Dear Hiroto Kawakami ,

Your question is not quiet clear. I will try to give you some hints to understand the situation. 1) Please note that ResearchGate (RG) is neither a journal nor a publisher, you cannot "publish" here. It is a platform for papers published in journals and for books and book chapters, or to present unpublished texts, data etc. See also "Is ResearchGate a publisher?" in https://help.researchgate.net/hc/en-us/articles/14292596164753. 2) "Register" is not the right word here. See this help page for instructions how to add published or unpublished research to your RG profile: https://help.researchgate.net/hc/en-us/articles/14293005132305-How-to-add-research. And see the list of your research items that are already assigned to your profile: https://www.researchgate.net/profile/Hiroto-Kawakami/research. 3) You wrote about "materials" - did you mean more than one research item? But you indicated only one DOI. Note that each digital object (e.g. a file with a publication) must have its own DOI. 4) RG creates DOIs only for unpublished research (e.g., preprints), not for publications. 5) 10.13140/rg.2.2.36696 is an incomplete DOI. A typical DOI from RG is 10.13140/RG.2.2.17670.08007.

Kind regards,

Wolfgang Dick