noise control, especially the technical field of aviation, aerospace and ship vibration and noise control. The vibration suppression structure is composed of periodic composites of the same cells, in which a single cell contains a four-layer structure, from bottom to top, a homogeneous attachment layer, a periodic sandwich layer, a homogeneous constraint layer and a homogeneous surface layer. The periodic sandwich layer of a single cell of the structure is composed of two materials, A and B. Through holes are respectively opened in the centers of the sandwich layers composed of A material and B material, and a local resonance is installed in each through hole. The unit and local resonance unit are composed of two upper and lower spring elements connected to a mass element in the middle. The two spring elements are respectively connected to the homogeneous attachment layer on the lower side and the homogeneous constraint layer on the upper side. The periodic vibration suppression structure provided by the present invention can produce a vibration suppression effect in a low frequency and wide frequency range, and helps to solve the problem of poor low frequency vibration suppression effect of existing vibration suppression technology.
Owner:NORTHWESTERN POLYTECHNICAL UNIV
A flexible ablation resistance film and its preparation method
ActiveCN108106748BReduce thermal stressReliable growthThermometers using electric/magnetic elementsVacuum evaporation coatingProtection layerMechanical engineering
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.
Owner:48TH RES INST OF CHINA ELECTRONICS TECH GROUP CORP
Composite coating of cutter for efficient cutting of aerospace titanium alloy and preparation method of composite coating
The invention discloses a composite coating of a cutter for efficient cutting of aerospace titanium alloy and a preparation method of the composite coating. The composite coating sequentially comprises a transition layer, a periodic composite layer and a functional layer from the base body side of the cutter to the surface side of the coating, the wear resistance, the high temperature resistance and the oxidation resistance of the tool in the titanium alloy cutting process are improved, the bonding strength of the coating and the matrix is enhanced, the preparation technology is simplified, the cost is reduced, the service life of the tool is prolonged, the machining efficiency of the tool is improved, and the machining cost is reduced.
Owner:江苏麦合新材料科技有限公司
solid state laser
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.
Owner:SHANGHAI JIAO TONG UNIV
Novel phonon crystal deceleration pavement structure
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.
Owner:TONGJI UNIV