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An Overview of Rationalization Theories of Non-simply Connected Spaces and Non-nilpotent Groups

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Acta Mathematica Sinica,English Series 2022年第10期38卷 1705-1721页

作者： Sergei O.ivanov Laboratory of Modern Algebra and Applications St.Petersburg State University14th Line29bSaint Petersburg199178Russia

We give an overview of five rationalization theories for spaces(Bousfield-Kan’s Q-completion;Sullivan’s rationaliz ation;Bousifeld’s homology rationaliz ation;Casacuberta-Peschke’s Ω-rationalization;Gomez-Tato-Halperin-Tanré’s π-fiberwise rationalization)that extend the classical rationalization of simply connected spaces.We also give an overview of the corresponding rationalization theories for groups(Q-completion;HQ-localization;Baumslag rationalization)that extend the classical Malcev completion.

关键词： Rationalisation localisation rational homotopy theory group theory

Generalized Logan’s Problem for Entire Functions of Exponential Type and Optimal Argument in Jackson’s Inequality in L2（R3）

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Acta Mathematica Sinica,English Series 2018年第10期34卷 1563-1577页

作者： Valerii ivanov Alexey ivanov Department of Applied Mathematics and Computer Science Tula State University

We study Jackson＇s inequality between the best approximation of a function f∈ L2（R^3） by entire functions of exponential spherical type and its generalized modulus of continuity. We prove Jackson＇s inequality with the exact constant and the optimal argument in the modulus of continuity. In particular, Jackson＇s inequality with the optimal parameters is obtained for classical modulus of continuity of order r and Thue-Morse modulus of continuity of order r∈ N. These results are based on the solution of the generalized Logan problem for entire functions of exponential type. For it we construct a new quadrature formulas for entire functions of exponential type.

关键词： Best approximation generalized modulus of continuity Jackson＇s inequality optimal argument Logan＇s problem quadrature formula

Preparation and Properties of Foam Glass-ceramic from Diatomite

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Journal of Wuhan University of Technology(Materials Science) 2018年第2期33卷 273-277页

作者： ivanov KS Institute of the Earth Cryosphere Siberian Branch of Russian Academy of Sciences Tyumen 625026 Russia Tyumen Industrial University Tyumen 625000 Russia

The results of the study of raw mix preparation and foam glass-ceramics production using diatomite as a raw material were presented in the following article. A mixture of diatomite and 40% NaOH solution was subjected to heating at a constant temperature of 775 ℃. Samples of foam glass-ceramic from diatomite with an average density of 290-580 kg/m^3, compressive strength of 1.7-7.8 MPa and thermal conductivity of 0.08-0.14 W/（m·K） were obtained. The investigations have shown that the hydrothermal pretreatment of mixture at the temperature of 90 ℃ may lead to the acceleration of the leaching of amorphous SiO_2 from diatomite. It was discovered that the resulting soluble alkali silicates promote the process of foaming during heating and reduce the average density of the obtained samples. The optimal duration of the leaching process was estimated to be 30 minutes, which corresponds to the yield of SiO_2 equal to 42.5% by the weight of dry diatomite.

关键词： diatomite liquid glass foam glass-ceramics

Theory of adaptive mechanical drive

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Theoretical & Applied Mechanics Letters 2021年第4期11卷 219-223页

作者： K.S.ivanov Almaty University of Power Engineering and Telecommunication Almaty050013Kazakhstan

A kinematic chain with two degrees of freedom and one input can have definability of motion only if there is an additional constraint of forces and velocities.Such a chain is a mechanism that has the brand new property of force adaptation.The article presents a kinematic and force analysis of two-mobile adaptive mechanisms and describes the principle of definability of motion.

关键词： Two-mobile mechanism Definability of motion Force-speed constraint

International scientific communications in the field of colorectal tumour markers

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World Journal of Gastrointestinal Surgery 2017年第5期9卷 127-138页

作者： Krasimir ivanov Ivan Donev Department of General and Operative Surgery Professor Paraskev Stoyanov Medical University of Varna Clinic of Medical Oncology St. Marina University Hospital of Varna

AIM To analyze scientometrically the dynamic science internationalization on colorectal tumour markers as reflected in five information portals and to outline the significant journals, scientists and institutions.METHODS A retrospective problem-oriented search was performed in Web of Science Core Collection(Wo S), MEDLINE, BIOSIS Citation Index(BIOSIS) and Scopus for 1986-2015 as well as in Dervent Innovations Index(Derwent) for 1995-2015. Several specific scientometric parameters of the publication output and citation activity were comparatively analyzed. The following scientometric parameters were analyzed:(1) annual dynamics of publications;(2) scientific institutions;(3) journals;(4) authors;(5) scientific forums;(6) patents-number of patents, names and countries of inventors, and(7) citations(number of citations to publications by single authors received in WoS, BIOSIS Citation Index and Scopus).RESULTS There is a trend towards increasing publication output on colorectal tumour markers worldwide along with high citation rates. Authors from 70 countries have published their research results in journals and conference proceedings in 21 languages. There is considerable country stratification similar to that in most systematic investigations. The information provided to end users and scientometricians varies between these data-bases in terms of most parameters due to different journal coverage, indexing systems and editorial policy. The lists of the so-called "core" journals and most productive authors in Wo S, BIOSIS, MEDLINE and Scopus along with the list of the most productive authors-inventors in Derwent present a particular interest to the beginners in the field, the institutional and national science managers and the journal editorial board members. The role of the purposeful assessment of scientific forums and patents is emphasized. CONCLUSION Our results along with this problem-oriented collection containing the researchers' names, addresses and publications could contribute to a more effective internati

