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First record of Cercidiphylloxylon (Cercidiphyllaceae) from the Palaeocene of Fushun,NE China

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Journal of Systematics and Evolution 2010年第4期48卷 302-308页

作者： dmitry GROMYKO Albert G.ABLAEV Department of Palaeobotany Komarov Botanical InstituteRussian Academy of Sciences V.I.Il'ichev Pacific Oceanological Institute Far Eastern BranchRussian Academy of Sciences

Cercidiphylloxylon spenceri(Brett)Pearson is described from the Lizigou Formation,Palaeocene in *** growth rings are distinct;pores are diffuse,solitary,with somewhat angular outlines in cross section;vessel elements long with long scalariform perforation plates;intervessel pitting is opposite to scalariform;fibertracheids are present;axial parenchyma is scarce;rays are mostly biseriate and *** wood characters of the fossil specimen fall into the range of those of extant Cercidiphyllum(Cercidiphyllaceae).The finding is one of the earliest fossil wood records of Cercidiphyllaceae.

关键词： Cercidiphylloxylon Cercidiphyllum fossil wood Fushun Palaeocene

Single‑Photon Sources Based on Novel Color Centers in Silicon Carbide P–I–N Diodes: Combining Theory and Experiment

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Nano-Micro Letters 2021年第5期13卷 192-203页

作者： Igor A.Khramtsov dmitry Yu.Fedyanin Laboratory of Nanooptics and Plasmonics Center for Photonics and 2D MaterialsMoscow Institute of Physics and Technology141700DolgoprudnyRussian Federation

Point defects in the crystal lattice of SiC,known as color centers,have recently emerged as one of the most promising single-photon emitters for non-classical light ***,the search for the best color center that satisfies all the requirements of practical applications has only just *** color centers in SiC have been recently discovered but not yet ***,it is extremely challenging to understand their optoelectronic properties and evaluate their potential for use in practical single-photon ***,we present a theoretical approach that explains the experiments on single-photon electroluminescence(SPEL)of novel color centers in SiC p-i-n diodes and gives the possibility to engineer highly efficient single-photon emitting diodes based on ***,we develop a novel method of determining the electron and hole capture cross sections by the color center from experimental measurements of the SPEL rate and second-order *** other methods,the developed approach uses the experimental results at the single defect level that can be easily obtained as soon as a single-color center is identified in the i-type region of the SiC p-i-n diode.

关键词： Color centers Electron capture cross section Single-photon emitting diodes Single-photon electroluminescence Charge state control

Machine learning for recovery factor estimation of an oil reservoir:A tool for derisking at a hydrocarbon asset evaluation

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Petroleum 2022年第2期8卷 278-290页

作者： Ivan Makhotin Denis Orlov dmitry Koroteev Evgeny Burnaev Aram Karapetyan dmitry Antonenko Skolkovo Institute of Science and Technology MoscowRussia JSC Zarubezhneft MoscowRussia

Well-known oil recovery factor estimation techniques such as analogy,volumetric calculations,material balance,decline curve analysis,hydrodynamic simulations have certain *** techniques are time-consuming,and require specific data and expert ***,though uncertainty estimation is highly desirable for this problem,the methods above do not include this by *** this work,we present a data-driven technique for oil recovery factor(limited to water flooding)estimation using reservoir parameters and representative *** apply advanced machine learning methods to historical worldwide oilfields datasets(more than 2000 oil reservoirs).The data-driven model might be used as a general tool for rapid and completely objective estimation of the oil recovery *** addition,it includes the ability to work with partial input data and to estimate the prediction interval of the oil recovery *** perform the evaluation in terms of accuracy and prediction intervals coverage for several tree-based machine learning techniques in application to the following two cases:(1)using parameters only related to geometry,geology,transport,storage and fluid properties,(2)using an extended set of parameters including development and production *** both cases,the model proved itself to be robust and *** conclude that the proposed data-driven approach overcomes several limitations of the traditional methods and is suitable for rapid,reliable and objective estimation of oil recovery factor for hydrocarbon reservoir.

