262 results about "Vanadium dioxide" patented technology

The invention discloses a dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber which comprises M * N terahertz absorption units of a multi-layer structure, the M * N terahertz absorption units of the multi-layer structure are distributed in an M * N two-dimensional mode, and M and N are positive integers. Each terahertz absorption unit with the multi-layer structure comprises a metal substrate, a dielectric layer and a resonance layer which are sequentially arranged from bottom to top; the dielectric layer and the metal substrate are square and have the same side length; the resonance layer comprises a single-layer graphene layer with a hollow cross, and a solid cross-shaped vanadium dioxide layer is embedded in the hollow part of the single-layer graphene layer with the hollow cross; and the appearance of the single-layer graphene layer with the hollow cross is cross-shaped. The absorber can be dynamically tuned, has the characteristic of polarization insensitivity, and can keep stable absorption in an incidence angle range of 0-60 degrees. The invention further discloses a preparation method of the dual-frequency / broadband switchable dynamic tuning metamaterial terahertz absorber.

The invention discloses a composite thermochromic window with a dual-band dynamic regulation and control function. The composite thermochromic window comprises a first transparent substrate, a tungsten-doped vanadium dioxide film, a second transparent substrate and a hydrogel layer. The tungsten-doped vanadium dioxide film is deposited on the upper surface of the first transparent substrate, and the phase transition temperature is 25-32 DEG C; the hydrogel layer is thermo-sensitive poly (N-isopropylacrylamide) and is encapsulated between the two transparent substrates, and the low critical phase transition temperature is 32 + / -2 DEG C. When the temperature is lower than 25 DEG C, the infrared transmittance of the tungsten-doped vanadium dioxide film is larger than or equal to 75%, and the visible light scattering rate of the hydrogel layer is smaller than or equal to 10%; when the temperature is higher than 32 DEG C, the near-infrared transmittance of the tungsten-doped vanadium dioxide film is reduced to the minimum value, and the visible light scattering rate of the hydrogel layer is increased to 35% or above. Compared with the prior art, the system and the method have the advantages that dual-band dynamic regulation and control of visible light and near-infrared light are achieved, the indoor photo-thermal environment can be automatically regulated according to the environment temperature, and the building energy utilization efficiency is improved.

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 provides a coding metasurface with terahertz wave absorption and reflection functions and application, the coding metasurface comprises at least one coding unit arranged in an array, each coding unit comprises a top resonance layer, a dielectric layer and a metal reflection layer which are sequentially arranged from top to bottom, the top resonance layer comprises a graphene resonance layer and a vanadium dioxide phase change layer, and the dielectric layer comprises a dielectric layer and a metal reflection layer. The graphene resonance layer comprises square graphene, the vanadium dioxide phase change layer comprises a square vanadium dioxide outer ring and a vanadium dioxide strip embedded in the vanadium dioxide outer ring, the vanadium dioxide outer ring is located on the inner side of the graphene, and the square edge of the vanadium dioxide outer ring and the square edge of the graphene are arranged in parallel at an interval; wherein the vanadium dioxide strips are arranged at the diagonal positions of the vanadium dioxide outer ring and are arranged at intervals with the vanadium dioxide outer ring, the advantages of a wave-absorbing metasurface and a reflection coding metasurface are integrated, and the signal generation power of 6G communication is greatly optimized.

The invention discloses a vanadium dioxide-based spin coupling and decoupling dynamic switching metasurface. The unit structure of the metasurface is divided into three reflecting layers; a dielectric layer; the metal layer is of an S-shaped structure and comprises a rectangle in the middle and circular arcs at the two ends, the rectangle is made of gold, and the circular arcs are made of vanadium dioxide; when vanadium dioxide is in a metal state, adjusting an opening angle alpha between the arc and the rectangle and a rotation angle theta of the metal layer around an X axis, and realizing decoupling of left-handed polarized light and right-handed polarized light through combination of a PB phase and a transmission phase; when vanadium dioxide is in an insulated state, the PB phase is regulated and controlled only by rotating the angle theta, and coupling of left-handed polarized light and right-handed polarized light is achieved. Compared with other coding metasurfaces, the modulation mode is simpler, the design is more flexible, the functions are more diversified, the defect that the function of the metasurface is fixed is overcome, the coupling characteristic and the decoupling characteristic of left-handed and right-handed polarized light are integrated together, and the application prospect of a coding metasurface device is expanded.

