Glass absolute index

Quantitative determination of the absolute distance from the surface to a labeled cell membrane at a cell/substrate contact region can be based on the variation of F(d) with 0.(1O6) This effort is challenging because corrections have to be made for 0-dependent reflection and transmission through four stratified layers (glass, culture medium, membrane, and cytoplasm), all with different refractive indices. For 3T3 cells, Lanni et a//1065 derived a plasma membrane/substrate spacing of 49 nm for focal contacts and 69 nm for close contacts elsewhere. They were also able to calculate an approximate refractive index for the cytoplasm of 1.358 to 1.374. 

Because there is no absolute standard for gloss, existing standards (usually optically flat black glass plates) are assigned values that depend on the refractive index of the glass employed and that may vary from one test to another. 

Ono s method of cement kiln evaluation is based on observations of clinker or cement powder mounted in a liquid medium on a glass microscope slide. A polar ized-light microscope (the so called petrographic microscope) is an absolute necessity, and magniflca tions at approximately 400X are recommended. To determine the parameters of the kiln conditions in Ono s method as described in 1995, cement or clinker powder is sieved through a 100 pm screen (approxl mately U.S. Sieve No. 140), and a powder mount is prepared with a liquid of refractive index in the range of 1.705 to 1.715. The principal value of Ono s tech nique is that it can be employed by a competent, well trained microscopist on a small sample of clinker... 

Interference techniques are sometimes used to measure glass homogeneity in terms of the refractive index. While not absolute, they can measure relative refractive index differences on the order of 10 . ... 

Proceeding from that mentioned above, the authors [66] have estimated absolute values of P. variation, elucidated possible relations of this index with structural characteristics of epoxy polymers and their glass transition temperatures and also defined factors influencing the p.j. value, for four series of epoxy polymers. 

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