65 results about "Porous microstructure" patented technology

The invention discloses a method for efficiently generating high-brightness gamma radiation, and belongs to the technical field of radiation. A relativistic electron beam is injected into the porous microstructure foam target material, and high-brightness gamma ray radiation is generated. According to the method, the used device is simple, only the single relativistic electron beam and the porous microstructure foam target material are needed to interact, compared with a traditional uniform-density solid material, the energy conversion efficiency in the interaction process of the electron beam and a substance can be remarkably improved, and the energy conversion efficiency can be remarkably improved through the effective constraint effect of a high-intensity magnetic field. And the problems of low energy conversion rate, low light source brightness, poor radiation directivity, complex device or difficulty in experiment implementation and the like of the existing high-energy gamma ray radiation source are solved.

The invention provides a dopamine hybrid ligand ZIF-8 / gelatin composite aerogel and a preparation method and application thereof, and belongs to the field of composite aerogel and preparation thereof.The growth rate of ZIF-8 nanocrystals is accurately controlled through dopamine hybrid coordination metal ions, stable ZIF-8-DA hybrid crystals are formed, and the stability of the aerogel is improved. The crystal not only solves the problem that the traditional MOF material is easy to aggregate particles, but also retains abundant chemical functional groups; furthermore, the ZIF-8-DA and a gelatin matrix are compounded by adopting a multi-crosslinking strategy and a freeze-thaw treatment technology to obtain the composite aerogel with a unique three-dimensional porous microstructure, so that the mechanical strength and the structural stability of the composite aerogel are remarkably improved, and the composite aerogel shows better heat-insulating and flame-retardant properties; the composite aerogel material prepared by the scheme has excellent heat insulation and flame retardant properties, and is suitable for high-energy-consumption fields such as building energy conservation, industrial heat management and environmental flame retardance.

The present invention aims to provide a graphene micro-nano cavity heat conduction film that allows the thickness thereof to ranging from 0.15 mm to 3 mm, achieving better thermal and electrical conductivity and causing rebound stress at 80% ≥ 0.05 MPa. The graphene micro-nano cavity heat conduction film prepared via the present invention has an areal density of 0.002 g / cm2 to 0.2 g / cm2, which ensures its applicability in pressure sensors, supercapacitors, fuel cells, carbon catalytic materials, switches, and optical modules. The graphene micro-nano cavity heat conduction film obtained via the present invention is made up of pure graphite, has a fluffy and porous microstructure, and has uniform and stable properties; additionally, during subsequent use, said film can be combined with other materials, has a wide application range, significant potential, and can be used in a variety of fields of application. The present invention is a material with high thermal and electrical conductivity, which is rare in the current market.

The invention relates to a passive radio frequency tactile sensor based on a ferroelectric composite material and a preparation method of the passive radio frequency tactile sensor, and belongs to the technical field of sensors. Comprising a multifunctional sensing unit used for non-contact dielectric sensing and contact type pressure sensing; wherein the multifunctional sensing unit comprises a first substrate layer, a first electrode layer, an elastic dielectric layer and a second electrode layer; the first electrode layer is arranged between the first substrate layer and the elastic dielectric layer; the sensing signal transmission unit comprises a second substrate layer and a communication coil; the communication coil is respectively connected with the first electrode layer and the second electrode layer; the communication coil is positioned on one side of the multifunctional sensing unit; wherein the second electrode layer is arranged between the elastic dielectric layer and the second substrate layer; at least one face of the elastic medium layer is of a porous microstructure. The pressure sensor not only has high-precision and high-sensitivity pressure sensing capability, but also shows excellent linear response characteristics, and effectively avoids a signal saturation phenomenon.

The invention discloses a stent with a super-lubricating coating as well as a preparation method and application of the stent, and belongs to the technical field of medical materials. The stent provided by the invention is composed of a stent base material and a super-lubricating coating, wherein the super-lubricating coating is composed of a base material pretreatment layer, a super-hydrophobic layer and a lubricating layer. The porous microstructure constructed on the surface of the stent base material is adjusted, and the compactness of the super-hydrophobic layer and the lubricating layer on the surface of the stent is controlled, so that the long-term and dynamic anti-fouling performance is realized, and the risk of adverse reactions such as infection, thrombosis and restenosis after the stent is implanted is reduced. The coating technology provided by the invention can be applied to various clinically common metal and plastic brackets, and has high clinical value.

