The phrase "aggregates of about" is correct and usable in written English.
It can be used when discussing quantities or collections that are approximately a certain amount.
Example: "The study found aggregates of about 500 species in the region."
Alternatives: "collections of approximately" or "groups of around".
This shows the formation of aggregates of about 200-nm size.
Meanwhile, aggregates of about ~80 nm were detected in presence of PAMAM-OH dendrimers.
Spherical and dispersed aggregates of about 20 nm in diameter were observed by a transmission electron microscope.
A rope-like configuration with aggregates of about 50 nm in diameter indicated that PVA nanoparticles formed well in a mixed solvent of water/acetone (Fouad et al. 2016; Zhang et al. 2007; Yao et al. 2009).
High-magnification images also showed the presence of flower-like aggregates of about 300 400 nm in diameter constituted by radiating nanocrystals.
Smaller aggregates of about 40 nm could also be observed, but isolated primary particles of about 16 nm were not found in any of the micrographs.
There are more than 1,900 rivers within the basin, with an aggregate length of about 112,000 miles (180,000 km).
Immobilised Pt particles (most probably, small uniform aggregates) with dc of about 4.5 nm and a spread of size distribution ca. 1.5 nm demonstrated pronounced adsorption of hydrogen and oxygen similar to pure Pt materials, high electrocatalytic activity with respect to formic acid oxidation as well as a relatively high tolerance towards CO poisoning.
Going into 2015, non-classified national investments in quantum computing reflected an aggregate global spend of about $1.75 billion USD, according to The Economist.
The incidence of the disorder has remained stable over the past 30 years [ 1] with an aggregate worldwide incidence of about 10.5 per 100,000 person-years [ 2].
By contrast, using our software package to extract these positions took around 12 hours of computer time, but only an aggregate of about 3 man-hours of labor.
