1. For the completeness of the explanation or paper, but it is harmful to the processing and logic of the text when compiled into the text, such materials include more detailed descriptions of information research methods and technologies than the text, which is of important supplementary significance for understanding the main content;

2. Materials that are inconvenient to be included in the text because they are too large or the materials come from replicas;

3. Some important raw data, mathematical derivation, calculation programs, notes, block diagrams, statistical tables, printer output samples, structural drawings, etc.

4. Generally speaking, appendices generally contain complex information and huge data, and it is necessary to add appendices especially when journals have requirements on the length of words. Even so, the contents in the appendix should be concise, and don't put any information that is not directly related or important to the text.