20 results about "Electron diffraction" patented technology

This invention discloses a method for identifying the origin of quartz based on multimodal signal fusion using scanning electron microscopy (SEM). It utilizes only one SEM equipped with an energy dispersive spectroscopy (EDS) probe, a cathodoluminescence (CAT) probe, and a backscattered electron diffraction (BSE) probe. By comprehensively employing multiple indicators, including the coefficient of variation of CL band width (a), the Al-Ti influence coefficient (b), the lattice orientation difference influence coefficient (c), and the relative gravity coefficient of inclusion type (d), the method determines whether a quartz sample is of hydrothermal or metamorphic origin. This invention achieves rapid and accurate identification of the origin of quartz.

A positive electrode includes a positive electrode active material that includes a lithium nickel-based composite oxide and is in a form of a single particle. A ratio of a volume cumulative average particle diameter (D50) of the positive electrode active material measured using a particle size analyzer to a grain size of the positive electrode active material measured using backscatter electron diffraction after ion milling of the positive electrode is about 1.6 to about 1.8.

The invention discloses a film layer monitoring device and epitaxy equipment, the film layer monitoring device is used for vapor phase epitaxy equipment, and the film layer monitoring device comprises an electron beam emission mechanism which comprises an electron emission assembly and an electron channel; the electron emitting assembly is used for generating electron beams; an inlet of the electron channel is communicated with an emitting end of the electron emitting assembly, and an outlet of the electron channel is arranged at a position close to the edge of the wafer; electron beams generated by the electron emitting assembly are glanced to the surface of the wafer through the electron channel so as to be diffracted on the surface of the wafer to form diffracted electron beams; a receiving end of the electron beam receiving mechanism is located in the epitaxial chamber; the electron beam receiving mechanism is configured to capture diffracted electron beams and convert the diffracted electron beams into quantizable signals; the electron beam receiving mechanism is further configured to perform in-situ monitoring on the wafer film layer based on the quantizable signal. The crystal quality and the deposition thickness of the film layer can be monitored in situ in the film growth process, and high-quality imaging of electron diffraction signals can be ensured.

The application relates to the field of crystal structure symmetry classification and retrieval, and specifically discloses a crystal structure symmetry determination and retrieval method using electron diffraction, which comprises the following steps: a multi-view selected area electron diffraction data input module is used to acquire a two-zone axial diffraction spectrum and perform pretreatment; a symmetry feature coding module is used to extract a single-view descriptor through a double-branch convolutional neural network, to obtain a material descriptor through view pooling fusion; a hierarchical symmetry classification module is used to realize hierarchical classification of crystal systems and space groups, and to guarantee the logic of the results through consistency constraints; a high-dimensional feature embedding and database construction module is used to standardize crystal structure files, to generate descriptors, and to construct a vector database; and a constrained structure retrieval module is used to combine the classification results and user constraints to filter candidate structures, and to complete retrieval through cosine similarity. The application solves the problems of poor generalization, insufficient multi-view feature fusion and inability to associate a crystal library in the prior art, and realizes full-process automation of crystal structure symmetry classification and retrieval.

The application provides a spatial orientation high-resolution mapping method and system for single crystal EBSD, comprising the following steps: S1: collecting diffraction signals of a single crystal sample by a backscattering electron diffraction technology to obtain Euler angle parameters and corresponding spatial coordinates of pixel points; S2: converting the obtained Euler angle parameters into polar angle parameters according to a crystallographic coordinate transformation relationship, and establishing a corresponding relationship between the polar angle parameters and the spatial coordinates; S3: discretizing continuous polar angle information into polar angle grid units; S4: mapping the polar angle parameters of each pixel point to the polar angle grid units to realize attribution determination and partition aggregation of the pixel points in an angle space; and S5: explicitly representing spatial distributions corresponding to each angle unit to establish a mapping relationship between the polar angle and the spatial coordinates.

