For a silicon diode with long P and N regions, the accepter and donor impurity concentrations are 1 ×  and 1 ×  , respectively. The lifetimes of electrons in P region and holes in N region are both 100 µs. The electron and hole diffusion coefficients are 49  and 36 , respectively. Assume kT/q = 26 mV, the intrinsic carrier concentration is 1 × , and q = 1.6 × C. When a forward voltage of 208 mV is applied across the diode, the hole current density (in nA/) injected from P region to N region is _____________.