120 results about "Single layer graphene" 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 method for characterizing physical properties of a single-layer graphene / semiconductor heterojunction. The method comprises the following steps: providing a physical property model about a single-layer graphene-semiconductor heterojunction, wherein influence factors comprise the change of Fermi level of single-layer graphene after the heterojunction is formed and the influence of an interface state on a formation position of a contact potential difference; extracting heterojunction electrical characteristics by using a Kelvin probe force microscope; the interface layer spacing is obtained; and importing the heterojunction electrical characteristics and the interface interlayer spacing into a physical characteristic model, and analyzing to obtain physical characteristics. According to the new theoretical model and the method for realizing the nondestructive characterization of the physical characteristics of the heterojunction by using the Kelvin probe microscope based on the theoretical model, the influence of the change of the Fermi level of the single-layer graphene and the interface state on the formation position of the contact potential difference is fully considered; key interface physical properties, especially built-in potential and depletion region characteristics which are crucial to device performance, can be accurately analyzed.

The invention discloses a high-first-effect fast-charging sodium ion battery hard carbon negative electrode material and a preparation method thereof, and belongs to the technical field of sodium ion batteries. The hard carbon negative electrode material comprises a hard carbon inner core and a conductive coating layer coating the surface of the hard carbon inner core, the hard carbon core is prepared from a carbon source through pre-carbonization and acid pickling treatment, and the carbon source comprises at least one of coconut shells and an epoxy resin carbon material; the conductive coating layer is a composition of glucose, single-layer graphene and water. The high-first-effect fast-charging sodium ion battery hard carbon negative electrode material disclosed by the invention has the advantages of low specific surface area, high first efficiency and high reversible capacity.

The invention relates to a photoelectric device for generating electric energy through conversion of ultraviolet light and near-infrared light, and discloses an ultraviolet photoelectric synapse / near-infrared photoelectric detection dual-mode photoelectric device. The dual-mode photoelectric device integrates dual functions of ultraviolet photoelectric synapse and near-infrared photoelectric detection: the ultraviolet photoelectric synapse function is realized based on a heterojunction formed by a single-layer graphene film and a wide bandgap perovskite Cs3Cu2I5 film, and B4PyMPM is doped in the Cs3Cu2I5 film to serve as an electron capture site, so that the electron capture capability is enhanced, and the photoelectric detection efficiency is improved. The performance of the ultraviolet photoelectric synapse device can be improved; a near-infrared photoelectric detection function is realized based on a heterojunction formed by a single-layer graphene thin film and n-type Ge, and the thickness of the Cs3Cu2I5 thin film is optimized, so that the Cs3Cu2I5 thin film becomes an antireflection layer of a 1550 nm near-infrared band, and the responsivity, the specific detection rate and other properties of a near-infrared photoelectric detection device are improved. The device disclosed by the invention is simple in structure and process, expensive instruments and equipment are avoided, and the preparation cost of the device is reduced.

The invention belongs to the technical field of biochemical sensing, and particularly relates to an optical-mechanical gas sensor based on a graphene annular microcavity. According to the sensor, a high-sensitivity and low-noise gas detection platform is constructed by combining a high-quality-factor annular microcavity with single-layer graphene; the sensor excites the boundary of the cavity to generate optical mechanical vibration by utilizing radiation pressure generated by propagation of photons in the microcavity; a phonon laser signal with stable frequency and extremely low noise is formed under the continuous action of the pump light; after target gas molecules are adsorbed by graphene, effective mass change of the microcavity is caused, measurable deviation of phonon laser frequency is caused, and therefore real-time high-sensitivity detection of gas concentration is achieved. The optical-mechanical interaction mechanism, the two-dimensional material gas adsorption characteristic and the microcavity optical regulation and control technology are fused, and the device has the advantages of being high in response speed, low in detection limit, easy to integrate and the like and is suitable for multiple scenes such as environment monitoring, biochemical analysis and industrial safety.

