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Generation of dual and quad‑optical frequency combs in the injected radiation free mode‑locked frequency‑shifted feedback laser

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Frontiers of Optoelectronics 2023年第3期16卷 43-56页

作者： Sergey N.Mantsevich Ekaterina i.Kostyleva Andrey N.Danilin vladimir S.Khorkin Physics Department M.V.Lomonosov Moscow State UniversityMoscow 119991Russia Russian Quantum Center(RQC) Skolkovo 143026Russia

The results of an optoelectronic system—frequency-shifted feedback(FSF)laser experimental examination are *** considered FSF laser is seeded only with optical amplifer spontaneous emission(ASE)and operates in the mode-locked regime,whereby the output radiation is sequence of short pulses with a repetition rate determined by the delay time in its optical feedback *** the frequency domain,the spectrum of such a pulse sequence is an optical frequency comb(OFC).These OFCs we call *** consider the possibility of tunable acousto-optic(AO)dual and quad-comb frequency spacing downconversion in the FSF laser seeded with ASE and operating in the mode-locked *** examined system applies a single frequency shifting loop with single AO tunable flter as the frequency shifter that is fed with several radio frequency signals *** initial OFCs with frequency spacing of about 6.5 MHz may be obtained in the wide spectral range and their width,envelope shape and position in the optical spectrum may be *** dual-combs are obtained with a pair of initial OFCs aroused by two various ultrasound waves in the acousto-optic tunable flter(AOTF).The dual-combs frequency spacing is determined by the frequency diference of the signals applied to the AOTF piezoelectric transducer and can be tuned *** quad-combs are obtained with three initial OFCs,forming a pair of dual-combs,appearing when three ultrasound frequencies feed the AOTF *** quad-combs frequency spacing is defned by the diference between the frequency spacing of ***-combs with more than 5000 spectral lines and tunable frequency spacing are *** successive frequency downconversion gives the possibility to reduce the OFC frequency spacing form several MHz for initial OFC to tens of kHz for quad-combs.

关键词： Frequency-shifted feedback laser Optical frequency combs Acousto-optics Dual-combs Quad-combs

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Post-seismic relaxation from geodetic and seismic data

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Geodesy and Geodynamics 2017年第1期8卷 13-16页

作者： Mikhail V.Rodkin vladimir i.Kaftan institute of Earthquake Prediction Theory and Mathematical Geophysics Russian Academy of Sciences institute of Marine Geology and Geophysics FEB RAS Geophysical Center Russian Academy of Sciences(GC RAS) Peoples' Friendship University of Russia PFUR

We have examined the aftershock sequence and the post-seismic deformation process of the Parkfield earthquake （2004, M = 6, California, USA） source area using GPS data. This event was chosen because of the possibility of joint analysis of data from the rather dense local GPS network （from SOPAC internet archive） and of the availability of the rather detailed aftershock sequence data （http：]/***[ ncedc[***）. The relaxation process of post-seismic deformation prolongs about the same 400 days as the seismic aftershock process does. Thus, the aftershock process and the relaxation process in deformation could be the different sides of the same process. it should be noted that the ratio of the released seismic energy and of the GPS obtained deformation is quite different for the main shock and for the aftershock stage. The ratio of the released seismic energy to the deformation value decreases essentially for the post-shock process. The similar change in the seismic energy[deformation value ratio is valid in a few other strong earthquakes. Thus, this decrease seems typical of aftershock sequences testifying for decrease of ratio of elastic to inelastic deformation in the process of post-shock relaxation when the source area appears to be mostly fractured after the main shock occurs, but the healing process had no yet sufficient time to develop.

