Search results
Results From The WOW.Com Content Network
A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids , the conceptual anhydrides of carbonic acid , or polymers of carbon dioxide .
Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of glass, but require much higher impact-resistance. Polycarbonate lenses also protect the eye from UV light.
Drug precursors, also referred to as precursor chemicals or simply precursors, are substances used to manufacture illicit drugs. Most precursors also have legitimate commercial uses and are legally used in a wide variety of industrial processes and consumer products, such as medicines, flavourings, and fragrances.
Polycarbonate is independently developed by Hermann Schnell at Bayer and Daniel Fox at General Electric. 1954: Polypropylene is discovered by Giulio Natta with production starting in 1957 [1] 1954: Expanded polystyrene, used for building insulation, packaging, and cups, is invented by Dow Chemical. [1] 1957
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry , the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway , such as a protein precursor .
Precursor (chemistry), a compound that participates in the chemical reaction that produces another compound; Precursor (physics), a phenomenon of wave propagation in dispersive media; Precursor in the course of a disease, a state preceding a particular stage in that course; Precursor cell (biology), a unipotent stem cell
International scientific vocabulary (ISV) comprises scientific and specialized words whose language of origin may or may not be certain, but which are in current use in several modern languages (that is, translingually, whether in naturalized, loanword, or calque forms).
The Collins COBUILD Advanced Dictionary [1] (CCAD) from HarperCollins, first published in 1987, [2] is a dictionary that distinguished itself by providing definitions in full sentences, rather than excerpted phrases. Example sentences are given for almost every meaning of every word, drawn from a large corpus of actual usage.