54 results about "Electron diffraction pattern" patented technology

A method and device for electron diffraction tomography of a crystal sample, which employs scanning of the electron beam over a plurality of discrete locations of the sample, in combination with a beam scanning protocol as the beam converges at every discrete location (42, 43) of the sample (38) to obtain a series of electron diffraction patterns, use of template matching to determine crystal orientations and thickness maps to obtain a common intensity scaling factor.

A device and method which enable a transmission electron microscope to measure electron diffraction patterns of a sample very precisely are disclosed. The patterns are suitable for structure determination. The electron beam is precessed by means of deflector coils (6) in the transmission electron microscope before the sample (4), in combination with a similar precession of the electron diffraction pattern by means of deflector coils (9) situated after the sample. The electron diffraction pattern is scanned by means of deflector coils (9) situated after the sample.

An aberration-correcting microscopy instrument is provided. The instrument has a first magnetic deflector disposed for reception of a first non-dispersed electron diffraction pattern. The first magnetic deflector is also configured for projection of a first energy dispersed electron diffraction pattern in an exit plane of the first magnetic deflector. The instrument also has an electrostatic lens disposed in the exit plane of a first magnetic deflector, as well as a second magnetic deflector substantially identical to the first magnetic deflector. The second magnetic deflector is disposed for reception of the first energy dispersed electron diffraction pattern from the electrostatic lens. The second magnetic deflector is also configured for projection of a second non-dispersed electron diffraction pattern in a first exit plane of the second magnetic deflector. The instrument also has an electron mirror configured for correction of one or more aberrations in the second non-dispersed electron diffraction pattern. The electron mirror is disposed for reflection of the second non-dispersed electron diffraction pattern to the second magnetic deflector for projection of a second energy dispersed electron diffraction pattern in a second exit plane of the second magnetic deflector.

Provided are carbide derived carbon prepared by thermochemically reacting carbide compounds and a halogen element containing gas and extracting all atoms of the carbide compounds except carbon atoms, wherein the intensity ratios of the graphite G band at 1590 cm−1 to the disordered-induced D band at 1350 cm−1 are in the range of 0.3 through 5 when the carbide derived carbon is analyzed using Raman peak analysis, wherein the BET surface area of the carbide derived carbon is 1000 m2/g or more, wherein a weak peak or wide single peak of the graphite (002) surface is seen at 2θ=25° when the carbide derived carbon is analyzed using X-ray diffractometry, and wherein the electron diffraction pattern of the carbide derived carbon is the halo pattern typical of amorphous carbon when the carbide derived carbon is analyzed using electron microscopy. The emitter has good uniformity and a long lifetime. An emitter can be prepared using a more inexpensive method than that used to manufacture conventional carbon nanotubes.

The invention provides an electrochemical method for preparing a regularly ordered Ni tubular nano array with an AAO (Anodic Aluminum Oxide) template in an ammonium sulfate system. With the method, a Ni nano tube, of which the external diameter is about 70nm and the inner diameter is about 50nm, can be obtained. The obtained Ni nano tube can be represented by a scanning electron microscope (SEM), a transmission electron microscope (TEM), a selected area electron diffraction (SAED) pattern and an X-ray diffraction (XRD). The Ni nano tube prepared by the method is ordered in height and uniform in size, the appearance of the Ni nano tube is dependent on the structure of the AAO template, and the external diameter of the Ni nano tube is equal to the pore diameter of the template.

An energy filtering microscopy instrument is provided. An objective lens is disposed for reception of electrons in order to form an electron diffraction pattern in a backfocal plane of the objective lens. An entrance aperture disposed in the backfocal plane of the objective lens for filtering a slice of the electron diffraction pattern. A magnetic deflector has an entrance plane and an exit plane. The entrance aperture is disposed in the entrance plane. The magnetic deflector is disposed to receive the slice of the electron diffraction pattern and project an energy dispersed electron diffraction pattern to the exit plane. An exit aperture is disposed in the exit plane of the magnetic deflector for selection of desired electron energy of the energy dispersed electron diffraction pattern.

