Picosecond strain dynamics in Ge2_{2}Sb2_{2}Te5_{5} monitored by time-resolved x-ray diffraction

Coherent phonons (CP) generated by laser pulses on the femtosecond scale have been proposed as a means to achieve ultrafast, non-thermal switching in phase-change materials such as Ge$_{2}$Sb$_{2}$Te$_{5}$(GST). Here we use ultrafast optical pump pulses to induce coherent acoustic phonons and stroboscopically measure the corresponding lattice distortions in GST using 100 ps x-ray pulses from the ESRF storage ring. A linear-chain model provides a good description of the observed changes in the diffraction signal, however, the magnitudes of the measured shifts are too large to be explained by thermal effects alone implying the presence of transient non-equilibrium electron heating in addition to temperature driven expansion. The information on the movement of atoms during the excitation process can lead to greater insight into the possibilities of using CP-induced phase-transitions in GST.Comment: 7 pages, 4 figures, Phys. Rev. B, in pres

Graphene‐Like Conjugated Molecule as Hole‐Selective Contact for Operationally Stable Inverted Perovskite Solar Cells and Modules

Further enhancing the operational lifetime of inverted-structure perovskite solar cells (PSCs) is crucial for their commercialization, and the design of hole-selective contacts at the illumination side plays a key role in operational stability. In this work, the self-anchoring benzo[rst]pentaphene (SA-BPP) is developed as a new type of hole-selective contact toward long-term operationally stable inverted PSCs. The SA-BPP molecule with a graphene-like conjugated structure shows a higher photostability and mobility than that of the frequently-used triphenylamine and carbazole-based hole-selective molecules. Besides, the anchoring groups of SA-BPP promote the formation of a large-scale uniform hole contact on ITO substrate and efficiently passivate the perovskite absorbers. Benefiting from these merits, the champion efficiencies of 22.03% for the small-sized cells and 17.08% for 5 × 5 cm2 solar modules on an aperture area of 22.4 cm2 are achieved based on this SA-BPP contact. Also, the SA-BPP-based device exhibits promising operational stability, with an efficiency retention of 87.4% after 2000 h continuous operation at the maximum power point under simulated 1-sun illumination, which indicates an estimated T80 lifetime of 3175 h. This novel design concept of hole-selective contacts provides a promising strategy for further improving the PSC stability.journal articl

Elimination of light-induced degradation at the nickel oxide-perovskite heterojunction by aprotic sulfonium layers towards long-term operationally stable inverted perovskite solar cells

Nickel oxide (NiOx) is a promising hole-selective contact to produce efficient inverted p-i-n structured perovskite solar cells (PSCs) due to its high carrier mobility and high transparency. However, the light-induced degradation of the NiOx–perovskite heterojunction is the main factor limiting its long-term operational lifetime. In this study, we used the time-resolved mass spectrometry technique to clarify the degradation mechanism of the NiOx-formamidinium–methylammonium iodide perovskite (a common composition for high-performance PSCs) heterojunction under operational conditions, and observed that (1) oxidation of iodide and generation of free protons under 1-sun illumination, (2) formation of volatile hydrogen cyanide, methyliodide, and ammonia at elevated temperatures, and (3) a condensation reaction between the organic components under a high vapor pressure. To eliminate these multi-step photochemical reactions, we constructed an aprotic trimethylsulfonium bromide (TMSBr) buffer layer at the NiOx/perovskite interface, which enables excellent photo-thermal stability, a matched lattice parameter with the perovskite crystal, and robust trap-passivation ability. Inverted PSCs stabilized with the TMSBr buffer layer reached the maximum efficiency of 22.1% and retained 82.8% of the initial value after continuous operation for 2000 hours under AM1.5G light illumination, which translates into a T80 lifetime of 2310 hours that is among the highest operational lifetimes for NiOx-based PSCs

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Processes of Professionalization of Teachers as the Technology of Education Quality Management

This article provides an overview of the results of researching the efficiency of the institutes of professional development of education workers of the Krasnoyarsk Territory held in 2009-2010 by the interregional group of researchers from Krasnoyarsk, Moscow, Khabarovsk and the Stavropol Territory at the initiative of Krasnoyarsk Regional Institute of Professional Development and Retraining of Education Workers, Ministry of Education and Science of the Krasnoyarsk Territory. The main objective of the research was determining the main factors, institutes and technology that influence the professional development of teaching staff for potential description of the standard model of professional development of a teacher. During the research the authors have developed a matrix of professionalization including most of professional tasks a teacher solves during his/her professional activities. The matrix can serve as the basis for describing the dynamics of teachers professional development, sequence of controversies appearing in professional activities and changes in the methods of solving case educational tasks. Management aspect of using the matrix of professionalization lies in developing instruments for estimation of the qualification аnd the new type of education workers, which would be based on determining levels and stages of qualification within the field of professional activities.В статье приводятся результаты исследования эффективности институтов профессионализации работников образования Красноярского края, проведенного в 2009- 2010 гг. межрегиональной группой исследователей из Красноярска, Москвы, Хабаровска, Ставропольского края по инициативе Красноярского краевого института повышения квалификации работников образования, министерства образования и науки Красноярского края. Основной целью исследования стало выявление основных факторов, институтов и технологий, влияющих на профессиональное развитие педагогических работников для возможного описания нормативной модели профессионального развития учителя. В ходе проведения исследования авторами была получена матрица профессионализации, в которую вписывается большинство возможных профессиональных задач, которые решает педагог в своей деятельности. Разработанная матрица может служить основанием для описания динамики профессионального развития педагогов, последовательности возникающих противоречий, имеющих свою логику разворачивания в профессиональной деятельности, и смены способа решения ситуативных педагогических задач. Управленческий аспект использования матрицы профессионализации заключается в постановке задачи на разработку инструментов для оценки квалификации работников образования нового типа, основанного на выявлении уровней, ступеней квалификации внутри сферы профессиональной деятельности

Fast Neural Network Engine for Natural Science Language Processing: A Drug-Search Case.

The main advantage of modern natural language processing methods is a possibility to turn an amorphous human-readable task into a strict mathematic form. That allows to extract chemical data and insights from articles and to find new semantic relations. We propose a universal engine for processing chemical and biological texts. We successfully tested it on various use-cases and applied to a case of searching a therapeutic agent for a COVID-19 disease by analyzing PubMed archive

Processes of Professionalization of Teachers as the Technology of Education Quality Management

This article provides an overview of the results of researching the efficiency of the institutes of professional development of education workers of the Krasnoyarsk Territory held in 2009-2010 by the interregional group of researchers from Krasnoyarsk, Moscow, Khabarovsk and the Stavropol Territory at the initiative of Krasnoyarsk Regional Institute of Professional Development and Retraining of Education Workers, Ministry of Education and Science of the Krasnoyarsk Territory. The main objective of the research was determining the main factors, institutes and technology that influence the professional development of teaching staff for potential description of the standard model of professional development of a teacher. During the research the authors have developed a matrix of professionalization including most of professional tasks a teacher solves during his/her professional activities. The matrix can serve as the basis for describing the dynamics of teachers professional development, sequence of controversies appearing in professional activities and changes in the methods of solving case educational tasks. Management aspect of using the matrix of professionalization lies in developing instruments for estimation of the qualification аnd the new type of education workers, which would be based on determining levels and stages of qualification within the field of professional activities.В статье приводятся результаты исследования эффективности институтов профессионализации работников образования Красноярского края, проведенного в 2009- 2010 гг. межрегиональной группой исследователей из Красноярска, Москвы, Хабаровска, Ставропольского края по инициативе Красноярского краевого института повышения квалификации работников образования, министерства образования и науки Красноярского края. Основной целью исследования стало выявление основных факторов, институтов и технологий, влияющих на профессиональное развитие педагогических работников для возможного описания нормативной модели профессионального развития учителя. В ходе проведения исследования авторами была получена матрица профессионализации, в которую вписывается большинство возможных профессиональных задач, которые решает педагог в своей деятельности. Разработанная матрица может служить основанием для описания динамики профессионального развития педагогов, последовательности возникающих противоречий, имеющих свою логику разворачивания в профессиональной деятельности, и смены способа решения ситуативных педагогических задач. Управленческий аспект использования матрицы профессионализации заключается в постановке задачи на разработку инструментов для оценки квалификации работников образования нового типа, основанного на выявлении уровней, ступеней квалификации внутри сферы профессиональной деятельности