摘要:

The production of damage in aSilattice by internally starting 100 eV self-recoils has been studied using a MD simulation. Different initial lattice temperatures below the Debye temperature forSihave been considered. The number of stable atomic displacements and the amount of atomic mixing increase with the initial target temperature. The increase with temperature of atomic mixing is nonlinear -appreciable changes take place between 300 and 500 K, while the difference between the amount of mixing corresponding to 0 and 300 K is negligibly small.

ISSN:1042-0150    

DOI:10.1080/10420159508223989

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Carbonaceous clusters-supposed to be the carriers of electric conductivity-are formed along latent tracks of energetic ions in polymers. The different experimental techniques for cluster determination are summarized. Here we present some new results which have been derived from UV-Vis spectrometric examinations. Especially the initial phase of cluster growth is studied in detail. There are hints that a threshold energy density has to be deposited in the polymer before cluster growth sets in. This threshold is similar to the one for producing radicals (as seen by EPR studies), and to the one for the onset of strong polymeric conductivity. The cluster growth is shown to scale rather well with the mean transferred electronic energy density. The increase in cluster growth with energy density is much slower than the one of radical formation and conductivity.

ISSN:1042-0150    

DOI:10.1080/10420159508223990

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A stack of seven 15 μ thick polyvinlyl alcohol (PVA) foils was irradiated with 16 MeV electrons. In order to allow for the electrons’ slowing-down until stopping, six 5 mm thick Al plates had been inserted in between these PVA foils. The fractional depth distribution of the PVA destruction is derived from the change in the UV-Vis optical spectrum of PVA with depth.

ISSN:1042-0150    

DOI:10.1080/10420159508223991

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The results of EPR and optical absorption spectral studies on linarite are reported here. The observed absorption bands in the optical spectrum at 12050, 16660 and 21730 cm−1indicate the presence of Cu(II) ion in tetragonaily distorted octahedral site symmetry (4-D4h). The parameters evaluated from the optical spectrum are Dq = 1205, Ds = 3763 and Dt = 1335 cm−1which confirm the square field coordination for Cu(II) in the complex. By correlating EPR and optical data, the orbital reduction factors K∥and K⊥are calculated as 0.6554 and 0.8730 respectively, and the covalency parameters are also calculated, in order to predict the nature of in-plane [sgrave]-bonding and π-bonding. The infrared spectrum of linarite confirms the presence of water and sulphate ions in the complex.

ISSN:1042-0150    

DOI:10.1080/10420159508223992

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The optical absorption is studied as a function of γ-irradiation dose and composition for a series of magnesium phosphate glasses. The optical absorption spectra were measured in the wavelength range from 200 to 1100 nm at different γ-doses in the range from 0.2 to 1.0 Mard. The obtained results are analysed assuming optical absorption by indirect transitions. Values of Λ0the absorption band edge wavelength, the optical energy gap and the width of the band tail (Eopt, and ΔE) are determined. They are found to be γ-irradiation dependent for γ-dose values up to 1.0 Mard. It was found from these parameters that the present glass system can be divided into two distinct compositional regions: below and above 35 mole % MgO.

ISSN:1042-0150    

DOI:10.1080/10420159508223993

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A theoretical approach to the self-organization phenomena in irradiated crystals, which contain traps for vacancies and interstitials, is developed. In considered system two kinds of dissipative structure can arise.

ISSN:1042-0150    

DOI:10.1080/10420159508223994

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor