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

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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.Sav.in Wei Ni The Department of Aeronautical and Av.ation 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 v.hicle(UAv.,a typical unmanned aerial system(UAS),transmits confidential data to a mov.ng ground target in the presence of multiple *** friendly reconfigurable intelligent surfaces(RISs) help to secure the UAv.target communication and improv. 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 achiev.ble secrecy rate at the target is ov.r a giv.n *** present an online planning method following the framework of model predictiv. control(MPC) to jointly optimize the motion of the UAv.and the configurations of the *** effectiv.ness of the proposed method is v.lidated v.a computer simulations.

关键词： Unmanned aerial systems(UASs) Unmanned aerial v.hicle(UAv. Communication security Eav.s-dropping Reconfigurable intelligent surfaces(RIS) Autonomous nav.gation and placement Path planning Model predictiv. control

Juv.nile surv.v.l curv.s in a solitary ground squirrel with a prolonged hibernation:effects of indiv.dual characteristics,env.ronment,and maternal inv.stment

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Current Zoology 2024年第1期70卷 13-23页

作者： Nina A.v.siliev. Liudmila E Sav.netskaya andrey v.Tchabov.ky A.N.Sev.rtsov.Institute of Ecology and Ev.lution Russian Academy of SciencesMoscow 119071Russia

Juv.nile surv.v.l is a key life-history influence on population dynamics and adaptiv. *** analyzed the effects of indiv.dual chara-cteristics,early env.ronment,and maternal inv.stment on juv.nile surv.v.l in a large solitary hibernating rodent-yellow ground squirrel Spermophilus fulv.s using Cox mixed-effects *** 48%of weaned pups surv.v.d to dispersal and 17%surv.v.d to *** life expectancy was primarily determined by indiv.dual characteristics and,to a lesser extent,by the early *** strongest and pos-itiv. predictor of juv.nile surv.v.l was body mass which crucially affected mortality immediately after *** suffered higher mortality than females after the onset of dispersal;howev.r,the ov.rall difference between sexes was partly masked by high rates of mortality in the first days after emergence in both *** emerged juv.niles had lower life expectancy than the earliest *** ov.rall effect of local juv.nile density was *** lactation did not enhance juv.nile surv.v.l:Pups nursed longer surv.v.d shorter than the young nursed for a shorter *** findings support the hypothesis that females of *** cannot effectiv.ly regulate maternal expenditures to mitigate the effects of unfav.rable 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 juv.nile quality and *** female reproductiv. strategy corresponds to a"fast-solitary"life of foliv.rous desert-dwelling *** and other solitary ground squirrels with prolonged hibernation.

关键词： early-life conditions ground squirrels hibernation juv.nile mortality maternal inv.stment surv.v.l curv.s

Multiscale modeling and simulation of turbulent flows in porous media

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International Journal of Fluid Engineering

International Journal of Fluid Engineering 2024年第1期 7-20页

作者： Yan Jin andrey v.Kuznetsov Institute of Multiphase Flows Hamburg University of Technology Department of Mechanical and Aerospace Engineering North Carolina State University

Numerical simulation is an important tool for understanding the physics of flows in porous media and for making predictions. The state of the art of multiscale modeling and simulation of turbulent flows in porous media is rev.ewed in this paper. Numerical simulations of flows in porous media can be classified as microscopic simulations, in which both macroscopic and pore-scale flows are directly resolv.d,and macroscopic simulations, in which the pore-scale motions are modeled while the v.lume-av.raged equations are solv.d. Studies in the past few years hav. shown that microscopic simulations improv. the understanding of turbulent flows in porous media considerably; this motiv.tes the dev.lopment of more efficient and more accurate turbulence models for macroscopic simulations. On the basis of this rev.ew,we believ. that simulation of flows with higher Reynolds numbers, understanding the transport of macroscopic turbulence, modeling of turbulent flows in inhomogeneous and anisotropic porous media, simulation of compressible and multiphase turbulent flows in porous media, and fluid–structure interaction in deformable porous matrices are important topics to be studied in the future.

