183 results about "Vanadium dioxide" patented technology

The invention discloses a bifunctional chiral metamaterial surface capable of switching polarization conversion and wave absorption, and belongs to the technical field of electromagnetic metamaterials. The method is used for solving the problem that most existing chiral super-structure surfaces cannot realize dynamic adjustability and quantitative controllability and cannot have dual functions of polarization conversion and wave absorption at the same time. The super-structure surface unit structure is composed of a graphene film layer, a gold-vanadium dioxide resonance layer, a silicon dielectric layer and a bottom-layer continuous gold film. Switching of two functions of polarization conversion and wave absorption is realized by changing the conductivity of vanadium dioxide; polarization conversion and dynamic regulation and control of the wave absorbing efficiency are realized by changing the Fermi level of the graphene; quantitative controllability of polarization conversion and a wave absorbing function is realized by controlling a function weighting function. Besides, the chiral super-structure surface also has the advantages of incident angle robustness, small thickness and small size, has double functions of broadband, and has potential application value in the fields of optical devices, communication equipment, biomedical sensors and the like.

The invention belongs to the field of functional nano materials, and relates to a method for large-scale preparation of monoclinic phase vanadium dioxide nano powder, a heat insulation film and application of the heat insulation film, and large-scale preparation of the monoclinic phase vanadium dioxide nano powder is successfully achieved by combining a coprecipitation method with low-temperature calcination. The obtained product has excellent size uniformity (the average particle size is 65 + / -10 nm) and an adjustable phase change characteristic (61-68 DEG C). The polymer-based composite film prepared based on the nano powder shows excellent optical performance, and the method has the advantages of mild reaction conditions (less than or equal to 600 DEG C), controllable product morphology and phase transition temperature and the like, and provides a reliable solution for industrial production of nano functional materials for intelligent windows.

The invention relates to the technical field of building energy-saving intelligent windows, and discloses a sunlight and heat radiation multi-adjustment intelligent window and a preparation method and application thereof. The intelligent window comprises an outer surface layer, a middle layer and an inner surface layer which are stacked in sequence. The outer surface layer comprises an infrared transparent layer, and an infrared reflecting layer and a doped vanadium dioxide layer which are respectively arranged on two opposite surfaces of the infrared transparent layer; the inner surface layer comprises a transparent substrate and a conductive layer attached to the surface of one side of the transparent substrate; the middle layer is a liquid crystal / polymer dimming layer, one side of the liquid crystal / polymer dimming layer is bonded with the infrared reflecting layer, and the other side of the liquid crystal / polymer dimming layer is bonded with the conductive layer. According to the intelligent window, multiple cooperative regulation and control of sunlight and heat radiation can be achieved, the regulation and control wave band is wide, the response speed is high, and the energy-saving effect is good. The regulation and control wave band covers visible light, near infrared and middle and far infrared ranges, reversible change can be realized along with the change of environment temperature, and all-year-round and all-weather energy saving is realized.

The application relates to a preparation method and application of a ball milling-calcination process-prepared cesium vanadium tungstate mixed heat insulation coating, and belongs to the technical field of heat insulation coatings. The application aims to solve the problems of high preparation cost, strict requirement on equipment, long preparation time and difficult morphology control of vanadium dioxide and cesium tungsten bronze used in the existing cooling coating. The prepared cesium vanadium tungstate mixed heat insulation coating is coated on the surface of glass, mainly aiming at blocking the infrared light thermal radiation in sunlight, the new type of high-efficiency heat insulation film utilizes the light absorption and phase change reflection characteristics of nanometer cesium tungsten bronze and vanadium dioxide to realize heat insulation. The application adjusts the proportion of cesium, vanadium and tungstate to adjust the heat insulation performance, the heat insulation coating is prepared through different proportions of acrylic resin / organic silicon resin, solvent, cesium vanadium tungstate mixed heat insulation coating and the like, and the heat insulation film with excellent infrared blocking property, good stability and excellent light transmittance is obtained.

