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The polycarbonate disc contains a spiral groove, called the " pregroove " ( because it is molded in before data are written to the disc ), to guide the laser beam upon writing and reading information.
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polycarbonate and disc
A polycarbonate disc layer has the data encoded by using bumps. B.
A standard CD-R is a thick disc made of polycarbonate with a 120 mm ( 4. 7 in ) or 80 mm ( 3. 150 in ) diameter.
The pregroove is molded into the top side of the polycarbonate disc, where the pits and lands would be molded if it were a pressed ( nonrecordable ) Red Book CD ; the bottom side, which faces the laser beam in the player or drive, is flat and smooth.
The polycarbonate disc is coated on the pregroove side with a very thin layer of organic dye.
The quality of the disc is also not only dependent on the dye used, it is also influenced by sealing, the top layer, the reflective layer, and the polycarbonate.
** Optical disc, commonly a polycarbonate disc
These discs are produced by injection molding polycarbonate into a mold cavity that has on one side a metal stamper containing a negative image of the disc data, while the other mold side is a mirrored surface.
The substrate, or basic surface on which a material adheres, is usually made of a polycarbonate plastic, but the new disc replaces this with paper.
polycarbonate and spiral
CD data is stored as a series of tiny indentations known as " pits ", encoded in a spiral track moulded into the top of the polycarbonate layer.
Traditional single layer ( SL ) writable media are produced with a spiral groove molded in the protective polycarbonate layer ( not in the data recording layer ), to lead and synchronize the speed of recording head.
polycarbonate and groove
Double-layered writable media have: a first polycarbonate layer with a ( shallow ) groove, a first data layer, a semi-reflective layer, a second ( spacer ) polycarbonate layer with another ( deep ) groove, and a second data layer.
polycarbonate and called
Other research has found that fixatives in polycarbonate plastics can cause chromosomal error in cell division called aneuploidy.
polycarbonate and because
Polish riot police squad in the 1930s, with opaque riot shield s and no helmet visors because polycarbonate was not yet invented
A chemical compatibility chart shows that polycarbonate is incompatible with ammonia and acetone because it dissolves in their presence.
polycarbonate and is
A CD is made from thick, polycarbonate plastic and weighs 15 – 20 grams.
A CD is read by focusing a 780 nm wavelength ( near infrared ) semiconductor laser through the bottom of the polycarbonate layer.
Acrylic is the most common plastic glazing used for dome skylights today ; however, polycarbonate and copolyester materials are also often used as glazing, where additional properties such as impact resistance may be required to meet specific demands.
Regarding Starck's furniture designs, he is widely known for his designs for the Italian manufacturer Kartell, many of which are made from polycarbonate plastic.
The hardtop roof is constructed of polycarbonate and manufactured by the German firm Webasto.
There is some concern about Bisphenol A ( BPA ) leakage on polycarbonate bottles due to extended dishwasher or boiling.
Roscolux is 70 % polycarbonate and 30 % deep dyed polyester.
Typical construction is from moulded polycarbonate plastic, or aluminium for more professional systems.
Clad with fiberglass fabric and polycarbonate glazing its looks as if it is made out of hanji – traditional Korean paper.
Photo filters are commonly made from glass, resin plastics similar to those used for eyeglasses ( such as CR-39 ), polyester and polycarbonate ; sometimes acetate is used.
PET is sensitive to hydrolysis and attack by strong acids, while polycarbonate depolymerizes rapidly when exposed to strong alkalis.
The main polycarbonate material is produced by the reaction of bisphenol A and phosgene.
In this way, approximately one billion kilograms of polycarbonate is produced annually.
Although it has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components.
The characteristics of polycarbonate are quite like those of polymethyl methacrylate ( PMMA, acrylic ), but polycarbonate is stronger, usable in a wider temperature range, yet more expensive.
polycarbonate and molded
The use of injection molded drinking bottles, glasses and food containers is common, but the use of BPA and other harmful chemicals in the manufacture of polycarbonate and other plastics has stirred serious controversy ( see Potential hazards in food contact applications ), leading to development and use of " BPA-free " plastics in various formulations.
Designed in 1984 by Stanford engineering lecturer Alan Adler, the Aerobie has a polycarbonate core with soft rubber bumpers molded onto the inner and outer rims.
* The Kiev 19m, which uses a molded polycarbonate body rather than the metal used in earlier models.
polycarbonate and before
Nowadays many visors are transparent, but before strong transparent substances such as polycarbonate were invented, visors were opaque like a mask with small holes to see and breathe through, such as:
Dr. Hermann Schnell of Bayer in Germany invented the polycarbonate resin in 1953, just one week before chemist Dr. Daniel Fox of GE independently made the same discovery while working on a wire coating.
polycarbonate and data
Methods for successfully sanitizing optical discs include delaminating or abrading the metallic data layer, shredding, incinerating, destructive electrical arcing ( as by exposure to microwave energy ), and submersion in a polycarbonate solvent ( e. g., acetone ).
polycarbonate and are
Some modern guitars are made of polycarbonate materials.
The first type, riot shields, are used for riot control and can be made from metal or polymers such as polycarbonate Lexan or Makrolon or boPET Mylar.
In a pioneering technique developed by Robert Fleischer, P. Buford Price, and Robert M. Walker, sheets of clear plastic, like 1 / 4 mil Lexan polycarbonate, are stacked together and exposed directly to cosmic rays in space or high altitude.
Smart cards are made of plastic, generally polyvinyl chloride, but sometimes acrylonitrile butadiene styrene or polycarbonate.
Eyeglass lenses are commonly made from plastic, including CR-39 and polycarbonate.
Safety lenses are usually made of polycarbonate.
Polycarbonate and Trivex lenses are the lightest and most shatter-resistant, making them the best for impact protection, though polycarbonate offers poor optics due to high dispersion, having a low Abbe number of 31.
They are also used to examine for chain orientation in transparent plastic products made from polystyrene or polycarbonate.
Modern gels are thin sheets of polycarbonate or polyester, placed in front of a lighting fixture in the path of the beam.
BMX riders typically use plastic pedals made of nylon, polycarbonate, or carbon reinforced plastic, although aluminum alloy, and magnesium are not uncommon pedal body materials.
Air Hockey pucks are slim discs made of Lexan polycarbonate resin.
Today there are primarily seven commodity polymers in use: polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polycarbonate, and poly ( methyl methacrylate ) ( Plexiglass ).
The thicker barriers of transparent plastic used in teller's windows and barriers in banks are also polycarbonate.
Many kinds of lenses are manufactured from polycarbonate, including automotive headlamp lenses, lighting lenses, sunglass / eyeglass lenses, swimming and SCUBA goggles, and safety glasses / goggles / visors including visors in sporting helmets / masks and police riot gear.
Windscreens in small motorized vehicles are commonly made of polycarbonate, such as for motorcycles, ATVs, golf carts, and small planes and helicopters.
Many toys and hobby items are made from polycarbonate parts, e. g. fins, gyro mounts, and flybar locks for use with radio-controlled helicopters ..
Many polycarbonate grades are used in medical applications and comply with both ISO 10993-1 and USP Class VI standards ( occasionally referred to as PC-ISO ).
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