Ionizing radiation characteristic

Polyimide. Polyimide is a biaxiaHy oriented high performance film that is tough, flexible, and temperature- and combustion-resistant. Its room temperature properties compare to poly(ethylene terephthalate), but it retains these good characteristics at temperatures above 400°C. Its electrical resistance is good and it is dimensionally stable. The principal detriment is fairly high moisture absorbance. The main uses are for electrical insulation, particularly where high temperatures are prevalent or ionizing radiation is a problem. The films may be coated to reduce water absorption and enhance... 

Smirnova and coworkers studied the influence of various types of ionizing radiations on the physiomechanical characteristics of a statistical polymer of butadiene and acrylonitrile137. Although the polymer is a statistical polymer, the nature of its thermo-mechanical curve indicates a block nature of the polymeric basis of the rubber there is a... 

Ionizing radiation is divided into alpha and beta particles and gamma rays. Each has its unique characteristics, which require different safety approaches. In general, the more radiation exposure a person receives, the greater the likelihood of cancer. 

There is sometimes a question as to whether a particular initiator or initiator system initiates polymerization by radical, cationic, or anionic means. Such a question can easily arise, for example, in polymerizations initiated by ionizing radiation. The mode of initiation of a particular initiator can be distinguished by a consideration of its characteristics compared to those of known radical, cationic, and anionic initiators ... 

Radiation-induced genomic instability and bystander effects are now well-established consequences of exposure of living cells to ionizing radiation. Cells not directly traversed by radiation may still exhibit radiation effects. This phenomenon, known as bystander effect, has become a major activity in radiation biology and in some cases has challenged the conventional wisdom. An example is the currently accepted models used for low-dose extrapolation of radiation risks. The currently used models assume that cells in an irradiated population respond individually rather than collectively. If bystander effects have implications for health risks estimates from exposure to ionizing radiation, then the question of whether this is a general phenomenon or solely a characteristic of a particular type of cell and the radiation under test becomes an important issue. 

Normally, TPEs are not cross-linked because the thermoplastic nature is their desired property in most cases. However, in some cases cross-linking is used to improve mechanical properties, influence flow to reduce swelling in oils and solvents, eliminate dissolution of fhe polymer in oils and solvenfs, increase heat resistance, and influence ofher performance characteristics. Examples where cross-linking by ionizing radiation is necessary for fhe given processes are ... 

Other host factors What other host factors may modify the carcinogenic response to ionizing radiation remains unclear, but it seems plain that hormonal factors, at least, play such a role in breast cancer. Immime competence and genetic characteristics, e.g., those governing DNA repair capabilities, are also possibilities. 

Rossi, H.H. (1977). The effects of small doses of ionizing radiation. Fundamental biophysical characteristics, Radiat. Res. 71,1. 

The effects of ionizing radiation on a low and a high density polyethylene and an ionomer indicate that similar networks are formed in the ionomer and in the low density polyethylene. The former crosslinks about 1.5 times as readily as the latter. In the high density resin, the network characteristics, and hence, presumably, the type and distribution of links, differ considerably from those in the other two resins. As a result, crosslinking rates in the high and low density polyethylenes cannot be directly compared. 

Self-Luminescence. The action of UV light or ionizing radiation on pure alkali-metal halide crystals causes intense luminescence particularly at low temperature. The emission spectrum is characteristic for each individual compound. This fluorescence is comparable with the recombination luminescence which occurs upon capture of an electron by a VK center (defect electron). 

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