"dense concentration" is a perfectly valid phrase in written English.
You can use it to refer to a situation where something is concentrated and highly concentrated, particularly within a limited space. For example, you could say "The dense concentration of people in the square was almost overwhelming".
Other artists view the essence of the city as sprawl rather than dense concentration.
The resulting dense concentration of high-end business decision-making spawns whole industries to service it.
In the predawn, it is almost as if the emotion has been boiled down to its most dense concentration.
It has a dense concentration of historic sites, all in their original locations and all in nearly their original condition.
For the latter, Wuzhen has a conveniently dense concentration of restaurants.
In 2012, she had compiled a report on the town, because it seemed to have a particularly dense concentration of Herbalife nutrition clubs relative to its population.
Under favourable conditions, cyanobacteria can reproduce at explosive rates, forming dense concentrations called blooms.
The drawings reflect this aerodynamic perversion: dense concentrations of swooping lines that flatter a rear suspension, say, and suggest something more on the order of a space shuttle.
Guangdong Province in southern China, where the illness is believed to have emerged late last year, has dense concentrations of domestic waterfowl in close proximity to pigs and people.
Some parts of the test area are flat ice sheets studded with occasional, distinct rocks while others are moraines, dense concentrations of rock and rubble deposited by glaciers.
The new work, O'Hern says, demonstrates a method for actually producing such material with dense concentrations of nanometer-scale holes over large areas.