The application discloses a high-speed quantitative measurement method for microgram-level material gas adsorption and desorption process, and realizes in-situ measurement of gas layer thickness change in a sealed microcavity in a transmission electron microscope on the basis of a sample position measurement method based on micro-area electron diffraction Thon ring, realizes in-situ high-speed measurement of gas capacity released or absorbed by a sample by establishing a relationship curve between the gas layer thickness and the microcavity gas pressure, and achieves high-speed and quantitative measurement of the microgram-level or nanogram-level material gas adsorption and desorption process in a millisecond or even faster scale. The difficulty of directly measuring the gas pressure in-situ in the gas microcavity is solved for the first time, and the method has important significance for studying the gas charging and discharging process of trace materials by means of the electron microscope sealed microcavity in-situ technology. In addition, the method has very high sensitivity and can realize high-precision measurement of sub-nanometer-level gas layer thickness change (<10 ‑9 m) and millibar-level gas pressure change (<10 ‑1 Pa) in the electron microscope microcavity.

The invention provides a substance detection system and method and diagnostic equipment, and belongs to the technical field of electron diffraction, and the substance detection system comprises an electron emission module, a laser emission module and a detection module. The electron emission module comprises an electron emitter and a grid electrode. The electron emission module is used for emitting electronic pulses to the to-be-detected sample in the excited state. The grid electrode is arranged on the periphery of the electron emitter and regulates and controls electron beams emitted by the electron emitter. The laser emission module is used for emitting laser pulses to a to-be-detected sample, so that the to-be-detected sample reaches an excited state. And the detection module is used for detecting detection signals obtained by the laser emission module and the electron emission module acting on the to-be-detected sample. The electronic emission module, the laser emission module and the detection module are arranged to be in mutual time synchronization. According to the substance detection system and method provided by the invention, the dynamic process of different substances in different time scales can be represented, and the technical problem that the application range of a traditional system is narrow is solved.

The utility model discloses a backscattered electron diffraction analysis sample fixing device which comprises a main mounting assembly, an auxiliary mounting inclined plane is arranged on the main mounting assembly, a sample limiting assembly is arranged on the auxiliary mounting inclined plane, a first auxiliary plate is arranged on the inner side of the sample limiting assembly, and a second auxiliary plate is arranged on the outer side of the sample limiting assembly. A plurality of first sample pressing sheets are arranged on the first auxiliary plate, a second auxiliary plate is arranged on the outer side of the main mounting assembly, and a plurality of second sample fixing plates are arranged on the second auxiliary plate. The sample fixing device has the advantages that the sample fixing device is ingenious in structural design, high in practicability and convenient to operate, when the sample fixing device is used, a sample can be rapidly fixed to an electron microscope table, it is avoided that substances such as conductive adhesive and elargol are used for fixing the sample, the sample fixing stability is high, and by means of the sample fixing device, the sample fixing effect is good. The stability of sample clamping is effectively improved, and the accuracy of sample analysis and test results is also effectively improved.

A tool and method for screening cryogenic electron microscopy (cryo-EM) sample grids using vacuum ultraviolet (VUV) illumination in two configurations. First configuration directly images cryo-EM grids using bright-field optical microscopy employing VUV wavelengths and specialized VUV optics. Second configuration converts transmitted VUV radiation from the cryo-EM grid to visible or near-UV light with a scintillator positioned by the grid. The resultant luminescent high-resolution shadow image is viewed using more conventional microscope optics. In both configurations, individual micron-scale grid holes are imaged to determine ice thickness and quality from the optical absorption of ultrathin vitrified water layers with a precision of a few nanometers. Longer wavelengths can be used to independently view protein concentration and distribution within the ice layer. This tool greatly increases yield of high-quality grids before cryo-EM analysis and is compatible with Single Particle Analysis (SPA) and other cryo-EM methods including cryo-electron Tomography and microcrystal electron diffraction.

The invention belongs to the field of metal material sample preparation, and particularly relates to an oxide scale powder transmission electron microscope sample preparation method which comprises the following steps: 1) grinding oxide scale stripped from the surface of a sample into a nano-scale powder sample; (2) preparing a mixed solvent from absolute ethyl alcohol and deionized water, pouring the oxide scale powder into the mixed solvent, and uniformly stirring; (3) dropwise adding a surfactant into the mixed solvent, uniformly stirring, putting into an ultrasonic cleaner, and carrying out ultrasonic oscillation; (4) flatly placing a piece of carbon support film carrying net for the transmission electron microscope on filter paper with the front face facing upwards, dripping the mixed solvent onto the carbon support film, and naturally drying in the air; and in a high-vacuum coating instrument, vacuumizing, evaporating a carbon film, and releasing vacuum to finish sample preparation. The method has the advantages that the prepared sample is in a thin-layer, uniform and single-particle dispersed state, and the requirements of high-resolution transmission electron microscope (HRTEM) imaging and selective area electron diffraction (SAED) analysis are completely met.