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 invention belongs to the technical field of building glass and coating materials thereof, and discloses a one-step chemical synthesis method of W-VO2 (M) nano-particles and application of the W-VO2 (M) nano-particles in thermochromic smart windows.The method comprises the steps that firstly, ammonium metavanadate, hydrazine hydrate and ammonium metatungstate serve as raw materials, tungsten-doped M-phase vanadium dioxide nano-particles are chemically synthesized through a one-step hydrothermal method, and the tungsten-doped M-phase vanadium dioxide nano-particles are prepared; the obtained W-VO2 (M) nanoparticles are high in crystallinity, small in particle size (10-40nm), high in purity and low in phase change temperature; then, by taking a polyvinylpyrrolidone material as a parent material, uniformly distributing the W-VO2 (M) nanoparticles in PVP (Polyvinyl Pyrrolidone) to form a uniformly dispersed thin film; according to the application of the W-VO2 (M) nanoparticles in the thermochromic intelligent window, not only can high visible light transmittance be obtained, but also the solar energy regulation and control capability of the W-VO2 (M) nanoparticles can be improved, and the application of the W-VO2 (M) nanoparticles in the fields of the thermochromic intelligent window and radiation refrigeration is further promoted.

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.

The invention relates to the technical field of terahertz metamaterial devices, in particular to an ultra wide band / double narrow band switchable terahertz wave absorber based on vanadium dioxide and sensing application. The wave absorber is formed by periodically arranging and combining a plurality of metamaterial square structure units, and no gap exists between adjacent periodic units. Each metamaterial square structure unit is composed of six layers from top to bottom, namely a VO2 resonance layer, a photonic crystal plate dielectric layer, a VO2 thin film, a metal resonance layer, a polycrystalline silicon dielectric layer and a gold substrate. The reversible phase change process of vanadium dioxide from a metal state to an insulation state is realized through external excitation (light, temperature and voltage). When vanadium dioxide is in a metal state, the terahertz ultra-bandwidth absorption function is achieved, when vanadium dioxide is in an insulated state, the terahertz wave double-narrow-band absorption function is achieved, and conversion between the ultra-wide band and the double narrow bands of the wave absorber is achieved. According to the terahertz wave absorber, the ultra-wideband / dual-narrowband conversion function of terahertz wave absorption can be achieved on one device, the defects that an existing terahertz wave absorber is complex in structure and the absorption characteristic is fixed once the terahertz wave absorber is manufactured are overcome, and the sensing function application of a single narrowband in the terahertz wave absorber is researched.

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.

A phase shifter including a 90 degree hybrid circuit having two reflection ends, a varactor having a variable capacitance layer made of vanadium dioxide and disposed at the reflection end of the 90 degree hybrid circuit, and a stub connected to the reflection end of the 90 degree hybrid circuit via the varactor.

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.

A reconfigurable millimeter wave filter, comprising first and second transmission line resonators and first and second shunt switches. The first and second transmission line resonators can comprise first ends electrically coupled to an input and second ends electrically coupled to a ground. The first shunt switch can be disposed within a length of the first transmission line resonator and be electrically coupled to the ground. The second shunt switch can be disposed within a length of the second transmission line resonator and be electrically coupled to the ground. The first and second shunt switches can comprise at least one phase change material, wherein application of thermal energy to the at least one phase change material of the first and second shunt switches can alter a path length of an input signal propagating along the first and second transmission lines.

The invention discloses a dynamic tunable chiral terahertz broadband absorber based on vanadium dioxide, the absorber is formed by periodically arranging M * N absorption units of a multilayer structure in an array, the absorption units are in M * N two-dimensional distribution, and both M and N are positive integers; the absorption unit comprises a metal substrate, a dielectric layer and a resonance layer which are sequentially arranged from bottom to top; the metal substrate and the dielectric layer are rectangular; the resonance layer comprises a J-shaped metal patch, and an inverted-T-shaped vanadium dioxide patch is arranged at one end of the J-shaped metal patch. The terahertz chiral absorber can have a circular dichroism (CD) value larger than 0.8 within the range of 5.36-7.69 THz, the mirror image enantiomer of the terahertz chiral absorber can also achieve a CD spectrum opposite to the mirror image enantiomer, and the terahertz chiral absorber has the advantages of being high in CD, dynamically tunable and simple in structure. In addition, the invention also discloses a preparation method of the dynamic tunable chiral terahertz broadband absorber based on vanadium dioxide.

