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Schreier rewriting beyond the classical setting Dedicated to our teacher Alfred Lvovich Shmelkin on his 70th birthday

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Science China Mathematics 2009年第2期52卷 231-243页

作者： BAHTURIN yuri OLSHANSKII Alexander Department of Mathematics and Statistics Memorial University of Newfoundland St. John'sNL A1C 5S7Canada Department of Algebra Faculty of Mathematics and Mechanics119899 Moscow Russia Department of Mathematics 1326 Stevenson Center Vanderbilt UniversityNashvilleTN 37240 USA

Using actions of free monoids and free associative algebras, we establish some Schreier-type formulas involving ranks of actions and ranks of subactions in free actions or Grassmann-type relations for the ranks of intersections of subactions of free actions. The coset action of the free group is used to establish a generalization of the Schreier formula in the case of subgroups of infinite index. We also study and apply large modules over free associative and free group algebras.

关键词： free algebra group monoid act G-set module

R&D synergy between local and foreign-owned enterprises in post-communist economies

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International Journal of Innovation Studies 2023年第2期7卷 101-114页

作者： Maksim A.Yurevich yuri V.Simachev Michail G.Kuzyk Anna A.Fedyunina Centre for Industrial Policy Studies National Research University Higher Schoolof EconomicMoscowRussia Center for MacroeconomicStudies The Financial University Under the Government of the Russian FederationMoscowRussia

This study examines how internal research and development(R&D),external knowledge acquisition,and R&D contracted with other companies interact in local and foreign-owned enterprises in post-communist economies.A large sample of firm-level data from the Business Environment and Enterprise Performance Survey(BEEPS)across 26 postcommunist countries(including European Union(EU)members and non-EU states of Eastern Europe,Caucasian countries,and Central Asian countries)and country-level data from the Global Innovation Index and the International Property Rights Index were *** findings show that enterprises with majority foreign ownership are relatively more likely to acquire external R&*** demonstrate that the R&D behavior of enterprises with majority foreign ownership and local firms are interrelated,that is,we find a synergy *** to the results,decisions on internal R&D and the purchase of external knowledge for enterprises with majority foreign ownership are similar to those of local ***,enterprises with foreign ownership contract R&D with other companies more often if local firms conduct internal R&*** results indicate the presence of knowledge spillover and cross-learning effects in both types of enterprises in postcommunist ***,we find that the national innovation environment is not significant for the R&D intensity of enterprises with majority foreign ownership,which suggests their high dependence on the parent structures of multinational enterprises.

关键词： Foreign ownership BEEPS R&D Market environment

Atomic-scale mechanisms of void strengthening in tungsten

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Tungsten 2021年第1期3卷 65-71页

作者： yuri N.Osetsky Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA

Neutron and heavy-ion irradiation of tungsten produces nanometer-size vacancy voids,gas-filled bubbles and dislocation *** defect features can a ect mechanical properties and the impact can be quite significant because of their high *** the basic mechanisms of mechanical properties degradation is necessary for predicting radiation e *** can be made using discrete dislocation dynamics or/and finite element approaches which,however,need local interaction mechanisms as *** knowledge can be provided only by atomic-scale *** paper reports the results of an extensive atomic-scale modeling study of the interactions between moving edge dislocations and voids in *** main focus is on the e ects of the void size and ambient *** resolved shear stress was calculated for voids up to 9 nm in *** results are compared with the theoretical approach and with those obtained earlier for voids in body centered cubic(bcc)*** important role of the void surface has been revealed.

