The Beijing Zoo, for one, has opened a much larger elephant enclosure and replaced the concrete in its otter exhibit with natural materials and waterfalls.

北京动物园有建造一个很大的大象围场，取代用混凝土修筑，在里面还有水濑在自然的环境和人造瀑布下表演。

For the natural convection in enclosure under permanent magnetic gradient field, the way to generate different magnetic accelerations by different magnetic field arrangements is developed.

针对永磁梯度磁场作用下封闭腔内的自然对流换热，提出通过不同磁场布置产生不同磁加速度的方法。

A place, especially an indoor enclosure, for keeping and raising living animals and plants under natural conditions for observation or research.

动物园，植物园尤指户外的封闭性场所，用于在自然条件下饲养观察和研究用的存活动物和植物。