沃尔沃卡车:车展之外的精彩

活动中,沃尔沃限量版FH车型Time Machine(时间机器)首次在中国亮相,并作为此次节油评选的比赛车辆,这令所有在比赛中得以驾驶这款卡车的驾驶员倍感兴奋。     

花花公子的时间机器

几乎所有人对于阿斯顿·马丁这个品牌都有一个共识——花花公子之车！只有那些超级有钱，又对生活充满了激情的人才会对它趋之若鹜。     

Time-machine in perfect fluid cosmologies

This letter investigates the time-machine problem in perfect fluid cosmologies. It solves the Einstein's field equations with the energy-momentum tensors for perfect fluid and constructs a class of time-machine solutions,by which the time-machine problem in the perfect fluid cosmologies is solved.