The invention discloses a zinc ion battery gel electrolyte regulated and controlled by stress as well as a preparation method and application of the zinc ion battery gel electrolyte. The gel takes a high-molecular polymer network as a skeleton, and is prepared through layer-by-layer curing by adopting a photocuring 3D printing method. The gel is formed by stacking and arranging curing layers with the same height, and the electrolyte-electrode interface stress in the actual assembly process is controlled by a method for accurately regulating and controlling the curing layers. The stress regulates and controls nucleation, diffusion and dendritic crystal growth behaviors of interface zinc in the electroplating / stripping process and guides zinc to directionally and uniformly deposit, so that the compatibility and strength of an interface layer are optimized, meanwhile, a compact porous microstructure is beneficial to effective mass transfer of a gel interface and the interior, and the safety and cycle performance of the zinc ion battery are improved.

The application provides a wide stress full-linearity flexible ion-dissociation sensor and a preparation method thereof, which comprises a heat-shrinkable film material layer, a flexible AgNWs / MXene electrode, and a dielectric layer, the dielectric layer is attached between the two flexible AgNWs / MXene electrodes, and the two flexible AgNWs / MXene electrodes are provided with corresponding heat-shrinkable film material layers. The electrode of the application adopts the AgNWs / MXene composite electrode with good mechanical properties, the AgNWs microelectrode provides a conductive framework, and the MXene plays a role in protecting the AgNWs from oxidation and corrosion and providing a pseudo-capacitance; the application is based on the ion-dissociation effect of the ion gel film, uses the ion gel film with a porous microstructure as the dielectric layer, so that the dielectric layer has a larger deformable surface area and provides a larger deformation capacity, is thousands of times of the traditional solid-state similar sensor, and makes the ion-dissociation sensor have better linearity, higher sensitivity and faster response speed.

The invention discloses an empty pulp fiber material weft knitting fabric as well as a preparation method and application thereof, and relates to the field of garment fabrics. The hollow pulp fiber material weft knitting fabric is provided with at least one weave structure, and the weave structure is selected from at least one of twill two-position clothes, wicker ribs and single-face jacquard. The fabric comprises a weft knitting structure formed by weaving blended yarns of empty pulp fibers and cotton. The hollow pulp fiber has a porous microstructure, the cross section of the hollow pulp fiber is hollow and porous, and micropores are distributed on the surface of the longitudinal section of the hollow pulp fiber. The hollow pulp fiber material weft knitting fabric has a unique porous structure, the cross section of the hollow pulp fiber material weft knitting fabric is in a hollow porous shape, and micro-pores are distributed in the longitudinal section of the hollow pulp fiber material weft knitting fabric, so that the hollow pulp fiber material weft knitting fabric is a physical basis for achieving functional advantages of high specific surface area, high moisture regain, hollow heat storage and the like of the fabric, and is fundamentally different from common polyester or special-shaped polyester; the source guarantee is provided for the cooperation of multiple functions such as moisture absorption and sweat releasing, heat preservation and heat insulation.

The invention discloses a preparation method and application of a conjugated polymer PEDOT: PSS structure regulation membrane, and relates to a preparation method and application of an ultrafiltration membrane. The technical problem that an existing conductive polymer film is low in Pb < 2 + > rejection rate under the acidic condition is solved. The conjugated polymer PEDOT: PSS structure regulation membrane prepared by the invention is applied to interception of divalent lead ions in acidic wastewater. Acid treatment is used in the process of preparing the PEDOT: PSS film, so that PSS components are selectively removed, PEDOT is fiberized, the microstructure is looser, more wrinkled structures are presented on the whole, adsorption of Pb < 2 + > ions is more facilitated, meanwhile, after acid treatment, conjugate pi electrons are highly delocalized on a PEDOT chain which mainly plays a role in adsorption reduction, the electron transmission capacity is enhanced, and the Pb < 2 + > ion absorption efficiency is improved. More Pb < 2 + > is reduced, and finally, permeation of the membrane on water in acid wastewater and adsorption of metal ions are improved.

The invention discloses a LiCl-based flexible humidity sensor and a preparation method thereof, and belongs to the technical field of flexible sensors, and the preparation method comprises the following steps: mixing anhydrous lithium chloride and a polyimide solution according to a certain proportion, and stirring at normal temperature to form a mixed solution; uniformly coating a polyimide flexible substrate with the mixed solution, and drying the polyimide flexible substrate in a drying oven; and performing laser engraving on the surface of the dried film to form a laser-induced graphene interdigital electrode, thereby completing the manufacturing of the flexible humidity sensor. The flexible humidity sensing system adopts a novel nano composite material and a porous microstructure design, and can be tightly attached to the surfaces of objects in different shapes. The system is based on a capacitance change principle, can sensitively detect environment humidity change, and has good repeatability and stability. By optimizing the substrate material ratio and the electrode structure, accurate capture of weak signals such as respiratory airflow and skin surface humidity is realized.

