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Autonomous UAv 3D trajectory optimization and transmission scheduling for sensor data collection on uneven terrains

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Defence Technology（防务技术） 2023年第12期30卷 154-160页

作者： andrey v.Savkin Satish C.verma Wei ni School of Electrical Engineering and Telecommunications University of New South WalesSydneyAustralia Data61 CSIROCanberraACT2601Australia

This paper considers a time-constrained data collection problem from a network of ground sensors located on uneven terrain by an Unmanned Aerial vehicle(UAv),a typical Unmanned Aerial System(UAS).The ground sensors harvest renewable energy and are equipped with batteries and data *** ground sensor model takes into account sensor data buffer and battery *** asymptotically globally optimal method of joint UAv 3D trajectory optimization and data transmission schedule is *** developed method maximizes the amount of data transmitted to the UAv without losses and too long delays and minimizes the propulsion energy of the *** developed algorithm of optimal trajectory optimization and transmission scheduling is based on dynamic *** simulations demonstrate the effectiveness of the proposed algorithm.

关键词： Unmanned aerial system UAS Unmanned aerial vehicle UAv Wireless sensor networks UAS-Assisted data collection 3D trajectory optimization Data transmission scheduling

Energy-efficient joint UAv secure communication and 3D trajectory optimization assisted by reconfigurable intelligent surfaces in the presence of eavesdroppers

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Defence Technology（防务技术） 2024年第1期31卷 537-543页

作者： Huang Hailong Mohsen Eskandari andrey v.Savkin Wei ni The Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Electrical Engineering and Telecommunications University of New South WalesSydney2052Australia Data61 CSIROAustralia

We consider a scenario where an unmanned aerial vehicle(UAv),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple *** friendly reconfigurable intelligent surfaces(RISs) help to secure the UAv-target communication and improve the energy efficiency of the *** formulate an optimization problem to minimize the energy consumption of the UAv,subject to the mobility constraint of the UAv and that the achievable secrecy rate at the target is over a given *** present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAv and the configurations of the *** effectiveness of the proposed method is validated via computer simulations.

关键词： Unmanned aerial systems(UASs) Unmanned aerial vehicle(UAv) Communication security Eaves-dropping Reconfigurable intelligent surfaces(RIS) Autonomous navigation and placement Path planning Model predictive control

Enhanced nonlinear instabilities in photonic circuits with exceptional point degeneracies

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Photonics Research 2020年第5期8卷 737-744页

作者： SUWUn SUWUnnARAT rodion KOnOnCHUK andrey CHABAnOv ILYA vITEBSKIY nICHOLAOS I.LIMBEROPOULOS TSAMPIKOS KOTTOS Department of Physics Wesleyan UniversityConnecticut 06459USA Department of Physics and Astronomy University of Texas at San AntonioSan AntonioTexas 78249USA Air Force Research Laboratory Sensors DirectorateWright-Patterson Air Force BaseOhio 45433USA

We propose a conceptual design of optical power limiters with abrupt limiting action and enhanced powerhandling capabilities that is based on exceptional point degeneracies(EPDs).The photonic circuit consists of two coupled cavities with differential Q *** of the cavities includes a Kerr-like nonlinear *** underlying mechanism that triggers an abrupt transmittance suppression relies on the interplay between a nonlinear instability and an abrupt destruction of EPDs due to a resonance detuning occurring when the incident power exceeds a critical *** proposal opens up possibilities for the use of EPDs in optical power switching,Q switching,routing,and so on.

关键词： material. value. exceptional

Juvenile survival curves in a solitary ground squirrel with a prolonged hibernation:effects of individual characteristics,environment,and maternal investment

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Current Zoology 2024年第1期70卷 13-23页

作者： nina A.vasilieva Liudmila E Savinetskaya andrey v.Tchabovsky A.n.Severtsov Institute of Ecology and Evolution Russian Academy of SciencesMoscow 119071Russia

Juvenile survival is a key life-history influence on population dynamics and adaptive *** analyzed the effects of individual chara-cteristics,early environment,and maternal investment on juvenile survival in a large solitary hibernating rodent-yellow ground squirrel Spermophilus fulvus using Cox mixed-effects *** 48%of weaned pups survived to dispersal and 17%survived to *** life expectancy was primarily determined by individual characteristics and,to a lesser extent,by the early *** strongest and pos-itive predictor of juvenile survival was body mass which crucially affected mortality immediately after *** suffered higher mortality than females after the onset of dispersal;however,the overall difference between sexes was partly masked by high rates of mortality in the first days after emergence in both *** emerged juveniles had lower life expectancy than the earliest *** overall effect of local juvenile density was *** lactation did not enhance juvenile survival:Pups nursed longer survived shorter than the young nursed for a shorter *** findings support the hypothesis that females of *** cannot effectively regulate maternal expenditures to mitigate the effects of unfavorable conditions on their *** strategy to deal with seasonal time constraints on life history in female *** suggests an early termination of maternal care at the cost of juvenile quality and *** female reproductive strategy corresponds to a"fast-solitary"life of folivorous desert-dwelling *** and other solitary ground squirrels with prolonged hibernation.