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 a Malus metasurface-based dynamic optical differentiator and a design method thereof, the dynamic optical differentiator comprises a metasurface array and a grating structure, and the metasurface array is formed by a plurality of nano brick structure units on the same plane; each nano brick structure unit comprises a silicon substrate, a silicon dioxide layer and a silicon nano brick which are sequentially arranged from bottom to top; a layer of grating structure composed of vanadium dioxide is tightly attached to the bottom of the substrate, and the state of the vanadium dioxide is changed by controlling the temperature, so that dynamic switching between first-order differential and second-order differential is completed, that is, the vanadium dioxide is in a medium state before phase change, the first-order differential is completed, and the vanadium dioxide is in a metal state after phase change, and the second-order differential is completed. The functions of a first-order differentiator and a second-order differentiator can be achieved without additional optical elements, and the vanadium dioxide material is introduced to achieve dynamic regulation and control of functions.

The present invention discloses a recyclable and remoldable transparent intelligent microwave absorbing material, its preparation method and application, belonging to the field of novel electromagnetic protection materials. In the present invention, a polymer matrix material is dissolved in a solvent, and then an appropriate amount of ionic liquid and vanadium dioxide nanoparticles are added thereto and mixed uniformly. Then, the mixed solution is poured into a mold, and after drying, hot pressing is carried out to obtain the recyclable and remoldable transparent intelligent microwave absorbing material. The recyclable and remoldable transparent intelligent microwave absorbing material not only can be recycled and remolded, has economic value and environmental protection significance, but also has good transparency, excellent high temperature resistance, as well as intelligent microwave absorption and color change properties, and has high application value in military or civilian transparent electromagnetic protection fields such as fighter cockpit glass, warship portholes and transparent electromagnetic shielding rooms.

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.

A phase shifter including a 90 degree hybrid circuit having two reflection ends, a variable stub having a line formation layer made of vanadium dioxide and extending from each of the two reflection ends, and a ground pattern formed with a groove in which the variable stub is disposed and connected to a side end of the variable stub disposed in the groove.

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 invention discloses a hydrophobic thermochromic nano core-shell structure coating and a preparation method and application thereof.The preparation method of the hydrophobic thermochromic nano core-shell structure coating comprises the steps that trimethoxysilane and deionized water are mixed and stirred, and a stock solution is prepared; adding the tungsten-doped vanadium dioxide nanoparticles into an alcohol-water mixed solution of deionized water and absolute ethyl alcohol, and stirring to prepare a vanadium dioxide solution; adding the stock solution and the vanadium dioxide supernatant into deionized water, adding an ammonia water solution, carrying out ultrasonic treatment, and adding acetone to terminate the reaction; centrifuging to obtain a core-shell nanoparticle solution sample; adding waterborne polyurethane into the sample, stirring, spin-coating and drying to obtain a color-changing coating; according to the coating, material oxidation is avoided by adopting a VO2 coated SiO2 core-shell structure, so that the intelligent window has thermochromic performance and hydrophobic performance at the same time, the heat transfer coefficient is increased, and a new thought is provided for promoting development of a spacecraft heat management technology.

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 invention discloses an optical performance optimization method for PVB (Polyvinyl Butyral) with vanadium dioxide particles. The method comprises the following steps: setting initial values of characteristic parameters of a PVB film and emission parameters of optical signals; calculating optical parameters of the optical signal after each collision with the vanadium dioxide particles in the PVB film to obtain the collision frequency and the displacement value of the optical signal; calculating the collision times and the displacement value after the optical signal collides with the vanadium dioxide particles for multiple times in the PVB film, and determining one or more of the transmissivity, the reflectivity and the absorptivity of the PVB film to the optical signal so as to obtain the optical signal transmission performance of the PVB film; and changing one or more values in the characteristic parameters of the PVB film so as to enable the optical signal transmission performance of the PVB film to meet the specified requirements. By means of the method, the optimal manufacturing parameters of the PVB film can be rapidly obtained based on the set standard, and therefore efficient heat regulation and control windshields can be manufactured conveniently.

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.

The invention discloses a magnetron sputtering process and a coating device for improving the content of vanadium dioxide in films, a first film and a second film are deposited on the surface of a substrate through two times of magnetron sputtering, and oxygen flows of process gases used twice are different, so that an oxygen-enriched vanadium oxide film and an oxygen-deficient vanadium oxide film are prepared; the surface-coated substrate is put into an annealing cavity, the temperature in the annealing cavity is maintained at 150-350 DEG C, oxygen atoms can obtain enough energy to overcome lattice potential barriers and start to move at the temperature, the oxygen atoms can spontaneously diffuse from a high-concentration oxygen-enriched layer to a low-concentration oxygen-deficient layer, and finally uniform distribution of oxygen elements in the thin film is achieved; and finally, a film with relatively high vanadium dioxide content and uniform components is formed.