关键词： Post-seismic relaxationEarth's surface deformationGPSpost-shock fracturing

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Titanium oxide artificial synaptic device:Nanostructure modeling and synthesis,memristive cross-bar fabrication,and resistive switching investigation

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Nano Research 2023年第7期16卷 10222-10233页

作者： Vadim i.Avilov Roman V.Tominov Zakhar E.Vakulov Lev G.Zhavoronkov vladimir A.Smirnov Research Laboratory Neuroelectronics and Memristive Nanomaterials(NEUROMENA Lab) Southern Federal UniversityTaganrog 347922Russia institute of Nanotechnologies Electronics and Electronic Equipment EngineeringSouthern Federal UniversityTaganrog 347922Russia

The paper shows the results of the mathematical model development and the numerical simulation of the oxygen vacancies,and the distribution of TiO,Ti_(2)O_(3),and TiO_(2)oxides in the titanium oxide nanostructure obtained by local anodic oxidation(anodization).The effect of the anodization voltage pulse duration and amplitude on the titanium oxide composition distribution and the conduction channel formation was *** device prototypes based on electrochemical titanium oxide are fabricated and *** was shown that forming free resistive switching between the low resistances state(LRS)1.43±0.54 kΩand the high resistance state(HRS)28.75±9.75 kΩwere observed during 100,000 switching cycles and LRS 1.49±0.23 kΩwas maintained for 10,000 *** resistive switching of the synaptic device prototype was *** was shown that increasing Uset from 0.5 to 1.5 V leads to different LRS from 3.96±0.19 to 0.71±0.10 kΩ.The results obtained can be used in the development of technological foundations for the formation of high-performance multilevel artificial synapses for elements of neuroelectronics and hardware neural networks.

关键词： artificial intelligence neuromorphic systems memristive cross bar resistive switching scanning probe microscopy titanium oxide

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Technological lubricating means： Evolution of materials and ideas

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Frontiers of Mechanical Engineering 2016年第1期11卷 101-107页

作者： vladimir A. GODLEVSKiY Department of Physics Ivanovo State University Ivanovo 153025Russia

The main stages of technological lubricating material development from ancient times to date are described. How the chemical composition of these products changed with time, how new ideas revealing the physical and chemical basics of external media that influence the mechanical processing of materials appeared, how these ideas explained the differences between traditional tribology and specific technology of metal processing are discussed. The question of the possible realization of Rehbinder＇s adsorption effect in contact zone is also stated. The description of a very captivating problem is related to the explanation of the mechanism of lubricant penetration into the contact zone between the material being processed and the tool. The birth and development of the hypothesis of microcapillary penetra- tion of the lubricant into the dynamically changed intersurface clearance that has finally led to formulating the ＂necessary kinetic condition of the lubricating activity＂ is relayed.

关键词： technological lubrication and cooling metal cutting grinding lubrication action tribology

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Effect of Y_2O_3 and Total Oxide Addition on Mechanical Properties of Pressureless Sintered β-SiC

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Journal of Materials Science & Technology 2003年第3期19卷 193-196页

作者： vladimir D.Krstic Centre for Manufacturing of Advanced Ceramics and Nanomaterials Queen’s UniversityNicol HallKingstonOntarioCanada K7L 3N6

The effect of Y203 and the total oxide volume fraction (Y203+Ai203) on density and mechanical properties of low temperature (1770-1940℃) pressureless sintered β-SiC ceramics were presented. The optimum temperature for pressureless sintering of β-SiC was found to be -1850℃ and the optimum content of Y203 in the oxides was found to be between 40 and 57 wt pct. The highest sintered density was achieved by adding oxides at 14 vol. pct. Both of the highest strength and fracture toughness were achieved at -14 vol. pct oxide addition and yttria concentrations between 40 and 57 wt pct in the oxides. Hardness, on the other hand, was found to be the highest for samples with 14 vol. pct oxide addition and -64 wt pct Y2O3 in oxides.