Provided are carbide derived carbon materials prepared by thermochemically reacting carbide compounds and a halogen containing gas and extracting all atoms of the carbide compounds except carbon atoms, wherein the intensity ratios of the graphite G band at 1590 cm -1 to the disordered-induced D band at 1350 cm-1 are in the range of 0.3 through 5 when the carbide derived carbon is analyzed using Raman peak analysis, wherein the BET surface area of the carbide derived carbon is 1000 m 2 /g or more, wherein a weak peak or wide single peak of the graphite (002) surface is seen at 2 = 25 DEG when the carbide derived carbon is analyzed using X-ray diffractometry, and wherein the electron diffraction pattern of the carbide derived carbon is the halo pattern typical of amorphous carbon when the carbide derived carbon is analyzed using electron microscopy.

The invention discloses a method for rapidly and accurately measuring low angle grain boundary orientation under a transmission electron microscope. The method comprises the following steps: using a transmission electron microscope double bar-tilting rotation tilting sample, enabling a zone axis of a crystalline grain I in a coordinate system I to be at the position of a positive zone axis, and collecting a convergent beam electron diffraction pattern of the crystalline grain I at the moment; keeping a camera constant L of the transmission electron microscope and the parameter of the convergent beam diffraction condition unchanged, and collecting a convergent beam electron diffraction pattern of a crystalline grain II in a coordinate system II; superposing a kikuchi pattern of the collected crystalline grain I and a kikuchi pattern of the collected crystalline grain II by using software; measuring the distance S between a kikuchi pole of the crystalline grain I and a kikuchi pole of the crystalline grain II as well as the rotation angle gama of the kikuchi pole of the crystalline grain II vertical to the pattern surface relatively to the kikuchi pole of the crystalline grain I; calculating the angle theta according to the geometric characteristic of the kikuchi line, theta=arctan(s/L)=s/L; using a formula (6) cos theta=(cosgama+cosgamacostheta+costheta-1)/2 to calculate the orientation of the crystalline grain I and the crystalline grain II. The method does not need the additional installation of hardware and software, and the common transmission electron microscope is used to measure the orientation.

The invention relates to a method for nano-crystallization of a Zr-based amorphous alloy induced by nanoindentation combined with fatigue load, and belongs to the field of amorphous alloy modification. An original test piece with double V-notch is subjected to XRD test, the test piece is subjected to a tensile experiment by using a high-temperature fatigue tester, pre-tensile loadsare applied to both ends of the test piece, meanwhile fatigue loads are applied through piezoelectric stack on one side of the test piece until the test piece is broken,and the XRD pattern of the test piece after breakage shows a steamed break-like diffuse peak and indicates thatthe test piece after fatigue break does not crystallize; a indentation test is carried out on the test piece after the fatigue break, and the indentation with the most serious plastic accumulation is selected from an indentation topography and subjected to FIB cutting to obtain a TEM sample. The crystallization phenomena at differentdistances from the inclined surface of the indentation are observed by an electron diffraction pattern, and the precipitation of nanocrystals in the amorphous alloy is observed by TEM bright/dark field imaging;and the steps are repeated in the test piece after tensile failureto observea TEM dark field image.