关键词： Tungsten Neutron irradiation Voids Radiation-induced hardening Dislocations Dispersed barrier hardening

Evaluation of Energy Saving Operational Modes for Industrial Fracture Connected Processes on the Basis of Incubation Time Fracture Criterion

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Transactions of Tianjin University 2008年第B10期14卷 476-482页

作者： Bratov Vladimir Petrov yuri InstituteofProblemsofMechanicalEngineering 199178St.-PetersburgRussia St.-PetersburgStateUniversity 198504St.-PetersburgRussia

A problem for a central crack in a plate subjected to plane strain conditions is investi-gated. Mode Ⅰ crack loading is created by a dynamic pressure pulse applied at a large distance from the crack. It was found that for a certain combination of amplitude and duration of the pulse applied, the energy transmitted to the sample has a strongly marked minimum, meaning that with the pulse amplitude or duration moving away from the optimal values, minimum energy required for initiation of crack growth increases rapidly. The results obtained indicate a possibility to optimise energy consumption of different industrial processes connected with fracture. Much could be gained in, for example, drilling or rock pounding where energy input accounts for the largest part of the process cost. Presumably further investigation of the effect observed can make it possible to predict optimal energy saving parameters, i.e. frequency and amplitude of impacts, for industrial devices, e.g. bores, grinding machines, and hence significantly reduce the process cost. The pre-diction can be given based on the parameters of the media fractured (material parameters, preva-lent crack length and orientation, etc.).

关键词：平面变形裂纹节能操作破裂标准

Optimization of Crystal Structure Based on Experimentally Obtained XRD Patterns for Fluorescence of Sm³⁺-Doped TiO₂ Thin Films by Machine Learning

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Optics and Photonics Journal 2022年第6期12卷 147-155页

作者： yuri Tamamoto Mariko Murayama Xiwei Zhao Department of Physics Tokyo University of Science Tokyo Japan Research Institute of Industrial Technology Toyo University Saitama Japan Department of Materials Science and Engineering Xihua University Chengdu China

The luminescence intensity of rare-earth ion-doped luminescent materials is closely related to the configuration of the anions around the rare-earth ions added to the host material and the lattice defects. And it is expected that this information will be reflected in the XRD pattern. In this study, the lumines-cence data and XRD patterns of Sm-doped TiO2 accumulated by our group are used to construct a model to predict the integrated luminescence intensity. The model was confirmed to be able to predict the integrated luminescence in-tensity with high accuracy. Furthermore, we found that the integrated lumi-nescence intensity of this system is closely related to the change in the position of the peak on the (200) plane of TiO2.

关键词： Machine Learning Phosphor TiO2

Preparation of a Hybrid Organic-inorganic Monolith for Extraction and Purification of Quercetin and Myricetin from Chamaecyparis obtusa

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Chemical Research in Chinese Universities 2014年第2期30卷 216-221页

作者： ZHU Tao LEE yuri ROW Kyungho School of Chemistry and Chemical Engineering Tianjin University of Technology Tianjin 300384 P.R.China Department of Chemical Engineering Inha University Incheon 402-751 Korea

A new hybrid organic-inorganic monolithic cartridge was synthesized and used as the selective sorbent for the extraction and purification of quercetin and myricetin from Chamaecyparis obtusa via a solid-phase extraction *** morphology of the monolithic material was examined by field emission-scanning electron microscopy and a Brunauer-Emmett-Teller（BET） *** adsorption capacity of the obtained material for quercetin and myricetin was investigated by fitting the adsorption data to four different adsorption equations,of which the LangmuirFreundlich isotherm was selected as the most suitable *** optimized conditions,good calibration curves were observed at nine concentrations ranged from 0.5 μg/mL to 100.0 μg/mL of quercetin and *** extraction recovery ranged from 74.5％ to 84.6％ and the inter-and intra-day relative standard deviations were ＜6％.This type of hybrid monolith has potential for the separation and purification of bioactive compounds from natural plant extracts.

关键词： Extraction Purification Adsorption isotherm Hybrid organic-inorganic monolith Quercetin Myricetin

Mental health research in the Arab region in response to the COVID-19 pandemic:a scoping review

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General Psychiatry 2022年第2期35卷 85-91页

作者： Mohamed Hussein Mahmoud Osman Hassan Ibrahim Hamdy Ezzat Abdelhafez Sami Ouanes Eiman Al-Janahi yuri Zoghbi Ovais Wadoo Mental Health Services Hamad Medical CorporationDohaAd DawhahQatar Department of Neurosurgery Hamad Medical CorporationDohaAd DawhahQatar College of Medicine Qatar UniversityDohaAd DawhahQatar Department of Psychiatry College of MedicineQatar UniversityDohaAd DawhahQatar

