14 results about "Solar absorptivity" patented technology

The invention relates to an intelligent thermal control device with a high emissivity change value and a low solar absorptivity and a preparation method thereof. The intelligent thermal control device with the high emissivity change value and the low solar absorptivity is of a multi-layer composite structure and sequentially comprises a light base material, an infrared high-reflection metal layer, a transparent medium layer, a VO2 phase change layer, an infrared antireflection layer and a visible light reflection increasing layer from bottom to top. The infrared antireflection layer is made of germanium or silicon; the visible light reflection increasing layer is of a multi-layer structure formed by alternating high-refractive-index material films and low-refractive-index material films, and the materials are at least two of HfO2, Al2O3, TiO2, Ta2O5, SiO2, CaF2, MgF2, ZnSe and ZnS.

The film is of a layered structure, the middle of the film is an organic base material, the base material comprises a first surface and a second surface, and a transition layer, an electromagnetic absorption layer, an isolation layer, an electromagnetic reflection layer and a thermal radiation reflection layer are sequentially distributed on the first surface and the second surface. Meanwhile, penetrating through holes are distributed in the surface of the film, and conductive layers are attached to the inner walls of the through holes to communicate all the layers. The thin film utilizes the closed reflection effect of the electromagnetic reflection layer and the loss effect of the electromagnetic absorption layer, and the electromagnetic shielding effectiveness of the thin film in the wave band of 10 MHz to 10 GHz is larger than 80 dB; the hemispherical emissivity of the heat radiation reflecting layer on the outermost layer is 0.03-0.05, and the solar absorptivity is 0.09 + / -0.02. The preparation method of the thin film comprises the steps of substrate plasma modification, magnetron sputtering deposition of the multi-layer functional film, punching, vacuum evaporation plating of the heat radiation reflecting layer, annealing treatment and the like, and the process controllability is high. The thin film integrates the functions of electromagnetic shielding, thermal control, static prevention and heat dissipation, and has important application value in the field of aerospace equipment.

The application discloses a heat control device and method for a flexible thin film antenna in space, which is mainly used for providing heat control for large flexible antennas such as phased array radars in space. A solar shield with high infrared emissivity, low solar absorptivity and microwave permeability is arranged on the front surface of the antenna, and when the back surface of the antenna is irradiated by the sun, the solar shield can quickly dissipate heat by using the high infrared emissivity, and when the front surface of the antenna is irradiated by the sun, the solar shield can prevent the antenna from absorbing too much heat and making the temperature of the antenna too high by using the low solar absorptivity; an insulating layer and a low solar absorptivity coating are arranged on the back surface of the antenna, and when the back surface is irradiated by the sun, the low solar absorptivity coating can reflect most of the solar heat, and when the back surface is in a shadow area, the insulating layer can prevent the temperature of the antenna from being too low. Therefore, the antenna can always be in a relatively suitable temperature range in the complex and changeable space orbit thermal environment. The application has the characteristics of strong adaptability and wide applicability.

This invention discloses a tethered binary star multi-condition adaptive thermal control structure, including a primary star thermal control module, a secondary star thermal control module, a dynamic thermal management module, and a binary star collaborative thermal management module. The adaptive thermal control structure adopts a hybrid architecture of passive heat dissipation as the primary method and active heating as a secondary method. The primary star thermal control module has a low solar absorptivity, high infrared emissivity, and anti-atomic oxygen white paint coating applied to the -X, -Y, and +Z planes of the primary star. It is equipped with a 10-unit modular multilayer thermal insulation component and a high thermal conductivity graphite film, with the overall weight controlled to ≤1.25kg. This invention is rationally designed and provides a hybrid thermal control architecture of passive heat dissipation as the primary method and active heating as a secondary method, achieving primary / secondary star zoned thermal control, multi-condition dynamic adaptation, and binary star collaborative thermal management, meeting weight, power constraints, and full-cycle temperature requirements.

The invention relates to a near-blackbody high-entropy inverse spinel oxide material, the general formula of the material is (A1xA2yA3zA4uA5v) 3O4, A1, A2, A3, A4 and A5 are any five elements of Fe, Ni, Co, Cr, Mn, Cu and Ti, x, y, z, u and v are equal or approximately equal, and x + y + z + u + v = 1; the structure of the material belongs to a cubic system and has an inverted spinel crystal structure, and the space group of the material is Fd-3m. Meanwhile, the invention also discloses a preparation method of the material. The method is simple to operate and short in production cycle, the obtained high-entropy inverse spinel oxide material has high solar absorptivity and infrared emissivity, the radiation curve of the high-entropy inverse spinel oxide material is close to an ideal black body radiation curve, and the high-entropy inverse spinel oxide material can be widely applied to the fields of radiation heating, human body heat management, aerospace heat dissipation, photovoltaic device cooling and the like.

