标题： 非均匀不完美流体球对称模型无大爆炸奇点 显示英文标题

标题： Inhomogeneous imperfect fluid spherical models without Big-Bang singularity

摘要： 到目前为止，所有已知的无奇点的宇宙学模型都是圆柱对称的。 这里我们提出了一类新的球对称的非奇异模型，该模型充满非理想流体和径向热流，并满足弱能条件和强能条件。 当$t$很大时，压力和热流的各向异性趋于消失，从而形成完美流体。 该模型中有一个时间的自由函数，可以适当选择以实现非奇异行为，并且存在多种这样的选择。 显示英文摘要

摘要： So far all known singularity-free cosmological models are cylindrically symmetric. Here we present a new family of spherically symmetric non-singular models filled with imperfect fluid and radial heat flow, and satisfying the weak and strong energy conditions. For large $t$ anisotropy in pressure and heat flux tend to vanish leading to a perfect fluid. There is a free function of time in the model, which can be suitably chosen for non-singular behaviour and there exist multiplicity of such choices.