关键词： early-life conditions ground squirrels hibernation juvenile mortality maternal investment survival curves

Age of maturation and behavioral tactics in male yellow ground squirrel Spermophilus fulvus during mating season

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Current Zoology 2014年第6期60卷 700-711页

作者： nina A. vASILIEvA Ekaterina v. PAvLOvA Sergey v. nAIDEnKO andrey v.TCHABOvSKY A.n. Severtsov Institute of Ecology and Evolution Russian Academy of Sciences 33 Leninsky pr. Moscow 119071 Russia

Life-history theory predicts that in hibemators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics：＂active＂ males （adults only） emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than ＂passive＂ males （both yearling and adult）. Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

关键词： Age of maturation Mating system Reproductive tactics Ground squirrel Spermophilusfulvus

Operating limits and features of direct air capture on K_(2)CO_(3)/ZrO_(2) composite sorbent

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Chinese Journal of Chemical Engineering 2022年第6期35卷 11-20页

作者： vladimir S.Derevschikov Janna v.veselovskaya Anton S.Shalygin Dmitry A.Yatsenko andrey Z.Sheshkovas Oleg n.Martyanov Boreskov Institute of Catalysis SB RAS Akademika Lavrentieva Av.5630090 NovosibirskRussia novosibirsk State University Pirogova Str.1630090 NovosibirskRussia

Potassium carbonate-based sorbents are prospective materials for direct air capture(DAC).In the present study,we examined and revealed the influence of the temperature swing adsorption(TSA)cycle conditions on the CO_(2) sorption properties of a novel aerogel-based K_(2)CO_(3)/ZrO_(2) sorbent in a DAC *** was shown that the humidity and temperature drastically affect the sorption dynamic and sorption capacity of the *** a temperature at the sorption stage was 29℃ and a water vapor pressure P_(H2O) in the feed air was 5.2 mbar(1 bar=105 Pa),the composite material demonstrated a stable CO_(2) sorption capacity of 3.4%(mass).An increase in sorption temperature leads to a continuous decrease in the CO_(2) absorption capacity reaching a value of 0.7%(mass)at T=80℃.The material showed the retention of a stable CO_(2) sorption capacity for many cycles at each temperature in the *** PH2O in the inlet air from 5.2 to 6.8 mbar leads to instability of CO_(2) sorption capacity which decreases in the course of 3 consecutive TSA cycles from 1.7%to 0.8%(mass)at T=29℃.A further increase in air humidity only facilitates the deterioration of the CO_(2) sorption capacity of the material.A possible explanation for this phenomenon could be the filling of the porous system of the sorbent with solid reaction products and an aqueous solution of potassium salts,which leads to a significant slowdown in the CO_(2) diffusion in the composite sorbent *** investigate the regeneration step of the TSA cycle in situ,the macro ATRFTIR(attenuated total reflection Fourier-transform infrared)spectroscopic imaging was applied for the first *** was shown that the migration of carbonate-containing species over the surface of sorbent occurs during the thermal regeneration stage of the TSA *** movement of the active component in the porous matrix of the sorbent can affect the sorption characteristics of the composite *** revealed features make it possible

关键词： Zirconia aerogel Potassium carbonate Carbon dioxide Direct air capture Fourier-transform infrared spectroscopic imaging

CaAl_(2)Si_(2)O_(8) polymorphs:Sensitive geothermometers and geospeedometers

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Geoscience Frontiers 2023年第1期14卷 33-45页

作者： Liudmila A.Gorelova Oleg S.vereshchagin vladimir n.Bocharov Sergey v.Krivovichev andrey A.Zolotarev Mikhail A.Rassomakhin Institute of Earth Sciences Saint Petersburg State UniversitySt.PetersburgRussia Centrefor Geo-Environmental Research and Modelling(Geomodel).Saint Petersburg State University St.PetersburgRussia Kola Science Centre ApatityMurmansk RegionRussia South Urals Federal Research Center of Mineralogy and Geoecology of UB RAS MiassRussia

