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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

SIMULATION MODEL OF TECHNOLOGICAL MINERAL DRESSING PROCESSES

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International Journal of Modeling, Simulation, and Scientific Computing 2012年第3期3卷 36-42页

作者： NGUYEN vAN CHI A.v.petrov Department of Automated Systems Irkutsk State Technical University Lermontova 83 Irkutsk664074Russian Federation

The authors worked out a simulation model of technological mineral dressing processes,in which two simulations of technological mineral dressing processes methods are used:transformed structural graph method and method of separation *** first method makes it possible to simulate technological mineral dressing processes at the design stage in conditions of feedstock,equipment and control information *** second method is an effective instrument for operating plant simulation at the reengineering *** and economic efficiency evaluations of the mineral dressing plant are appended to the model.

关键词： Simulation mineral dressing structural graph separation characteristics reengineering efficiency

Magnetic and XPS studies of lithium lanthanide tetraphosphates LiLnP_4O_(12)(Ln=Nd,Gd,Er)

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Journal of Rare Earths 2013年第5期31卷 485-489页

作者： D.petrov B.Angelov v.Lovchinov Department of Physical Chemistry Plovdiv University"Paisii Hilendarski" 24 Tsar Asen Str. 4000 Plovdiv Bulgaria Department of Inorganic and Physical Chemistry University of Food Technologies-Plovdiv26 Maritsa Blvd. 4002 Plovdiv Bulgaria Institute of Solid State Physics Bulgarian Academy of Sciences72Tsarigradsko Chaussee Blvd.1784 SofiaBulgaria

Magnetic susceptibilities of flux-grown single crystals of LitnP4012 （Ln=Nd, Gd, Er） were measured in the temperature range of 2-300 K. The compounds were paramagnetic, and obeyed the Curie-Weiss law in the entire temperature interval, without magnetic phase transitions, and with effective magnetic moments close to those of the corresponding free Ln3＋ ions. X-ray photoelec- tron spectroscopy was applied to determine the positions of core-level electrons relative to the Fermi level： Li is; Ln 4f, 5p, 5s, 4d, 3d; P 2s, 2p; O 1s, 2s. The binding energies in these compounds were found slightly shifted compared to the respective values of the same elements.

关键词： lithium lanthanide tetraphosphates single crystals magnetic properties XPS spectroscopy rare earths

Energy of a solid sphere under nonstationary oscillations

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 469-476页

作者： petrov Yu. SMIRNOv v. UTKIN A. BRATOv v. St.-Petersburg State University Institute of Problems of Mechanical Engineering Russian Academy of Sciences St.-Petersburg State Transport University

Analytical solution for spherically symmetric nonstationary oscillations of acoustic and elastic solid sphere is *** dependence of potential,kinetic and internal energy of a solid sphere is *** received results are of practical importance for a wide range of problems connected to testing of material dynamic strength parameters and to the problems of optimizing(minimizing)energy needed for fracture of solids.

关键词： nonstationary oscillations analytical solution material dynamics dynamic elastisity kinetic energy potential energy internal energy energy exchange

Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs víctor Cilleros-Mañé Laia Just-Borràs Marta Balanyà-Segura Aleksandra Polishchuk Laura Nadal Marta Tomàs Carolina Silvera-Simón Manel M.Santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

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

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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

Ambiguity of Polystyrene Aerosol Beads Properties Found with Mie Spectra Analysis

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光谱学与光谱分析 2020年第1期40卷 324-327页

作者： petrov D v Zhuzhulina E A Crimean Astrophysical Observatory(CrAO RAS)

Broadband Mie scattering is used to determine the parameters of polystyrene aerosol beads in air,such as size and wavelength dependence of refractive *** method consists in the selection of such parameters of the scattering object,which reproduce observed spectrum *** is why it is very sensitive and hence very *** found that there is an ambiguity of polystyrene aerosol beads properties,determined with this *** combinations of polystyrene particle size and its refractive index can give the same position of Mie *** ambiguity leads to an increase in the error in determining the size and refractive index of the *** refined errors are calculated and the way of their reduction is indicated.

关键词： Nanomaterials Mie theory Polystyrene beads Size Refractive index

Spectral Dependence of Quasi-Rayleigh Polarization Leap of Nonspherical Particles:Polystyrene Beads Application

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光谱学与光谱分析 2021年第2期41卷 654-657页

作者： petrov D v Zhuzhulina E A Crimean Astrophysical Observatory(CrAO RAS) 298409 Nauch nyjRussia

Solid particles in Earth’s atmosphere,such as polystyrene beads,are an important factor affecting the processes of absorption and scattering of light in the *** processes affect on the solar energy transfer in the Earth’s atmosphere,consequently they have influence on the regional and global climate changes and atmospheric *** particular,great interest to study the scattering properties of small particles compared with wavelength,because of such particles experience low gravitational settlement and may have long time of life in the *** scattering particle is much smaller than the wavelength of the scattered or absorbed light,this is the case of Rayleigh *** properties of these particles(such as intensity and the degree of linear polarization)at the Rayleigh scattering are simply derived from electromagnetic Maxwell’s *** when the particles are large enough to be comparable with the wavelength,the deviations from Rayleigh scattering law are *** of the clear manifestations of such deviations is the recently discovered quasi-Rayleigh polarization leap of monodisperse spherical *** quasi-Rayleigh polarization leap allows remote sensing of the sizes of distant particles,based on the spectral position of quasi-Rayleigh polarization leap at different phase angles of *** this paper,we studied the effect of the non-sphericity of a scattering polystyrene particle on the magnitude and position of the quasi-Rayleigh polarization *** is established that the non-sphericity shifts the position of the quasi-Rayleigh polarization leap shorter *** is shown that for non-sphericity of particles makes the quasi-Rayleigh polarization leap becomes less ***,it was found,that increasing of the phase angle and degree of non-sphericity shift the quasi-Rayleigh polarization leap position to shorter ***,in the case of not very elongated particles,the quasi-

关键词： Nanomaterials Polarization T-matrix Quasi-Rayleigh polarization leap

Methods for recording the time profile of single ultrashort pulses of electron beams and discharge currents in real-time mode

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High voltage 2016年第1期1卷 43-51页

作者： victor F.Tarasenko Dmitry v.Rybka Institute of High Current Electronics Siberian Branch Russian Academy of SciencesTomsk 634055Russia

The collectors for measuring the time profile of a current pulse of the runaway electron beam that are generatedunder atmospheric pressure are described. An analysis of changes in pulse shape depending on the bandwidth of theregistration path with a temporal resolution of up to 20 ps was performed. It is shown that the electron beam detectedbehind small-diameter diaphragms has a complex structure, which depends on the parameters of the gas diode. Thereis a design of the current shunts with a temporal resolution of up to 100 ps in this study. Measurement techniques ofvoltage pulses with subnanosecond and nanosecond duration are briefly described.

关键词： ultrashort pulse recording