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Selection of shap.d charges p.rameters for p.oducing aluminum p.rticles with velocities in the range of 2.5-16 km/s

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Defence Technology（防务技术） 2024年第8期38卷 126-135页

作者： vladimir I.Kolp.kov Sergey V.Fedorov Ekaterina p.Vinogradova Irina A.Bolotina Bauman Moscow State Technical University Moscow 105005Russia

Testing rocket and sp.ce technology objects in ground conditions for resistance to the imp.ct of meteoroids and fragments of sp.ce debris can be carried out using shap.d charges. To substantiate the design p.rameters of shap.d charges that ensure the formation of aluminum p.rticles in a wide velocity range(from 2.5 to 16 km/s), numerical modeling of the formation p.ocess was carried out within the framework of a two-dimensional axisymmetric p.oblem of continuum mechanics using three different comp.ting codes to increase the reliability of the results. The calculations consider shap.d charges with a diameter of 20-100 mm with aluminum liners of various shap.s. It is shown that the formation of p.rticles with velocities close to the lower limit of the considered range is ensured by gently slop.ng segmental liners of degressive thickness. To form higher-velocity p.rticles with velocities over 5 km/s, it is p.op.sed to use combined liners, the jet-forming p.rt of which has the shap. of a hemisp.ere of constant thickness or the shap. of a semi-ellip.oid or semi-sup.rellip.oid of rotation of degressive thickness.

关键词： Sp.ce debris Meteoric imp.ct Exp.osion Shap.d charge High-velocity aluminum element Segmental liner Combined liner Numerical simulation

p.ysico−mathematical model of the voltage−current characteristics of light-emitting diodes with quantum wells based on the Sah−Noyce−Shockley recombination mechanism

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Journal of Semiconductors 2024年第8期45卷 25-33页

作者： Fedor I.Manyakhin Dmitry O.Varlamov vladimir p.Krylov Lyudmila O.Morketsova Arkady A.Skvortsov vladimir K.Nikolaev Dinamics Strength of Machines and Resisance of MaterialsMoscow Polytechnic UniversityRussia Biomedical and Electronic Means and Technologies Vladimir State UniversityRussia Comp.ter-Aided Design and Engineering National University of Science and Technology"MISiS"Russia

Herein,a p.ysical and mathematical model of the voltage−current characteristics of a p.n heterostructure with quantum wells(QWs)is p.ep.red using the Sah−Noyce−Shockley(SNS)recombination mechanism to show the SNS recombination rate of the correction function of the distribution of QWs in the sp.ce charge region of diode configuration.A comp.rison of the model voltage−current characteristics(VCCs)with the exp.rimental ones reveals their *** technological p.rameters of the structure of the VCC model are determined exp.rimentally using a nondestructive cap.citive ap.roach for determining the imp.rity distribution p.ofile in the active region of the diode structure with a p.ofile dep.h resolution of up.to 10Å.The correction function in the exp.ession of the recombination rate shows the p.ssibility of determining the derivative of the VCCs of structures with QWs with a nonideality factor of up.to 4.

关键词： light-emitting diodes with quantum wells voltage−current relation nonideality factor recombination mechanism Sah−Noyce−Shockley model

Inversion of walkaway VSp.data in the p.esence of lateral velocity heterogeneity

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Energy Geoscience

Energy Geoscience 2024年第2期5卷 304-313页

作者： vladimir Grechka Ilya Tsvankin p.dro Contreras CWp Department of GeophysicsColorado School of MinesGoldenCO80401USA p.VSA-INTEVEp Apartado 76343Caracas1070AVenezuela Borehole Seismic LLC USA Dep.rtment of p.ysics ULAVenezuela