The invention discloses a porous microstructure foaming white cement radiation refrigeration composite material and a preparation method thereof, and belongs to the technical field of building energy-saving materials.According to the material, sulphoaluminate white cement serves as a base material, a foaming agent is added, and evenly-distributed porous microstructures are formed in the preparation process; by utilizing the synergistic effect of the high reflection characteristic of the sulphoaluminate white cement and the enhanced scattering and heat insulation performance of the porous microstructure, the efficient radiation refrigeration function is realized; the problems that a traditional white cement material is low in radiation refrigeration efficiency and insufficient in heat insulation performance are solved, the preparation process is simple, the cost is controllable, the material can be widely applied to building exterior walls, roofs and other building envelopes, and remarkable energy-saving benefits and market application prospects are achieved.

The present invention discloses a fiber membrane that promotes the healing of infected wounds, a preparation method and an application thereof. The fiber membrane includes a plurality of non-randomly arranged spinning nanofibers, which are prepared by electrostatic spinning from a material including L-polylactic acid. The porous microstructure of the fiber membrane of the present invention provides a suitable microenvironment for cell migration and epithelial regeneration, and can promote the healing of bacterial-infected wounds. It has been verified that the fiber membrane of the present invention can effectively promote wound healing through antibacterial, relieving inflammation, collagen regeneration and angiogenesis. In addition, the present invention can maximize the antibacterial and tissue repair functions without adding external drugs through ultrasound enhanced treatment, and has broad application prospects.

The invention relates to the field of inorganic materials, in particular to a preparation method and application of antimony trioxide, an emulsifier, a water phase and mineral oil are mixed to obtain W / O emulsion, after the W / O emulsion is irradiated by ultraviolet light, an alcohol phase containing an organic antimony precursor is added, after stirring reaction, standing, centrifugation, sediment collection, washing and calcination are performed, and the antimony trioxide is obtained. The antimony trioxide prepared by the method provided by the invention has a special hollow porous microstructure structure, and is a very potential pseudocapacitor electrode material.

The invention relates to a preparation method of a hardness-adjustable microstructure antireflection film for a solar cell cover plate, and the method comprises the steps: S1, preparing a coating sol emulsion: mixing a precursor of a film forming material with an alcohol solvent, adjusting the pH value of a reaction system to be acidic or alkaline, and carrying out a first-stage stirring reaction; adjusting the reaction system to be slightly neutral or slightly acidic, adding a thermally-decomposable pore-forming emulsion and an emulsifier, carrying out a second-stage stirring reaction, and aging to obtain a coating sol emulsion; s2, coating and heat treatment: coating the surface of a glass substrate with the coating sol emulsion by adopting a roller coating method, and then carrying out heat treatment on the coated glass substrate; the heat treatment comprises preheating treatment for preliminarily curing the thin film and a tempering process for tempering the glass substrate and completely curing the thin film at the same time; in the tempering process, the pore-forming emulsion is pyrolyzed, and a porous microstructure is formed in the cured film. The hardness of the thin film can be effectively regulated and controlled, and the high anti-reflection effect is achieved through the microstructure.

The application relates to a kind of electrochemical oxidation synthesis ozone device and method based on patterning diamond, belong to electrochemistry technical field, device includes the first shell and second shell connected, the first shell is opened with reaction groove, water is passed to reaction groove in working process;Reaction groove is close to the side of water inlet and is provided with turbulence generator;Patterning diamond anode and patterning cathode are attached to the two sides of proton exchange membrane and constitute electrode group and are arranged in the reaction groove, parallel to the water inlet end and water outlet end of reaction groove and are connected to form straight line;The two sides of electrode group are pressed with metal current collector.The turbulence generator is water wheel or porous microstructure.The application can overcome the problems of poor mechanical strength of traditional through-hole diamond electrode and difficult water and gas transmission on the surface of electrode, while increasing the electrochemical active area of electrode, and thus improving the ozone concentration, reaction efficiency and operating life of the electrochemical oxidation synthesis ozone device.

