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Design of broadband terahertz vector and vortex beams: II. Holographic assessment

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Light(Advanced Manufacturing) 2022年第4期3卷 14-26页

In this paper,we demonstrate the capabilities of the terahertz pulse time-domain holography in visualisation,simulation,and assessment of broadband THz vortex beam formation dynamics upon its shaping by elements of beam converter,and further propagation and *** adding Jones matrix formalism to describe broadband optical elements,we highlight the differences in the spatio-spectral and spatio-temporal structure of the formed vortex and vector beams dependence on the modulator used and visualise their modal *** influence of diffraction field structure from each element in the broadband vortex modulator is revealed in numerical simulation and the formed beams are analysed against the simplified Laguerre-Gaussian beam model.

关键词： Terahertz radiation vortex beams vector beams Achromatic wave plates Broadband terahertz radiation Digital holography Terahertz holography

Optimal control of natural resources in mining industry

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International Journal of Mining Science and Technology 2015年第2期25卷 193-198页

作者： petrov nikolay Tanev Angel Electrical Engineering Electronics and AutomationTechnical University-Sofia Faculty of Mathematics and Informatics Sofia University

The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine＇s maintenance. Fol- lowing the proposed optimal control model, a sensitivity analysis has been performed that includes the interest rate impact on the optimal solution. This study shows that the increasing of the interest rate sti- mulates faster extraction of the resources. The discounting factor induces that the resource has to be extracted faster hut this effect is counterbalanced by the diminishing returns of the annual cash flow. At higher parameters of ＂alpha＂ close to one of the power function about 80% from the whole resource will be extracted during the first 4 years of object/mine maintenance. An existence of unique positive root with respect to return of investment has been proposed and proved by two ways： by the ＂method of chords＂ and by using specialized software.

关键词： Optimal control Natural resources Interest rate Sensitivity analysis Method of chords

pRb-E2F signaling in life of mesenchymal stem cells:Cell cycle,cell fate,and cell differentiation

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Genes & Diseases 2014年第2期1卷 174-187页

作者： Boris Popov nikolay petrov Institute of Cytology Russian Academy of SciencesSt.Petersburg4Tikhoretsky Av.194064Russia

Mesenchymal stem cells(MSCs)are multipotent cells that can differentiate into various mesodermal lines forming fat,muscle,bone,and other lineages of connective *** possess plasticity and under special metabolic conditions may transform into cells of unusual phenotypes originating from ecto-and *** transplantation,MSCs release the humoral factors promoting regeneration of the damaged *** last five years,the numbers of registered clinical trials of MSCs have increased about 10 *** gives evidence that MSCs present a new promising resource for cell therapy of the most dangerous *** efficacy of the MSCs therapy is limited by low possibilities to regulate their conversion into cells of damaged tissues that is implemented by the pRb-E2F *** widely accepted viewpoint addresses pRb as ubiquitous regulator of cell cycle and tumor ***,current publications suggest that basic function of the pRb-E2F signaling in development is to regulate cell fate and *** facultative and constitutive chromatin modifications,pRb-E2F signaling promotes transient and stable cells quiescence,cell fate choice to differentiate,to senesce,or to *** of pRb is associated with cancer cell *** regulates cell fate by retaining quiescence of one cell population in favor of commitment of another or by suppression of genes of different cell *** is the founder member of the“pocket protein”family possessing functional *** increase in the efficacy of the MSCs based cell therapy will depend on precise understanding of various aspects of the pRb-E2F signaling.

