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Characterization Techniques of Nanoparticles Applied in Drug Delivery Systems
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Vipin Kumar Sharma, Daphisha Marbaniang
XRD are electromagnetic radiations that are similar to light but with a much shorter wavelength (a few Angstrom). They are produced when electrically-charged particles of sufficient energy are decelerated. In an X-ray tube, the high voltage maintained across the electrodes draws electrons toward a metal target (the anode). X-rays are produced at the point of impact and radiate in all directions.
X-Ray Methods
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
The four main components of an X-ray tube (cf. Figure 8.4) are the cathode, which generates electrons; the anode target, which generates X-rays when impacted by the electrons; a vacuum system for maintaining very low pressure in the tube generator; and a beryllium exit window, which is essentially transparent to X-rays. The radiation produced by the tube can be analyzed in a number of ways and will be discussed in the later sections of this chapter.
X-Ray Diffraction
Published in Rui Yang, Analytical Methods for Polymer Characterization, 2018
X-rays are generated when electrons are rapidly decelerated. In an x-ray tube, the electrons from the cathode C are accelerated by the high voltage U and strike the anode A, or the target, with very high speed. X-rays are generated at the point of impact and radiate in all directions, as shown in Figure 8.5.
Recent advances in micro-level experimental investigation in food drying technology
Published in Drying Technology, 2020
Md Imran H. Khan, M. M. Rahman, M. A. Karim
X-ray tomography is a noninvasive technique that allows the visualization of the interior of a specimen via the generation of cross-sectional data.[44] Classical X-ray tomography is based on the attenuation of an X-ray beam by matter (coupled effect of photon energy, atomic number, and linear density). An X-ray attenuation system basically consists of a source and a detector (Figure 2). In conventional X-ray tubes, an electron beam, accelerated by a high voltage, collide with a metal target (anode), producing X-ray photons. In synchrotron facilities, the X-ray beam is produced by the deviation of a high-energy electron beam by intense magnetic fields perpendicular to the beam direction. Synchrotron X-ray beams have high brilliance, a high level of polarization, and small angular divergence. The Synchrotron X-ray detectors are able to form 2-D attenuation images of an object, directly or by scanning over one or two spatial dimensions. The 3 D description of the object is obtained by computed tomography (CT). A suitable algorithm (i.e., filtered back projection) is used to compute in 3-D (voxels) the radiodensity values, also called the CT-numbers, from several 2-D projections, grabbed at different rotation angles of the sample (materials science) or of the tube detector set (medical application and materials science). CT scanning was invented independently in the 1970s by Hounsfield and Cormack, who shared the Nobel Prize for medicine in 1979. Although the first application of computed tomography was primarily in medicine, it rapidly became a very useful tool in physics, materials science and engineering. The initial device has undergone substantial improvement from both technical and computational points of view.