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In chemistry, a formula unit is the smallest unit of a non-molecular substance, such as an ionic compound, covalent network solid, or metal. [ 1 ] [ 2 ] It can also refer to the chemical formula for that unit.
3-dimensional [18 F]FDG-PET image with 3D ROI generated by a threshold based algorithm.The blue dot in the MIP image bottom right marks the maximum SUV within the ROI.. The standardized uptake value (SUV) is a nuclear medicine term, used in positron emission tomography (PET) as well as in modern calibrated single photon emission tomography (SPECT) imaging for a semiquantitative analysis. [1]
A computer-generated image of an Airy disk. ... is given by the approximate formula: ... is the source strength per unit area at the aperture, ...
The magnitude of an object's solid angle in steradians is equal to the area of the segment of a unit sphere, centered at the apex, that the object covers. Giving the area of a segment of a unit sphere in steradians is analogous to giving the length of an arc of a unit circle in radians. Just as the magnitude of a plane angle in radians at the ...
The prime example is yttrium barium copper oxide (YBCO), which has the formula YBa 2 Cu 3 O 7. In this material Y 3+ and Ba 2+, which are relatively large, occupy all A sites. Cu occupies all B sites. Two O atoms per formula unit are absent, hence the term defect. The compound YBa 2 Cu 3 O 7 is a superconductor.
The ability of a lens to resolve detail is usually determined by the quality of the lens, but is ultimately limited by diffraction.Light coming from a point source in the object diffracts through the lens aperture such that it forms a diffraction pattern in the image, which has a central spot and surrounding bright rings, separated by dark nulls; this pattern is known as an Airy pattern, and ...
In order to evaluate the image quality, this formula is usually applied only on luma, although it may also be applied on color (e.g., RGB) values or chromatic (e.g. YCbCr) values. The resultant SSIM index is a decimal value between -1 and 1, where 1 indicates perfect similarity, 0 indicates no similarity, and -1 indicates perfect anti-correlation.
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 how close lines can be to each other and still be visibly resolved. Resolution units can be tied to ...