Further separation was carried out by ion exchange, yielding a certain isotope of curium.

Mr. Basayev said it was full of cesium, a radioactive substance that in certain isotopes can be produced as waste from atomic energy plants.

One method analyzes DNA; the other analyzes ratios of certain isotopes.

Most of these applications exploit the property of certain isotopes of californium to emit neutrons.

Natural radioactivity is the spontaneous decay of the atoms of certain isotopes into other isotopes.

First, these technologies are less well-defined than nuclear weapons: because current nuclear technology demands certain isotopes of rare metals, it is distinct from other activities.

"Nor would your Stone Age friend understand if you explained how a few hydrogen atoms embedded in a lattice of certain isotopes can give off heat."

Thiemens said that it might even be possible to apply the effect to enrichment of certain isotopes.

Phosphoric acid with a certain isotope of phosphorus is used for nuclear magnetic resonance.

Rocks contain certain isotopes of elements, known as natural tracers, which describe the conditions under which they formed.