Patterning subtractive

In order to identify caffeine, the XRD patterns of acetaminophen and aspirin were selectively subtracted from the XRD pattern of the formulation. The details of the pattern subtraction procedure are described in... 

For lung heat patterns, subtract Cinnamon and add Gypsum (Shi Gao). This results in Ma Xing Gan Shi Tang (Ephedra, Armeniaca, Licorice, Gypsum Decoction). 

Additive Patterning Subtractive Patterning Other Novel... 

Figure 17.2 is an example of a mass spectrum of an aromatic dichloro compound. The intensity of the molecular ion indicates that an aromatic compound is present. The isotope pattern is that of two chlorines, and subtracting 70 mass units from the molecular ion gives the formula QHj. (See Example 2.3 in Chapter 2 for another example of isotope abundances in the molecular ion region.)... 

In addition to the measured values and the analytical values (e.g. content, concentration), latent variables are included in the scheme. Latent variables can be obtained from measured values or from analytical values by means of mathematical operations (e.g. addition, subtraction, eigenanal-ysis). By means of latent variables and their typical pattern (represented in chemometric displays) special information can be obtained, e.g. on quality, genuineness, authenticity, homogeneity, origin of products, and health of patients. 

If the elliptical parameterization shall be used for automatic alignment of scattering patterns, control of ellipse rotation and displacement are important. Rotation is controlled by subtraction of a constant from v. A displaced center is readily considered by subtraction on the left side of Eqs. (10.6) and (10.7). 

Wang XB et al. Subtracted differential display genes with amphetamine-altered expression patterns include calcineurin. Mol Brain Res 1998 53 344-347. 

An ultrapure polymer is made of chains of the type G1-AAAAAAA-G2, where A is the repeat unit and G1 and G2 are end-groups. One considers the mass number of one of the MS peaks, subtracts the mass of the cation (e.g., H, Li, Na, Ag), and then repeatedly subtracts the mass of the repeat unit, until one obtains the sum of the masses of G1 + G2. For this purpose, a linear best fit can also be used. Tandem mass spectrometry is particularly useful since, from the analysis of ion fragmentation patterns, one can deduce the mass of G1 and, separately, the mass of G2. 

Computer software packages assist in matching the unknown diffraction patterns with a stored database. Problems arise if the sample contains more than one mineral species, since the pattern for each species gives rise to a complex overlapping pattern that cannot be easily interpreted. If one species can be easily identihed and its reflections subtracted from the pattern, it may then be possible to identify a second species. Three species becomes even more complicated. In such circumstances it is advisable if possible to physically sort ( pick ) the sample into different minerals under the microscope before... 

Figure 6. Background estimation of a texture pattern (a) before and (b) after background subtraction.

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