摘要:

Examined are metal-filled polymer compositions on the base of low density polyethylene (LDPE) with a differing content of magnesium (10, 20, 30 and 40%). After irradiation with gamma rays (60Co) of a well-defined dose a transition from high to low resistivity is observed for the 30 and 40% Mg composites. The radiation-induced change of specific volume resistivity permits the development of conducting polymer materials on the base of metal-filled composites with a wide range of application in engineering.

ISSN:1042-0150    

DOI:10.1080/10420159408229021

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effect of deuteron irradiation on the fatigue life of type 316 L stainless steel was studied for both in-beam and post-irradiation conditions in the high cycle fatigue (HCF) range. Torque controlled fatigue tests were performed in torsion on hour glass shaped specimens at a temperature of 400°C during and after an irradiation with 19 MeV deuterons at a beam intensity which corresponds to circa 5 × 10−6dpa/s. The data are analysed with the aid of a fatigue damage model. The analysis reveals that:

ISSN:1042-0150    

DOI:10.1080/10420159408229022

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Intersection of a moving edge dislocation with disclination configurations, an isolated wedge disclination and a quadrupole of wedge disclinations, is theoretically examined in detail. It is shown that, after a moving disclocation intersects with a disclination configuration, the force occurs which hampers the dislocation motion. By methods of the elasticity theory the exact formulae are found for the forces,F1andF2, which hamper a moving dislocation intersected with an isolated disclination and a disclination quadrupole, respectively. With the help of these formulae the flow stress of metallic glasses in an inhomogeneous deformation regime as well as the energy of elastic short-range distortions in metallic glasses are estimated within the framework of the model in which basic elements of disclination ensemble in metallic glass are isolated disclinations and disclination quadrupoles.

ISSN:1042-0150    

DOI:10.1080/10420159408229023

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The growth of second phase precipitates from the supersaturated solid solution under irradiation is investigated taking into account a new mechanism of precipitate dissolution. This mechanism is of a purely diffusion origin, i.e. it is based on diffusion outfluxes of point defects produced by irradiation within the precipitates into the host matrix, provided that the interface boundary is transparent for the point defects.

ISSN:1042-0150    

DOI:10.1080/10420159408229024

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The findings of laser excited photoconductivity response of color centers in NaCl crystals are reported here. A nitrogen laser pumped dye laser is used as the excitation source. The spectral response of the photocurrent shows a large number of distinct and resolved peaks. Of these, peaks at 450 nm and 700 nm can be unambiguously identified to F and F2centers respectively. The other peaks are assigned to two photon transition to higher excited states of F center.

ISSN:1042-0150    

DOI:10.1080/10420159408229025

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Nature of free radicals produced on γ-irradiation of polyacrylamide (PAAm) have been investigated by electron spin resonance (ESR) spectroscopy. The ESR spectrum observed for irradiated PAAm at room temperature (RT) is a triplet with hyperfine (hf) splittings of 24 G and intensity distribution of 1:3:1. Superposition of component triplet, together with a singlet originating from a different radical is found to be the best fit to the experimental spectrum at RT, as has been deduced from the total curve fitting method. The ESR spectrum of irradiated PAAm at liquid nitrogen temperature (LNT) is a sharp singlet. The spectra at RT and LNT are attributed to different interconvertible forms of the free radicals of the type ∼CH2-C(CONH2)-CH2-. A mechanism for radiative degradation of PAAm is proposed.

ISSN:1042-0150    

DOI:10.1080/10420159408229026

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The thermoluminescent (TL) glow in ZrO2film irradiated with ultraviolet radiation has been studied. The ZrO2films of thickness from 0.2 to 0.05 mm were made by mixing the ground sintered ZrO2powder with a binder in solvent then dried on a leveling flat glass plate. The sintering temperature of 1,100°C has been chosen for the demonstration of the TL results of ZrO2, pellet and film, and their crystalline structures have been investigated by the x-ray diffractometer. The TL glow curves of the ZrO2film and pellet irradiated by UV of wavelength 302 nm and exposure of 10 mJ cm−2were obtained. The results show that the TL peak positions of the ZrO2pellet shifted about 10°C from those of the film. The explanation of these differences is that for the thick sample, there is a temperature lag due to the heat conduction through the bulk of the sample during the TL readout. For the film sample, this temperature lag is negligible, so the TL glow is essentially read out simultaneously from all part of the film without the heat conduction problem. This ZrO2film can be used to calibrate the temperature peak position of the TL read out for a thick sample.

ISSN:1042-0150    

DOI:10.1080/10420159408229027

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A low energy electron beam (15 KeV) induced dimensional instability is observed in 2,4,6-Trinitrotoluene single crystals. The instability is characterised by shrinkage and relaxation whose Arrhenius plots resulted in the activation energies of the order of bond energies indicating molecular transformations which are confirmed by Laser Raman Spectroscopy recorded in the NO2symmetric stretching frequency range. The negative charge developed on the surface of the crystal by electron bombardment induces interaction with the electron deficient TNT molecules which rearrange among themselves causing crystal contraction and spiral loops on the surface.

ISSN:1042-0150    

DOI:10.1080/10420159408229028

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The optical absorption is studied as a function of γ-irradiation dose for polyvinylidene difluoride material (PVDF). Optical absorption spectra were measured in the wavelength range from 200 to 1100 nm at different γ-doses in the range from 25 to 300 Mrad. The absorption coefficient (α), absorption index (K) and the values of energy gaps (Eopt) and (ΔE) are found to be dependent on γ-doses. The increase in the degree of crystallinity of PVdF samples is due to irradiation.

ISSN:1042-0150    

DOI:10.1080/10420159408229029

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A simple mathematical model based on a system of reaction-diffusion equations makes it possible to study the influence of defect interactions on effective diffusion of implanted impurities and to determine the broadening of the impurity profiles during annealing. It is shown that special initial conditions may give rise to anomalous diffusion processes, e.g., the transient diffusion. The effective diffusion coefficient and its dependence on reaction constants is discussed under the assumption that the as-implanted profile has a δ-function or an LSS form.

ISSN:1042-0150    

DOI:10.1080/10420159408229030

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor