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The space gravitational wave (GW) antennae is more sensitive to the lower frequency GW signals compare with the ground-based GW detectors. The space mission Taiji is designed to detect the GW sources within frequencies between 0.1 mHz and 1 Hz. A preliminary study of Taiji was started in 2008. Up to now, a sophisticated mission design of Taiji have gradually taken shape. The research and development of the key technologies for Taiji is now officially launched. A brief introduction to the analysis and the pre-work of the Taiji technology are given here.

We consider a new generalized Chaplygin gas model that includes the original Chaplygin gas model as a special case. In such a model the generalized Chaplygin gas evolves as from dust to quiessence or phantom. We show that the background evolution for the model is equivalent to that for a coupled dark energy model with dark matter. The constraints from the current type Ia supernova data favour a phantom-like Chaplygin gas model., 8 pages, 3 figures, LaTeX2e, Accepted for publication in Phys. Lett. B

We investigate in this paper the cosmological evolution of a dark energy model with two scalar fields where one of the scalar has canonical kinetic energy and another scalar has negative kinetic energy term. For such a system with exponential potentials we find that during the evolution of the universe the equation of state $w$ changes from $w>-1$ to $w, Comment: 9 pages, 3 figures, LaTeX2e

We present a phase-space analysis of cosmology containing multiple scalar fields with a positive or negative cross-coupling exponential potential. We show that there exist power-law kinetic-potential-scaling solutions for a sufficiently flat positive potential or for a steep negative potential. The former is the unique late-time attractor, but it is difficult to yield assisted inflation. The later is never stable in an expanding universe. Moreover, for a steep negative potential there exists a kinetic-dominated regime in which each solution is a late-time attractor. In the presence of ordinary matter these scaling solutions with a negative cross-coupling potential are found unstable. We briefly discuss the physical consequences of these results., Comment: 9 pages, LaTeX2e

We present a phase-space analysis of cosmology containing multiple scalar fields with positive and negative exponential potentials. We show that there exist power-law multi-kinetic-potential scaling solutions for sufficiently flat positive potentials or steep negative potentials. The former is the unique late-time attractor and the well-known assisted inflationary solution, but the later is never unstable in an expanding universe. Moreover, for steep negative potentials there exist a kinetic-dominated regime in which each solution is a late-time attractor. We briefly discuss the physical consequences of these results., 8 pages, LaTeX2e, to appear in Phys.Lett.B