Exchange Exchange is a marketplace in which shares, options and futures on stocks, bonds, commodities, and indexes are traded. Principal U.S. stock exchanges are: New York Stock Exchange (NYSE), American Stock Exchange (AMEX), and National Association of Securities Dealers Automatic Quotation System (Nasdaq).
From Wikipedia, the free encyclopedia. The DielsâAlder reaction is an organic chemical reaction (specifically, a [4+2] cycloaddition) between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system.n a normal demand DielsâAlder reaction, the dienophile has an electron-withdrawing group in conjugation with the alkene; in an inverse-demand scenario, the dienophile is conjugated with an electron-donating group.
X-rays are a form of electromagnetic energy just light-rays and micro-waves are. X-rays have more energy than light-rays so they can penetrate and travel through materials that light-rays cannot. Film is sensitive to x-rays in the same way that it is to light-rays, so X-rays can be used produce images. X-rays that are sent through an object can produce an image on a piece of film placed on the opposite side of the object.