Methods for preparing catalysts for oxidative dehydrogenation (ODH) of alkanes such as ethane are provided. An exemplary method includes forming a slurry including metal oxides; one or more of a bismuth compound, an antimony compound, and a tellurium compound; a reducing agent; and water; and heating the slurry to form the catalyst. The metal oxides include an oxide of molybdenum and an oxide of vanadium. The bismuth compound includes bismuth oxide, bismuth hydroxide, or a bismuth carbonate. The antimony compound includes an oxide of antimony, an antimony acetate, or an antimony ethoxide. The tellurium compound includes tellurium dioxide. The reducing agent includes molybdenum dioxide and may further include vanadium dioxide. The methods use all inorganic reagents, with no build up COx pressure observed during the hydrothermal synthesis.

The invention belongs to the technical field of glass for buildings, and discloses a thermochromic intelligent window based on a vanadium dioxide nanoparticle film concentration gradient structure and a preparation method thereof.The preparation method comprises the steps that firstly, two parts of W-VO2 nanoparticles with different masses and PVP are added into absolute ethyl alcohol to be subjected to ultrasonic oscillation, and the W-VO2 nanoparticles and PVP are stirred to be evenly distributed and then stand for use; the method comprises the following steps: sequentially coating the surface of a pretreated glass substrate with W-VO2amp with relatively high concentration from bottom to top; a PVP dispersion liquid, a PMMA dispersion liquid, and low-concentration W-VO2amp are added; a PVP dispersion liquid; therefore, a W-VO2 gradient structure with low concentration at the top layer and high concentration at the bottom layer is formed on the surface of the glass substrate. The visible light transmittance of the thermochromic intelligent window is greatly improved, meanwhile, the solar modulation capacity is improved, the antagonism between the two optical properties of the visible light transmittance and the solar modulation efficiency is weakened or even broken through, and thermochromic development of the intelligent window and the radiation refrigeration field is further promoted.

The present invention discloses an ultra-wideband, multi-frequency switchable terahertz absorber based on vanadium dioxide, belonging to the field of terahertz wave technology. The absorber comprises: an ultra-wideband, multi-frequency switchable terahertz absorber unit having a multi-layer structure, wherein, from top to bottom, a mutually bonded upper patterned VO2 layer, an upper SiO2 dielectric layer, a lower VO2 layer, an intermediate patterned gold layer, a lower SiO2 dielectric layer, and a bottom gold layer are sequentially arranged; the upper patterned VO2 layer is disc-shaped, with a square annular slit disposed within the disc; the intermediate patterned gold layer comprises an inner ring, an outer ring, and an open square ring, spaced from the inside out, with the opening of the open square ring disposed in the middle of each edge. The present invention is based on an ultra-wideband, multi-frequency switchable terahertz absorber based on vanadium dioxide. The designed absorber can achieve switching from ultra-wideband absorption to multi-frequency absorption by adjusting the conductivity of the vanadium dioxide through temperature control.

The invention discloses a reconfigurable intelligent metasurface device with switchable transmission and reflection polarization conversion based on deep learning and a design method, and belongs to the technical field of multifunctional metasurface devices and computers. The device comprises a top metal resonator, a middle dielectric layer and a bottom functional layer containing a vanadium dioxide phase change material. The phase state of VO2 is changed through external excitation, dynamic switching of the device between a transmission polarization conversion working mode and a reflection polarization conversion working mode can be achieved, and the problem that an existing device is single in function is solved. The design method comprises the steps that a forward prediction network embedded with physical mechanism constraints is constructed, a loss function of the forward prediction network comprises data loss and physical loss based on a polarization conversion rate physical formula, and the physical consistency of prediction is improved; and constructing a reverse design network based on bidirectional LSTM and CBAM attention mechanisms, and rapidly solving device structure parameters according to the target spectrum. According to the invention, full-space multifunctional regulation and control of the device are realized, and the design efficiency and reliability are remarkably improved.

