unity can't add reference CLR DLL

I use vs2005 to build the ClR, And add it to the Path("Assert/Plugins/x64"). Then, I use VS2015 to add referece ClR int the project, build it successfuly. But When I Run unity, the unity show " The type or namespace name 'Noah' could not be found. Are you missing a using directive or an assembly reference?" How can I resolve it?