Growth unimodal

This is the special form which f. in Eq. (10) must take for y. to be constant during diffusion-limited growth. It corresponds to a unimodal particle size distribution characterized by the two constants k/B and A/B. ... 

It was found that excitation of the samples during the growth process with a second narrow-band light source corresponding to the kn, of either the in-plane or out-of-plane quadrupole SPR halted the nanoprism fusion so that a unimodal growth occurred. As can be seen in Figure 11.55 [109], this resulted in the formation of a single... 

As a result, the multimodal distribution, occurring for the apparent thickness 2.4 nm, transforms into the unimodal one. This is a proof of conversion of the deposition character at a certain stage of the coating growth. The non-stationary deposition phase, observed during the very onset of the coating formation, is attributed... 

Also discussed are precipitation specific experimental techniques, such as supersaturation measurements, constant composition (CC) method, instantaneous mixing devices, maximum (critical) growth rate experiments, and sizing. Due to the intrinsic difficulties with the direct supersaturation measurements and the microsecond characteristic time scale of precipitation reaction and nucleation, the CC method is used to study the precipitation kinetics. For the same reasons, the critical growth experiments are used to delineate the domain of the reactant feed rate that assures a renucleation-free process and a unimodal CSD. 

As E is decreased one observes a change from the unimodal distribution for subcritical clusters to a bimodal form indicating growth of supercritical clusters. Because the system is adiabatic, the biomodal distributions also represent stationary states in which there are maximum supercritical cluster sizes, which, if exceeded, result in destruction of that supercritical cluster size new bonds formed in the system increase the cluster kinetic energy and decrease the pressure of the monomer gas. In the future it would be desirable to extract from the molecular-dynamics calculation accurate values for the free energy of formation of clusters. Such calculations would resolve the differences between the B - D theory and the Lothe-Pound theory. In the future, molecular-dynamics calculations should make possible development of correct mesoscopic and microscopic theories of homogeneous and even heterogeneous nucleation. 

Anraku Y, Kishimura A, Yamasaki Y, Kataoka K. Living unimodal growth of polyion complex vesicles via two-dimensional supramolecular polymerization. J Am Chem Soc 2013 135(4) 1423-9. 

The unimodal, close to Gaussian, molecular weight distribution of the linear fraction of the polymer obtained by polymerization in the presence of an excess of Me3Si03SCF3 results not from one directional growth of macromolecules, but from a fast randomization of chain ends, according to reactions 5-9. 

Some models of micelle growth take into account the fact that the surfactants located in the part connecting the cylindrical body of rodlike micelles to the endcaps are at a still higher chemical potential than those in the endcaps. This leads one to predict the existence of a second critical concentration, sometimes referred to as second cmc, above which micelles start growing. It also leads one to predict the coexistence of spherical and rodhke micelles, i.e., a bimodal distribution of micelle sizes. This is in contrast to the two-chemical potential approach that predicts a continuous growth of all micelles and a unimodal size distribution curve. 

Figure 3.20 Unimodal growth, (a) A beam excitation waveiength (d-f) TEM...

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