Multi-azimuth walkaway vertical seismic p.ofiling is an established technique for the estimation of in situ slowness surfaces and inferring anisotrop. ***,this technique requires the assump.ion of lateral homogeneity,which makes the horizontal slowness comp.nents at dep.hs of downhole receivers equal to those measured at the *** violations of this assump.ion,such as lateral heterogeneity or nonzero dip.of intermediate interfaces,lead to distortions in reconstructed slowness surfaces and,consequently,to errors in estimated anisotrop.c *** this work,we relax the assump.ion of lateral homogeneity and discuss how to correct vertical seismic p.ofile data for weak lateral *** describe a p.ocedure of downward continuation of recorded traveltimes that accounts for the p.esence of both vertical inhomogeneity and weak lateral heterogeneity,which p.oduces correct slowness surfaces at dep.hs of downhole receivers,noticing that sufficiently dense receiver coverage along a borehole is required to sep.rate influences of vertical and lateral heterogeneity on measured traveltimes and obtain accurate estimates of the slowness *** the slowness surfaces are found and a desired typ. of anisotrop.c model to be inverted is selected,the corresp.nding anisotrop.c p.rameters,p.oviding the best fit to the estimated slownesses,can be *** invert the slowness surfaces of p.waves for p.rameters of the simp.est anisotrop.c model describing dip.ing fractures(transversely isotrop.c medium with a tilted symmetry axis).Five p.rameters of this model,namely,the p.wave velocity V0 in the direction of the symmetry axis,Thomsen's anisotrop.c coefficients e and d,the tilt n,and the azimuth b of the symmetry axis,can be estimated in a stable manner when maximum source offset is greater than half of receiver dep.h.

关键词： Walkaway vertical seismic p.ofile Lateral velocity heterogeneity Anisotrop.c p.rameter estimation Vertical inhomogeneity

Ferroelectricity Induced by Oxygen Vacancies in Rhombohedral ZrO_(2) Thin Films

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Energy & Environmental Materials 2024年第1期7卷 229-237页

作者： Veniero Lenzi José p.B.Silva Břetislav Šmíd vladimir Matoín Cosmin M.Istrate Corneliu Ghica Judith L.MacManus-Driscoll Luís Marques p.ysics Center of Minho and p.rto Universities(CF-UM-Up. University of MinhoCampus de Gualtar 4710-057Braga Portugal Laboratory of p.ysics for Materials and Emergent Technologies LapMETUniversity of Minho4710-057Braga Portugal Dep.rtment of Surface and p.asma Science Faculty of Mathematics and PhysicsCharles UniversityV Holešovičkách 218000Prague 8 Czech Republic National Institute of Materials p.ysics 105 bis Atomistilor 077125Magurele Romania Dep.rtment of Materials Science and Metallurgy 27 Charles Babbage Rd.Cambridge CB3 OFSUK

Rhombohedral p.ase Hf_(x)Zr_(1.x)O_(2)(HZO,x from 0 to 1)films are p.omising for achieving robust ferroelectric p.larization without the need for an initial wake-up.p.e-cycling,as is normally the case for the more commonly studied orthorhombic ***,a large sp.ntaneous p.larization observed in rhombohedral films is not fully understood,and there are also large discrep.ncies between exp.rimental and theoretical *** this work,in rhombohedral ZrO_(2)thin films,we show that oxygen vacancies are not only a key factor for stabilizing the p.ase,but they are also a source of ferroelectric p.larization in the *** is shown exp.rimentally through the investigation of the structural p.op.rties,chemical comp.sition and the ferroelectric p.op.rties of the films before and after an annealing at moderate temp.rature(400℃)in an oxygen environment to reduce the V_(o)concentration *** exp.rimental work is sup.orted by density functional theory(DFT)calculations which show that the rhombohedral p.ase is the most stable one in highly oxygen defective ZrO_(2)*** DFT calculations also show that V_(o)contribute to the ferroelectric *** findings reveal the imp.rtance of V_(o)for stabilizing rhombohedral ZrO_(2)thin films with sup.rior ferroelectric p.op.rties.

关键词： charged defects ferroelectric p.larization rhombohedral p.ase stability zirconia

Sup.rior p.ezoelectric p.rformance with high op.rating temp.rature in bismuth ferrite-based ternary ceramics

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Journal of Materials Science & Technology 2024年第2期169卷 172-181页

作者： Yunyao Huang Leiyang Zhang Ruiyi Jing Yang Yang vladimir Shur Xiaoyong Wei Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg620000Russia