关键词： Y_2O_3 SiC Mechanical properties Sintering

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Elaboration of a conceptual solution for the development of the Arctic shelf from seasonally flooded coastal areas

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international Journal of Mining Science and Technology 2022年第1期32卷 113-119页

作者： vladimir S.Litvinenko Mikhail V.Dvoynikov vladimir L.Trushko Saint-Petersburg Mining University Saint-Petersburg 199106Russia

Currently,construction of facilities in the Arctic is carried out on sand islands,but there are limitations for remote coastal *** restrictions are associated with the lack of quarries with construction sand in the immediate vicinity of the work site,as well as the risk of seasonal flooding of the *** article includes conceptual solutions for construction of modular piling in Arctic nearshore conditions,upon which drilling rigs and auxiliary equipment can be placed for the purpose of subsequent wildcatting,development and exploratory extended reach drilling wells(with measured depth about 15000 m).During the construction of the modular piling foundations,a mathematical simulation of the thermodynamic condition of the frozen ground was conducted,and the bearing capacity of the foundations was *** proposed solutions will solve these problems by constructing modular pile foundations and placing the necessary infrastructure on them,taking into account the distribution of loads during operation in seasonally flooded areas.

关键词： Drilling&drillholes Stress analysis Offshore engineering infrastructure planning Geotechnical engineering Extended reach drilling

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A theory to link relationships of stand volume,density,mean diameter and height in forestry data

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Journal of Forestry Research 2021年第1期32卷 15-20页

作者： vladimir L.Gavrikov Chair of Ecology and Environmental Studies Institute Ecology and GeographySiberian Federal University79 pr.SvobodnyiKrasnoyarskRussian Federation 660041

in this study,a geometric model of a growing forest stand has been *** basic relationships considered link stand volume and stand density,diameter at breast height(DBH),mean DBH and mean *** model provides simple formulas connecting the exponents of all the *** of the formulas to real forestry data provided a high level of predictions of an exponent from two others measured through regressions from empirical *** Pinus sylvestris *** were of a static nature,a collection of individual stands,while the Pseudotsuga menziesii(Mirb.)Franco data were dynamic,representing forest stand development over *** ability of the model to predict exponents in the empirical data implies,on the one hand,a substantial level of similarity between the model and the forestry ***,on the other hand,the model gives an example in which parameters of one relationship may be linked to parameters of *** this kind of‘relationship between relationships’may be observed in forest stands undergoing active growth and competition-induced self-thinning.

关键词： Relationship between relationships Selfthinning Forestry data Allometry Scots pine Douglasfir

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Equilibrium Arrivals to Preemptive Queueing System with Fixed and Random Population Size

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Journal of the Operations Research Society of China 2024年第1期12卷 77-92页

作者： Julia Chirkova vladimir Mazalov institute of Applied Mathematical Research Karelian Research Centre of RASPetrozavodsk185910Russia School of Mathematics and Statistics Qingdao UniversityQingdao266071ShandongChina

A single-server queueing system with preemptive access is *** customer has one attempt to enter the system at its working interval[0,T].As soon as the customer request enters the system,the server immediately starts the *** when the next request arrives in the system,the previous one leaves the system even he has not finished his service *** study a non-cooperative game in which the customers wish to maximize their probability of obtaining service within a certain period of *** characterize the Nash equilibrium and the price of anarchy,which is defined as the ratio between the optimal and equilibrium social *** models are *** the first model the number of players is fixed,while in the second it is random and obeys the Poisson *** demonstrate that there exists a unique symmetric equilibrium for both ***,we calculate the price of anarchy for both models and show that the price of anarchy is not monotone with respect to the number of customers.

