IEEE Research Team Puzzle

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Across
  1. 2. The green glow off nuclear waste.
  2. 4. An idea of explanation that you then test through study and experimentation.
  3. 7. The cipher device used by nazis in WW2 ?
Down
  1. 1. the name of a famous scientist and also the name of a very prestigious research institute located in Germany ?
  2. 3. a popular constant in mathematics.
  3. 5. Name of the first computer.
  4. 6. Knowledge or study of the natural world based on facts through experimentation.