关键词： Colorectal tumour markers Scientometrics International scientific communications Web of Science MEDLINE BIOSIS Scopus Derwent

Assessing suspended sediment fluxes with acoustic Doppler current profilers:case study from large rivers in Russia

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Big Earth Data 2022年第4期6卷 504-526页

作者： Sergey Chalov Vsevolod Moreido Victor ivanov Aleksandra Chalova Faculty of Geography Lomonosov Moscow State UniversityMoscowRussia Institute of Physics Kazan Federal UniversityKazanRussia Flood Hydrology Lab Water Problems Institute of Russian Academy of SciencesMoscowRussia

Surrogate measures are becoming increasingly used to measure suspended sediment flux,but only few particular computer techniques of data processing are recently developed.This study demonstrates capabilities of acoustic Doppler current profilers(ADCPs)to infer information regarding suspended-sand concentrations in river systems and calculate suspended sediment flux via big data analytics which includes process of analyzing and data mining of measurements based on ADCP signal backscatter intensity data.We present here specific codes done by R language using RStudio software with open-source tidyverse and plotly packages aimed to generate tables containing data of suspended load for cells,verticals and whole cross-section based on backscattering values from 600 kH Teledyne RDInstruments RioGrande WorkHorse ADCP unit,as well perform estimates of morphometric,suspended sediment concentration(SSC)and velocity characteristics of the flow.The developed tools enabled to process large data array consisting of over 56,526,480 geo-referenced values of river depth,streamflow velocity,and backscatter intensity for each river cross-section measured at six case study sites in Russia.

关键词： Big data ADCP backscatter intensity sediment transport

Transverse magnetoresistance peculiarities of thermoelectric Lu-doped Bi_2Te_3 compound due to strong electrical disorder

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Journal of Rare Earths 2019年第3期37卷 292-298页

作者： Oleg ivanov Maxim Yaprintsev Elena Danshina Belgorod State University Belgorod State Technological University named after V.G.Shukhov

The n-type thermoelectric Bi_(1.9)Lu_(0.1)Te_3 was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magneto resistance measured within temperature 2-200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-inmagnetic field contribution to the total magneto resistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magneto resistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi_(1.9)Lu_(0.1)Te_3 structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound.

关键词： Bismuth telluride Linear positive magnetoresistance Semiconductors Thermoelectric material Carrier mobility Kohler’s rule

Identification of Proteins and Genes Associated with Hedgehog Signaling Pathway Involved in Neoplasm Formation Using Text-Mining Approach

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Big Data Mining and Analytics 2024年第1期7卷 107-130页

作者： Nadezhda Yu.Biziukova Sergey M.ivanov Oga A.Tarasova Department of Bioinformatics Institute of Biomedical ChemistryMoscow 119121Russia Department of Bioinformatics Pirogov Russian National Research Medical UniversityMoscow 117997Russia

Analysis of molecular mechanisms that lead to the development of various types of tumors is essential for biology and medicine,because it may help to find new therapeutic opportunities for cancer treatment and cure including personalized treatment approaches.One of the pathways known to be important for the development of neoplastic diseases and pathological processes is the Hedgehog signaling pathway that normally controls human embryonic development.Systematic accumulation of various types of biological data,including interactions between proteins,regulation of genes transcription,proteomics,and metabolomics experiments results,allows the application of computational analysis of these big data for identification of key molecular mechanisms of certain diseases and pathologies and promising therapeutic targets.The aim of this study is to develop a computational approach for revealing associations between human proteins and genes interacting with the Hedgehog pathway components,as well as for identifying their roles in the development of various types of tumors.We automatically collect sets of abstract texts from the NCBI PubMed bibliographic database.For recognition of the Hedgehog pathway proteins and genes and neoplastic diseases we use a dictionary-based named entity recognition approach,while for all other proteins and genes machine learning method is used.For association extraction,we develop a set of semantic rules.We complete the results of the text analysis with the gene set enrichment analysis.The identified key pathways that may influence the Hedgehog pathway and their roles in tumor development are then verified using the information in the literature.

关键词： text-mining data mining Hedgehog pathway neoplastic processes enrichment analysis pathology molecularmechanisms

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电流互感器饱和及其对差动保护的音响的研究

电流互感器饱和及其对差动保护的音响的研究

作者： ivanov Nikita 华北电力大学(北京)

学位级别：硕士

电流互感器饱和会导致二次电流失真。电流互感器的误差随着饱和而急剧增加,因为磁化电流不成比例地增加到初级电流。本文研究了直流电流分量和剩余磁化强度对CT饱和度的影响。当外部磁场的方向与残余感应的符号一致时,残余感应的影响更... 详细信息

电流互感器饱和会导致二次电流失真。电流互感器的误差随着饱和而急剧增加,因为磁化电流不成比例地增加到初级电流。本文研究了直流电流分量和剩余磁化强度对CT饱和度的影响。当外部磁场的方向与残余感应的符号一致时,残余感应的影响更大。Jiles-Atherton铁磁滞后方法是广泛用于电磁暂态仿真的方法。论文在MATLAB和Simulink中总结了Jiles-Atherton模型的不同模型和实现。饱和电流互感器对差动继电保护的运行有影响,可导致其非选择性运行,特别是在外部短路模式下。因此,为了正确操作差动继电保护,必须正确检测饱和过程并采取适当的措施。在论文中关于电力系统部分的例子,在Simulink中对各种短路模式进行了仿真和分析。获得的研究结果可能是进一步发展检测电流互感器饱和度的全新方法的有力背景。

关键词：电流互感器饱和 Jiles-Atherton的模型直流电流分量残余磁感应差动保护 MATLAB Simulink