why xrd peaks how broadening?
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According to the theory of kinematical scattering, X-ray diffraction peaks broaden either when crystallites become smaller than about a micrometer or if lattice defects are present in large enough abundance. In terms of dislocations this means a dislocation density larger than about 5 × 1012 m−2.
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X-rays are produced due to sudden deceleration of fast-moving electrons when they collide and interact with the target anode. In this process of deceleration, more than 99% of the electron energy is converted into heat and less than 1% of energy is converted into x-rays.
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From top to bottom of the periodic table ions will increase in radii. However, now left to right the radius is more of a function of the number of electrons. Mg2+ is smaller than Na+. Both have 10 electrons but Z=12 for Mg and Z=11 for Na.
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X-ray production. ... X-rays are produced due to sudden deceleration of fast-moving electrons when they collide and interact with the target anode. In this process of deceleration, more than 99% of the electron energy is converted into heat and less than 1% of energy is converted into x-rays.
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Particularly in larger body parts, such as obese adult torsos, lower energy photons are absorbed completely without contributing to image formation. In such situations, higher kVp is employed to improve the x-ray intensity reaching the receptor, thus increasing the signal to noise ratio on the images.
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The normal range of vitamin D is measured as nanograms per milliliter (ng/mL). Many experts recommend a level between 20 and 40 ng/mL. Others recommend a level between 30 and 50 ng/mL. The examples above are common measurements for results of these tests.
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As the acid or the base being titrated becomes weaker (its pKa or pKb becomes larger), the pH change around the equivalence point decreases significantly. With very dilute solutions, the curve becomes so shallow that it can no longer be used to determine the equivalence point.
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If the lattice energy (cost) is larger than the energy of solvation of the ions (gain) the compound won't dissociate, and it will be insoluble. There is a large grey area where lattice energy and solvation energy are close, and for those compounds temperature has a big influence on solubility.
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X-rays are used for studying crystals structure of solids.
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In the mass spectrum, the heaviest ion (the one with the greatest m/z value) is likely to be the molecular ion. Base peak: The most intense (tallest) peak in a mass spectrum, due to the ion with the greatest relative abundance (relative intensity; height of peak along the spectrum's y-axis).
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XRF is a non-destructive analytical technique that measures the fluorescent (or secondary) x-ray emitted from a sample when it is excited by a primary x-ray source. The strength of the signal can be used to determine the thickness of the coating; a second reading can determine the thickness of the substrate.
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Our model shows that as grain size increases, the weathering rate initially decreases; however, beyond a critical size no significant decrease in the rate is observed. This transition occurs when the density of reactive boundaries is less than ∼ 20 % of the entire domain.
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Scintillators work by converting X-ray energy into visible light. The energy of the incoming X-ray is completely absorbed by the material, exciting a molecule of the detector material. When the molecule de-excites, it emits a pulse of light, this time in the optical region of the electromagnetic spectrum.
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Equation (1) indicates that the resolution is the difference between peak retention times divided by the average peak width. In a peak with Gaussian distribution, the peak width is W = 4 σ (where σ is the standard deviation) and the peak FWHM is W0. 5h = 2.354σ.
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XRF (x-ray fluorescence) works by exciting the electrons in atoms, causing a change in energy, which is then detected by the instrument's detector. ... A high-energy primary x-ray beam is emitted from the x-ray tube of an XRF analyzer.
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X-rays are used to produce the diffraction pattern because their wavelength λ is typically the same order of magnitude (1–100 angstroms) as the spacing d between planes in the crystal. ... However, visible light has too long a wavelength (typically, 5500 angstroms) to observe diffraction from crystals.
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XRD analysis, by way of the study of the crystal structure, is used to identify the crystalline phases present in a material and thereby reveal chemical composition information. ... X-ray diffraction is useful for evaluating minerals, polymers, corrosion products, and unknown materials.