The application discloses a modular flexible bionic hand based on a dual-mode wire driving, and belongs to the technical field of robots. The dexterous hand comprises a finger assembly, a palm base assembly, an independent driving module, a coupling driving module, an arm base assembly and a tendon; the inner cavity of the arm base assembly is provided with the coupling driving module for driving the opening and closing of the thumb, the index finger and the middle finger simultaneously, and the independent driving module for driving the independent bending of each finger and the lateral bending of the thumb. The bionic hand can be provided with 7 degrees of freedom, adopts a tendon driving mode; the finger assembly is composed of five modular flexible fingers; the knuckles adopt equidistant porous microstructures to improve the shape adaptability and impact resistance, realize the positive active bending and the lateral passive bending; the external driving makes the driving module away from the end effector, and is beneficial to improving the dynamic performance of the bionic hand. The application adopts modular assembly, has the advantages of reliable structure, convenient manufacturing, light weight, high efficiency and low cost.

The invention belongs to the technical field of thermal protection, and relates to a flexible thermal protection structure of a sensor cable in high-temperature test equipment and a preparation method of the flexible thermal protection structure. Comprising an inner fastening coating layer made of a knitted stainless steel mesh; the inner fastening coating layer is used for fastening and coating a sensor cable; the flexible heat insulation layer is tightly coated outside the inner fastening coating layer; the flexible heat insulation layer is made of a flexible alumina fiber needled carpet; the flexible heat insulation ceramic material layer is coated outside the flexible heat insulation layer; the flexible heat insulation ceramic material layer is made of a ceramic nano material with a porous microstructure; the flexible sealing layer is coated outside the flexible heat insulation ceramic material layer; the flexible sealing layer is made of polyimide; the force-bearing shape-fixing layer is wound and coated outside the flexible sealing layer; and the force-bearing shape-fixing layer is made of a glass fiber aluminum foil adhesive tape. The heat insulation performance of the sensor cable is remarkably improved, the service life of the sensor cable in a high-temperature environment is remarkably prolonged, and therefore the accuracy of data collection and the safety of system operation in the high-temperature testing process are ensured.

This application discloses a semi-solid encapsulation particle containing bamboo charcoal filler. The semi-solid encapsulation particle comprises the following components by weight: A. 80-120 parts epoxy resin; B. 150-250 parts modified bamboo charcoal; C. 3-7 parts curing agent. In this solution, modified bamboo charcoal replaces the silica filler in the prior art. Due to the honeycomb-like porous microstructure of bamboo charcoal, the migration path of external pollutant ions into the chip inside the encapsulation layer is significantly increased due to the tortuous channels, improving the environmental protection performance of the encapsulation chip material. Furthermore, through the synergistic effect between epoxy resin and modified bamboo charcoal, the epoxy resin forms multiple micro-curing pillars within the pores of the modified bamboo charcoal, thereby generating strong mechanical locking force and shear strength of the encapsulation material. This not only effectively alleviates the thermal expansion coefficient mismatch stress between the chip and the encapsulation material but also solves the technical problem of encapsulation layer cracking.

The invention discloses a magnetic control semi-filled microsphere flexible sensor and a preparation method thereof, and belongs to the technical field of sensors, the sensor comprises a flexible dielectric layer and an electrode layer, the flexible dielectric layer comprises a flexible substrate and magnetic control semi-filled microspheres with internal core-shell structures; the magnetic control semi-filled microsphere comprises a rigid insulating shell and magnetic conductive powder in an inner cavity. The preparation method comprises the following steps: firstly, preparing a polymer microsphere core containing magnetic conductive powder, and coating a silicon dioxide shell layer on the surface of the microsphere; performing high-temperature heat treatment in a protective atmosphere to form a porous structure; and dispersing the obtained functional microspheres in a flexible matrix precursor, and carrying out curing molding. According to the invention, a unique core-shell structure and a porous microstructure are constructed, the distribution of powder in the microspheres is regulated and controlled by using an external magnetic field, the effective compressible volume and support rigidity of the microspheres in the compression direction are changed, and the problems of poor dispersibility, easy agglomeration and weak interface bonding force of a traditional magnetic conductive material in a flexible matrix are solved; and the sensitivity and the measuring range of the sensor can be regulated.

