Precise measure of kilogram and ampere

Redefining the kilogram and the ampere
New research using graphene presents the most precise measurements of the quantum Hall effect ever made, one of the key steps in the process to redefine two SI units.

"Key units to be redefined are the kilogram (mass) and the ampere (electric current). Presently the kilogram is defined by a physical lump of platinum-iridium and the ampere is defined via the force produced between two wires.
The goal is to define the kilogram in terms the Planck constant h and the ampere in terms of the electron charge e."

in PhysOrg.com