关键词： Cell cycle Cell differentiation Cell fate Mesenchymal stem cells pRb-E2F signaling

Call for Papers:“Cultural Economy and the Economisation of Culture in the System of Modern Societies”:The Seventh International Forum on Marxist Aesthetics

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马克思主义美学研究 2017年第2期 18-19页

作者： Alexander v.petrov Wang Jie the Russian-Chinese Center for Comparative Social Economic and Political ResearchesDepartment of Sociology Saint Petersburg State University Zhejiang University the journal Research on Marxist Aesthetics

(Department of Sociology,Saint Petersburg State University;College of Media and International Culture,Zhejiang University)We are pleased to announce the Seventh International Forum on Marxist Aesthetics to be held on October,2018,at the University of ***,*** with the past forums the aim of the next one is to offer a meeting ground

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INCUBATION TIME CONCEPT IN PROBLEMS OF PULSED STRENGTH OF CONTINUA:FRACTURE,CAvITATION,AND ELECTRICAL BREAKDOWN

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INCUBATION TIME CONCEPT IN PROBLEMS OF PULSED STRENGTH OF CO...

Specificity of electrophysical and gas-sensitive properties of nanocomposite ZnO–TiO_(2) films formed by solid-phase pyrolysis

祝贺郑哲敏先生八十华诞应用力学报告会

作者： Yuri v.petrov St.-Petersburg State University NIIMMUniversitetsky Prospect28PetrodvoretsSt.-Petersburg199178Russia

Experiments on the dynamic fracture of solids,hquids,conductors,andinsulators that is caused by fast intense actions of environment or directed energy fluxesreveal a number of effects indicating a fundamental difference between the fast dynamicrupture(breakdown)of materials and a similar process under slow quasistatic *** example,one of the basic problems in testing the dynamic-strength properties of ma-terials is associated with the dependence of the limiting characteristics on the duration,amplitude,and growth rate of an external action,as well as on a number of other *** a critical value is a constant for a material in the static case,experimentallydetermined critical characteristics in dynamics are strongly unstable,and as a result,their behavior becomes *** indicated(and some other)features of thebehavior of materials subjected to pulsed actions are common for a number of seeminglyquite different paysical processes,such as dynamic fracture(starting cracks and scab-bing),cavitation in liquids,and electrical breakdown in *** this paper,we analyzeexamples illustrating typical dynamic effects inherent in these *** propose aunified interpretation for the fracture of solids and liquids and electrical breakdown ininsulators using the structural-time approach[1,2]based on the concept of the fractureincubation time.

关键词： pulsed strength incubation time spalling fracture cavitation in fluids electrical breakdown

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ChemPhysMater

ChemPhysMater 2024年第3期3卷 314-319页

作者： victor v.petrov Maria G.volkova Alexsandra P.Ivanishcheva Gleb v.Tolstyak Ekaterina M.Bayanb Institute of Nanotechnologies Electronicsand Equipment EngineeringSouthern Federal UniversityTaganrog 347922Russia Faculty of Chemistry Southern Federal UniversityRostov-on-Don 344090Russia

ZnO–TiO_(2) thin films containing 0.5 mol%,1.0 mol%,and 5.0 mol%ZnO were synthesized by oxidative solidphase *** materials contained anatase and rutile phases with particle size of 6–13 nm,as confirmed using X-ray phase analysis and scanning electron *** a certain number of ZnO crystallites appeared in the TiO_(2) film structure in the temperature range of room temperature to 220℃,a two-level response of the film resistance was observed,differing by approximately 10%,as obtained by electrophysical *** two-level response correlates with the formation of two donor energy levels of 0.28 and 0.33 ev in the band structure of the ZnO–TiO_(2) *** donor level with a higher activation energy corresponded to the Ti vacancy(v−Ti),and that with a lower activation energy corresponded to the Zn vacancy(v−Zn).Two levels of gas-sensitive properties were noted for 0.5ZnO–TiO_(2),1ZnO–TiO_(2),and 5ZnO–TiO_(2) under the influence of 50 ppm NO_(2) at 250℃.Such two-level responses can be ascribed to the pinning of the Fermi level on ZnO and TiO_(2) *** mechanism of the beak-shaped and two-level responses of sensors based on composite nanomaterials when exposed to various gases was elucidated.

