Abstract
We study the transport phenomenon in a one-dimensional system of interacting electrons with a single weak barrier. We calculate the effective action for the impurity part by path integral, then using effective action to calculate the conductance of the system without any impurity. Influence functional is then used to include the system-environment interaction, so we can calculate the effect caused by the single weak impurity. The result shows that the conductance has different dependences depending on the relation between applied voltage and temperature. When bias is small, conductance becomes a constant; when bias is large, conductance has a power dependence on voltage.