The invention discloses a remote epitaxial growth method of a gallium nitride film, which comprises the following steps: sequentially carrying out surface cleaning, argon etching, annealing treatment and surface nitriding treatment on a silicon substrate, and forming a Si3N4 layer on the surface of the silicon substrate; a single-layer graphene layer is formed on the surface of the side, provided with the Si3N4 layer, of the silicon substrate; growing a gallium nitride thin film on the single-layer graphene layer in a remote epitaxial manner; the silicon substrate is a monocrystalline silicon substrate; when the gallium nitride thin film is subjected to remote epitaxial growth, a nitrogen source with the flow of 8000-14000 sccm, a gallium source with the flow of 30-80 sccm and carrier gas are introduced under the condition that the temperature is 600-800 DEG C, a reaction is carried out for 5-30 min, and a nucleating layer grows; and introducing a nitrogen source with a flow rate of 5000-8000 sccm, a gallium source with a flow rate of 30-90 sccm and a carrier gas at a temperature of 1000-1200 DEG C, and carrying out a reaction for 150-200 min to obtain the gallium nitride thin film. By adopting the technical scheme provided by the invention, remote epitaxial growth of the gallium nitride film on the silicon substrate can be realized.

The application discloses an interlayer-coupled reduced graphene oxide (rGO) film, a preparation method and application thereof. Although single-layer graphene sheets have excellent intrinsic thermal conductivity, stacked graphene films have serious thermal anisotropy and poor out-of-plane thermal transport performance due to weak van der Waals interaction between layers. The application discloses a strategy for scalable preparation of an interlayer-coupled rGO film, which is connected by covalent carbon bonds between stacked layers. A representative 200 μm-thick film prepared by the strategy has in-plane and out-of-plane thermal conductivities of 1465±63 W·m ‑1 ·K ‑1 and 14.0±1.2 W·m ‑1 ·K ‑1 , respectively. Under an extreme heat flux of 1200 W·cm ‑2 , the film can reduce temperature by 110℃ within 20 s and has excellent cycle stability. The film has high thermal and electrical conductivity, and can realize fast, uniform and durable electrothermal heating, and can be applied to the field of advanced thermal management.

The invention provides a graphene transistor sensor and a preparation method and application thereof, and belongs to the technical field of biosensors. The graphene transistor sensor is used for noninvasive detection of depression and can detect depression-related markers in body fluids such as sweat, urine and saliva through noninvasive collection. According to the invention, a biosensing chip is constructed by using a graphene transistor array modified by gold nanoparticles, and simultaneous monitoring of multiple biomarkers can be realized by fixing different aptamers; the response speed and the sensitivity of the sensor are improved by utilizing the ultrahigh carrier mobility of the single-layer graphene with the quasi-single-crystal structure, and high-precision accurate detection is realized when the concentration of a biomarker is relatively low; the gold nanoparticle layer is used for fixing the aptamer of the target biomolecule, the coverage rate of the gold nanoparticles can be regulated and controlled by limiting the thickness of the gold film, more active sites are provided, the detection range can be expanded, and the detection requirement for continuously and dynamically monitoring the concentration change of the biomarker is met.

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 present invention relates to a photoelectric device that generates electrical energy by converting ultraviolet and near-infrared light. A dual-mode photoelectric device, ultraviolet photosynapse / near-infrared photodetection, is disclosed. This dual-mode device integrates both ultraviolet photosynapse and near-infrared photodetection functions: The ultraviolet photosynapse function is achieved through a heterojunction consisting of a single-layer graphene film and a wide-bandgap perovskite Cs3Cu2I5 film. The Cs3Cu2I5 film is doped with B4PyMPM as an electron-trapping site to enhance electron-trapping capability, thereby improving the performance of the ultraviolet photosynapse device. The near-infrared photodetection function is achieved through a heterojunction consisting of a single-layer graphene film and n-type Ge. The Cs3Cu2I5 film is optimized in thickness to serve as an antireflection layer in the 1550 nm near-infrared band, thereby improving the responsivity, specific detectivity, and other performance characteristics of the near-infrared photodetection device. The device structure and process of the present invention are simple, avoiding the need for expensive instrumentation and equipment, and reducing device manufacturing costs.

The invention relates to a method for epitaxial growth of single-layer graphene on a silicon carbide substrate, and belongs to the technical field of graphene preparation. The method comprises four steps of low-temperature high-vacuum preheating, polymer decomposition under vacuum, graphene growth and cooling. The growth substrate comprises two carbon source sheets of which the C surfaces are coated with polymers and a sheet to be grown, silicon carbide is adopted as the substrates of the carbon source sheet and the to-be-grown sheet, the substrates are placed in a growth graphite crucible, and the Si surface of the silicon carbide is placed downwards; the polymer is a solid carbon source. By adding a specific number of external carbon sources, the condition of rapid decomposition of the step edge can be effectively relieved, and the carbon concentration gradient during graphene growth is balanced, so that the growth of graphene is more inclined to quasi-equilibrium state growth. The graphene can be preferentially nucleated in the step, so that the condition of step coalescence caused by rapid decomposition of the edge of the step is inhibited, and the atomic-scale flat and clean silicon carbide-based epitaxial graphene can be obtained.

The present application relates to a gas sensing system and method for graphene side-polished fiber optic bridges (FBGs). The system comprises: an amplified spontaneous emission (ASE) light source, a polarization controller, a fiber coupler, a spectrum analyzer, a real-time demodulation system, and at least one graphene side-polished FBG. The graphene side-polished FBG comprises a single-layer graphene and a side-polished FBG polished by a polishing device, wherein the single-layer graphene is used to tune the center wavelength of the side-polished FBG. The ASE light source is used to generate multi-path broadband light that sequentially passes through the polarization controller, the fiber coupler, and at least one graphene side-polished FBG. The polarization controller is used to tune the polarization state of the broadband light to tune the loss of the graphene side-polished FBG. The spectrum analyzer is used to receive the broadband light transmitted by the graphene side-polished FBG and analyze it to obtain an analysis result. The real-time demodulation system is used to obtain the concentrations of multiple gases to be measured based on the analysis result. This method can achieve efficient and accurate detection of multiple gases.

The invention discloses an infrared detector sensitive element structure, a preparation method and an infrared detector, and is applied to the field of infrared detection.The infrared detector sensitive element structure comprises a first electrode, a pyroelectric functional layer and a second electrode; the pyroelectric functional layer is a polyvinylidene fluoride based copolymer thin film layer, and the polyvinylidene fluoride based copolymer thin film layer directly absorbs infrared light; the first electrode is arranged on the surface of one side of the pyroelectric functional layer, the second electrode is arranged on the surface of the other side of the pyroelectric functional layer, and the surface, provided with the second electrode, of the pyroelectric functional layer is an infrared light incident surface; the second electrode is a single-layer graphene electrode; and the single-layer graphene electrode has permeability to infrared light. The polyvinylidene fluoride-based copolymer film layer is used as a pyroelectric functional layer, and the single-layer graphene electrode is used as an electrode of an infrared light incidence side, so that the thickness of the functional layer can be reduced, and the functional layer is enabled to directly dominate absorption of infrared radiation, thereby reducing the heat capacity of the device, and improving the response sensitivity and response speed of the device.

A silicon-phase change material hetero-integrated waveguide structure includes a silicon flat plate layer and a phase change material deposited on the silicon flat plate layer. A non-volatile waveguide phase shifter includes a base layer, a hetero-integrated waveguide structure and a silicon waveguide mode spot conversion structure fixed on the base layer, two ends of the hetero-integrated waveguide structure are symmetrically connected to the silicon waveguide mode spot conversion structure; the silicon waveguide mode spot conversion structure includes two silicon waveguides with narrow-to-wide and an ridge waveguide with wide-to-narrow arranged in axial symmetry; an aluminum oxide film is covered on the phase change material, a single-layer graphene is on the aluminum oxide film, and a metal layer is on the single-layer graphene, the metal layer includes two metal electrodes. The single-layer graphene forms ohmic contact with the metal electrodes, current passes through the graphene to generate heat, the heat is conducted through the aluminum oxide film below the single-layer graphene to provide heat required for phase change of the low-loss phase change material. The phase shifter has the advantages of compact structure, low insertion loss, small driving voltage, low phase change power consumption, non-volatile phase adjustment, etc. and can be used as a core optical path regulation device in an integrated optoelectronic chip.