This invention relates to a method for preparing a positive electrode active material, a positive electrode, and a rechargeable lithium battery. The positive electrode includes a positive electrode active material, which comprises a lithium-nickel-based composite oxide and is in the form of single particles. The volumetric cumulative average particle size (D) of the positive electrode active material is measured using a particle size analyzer. 50 The ratio of the grain size of the positive electrode active material measured by backscattered electron diffraction after ion milling of the positive electrode was 1.6 to 1.8.

The invention discloses an arc ablation copper-tungsten contact material performance evaluation method, and belongs to the field of high-voltage switch equipment material testing. The method comprises the following steps: carrying out an ablation test on a material through a high-power pulse discharge system, and measuring a melting threshold value; mass loss before and after ablation is measured, and the ablation rate is calculated; a white light interferometer is used for collecting the three-dimensional shape of an ablation area, and the average melting depth is calculated; counting the maximum crack width of the surface by using a scanning electron microscope, and obtaining the maximum depth of the crack by observing the cross section; analyzing a microstructure by using back scattering electron diffraction, and counting a large-angle grain boundary proportion; and finally, selecting the six parameters as key indexes, and calculating a comprehensive performance score in combination with weight distribution. According to the method, a multi-dimensional evaluation system covering macroscopic thermal damage, surface topography characteristics and a microstructure is constructed, the limitation of single index evaluation is overcome, and accurate quantitative evaluation of arc ablation resistance and crack resistance of the copper-tungsten contact material is realized.

This invention relates to the field of thin film material preparation technology, specifically to a method for preparing a single-crystal transition metal nitride epitaxial thin film with an anti-perovskite structure. In a molecular beam epitaxy (MBE) apparatus, after heating the single-crystal substrate, a transition metal atom beam and an active nitrogen atom beam generated by a radio frequency plasma source are supplied simultaneously and independently. By precisely controlling the beam ratio, growth is kept within a narrow stoichiometric window. During growth, in-situ real-time monitoring is performed using reflective high-energy electron diffraction to ensure the film grows in a two-dimensional layered manner. Finally, the film is slowly cooled in an active nitrogen atmosphere. This method can prepare single-crystal thin films with atomically flat surfaces, high phase purity, excellent crystallinity, and a clear epitaxial relationship, exhibiting fewer nitrogen vacancy defects and significantly optimized magnetic and other physical properties.

The invention discloses a quartz cause identification method based on scanning electron microscope multi-mode signal fusion, which only uses a scanning electron microscope equipped with an energy spectrum probe, a cathode luminescence probe and a back scattering electron diffraction probe. A plurality of index factors such as a CL girdle width variation coefficient a, an Al-Ti influence coefficient b, a lattice orientation difference influence coefficient c and an inclusion type relative specific gravity coefficient d are comprehensively adopted to judge that the quartz sample is a hydrothermal cause or a metamorphic cause. According to the invention, rapid and accurate identification of quartz causes is realized.

The present application belongs to the field of condensed matter physics and material science technology, and particularly relates to an ultrathin single-crystal ferroelectric PZT film and a preparation method thereof. The present application adopts a pulsed laser deposition (PLD) method, and uses pulsed laser to bombard a PZT target material to grow a single-crystal ferroelectric PZT film on a single-crystal substrate. The deposition process includes two stages: a single-crystal layer growth stage and a rapid cooling stage. The method is simple and easy to operate, and the growth of the ultrathin ferroelectric single-crystal film is realized by controlling the laser energy, the substrate deposition growth temperature and the oxygen pressure during the PLD growth. In the present application, a high-energy electron diffraction (RHEED) instrument is used to monitor the growth process in real time, so as to ensure the crystal quality and thickness of the film during the growth. The atomic force microscope is used to observe the morphology of the prepared sample, and the atomic-level flatness of the surface is verified. The PZT film grown on the single-crystal substrate still maintains the ferroelectricity even when it is only 2 lattice layers thick, and the ferroelectric polarization reversal can be realized.

