Seeded growth

The synthesis of spherical nanoparticles using the mediated seeded-growth method has been carried out using different mild reducing agents such as citrate, organic acids or hydroxylamine and well-defined monodisperse seed particles. 

Au nanorods with tunable aspect ratio can also be synthesized in aqueous solution using surfactants and controlling the growth conditions of seed nanoparticles. High 

It is also known that the presence of AgN03 enables better control of the shape and yield of Au nanorods. The proposed mechanism is related to an adsorption of Ag+ 

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Environmental impact studies on NE have been performed. Although undiluted NE inhibits seed growth, no effect on plant growth was observed when exposed to 6, 000 ppm-min of NE and only minor effects were observed at the 60, 000 ppm-min exposure level (41). Exposure of microbial populations to 25% NE in air for seven hours showed normal growth. NE is not an o2one-depleting gas (20). 

The growth of the nanoparticles could have occurred either by the growth of CdSe on the seeds (growth from supersaturated solution) or by the process of Ostwald ripening whereby larger seed grow at the expense of the smaller ones. 

The seeding-growth procedure is a popular technique that has been used for a century to synthesize metal particles in solution. Recent studies have successfully led to control the dimensionality of the particles where the sizes can be manipulated by varying the ratio of seed to metal salt [23-25]. The step-by-step particle enlargement is more effective than a one-step seeding method to avoid secondary nucleation [26,27]. This mechanism involves a two-step process, i.e. nucleation and then successive growth of the particles as illustrated in Scheme 1. 

Experiment II. Volatile compounds from leaves and bulbs Volatiles (terpenoids, ethylene and other compounds) can be released from the leaves and other plant parts and consequently can affect the germination of seeds, growth and development of neighbouring plants in ecosystems. 

Calcium phosphate precipitation may also be involved in the fixation of phosphate fertilizer in soils. Studies of the uptake of phosphate on calcium carbonate surfaces at low phosphate concentrations typical of those in soils, reveal that the threshold concentration for the precipitation of the calcium phosphate phases from solution is considerably increased in the pH range 8.5 -9.0 (3). It was concluded that the presence of carbonate ion from the calcite inhibits the nucleation of calcium phosphate phases under these conditions. A recent study of the seeded crystal growth of calcite from metastable supersaturated solutions of calcium carbonate, has shown that the presence of orthophosphate ion at a concentration as low as 10-6 mol L" and a pH of 8.5 has a remarkable inhibiting influence on the rate of crystallization (4). A seeded growth study of the influence of carbonate on hydroxyapatite crystallization has also shown an appreciable inhibiting influence of carbonate ion.(5). 

Xomeritakis, G., Nair, S., and Tsapatsis, M. (2000) Transport properties of alumina-supported MFI membranes made by secondary (seeded) growth. Micropor. Mesopor. Mater., 38, 61-73. 

MFI membranes made by secondary (seeded) growth. J. Memhr. Sci., 182, 103-109. 

M. (2001) Separation of xylene isomer vapors with oriented MFI membranes made by seeded growth. Ind. Eng Chem. Res., 40, 544-552. 

First, for the case in which only solute concentration measurements are available, pseudo-experimental data are simulated and used in the parameter estimation scheme. Even with noise-free data, the recovered parameters differ greatly from the true parameters and the uncertainties of the nucleation parameters are large. This indicates that there exists a large set of quite different b and ki, pairs that would lead to very similar solute concentration profiles. The insensitivity of the objective function to the nucleation parameters can be attributed to the fact that the mass of a nucleated particle is almost negligible and the change in the solute concentration is primarily due to seed growth. 

In such seeds, but not in whole seeds, growth of embryonic tissues (roots and shoots) was inhibited after the breaking of the inner seed coats. Nevertheless, caffeine increased more in such roots of the seedlings of decoated seeds than in roots of normal seedlings. 

Metal oxide nanotubes have been synthesized by a diverse variety of fabrication routes. For example titania nanotubes, and nanotube arrays, have been produced by deposition into a nanoporous alumina template [48-51], sol-gel transcription using organo-gelators as templates [52,53], seeded growth [54], hydrothermal processes [55-57] and anodic oxidation [58-65]. 

Cao L, Liu Z, Zhu T (2006) Eormation Mechanisms of Non-Spherical Gold Nanoparticles During Seeding Growth Roles of Anion Adsorption and Reduction Rate. J Colloid Interface Sci 293 67-69... 

Huang MH, Kuo C-H (2005) Synthesis of Branched Gold Nanocrystals by a Seeding Growth Approach. Langmuir 21 2012-2016... 

In Ref 13, a new approach toward the preparation of Au(lll) nanoisland-arrayed electrode based on fine colloidal nanolayer-directed seeding growth has been presented. 

The formation of primary nanometer-sized subunits, as an intermediate step in the growth reaction, can also account for the observed induction period that was observed in the seeded growth experiments (13,38,56,57). The condensation reaction can proceed parallel to the hydrolysis reaction from the very first beginning, and still it will take a certain time (induction time) to produce the primary subunits, which then may agglomerate to form the new seed nuclei or, in the case of seeded growth, adhere to the surface of already existing particles. 

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