Lens heating

Levinson, Principles of Lithography, 2nd ed., p. 162, SPIE Press, Bellingham, WA (2005). Software is often used to compensate for the effects of lens heating, see for example, P. van Oorshot, B. Kock, J. van der Spek, E. Stuiver, H. Franken, H. Bother, and R. Garreis, Performance of an I line step and scan system for suh 0.25 p,m mix and match apphcation, Proc. SPIE 3334, 423 436(1998). 

Figure 13.18 Lens heating of various optical materials as measured by OPD at i-line (365 nm), 248-nm, and 193-nm exposure wavelengths. (Adapted with permission from Ref. 131.)...

A metal cylinder A contains two small holes. Into one of these the thermometer is placed and into the other (arranged centrally) is placed the melting-point tube. The cylinder is pierced by a hori-2ontaI tunnel so the melting-point tube can be observed during heating. A lens is... 

Besides appHcation as heat-resistant molding powders for electronic and other appHcations, DAIP copolymers have been proposed for optical apphcations. Lenses of high impact resistance contain 50% DAIP, 20% benzyl methacrylate, and larger amounts of CR-39 (59). A lens of refractive index 71- = 1.569 andlow dispersion can be cast from phenyl methacrylate, DAIP, and isopropyl peroxide (60). Lenses of better impact properties can be obtained by modifying DAIP with aHyl benzoate (61). 

Copolymers of diallyl itaconate [2767-99-9] with AJ-vinylpyrrolidinone and styrene have been proposed as oxygen-permeable contact lenses (qv) (77). Reactivity ratios have been studied ia the copolymerization of diallyl tartrate (78). A lens of a high refractive iadex n- = 1.63) and a heat distortion above 280°C has been reported for diallyl 2,6-naphthalene dicarboxylate [51223-57-5] (79). Diallyl chlorendate [3232-62-0] polymerized ia the presence of di-/-butyl peroxide gives a lens with a refractive iadex of n = 1.57 (80). Hardness as high as Rockwell 150 is obtained by polymerization of triaHyl trimeUitate [2694-54-4] initiated by benzoyl peroxide (81). 

Erh., abbrev. (Erhitzung) heating, erhaben, a. raised, elevated relief convex (lens) high sublime, grand, illustrious. — erhabene Arbeit, relief, rilievo. 

Ascorbic acid is photosensitive and unstable in aqueous solution at room temperature. During storage of foods, vitamin C is inactivated by oxygen. This process is accelerated by heat and the presence of catalysts. Ascorbic acid concentration in human organs is highest in adrenal and pituitary glands, eye lens, liver, spleen, and brain. Potatoes, citrus fruits, blade currants, sea buckthorns, acerola, rose hips, and red paprika peppers are among the most valuable vitamin C sources [1,2]. 

Heat filter glass id. Secondary condensing lens system... 

Methyl radicals were produced by pyrolysis of azomethane (CH3N2CH3). Azomethane was synthesized as describe earlier [18]. It was purified periodically by fteeze-pump cycles at 77 K, and the gas purity verified by RGA. The methyl radical source was similar to that developed by Stair and coworkers. [10, 11] The source was made of a quartz tube with 3 mm OD and 1 mm ID, resistive heating was supplied by means of a 0.25 mm diameter tantalum wire wrapped outside the quartz tube. The len of the heating zone was 4 cm, recessed from the end of the tube by 1 cm. An alumina tube around the outside of the heating zone served as a radiation shield. Azomethane was admitted to the hot tube at a pressure of 1x10-8 to 1x10-7 Torr via a high-vacuum precision leak valve. The pyrolysis tube was maintained at about 1200 K, adequate to decrease the major peaks in the mass sp trum of the parent azomethane at 58 and 43 amu by at least a factor of 100. 

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