Beam-irradiated material

Conduction Heat Transfer in Beam-Irradiated Materials... 

Comparing the spectra in the right panel, which characterize the molecular tilt angle, one finds the same polarization dependence for the two ion beam irradiated materials, which is opposite to the one of the rubbed polyimide film. Hence, a downwards liquid crystal pretilt angle is expected for both ion beam treated surfaces. Again, since the overall shape and the tt intensities and their dichroism is comparable for the two ion beam irradiated films, liquid crystals ai e expected to exhibit a technologically sufficient pretilt angle on an ion beam irradiated amorphous carbon layer. 

H. NabU, H. Ismail, Enhancing the thermal stability of natural rabber/recycled ethylene-propylene-diene mbbo" blends by means of introducing pre-vulcanised ethylene-propylene-diene mbber and electron beam irradiation. Materials Design, ISSN 0261-3069 56 (April 2014) 1057-1067. http //dx.doi.Org/10.1016/j.matdes.2013.12.020. 

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. 

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. 

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). 

Ion Beams. Several investigations have been made on the effects of ion beam irradiation on simple chemical systems. Polymers have also been irradiated with ion beams as an extension of studies on the ion implantation of other materials. To date, most of these studies have been concerned with gross effects, sometimes through to carbonisation (70) but here is a field which could have an industrial potential. 

The increase in the modulus for Bis A PSF and Hq/Bp PSF with irradiation indicated that crosslinking predominated for both polymers and that the crosslink structures were probably basically similar. Hq/Bp(50) PSF was considerably more radiation resistant than Bis-A PSF, as shown by the rate of decrease in the elongation at failure. For both polymers, there was an initial rapid decrease in the elongation at failure followed by a slower decrease. This effect was also demonstrated by the variation in the fracture toughness (KI(.) with irradiation for Bis-A PSF. This work with cobalt-60 gamma radiation complements earlier studies of these materials using high dose rate electron beam irradiation (6). 

Figure 7 Schematic drawing of the damage in reactor materials induced by neutrons, and its simulation by the triple-ion-beam irradiation.

Using the triple-ion beam irradiation apparatus, the microstructural evolution of austenitic stainless steel, which is considered as a structural material for water-cooled fusion reactors... 

The ultimate resolution capability of the terpolymers was determined by electron beam irradiation (20kv, 5X10 C/cm ). Figure 4a depicts O.Siim and l/im lines and spaces printed in P(M-OM-CN) (69 16 15). Optical contact printing exposures (200-400 nm) are illustrated by Figure 4b which shows 0.75fim lines and spaces, and Figure 4c which depicts profiles of Ijim lines and spaces. These results are typical of all the materials examined. 

Plastics are by far the largest group of polymeric materials being processed by electron beam irradiation. Cross-linking of polyolefins, PVC, polyesters, polyurethanes, fluoropolymers, and fiber-reinforced composites is a common practice. 

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