The invention discloses a graphene flexible terahertz wave detector and a preparation method thereof. The detector comprises a substrate layer and a graphene layer, the substrate layer is of a flexible insulation structure, the graphene layer is located above the substrate layer, the graphene layer is a single-layer graphene film, and the two ends of the graphene layer are connected with a source metal electrode and a drain metal electrode of asymmetric electrodes in a covering mode respectively. The graphene flexible terahertz wave detector provided by the invention has good flexibility and stability, supports recognizable and repeatable terahertz response, and can expand the response wavelength range to ultraviolet to millimeter wave frequency bands. And under conformal attachment with a flexible curved surface, high-resolution terahertz wave imaging of a composite material object and a hidden object is realized.

This invention discloses a graphene and boron nitride composite reinforced AM60B magnesium alloy matrix composite material, which is composed of the following raw material components by weight percentage: GR powder 1.6-2.5%, c-B3N4 particles 1-10%, and the balance being semi-solid AM60B magnesium alloy particles for injection molding, with the sum of the weight percentages of the above components being 100%. This material solves the interface problem between single-layer graphene GR and the α-Mg grains of the magnesium alloy matrix, avoiding the problem of microcracks at the interface. It also discloses a method for preparing structural parts using arc additive manufacturing, employing the aforementioned graphene and boron nitride composite reinforced AM60B magnesium alloy matrix composite material as raw material.

The invention provides a photoelectric conversion method and application thereof. The photoelectric conversion method comprises the following steps: enabling light with a selected wavelength to irradiate a heterojunction device so as to enable the heterojunction device to generate light current and / or light potential difference; wherein the heterojunction device is composed of a GaN layer and single-layer graphene (SLG) which are in direct contact, and the contact face of the GaN layer and the SLG is the N face or the r face of GaN. Influences of different types of GaN lattice orientations on the photoelectric characteristics of the GaN / SLG heterojunction structure are deeply studied, a preferable application direction of constructing the GaN / SLG heterojunction structure by taking an N surface or an r surface as a contact surface for photoelectric conversion is provided, dark current can be obviously reduced, photoelectric conversion efficiency, responsivity, maximum output power and the like can be obviously improved, and the GaN / SLG heterojunction structure can be widely applied to the field of photoelectric conversion. A solution with excellent performance is provided for the application of the GaN / SLG heterojunction structure in the photoelectric conversion field, such as a photoelectric detector, a solar cell or a photoelectric artificial synapse.

The application relates to a method for improving spin injection efficiency by using a buffer layer, relating to spintronics. A long strip-shaped single-layer graphene is prepared on a silicon substrate, a double-layer h-BN is prepared and transferred onto the single-layer graphene as a tunneling layer, PMMA is spin-coated, a ferromagnetic electrode shape is exposed by using an EBL system, and development is carried out after the exposure is completed; the sample is placed into an electron beam / thermal evaporation composite plating film system, a low-melting-point metal indium is pre-evaporated as a buffer layer by using a thermal evaporation method, cobalt is electron beam evaporated as a ferromagnetic electrode, an In / Co miscible alloy interface is formed by annealing at 200 DEG C under an argon atmosphere for 1 h, and a spin valve device with a buffer layer is obtained. The method forms a lossless interface of a ferromagnetic electrode layer-buffer layer-tunneling layer, and spin injection efficiency is improved. The method is easy to realize, low in cost, low in operation difficulty and technical requirement, and beneficial to large-scale industrial application; the method is very good in universality, and can be popularized to other spin electronic devices with a tunneling layer to improve the spin injection efficiency of the devices.

