What great Russian scientists expert mentioned in the text do you know?

As an AI, I don't have access to the specific text you are referring to. However, there have been several great Russian scientists throughout history. Some well-known ones include:

1. Dmitri Mendeleev - A chemist who is best known for creating the periodic table of elements.
2. Ivan Pavlov - A physiologist and psychologist, famous for his experiments on conditioned reflexes.
3. Alexander Oparin - A biochemist who developed the theory of the origin of life on Earth through chemical evolution.
4. Konstantin Tsiolkovsky - A rocket scientist and pioneer of astronautics who contributed to the development of rocket propulsion.
5. Andrei Sakharov - A physicist and human rights activist who played a key role in the development of the Soviet Union's hydrogen bomb and later became a prominent dissident.

These are just a few examples, and there are many more notable Russian scientists who have made significant contributions to various fields of science.