nuclear

radiation

radiation


        In  physics,  radiation  is  a  process  in  which  EM waves  travel  through  a  vacuum  or  through matter-containing  media;  the  existence  of  a  media to  propagate  the  waves  is  not  required.


Tips：
vacuum：an empty area or space
matter-containing：not empty...
EM：electromagnetic(电磁的)
propagate：spread


Ralated  knowledge：

  1. Radiation  is  widespread  in  our  daily  life,   any  object  does  have  radiation.
  2. Most  of  the  radiation  is  harmless,  such  as  radio waves,  visible  light,  and  the  infrared(红外)  waves …
  3. Well,  some  of  them  can  also  be  fatal.  For  example,  the  nuclear  radiation.

WHAT IS NUCLEAR

RADIATION?

        In   physics,  the  nuclear  radiation   was  called  radioactive decay,  also  known  as  nuclear  decay  or  radioactivity,  is the process  by  which  a  nucleus  of  an  unstable  atom  loses energy  by  emitting  particles(粒子)  of  ionizing(电离)  radiation. 

Tips：
decay：become weaker or less good  (衰变)
unstable：likely to change, unsettled   (不稳定的)
emitting particles of ionizing radiation：电离辐射放出粒子



        Alpha  decay  is  one  example  type  of  radioactive  decay, in  which  an  atomic  nucleus  emits  an  alpha  particle,  and thereby  transforms  (or 'decays')  into  an  atom  with  a  mass number(质量数)  decreased  by  4  and  atomic  number(原子序数) decreased  by 2. 


some  beneficial  uses

  • Medicinal,  such  as  radio  therapy(放疗)  and  X-rays
  • In  smoke  detectors  (do you remember that boy？)
  • In  tracing  locations  of  gas  or  liquid  leaks  or
  • Tracing  locations  of  malfunctioning  in  the  body (isotope)
  • Sterilization(消毒)  of  medical  instruments  or  bacteria  or moulds(霉菌)  in  foods  (ultraviolet light) 


printf("制作人(不分先后)：\n");

cout<<"李敏成"<<endl;

echo "徐瑞阳"

print "张全琛"

sys.stdout.write("Thanks For Watching!")

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