Plagioclase is the major rock-forming mineral constituting the Earth's crust,whereas anorthite(CaAl_(2)Si_(2)O_(8))is a common minerals in lunar highlands crust,meteorites,possibly in some comets and on *** anorthite,two high-temperature polymorphs of CaAl_(2)Si_(2)O_(8)are known:dmisteinbergite and svyatoslavite,which are found in burnt coal dumps,meteorites and *** we present the results of detailed studies(quenching experiments,elemental analysis,Raman spectroscopy and in situ high temperature single crystal X-ray diffraction(up to 1000℃))on naturally co-occurring CaAl_(2)Si_(2)O_(8)polymorphs(anorthite,dmisteinbergite and svyatoslavite)from a burnt coal dump in Kopeisk,*** polymorphs were found in all natural samples and obtained upon heating of dmisteinbergite(unquenchableβ-dmisteinbergite and quenchable y-dmisteinbergite).It was shown that Ca coordination differs significantly in CaAl_(2)Si_(2)O_(8)polymorphs,resulting in a different capacity to host Ba and possibly other large ion lithophile *** our data on natural samples with the previously published data on natural and synthetic compounds,we propose a new scheme of CaAl_(2)Si_(2)O_(8)polymorphs *** results indicate that CaAl_(2)Si_(2)O_(8)polymorphs could be used for temperature estimations for both Earth and planetary sciences.

关键词： Feldspar Polymorphism Anorthite Dmisteinbergite Svyatoslavite CaAl_(2)Si_(2)O_(8)

Submonolayer Eu superstructures—A class of 2D magnets

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nano Research 2023年第1期16卷 1500-1506页

作者： Dmitry v.Averyanov Ivan S.Sokolov Alexander n.Taldenkov Oleg E.Parfenov andrey M.Tokmachev vyacheslav G.Storchak national Research Center“Kurchatov Institute” Kurchatov Sq.1Moscow 123182Russia

Two-dimensional(2D)magnetic materials promise unconventional properties and quantum phases as well as advances in ultracompact *** of 2D magnets often reaches a single monolayer but in general can go beyond this limit,as demonstrated by 2D magnetism of submonolayer Eu superstructures coupled with *** question is whether the submonolayer magnetism constitutes a general ***,we demonstrate that regular Eu lattices form a class of 2D magnets displaying various structures,stoichiometries,and chemical *** synthesized and studied a set of Eu superstructures on Ge(001).Their magnetic properties are consistent with the emergence of a magnetic order such as ferro-or *** particular,control over the magnetic transition temperature by weak magnetic fields indicates the 2D nature of the *** together,Eu/Ge and Eu/Si superstructures seed a nucleus of the research area addressing the emergence of magnetism in submonolayer chemical species.

关键词： two-dimensional(2D)magnetism submonolayer superstructure surface reconstruction germanium

Efficient passivation of DY center in CH_(3)nH_(3)PbBr_(3) by chlorine:Quantum molecular dynamics

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nano Research 2022年第3期15卷 2112-2122页

作者： Ran Shi Wei-Hai Fang andrey S.vasenko Run Long Oleg v.Prezhdo College of Chemistry Key Laboratory of Theoretical&Computational Photochemistry of Ministry of EducationBeijing Normal UniversityBeijing 100875China national Research University Higher School of Economics(HSE)University 101000 MoscowRussia Donostia International Physics Center(DIPC) Paseo Manuel de Lardizabal 4San Sebastián/Donostia20018 Basque CountrySpain Department of Chemistry University of Southern CaliforniaLos AngelesCA 90089USA

MAPbBr_(3)(MA=CH_(3)nH_(3)^(+))doping with bismuth increases electric conductivity,charge carrier density and photostability,reduces toxicity,and expands light ***,Bi doping shortens excited-state lifetimes due to formation of DY−charge recombination *** nonadiabatic molecular dynamics and time-domain density functional theory,we demonstrate that the DY−center forms a deep,highly localized hole trap,which accelerates nonradiative relaxation ten-fold and is responsible for 90%of carrier *** trapping occurs by coupling between the valence band and the trap state,facilitated by the Br atoms surrounding the Bi *** of the DY−center with chlorines heals the local geometry distortion,eliminates the trap state,and makes the carrier lifetimes longer than even in pristine MAPbBr_(3).The decreased charge recombination arises from reduced nonadiabatic coupling and shortened coherence time,due to diminished electron–hole overlap around the passivated *** study demonstrates accelerated nonradiative recombination in Bi-doped MAPbBr_(3),suggests a strategy for defect passivation and reduction of nonradiative energy losses,and provides atomistic insights into unusual defect properties of metal halide perovskites needed for rational design of high-performance perovskite solar cells and optoelectronic devices.

关键词： Hybrid organic-inorganic perovskite DY−center and Cl passivation charge trapping and recombination nonadiabatic molecular dynamics time-domain density functional theory.