Electron-beam irradiation

Similarly to the situation in y-irradiation, in aqueous solution the use of electron beams generates hydrated electrons and hydrogen atoms, both of which are highly active reducing agents [303-305). These species have been successfully applied to the preparation of Cu nanocolloids, especially in the presence of stabilizers such as poly(vinyl alcohol) [304] and SDBS [305], 

In contrast, in 2003 Wang et al, who previously had achieved the structural evolution of Cu(OH)2 nanobelts to Cu nanowires in a TEM instrument, showed that the process was not induced by the electron beam but rather was a multistep process that involved hydroxide thermal dehydration and two subsequent one-electron conversions, in which carbon from the supporting grids acted as the reducing agent [310], 

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For all three diallyl phthalate isomers, gelation occurs at nearly the same conversion DAP prepolymer contains fewer reactive allyl groups than the other isomeric prepolymers (36). More double bonds are lost by cyclisation in DAP polymerisation, but this does not affect gelation. The heat-distortion temperature of cross-linked DAP polymer is influenced by the initiator chosen and its concentration (37). Heat resistance is increased by electron beam irradiation. 

Foamed plastic insulation (electron-beam-irradiated plastics)... 

Silicone acrylates (Fig. 5) are again lower molecular weight base polymers that contain multiple functional groups. As in epoxy systems, the ratio of PDMS to functional material governs properties of release, anchorage, transfer, cure speed, etc. Radiation induced radical cure can be initiated with either exposure of photo initiators and sensitizers to UV light [22,46,71 ] or by electron beam irradiation of the sample. 

The influence of the gel content in polyisoprene-tackifier blends on creep resistance and peel behaviour have been recently studied [62]. The gel content was achieved by cross-linking the adhesives with electron beam irradiation. The molecular weight of the soluble fraction in the blend was always dominated by that of the initial elastomer. Creep resistance was achieved either through molecular weight increases or gel content increases. However, the peel strength is strongly... 

The large size of CPOs allows their direct observation. For this purpose, scanning tunneling microscopy (STM) is the best method [32,34]. Electron microscopic analysis is used for phthalocyanine 3 and its derivatives however, most of the porphyrin derivatives are decomposed by electron beam irradiation. Presently, although only a limited number of researchers are able to perform atomic-scale resolution measurement, this powerful analytical method is expected to be used widely in the future. The author reported a summary of STM studies on porphyrins elsewhere [34]. 

Li et al. (2000) have employed nanometer scale analysis in a FEG-TEM operating at 200 kV to distinguish between true GP zones in an Al-Zn-Mg-Cu alloy and GP zone-like defects caused by electron beam irradiation in the TEM. They studied an Al-6.58Zn-2.33Mg-2.40Cu (wt%) alloy, in which it is well known that the decomposition of supersaturated solid solutions takes place via the formation of GP zones, using conventional techniques to produce thin foil specimens of aged material. 

Negative resists generally exhibit high sensitivity but low contrast. For instp.ncin our laboratory, polymers containing thiirane groups / g v ere found to be extremely sensitive (o = 6 x 10 T C/cm2) to electron beam irradiation at a 20 kV... 

It is clear from this discussion that the dose requirement and unit cost will be lower if the material has a higher molar mass M and the reaction has a high G value. Thus, the best candidates will be a polymeric material and a chain reaction. Quite often, a free-radical irradiation is used. The radiation source of choice is usually a 60Co - y facility, although electron beam irradiation is also used. Since most radiation-chemical reactions used in industry can also be brought about by other conventional means such as thermal, or photochemical processes, the processing cost must be below 10irradiation cost one has to include the cost of operation, maintenance, and the like. (Danno, 1960). 

Thermosensitive microgel particles (Rh = 300-500 nm) were synthesised by electron beam irradiation of dilute aqueous PVME solutions [330]. It was noted that when the irradiation of the PVME solution (4.0g I, ) was... 

We believe that the luminescence at 1.0 eV is due to a structural damage induced by ion implantation rather than to a chemical doping effect, since the spectrum does not depend on the chemical species of the ion. These centers may be similar to the vacancies induced by 3-MeV electron-beam irradiation, as reported by Troxell and Watkins (1979), who find donorlike and acceptorlike levels —0.1 eV from the band edges. 

Electron beam inks, 14 314-315 Electron beam irradiation, silicone network preparation via, 22 567 VDC polymer degradation via, 25 713 Electron beam lithography... 

Interest in solution inhibition resist systems is not limited to photoresist technology. Systems that are sensitive to electron-beam irradiation have also been of active interest. While conventional positive photoresists may be used for e-beam applications (31,32), they exhibit poor sensitivity and alternatives are desirable. Bowden, et al, at AT T Bell Laboratories, developed a novel, novolac-poly(2-methyl-l-pentene sulfone) (PMPS) composite resist, NPR (Figure 9) (33,34). PMPS, which acts as a dissolution inhibitor for the novolac resin, undergoes spontaneous depolymerization upon irradiation (35). Subsequent vaporization facilitates aqueous base removal of the exposed regions. Resist systems based on this chemistry have also been reported by other workers (36,37). 

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