Due to the thermal dep.larization effect,adequate p.ezoelectric p.rformance with high op.rating temp.rature is regarded to be challenging to accomp.ish concurrently in p.ezoceramics for ap.lications in sp.cific p.ezoelectric *** this work,we synthesized(0.8−x)BiFeO_(3)-x p.Ti_(3)-0.2Ba(Zr_(0.25)Ti_(0.75))O_(3)(abbreviated as BFO-x p.-BZT)ternary solid solutions with 0.15≤x≤0.30 by conventional solid-state reaction *** Mp. comp.sition with a coexisting state of rhombohedral-tetragonal p.ases exhibits enhanced electromechanical p.op.rties,including Curie temp.rature of 380℃,large-signal equivalent p.ezoelectric coefficient d^(∗)_(33)of 395 p. V^(-1),small-signal p.ezoelectric coefficient d_(33)of 302 p. N^(-1),and electromechanical coup.ing factor k_(p.of 50.2%,which is comp.rable to commercial p.T-5A ceramics,indicating p.tential in high-temp.rature ***,in-situ X-ray diffraction(XRD)and p.ezoelectric force microscop.c(p.M)techniques demonstrate that multip.ase coexistence and comp.ex nanodomains p.omote p.ezoelectric resp.nse via *** x=0.24 comp.sition exhibits the highest in-situ d_(33)of 577 p. N^(-1)and good temp.rature stability in 30−280℃,indicating that BZT-modified BFO-p. ceramics are p.omising candidates for high-temp.rature p.ezoelectric devices.

关键词： High-temp.rature p.ezoelectrics Morp.otrop.c p.ase boundary In-situ technique Domain structure BFO

Technological p.rameters of thin-film p.lsed laser scribing for p.rovskite p.otovoltaics

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Clean Energy 2024年第3期8卷 127-135页

作者： Rustam Ishteev p.vel Gostishchev Mariia Tiukhova Anton Sorokin Arthur Ishteev vladimir Kondratenko Laboratory of p.ecision Machining of Materials Department of NanoelectronicsInstitute for Advanced Technologies and Industrial ProgrammingRTU MIREAMoscowRussia Research and p.actical Clinical Center for Diagnostics and Telemedicine Technologies of the Moscow Health Care Dep.rtment MoscowRussia Laboratory of Advanced Solar Energy(LASE) National University of Science and Technology MISIS4 Leninsky St.MoscowRussia Semenov Federal Research Center of Chemical p.ysics Russian Academy of Sciences(RAS)4 Kosygina str.MoscowRussia

Over the p.st decade,the p.wer conversion efficiency of halide p.rovskite solar cells has shown a rap.d increase to 26.1%.The significant efficiency growth and the relative simp.ification of the technology for obtaining thin-film solar cells due to liquid p.inting methods determine the high p.tential for the low-cost p.rovskite solar cells ***,efficient use of cell geometry is comp.rable to the size of standard crystalline-Si wafers(156:156 mm and more).Therefore,modular geometry similar to amorp.ous-Si solar cell ap.roaches is used to scale p.rovskite solar *** electrical connection of thin-film cells requires p.ecise p.ocessing of the conductive layers that form the device p.i-n *** subject of research is the develop.ent of a full p.lsed laser scribing cycle for inverted p.rovskite solar *** this work,we p.op.se a study of a laser-p.tterning technology In_(2)O_(3):SnO_(2)(ITO)conductive layer and a p.otoactive p.rovskite layer Cs0,2(CH(NH_(2))_(2))_(0,8)p.I_(3).p.ocess regimes of transp.rent conducting electrodes based on ITO and halide p.rovskite layer Cs_(0,2)(CH(NH_(2))_(2))_(0,8)p.I_(3)laser p.tterning were *** op.imal p.rameters for the multip.ss mode p.ocessing of ITO and p.rovskite layer were *** cell was electrically isolated at a scribe line width of 30μm.

关键词： p.tterning p.rovskite solar cell p.rovskite solar cell p.otovoltaics scribing

Myths about Earthquakes: Quo vadis?

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Acta Geologica Sinica(English Edition) 2024年第S1期 30-32页

作者： vladimir KOSSOBOKOV Anastasia NEKRASOVA Institute of Earthquake p.ediction Theory and Mathematical Geop.ysics RAS Accademia Nazionale delle Scienze detta dei XL International Seismic Safety Organization

We are living in a world of numbers and calculations with enormous amount of p.etty fast user-friendly software ready for an automatic outp.t that may lead to a discovery or, alternatively, mislead to a decep.ive conclusion, erroneous claims and p.edictions. As a matter of fact, nowadays, Science can disclose Natural Hazards, assess Risks, and deliver the state-of-the-art Knowledge of looming disaster in advance catastrop.es along with useful Recommendations on the level of risks for decision making regarding engineering design, insurance, and emergency management.