关键词： Service system Preemptive priorities Strategic users Random number of players Optimal arrivals Kolmogorov backward equations Nash equilibrium Price of anarchy

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Sedimentation History of Neogene Lacustrine Sediments of Sueoka Bela Stena Based on Geochemical Parameters(Valjevo-Mionica Basin,Serbia)

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Acta Geologica Sinica(English Edition) 2008年第6期82卷 1201-1212页

作者： Aleksandra AJNOVi vladimir SiMi Branimir JOVANiEVi Olga CVETKOVi Radovan DiMiTRiJEVi Nenad GRUBiN Center of Chemistry IChTM11000 BelgradeSerbia Faculty of Mining and Geology University of Belgrade11000 BelgradeSerbia Faculty of Chemistry University of Belgrade11000 BelgradeSerbia Rio Tinto Exploration Bulevar A VNOJ-a 7111000 BelgradeSerbia

Sediments of the western part of the Valjevo-Mionica basin （Serbia） were examined both geochemically and mineralogically to explain, on the basis of their sedimentologicai characteristics, the causes of changes in their qualitative and quantitative composition. A total of 62 samples obtained from the drillhole at depths up to 400 m was investigated. Using correlation of the obtained data, six geochemical zones were defined, two of which being specially distinguished by their mineralogical, geochemical and sedimentological characteristics. The first one, upper zone A, consists of banded marlstones interbedded with clay and oil shales and is characterized by presence of analcite and searlesite. These minerals and very high contents of Na20 indicate sedimentation in alkaline conditions with increased salinity in arid climate. That provided pronounced water stratification, as well as higher bioproductivity in the basin and sedimentary organic matter preservation. Therefore, the zone A sediments are characterized by high organic matter contents of the type which provides good potential for production of liquid hydrocarbons. Another specific zone, zone F, contains sediments with very high MgO, K2O and Li concentrations. Their geochemical correlation, as well as almost complete absence of illite in this zone, indicates the presence of interstratified clay mineral type illite-saponite （lithium-bearing Mg-smectite）.

关键词： lacustrine sediments geochemistry searlesite statistical analysis

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Real-time decay of fluorinated fullerene molecules on Cu（001） surface controlled by initial coverage

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Nano Research 2018年第4期11卷 2069-2082页

作者： Andrey i. Oreshkin Dmitry A. Muzychenko Sergey i. Oreshkin vladimir A. Yakovlev Palanichamy Murugan S. Selva Chandrasekaran Vijay Kumar Rauf Z. Bakhtizin Department of Physics Lomonosov Moscow State University 119991 Moscow Russia Sternberg Astronomical institute Lomonosov Moscow State University 119234 Moscow Russia institute of Petrochemical Synthesis Russian Academy of Sciences 119991 Moscow Russia CSiR Central Electrochemical Research institute Karaikudi 630003 Tamil Nadu India Dr. Vijay Kumar Foundation 1969 Sector 4 Gurgaon 122001 Haryana India Center for informatics School of Natural Sciences Shiv Nadar University NH91 Tehsil Dadari Gautam Budh Nagar 201314 Uttar Pradesh India Department of Physical Electronics Bashkir State University 450074 Ufa Russia

in this study, the evolution of C60F18 molecules on a Cu（001） surface was studied by means of scanning tunneling microscopy and density functional theory calculations. The results showed that fluorinated fuUerenes （tortoise-shaped polar C60F18） decay on Cu（001） surfaces by a step-by-step detachment of F atoms from the C60 cage. The most favorable adsorption configuration was realized when the F atoms of C60F18 pointed towards the Cu surface and six F atoms were detached from it. The results also showed that a further decay of C60F12 molecules strongly depended on the initial C60F18 coverage. The detached F atoms initially formed a two-dimensional （2D） gas phase which then slowly transformed into F-induced surface structures. The degree of contact between the C60F12 molecules and the Cu（001） surface depended on the density of the 2D gas phase. Hence, the life-time of fluorinated fullerenes was determined by the density of the 2D gas phase, which was affected by the formation of new F-induced structures and the decay of C60F12 molecules.

关键词： fluorinated fullerene (001) Cu surface two-dimensional (2D)molecular island 2D gas phase self-assembling molecules scanning tunneling microscopy (STM) density functional theory(DFT)

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