关键词： Thin film ZnO TiO_(2) Nanocomposites Pyrolysis Gas sensors

Incubation time approach in rock fracture dynamics

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 78-85页

作者： SMIRNOv v.petrov Yuri v BRATOv v St.-Petersburg State Transport University 198103 St.-Petersburg Russia St.-Petersburg State University 198504 St.-Petersburg Russia Institute of Problems of Mechanical Engineering Russian Academy of Sciences 199178 St.-Petersburg Russia

The paper is summarizing latest results connected with application of the incubation time approach to problems of dynamic fracture of rock materials. Incubation time based fracture criteria for intact media and media with cracks are discussed. Available experimental data on high rate fracture of different rock materials and incubation time based fracture criteria are used in order to evaluate critical parameters of causing fracture in these materials. Previously discovered possibility to optimize (minimize) energy input for fracture is discussed in connection to industrial rock fracture processes. It is shown that optimal value of momentum associated with critical load in order to initialize fracture in rock media does strongly depend on the incubation time and the impact duration. Existence of optimal load shapes minimizing momentum for a single fracturing impact or a sequence of periodic fracturing impacts is demonstrated.

关键词： incubation time dynamic fracture rocks dynamic strength fracture toughness crack resistance energy and momentum input fracture process optimization

A new insight into the nature of seasonal variations in coordinate time series of GPS sites located near active faults

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Frontiers of Earth Science 2016年第3期10卷 560-569页

作者： Sergey v. TROFIMENKO victor G. BYKOv nikolay v. SHESTAKOv nikolay N. GRIB Hiroaki TAKAHASHI Institute of Tectonics and Geophysics Far Eastern Branch Russian Academy of Sciences Khabarovsk 680000 Russia North-Eastern Federal University Neryungri 678960 the Republic of Sakha (Yakutia) Russia Institute for Applied Mathematics Far Eastern Branch Russian Academy of Sciences Vladivostok 690041 Russia Far Eastern Federal University Vladivostok 690041 Russia Institute of Seismology and volcanology Graduate School of Science Hokkaido University Sapporo 060-0810 Japan

This study provides new insights into the nature of seasonal variations in coordinate time series of GPS sites located near active faults and methods of their modeling. Monthly averaged coordinate time series were analyzed for several pairs of collocated GPS sites situated near the active fault intersection area, in close proximity to the central part of the northern boundary of the Amurian plate and the vicinity of the San Andreas Fault zone. It is concluded that the observed seasonal variations are best described by a breather function which is one of the solutions of the well-known sine-Gordon equation. The obtained results suggest that, in this case, the source of seasonal variations may be caused by the appearance of solitary strain waves in the fault intersection system, which may be qualitatively treated as standing waves of compression-extension of the geological medium. Based on statistical testing, the limits of applicability of the suggested model have been established.

关键词： space geodetic surveys oscillatory move-ments of crustal blocks seasonal variations Amurianmicroplate

Bad News—The Dominant Causes of the Earth’s Global Warming Are Processes on the Sun, and Humanity Can Do Nothing or Little to Stop It?

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Journal of High Energy Physics, Gravitation and Cosmology 2024年第4期10卷 1388-1411页

作者： nikolay petrov Takuchev Trakia University Stara Zagora Bulgaria

Arguments that global warming in the Earth’s atmosphere of the last 70 years is partially or entirely caused by changes in the solar magnetic field are presented in the work. Global warming is probably a consequence of ionizing radiation emitted from the Sun mainly in the “rise” phase of solar activity. The ionizing radiation is positively charged particles with high energy. They penetrate deep into the Earth’s atmosphere, creating increased content of ions serving as condensation nuclei. The condensation nuclei increase cloudiness in the lower atmosphere and lower the surface air temperature. When solar activity decreases as observed in the last 70 years, the reverse process occurs— cloud cover decreases, more solar electromagnetic radiation reaches the earth’s surface and increases the temperature. An additional argument for the presence of high-energy radiation that penetrates deeply into the Earth’s atmosphere and even reaches the Earth’s surface is the high statistically significant correlation between the fluxes of such radiation recorded by GOES series satellites in a geostationary orbit (36,000 km above the Earth’s surface) and the human mortality from deadliest diseases.

关键词： Global Warming Climate Change Solar Cycle Ionizing Radiation Satellite Data