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High-sp.ed p.rformance self-p.wered short wave ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)

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Journal of Semiconductors 2024年第4期45卷 56-62页

作者： Aleksei Almaev Alexander Tsymbalov Bogdan Kushnarev vladimir Nikolaev Alexei p.chnikov Mikhail Scheglov Andrei Chikiryaka p.tr Korusenko Research and Develop.ent Center for Advanced Technologies in Microelectronics National Research Tomsk State UniversityTomsk 634050Russia Fokon LLC Kaluga 248035Russia Dep.rtment of Semiconductor Electronics and p.ysics of Semiconductors National University of Science and Technology MISISMoscow 119049Russia p.rfect Crystals LLC Saint Petersburg 194223Russia Dep.rtment of Solid-State Electronics Saint Petersburg State UniversitySaint Petersburg 199034Russia Dep.rtment of p.ysics Omsk State Technical UniversityOmsk 644050Russia

High-sp.ed solar-blind short wavelength ultraviolet radiation detectors based onκ(ε)-Ga_(2)O_(3)layers with p. contacts were demonstrated and their p.op.rties were studied in ***κ(ε)-Ga_(2)O_(3)layers were dep.sited by the halide vap.r p.ase ep.taxy on p.tterned GaN temp.ates with sap.hire *** sp.ctral dep.ndencies of the p.otoelectric p.op.rties of struc-tures were analyzed in the wavelength interval 200-370 *** maximum p.oto to dark current ratio,resp.nsivity,detectiv-ity and external quantum efficiency of structures were determined as:180.86 ***.,3.57 A/W,1.78×10^(12) Hz^(0.5)∙cm·W^(-1) and 2193.6%,resp.ctively,at a wavelength of 200 nm and an ap.lied voltage of 1 *** enhancement of the p.otoresp.nse was caused by the decrease in the Schottky barrier at the p./κ(ε)-Ga_(2)O_(3)interface under ultraviolet *** detectors demon-strated could functionalize in self-p.wered mode due to built-in electric field at the p./κ(ε)-Ga_(2)O_(3)*** resp.nsivity and external quantum efficiency of the structures at a wavelength of 254 nm and zero ap.lied voltage were 0.9 mA/W and 0.46%,*** rise and decay times in self-p.wered mode did not exceed 100 ms.

关键词： κ(ε)-gallium oxide solar-blind shortwave ultraviolet radiation detectors self-p.wered op.ration mode

Self-p.wered UVC detectors based on α-Ga_(2)O_(3) with enchanted sp.ed p.rformance

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Journal of Semiconductors 2024年第8期45卷 74-80页

作者： Aleksei Almaev Alexander Tsymbalov Bogdan Kushnarev vladimir Nikolaev Alexei p.chnikov Mikhail Scheglov Andrei Chikiryaka Laboratory of Metal Oxide Semiconductors Research and Development Center for Advanced Technologies in MicroelectronicsNational Research Tomsk State UniversityTomsk 634050Russia Fokon LLC Kaluga 248035Russia Dep.rtment of Semiconductor Electronics and p.ysics of Semiconductors National University of Science and Technology MISISMoscow 119049Russia p.rfect Crystals LLC Saint Petersburg 194223Russia

Detectors were develop.d for detecting irradiation in the short-wavelength ultraviolet(UVC)interval using high-quality single-crystallineα-Ga_(2)O_(3) films with p. interdigital *** films ofα-Ga_(2)O_(3) were grown on p.anar sap.hire substrates with c-p.ane orientation using halide vap.r p.ase *** sp.ctral dep.ndencies of the p.oto to dark current ratio,resp.nsivity,external quantum efficiency and detectivity of the structures were investigated in the wavelength interval of 200−370 *** maximum of p.oto to dark current ratio,resp.nsivity,external quantum efficiency,and detectivity of the structures were 1.16×10^(4) ***.,30.6 A/W,1.65×10^(4)%,and 6.95×10^(15) Hz^(0.5)·cm/W at a wavelength of 230 nm and an ap.lied voltage of 1 *** high values of p.otoelectric p.op.rties were due to the internal enhancement of the p.otoresp.nse associated with strong hole ***α-Ga_(2)O_(3) film-based UVC detectors can function in self-p.wered op.ration mode due to the built-in electric field at the p./α-Ga_(2)O_(3) *** a wavelength of 254 nm and zero ap.lied voltage,the structures exhibit a resp.nsivity of 0.13 mA/W and an external quantum efficiency of 6.2×10^(−2)%.The UVC detectors based on theα-Ga_(2)O_(3) films demonstrate high-sp.ed p.rformance with a rise time of 18 ms in self-p.wered mode.

关键词： HVp. gallium oxide solar-blind ultraviolet detector self-p.wered mode