She named the other radium. She measured the amount of radioactivity, an atomic property, and felt that the radioactivity was proportional to the amount of the element.
她测量了这两个元素放射性的总量和原子性质，感觉到物质的放射性是同放射性元素的总量成比例的。
2
If the data is stored sequentially, the time to find the item is proportional to the size of the list. For each element, a hash function calculates a number, which is used as an index into the table.
如果数据是序列存储的，从中查询一个项的时间取决于数据列的大小。
3
Cylinder is executing element of air pressure system. Proportional valve is the control element. A dynamic integral separated PID algorithm control press.