I am majoring in physical chemistry at university.

He is an expert in nuclear physics.

He is an expert in nuclear physics and has won many awards in the field.

He is an expert in astrophysics, and his research is highly valued around the world.

He is an expert in applied physics.

We should always remember the power of Kannon in difficult times.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.