摘要:

Pour un polymère, d'une nature chimique dèfinie, il est intéressant d'étudier comment un paramètre physique comme la cristallinité, intervient sur les caractéristiques des traces révélées.

ISSN:0033-7579    

DOI:10.1080/00337577708237449

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Radiation-chemical alkylation of C2−C4defines with adamantane was studied in gas phase at temperatures 270–430°C. The main reaction product is monoalkyladamantane. The reaction proceeds by a free radical chain mechanism. The effective activation energy is of the order of 8 to 10 k cal/mole. Thermal alkylation was carried out for comparison and the contribution of the thermal component to the radiation-thermal process was estimated. Liquid phase alkylation of hexafluoropropylene with adamantane was studied in the presence of solvents. Under various conditions mono-and di-substituted adamantanes are produced containing fluorine in end groups. These compounds were converted to corresponding fluoroalkenyladamantanes by dehydrofluorination. The kinetic parameters were calculated and physical-chemical data concerning some of the resulting products were determined.

ISSN:0033-7579    

DOI:10.1080/00337577708237450

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A new model based on experimental observation is developed for the build-up of disordered material in ion bombarded silicon. The model assumes that disordered zones are created in a background of migrating point defects, these zones then act as neutral sinks for such defects which interact with the zones and cause recrystallization. A simple steady state rate theory is developed to describe the build-up of disordered material with ion dose as a function of temperature. In general the theory predicts two distinct behaviour patterns depending on the temperature and the ion mass, namely a linear build-up with dose to complete disorder for heavy bombarding ions and a build-up to saturation at a relatively low level for light ions such as protons. However, in some special circumstances a transition region is predicted where the build-up of disorder approximately follows a (dose)frac12;relationship before reverting to a linear behaviour at high dose.

ISSN:0033-7579    

DOI:10.1080/00337577708237451

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Measurements have been made of the SiI 2882 A line emitted from Si, SiJN4and SiC surfaces under 10keV AI+ion bombardment. The results imply that the electronic structure of the bombarded material plays a significant role in determining the intensity of the optical emission. The intensity of the above mentioned line has been used to follow the formation of SiO2, Si3N4and SiC compounds under 10 keV O2+, N2+and C+bombardments respectively. It is concluded that silicon dopant compounds can be partially formed by ion implantation. Nitride and carbide by ion implantation have been found to be more efficient than oxide formation.

ISSN:0033-7579    

DOI:10.1080/00337577708237452

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Gamma-irradiated purine and pyrimidine powders are coloured. Their absorption spectra have been determined by diffuse reflectance spectrophotometry. Plots of remission functions vs. dose are found to be identical with dose response curves obtained from ESR. Relative radiosensitivity is deduced from these plots. The absorbing species are identified with free radicals and the number of different free radicals produced from each sample can be determined.

ISSN:0033-7579    

DOI:10.1080/00337577708237453

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The effects of the glassy and polycrystalline states of methylcyclohexane (MCH), isopentane (IP), isohexane (IH) and 2,3-dimethylbutane (DMB) on the yields of the heavy products from the γ-radiolysis has been investigated. Total G values are the same in glassy and polycrystalline solids for MCH and IP, but G values for IH and DMB are larger in the polycrystalline states than those in the glassy forms. Comparison of the relative distribution of stable products always shows matrix effects. Differences in esr spectra between either states have only been observed for irradiated IH and DMB. The results from radical scavenging methods are interpreted in terms of different probabilities of radical processes in the glassy and polycrystalline states.

ISSN:0033-7579    

DOI:10.1080/00337577708237454

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Equations describing the kinetics of accumulation of radiation defects at stage-II recovery temperatures are written down within the framework of the unsaturable trap model The model takes into account interstitial capture by impurity traps, as well as the correlated and noncorrelated recombination of point defects. The suggested model makes it possible to explain the main experimental data on accumulation of radiation defects at stage-II recovery temperatures.

ISSN:0033-7579    

DOI:10.1080/00337577708237455

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Experiments carried out to etch the latent damage trails in muscovite mica and feldspar crystalline track detectors show that their etching characteristics depend upon the particular crystallographic planes. Attempts have been made to study various factors causing this anisotropy. There are indications that both,Vg(the etching velocity along the general surface) andVt(the etching velocity along the damage trail) are functions of the crystallographic planes under investigation. The results have a strong bearing in the use of crystals as charged particle detectors and in the interpretation of track analyses of lunar and meteoritic samples.

ISSN:0033-7579    

DOI:10.1080/00337577708237456

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Rutherford backscattering (RBS) and transmission electron microscopy (TEM) have been employed to investigate the annealing behaviour of Pb-implanted Si layers. The dose dependence of the post-anneal, residual disorder has been examined in considerable detail. Results indicate that the ability for the implanted Si layer to reorder as a single crystal decreases with increasing Pb concentration contained within the amorphous surface layers. The reordered Si layer is completely polycrystalline for Pb concentrations greater than a few atomic percent and the formation of this polycrystalline structure during annealing is accompanied by substantial Pb outdiffusion. Our observations lead us to suggest a step-by-step representation for Si recrystallization, where the reordered structure is dependent upon the local Pb concentration encountered as the regrowth process progresses from the bulk towards the Si suface.

ISSN:0033-7579    

DOI:10.1080/00337577708237457

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The γ irradiation of organic solutions of Cholesteric Liquid Crystals (CLC) leads to a decrease in the temperature at which CLC films made from these solutions change colours compared to films prepared from the unirradiated solutions. The decrease in the color transition temperature was found to be proportional to the absorbed dose. The proportionality coefficient can be varied by changing the solvent and the concentration of the solute thus making this system suitable for dosimetry over a large range (tens of Krads to tens of Mrads).

ISSN:0033-7579    

DOI:10.1080/00337577708237458

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor