The ratio of the silver-109 isotope to silver-107 turned out to be much higher in New World silver than in the European COINS.
109同位素银和107同位素银在新世界银的比例要比来自欧洲的银币高很多。
The crust granites have higher lead isotope ratios and are richer in uranium lead but poorer in thorium lead.
壳型花岗岩具较高的铅同位素比值和富铀铅贫钍铅的特点；
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