Is it infringement to improve on the basis of others' patents?

This should be analyzed in detail, depending on whether the parts involved are within the protection scope of patent claims. If it is explicitly protected in the claim, then the other party's use of this part will definitely constitute infringement. If this part belongs to the existing technology, it does not constitute infringement. For example, if a part claimed in your patent does not exist in the existing technology, then the other party infringes your patent right. If the component is a common component of a circuit in a well-known technology, such as diodes and resistors, and your patent protects a specific electronic circuit composed of these components, then the other party's use of the component does not constitute infringement.