Shape evolution

D. S. Noh, Y. Koh, I. S. Kang. Numerical solutions for shape evolution of a particle growing in axisymmetric flows of supersaturated solution. J Cryst Growth 183 427, 1998. 

Peng, X. G. (2003). Mechanisms for the Shape-control and Shape-Evolution of Colloidal Semiconductor Nanocrystals. Adv. Mater., 15,459-463. 

Figure 5. Time-dependent shape evolution of Pt multipods in the presence of Ag(acac). (Reprinted with permission from Ref [41], 2005, American Chemical Society.)...

Figure 11. (a-d) Time-dependent shape evolution of Pt-porous nanoparticles at Pt(acac)2 HDD HDA ACA DPE molar ratio of... 

The inhibition-acceleration mechanism. Moffat et al. (37) proposed the inhibition-acceleration mechanism to explain the experimentally observed comer rounding (inversion of curvature. Fig. 19 in Ref. 37) and general shape evolution in superconformal electrodeposition of copper in vias and trenches of nanometer dimensions (37,38). These authors also smdied a three-additive system composed of two inhibitors and one accelerator. They concluded that superconformal deposition and comer rounding may be attributed to competitive adsorption of inhibitor and accelerator. This model is based on the assumption of curvature (in vias and trenches) -enhanced accelerator coverage. 

Aramaki and Atkinson were also active in work on the spiro-oxazines [65]. They noted that for NOSH in many polar and nonpolar solvents the picosecond time-resolved resonance Raman spectra simply built up over 50 psec with no shape evolution. The same finding was concluded from transient absorption measurements over the same time scale. The spectra/absorbances were then constant for 1.5 nsec. These authors suggest that only two isomers can be expected to contribute to the merocyanine spectra because those trans about the y-methene bridge bond attached to the naphthalene ring are sterically crowded due to short interproton distances. There was no evidence for the X transient in their study however, the 50-psec convoluted pulse profile may be expected to mask this sortlifetime species even if it were present. 

The contact wear approach is also applicable to modeling dual material systems such as tungsten polish. The calculated shape evolution is shown in... 

Figure 14.11 shows the shape evolution due to v(n) and its characteristics in Eq. 14.47 for an initially circular particle. After very long times, the only remaining orientations on the growth shape are those that lie on the interior portion of the ((-surface therefore, the portion of the ((-surface with the spinodes (the swallowtailshaped region) is removed. 

W.C. Carter, A.R. Roosen, J.W. Cahn, and J.E. Taylor. Shape evolution by surface diffusion and surface attachment limited kinetics on completely facetted surfaces. Acta Metall., 43(12) 4309-4323, 1995. 

Song. J. M. Zhu, J. H. Yu, S. H. Crystallization and Shape Evolution of Single-Cryslalline Selenium Nanorods at Liquid-Liquid Interface From Monodisperse Amorphous Se Nanospheres toward Se Nanorods. J, Phys. Chem. B 2006.110, 23790-23795. 

Figure 15 (a) TEMs of a CdSe NQD sample dominated by arrow-shaped particles (60% HPA reaction), (b-d) HR-TEMs demonstrating the shape evolution from (b) pencil- to (c) arrow-to (d) pine-tree-shaped CdSe NQDs. (e) Pine-tree-shaped particle looking down the [001] direction, that is, the long axis. Analysis of lattice spacings obtained by HR-TEM imaging revealed that wurtzite is the dominate phase for each shape and that the angled facets of the arrows comprise the (101) faces. (Reprinted with permission from Ref 42. 2000 American Chemical Society)... 

Rod growth dynamics also depend upon the identity of the phosphonic acid. The effectiveness of the phosphonic acid in promoting rod growth depends critically on its steric bulk, or the length of its alkyl chain. Shorter-chain phosphonic acids, such as HPA, more effectively promote rod growth compared to longer-chain phosphonic acids, such as tetradecylphosphonic acid (TOPA). Combinations of longer-and shorter-chain phosphonic acids can be used to readily tune rod aspect ratios and control shape evolution dynamics. 

Elechiguerra, J. L., Reyes-Gasga, J. and Yacaman, M. J. (2006). The role of twinning in shape evolution of anisotropic noble metal nanostructures. J. Mater. Chem. 16 3906-3919. 

Jiang, X. C., Zeng, Q. H. and Yu, A. B. (2007). Thiol-frozen shape evolution of triangular silver nanoplates. Langmuir 23 2218-2223. 

H NMR spectroscopy combined with different techniques (see Section 4.05.3.6) has been used to perform the dynamic characterization of fananserin 35, an anxiolytic drug which can be crystallized as four different polymorphs. The dynamics were monitored by measuring the spin-lattice relaxation and line-shape evolution temperature dependence <2006MI798>. 

Fig. 27. Shape evolution predicted at half of the base current density (otherwise base conditions).

Fig. 28. Shape evolution predicted at base conditions with a wall angle of 70° (otherwise base...

In the preceding cases, the leveling parameter, Alev> was set at zero. Virtually all deviations from uniformity were caused by nonuniform depletion of the metal ion due to concentration field effects. Fig. 30 shows the predicted shape evolution at base conditions with Alev set at 1.0. A dramatic inversion of the earlier effect is... 

The example of interface shape evolution is shown in Eig. 2 as a function of the distance from the point where the liquid was brought into the channel. The pictures on the left side are the experimental data on refrigerant R113 interface shape development obtained for rectangular 2.6x7.1 mm channel in [15]. The laser knife technique was used to record the interface shape. 

He, Y., Braatz, R. and Alkire, R. (2007) Effect of Additives on Shape Evolution during Electrodeposition. I. Multiscale Simulation with Dynamically Coupled Kinetic Monte Carlo and Moving-Boundary Finite-Volume Codes. /. Electrochem. Soc., 154, D230-D240. 

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