关键词： Oil recovery factor Machine learning Regression Uncertainty estimation Conformal predictors Clustering Oilfield Oil reservoir

Population-specific effects of temperature and photoperiod on development and body mass in Cassida vibex (Coleoptera: Chrysomelidae)

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Insect Science 2023年第6期30卷 1810-1826页

作者： dmitry Kutcherov Elena B.Lopatina Department of Entomology St.Petersburg State UniversitySt.PetersburgRussia

An interplay of genetic divergence and phenotypic plasticity in shaping geographic variation is increasingly receiving attention in the entomological literature. Two major environmental variables that govern life histories are temperature and photoperiod. Studies of thermal and photoperiodic reaction norms help us understand how insect diversity evolved and how insects respond to environmental change. We studied survival, development, and body mass in three geographic populations of the beetle Cassida vibex reared in the laboratory under several combinations of constant temperature (16, 19, 22, 25, and 28 °C) and photoperiod (short-day and long-day). The three collection sites are situated along a climatic gradient and separated by hundreds of kilometers. Each population subtly but significantly differs in the absolute values of survival rate, developmental rate, and body mass as well as in the thermal and photoperiodic plasticity of these traits, but the geographic differences do not form a latitudinal cline. The southernmost population from a relatively warm climate survives worse at low temperatures than the other two, but the overall survival is lowest in the latitudinally intermediate population. Short-day conditions tend to accelerate postembryonic development and increase the slope of the developmental rate–temperature relationship, especially so in the intermediate population, followed by the southernmost population and then by the northernmost population. The latter, which inhabits a harsh climate, has the fastest and most temperature-sensitive development, regardless of photoperiod, and attains the largest body mass among the three populations. The intermediately located and photoperiodically plastic population, which lives in a cool but mild climate, in contrast, has the smallest body size. Hence, although the importance of short-day conditions as a seasonal cue increases poleward, the photoperiodic responses do not always become more pronounced in colder

关键词： adaptation life history photoperiodism plasticity reaction norm temperature

Soil respiration in paludified forests of European Russia

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Journal of Forestry Research 2020年第5期31卷 1939-1948页

作者： dmitry Ivanov Fedor Tatarinov Julia Kurbatova A.N.Severtsov Institute of Ecology and Evolution RAS Leninsky Prospekt 33MoscowRussia 119071 Weizmann Institute of Science Herzl St 23476100 RehovotIsrael

Soil respiration studies in paludified forests of the European part of Russia are quite rare in comparison with those of open peat bogs,which make long-term observations in this region highly *** this study,soil CO2 emissions were measured by the close chamber method in different microlandscapes of paludified *** four summer seasons with different environments,soil respiration ranged from 1078 to 248 mg CO2 m^-2 h^-1 in a paludified spruce forest site with coarse woody debris to 659–820 mg CO2 m^-2 h^-1 in a paludified boggy pine *** most intensive soil respiration was observed during the hot summer of 2013 and the lowest in the hot and humid summer of *** total soil CO2 emissions in paludified forests in 2015–2016 were approximately 2000–3000 g CO2 *** the year,the lowest CO2 emission values were observed from November to April(14–84 mg CO2 m^-2 h^-1)and the maximum were in July and August(522–1205 mg CO2 m^-2 h^-1).The contributions of CO2 emissions in the cold November–April period were 6–8.5%.The impacts of temperature on soil respiration were higher(r2=0.45–0.57)than those of groundwater levels(r^2=0.17–0.49).Soil respiration in the paludified spruce forest and in the pine bog generally were higher than emissions from ecosystems with similar hydrothermal conditions in the boreal zone.

关键词： Carbon flux Chamber measurements CO2 emission Peatlands Southern taiga

Theoretical models for irradiation hardening and embrittlement in nuclear structural materials:a review and perspective

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Acta Mechanica Sinica 2020年第2期36卷 397-411页

作者： Xiazi Xiao dmitry Terentyev Haijian Chu Huiling Duan Department of Mechanics School of Civil EngineeringCentral South UniversityChangsha 410075China Structural Materials Group Institute of Nuclear Materials ScienceSCK-CEN2400 MolBelgium Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China CAPT HEDPS and IFSA CollaborativeInnovation Center of MoEBIC-ESATPeking UniversityBeijing 100871China

The study of irradiation hardening and embrittlement is critically important for the development of next-generation structural materials tolerant to neutron irradiation,and could dramatically affect the approach to the design of components for advanced nuclear *** addition,a growing interest is observed in the field of research and development of irradiation-resistant *** review aims to provide an overview of the theoretical development related to irradiation hardening and embrittlement at moderate irradiation conditions achieved in recent years,which can help extend our fundamental knowledge on nuclear structural *** a general introduction to the irradiation effects on metallic materials,recent research progress covering theoretical modelling is summarized for different types of structural *** fundamental mechanisms are elucidated within a wide range of temporal and spatial *** review closes with the current understanding of irradiation hardening and embrittlement,and puts some perspectives deserving further study.