The invention discloses an electrolytic polishing solution of an invar alloy and an electrolytic polishing method. The electrolytic polishing solution of the invar alloy is characterized in that C3H8O2, HClO4 and C2H5OH are mixed according to the volume ratio of 1 to 2 to 17-22; the invar alloy sample is placed in the electrolytic polishing solution as an anode, and insoluble metal is used as a cathode; and the temperature of the electrolytic polishing solution is 0-10 DEG C, the polishing voltage is 30-40 V, and electrolytic polishing is carried out on an invar alloy sample. According to themethod, the polishing solution is simple to prepare and good in polishing effect, the surface of the sample is flat and smooth, no obvious deformation layer is generated, and the polishing solution can be used multiple times; the stress layer on the surface can be effectively removed, the electrolytic polishing quality is effectively improved, and the high-calibration rate electron diffraction pattern is obtained; the electrolytic polishing method can effectively remove the stress layer on the surface of the sample, the electrolytic polishing quality is effectively improved, and the strong diffraction pattern which is generated by the EBSD test is facilitated, so that the high-calibration rate can be obtained, and the research of microstructure of the crystal boundary characteristic, texture, stress strain and the like of the invar alloy is facilitated.

An electron microscope includes: an irradiation lens system that irradiates a specimen with an electron beam; an irradiation system deflector that deflects an electron beam incident on the specimen; a specimen tilting mechanism that tilts the specimen; an imaging lens system that forms an electron diffraction pattern or an electron microscope image by using an electron having passed through the specimen; an imaging device that acquires the electron diffraction pattern or the electron microscope image formed by the imaging lens system; and a controller that controls the irradiation system deflector and the specimen tilting mechanism. The controller performs: a process of acquiring a plurality of electron diffraction patters formed by using electron beams having different incidence angles to the specimen, the different incidence angles having been obtained by deflecting the electron beams incident on the specimen by using the irradiation system deflector; a process of calculating a tilt angle of the specimen based on the plurality of electron diffraction patterns; and a process of controlling the specimen tilting mechanism so that the specimen has the calculated tilt angle.

The invention relates to a preparation method for an as-cast lead or lead alloy EBSD (electron back-scattered diffraction) sample. The method includes: manual polishing: using waterproof abrasive paper to polish a to-be-tested surface of the as-cast lead or lead alloy sample; chemical polishing 1: adding a chemical polishing solution composed of H2O2 and CH3COOH in a volume ratio of 0.8-1.2:0.8-1.2 to the to-be-tested surface dropwise; chemical polishing 2: then adding a chemical polishing solution composed of H2O2 and CH3COOH in a volume ratio of 0.05-0.2:0.8-0.95 to the to-be-tested surface dropwise; erosion: covering the sample surface by an erosion solution composed of citric acid, ammonium molybdate and deionized water in a weight ratio of 10-20:6-12:60-150, then soaking the sample in alcohol for 5-10 seconds, then taking the sample out and blowing it dry, thus obtaining the sample that can display Kikuchi lines through the electron back-scattered diffraction technology. The sample preparation method is simple in operation, and the prepared sample has real texture and a high back-scattered electron diffraction pattern calibration rate.

The system comprises: a HEEP fluorescent screen, a CCD cam behind the screen fixed by a stainless cylinder, an image acquisition card connected with the cam by a video line to convert the obtained analog signal into the digital signal and store in memory, and a computer with data to image the data on screen.

Provided is a transmission electron diffraction measurement apparatus including an electron gun; a first optical system under the electron gun; a sample chamber under the first optical system; a second optical system under the sample chamber; an observation chamber under the second optical system; a region that emits light by receiving energy from an electron in the observation chamber; and a camera facing the region.

The invention discloses a selected area electron diffraction pattern and image processing method for determining preferred orientation degree of pyrolytic carbon. The method comprises the following steps that binarization processing is performed on an original pattern, a diffraction ring and an inner area of the diffraction ring, a brightness value of which is greater than or equal to 50, is selected, and marginalized processing is performed; bright area boundaries are determined, a least square method is used for fitting a center of a circle and a radius, and an approximate center of the circle and an approximate radius of the diffraction ring are obtained; according to the approximate center of the circle and the approximate radius, a small radius of a circular area is 0.7 times the approximate radius, and a large radius of the circular area is 1.2 times the approximate radius; an inner area and an outer area of the diffraction ring are deducted, then the binarization processing is performed again, a part, the brightness value of which is greater than or equal to 145, is selected from the circular area, i.e. the diffraction ring; and according to the least square method, the center of the circle and the radius of the diffraction ring are fitted again, pattern sampling points are determined, and a strength-azimuth curve is obtained to determine the preferred orientation degree of the pyrolytic carbon. By using the method, the strength-azimuth curve of a pyrolytic carbon coating can be simply, conveniently and accurately obtained, so as to determine the preferred orientation degree of the pyrolytic carbon.

