  Whether a scientific paper is cited is related not only to the influence of
its author(s) but also to the journal publishing it. Scientists, either
proficient or tender, usually submit their most important work to prestigious
journals which receives higher citations than the ordinary. How to model the
role of scientific journals in citation dynamics is of great importance. In
this paper we address this issue through two folds. One is the intrinsic
heterogeneity of a paper determined by the impact factor of the journal
publishing it. The other is the mechanism of a paper being cited which depends
on its citations and prestige. We develop a model for citation networks via an
intrinsic nodal weight function and an intuitive ageing mechanism. The node's
weight is drawn from the distribution of impact factors of journals and the
ageing transition is a function of the citation and the prestige. The
node-degree distribution of resulting networks shows nonuniversal scaling: the
distribution decays exponentially for small degree and has a power-law tail for
large degree, hence the dual behaviour. The higher the impact factor of the
journal, the larger the tipping point and the smaller the power exponent that
are obtained. With the increase of the journal rank, this phenomenon will fade
and evolve to pure power laws.
