Sunday, September 21, 2008

Lithium

Lithium (pronounced lɪe-thi-um) is a chemical element with the symbol Li and atomic number 3. It is a soft alkali metal with a silver-white color. Under standard conditions, it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly reactive, corroding quickly in moist air to form a black tarnish. For this reason, lithium metal is typically stored under the cover of oil.

According to theory, lithium (mostly 7Li) was one of the few elements synthesized in the Big Bang, although its quantity has vastly decreased. The reasons for its disappearance and the processes by which new lithium is created continue to be important matters of study in astronomy. Lithium is the 33rd most abundant element on Earth, but due to its high reactivity only appears naturally in the form of compounds. Lithium occurs in a number of pegmatitic minerals, but is also commonly obtained from brines and clays; on a commercial scale, lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride.

Trace amounts of lithium are present in the oceans and in some organisms, though the element serves no apparent biological function in humans. Nevertheless, the neurological effect of the lithium ion Li+ makes some lithium salts useful as a class of mood stabilizing drugs. Lithium and its compounds have several other commercial applications, including heat-resistant glass and ceramics, high strength-to-weight alloys used in aircraft, and lithium batteries. Lithium also has important links to nuclear physics: the splitting of lithium atoms was the first man-made form of a nuclear reaction, and lithium deuteride serves as the fusion fuel in staged thermonuclear weapons.

Also See: http://education.jlab.org

Monday, September 08, 2008

Cheap Mobile Phones

Acquiring a cheap mobile phone is every one's wish but only the smart ones manage to grab one. You need to be on the look out for one before you actually buy it. When it comes to buying mobile phones users have two options: either to buy a brand new one from the grey market or buy a used mobile phone from a reseller. Quite often users prefer the first option as a first hand piece has a certain novelty to it, which a used piece does not. The grey market manages to ship in knock off pieces of original phones and sell them in the grey market at throwaway prices. Inspite of selling these phones at a deep discount sellers still manage to make a small profit out of such sales .However users should not expect warranty and after sales service for these phones as these phones are being sold at heavily discount prices. The axiom 'You gain some. You lose some' holds true in such circumstances. Buying mobile phones from online resellers is also an interesting option, which users have. However, the prices of these mobile phones will be slightly higher than the smuggled pieces mentioned before. Online stores do provide a replacement warranty for their customers and it comes at a price. However, the online option is still a better method as compared to the grey market one. Buying used or second-hand phones from a reseller is a good option when you are purchasing feature rich high-end phones. These high-end phones come with multiple functionalities and require a little bit of after sales service like anti –virus installation etc. Resellers in order to boost their brand equity often provide good after sales service for these phones. At choosecellphones you can get array range of cell phones like: Samsung cell phone, LG cell phones, Motorola cell phones, Nokia cell phones. Beside of this we are offering
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