The ECG machine uses the negative pole as zero reference.

心电图机使用负极作为零参考。

Lead I uses the Right Arm as the negative pole and Left Arm as the positive pole, forming a vector that goes to the right.

I导联将右臂作为负极，左臂作为正极，形成一个指向右侧（左臂）的向量。

On NordLink, special vessels were used to lay  the cable, which weighs up to 70kg per metre and consists of two parallel strands  — for the positive and negative poles.

在 NordLink 上，使用特殊容器铺设电缆，电缆每米重达 70 公斤，由两条平行股线组成——分别用于正极和负极。