Complex defects in crystal scintillation materials and phosphors

The possibility of the existence of complex defects in pure and doped crystal phosphor discussed in work. The luminescent properties of mono- and nanocrystals of zinc tungstate, the powders of YAG with various compositions are studied. It is shown that the intrinsic defects, impurities, oxygen vacancies, the hydroxyl groups may be present in the structure of the complex defects (nanodefects). Nanodefects form during synthesis and have high efficiency of the transfer of excitation energy to the emission centres

Complex defects in crystal scintillation materials and phosphors

The possibility of the existence of complex defects in pure and doped crystal phosphor discussed in work. The luminescent properties of mono- and nanocrystals of zinc tungstate, the powders of YAG with various compositions are studied. It is shown that the intrinsic defects, impurities, oxygen vacancies, the hydroxyl groups may be present in the structure of the complex defects (nanodefects). Nanodefects form during synthesis and have high efficiency of the transfer of excitation energy to the emission centres

Nanodefect substructures in crystal phosphors

We investigated spectral and kinetic characteristics of the luminescence in alkali halide crystals with polyvalent impurities, crystal phosphors based on metal tungstates in the form of nano-, micro- and bulk crystals. The possibility of the existence of complex defects (nanodefects) in materials containing high defect concentration is shown

Kinetic parameters of the uranium luminescence in Lif crystals

The results of researches with nanosecond time resolution of kinetic characteristics of luminescence buildup and decay in crystals LiF(U)-O at 300 K under action of both laser pulse with energy 3,68 eV and electron pulse with energy 300 keV have been presented. Influence of excite method on kinetic characteristics of uranium luminescence buildup and influence of uranium on kinetic characteristics of oxygen luminescence in crystal were establishe

Thermal stability of color centers in LiF crystals: dependence on radiation type and dose

Accumulation of radiation defects at irradiation is the complex result of consecutive and mutually independent events: formation of primary pair, spatial separation of its components and their transformation into stable ones under experimental conditions [1]..

Strategic litigation against torture: Why domestic courts matter

Strategic human rights litigation is often associated with filing cases before international courts and treaty bodies. While international litigation is an important avenue of seeking social change and setting new standards of rights protection, it has its limitations and needs to be combined with domestic litigation to maximize the impact of legal action for seeking accountability and reparations for torture. This article argues that significant advances in protecting the rights of victims of torture and similar crimes can be achieved through domestic courts even in countries with limited respect for the rule of law. This article is not a review of global practice, it is based on lessons and reflections from personal experience of over 25 years of strategic litigation and advocacy against torture; learnings from the work of partner organizations and lawyers from around the world, as well as the study on the impacts of strategic litigation on torture in custody published by the Open Society Justice Initiative. The article discusses selected examples of strategic human rights litigation against torture before domestic courts in different countries. It argues that domestic courts can be better placed than their international counterparts to address some of the elements of protection of victims’ rights. It does not cover universal jurisdiction cases but rather focuses on how domestic courts can be used to address torture that takes place in the same country. It concludes with lessons learned from these experiences

Archival Analysis of Slash-And-Burn Agriculture in the Northern Ural Mountains at the End of the Nineteenth Century

AbstractAt the end of the nineteenth century, the northern territories of the Russian Plain and western piedmont of Northern Ural Mountains were under various land-use systems, including slash-and-burn (SAB) agriculture. Using archival materials for the years 1880–1910 as data sources, we analyse the the location and extent of SAB agriculture, it timing, and its impact on the landscapes at the turn of the nineteenth and twentieth centuries, and present a review of the historical and ethnographic literature. The study area is in the western piedmont of the Northern Ural Mountains, between the Kama and Pechora rivers in dark conifer dominated forests. The population is sparse (14 people per 100 km² in 1900) and settled along the rivers. In 1885 the practice of SAB agriculture was totally prohibited, but the unusually large crop harvest during the first years of the ban led people to risk breaking the law. Between the years 1885 and 1894 a total number of 175 SAB cases was recorded in the study area. The SAB sites were used only once before being abandoned. The recorded plots were usually cultivated by one family. They small (0.03 ha to 2.70 ha, with a median of 0.55 ha) and located within 7.5 km of the settlements. The practice SAB agriculture led to the formation of mosaics of multiple-aged pyrogenic forest associations near the settlements.Abstract At the end of the nineteenth century, the northern territories of the Russian Plain and western piedmont of Northern Ural Mountains were under various land-use systems, including slash-and-burn (SAB) agriculture. Using archival materials for the years 1880–1910 as data sources, we analyse the the location and extent of SAB agriculture, it timing, and its impact on the landscapes at the turn of the nineteenth and twentieth centuries, and present a review of the historical and ethnographic literature. The study area is in the western piedmont of the Northern Ural Mountains, between the Kama and Pechora rivers in dark conifer dominated forests. The population is sparse (14 people per 100 km² in 1900) and settled along the rivers. In 1885 the practice of SAB agriculture was totally prohibited, but the unusually large crop harvest during the first years of the ban led people to risk breaking the law. Between the years 1885 and 1894 a total number of 175 SAB cases was recorded in the study area. The SAB sites were used only once before being abandoned. The recorded plots were usually cultivated by one family. They small (0.03 ha to 2.70 ha, with a median of 0.55 ha) and located within 7.5 km of the settlements. The practice SAB agriculture led to the formation of mosaics of multiple-aged pyrogenic forest associations near the settlements

Churn Prediction Task in MOOC

Churn prediction is a common task for machine learning applications in business. In this paper, this task is adapted for solving problem of low efficiency of massive open online courses (only 5% of all the students finish their course). The approach is presented on course “Methods and algorithms of the graph theory” held on national platform of online education in Russia. This paper includes all the steps to build an intelligent system to predict students who are active during the course, but not likely to finish it. The first part consists of constructing the right sample for prediction, EDA and choosing the most appropriate week of the course to make predictions on. The second part is about choosing the right metric and building models. Also, approach with using ensembles like stacking is proposed to increase the accuracy of predictions. As a result, a general approach to build a churn prediction model for online course is reviewed. This approach can be used for making the process of online education adaptive and intelligent for a separate student