Monday, April 28, 2008

Flower anatomy

Flowering plants are heterosporangiate and the pollen and ovules are formed in different organs, but these are together in a bisporangiate strobilus that is the typical flower. A flower is regarded as a modified stem with shortened internodes and behavior, at its nodes, structures that may be vastly adapted leaves. In spirit, a flower structure forms on a modified shoot or axis with an apical moisten that does not grow constantly. The stem is called a pedicel, the last part of which is the tours or container.




Adult Halloween Costumes

Tuesday, April 22, 2008

Dot matrix printer

Unlike a typewriter or daisy wheel printer, letters are tired out of a dot matrix, and thus, varied fonts and random graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies. A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, outstanding an ink-soaked cloth ribbon beside the paper, much like a typewriter.

Each dot is formed by a tiny metal rod, also called a "wire" or "pin", which uses the power of a tiny electromagnet or solenoid to drive it forward, either directly or through small levers .Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or garnet) pierced with hole to provide as guides for the pins. The moving portion of the printer is called the print head, and prints one line of text at a time.The majority dot matrix printers have a single vertical line of dot-making apparatus on their print heads; others have a few interleaved rows in order to improve dot density.

These machines can be highly durable, but eventually wear out. Ink invades the direct plate of the print head, causing grit to adhere to it; this grit slowly causes the channels in the guide plate to wear from circles into ovals or slots, providing less and less correct guidance to the printing wires. After about a million characters, even with tungsten blocks and titanium pawls, the printing becomes too unclear to read.




Adult Halloween Costumes

Wednesday, April 16, 2008

Bluetooth

Bluetooth is an industrial requirement for wireless personal area networks (PANs). Bluetooth provides a way to connect and swap information between devices such as mobile phones, laptops, PCs, printers, digital cameras, and video game consoles over a secure, globally unlicensed short-range radio frequency. The Bluetooth specifications are licensed and developed by the Bluetooth Special Interest Group.

Bluetooth is a radio standard and communications protocol mostly designed for low power consumption, with a short range based on low-cost transceiver microchips in each device. The devices use a radio communications system, so they do not have to be in line of view of each other, and can even be in other rooms, as long as the conservative transmission is powerful enough.






Adult Halloween Costumes

Thursday, April 03, 2008

Aberrations

A lens is a device for either concentrating or diverging light, usually produced from a piece of shaped glass. Lenses do not form perfect images, and there is always some degree of distortion or aberration introduced by the lens which causes the image to be an defective replica of the object. Careful design of the lens system for a exacting application ensures that the aberration is minimized. There are several different types of aberration which can influence image quality.




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