The application discloses a preparation method of multifunctional leather-based wearable material based on dynamic heat conversion, specifically comprising the following steps: preparing a radiative cooling layer on the grain side of leather; mixing poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, multi-walled carbon nanotube powder, trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane and PDMS, adding ethyl acetate, stirring, then ultrasonic stirring, spraying on the flesh side of the leather, and drying, so multifunctional leather-based wearable material is prepared.The multifunctional leather-based wearable material prepared by the application has excellent asymmetric wettability, flame retardancy, electrical conductivity, joule heating, electromagnetic shielding, physiological signal monitoring and switchable thermal management performance.The radiative cooling layer has a solar reflectance of about 90.13% and a mid-infrared emissivity of about 87.6%, and the heating layer has a solar absorptivity of about 89%.

The invention provides a spectrum selective absorption thermal control filler and a preparation method thereof, the chemical composition of the spectrum selective absorption thermal control filler is Ti < 1-x > MxO < 2-0.5 x >, M represents one or more of Gd, Yb and Ga, x is more than 0 and less than or equal to 0.5, and titanium dioxide and trivalent oxide powder are subjected to solid-phase synthesis in a high-temperature environment. Titanium oxide is doped with trivalent oxide, oxygen vacancies are introduced while lattice distortion is generated, lattice symmetry is reduced, carrier concentration is improved, an infrared absorption band is widened, low solar absorption ratio is kept while high emissivity is obtained, and selective absorption of spectrums is achieved; and the infrared emissivity at 600 DEG C can reach 0.80-0.85, the solar absorptivity is 0.20-0.35, and an excellent high-temperature heat dissipation effect is achieved.

The invention discloses a heat dissipation electromagnetic shielding film for spaceflight and a preparation method thereof, the prepared film is of a multi-layer structure, and a transition layer, an electromagnetic absorption layer, an isolation layer, an electromagnetic reflection layer and a thermal radiation reflection layer are sequentially arranged on a first surface of a base material; an electromagnetic reflecting layer, a heat radiation reflecting layer, a heat radiation layer and an anti-static layer are sequentially arranged on the second surface of the conductive base material; through holes are distributed in the surface of the electromagnetic shielding film; metal coatings are attached to the inner walls of the through holes, and all layers of the thin film are communicated through the metal coatings. The anti-static layer is prepared by sequentially sputtering the electromagnetic reflecting layer on the second surface of the base material, depositing the thermal radiation reflecting layer through vacuum evaporation, then coating the thermal radiation layer and curing, and coating conductive liquid or in a magnetron sputtering mode. The second surface of the electromagnetic shielding film has low solar absorptivity and high hemispherical emissivity, the solar absorptivity is less than or equal to 0.40, the hemispherical emissivity is not less than 0.60, and the electromagnetic shielding film has a good heat dissipation function and adapts to harsh application scenes in the aerospace field.

The application relates to a spinel-perovskite dual-phase high-entropy ceramic powder material, which has a chemical formula AMn x O y wherein A is three transition metal elements selected from Cu, Ni, Co, Zn and Mg and one rare earth element selected from La, Pr and Nd, the elements are in equal molar ratio, 1 < x < 2 and 3 < y < 4, the material has a face-centered cubic crystal structure spinel phase and a perovskite phase. Meanwhile, the application also discloses a preparation method of the high-entropy ceramic powder material. The high-entropy ceramic powder material has the characteristics of two-phase coexistence, high purity, small particle size (100-400 nm) and uniform element distribution, and has excellent solar absorptivity (>0.87), infrared emissivity (>0.90) and high-temperature thermal stability (1600 DEG C), and can be widely used in the field of high-temperature thermal radiation, including aerospace, industrial kiln, power station boiler and the like, as an infrared radiation material and a solar energy absorption material.

