  We study the semi-holographic idea in context of decaying dark components.
The energy flow between dark energy and the compensating dark matter is
thermodynamically generalized to involve a particle number variable dark
component with non-zero chemical potential. It's found that, unlike the
original semi-holographic model, no cosmological constant is needed for a
dynamical evolution of the universe. A transient phantom phase appears while a
non-trivial dark energy-dark matter scaling solution keeps at late time, which
evades the big-rip and helps to resolve the coincidence problem. For reasonable
parameters, the deceleration parameter is well consistent with current
observations. The original semi-holographic model is extended and it also
suggests that the concordance model may be reconstructed from the
semi-holographic idea.
