  In connection with the semi-inclusive polarized DIS, it is proposed to
consider the first Melin moments $\Delta q$ of the polarized quark and
antiquark densities, instead of the respective variables $\delta q(x)$, local
in Bjorken x themselves. This gives rise to a very essential simplification of
the next to leading order (NLO) QCD and, besides, allows one to use the
respective QCD sum rules. An expression for $\Delta\bar{u}-\Delta\bar{d}$ in
NLO is obtained which is just a simple combination of the directly measured
asymmetries and of the quantities taken from the unpolarized data.