The invention discloses an intelligent early warning cable and a preparation method of the intelligent early warning cable, and belongs to the technical field of cables. The flame-retardant polyolefin composite material is prepared from the following raw materials in parts by weight: 5 to 10 parts of ethylene-vinyl acetate copolymer, 10 to 20 parts of linear low-density polyethylene, 10 to 15 parts of ethylene-octylene copolymer, 3 to 8 parts of compatilizer, 15 to 20 parts of organic modified vanadium dioxide, 30 to 40 parts of ionic liquid modified aluminum hydroxide, 1 to 1.5 parts of cross-linking agent and 1 to 2 parts of lubricant. Organic modified vanadium dioxide is introduced into a sheath layer material to serve as an intelligent early warning material, the cable sheath layer is endowed with the temperature change characteristic, when the local temperature of the cable is abnormally increased due to overload and other reasons, the material can trigger color change, and therefore a striking visual mark is formed in a complex wire harness, and the early warning effect is improved. And the problems of lag, low efficiency and existence of blind areas of the traditional monitoring means are solved.

The application relates to a composite ultrathin full-transparent intelligent intermediate connecting layer, which comprises, from top to bottom, a first composite electrode, a photonic management composite tunneling layer and a second composite electrode; the first composite electrode is a grid-shaped transparent conductive film formed by reducing graphene oxide and silver nanowires, wherein the diameter of the silver nanowires is 20-40 nm, the length is 15-40 mu m, and the mass ratio of the reducing graphene oxide to the silver nanowires is 1:3 to 1:6; the photonic management composite tunneling layer is a zinc oxide matrix embedded with perovskite quantum dots; and the second composite electrode is an intelligent response electrode formed by combining aluminum-doped zinc oxide and vanadium dioxide; through accurate regulation of the material and structure, the application realizes >88% light transmittance and <35 Omega / sq square resistance, and simultaneously has the functions of photonic down-conversion and intelligent thermal management, thereby significantly improving the performance and stability of a stacked battery.

The invention discloses a stealth coating material for aviation aircrafts. According to the invention, a three-layer composite structure design is adopted; the intelligent sensing layer is composed of graphene quantum dots and a piezoelectric nanofiber composite network, so that real-time sensing of electromagnetic wave signals is realized; the tunable metamaterial layer comprises a liquid crystal elastomer matrix and nickel-titanium alloy nanowires dispersed in the liquid crystal elastomer matrix, and electromagnetic parameters of the material are dynamically adjusted by applying an electric field or a temperature field; vanadium dioxide nanoparticles, a photonic crystal structure and carbon nanotube aerogel are integrated in the multispectral stealth layer, and radar, infrared and visible light multispectral synergistic stealth is achieved. The coating is further integrated with a microencapsulation repairing agent and an intelligent control system, and has the self-repairing and self-adaptive adjusting functions. Compared with the prior art, 0.1-40 GHz ultra-wide frequency band radar wave absorption is achieved, the radar cross section is reduced by 25-30 dB, the infrared radiation characteristic is reduced by 80% or above, the surface density is only 1.2-1.5 kg / m, the weight is reduced by 65% compared with a traditional coating, and a key material technical support is provided for a new generation of stealth aircrafts.

The application discloses a multifunctional intelligent photovoltaic window which is assembled by a multifunctional variable color unit and a silicon solar cell, and has the characteristics of wide wave adjustment, self-driving and self-cleaning. The laminated structure multifunctional variable color unit mainly comprises a vanadium dioxide / silicon dioxide / polyurethane nanocomposite film, a polymer stable liquid crystal with a near-crystal-cholesteric phase transition, an indium tin oxide and a silicon dioxide coating, which are respectively used as a near-infrared light adjusting layer, a visible light adjusting layer, an electrothermal layer and a super-hydrophobic layer. Based on the above design, the intelligent photovoltaic window can realize dynamic adjustment of the transmittance in the wavelength range of 380-2500 nm, so that the ideal energy-saving effect is achieved. In combination with the high output power of the silicon cell and the excellent direct current heating effect of the indium tin oxide, the self-driving characteristic of the intelligent photovoltaic window is realized, and the energy-saving effect is further improved. In addition, the silicon dioxide super-hydrophobic coating with a contact angle of 150-160 degrees effectively solves the environmental dependence of the intelligent photovoltaic window, and the intelligent photovoltaic window also has a good vision under complex weather conditions such as rain and snow. The application can widen the application of the intelligent photovoltaic window in the fields of energy-saving buildings, automobiles and flexible photoelectric devices.