The invention provides a preparation method of a defective graphene smoke suppression and toxicity reduction protective coating material, which comprises the following steps: mixing single-layer graphene powder and melamine, and operating in an inert gas atmosphere according to the following heating procedure: heating from room temperature to 750 DEG C, preserving heat for 1-3 hours, heating from 750 DEG C to 1150 DEG C for heat treatment, and naturally cooling to obtain defective graphene powder; the defective graphene powder is dispersed in deionized water and stirred uniformly, and the PU foam is pretreated and then immersed in the defective graphene dispersion liquid. And fixing the graphene powder on the pretreated PU foam, and carrying out vacuum drying to obtain the defective graphene smoke suppression and toxicity reduction protective coating material. Compared with a common flawless graphene material, the performance of the coating is improved by 34.63%, the flame retardant and smoke suppression performance is remarkably improved through the mechanisms of enhancing the quality of a carbon layer, capturing free radicals, catalyzing carbon forming and the like, the environment cannot be polluted in the preparation process, and the coating is green and environmentally friendly. The stability and durability of the coating in a complex environment are facilitated.

The invention provides a method and a device for measuring the transverse spatial resolution of a confocal Raman microscope, and relates to the technical field of optical measurement and micro-spectrum. The method comprises the following steps: positioning a linear edge area on a single-layer graphene sample by using a confocal Raman microscope, and preparing the single-layer graphene sample on a silicon oxide substrate; determining a linear scanning path and a scanning step length from the exposed area of the substrate to the sample area in the positioned area of the linear edge along the direction vertical to the linear edge by using a confocal Raman microscope; in the moving process of the single-layer graphene sample, determining a plurality of scanning points on the linear scanning path based on the scanning step length, and collecting a Raman spectrum signal of each scanning point; and determining the transverse spatial resolution of the confocal Raman microscope based on the Raman spectrum of each scanning point. By adopting the method provided by the invention, the accuracy of the transverse spatial resolution of the confocal Raman microscope can be improved.

The embodiment of the invention discloses a transition metal atom doped graphene / Ti < 3 > C < 2 > O < 2 > heterojunction, a construction method and application. The method comprises the following steps: selecting a single-layer graphene supercell and a single-layer Ti < 3 > C < 2 > O < 2 > supercell, and constructing a graphene / Ti < 3 > C < 2 > O < 2 > heterojunction; removing two adjacent carbon atoms on the graphene layer of the graphene / Ti3C2O2 heterojunction to form a vacancy enclosed by four carbon atoms, and replacing the four carbon atoms forming the vacancy with four nitrogen atoms; the method comprises the following steps: doping a transition metal single atom at the center of four nitrogen atoms to obtain a transition metal atom doped graphene / Ti < 3 > C < 2 > O < 2 > heterojunction which is marked as TMN < 4-> G / Ti < 3 > C < 2 > O < 2 >; the adsorption performance of the TMN4-G / Ti3C2O2 on the lithium polysulfide is evaluated; the catalytic performance of the TMN4-G / Ti3C2O2 on the sulfur reduction reaction is evaluated; the dissociation performance of the TMN4-G / Ti < 3 > C < 2 > O < 2 > on Li2S molecules is evaluated; based on the adsorption performance, the catalytic performance and the dissociation performance of TMN4-G / Ti3C2O2, a transition metal atom doped graphene / Ti3C2O2 heterojunction suitable for being used as a lithium-sulfur battery positive electrode material is selected.

The application discloses a manufacturing method of a graphene back gate electrode terahertz wave modulator, which comprises the following steps: growing and transferring a first layer of graphene; photoetching a graphene back gate pattern; photoetching a back gate electrode pattern and preparing a back gate electrode; growing a medium layer; growing and transferring a second layer of graphene; photoetching a graphene strip pattern and preparing a graphene strip; photoetching an open resonant ring pattern and preparing an open resonant ring metal. The application discloses a terahertz wave modulator, which comprises a high-resistance substrate, a graphene back gate electrode layer and a high-K gate medium layer which are sequentially bonded from bottom to top; the high-K gate medium layer is provided with an array of graphene strips and an open resonant ring metal, the open resonant ring metal is arranged around the graphene strips and is in physical contact with the graphene strips. The application constructs a back gate electrode on a single layer of graphene, thereby getting rid of the absorption of a conductive substrate to terahertz waves and effectively improving the modulation efficiency of the terahertz wave modulator to terahertz waves.