The application discloses a composite textile with passive radiative cooling and heat preservation functions and a preparation method thereof, and the method comprises the following steps: preparing a porous polypropylene fiber membrane through a melt-blown process, depositing silicon dioxide nanoparticles through ultrasonic deposition, and then adopting a laminating process to combine a polyurethane microporous membrane and a carbon nanotube film, so that the composite textile with double-mode heat management characteristics is obtained. When the polyurethane layer faces the sun, the material shows high solar reflectivity and high infrared emissivity in the atmospheric window band, so that efficient passive radiative cooling is realized; when the carbon nanotube film faces the sun, the material has high solar absorptivity and low infrared emissivity, so that excellent heat preservation performance is realized. The method is simple in process, suitable for large-scale production, can effectively reduce energy consumption, and has a wide application prospect in the fields of personal heat management and the like.

The invention provides a thermal control structure suitable for an MEO microwave antenna, and belongs to the field of space thermal control. The MEO microwave antenna thermal control structure comprises an anti-radiation thermal control film, curing glue and a low-heat-conduction supporting column. The supporting column is installed on the surface of the microwave antenna waveguide through threads, and the anti-radiation thermal control film is attached to the top face of a cylindrical head of the supporting column through curing glue points. The thermal control film has low solar absorptivity and high hemispherical emissivity, the inner surface of the thermal control film performs radiation heat exchange with the waveguide, and the outer surface of the thermal control film performs radiation heat exchange with the space heat sink; the supporting columns are made of low-heat-conduction materials, heat conduction heat resistance from the waveguide to the thin film is increased, and heat leakage to a space heat sink is reduced. According to the invention, the compensation power consumption of the heater is remarkably reduced while the temperature of the antenna assembly meets the long-term working requirement in the MEO irradiation environment, and the space environment adaptability, the heat dissipation reliability and the wave-transparent performance are considered.

The invention relates to medium-entropy inverse spinel multivalent oxygen vacancy synergetic broadband infrared emission ceramic, the general formula of the ceramic is (A1xA2yA3zA4u) Fe2O4, A1, A2, A3 and A4 are any four elements of Mg, Ni, Co, Cr, Mn and Cu, x, y, z and u are equal or approximately equal, x + y + z + u = 1, and the molar ratio of (x + y + z + u) to Fe is 1: 2; the ceramic structure belongs to a cubic system inverse spinel crystal structure, and the space group of the ceramic structure is Fd-3m. The medium-entropy inverse spinel ceramic material is prepared by adopting a mechanical wet grinding method and a rapid Joule heating combined method, has the advantages of high heating speed, high production efficiency, short production period, applicability to automatic operation and the like, and has relatively high solar absorptivity and infrared emissivity; the material can be widely used as an infrared radiation material in the fields of aerospace radiation heat dissipation, industrial heating, human body heat management and the like.

According to the method for improving the surface roughness of the reflecting surface of the composite material antenna, a composite material component is trimmed to be below 10m for resin layer spraying, the thickness uniformity of a resin-rich layer is improved, then the thickness of the resin-rich layer is further ground, the thickness of the resin-rich layer is controlled to be about 40m, and the surface roughness of the reflecting surface of the composite material antenna is improved. And the possibility of cracking and deformation risks of the resin in high and low temperature environments is reduced. By adopting the method for improving the surface roughness of the reflecting surface of the composite material antenna, the surface roughness of the reflecting surface of the antenna is reduced to about 130nm by using parameters such as water-sand mixed liquid with different particle sizes, the diameter of the polishing disk, the pressure of the polishing disk, the revolution speed of polishing, the polishing time and the like, and then the surface roughness is improved; therefore, the surface roughness is controlled within a certain range, and the optimal state of the solar absorptivity and reflectivity is achieved.

This invention discloses a space-simulated environment variable-temperature photothermal performance testing device based on steady-state calorimetry: the outer layer of the experimental chamber is a vacuum chamber, and the inner layer is a cryogenic chamber, with gas communication between the vacuum chamber and the cryogenic chamber; before testing, the cryogenic chamber is cooled by a cooling device, and the interior of the experimental chamber is evacuated to a vacuum state by a suction device, so that the interior of the experimental chamber meets the testing environment. A sample installation and adjustment unit is used to install and fix the sample to be tested in the cryogenic chamber. A temperature control unit is used to change the temperature of the sample to be tested. A solar radiation simulation unit is used to simulate sunlight irradiation. When the sample to be tested reaches the preset temperature, the data processing unit records the corresponding vacuum level and the output power of the temperature control unit, and calculates the emissivity of the sample to be tested by combining parameters such as the temperature inside the cryogenic chamber and the radiative area of ​​the sample. This invention achieves continuous and simultaneous measurement of full-spectrum hemispherical infrared emissivity and solar absorptivity from 150K to 450K, with a large temperature range and high measurement accuracy.