The application relates to a preparation method of a diffused island-shaped vanadium dioxide thermochromic film. The preparation method comprises the following steps: a precursor forming step: forming a vanadium oxide film with a thickness of 20-100 nm as a precursor on the surface of a substrate by a magnetron sputtering method, a thermal deposition method or a laser-induced vapor deposition method; a pretreatment step: heating the film to 600-950 DEG C at a temperature increasing rate of more than 80 DEG C / min in an annealing furnace with a pressure of 50 mTorr or less, then keeping the temperature for 5-30 min, and then cooling the film to 300-450 DEG C in the furnace to form the film into a diffused island shape; and an oxidation step: introducing oxygen into the annealing furnace to oxidize the film to obtain a vanadium dioxide film. The film prepared by the preparation method of the vanadium dioxide thermochromic film has good sunlight modulation efficiency and good light transmittance.

The present invention discloses a dual-frequency / broadband switchable dynamically tuned metamaterial terahertz absorber, comprising M*N multilayer terahertz absorption units, each of which is distributed in an M*N two-dimensional pattern, where M and N are both positive integers. Each multilayer terahertz absorption unit comprises a metal substrate, a dielectric layer, and a resonant layer, arranged sequentially from bottom to top. The dielectric layer and the metal substrate are both square in shape with equal sides. The resonant layer comprises a single-layer graphene layer with a hollow cross, wherein a solid cross-shaped vanadium dioxide layer is embedded in the hollow portion of the single-layer graphene layer with the hollow cross. The single-layer graphene layer with the hollow cross has a cross-shaped shape. The absorber is dynamically tuned, has polarization insensitivity, and can maintain stable absorption within an incident angle range of 0-60°. A preparation method for the dual-frequency / broadband switchable dynamically tuned metamaterial terahertz absorber is also disclosed.

The invention discloses a metal oxide composite sodium ferric sulfate positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of sodium ion battery positive electrode materials. The metal oxide composite sodium ferric sulfate positive electrode material comprises the following raw materials in parts by mass: 1-20 parts of sodium sulfate, 2-40 parts of ferrous sulfate, 0.05-1 part of an antioxidant, 0.05-1 part of a carbon source and 0.01-2 parts of metal oxide, the metal oxide is at least one of ferrous oxide, ferric oxide, ferroferric oxide, manganese oxide, manganese dioxide, cobalt oxide, cobaltosic oxide, cobaltic oxide, vanadium monoxide, vanadium dioxide, vanadium trioxide, vanadium pentoxide, nickel oxide and copper oxide. The invention also discloses a preparation method and application of the metal oxide composite sodium ferric sulfate positive electrode material. The method provided by the invention can solve the problems of low conductivity and specific capacity of the existing sodium ferric sulfate positive electrode material, and has the advantages of low cost, strong process adaptability and wide application prospect.

A thermochromic material comprising vanadium dioxide (VO2) nanoparticles dispersed on surfaces of larger scaffolding particles such as amorphous silicon dioxide (SiO2). The SiO2 particles prevent the vanadium dioxide nanoparticles, which are typically less than approximately 40 nm in size, from sintering into larger particles, thus giving the material advantageous properties. A base added to the vanadium precursor solution functionalizes the scaffolding particles. The size of the vanadium dioxide nanoparticles can be changed by changing the size of the scaffolding particles. The material can be dispersed in a coating, film, ink, plastic, or polymer.

