The tactic of occupation has passed its half-life, leaving the Occupation to scramble for new footing this spring.
The half-life of a piece of technology these days is very short.
But the half-life of a piece of hardware is very short these days.
The latter has a half-life of only 8.8 minutes and so counting must begin soon after the irradiation.
The half-life must find its mate or, after a few brief days, it dies, leaving its line extinct.
It is a suppression of the great lower centers, and a living a sort of half-life, almost entirely from the upper centers.
And, finally, Moglaut had warned that the compact power unit pocketed on the left breast had a half-life of only thirteen years.
By taking such an attitude to the past we should only fall into the half-will and half-life common to an age of decadence.
He had been working on a way to inhibit radioactivity—speed up the half-life until they had taken the grant away.
Now the old problem of half-life is taking its toll, and we cant even hope to keep up with the birth rate any more.
also halflife, half life, 1864, with meaning "unsatisfactory way of living;" the sense in physics, "amount of time it takes half a given amount of radioactivity to decay" is first attested 1907.
The time required for half the nuclei of a specific radionuclide or radioactive substance to undergo radioactive decay. Also called physical half-life.
The time required for half the quantity of a drug or other substance deposited in a living organism to be metabolized or eliminated by normal biological processes. Also called biological half-life.
The time required for the radioactivity of material taken in by or administered to an organism to be reduced to half its initial value by a combination of biological elimination processes and radioactive decay. Also called effective half-life.
The average time needed for half the nuclei in a sample of a radioactive substance to undergo radioactive decay. The half-life of a substance does not equal half of its full duration of radioactivity. For example, if one starts with 100 grams of radium 229, whose half-life is 4 minutes, then after 4 minutes only 50 grams of radium will be left in the sample, after 8 minutes 25 grams will be left, after 12 minutes 12.5 grams will be left, and so on.
In physics, a fixed time required for half the radioactive nuclei in a substance to decay. Half-lives of radioactive substances can range from fractions of a second to billions of years, and they are always the same for a given nucleus, regardless of temperature or other conditions. If an object contains a pound of a radioactive substance with a half-life of fifty years, at the end of that time there will be half a pound of the radioactive substance left undecayed in the object. After another fifty years, a quarter-pound will be left undecayed, and so on.
Note: Scientists can estimate the age of an object, such as a rock, by carefully measuring the amounts of decayed and undecayed nuclei in the object. Comparing that to the half-life of the nuclei tells when they started to decay and, therefore, how old the object is. (See radioactive dating.)