The invention provides a flexible graphene transformer vibration sensor packaging design method based on a micro-cap structure, and belongs to the technical field of sensors. The method comprises the following steps: preparing an H-type graphene resonator layer on a flexible polyimide substrate; a porous PDMS structure layer containing graphene is constructed on the resonator layer through a salt template method; forming a graphene-containing microstructure layer on the surface of the porous layer by adopting an abrasive paper template method; preparing a micro-cap groove with a silicon dioxide / chromium / gold layer on the silicon-based insulator wafer; and the porous / microstructure layer assembly integrated with the H-shaped resonator and the micro-cap structure layer form a vacuum sealing cavity through gold-silicon eutectic bonding. The flexible graphene vibration sensor designed by the invention can accurately identify wide vibration characteristics in the operation of the transformer, effectively distinguish normal and abnormal working conditions, and can stably work in a complex electromagnetic environment and an oil contamination condition, thereby realizing long-term, accurate and reliable transformer vibration state monitoring.

Embodiments of this application provide a vapor chamber and an electronic device. The vapor chamber includes: a housing, where the housing comprises a top cover and a bottom cover, and the top cover and the bottom cover are connected to form a sealed cavity; and a wick layer disposed in the sealed cavity, wherein the wick layer comprises a capillary structure and the capillary structure is formed by removing top part of a first region of a porous microstructure sheet by a thinning process. According to the technical solution, interference of the vapor chamber with other elements can be reduced.

The invention provides a three-dimensional printing Cu-Ni modified electrode, a preparation method thereof and application of the three-dimensional printing Cu-Ni modified electrode in electro-catalysis nitrate reduction. The prepared three-dimensional printing Cu-Ni modified electrode is prepared through a selective laser melting (SLM) technology, the cost is greatly reduced, the forming time is short, and the three-dimensional Cu-Ni electrode with a solid area and multiple pores is suitable for being applied to an electrochemical reactor for electrocatalytic nitrate reduction; the skeleton of the electrode shows the path of the electrolyte in the porous microstructure of the electrode; when the Cu-Ni working electrode system is used for treating real electroplating wastewater, the NO3 <-> removal rate, the NH3 selectivity and the Faraday efficiency can exceed 70% when the applied voltage is-1.1 V to-1.4 V; good corrosion resistance and long-term stability are realized.

The invention provides a microstructure organic semiconductor layer, a preparation method and application thereof, and an organic field effect transistor gas sensor, and belongs to the technical field of gas sensors. Coating is carried out in a water-containing atmosphere, in the coating process, water molecules in the atmosphere are condensed on the surface of coating liquid, are self-assembled and arranged and are combined with hydrophilic ends in an amphiphilic high-molecular compound through hydrogen bonds, a specific microstructure with the water molecules as a template is spontaneously formed, the water molecules are volatilized after drying, and a honeycomb-shaped ordered porous microstructure is formed. The specific surface area of the organic semiconductor layer is increased, and the contact area with gas molecules is increased, so that the physical adsorption capacity of the microstructure organic semiconductor layer to the gas molecules is enhanced, gas to be detected can be quickly enriched in the organic semiconductor layer, and the sensitivity and response speed of the organic field effect transistor gas sensor are further improved.

The utility model provides an efficient porous microstructure filler, which relates to the technical field of efficient porous microstructure fillers and comprises a top shell, a bottom shell is arranged at the bottom of the top shell, reinforcing rings are arranged on the surfaces of the top shell and the bottom shell, and a mounting frame is arranged in the bottom shell. Through holes with the same size are formed in the surfaces of the top outer shell, the bottom outer shell and the inner shell, the positions of the through holes of the inner shell are consistent with the positions of the through holes in the surfaces of the top outer shell and the bottom outer shell, and under the normal condition, the through holes of the inner shell are aligned with the through holes of the top outer shell and the bottom outer shell. Therefore, when the apertures of the top shell and the bottom shell are too large, the knob on the top surface of the inner shell can be rotated, so that the inner shell is rotated, and the through holes of the top shell and the bottom shell are gradually covered with the positions, without the through holes, of the outer surface of the inner shell, and the apertures of materials passing through the top shell and the bottom shell are reduced; the defect that the diameter of the surface aperture of the filler cannot be adjusted according to a specific use environment is overcome.

The application discloses light high-strength wood and a preparation method thereof. The light high-strength wood has a porous microstructure formed by closely arranging hollow tubular wood cell units, and the wood cell wall is a dense and high-strength unit composed of nanocellulose fibers and lignin. The wood density is about 0.35-0.72 g·cm ‑3 , and the specific strength is 246-444 MPa·g·cm ‑3 . The preparation method comprises the following steps: firstly, removing part of lignin in the wood in situ; secondly, filling a filler into the pore channel and cavity structure of the wood; thirdly, performing radial pressure drying after the filler is solidified; and finally, obtaining the light high-strength wood by removing the filler. The modified high-strength wood of the application greatly retains the porous characteristics of natural wood, maintains the low-density characteristics of the wood, and greatly improves the mechanical properties such as the absolute strength and specific strength of the wood. The application is a high-efficiency cell wall modification method and can be applied to large-scale industrial production.

