Бимолекулярная рекомбинация носителей заряда в молекулярно допированном поликарбонате
Abstract—The general problems of the bimolecular recombination of charge carriers in molecularly doped polycarbonate are discussed. Experimental studies are performed via the transient radiationinduced conductivity method. Transientcurrent curves are numerically calculated via the multiple trapping model. The calculated and experimental curves are in good agreement. It is shown that the studied molecularly doped polymer undergoes bimolecular recombination via the Langevin mechanism.
The dipolar disorder formalism (DDF) of Borsenberger and Bдssler has been further developed based on a unified approach treating the van der Waals and the dipolar disorder energies as being roportional to mean intersite distance in a certain power. Tested against real molecularly doped polymers with the concentration of the dopant changing in a wide range, this approach gives values of the exponent lying in the interval from _1.5 to _2.5. The total disorder is represented by an algebraic combination of four material parameters relating to the dopant and the polymer matrix weighted by their relative weight concentrations. What is important, we seem to get able to explain the near constancy of the total disorder when the concentration of the polar dopant changes. Until recently, this unusual behavior of the total disorder defied any reasonable explanation.
The effect of preliminary electron beam irradiation on hole transport in a molecularly doped polymer was studied with the use of the time of flight technique in the radiation_induced mode. Specimens that exhibit a plateau on their time of flight curves were selected for the study, since they suggest the occurrence of quasi equilibrium transport in the system according to the conventional point of view. In the extremely small signal mode, current transients in the case of bulk irradiation have a form corresponding to dispersive, rather than Gaussian, transport, although hole movement is observed in the presence of charged sites (trapped electrons). On passing to the moderately large signal mode (preirradiation to a dose of up to 5 Gy), the current transients undergo noticeable changes, which might be mistakenly interpreted as evidence for the influence of charged sites on hole transport in accordance with the predictions of the dipolar glass theory. In actuality, these changes are due to the effect of a space charge field and the hole mobility remains almost unchanged in this case. The appearance of the plateau on the current transients is an artifact of the procedure, and the hole transport is dispersive.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.