Kentucky's Mammoth Cave National Park is known for housing the world's longest cave system, which stretches 400 miles. Though famous for its caves, the park also has more than 70 threatened or endangered species that include birds, crustaceans, and fish. It is believed that the first human ...
3D 打印在原有打印技术的基础上,获取了新的打破,它将计算机设计出的物体分解成若干层平面数据,而后形成一个平面形状,再经过层层积累叠加,生成一个新物体。 2013 年 6 月,美国某医学中心利用该技术打印出一颗人类的心脏,并使这 个心脏能像正常心脏那样跳动。这再次印证了 ( )