The application provides a method for preparing an M-phase VO2 film by a light-assisted spray pyrolysis method and the M-phase VO2 film prepared by the method, and belongs to the field of nanometer materials. The method comprises the following steps: (1) preparing a vanadium dioxide spraying liquid: adding vanadium oxyacetonylacetone into anhydrous methanol, stirring and aging to obtain a vanadium dioxide spraying liquid with ultraviolet photosensitive properties; (2) preparing a vanadium dioxide film: introducing the vanadium dioxide spraying liquid in step (1) into an atomizer and spraying onto a substrate coated with a TiO2 anatase phase under ultraviolet light irradiation to obtain the M-phase VO2 film. The method enables vanadium ions to be chelated in the sol by stirring, and the vanadium dioxide spraying liquid has ultraviolet photosensitive properties. The purity of the VO2(M) film is improved by introducing a titanium dioxide transition layer, and the microstructure of the VO2(M) film is improved by ultraviolet light irradiation, thereby improving the visual transmittance and solar light regulation rate of the VO2(M) film.

The invention provides a portable mid-infrared pulse fiber laser, a working method and a laser system thereof. The portable mid-infrared pulse fiber laser comprises a pumping source, a first convex lens, a dichroic mirror, a second convex lens, a rare earth ion doped fiber, a third convex lens, a fourth convex lens, a vanadium dioxide saturable absorber, a semiconductor heating sheet, a direct current power supply and a wire which are sequentially arranged along an optical axis. According to the working method, the temperature of the vanadium dioxide saturable absorber is controlled by starting electric control of the semiconductor heating sheet and adjusting the control voltage of the direct-current power supply; when the temperature reaches heat balance, a pumping source is started; the power of the pumping source is increased until the power threshold of the passive Q-switched pumping light is reached, and the dichroscope outputs mid-infrared passive Q-switched pulse laser. The laser system comprises the laser and a control circuit. Under the condition of low pumping power, high-peak-power, high-pulse-energy and nanosecond-level narrow-pulse-width mid-infrared passive Q-switched pulse fiber laser output is achieved; and the portability and the practicability of the laser are improved due to the portability and long-endurance design.

The invention relates to the technical field of optical sensors, in particular to a super-multilayer dielectric film structure optical refractive index sensor based on Fano resonance. The device sequentially comprises a prism layer, a modified cerium oxide layer, a functional layer, an interface layer, a substrate layer and a to-be-detected dielectric layer from top to bottom, the prism layer is a rutile prism, the substrate layer is an SOI substrate, and in the to-be-detected dielectric layer, a to-be-detected medium comprises water and ethanol; the interface layer is arranged on the substrate layer in a coating manner, the functional layer comprises a plurality of groups of units obtained by alternate deposition, and each unit comprises a vanadium dioxide layer and an indium trichloride tetrahydrate doped SiO2 layer which are arranged in sequence. The invention provides an optical refractive index sensor with a super-multilayer dielectric film structure based on Fano resonance, and aims to solve the problems of relatively low sensor sensitivity caused by relatively high cost and poor binding force with oxide materials of precious metals used in traditional materials and relatively weak surface plasmons excited by some oxide materials in related technologies.

The present invention relates to a large-area radiative cooling film and a method for manufacturing same. The radiative cooling film can be produced to exhibit excellent emissivity and infrared transmittance, by synthesizing highly crystalline single-crystal vanadium dioxide through a chemical vapor deposition method, and optimizing the structure thereof, such as the vanadium dioxide pattern, spacing, and the thickness of each layer. In addition, the method for manufacturing a radiative cooling film can improve process speed and stability through a film thinning process based on dry transfer, and enables the manufacture of a large-area radiative cooling film.

This invention discloses a thermochromic smart window, which contains at least one layer of thermochromic material. The core functional material of the thermochromic material is a core-shell structured thermochromic material, with doped vanadium dioxide nanoparticles as the core and a metal-organic framework as the shell. The thermochromic smart window of this invention exhibits high stability, good optical properties, and the ability to achieve synergistic photothermal response, making it particularly suitable for home use. Furthermore, its preparation method is simple, requires mild conditions, and is highly compatible with existing laminated glass manufacturing processes, facilitating industrialization. It not only responds to changes in ambient temperature but also sensitively responds to changes in solar radiation intensity, achieving intelligent regulation of solar thermal energy.

