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Transmission Kikuchi Diffraction
Transmission Kikuchi Diffraction (TKD), also sometimes called transmission electron backscatter diffraction (t-EBSD), is a method for orientation mapping at the nanoscale. It’s used for analysing the microstructures of thin transmission electron microscopy (TEM) specimens in the scanning electron microscope (SEM). This technique has been widely utilised in the characterization of nano-crystalline materials, including oxides, superconductors, and metallic alloys. TKD offers improved spatial resolution, enabling effective characterization of nanocrystalline materials and heavily deformed samples where high dislocation densities can prevent successful characterization using conventional Electron backscatter diffraction. Many studies have reported sub-10 nm resolution using TKD. The main difference between diffraction spots and Kikuchi bands is that in TEM, discrete diffraction spots arise from coherent scattering of the incident beam, while the formation of Kikuchi bands is describe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Backscatter Diffraction
Electron backscatter diffraction (EBSD) is a scanning electron microscopy (SEM) technique used to study the Crystallography, crystallographic structure of materials. EBSD is carried out in a scanning electron microscope equipped with an EBSD detector comprising at least a Phosphorescence, phosphorescent screen, a compact lens and a low-light Charge-coupled device, camera. In the microscope an incident beam of electrons hits a tilted sample. As backscattered electrons leave the sample, they interact with the atoms and are both elastically Electron diffraction, diffracted and lose energy, leaving the sample at various scattering angles before reaching the phosphor screen forming Kikuchi lines (physics), Kikuchi patterns (EBSPs). The EBSD spatial resolution depends on many factors, including the nature of the material under study and the sample preparation. They can be indexed to provide information about the material's grain Crystal structure, structure, grain Electron crystallogr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Microscopy
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction
Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation, propagating wave. Diffraction is the same physical effect as Wave interference, interference, but interference is typically applied to superposition of a few waves and the term diffraction is used when many waves are superposed. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660 in science, 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic pattern is most pronounced when a wave from a Coherence (physics), coherent source (such as a laser) encounters a slit/aperture tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TKD Map
Taekwondo (; ; ) is a Korean martial art and combat sport involving primarily kicking techniques and punching. "Taekwondo" can be translated as ''tae'' ("strike with foot"), ''kwon'' ("strike with hand"), and ''do'' ("the art or way"). In addition to its five tenets of courtesy, integrity, perseverance, self-control and indomitable spirit, the sport requires three physical skills: ''poomsae'' (, Form), ''kyorugi'' (, Sparring) and ''gyeokpa'' (, Breaking Technique). Poomsae are patterns that demonstrate a range of kicking, punching and blocking techniques, kyorugi involves the kind of sparring seen in the Olympics, and gyeokpa is the art of breaking wooden boards. Taekwondo also sometimes involves the use of weapons such as swords and nunchucks (nunchaku). Taekwondo practitioners wear a uniform known as a . Taekwondo is a combat sport which was developed during the 1940s and 1950s by Korean martial artists with experience in martial arts such as karate and Chinese martial ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Milling Machine
Ion milling is a specialized physical etching technique that is a crucial step in the preparation of material analysis techniques. After a specimen goes through ion milling, the surface becomes much smoother and more defined, which allows scientists to study the material much easier. The ion mill generates high-energy particles to remove material off the surface of a specimen, similar to how sand and dust particles wear away at rocks in a canyon to create a smooth surface. Relative to other techniques, ion milling creates much less surface damage,B. Chapman, A. R. Inamdar, and D. C. Joy. (1999). "Preparation of transmission electron microscopy samples of composite materials". ''Materials Characterization'', 43(1), 53–59. which makes it perfect for surface-sensitive analytical techniques. This article discusses the principle, equipment, applications, and significance of ion milling. Principles Ion milling operates on the principles of sputtering and erosion. Sputtering occurs as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focused Ion Beam
Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor industry, materials science and increasingly in the biological field for site-specific analysis, deposition, and ablation of materials. A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, a FIB setup uses a focused beam of ions instead. FIB can also be incorporated in a system with both electron and ion beam columns, allowing the same feature to be investigated using either of the beams. FIB should not be confused with using a beam of focused ions for direct write lithography (such as in proton beam writing). These are generally quite different systems where the material is modified by other mechanisms. Ion beam source Most widespread instruments are using liquid metal ion sources (LMIS), especially gallium ion sources. Ion sources based on elemental gold an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Transmission Electron Microscopy
A scanning transmission electron microscope (STEM) is a type of transmission electron microscope (TEM). Pronunciation is [stɛm] or [ɛsti:i:ɛm]. As with a conventional transmission electron microscope (CTEM), images are formed by electrons passing through a sufficiently thin specimen. However, unlike CTEM, in STEM the electron beam is focused to a fine spot (with the typical spot size 0.05 – 0.2 nm) which is then scanned over the sample in a raster illumination system constructed so that the sample is illuminated at each point with the beam parallel to the optical axis. The rastering of the beam across the sample makes STEM suitable for analytical techniques such as Z-contrast annular dark-field imaging, and spectroscopic mapping by energy-dispersive X-ray spectroscopy, energy dispersive X-ray (EDX) spectroscopy, or electron energy loss spectroscopy (EELS). These signals can be obtained simultaneously, allowing direct correlation of images and spectroscopic data. A ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark-field Microscopy
Dark-field microscopy, also called dark-ground microscopy, describes microscopy methods, in both light and electron microscopy, which exclude the unscattered beam from the image. Consequently, the field around the specimen (i.e., where there is no specimen to scatter the beam) is generally dark. In optical microscopes a darkfield condenser lens must be used, which directs a cone of light away from the objective lens. To maximize the scattered light-gathering power of the objective lens, oil immersion is used and the numerical aperture (NA) of the objective lens must be less than 1.0. Objective lenses with a higher NA can be used but only if they have an adjustable diaphragm, which reduces the NA. Often these objective lenses have a NA that is variable from 0.7 to 1.25. Light microscopy applications In optical microscopy, dark-field describes an illumination technique used to enhance the contrast in unstained samples. It works by illuminating the sample with light that wil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatial Resolution
In physics and geosciences, the term spatial resolution refers to distance between independent measurements, or the physical dimension that represents a pixel of the image. While in some instruments, like cameras and telescopes, spatial resolution is directly connected to angular resolution, other instruments, like synthetic aperture radar or a network of weather stations, produce data whose spatial sampling layout is more related to the Earth's surface, such as in remote sensing and satellite imagery. See also * Image resolution Image resolution is the level of detail of an image. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies ... * Ground sample distance * Level of detail * Resel References Accuracy and precision {{physics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent-beam Electron Diffraction
Convergent beam electron diffraction (CBED) is an electron diffraction technique where a convergent or divergent beam (conical electron beam) of electrons is used to study materials. History CBED was first introduced in 1939 by Kossel and Möllenstedt. The development of the Field Emission Gun (FEG) in the 1970s, the Scanning Transmission Electron Microscopy (STEM), energy filtering devices and so on, made possible smaller probe diameters and larger convergence angles, and all this made CBED more popular. In the seventies, CBED was being used for the determination of the point group and space group symmetries by Goodman and Lehmpfuh, and Buxton, and starting in 1985, CBED was used by Tanaka et al. for studying crystals structure. Applications By using CBED, the following information can be obtained: *parameters of the crystal lattice, sample thickness *strain distribution * defects such as stacking faults, dislocations, grain boundaries, three-dimensional deformations, lattice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Electron Microscopy
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device, such as a fluorescent screen, a layer of photographic film, or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope. Transmission electron micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microstructure
Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material (such as metals, polymers, ceramics or composites) can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice. Microstructure at scales smaller than can be viewed with optical microscopes is often called nanostructure, while the structure in which individual atoms are arranged is known as crystal structure. The nanostructure of biological specimens is referred to as ultrastructure. A microstructure's influence on the mechanical and physical properties of a material is primarily governed by the different defects present or absent of the structure. These defects can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
