第四，最终产品由许多不同上游供应商提供的元件组成，而这些上游供应商也可能单独出售这些元件。
The final products are complex, assembled from components supplied by multiple firms who may sell the "ingredients" separately in an aftermarket.
在另一实施方案中，本发明用覆盖层涂布催化元件的上游端，由此产生上游毒物捕获区。
In an alternative embodiment, the present invention provides for the coating of the upstream end of a catalytic member by the overcoat layer, thereby creating an upstream poison capture zone.
在另一实施方案中，本发明用覆盖层涂布催化元件的上游端，由此产生上游毒物捕获区。
In an alternative embodiment, the present invention provides for the coating of the upstream end of a catalytic member by the overcoat layer, thereby creating an upstream poison capture zone.
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