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CR-39 plastic has an index of refraction of 1.498 and an Abbe number of 58. CR-39 is now a trade-marked product of PPG Industries. [2] An alternative use includes a purified version that is used to measure ionising radiation such as alpha particles and neutrons. Although CR-39 is a type of polycarbonate, it should not be confused with the ...
Scratch-resistant coatings are added to glasses due to scratches' extreme ability to impact a wearer's vision. Even when optical glasses are made of high scratch-resistances glass, polycarbonate, or CR-39, coatings are still used. Optical coatings include diamond-like carbon (DLC) and anti-reflective-scratch hybrid coatings. Diamond-like Carbon ...
Lenses sold in the US must pass the Food and Drug Administration ball-drop impact test, and depending on needed index these seem to currently have "best in class" Abbe vs Index ( N d): Glass (2× weight of plastics) or CR-39 (2 mm vs. 1.5 mm thickness typical on newer materials) 58 @ 1.5, Sola Spectralite (47 @ 1.53), Sola Finalite (43 @ 1.6 ...
Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of glass, but require much higher impact-resistance. Polycarbonate lenses also protect the eye from UV light.
CR-39 (CR for "Columbia Resins" and 39 denoting it as the 39th polymer) had qualities suitable for plastic lenses, making it the most noteworthy of the polymers. [6] CR-39 is commonly used in the manufacturing of plastic eyeglass lenses .
CPM S110V [39] has higher corrosion resistance than S90V and marginally better wear resistance. The additional corrosion resistance while retaining all the benefits of S90V makes this steel extremely desired for kitchen cutlery. [40] CPM S125V. It contains 3.25% carbon, 14% chromium and 12% vanadium, as well as other elements in alloy.
Low vibration resistance. Light copper color. Maximum service temperature 149 °C (intermittently 204 °C). 91.5: 2: 6.5: Cu 91.7 Ag 1.5 P 6.8: Cu–Ag–P 643/799 [23] – Silvalite. For copper, brass and bronze. Self-fluxing on copper. Also usable on silver, tungsten, and molybdenum. Primarily for copper-to-copper joining. Low resistance to ...
4.39 WEL (10 −8 Ωm) (293 K–298 K) 4.4 13 Al aluminium; use 2.45 nΩm 24.17 nΩm ... 24 Cr chromium; use 118 nΩm 125 nΩm 126 nΩm 127 nΩm 201 nΩm