Impurity distribution curves

Any deviation from the living mechanism broadens the distribution. Transfers and termination caused by residual impurities and insufficient mixing are the main causes of improvable broadening of distribution curves. Internal reasons are inherent to two factors, namely to reversibility of propagation and to propagation on centres with various reactivity. 

This order is valid only for the fluorides. It is contingent on the assumption that the observed distribution curves reflect a homogeneous distribution of the impurity ions in the ice lattice without formation of channel networks or interstitial zones of high solute content. 

Spectral, chromatographic, and chemical analysis methods have been used to reduce the duration of the experiment. Extrapolation of the distribution curves of plasticizer concentration is used to calculate the change in plasticizer concentration at the contact boundary and (if the diffusion coefficient is known) to calculate a distribution coefficient. However, these methods are difficult and labor-consuming because extraction of plasticizer from sections of polymer samples is needed. The resulting extract contains a plasticizer, a polymer, and impurities and this complicates analysis. It is frequently necessary to use a special procedure for each plasticizer and calibration curve. The interference method is useful with transparent samples having sufficient difference between the refractive indices of the components (polymer and plasticizer). All methods require perfect contact between the materials being investigated. 

In this equation a, b and e are constants depending on the physical properties of the material to be separated. In Figure 2 the effective distribution coefficient is plotted over the growth rate on the example of a binary mixture of dodecanole with 3,3% impurity of decanole. One curve represents the measured purities (l ff real) is compared to the curve of k ff for the ideal growth rate and... 

Pore volume distributions for the adsorbents into cycle 1 of Figure 7 are shown in Figure 10, Curves 1 and 2. If the bone char had merely lost pore volume and area as a consequence of retained impurities partially... 

A gradual drift in the ratios as shown in Figure 3 definitely indicates impurity. Figure 3 is a distribution with a sample of benzyl-penicillin which contains a few per cent of Zl -pentenylpenicillin. Experimental achievement of the curve of error indicates purity as far as the... 

Another key variable in batch cooling is seeding. The difficulty is in determining the seed point, which is ideally when the batch temperature first crosses the saturation curve. However, this temperature can be affected by batch-to-batch variations in several factors, including the actual concentration of the material to be crystallized, as well as by impurities that can affect the solubility. If the seed is added at a temperature above the solubility temperature, some or all of it can dissolve, resulting in uncontrolled nucleation. If the seed is added at a temperature too far below saturation, the product may have already nucleated. In either case, the increase in nucleation could result in a decrease in impurity rejection and/or a change in particle size distribution and other physical attributes. 

Curves F-G and H-G represent two different modes of carrying out crystallization by cooling and would be expected to result in two very different results in terms of physical properties—mean particle size (mean dp) particle size distribution (PSD), surface area, and bulk density, as well as possible differences in rejection of impurities and occlusion of solvent. Other differences can include a change of morphology and a potential for changes in polymorph formation. These differences result from the supersaturation and surface... 

It is not clear whether the still higher activities for the reprepared samples are accidental or have something to do with the distribution or location of the promoter. It would be of great interest to perform careful annealing experiments on samples with transmutation products to try to establish the influence, if any, of the location of the impurity atoms. Also, measurements over a series of doses should give important information about the true shape of the activity-concentration curve at low nickel content. 

Sample purity The matter of sample purity is somewhat more complex than might be thought at first. The effect of an impurity on the diffraction pattern depends on its mole fraction in the sample vapor and on its scattering power relative to that of the material of interest. (The structure-sensitive scattering from a molecule is approximately proportional to n//Z,Z//r//.) However, the effect of an impurity on the desired structure determination need not bear much relation to its effect on the diffraction pattern. If the impurity has a distance distribution sufficiently different from that of the substance of interest, the peaks of the D(r) curve will be resolved accordingly, the parameter values of the two molecules will be essentially uncorrelated and the desired results unaffected. On the other hand, small amounts of an impurity with a distance spectrum similar to the substance of interest can seriously disturb the results. It is perhaps worth noting that the... 

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