The invention relates to the technical field of water electrolysis and chlor-alkali industry electro-catalysis hydrogen evolution, in particular to a preparation method of a controllable carbon layer loaded monatomic titanium-based electrode. The method comprises the following steps: (1) respectively placing a solid-phase carbon source and a titanium substrate subjected to acid treatment in a gas inlet and a heating temperature zone of a tubular furnace; (2) introducing inert gas and a certain proportion of hydrogen, heating the tubular furnace to 600-1200 DEG C, and keeping the temperature for 0-300 minutes; after natural cooling, the carbon-coated titanium-based material is obtained; and (3) loading monoatomic single-layer, few-layer and multi-layer carbon-coated titanium-based electrodes on the carbon-coated titanium-based material through a post-deposition method. According to the invention, an acid-resistant substrate material is selected to prepare a carbon-supported monatomic electrode, and through the solution of optimizing a catalytic material, improving growth conditions, increasing the utilization rate of noble metal atoms and the like, uniform distribution and efficient utilization of noble metal atoms on single-layer graphene are expected to be realized, and a high-performance monatomic water electrolysis catalyst is designed and prepared.

The application provides a method and device for measuring lateral spatial resolution of a confocal Raman microscope, and relates to the field of optical measurement and microscopic spectroscopy technology. The method comprises the following steps: positioning a region of a straight edge on a single-layer graphene sample by using a confocal Raman microscope, wherein the single-layer graphene sample is prepared on a silicon oxide substrate; determining a straight scanning path and a scanning step in a direction perpendicular to the straight edge from a bare region of the substrate to a sample region in the region of the straight edge which has been positioned by using the confocal Raman microscope; determining a plurality of scanning points on the straight scanning path based on the scanning step in the process of moving the single-layer graphene sample, and collecting Raman spectrum signals of the scanning points; and measuring the lateral spatial resolution of the confocal Raman microscope based on the Raman spectrum of each scanning point. By using the method provided in the application, the accuracy of the lateral spatial resolution of the confocal Raman microscope can be improved.

The invention relates to the technical field of heat conduction materials, and particularly discloses a high-heat-conductivity graphene heat conduction cable and a preparation method thereof.The high-heat-conductivity graphene heat conduction cable comprises a strip-shaped flexible heat conduction belt and metal components welded to the two ends of the flexible heat conduction belt and used for being connected with a heating device; the heat conductivity of the flexible heat conduction belt is 500-2500W / (m.K); the flexible heat conduction belt is formed by stacking and connecting a plurality of graphene heat conduction sheets, and the graphene heat conduction sheets comprise modified graphene, nanometer aluminum oxide particles and nanometer silicon carbide particles. The modified graphene is obtained by modifying graphene oxide with a liquid crystal modifier. According to the high-thermal-conductivity graphene heat-conducting cable, the structure of the single-layer graphene heat-conducting layer is optimized while the problem of connection of the multiple graphene heat-conducting layers is solved, and the thermal conductivity of the single-layer graphene heat-conducting layer in the longitudinal direction and the transverse direction is improved; moreover, the graphene heat-conducting layer is combined with the metal component, so that the use scene of the heat-conducting cable is enlarged, and the applicability of the heat-conducting cable is effectively improved.

The invention discloses a preparation method of a graphite material with low porosity and high bending strength. The preparation method comprises the following steps: S1, calcining one or two of pitch coke or petroleum coke to obtain calcined coke, crushing, and screening to obtain nanoscale calcined coke powder; s2, mixing nanoscale calcined coke powder, sulfur powder and single-layer graphene powder, and adding kerosene as a wet mixing medium to obtain a uniform mixture; s3, carrying out atomization granulation on the mixture obtained in S2 to form a nearly spherical particle mixture, and carrying out three-way unequal cold press molding and baking to obtain a green body; s4, carrying out air pressure roasting on the green body under vacuum and inert gas protection, and cooling to room temperature to obtain a graphite roasting product; s5, cleaning the surface of the graphite roasting product, and performing dipping treatment to obtain a dipped product blank; and S6, carrying out graphitization treatment on the impregnated product blank to obtain the graphite material. According to the invention, the grain size is reduced while graphite pores are reduced, and the prepared graphite material has good mechanical properties.

