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Heat cleaning

Acid chlorides in pyridine convert 91 to the tetraamides 96, which, when heated, cleanly extrude 2 mol acid to give the diimidazo[4,5-h 4, 5 -e]-pyrazines (97) in good yield. The temperatures required for the pyrolysis can be readily determined by thermogravimetric analysis, and range from 285°C (97, R = Me) to 420°C (97, R = p-chlorophenyl). Under these conditions, the acid distills leaving analytically pure 97 in most cases (Scheme 35). [Pg.25]

Another important item to maintain regularly is the float valve that supplies make-up water to tanks of heated cleaning solution. Float valves are used to maintain the level in the tank so that the heating coils/elements do not become exposed. While maintaining an adequate level is extremely important, it is also important that the valve does not leak and result in dilution of the cleaner. In addition to maintenance, use of frequent analytical checks is a good way to detect slow leaks. [Pg.41]

Heat-cleaned fiberglass cloth was treated with 0.5% carboxysilane J (Table 1) and compression-molded into a laminate with nylon 6,6 polymer. Laminates were compared to state-of-the-art silane H. Table 9 shows that silane H provided a significant improvement in flexural strength over the control, expecially after a 2 h water boil, but a carboxysilane/zinc ion ionomer system gave an even better strength improvement. [Pg.114]

Six layers heat-cleaned fiberglass, 0.5% silane nylon 6,6. "Carboxysilane, 0.25 Zn per free carboxy. [Pg.115]

Some as-coated slides were conditioned in deionized water at 50°C for 24 h and at 100°C for 4 h. For a control, an as-polished slide was heat-cleaned at 250°C immediately prior to analysis by TOF SIMS and XPS, respectively. Control specimens were also treated similarly with deionized water. In fact, the deionized water-washed slide was checked by SIMS prior to coating with APS. [Pg.346]

Heat-cleaned E-glass slide surface. Table 1 shows that the heat-cleaned glass surface is confirmed to be silica-rich because of higher Si and O surface concentrations compared to the bulk analysis obtained by inductively coupled plasma (ICP). This is accommodated by a lower surface calcium concentration. The SIMS results given below demonstrate that a significant proportion of the oxygen is probably present as silanol. [Pg.347]

Coated E-glass slide surface. (A) Positive ions. As shown in Fig. 3 and Table 3, the major components on the heat-cleaned surface are Si (m/z = 28), A1 (m/z = 27), and Ca (m/z = 40). However, from Table 4 it can be seen that the aluminium surface concentration after treatment with HAPS was still very intense and increased after extraction with warm and hot water. These results are consistent with the XPS results shown in Figs 1 and 2, and are further indicative of aluminium becoming an integral part of the surface coating. Moreover, for the HAPS deposited from deionized water onto silver foil (99.99%), the peak at... [Pg.349]

Figure 3. The positive ion TOF SIMS spectra for the deionized water-washed E-glass slides after heat cleaning at 250°C. Figure 3. The positive ion TOF SIMS spectra for the deionized water-washed E-glass slides after heat cleaning at 250°C.
The positive ions from the heat-cleaned E-glass slide surface... [Pg.350]

Surface Heat-cleaned Coated Warm-water extracted Hot-water extracted... [Pg.351]

The cleavage plane of silicon is 111 and a cleaved surface formed under UHV conditions is reconstructed in a 2 x 1 surface lattice. Above 750 K, this converts irreversibly to a 7 x 7 structure, which is the same as that produced if a clean surface is generated by ion bombardment and annealing or by simple heat cleaning. Much of the earlier work on clean 111 silicon surfaces has been reviewed by Monch [133], but it is worth noting here that of the many reported structures for this surface, these two are now firmly believed to be intrinsic, and not impurity stabilized. [Pg.210]


See other pages where Heat cleaning is mentioned: [Pg.404]    [Pg.136]    [Pg.73]    [Pg.829]    [Pg.112]    [Pg.39]    [Pg.43]    [Pg.106]    [Pg.183]    [Pg.346]    [Pg.351]    [Pg.353]    [Pg.46]    [Pg.130]    [Pg.428]    [Pg.118]    [Pg.471]    [Pg.404]    [Pg.89]    [Pg.141]    [Pg.73]    [Pg.636]    [Pg.294]    [Pg.829]    [Pg.282]    [Pg.66]    [Pg.404]    [Pg.73]    [Pg.292]    [Pg.307]    [Pg.49]    [Pg.273]    [Pg.274]    [Pg.43]    [Pg.212]    [Pg.135]    [Pg.505]   
See also in sourсe #XX -- [ Pg.249 ]




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Applications heat cleaning

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Heating surfaces continuously cleaning

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