The present invention relates to a method for producing vanadium dioxide using a tetra-arc melting method. Unlike conventional methods that require complex wet processes, long-term high-temperature heat treatment, and multi-stage reduction conditions, this method provides vanadium dioxide with high crystallinity by concentrating electrical energy on a pellet during a short arc discharge time of within a few seconds. This highly crystallin VO₂ has an accurate phase transition temperature, making it effective for use in various applications such as smart windows, heat-blocking coatings, optical films, temperature sensors, thermal switching devices, and next-generation battery materials. Furthermore, the present invention is expected to be utilized across various industrial sites, as it enables the production of highly crystalline vanadium dioxide in a much shorter time compared to existing heat treatment-based technologies, despite its simple device configuration and low manufacturing costs.

The invention discloses a heat-insulating car window film and a preparation method thereof, and relates to the technical field of films. The heat-insulating car window film prepared by the invention comprises modified polyurethane and modified vanadium dioxide, the modified polyurethane is obtained by polymerizing polycarbonate diol, hexamethylene diisocyanate and a dihydric alcohol monomer and then carrying out end capping by using 2, 3, 3-trimethyl-3H-indole-7-alcohol; the modified vanadium dioxide is obtained by polymerizing pre-treated vanadium dioxide coated with methyl methacrylate, 1-(pent-4-ene-1-yl)-1H-pyrrole, squaric acid and an intermediate, and the pre-treated vanadium dioxide is coated with 1-(pent-4-ene-1-yl)-1H-pyrrole. The heat-insulating car window film prepared by the invention has good heat-insulating, flame-retardant and anti-aging properties.

The invention relates to the field of terahertz metamaterial devices, and provides a reconfigurable broadband / multi-frequency terahertz wave absorber based on vanadium dioxide. The wave absorber is composed of metamaterial square units which are arranged periodically, and adjacent units are gapless. Each unit is composed of six layers of structures including a vanadium dioxide resonance layer, an upper polyimide dielectric layer, a vanadium dioxide thin film layer, a copper resonance layer, a lower polyimide dielectric layer and a copper substrate layer. Vanadium dioxide can realize reversible phase change between a metal state and an insulation state through external excitation. In a metal state, the wave absorber has an ultra-wideband terahertz wave absorption function; and in an insulated state, a double-narrow-band absorption function is shown. According to the invention, the reconstruction of the absorption frequency and the bandwidth of the terahertz wave absorber is effectively realized, the problems of complex structure and fixed function of a traditional terahertz sensor are solved, and the potential of the terahertz wave absorber in sensing application of a single narrow-band wave absorber is further discussed.

The invention provides a vanadium dioxide temperature compensation gas flow sensor, and belongs to the field of sensor manufacturing. The sensor comprises a silicon substrate, a silicon oxide and silicon nitride layer, a heat insulation cavity, a heat insulation gap, a chromium adhesion layer, a vanadium dioxide temperature measurement resistor, a platinum heating resistor, a platinum environment temperature measurement resistor, a platinum wire and a platinum electrode, wherein a heating resistor is arranged in the center of the silicon oxide and silicon nitride layer suspended above the cavity, four vanadium dioxide temperature measurement resistors are symmetrically distributed on two sides of the heating resistor to form a Wheatstone bridge, a heat insulation gap is formed between the heating resistor and the temperature measurement resistors, and platinum environment temperature measurement resistors are distributed on the upstream and the downstream of the cavity area. When no gas flows in, chip heat distribution is symmetrical, and upstream and downstream vanadium dioxide temperature measuring resistors have the same resistance value; when gas flows in, the resistance value of upstream vanadium dioxide is increased, the resistance value of downstream vanadium dioxide is decreased, the Wheatstone bridge outputs voltage, the relation between the voltage value and the gas flow is recorded, and then the flow is compensated and corrected according to the values of the environment temperature measuring resistor and the heating resistor to obtain the final gas flow value.