A method and system for processing a diffraction pattern image obtained in an electron microscope are disclosed. The method comprises, according to a first set of microscope conditions, causing an electron beam to impinge upon a calibration specimen so as to cause resulting electrons to be emitted therefrom and monitoring the resulting electrons using a detector device so as to obtain a calibration image comprising a plurality of pixels having values, the first set of microscope conditions being configured such that the calibration image includes substantially no electron diffraction pattern; obtaining, from the calibration image, a gain variation image comprising a plurality of pixels, each having a value representing relative detector device gain for a corresponding pixel of the calibration image; according to a second set of microscope conditions, causing an electron beam to impinge upon a target specimen so as to cause resulting electrons to be emitted therefrom and monitoring the resulting electrons using the detector device so as to obtain a target image comprising a plurality of pixels having values, the second set of microscope conditions being configured such that the target image includes an electron diffraction pattern; and for each pixel of the target image, removing from the pixel value, in accordance with the value of the corresponding pixel of the gain variation image, the contribution to the pixel value of the relative detector device gain, so as to obtain a gain variation-corrected image.

The invention provides a femtosecond electronic diffraction device based on laser plasma wake-field acceleration, comprising a laser, a gas generator, a micropore, a magnetic lens, a sample rack, a detection system, a vacuum chamber, a vacuum system, a five-dimensional system and the like, wherein the laser is used for generating ultrashort ultra-high laser pulses, the gas generator is used for generating a high-density gas target, the ultrashort ultra-high laser pulses may react with the gas target to generate electron beams, and the electron beams are collimated by the micropore and condensed by the magnetic lens and then act with a sample to generate an electronic diffraction pattern that is collected by the detection system. The device of the invention is up to 10 femtoseconds in time resolution, pumped light and detection electron beams are in good time synchronization in a femtosecond electronic diffraction experiment, there is no need for a photoelectric cathode, a high-pressure electrode or microwave source and other components, and therefore the device is simpler and more compact and is widely applicable to the scientific research of ultrafast dynamic process.

The invention belongs to the technical field of material microstructure analysis and crystal structure characterization, and particularly relates to a method for reconstructing a crystal Bravais lattice by using an electron diffraction pattern. The method can be used for phase recognition of materials and reconstruction of Brafir of known or unknown phases, and is particularly suitable for occasions where three diffraction patterns are difficult to obtain, a belt axis is strictly tilted, and the tilt angle is accurately determined. For example the following occasion, when the crystal grain is small, the crystallinity is poor, and the crystal surface is uneven, the crystal belt shaft is difficult to strictly tilt, and the tilt angle error is large.

The invention relates to a method for carrying out object phase identification by utilizing two electron diffraction patterns with axes or high-resolution images, and belongs to the technical field of material microstructure analysis and crystal structure characterization. According to the method, a high-symmetry belt axis does not need to be tilted, a strict positive belt axis does not need to be tilted, tilting information of each electron diffraction piece does not need to be recorded, and a transmission electron microscope does not need to be provided with an objective lens with a large pole shoe; according to the method, a reciprocal space reconstruction method and a traditional indexing method are combined, and through double inspection of primary group primitive cells and a reciprocal angle alpha*, the uncertainty of the traditional indexing method can be effectively overcome, and the crystal phase can be accurately identified. In an actual electron microscope experiment, the crystal tilting can be greatly simplified, and the provided analysis method is not influenced by a crystal system and the symmetry, and is suitable for phase identification of all crystal systems.