The phrase "which is doubled" is correct and usable in written English.
You can use it when you want to emphasize the completeness or magnitude of something. For example: "Homework assignments this week have increased, which is doubled from last week."
The photo radar program was started in Denver in 1998 and each ticket carries a $40 fine, which is doubled in school zones.
The effect of buoyancy forces on laminar heat transfer inside a variable width plate-fin heat sink is numerically analyzed: the configuration under investigation comprises an array of rectangular fins, the number of which is doubled at the streamwise middle length of the plate, leading to a stepwise reduction in the respective channel width and hydraulic diameter.
Before each retransmission, the sender needs to backoff for a random duration within a window which is doubled for each failed transmission.
The second friction test on the same nanotubes revealed a COF of 0.057 ± 0.01, which is doubled with respect to the first value.
It is seen that the normalized wakefield amplitude is about 0.35 for negative Gaussian chirped laser pulse in unmagnetized plasma which is doubled compared to unchirped laser pulse in unmagnetized plasma case.
There are about 76,000 cases every year, costing the NHS about £1.4bn to treat - a figure which is doubled when the associated social care costs are taken into account.
The University of Houston, which is doubling its library space, specializes in the publishing of scholarly material online.
MTN controls half of the Nigerian telecoms market, which is doubling in size every year.
We are on set in Magaluf in Majorca, which is doubling for Malia in Crete – the setting for The Inbetweeners' first lads holiday.
Just look at Yammer, which is doubling revenue every quarter.
being eclipsed by the growth in bandwidth, which is doubling every year.
