竺可桢日记>19501122

11月22日 星期三 北京晨阴 40° ,日中阴。

周外长抗议麦克阿瑟非法释放日本甲级战犯重光葵(原徒刑七年)。晚和王淦昌约请顾功叙夫妇、王序夫妇。

晨六点半起。八点十分到院。阅英Atomic Scientist1950年八月份。并嘱图书馆毛君购美国Bulletin01Atomic Sc., American me凡01Sc。8th Ed.及New AdvancedAtlω,。上午开行政讨论会,通过预算1951年及二局(计划和联络局)及办公厅如何合并办公事,通过西文名称(各所)。下午二点半到院。晚和王淦昌约请顾功叙夫妇、王序夫妇、吴正之夫妇及何泽慧、彭桓武。彭赴清华,至膳后来。

Aωmic Scientists News , London , August ,1950。p.13:1curie of any rad10active substance , there 町e 3。7 X1010nuclear disintegrat10nsper sec.The actual m勘s of an element equivalent to1curie depends < upon)on m脑s of atoms , the half-life , and on the extent to which the rad10active formis dilutedwith stable isotopes.For radium, wi也a half-life of1,

600 ye脯, and where everyatomis liable to decay,1curie corresponds to veηnearly1gram.For an isotope suchas10dine131, with half-life of8 days,1curie corresponds to only8 rnicrograms.It ise嗣Y to detect at10-9cu肘, as little as10-14grarn of10dine131can be detected。Page20: Experience has enabled an estirnate to be made of the amount of radiat10nwhich the hurnan body 响11stand without being effected is0。5r?ntgen per week.1r?ntgen is roughly the dose received in1hour at distance of1metre from1gramofJradium。