Yoshinori Hayakawa has engaged in medical physics. He developed simultaneous neutron monitoring system for Boron-Neutron-Capture-Therapy. He has measured, first in the world, acoustic pulse generated in the body of treated patient by pulsed proton beam. The phenomenon may be used to monitor dose distribution in patients. He is interested in researches on human wellbeing. He has developed Computer Numerals, New Abacus Numerals, Computer Abacus, and Universal Literacy Alphabet for improving basic education to reduce poverty. Many of these can be observed in youtube without payment. He insists use of plant factory and space-based solar electric power generation against global cooling.

Vaccines against Infectious Diseases