ВЛИЯНИЕ МЕХАНОАКТИВАЦИИ ОКСИДОВ РЗЭ НА УДЕЛЬНУЮ ЭЛЕКТРОПРОВОДНОСТЬ БОРАТНЫХ РАСПЛАВОВ

The effect of mechanical activation of M2O3 (La2O3, Ce2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Yb2O3, Lu2O3) oxides on the electrical conductivity (æ) of the B2O3–M2O3 molten systems has been studied. It is supposed that protons can be the major current carriers in the melts, which enters the melt because of B2O3 hydration. The æ value change of borate melts for various M2O3 content is explained by the corresponding structure variation of the structural units as a result of dissociation of boron-oxygen groups consisting of OH groups. When temperature grows, the activation energy of electrical conductivity in the B2O3–M2O3 melts increases due to decomposition of superstructural units: [B3O4,5] and B3O3O3/2OH. The dependence of æ value against the serial number of lanthanide in series of B2O3–La2O3 → B2O3–Lu2O3 melts have been found to be subject to the intranuclear periodic sequence, which depends on the stabilization energy of the basic terms of rare earth ions.Изучено влияние механоактивации оксидов M2O3 (La2O3, Ce2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Yb2O3, Lu2O3) на удельную электрическую проводимость (æ) расплавленных систем B2O3–M2O3. Предположено, что основными носителями тока в этих расплавах могут быть протоны, которые попадают в расплавы вследствие гидратации B2O3. Изменение величины æ боратных расплавов для разных содержаний M2O3 объясняется соответствующим изменением строения структурных единиц в результате диссоциации борокислородных групп, в состав которых входят группы OH. С повышением температуры энергия активации удельной электропроводности в расплавах B2O3–M2O3 увеличивается вследствие распада надструктурных единиц: [B3O4,5] и B3O3O3/2OH. Найдена зависимость величины æ от порядкового номера лантаноида, которая в ряду расплавов B2O3–La2O3 → B2O3–Lu2O3 подчиняется внутрирядной периодичности, зависящей от энергии стабилизации основных термов ионов редкоземельных элементов (РЗЭ)

Population Exposure Dose Reconstruction for the Urals Region

This presentation describes the first preliminary results of an ongoing joint Russian-US pilot feasibility study. Many people participated in workshops to determine what Russian and United States scientists could do together in the area of dose reconstruction in the Urals population. Most of the results presented here came from a joint work shop in St. Petersburg, Russia (11-13 July 1995). The Russians at the workshop represented the Urals Research Center for Radiation Medicine (URCRM), the Mayak Industrial Association, and Branch One of the Moscow Biophysics Institute. The US Collaborators were Dr. Anspaugh of LLNL, Dr. Nippier of PNL, and Dr. Bouville of the National Cancer Institute. The objective of the first year of collaboration was to look at the source term and levels of radiation contamination, the historical data available, and the results of previous work carried out by Russian scientists, and to determine a conceptual model for dose reconstruction

Extended defects in natural diamonds: Atomic Force Microscopy investigation

Surfaces of natural diamonds etched in high-pressure experiments in H2O, CO2 and H2O-NaCl fluids were investigated using Atomic Force Microscopy. Partial dissolution of the crystals produced several types of surface features including the well-known trigons and hillocks and revealed several new types of defects. Besides well-known trigons and dissolution hillocks several new types of defects are observed. The most remarkable ones are assigned to anelastic twins of several types. The observation of abundant microtwins, ordering of hillocks and presence of defects presumably related to knots of branched dislocations suggests importance of post-growth deformation events on formation of diamond microstructure. This work confirms previous reports of ordering of extended defects in some deformed diamonds. In addition, the current work shows that natural diamonds deform not only by dislocation mechanism and slip, but also but mechanical twinning. The dominant mechanism should depend on pressure-temperature-stress conditions during diamond transport from the formation domain to the Earth surface.Comment: Submitted to special issue (1st European Mineralogical congress, Frankfurt, Germany, September 2012) of European Journal of Mineralogy. 21 page, 9 figure