Aggregate characterization

Analytical calculations of the aggregation process kinetics in terms of this approach are presented in [67, 68]. It is shown there that the aggregation occurs only if the distinctive dimensionless parameter )/) is positive  

It gives the critical dose rate (irradiation intensity) pc as a function of the elastic interaction between similar defects and the temperature  

The critical dose rate pc necessary for initiating the aggregation process is the smaller, the lower the temperature, the stronger elastic attraction of similar particles and the slower the diffusion (greater the activation energy for hopping). This conclusion is in a complete qualitive agreement with the results obtained recently in terms of a quite different mesoscopic approach [63-65]. 

To get the reference point for many-particle effects in defect accumulation, the saturation concentration, n(f oo) could be taken from equation (7.1.58) with (7o C 1, i.e., in the linear approximation neglecting many-particle effects 

Note that this concentration is governed by a sum of diffusion coefficients, D + D j, which practically equals D since vacancies have much lower mobilities compared to interstitials. In the temperature range of high mobilities the value of usually exceeds tq not more than a factor 2-3 and C 1, that is, no 1/3 /f 1. In the regime of intensive aggregation one can expect no to be considerably lower than this estimate due to disappearance of single defects in their aggregates. 

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There are two main kinds of dye aggregates, characterized by their typical spectral properties J-aggregates and H-aggregates. The absorption band maximum (f-band) of the J-aggregates is shifted bathochromicaHy with respect to that of an isolated molecule (M-band) the absorption maximum of the H-aggregates is shifted hypsochromicaHy (H-band). The dyes can also form dimers with a shorter absorption wavelength (D-band). 

In the case of amphiphilic molecules, characterized by the coexistence of spatially separated apolar (alkyl chains) and polar moieties, both parts cooperate to drive the intermolecular aggregation. This simple but pivotal peculiarity makes amphiphilic molecules soluble in both polar and apolar solvents and able to realize, in suitable conditions, an impressive variety of molecular aggregates characterized by spatially separated apolar and polar domains, local order at short times and fluidity at long times, and differences in size, shape (linear or branched chains, cyclic or globular aggregates, extended fractal-like molecular networks), and lifetime. 

S. Colombie, A. Gaunand, M. Rinaudo, and B. Lindet, Irreversible lysozyme inactivation and aggregation induced by stirring kinetic study and aggregates characterization, Biotechnol. Lett. 2000, 22, 277-283. 

Diffusion-controlled particle aggregation under permanent source 7.2.2 Aggregate characterization... 

Exactly 10 years after the previous statement appeared, the first lithium enolate crystal structures were published as (5) and (6). Thus, structural information derived from X-ray diffraction analysis proved the tetrameric, cubic geometry for the THF-solvated, lithium enolates derived from r-butyl methyl ketone (pinacolone) and from cyclopentanone. Hence, the tetrameric aggregate characterized previously by NMR as (7) was now defined unambiguously. Moreover, the general tetrameric aggregate (7) now became embellished in (5) and (6) by the inclusion of coordinating solvent molecules, i.e. THE. A representative quotation from this 1981 crystal structure analysis is given below. 

Microscopy remains the benchmark technique against which most others are compared, especially for particle sizing. It is particularly useful for identifying interparticle interactions and associations, specifically for floe or aggregate characterization and determination of floe morphology, which are difficult using other techniques. Therefore, microscopic methods are discussed in more detail than other methods. 

In our study, no macroaggregates were found after experimental models were suspended in water. However, the various clayAf/- or Fe-/polyphenol interactions produced aggregates characterized by widely different texture and mechanical stability, as evaluated by the Particle-Size Distribution (PSD) of the solid phases determined before and after sonication treatments. 

It is appropriate to consider the multiphase systems as composed of a matrix and concentration-dependent dynamic clusters or aggregates characterized by specific strength, a, the aggregate relaxation time, Xy, and the cluster size polydispersity index, w w 0.2 — 1.0 [44]. Thus the apparent shear stress may he expressed as ... 

Palmer, AG and Thompson, NL, Molecular aggregation characterized by high-Order autocorrelation in fluorescence correlation spectroscopy Biophysical Journal 52 (1987) 257-270,... 

Furthermore, referring to the (quasi-statistical-mechanical) multiple equilibrium description of aggregation, for each aggregate characterized by a cer-... 

Figure 1. Scanning electron microscopy images of the a nanocomposite samples. The PUl (on left side) and PU2 (on right side) polyurea M0S2 nanocomposites. These images clearly show a non uniform dispersion of the nanotubes, forming aggregates characterized by...

As a first step toward a model of mutual interaction of fluids and aggregates, the steady-state condition, with aggregates fixed in space, is used, where forces and torques now can be determined with satisfactory accuracy. For aggregate shapes to be compared, two different samples were chosen. In their work, Ftarshe et al. [37] investigated fom different sorts of aggregates characterized by their... 

S. Takagi, T. Shimada, T. Yui, H. Inoue, High density adsorption of porphyrins onto clay layer without aggregation characterization of smectite-cationic porphyrin complex, Chem. Lett. 30, 128-129 (2001). 

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