Monomodal distribution

PIB s prepared using r-BuI/Et2AH show monomodal distribution but slow polymerization occurs even in the absence of purposefully added r-BuX. 

By way of contrast di-t-butylmagnesium gave polymer of broad monomodal distribution of molar mass 101 over the whole range of THF concentration. 

Figure 1. Example of compositionally resolved bimodal and monomodal distributions of aerosols. The ordinate gives the percent of the species found in the given size fraction of the impactor. The mode near 0.3 xm is the accumulation mode , and that above 8 xm is the coarse mode The minimum of mass between 1 and 2 xm is typical the chlorine distribution is anomalous. Chlorine is in fact a coarse-mode marine aerosol that has lost its larger particles during transport from the ocean to Davis, California, a distance of roughly 100 km. (Reproduced with permission from reference 15. Copyright 1988.)...

PDI and the modality of MMDs also strongly depend on ci/ Nd-ratios and on the catalyst systems used. Catalyst systems which yield monomodal distributions at low ci/ Nd-ralios and broad distributions which are often bimodal at high ci/ Nd-ratios are based on NdV/DIBAH/SiCl4 [187], NdV/DIBAH/EASC [191] and Nd(IOPr)3/DIBAH/tBuCl [232],... 

Even though the lifetime distributions appear to be quite different, the recreated data are almost identical except for a small deviation near 200 ns and less obvious ones at shorter times. If the relative differences are plotted, systematic differences beyond the statistical noise are noticeable up to 200 ns, particularly when several channels are binned together. Given sufficient statistics, in principle, one can tell the difference between a bimodal and a monomodal distribution. The shown simulated spectra are based on 108 counts, five to 10 times the amount collected for the data discussed here. 

The secondary electron images of fractures provide direct access to the size and shape of the pores. Figures 7.18 and 7.19 illustrate two types of textural mesoporosity the first is characterised by a monomodal distribution centred on 10 nm and the second by a wider pore size distribution from 5 to 30 nm. 

The results are summarized In Table III. Narrow, monomodal distributions were seen, with Mw/Mn <1.1. The Mn correlations with Intrinsic viscosity In toluene were plotted In Figure 4. Since viscosity average molecular weight (M ) depends upon a, an Interactive procedure was used to arrive at final values of a. The following Mark-Houwlnk equations were thus derived from least squares fit ... 

Richard et al. studied a model Pt/Al203 catalyst by transmission electron microscopy and Auger electron microscopy. Oxygen treatments under industrial catalyst regeneration conditions transform a monomodal distribution of platinum particles (mean diameter 1.8 nm) into a bimodal distribution consisting of a phase of particles 10 to 40 nm in diameter and a phase of very small clusters (diameter <1 nm). This observation of stable small clusters is direct evidence for platinum catalyst support interaction. An exchange of water between particles that operate on a molecular scale and might include platinum oxide is postulated. 

The microstructure of the green body as observed by SEM is shown in Fig. 4. After consolidation, powders in green body compact closely and homogeneously. However, the polymer network was not observed via SEM. The pore diameter distribution, obtained by Hg intrusion porosimetry, showed a monomodal distribution type. The relative density, porosity, and the median pore diameter of green samples were 57.67%, 35.02%, and 10.6nm, respectively. 

Reported polymer yields of 60-80% are much higher than by the Wurtz-coupling synthesis, and the resulting polymers have M values in the range of 10 -10 depending on the amount of RLi used to initiate the polymerization. Furthermore GPC profiles reveal a monomodal distribution of molecular weights and polydispersities between 1.2 and 1.9. 

If we perform kinetic experiments with a constant mass of metal (iv) of a given density (p), in the form of colloidal parhcles having a monomodal distribution, we can correlate the radius value (r) to the achvity by considering the following equahons ... 

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