Background The ongoing pandemic has led to a global surge in coronavius disease 2019(COVID-19)-related mental health ***,most related publications come from Western countries or China,and their findings cannot alwrays be extrapolated to Arabl *** This study provides a quantitative and qualitative analysis of mental health research pertaining to Arab countries'response to the COVID-19 *** A scoping review of the World Health Organzation(WHO)C0VID-19 database for publications on mental health was conducted by authors afllated *** istutions,including artides from inception to 24 October *** indluded publications were evaluated for their national distribution,international cllaboration,publication type,and main research *** quality analysis of the incuded research studies was performed using the original and mdified versions of the Newcastle Ottawa *** In total,102 articles were included in this study,averaging 4.6 articles per Arab *** of the articles emerged from the Kingdom of Saudi Arabia,Jordan,and Egypt.A majority of publications demonstrated intermational *** of the publications were original research studies and cross sectional in *** predominant research theme was examining the pandemic s mental health effects on the general population and healthcare workers.0nly 28.0% of the studies were of high methodologial quality,where as 41.5% were moderate and 30.5% were low in *** Mental health research in response to the COVID-19 pandemic in the Arab region has quantitative and qualitative *** institutions need torespond to the pandemic prompty in order to address the delineated research gap and to generate higher-quality research output.

关键词： qualitative prompt publications

Recovery of Brachiopod and Ammonoid Faunas Following the End-Permian Crisis:Additional Evidence from the Lower Triassic of the Russian Far East and Kazakhstan

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Journal of Earth Science 2014年第1期25卷 1-44页

作者： yuri D Zakharov Alexander M Popov Far Eastern Geological Institute Far Eastern BranchRussian Academy of Sciences

After the End-Permian mass extinction, ammonoids reached levels of taxonomic diver- sity higher than in the Changhsingian by the Dienerian Substage of the Induan. However, brachiopods exhibit a prolonged delay in recovery, and their taxonomic diversity had not recovered to Late Permian levels even by the Olenekian. The differential patterns of recovery between these two clades may reflect fundamental differences in physiology and behavior. Brachiopods were benthic organisms that were dependent on specific trophic sources, and their general reduction in size during the Early Triassic may have been a response to a relative paucity of food resources. In contrast, ammonoids were sluggish- nektic organisms that utilized a wider range of trophic sources and that suffered no comparable size decrease during the Early Triassic. Brachiopods may have been at a disadvantage also due to vulner- abilities associated with their larval stage, during which they had to locate a suitable substrate for set- tlement. In contrast, ammonoids had no larval stage and juveniles may have been dispersed widely into favorable habitats. These factors may account for differences in the relative success of ammonoids and brachiopods at high-latitude regions following the End-Permian mass extinction： ammonoids success- fully reeolonized the Boreal region during the Early Triassic whereas brachiopods did not.

关键词： Lower Triassic South Primorye Kazakhstan brachiopod ammonoid biotic recovery.

WISE Infrared Search for Young Stellar Objects Associated with Starless Cores

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International Journal of Astronomy and Astrophysics 2023年第2期13卷 89-111页

作者： Susumu Sato yuri Iwamoto Yoichi Itoh Nishi-Harima Astronomical Observatory Center for Astronomy University of Hyogo Hyogo Japan

This study presents the results of an infrared search of young stellar objects (YSOs) associated with cores with high optical extinction and no associated infrared IRAS source. Four hundred YSO candidates were identified in the WISE photometric catalog based on the infrared excess attributed to the circumstellar materials and proto-planetary disks. One-hundred and forty-nine cores do not have YSO candidates. Whereas, 32 cores harbor only Class I candidates and 107 cores have Class II candidates. Ninety-one cores that were previously identified as starless cores, were found to contain YSOs. The ratio of the number of starless cores to the number of star-forming cores suggests that the typical timescale from molecular cloud core formation to the birth of a star is in the range of 0.5 - 1.4 Myr.

关键词： Stars: Formation ISM: Clouds Infrared: Stars