Ion

An ion (/ˈaɪən, -ɒn/) is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. Ions can be created, by either chemical or physical means, via ionization.

In chemical terms, if a neutral atom loses one or more electrons, it has a net positive charge and is known as a cation.

If an atom gains electrons, it has a net negative charge and is known as an anion.

An ion consisting of a single atom is an atomic or monatomic ion; if it consists of two or more atoms, it is a molecular or polyatomic ion. Because of their electric charges, cations and anions attract each other and readily form ionic compounds, such as salts.

In the case of physical ionization of a medium, such as a gas, what are known as "ion pairs" are created by ion impact, and each pair consists of a free electron and a positive ion.

History of discovery

The word ion is the Greek ἰόν, ion, "going", the present participle of ἰέναι, ienai, "to go". This term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday did not know the nature of these species, but he knew that since metals dissolved into and entered a solution at one electrode, and new metal came forth from a solution at the other electrode, that some kind of substance moved through the solution in a current, conveying matter from one place to the other.

JPEG

JPEG (/ˈdʒeɪpɛɡ/ JAY-peg) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.

JPEG compression is used in a number of image file formats. JPEG/Exif is the most common image format used by digital cameras and other photographic image capture devices; along with JPEG/JFIF, it is the most common format for storing and transmitting photographic images on the World Wide Web. These format variations are often not distinguished, and are simply called JPEG.

The term "JPEG" is an abbreviation for the Joint Photographic Experts Group, which created the standard. The MIME media type for JPEG is image/jpeg, except in older Internet Explorer versions, which provides a MIME type of image/pjpeg when uploading JPEG images. JPEG files usually have a filename extension of .jpg or .jpeg.

Ion (DC Comics)

Ion is a fictional character, a DC Comics superhero. Created by writer Judd Winick and artist Dale Eaglesham for Green Lantern vol. 3 #142, Ion was devised as the new superhero identity for Green Lantern protagonist Kyle Rayner. It was later revealed to be able to form mutualism with a host, bestowing its power to a host willingly. This followed a similar retcon as Parallax, originally the new supervillain alias of Hal Jordan, which was revealed to be a parasitic embodiment of fear in the 2004–2005 miniseries Green Lantern: Rebirth.

Fictional character biography

As soon as sentient beings developed willpower, Ion was born from the green wavelength of the so-called "emotional spectrum". Its existence has been kept a secret for eons, and it resided in the Central Battery on Oa to keep Parallax, the parasitic fear entity also imprisoned there, in check, as well as granting the Guardians of the Universe, Manhunters, The Green Glob, Halla's, and then The Green Lantern Corps a portion of its vast powers. After Hal Jordan, under the influences of Parallax and Sinestro, destroyed the Central Battery, Ion, along with Parallax and Sinestro, were set free. After wandering throughout the cosmos, it eventually settled within Kyle Rayner as its host.

Tangent

In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve. More precisely, a straight line is said to be a tangent of a curve y = f (x) at a point x = c on the curve if the line passes through the point (c, f (c)) on the curve and has slope f '(c) where f ' is the derivative of f. A similar definition applies to space curves and curves in n-dimensional Euclidean space.

As it passes through the point where the tangent line and the curve meet, called the point of tangency, the tangent line is "going in the same direction" as the curve, and is thus the best straight-line approximation to the curve at that point.

Similarly, the tangent plane to a surface at a given point is the plane that "just touches" the surface at that point. The concept of a tangent is one of the most fundamental notions in differential geometry and has been extensively generalized; see Tangent space.

Time Chasers

Time Chasers (aka Tangents) is a 1994 science fiction film directed by David Giancola and starring Matthew Bruch, George Woodard, and Bonnie Pritchard. The film follows the adventures of an amateur inventor who goes through time with his female accomplice to stop an evil megacorporation intent on changing history for profit. The film was lampooned on Mystery Science Theater 3000 in 1997.

Plot

Physics teacher and amateur pilot Nick Miller (Matthew Bruch) has finally completed his quest of enabling time travel, via a Commodore 64 and his small airplane. After being inspired by a television commercial for GenCorp, he uses a ruse to bring out both a GenCorp executive and a reporter from a local paper. To Nick's surprise, the reporter is Lisa Hansen (Bonnie Pritchard), an old high school flame. One trip to 2041 later and Gencorp's executive, Matthew Paul (Peter Harrington), quickly arranges Nick a meeting with CEO J.K. Robertson (George Woodard). Impressed by the potential of time travel, Robertson offers Nick a licensing agreement on the technology.

Hackers (anthology)

Hackers (ISBN 0-441-00375-3) is an anthology of short stories edited by Jack Dann and Gardner Dozois. It contains stories by noted science fiction and cyberpunk writers of the late 1980s and early 1990s about hackers.

"Burning Chrome"

This story, written by William Gibson, was first published in Omni in July, 1982. It tells the story of two hackers who hack systems for profit. The two main characters are Bobby Quine who specializes in software and Automatic Jack whose field is hardware. A third character in the story is Rikki, a girl with whom Bobby becomes infatuated and for whom he wants to hit it big. Automatic Jack acquires a piece of Russian hacking software that is very sophisticated and hard to trace. The rest of the story unfolds with Bobby deciding to break into the system of a notorious and vicious criminal called Chrome, who handles money transfers for organized crime, and Automatic Jack reluctantly agreeing to help. The break-in is ultimately successful, but Rikki decides to leave the group and go to Hollywood, to the grief of Quine and Jack who have grown to love her.