The application discloses a graphene-coated surface saturable absorber device of a multimode optical fiber with an internal microstructure, which adopts a mixed structure of graphene and a graded-index multimode optical fiber. The saturable absorber device comprises a first single-mode optical fiber, a mixed structure based on a multimode optical fiber, and a second single-mode optical fiber. The mixed structure based on the multimode optical fiber is composed of a tapered graded-index multimode optical fiber with an internal microstructure and a single-layer graphene film. The graded-index multimode optical fiber is first subjected to a micro-tapering treatment, then a microstructure is inscribed in the core inside the taper waist, then the graphene film is coated on the surface of the taper waist of the optical fiber, and finally the single-mode optical fibers are fused at both ends of the multimode optical fiber. The saturable absorber combines the nonlinear multimode interference effect in the multimode optical fiber and the saturable absorption characteristics of graphene, can perform secondary compression on the pulse width of a high-energy pulse, and thus obtains an ultrashort pulse. The application has the advantages of a solid structure, strong stability, a high damage threshold and the like, and provides an effective technical means for obtaining a stable ultrashort pulse mode locking.

The invention relates to the technical field of metasurface electro-optical devices, in particular to a low-loss mid-infrared electro-optical modulator based on graphene and ITO and a preparation method thereof, SiO2, Al2O3, graphene, TiO2 and ITO are sequentially arranged in the electro-optical modulator from bottom to top, and Si is embedded in SiO2 to serve as a central waveguide. Single-layer graphene and ITO with the thickness of 30 nm are placed in a staggered mode to form a heterojunction, change of carriers in the Si waveguide is caused, and then modulation of the change of effective refraction in the Si waveguide is achieved; besides, the graphene and the ITO form a parallel-plate capacitor, the switching energy of the modulator is reduced, high modulation efficiency is achieved, and finally, metal electrodes are placed on the graphene and the ITO respectively, so that voltage directly controls heterojunction. According to experimental verification, a high extinction ratio is achieved under low insertion loss, and multi-rate modulation can be achieved.

The application discloses a kind of optical nerve unit device, the construction method of deep learning optical nerve network, it is related to neural network technical field, including contact metal electrode, graphical graphene array, dielectric layer film and substrate, the graphical graphene array is contacted with dielectric layer film formed on substrate, the contact metal electrode is contacted with graphical graphene array and is used to generate electric field with substrate, regulate device output optical signal as the input weight of synapse, the graphical graphene array includes graphene and infrared light source wave, the graphene is single-layer graphene, the graphical graphene array unit is periodic strip, the beneficial effects of the application are: compared with other materials, graphical graphene is due to high carrier density and support surface plasmon propagation, provides an incomparable advantage, i.e. in room temperature to terahertz range in the wavelength of mid-infrared can be in situ dynamically tuned by using gate voltage.

The present invention relates to the design, construction and application of a zirconia inorganic molecularly imprinted acetaminophen electrochemical transistor sensor. The electrochemical transistor sensor includes a source electrode, a drain electrode and a gate electrode; both the source electrode and the drain electrode are disposed on a gold electrode with a chromium layer at the bottom layer, and the channel between the source electrode and the drain electrode is a single-layer graphene; in order to improve the sensitivity and accuracy of the transistor sensor in detection, the present invention uses acetaminophen as the target molecule, a gold nanoparticle / graphene composite material as the imprinting carrier, and zirconium oxychloride as the inorganic functional monomer to form a zirconia-gold nanoparticle / graphene / molecularly imprinted composite material on the surface of a glassy carbon electrode, and uses it as the gate electrode of the transistor sensor. The present invention constructs a molecularly imprinted electrochemical transistor sensor with specific selectivity for acetaminophen, which has the characteristics of high sensitivity, low detection limit and high selectivity, and can achieve accurate determination of acetaminophen in a complex urine environment.