The invention belongs to the field of microcrystal structure analysis, and particularly relates to a MicroED data acquisition and image correction system and method based on software linkage, and the system comprises a data acquisition module and a background correction and format conversion module which are communicated with each other. The data acquisition module is used for controlling the transmission electron microscope to shoot a microcrystalline electron diffraction image of a sample to be detected and outputting the diffraction image to the background correction and format conversion module; the background correction and format conversion module is used for carrying out dark background and bright background correction on the diffraction image; the data acquisition module comprises an electron microscope control unit and a camera control unit, and the camera control unit is used for controlling a camera to carry out image acquisition on the electron microscope and outputting a standardized data packet. According to the invention, on the premise of camera bottom layer driving, MicroED data automatic acquisition and data batch background correction of the interface-free camera can be realized.

The application provides a liquid-phase crystal structure three-dimensional electron diffraction data acquisition method and device, and belongs to the field of crystal structure analysis. The method provided by the application comprises the following steps: immersing a nanocrystal to be collected in a solvent; adding a first volume of the solvent on the front surface of a first continuous carbon support net; covering a second continuous carbon support net on the first continuous carbon support net, and the edges and front surface of the first continuous carbon support net and the second continuous carbon support net form a sealed double continuous carbon support net liquid pool; loading the double continuous carbon support net liquid pool on a sample rod; positioning the nanocrystal to be collected in the double continuous carbon support net liquid pool by using an electron microscope, rotating the sample rod, and collecting three-dimensional electron diffraction data of the nanocrystal to be collected. The liquid-phase crystal structure three-dimensional electron diffraction data acquisition method and device provided by the application can realize high-quality three-dimensional electron diffraction data acquisition of nanocrystals in a liquid-phase environment.

Systems and methods are provided for controlled growth of nanocrystals suitable for electron diffraction measurements for atomic structure assays. The fluid support structure is contacted with a solution containing a nanocrystal-forming material such that the solution remains on the fluid support structure. An energy beam configured to locally induce nucleation and nanocrystal growth is delivered to spatially separated locations on the fluid support structure, thereby forming spatially separated nanocrystals. The fluid support structure is capable of retaining a solution having a sufficiently thin layer such that the nanocrystal has a submicron thickness suitable for analysis by electron diffraction without the need to transfer the nanocrystal to a separate gripper. The fluid support structure may include a lateral fluid confinement structure defining a plurality of nanocrystal growth regions such that each nanocrystal growth region is confined laterally over a submicron to micron scale to isolate the grown nanocrystals, thereby creating conditions for uniform nanocrystal growth.

A method and a dual beam FIB / (S)TEM apparatus are provided for in-situ sample quality inspection in cryogenic focused ion beam milling. The method comprises the steps of: loading the sample into a sample holder of the dual beam FIB / (S)TEM apparatus, wherein the (S)TEM apparatus comprises an electron column and a detector, wherein the sample holder is arranged in between the electron column and the detector; obtaining an image of the electrons that have passed through the sample using the electron column to direct an electron beam towards the sample and using the detector to detect electrons passing through the sample; and using a scattering pattern in the image of the transmitted electrons to establish a measure for the thickness of the sample and to establish whether or not the image comprises a diffraction signal due to electron diffraction from ice crystals.

The invention provides a liquid crystal structure three-dimensional electron diffraction data acquisition method and device, and belongs to the field of crystal structure analysis. The method provided by the invention comprises the following steps: soaking a nanocrystal to be collected in a solvent; dropwise adding a first volume of the solvent on the front surface of the first continuous carbon grid; a second continuous carbon carrying net directly covers the first continuous carbon carrying net, and the edges and the front faces of the first continuous carbon carrying net and the second continuous carbon carrying net enclose a sealed bicontinuous carbon carrying net liquid pool; loading the bicontinuous carbon carrying net liquid pool on a sample rod; and positioning the nanocrystals to be collected in the bicontinuous carbon grid liquid pool by using an electron microscope, controlling the sample rod to rotate, and collecting three-dimensional electron diffraction data of the nanocrystals to be collected. According to the liquid phase crystal structure three-dimensional electron diffraction data acquisition method and device provided by the invention, high-quality three-dimensional electron diffraction data acquisition can be carried out on nanocrystals in a liquid phase environment.