If the emulator is programmed to use the extra memory then yes, they Will work with opera ram expansion.
But do not expect any kind of performance improvements by having one of those installed.
Unlikely the N64 expansion pak where If you install It then the system magically detects the extra RAM and the game can use It simply by allocating memory through malloc, the DS expansion pak do not work in that way.
Instead, what you have is a address range that is ucontinuous from the main RAM that is available for you to write only in 16-bit writes. That alone is enough for any software wanting to use the expansion pak to be a struggle. Furthermore you can not read with the ARM9 and the ARM7 there simultaneously, making It even more annoying If you decide to use It as a cache RAM for assets. This plus the fact that this memory range is not covered by malloc results in an increasingly chalenge to any programmer that wants to take advantage of It.