What should I do if someone published my old reserarch result without mentioning my name?
I would first contact the individual who published your work. Perhaps he can provide insight into his actions.

If he has a faculty position in the US, you could next contact his department to open a case with them. University administration may also be able to step in and arbitrate on the matter.

If the journal is reputable, they too would be a point of contact. Since I have no way of knowing what journal/"journal" this work was published in, it is difficult for me to gauge what contacting the journal would lead to. 

Much of this will depend on providing evidence that you performed the work you say you did. This also greatly hinges on what exactly this person published that you think is yours. Did he publish written work verbatim from your own writings? Did he just publish a paper using an idea you had but never formalized? Did he publish data that you collected? Do you have any lab notebooks showing that you collected the data? Were you paid to do research for this person? Is he publishing a paper using data that you collected, but that he cleaned and analysed?

One note on pursuing civil litigation on this matter: Unless you can show loss of money, opportunity, or standing due to this person's actions, you are extremely unlikely to get a definitive decision awarding you some sort of remuneration for your work. This is not how civil suits work. This is an academic matter and the courts are likely not going to hear the case. (Unless you go to some sort of TV 'Judge Judy' court). If you have an actual published piece of work that is copyrighted, civil action could be a move of last resort. Otherwise, civil action is very unlikely to result in anything.