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1.
D. G. Belov Yu. A. Ol'khov G. P. Belov T. I. Solovyeva G. I. Kozub 《Journal of Thermal Analysis and Calorimetry》1996,46(1):237-243
Polyacetylene films irradiated by-rays up to 100 MRad were studied by means of TMA, DTG and DSC methods.It is shown that as the irradiation dose increases the concentration of topological branching knots into the polymer chains and theT
g values decrease, the total mass loss and the enthalpy of the thermal isomerization reaction also decrease. 相似文献
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Theoretical and experimental studies of the conductivity and magnetoresistance of selectively doped structures of GaAs/AlGaAs quantum well structures near a metal-insulator phase transition have been reviewed. Special attention is focused on the role of the structure of impurity bands, which are narrow in the absence of intentional compensation and, in the case of doping of barriers, include the partially filled upper Hubbard band. It has been shown that the indicated structures exhibit (i) specific mixed conductivity, which can, in particular, include the contribution from delocalized states in the impurity band; (ii) the virtual Anderson transition, which is suppressed with an increase in disorder owing to compensation or with an increase in the concentration of a dopant; (iii) slow relaxations of the hopping magnetoresistance caused by the Coulomb glass effects, including, in particular, the states of the upper Hubbard band; and (iv) the suppression of the negative interference magnetoresistance owing to the spin effects. 相似文献
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Suppression of the virtual anderson transition in the impurity band of doped quantum well structures
We have previously observed activation-type conductivity with low activation energies of heavily doped p-GaAs/AlGaAs quantum well structures at low temperatures. It has been attributed to the delocalization of the electron states
near the maximum of a narrow impurity band in the sense of the Anderson transition. The possibility of this delocalization
at a relatively low impurity concentration is associated with the narrowness of the impurity band in the presence of weak
disorder. In this case, charge carriers were activated from the tail of the band and their presence was due to the background
(weak) compensation. In this work, we study the dependence of the above virtual Anderson transition on the external compensation
and impurity concentration. It has been found that an increase in the compensation does not initially affect the Anderson
transition; however, at a higher compensation, it leads to the suppression of the transition owing to the growing disorder.
An increase in the impurity concentration also initially leads to the suppression of the Anderson transition due to the disorder
associated with the partial overlap of the Hubbard bands. However, the conductivity becomes metallic at a fairly high concentration
due to the Mott transition. 相似文献
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Fedorov B. S. Fadeev M. A. Kozub G. I. Chekhlov A. N. Konovalova N. P. Sashenkova T. E. Berseneva E. N. Dobrokhotova O. V. Tatyanenko L. V. 《Russian Chemical Bulletin》2011,60(6):1181-1184
Complexes of platinum tetrachloride with substituted nicotinamides and isonicotinamides were synthesized by the reactions
of the corresponding amides with hexachloroplatinic acid. All these complexes are low-toxic. The strong antimetastatic activity
of these complexes against Lewis lung carcinoma and B16 melanoma experimental tumors was found in an enzyme system and was
then shown in experiments on animals. 相似文献
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