关键词： Irradiation hardening Irradiation embrittlement Theoretical models Fundamental mechanisms

Comparison of linear and nonlinear extreme wave statistics

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Acta Oceanologica Sinica 2016年第5期35卷 99-105页

作者： dmitry Chalikov ALEXANDER V.Babanin Swinburne University of Technology Victoria 3122 Australia P.P. Shirshov Institute of Oceanology Saint-Petersburg 199053 Russia

An extremely large（＂freak＂） wave is a typical though rare phenomenon observed in the sea. Special theories（for example, the modulation instability theory） were developed to explain mechanics and appearance of freak waves as a result of nonlinear wave-wave interactions. In this paper, it is demonstrated that the freak wave appearance can be also explained by superposition of linear modes with the realistic spectrum. The integral probability of trough-to-crest waves is calculated by two methods： the first one is based on the results of the numerical simulation of a wave field evolution performed with one-dimensional and two-dimensional nonlinear *** second method is based on calculation of the same probability over the ensembles of wave fields constructed as a superposition of linear waves with random phases and the spectrum similar to that used in the nonlinear simulations. It is shown that the integral probabilities for nonlinear and linear cases are of the same order of values

关键词： freak waves numerical modeling probability of linear and nonlinear waves ensemble modeling

Laboratory investigation of a new scale inhibitor for preventing calcium carbonate precipitation in oil reservoirs and production equipment

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Petroleum Science 2016年第2期13卷 320-327页

作者： Azizollah Khormali dmitry G.Petrakov Department of Oil and Gas Field Development and Operation Oil and Gas FacultyNational Mineral Resources University(Mining University)

The formation of mineral scale is a complex problem during the oilfield operations. Scale inhibitors are widely used to prevent salt precipitation within reservoirs, in downhole equipment, and in production facilities. The scale inhibitors not only must have high effectiveness to prevent scale formation, but also have good adsorption- desorption characteristics, which determine the operation duration of the scale inhibitors. This work is focused on the development of a new scale inhibitor for preventing cal- cium carbonate formation in three different synthetic for- mation waters. Scale inhibition efficiency, optical density of the solution, induction time of calcium carbonate for- mation, corrosion activity, and adsorption-desorption ability were investigated for the developed scale inhibitor. The optimum concentration of hydrochloric acid in the inhibitor was determined by surface tension measurement on the boundary layer between oil and the aqueous scale inhibitor solution. The results show that the optimum mass percentage of 5 % hydrochloric acid solution in the inhi- bitor was in the range of 8 % to 10 %. The new scale inhibitor had high efficiency at a concentration of 30 mg/L. The results indicate that the induction period for calcium carbonate nucleation in the presence of the new inhibitor was about 3.5 times longer than the value in the absence of the inhibitors. During the desorption process at reservoir conditions, the number of pore volumes injected into the carbonate core for the developed inhibitor was significantly greater than the volume of a tested industrial inhibitor, showing better adsorption/desorption capacity.

关键词： Scale inhibitor Desorption Corrosionactivity - Precipitation Optical density

Russian school of the theory and geometry of gearing： Its origin and golden period （1935-1975）

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Frontiers of Mechanical Engineering 2016年第1期11卷 44-59页

作者： dmitry BABICHEV Sergey LAGUTIN Natalya BARMINA Department of Applied Mechanics Tyumen State Oil and Gas University Tyumen 625000 Russia Electrostal Plant of Heavy Machine Engineering Electrostal City144012 Russia Institute of Mechanics Kalashnikov Izhevsk State Technical Universitylzhevsk 426069 Russia

During the second half of the twentieth century, Soviet scientists were among the world leaders in the theory and geometry of gearing or the theoretical fundamentals of designing gears and gear-cutting tools. The authors of the current paper review works related to the development of the theory of gearing （TG） written in Russian from the mid-1930s to the present. Overall, the review covers more than 400 publications of nearly 200 authors （among more than 1000 studied works）. This review involves some works on gear strength and accuracy to attract more experts. This paper presents a short list of works from the seventeenth century to the nineteenth century and discusses the basic concepts of the TG. This paper also includes a review of more than 160 papers in Russian for the period of 1935-1975, which is the ＂golden age＂ of the TG. The main features and achievements during this period are also considered. The distinctive feature of this review is the use of diagrams that visually present TG experts and the dates and themes of their published works. The diagrams also show the following aspects： 1） The most popular and important themes in a specific period, 2） the most important publications on the themes of interest to readers, and 3） the direction of the works and scope of interests of every researcher.

关键词： theory of gearing (TG) gear geometry,generating surface gear synthesis gear analysis