Man-madestatic magnetic fields are generated wherever DC currents are used, such as in electric trains or industrial processes such as aluminium production and in gas welding.
在使用直流电的地方即产生人为的静电磁场，例如在电车或诸如铝生产和气焊等工业操作程序中。
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It can be caused by a build-up of static electricity indoors from carpets or clothing made of man-made fibres, or from TV sets, duplicators or computer display screens.