focal plates, reticles
焦点板，标线片

• Heisenberg uncertainty principle
• Heisenberg uncertainty relation
• Hektor lens
• helfical fibre
• Heliar lens
• helical
• helical band
• helical bevel gear
• helical eyepiece
• helical flash lamp
• helical flash tube
• helical flute
• helical gas lens
• helical lampl
• helical line
• virtual value
• virtual work
• viscid
• viscidity
• viscoelastic
• viscoelasticity
• viscometer
• viscoscope
• viscosimeter
• viscosity