Distribution bimodal

Figure A3.9.3. Time-of-flight spectra for Ar scattered from Pt(l 11) at a surface temperature of 100 K [10], Points in the upper plot are actual experimental data. Curve tinough points is a fit to a model in which the bimodal distribution is composed of a sharp, fast moving (lienee short flight time), direct-inelastic (DI) component and a broad, slower moving, trapping-desorption (TD) component. These components are shown...

Single molecules also have promise as probes for local stmcture when doped into materials tliat are tliemselves nonfluorescent. Rlrodamine dyes in botli silicate and polymer tliin films exliibit a distribution of fluorescence maxima indicative of considerable heterogeneity in local environments, particularly for the silicate material [159]. A bimodal distribution of fluorescence intensities observed for single molecules of crystal violet in a PMMA film has been suggested to result from high and low viscosity local sites witliin tire polymer tliat give rise to slow and fast internal conversion, respectively [160]. 

Using both condensation-cured and addition-cured model systems, it has been shown that the modulus depends on the molecular weight of the polymer and that the modulus at mpture increases with increased junction functionahty (259). However, if a bimodal distribution of chain lengths is employed, an anomalously high modulus at high extensions is observed. Finite extensibihty of the short chains has been proposed as the origin of this upturn in the stress—strain curve. 

Bimodal Distribution a plot of frequency of occurrence of a variable versus the variable. A bimodal distribution exists if there are two maxima of the frequency of occurrence separated by a minimum. See Mode. 

Biological wastewater treatment processes also affect solids characteristics and hence solids separation. Activated sludge solids have been found to have a distinct bimodal distribution with one mode in the supracolloidal to settleable range and another near the border between the colloidal and supracolloidal fractions. The concentrations and size limits in each range are affected by conditions in the... 

Strontium molybdate (SrMo04) using laser light seattering (Sohnel etal., 1988). Bimodal distributions were observed and the presenee of agglomerates was eonfirmed by mieroseopy (Figure 6.16). 

We have prepared a copolymer-bearing amino side group and used it either alone or in combination with BP to initiate the photopolymerization of MM A [89]. The gel permeation chromatography (GPC) plot of PMMA initiated by the former system showed a bimodal distribution of molecular weight because both the radicals produced initiate polymerization as follows ... 

A bimodal distribution is a frequency distribution of a certain phenotype with two peaks separated by an antimode. 

In another exemplary study, optical microscopy revealed that the void content of resole networks ranged from 0.13 to 0.21.82 Resole networks prepared from different F/P molar ratios showed comparable void size distributions. A bimodal distribution was observed for all networks, which was attributed to... 

Figure 1 and Table 1 show the data obtained using PIB s prepared with the f-BuCl/ Et2AlCl/MeCl system in the -30° to -65 °C range. PIB s prepared in the range from —30° to —45 °C have monomodal MWD while those prepared below -45 °C exhibit bimodal distributions. MWD s broaden with decreasing polymerization temperature. 

A conspicuous finding in these studies is that Et2AlCl-based initiator systems lead to bimodal distributions whereas those with EtjAlBr and Et2All lead to mono-modal distributions. Also, the MWD for Et2AlCl was broader ( 1.4 to 5.9) than those for Et2AlBr ( 1.7 to 2.2) and Et2AlI ( 1.9 to 3.0). A possible explanation for the bimodal MWD is given in Section 5. The reason(s) for the relatively narrow MWD s (<2) of LMWF and HMWF remains obscure. 

PIB s prepared with the r-BuCl or r-BuBr/Et2AlCl systems show bimodal distributions and polymerization does not occur with Et2AlCl in the absence of r-BuX,... 

Polymerization of t-butyl methacrylate initiated by lithium compounds in toluene yields 100% isotactic polymers 64,65), and significantly, of a nearly uniform molecular-weight, while the isotactic polymethyl methacrylate formed under these conditions has a bimodal distribution. Significantly, the propagation of the lithium pairs of the t-Bu ester carbanion, is faster in toluene than in THF. In hydrocarbon solvents the monomers seem to interact strongly with the Li+ cations in the transition state of the addition, while the conventional direct monomer interaction with carbanions, that requires partial dissociation of ion-pair in the transition state of propagation, governs the addition in ethereal solvents. 

Application of Other Forms of F(x). As was mentioned a bimodal distribution with first order deactivation exhibited poor 2... 

In Figure 14(a) the bright-held TEM cross-sectional image of the reference AuAg sample is shown. The size distribution of the clusters has an average diameter = 11.7nm and a standard deviation of the experimental bimodal distribution o- = 6.4nm. The effect of... 

Because of the improvements in properties exhibited by elastomers having bimodal distributions [5], there have been attempts to prepare and characterize "trimodal" networks [56]. The calculations suggest that adding a small amount of very high molecular weight end-linkable polymer could further improve mechanical properties. 

Figure 6 A network having a bimodal distribution of network chain lengths. The short chains are arbitrarily shown by heavier lines than the long chains, and the dots represent the crosslinks, typically resulting from the end linking of functionally terminated chains. 

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