u235
proton 92 92.669392
neutron 143 144.238952
total = 236.908344
actual = 235.0439299 Da
weight loss = 1.8644141
u238
proton 92 92.669392
neutron 146 147.264944
total = 239.934336
actual = 238.05078826 Da
weight loss = 1.88354774
proton mass 1.007276466621(53) Da
neutron mass 1.00866491588(49) Da
由上可知鈾238的BOnding 能量更高因而更穩定