The invention belongs to the technical field of energy collection, and particularly relates to a mechanical energy collection device based on a bionic structure and a preparation method thereof. The mechanical energy collecting device comprises a polytetrafluoroethylene planar film, a water film, a first electrode, a second electrode, a carbon black film and a porous polytetrafluoroethylene film, the carbon black film is arranged on the porous polytetrafluoroethylene film, the first electrode and the second electrode are arranged on the carbon black film, the water film is arranged on the carbon black film, and the polytetrafluoroethylene planar film is arranged on the water film. According to the invention, the porous membrane is loaded with carbon black to form an electric bilayer with a random porous microstructure, and an ion transport mechanism of a natural plant is simulated. Along with the increase of the pressure, the contact area of the micro-structure electric double-layer coupling capacitor in the solid-liquid channel is increased, and the stored charge quantity is correspondingly increased, which is similar to a liquid charge pump mechanism, so that the energy conversion efficiency of the device is improved.

The application discloses a kind of magnetically controlled semi-filled microsphere flexible sensors and preparation method thereof, belong to sensor technical field, sensor includes flexible dielectric layer and electrode layer, flexible dielectric layer includes flexible matrix and internal core-shell structure magnetically controlled semi-filled microsphere;Magnetic control semi-filled microsphere includes rigid insulating shell and inner cavity's magnetic conductive powder.It is first prepared and the inner core of polymer microsphere containing magnetic conductive powder is coated with silica shell layer on the surface of microsphere;Subsequently, high-temperature heat treatment is carried out under protective atmosphere to form porous structure;The obtained functional microspheres are dispersed in flexible matrix precursor and solidified into shape.The application constructs unique core-shell structure and porous microstructure, uses external magnetic field to control the distribution of powder inside microsphere, changes the effective compressible volume and support stiffness of microsphere in pressure direction, solves the problem that traditional magnetic conductive material is poor in dispersibility, easy to agglomerate and weak in interface bonding force in flexible matrix, realizes the adjustable control of sensor sensitivity and range.

The invention discloses a cascade annular thermo-acoustic stack integrated packaging cooler driven by high-frequency piezoelectricity. The cascade annular thermo-acoustic stack integrated packaging cooler comprises a high-frequency piezoelectric driving sound source, a miniature resonant cavity, a first low-temperature heat exchanger, a first porous microstructure stack, a first heat exchange channel, a second heat exchange channel, a second porous microstructure stack and a second low-temperature heat exchanger. The high-frequency piezoelectric driving sound source is arranged at one end of the micro resonant cavity; the first porous microstructure stack and the second porous microstructure stack are arranged in the miniature resonant cavity at an interval; the outer end of the first low-temperature heat exchanger is connected with the heat source chip, and the inner end of the first low-temperature heat exchanger is connected with the first porous microstructure stack; the first porous microstructure stack, the first heat exchange channel, the second heat exchange channel and the second porous microstructure stack are connected in sequence; the inner end of the second low-temperature heat exchanger is connected with the second porous microstructure stack, and the outer end of the second low-temperature heat exchanger is located in the external environment.

The application discloses Janus structure MXene-CNF aerogel as well as a preparation method and application thereof. The Janus structure MXene-CNF aerogel comprises a CNF layer and a MXene-CNF layer, wherein the CNF layer and the MXene-CNF layer can be self-assembled to form a Janus structure. The Janus structure MXene-CNF aerogel provided by the application is composed of the CNF layer with a porous microstructure morphology, low thermal conductivity, low light absorbance and high infrared emissivity, and the MXene-CNF layer with a sheet layer microstructure morphology, higher thermal conductivity, high light absorbance and low infrared emissivity, and can be widely applied to the thermal management field through the difference of the double-layer optical properties, physical properties and thermal conductivity, and meanwhile, the preparation process is simple, green, energy-saving and low in price, and can meet the demand of industrial production.

A composite that includes an expanded polytetrafluoroethylene (ePTFE) membrane having a porous microstructure. The porous microstructure of the ePTFE membrane is impregnated with a stiffening polymer. An acoustic device assembly that includes the composite and an acoustic device is also described. The composite and the acoustic device assembly can exhibit an insertion loss of less than 7 dB at 1 kHz when measured by the Acoustic Response Measurement (“ARM”) Test.