To provide a solid heat storage material containing vanadium dioxide and aluminum and enabling suppression of reduction in latent heat.SOLUTION: A solid heat storage material is a composite of vanadium dioxide and an aluminum alloy, the aluminum alloy containing at least one of silicon or copper and having a composition that does not reduce vanadium dioxide compared with pure aluminum.SELECTED DRAWING: None

The invention provides a steel surface phase-change intelligent temperature-adjusting water-based anti-corrosion and anti-rust paint as well as a preparation method, application and a construction method thereof, and belongs to the field of building materials. Reflection and radiation materials and phase-change materials such as nanometer aluminum oxide, nanometer silicon-based oxide, nanometer yttrium oxide, glass microspheres and nanometer vanadium dioxide are added into the steel surface phase-change intelligent temperature-adjusting water-based anti-corrosion and anti-rust paint disclosed by the invention; the hemispherical emissivity, the medium-brightness sunlight reflectance, the near-infrared light reflectance and the phase-change intelligent temperature-adjusting function of the phase-change intelligent temperature-adjusting water-based anti-corrosion and anti-rust paint on the steel surface are synergistically enhanced; by adding the derusting agent, the anti-flash-rust agent, the multifunctional anti-rust powder, the zinc phosphate, the aluminum triphosphate and the mica powder, the anti-corrosion and anti-rust effects of the steel surface phase-change intelligent temperature-adjusting water-based anti-corrosion and anti-rust paint are improved. Results of the embodiment show that the steel surface phase-change intelligent temperature-adjusting water-based anti-corrosion and anti-rust paint is excellent in anti-corrosion and anti-rust effects.

The present invention provides a thermally induced phase change solar heat collector tube and its coating method. A vacuum interlayer is formed between the heat-absorbing section of the inner tube and the cover glass tube. The outer wall of the heat-absorbing section is coated with a selective absorption coating. The selective absorption coating comprises an infrared reflection layer, a low-resistance layer, a transition layer, a high-resistance layer, and an anti-reflection layer, sequentially formed on the outer wall of the heat-absorbing section. Furthermore, each of the low-resistance layer, transition layer, high-resistance layer, and anti-reflection layer is doped with vanadium dioxide at a molar ratio of 2% to 40% of the total amount. By employing a vanadium dioxide-doped selective absorption coating, the present invention achieves the desired performance of high absorption and low emission at low temperatures, which is beneficial for heat collection. Furthermore, the selective absorption coating achieves low absorption and high emission at high temperatures, effectively reducing the operating temperature of the heat collector tube when not in operation. This significantly improves the safety and reliability of the heat collector tube, particularly all-glass heat pipes.

The invention discloses a multifunctional terahertz chiral metasurface based on vanadium dioxide and graphene, the metasurface is formed by periodically arranging M * N metasurface units with multilayer structures in an array, the metasurface units are in M * N two-dimensional distribution, and both M and N are positive integers; the metasurface unit comprises a metal substrate, a first dielectric layer, a graphene layer, a second dielectric layer and a resonant layer unit which are sequentially arranged from bottom to top. According to the metasurface, by reasonably utilizing the phase change characteristic of VO2 and the tunability of graphene, efficient multifunctional response is achieved, and the problems that a traditional metasurface is few in function, single in regulation and control mode and low in efficiency are solved. The invention further provides a preparation method of the multifunctional terahertz chiral metasurface based on vanadium dioxide and graphene.

The invention provides an aqueous cadmium ion-vanadium dioxide battery as well as a preparation method and application thereof, and relates to the field of ocean energy storage. The battery comprises a negative electrode, a positive electrode, a diaphragm and an aqueous electrolyte, the negative electrode is metal cadmium or cadmium-based alloy; the active material of the positive electrode is metastable monoclinic phase vanadium dioxide; the diaphragm is a glass fiber diaphragm; the aqueous electrolyte is an aqueous solution containing cadmium salt; the total concentration of the cadmium salt in the aqueous electrolyte is 1-4 mol / L. The aqueous vanadium dioxide-cadmium metal secondary battery disclosed by the invention has the advantages of safe aqueous electrolyte system, high rate capability, ultra-long cycle life and the like, and has remarkable advantages when being applied to ocean energy storage.