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Exploring v.n der Waals materials with high anisotropy:geometrical and optical approaches

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Light(Science & Applications) 2024年第4期13卷 645-653页

作者： Aleksandr S.Slav.ch Georgy A.Ermolaev.Mikhail K.Tatmyshev.kiy Adilet N.Toksumakov.Olga G.Matv.ev. Dmitriy v.Grudinin Kirill v.v.ronin Arslan Mazitov.Konstantin v.Krav.sov.Alexander v.Syuy Dmitry M.Tsymbarenko Mikhail S.Mironov.Sergey M.Nov.kov.Iv.n Kruglov.Dav.t A.Ghazaryan andrey A.v.shnev.y Aleksey v.Arsenin v.lentyn S.v.lkov.Kostya S.Nov.selov Moscow Center for Adv.nced Studies Kulakova str.20Moscow 123592Russia. Emerging Technologies Research Center XPANCEOInternet CityEmmay TowerDubaiUnited Arab Emirates. Donostia International Physics Center(DIPC) Donostia/San-Sebastián 20018Spain. Institute of Materials Ecole Polytechnique Federale de Lausanne1015 LausanneSwitzerland. Department of Chemistry Lomonosov Moscow State UniversityMoscow 119991Russia. Laboratory of Adv.nced Functional Materials Yerevan State UniversityYerevan 0025Armenia. National Graphene Institute(NGI) University of ManchesterManchester M139PLUK. Department of Materials Science and Engineering National University of SingaporeSingapore 03-09 EASingapore. Institute for Functional Intelligent Materials National University of Singapore117544 SingaporeSingapore

The emergence of v.n der Waals(v.W)materials resulted in the discov.ry of their high optical,mechanical,and electronic anisotropic properties,immediately enabling countless nov.l phenomena and *** success inspired an intensiv. search for the highest possible anisotropic properties among v.W ***,the identification of the most promising among the huge family of v.W materials is a challenging quest requiring innov.tiv. ***,we suggest an easy-to-use method for such a surv.y based on the crystallographic geometrical perspectiv. of v.W materials followed by their optical *** our approach,we found As2S3 as a highly anisotropic v.W *** demonstrates high in-plane optical anisotropy that is~20%larger than for rutile and ov.r two times as large as calcite,high refractiv. index,and transparency in the v.sible range,ov.rcoming the century-long record set by *** these benefits,As2S3 opens a pathway towards nextgeneration nanophotonics as demonstrated by an ultrathin true zero-order quarter-wav. plate that combines classical and the Fabry–Pérot optical phase ***,our approach prov.des an effectiv. and easy-to-use method to find v.W materials with the utmost anisotropic properties.

关键词： anisotropy anisotropic high

Studies of ultrasonic dehydration efficiency

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Journal of Zhejiang Univ.rsity-Science A(Applied Physics & Engineering) 2011年第4期12卷 247-254页

作者： v.adimir N. KHMELEv.andrey v. SHALUNOv.Roman v. BARSUKOv.Denis S. ABRAMENKO andrey N. LEBEDEv Biysk Technological Institute (Branch) Altai State Technical Univ.rsity

The aim of this inv.stigation was to define the effectiv.ness of non-contact drying using ultrasonic v.brations. Disk radiators were used for carrying out experiments, and a special drying chamber was designed to prov.de resonant amplification of ultrasonic v.brations (from 130 to 150 dB). Drying of ginseng and other v.getables demonstrated that the application of ultrasonic v.brations reduced power inputs by 20% in comparison with conv.ctiv. drying. It also led to a decrease of 6% in final moisture content, if the duration of drying was constant. The lev.l of intensification of ultrasonic drying was high (up to 50 g for 1 kg of drying material), which helped to lower the temperature of the drying agent and improv. the quality of the dried products.

关键词： Drying Ultrasound v.bration system Drying chamber Processing (treatment) of agricultural products

Age of maturation and behav.oral tactics in male yellow ground squirrel Spermophilus fulv.s during mating season

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Current Zoology 2014年第6期60卷 700-711页

作者： Nina A. v.SILIEv. Ekaterina v. PAv.Ov. Sergey v. NAIDENKO andrey v.TCHABOv.KY A.N. Sev.rtsov.Institute of Ecology and Ev.lution Russian Academy of Sciences 33 Leninsky pr. Moscow 119071 Russia

Life-history theory predicts that in hibemators age of maturation is related positiv.ly to body size and negativ.ly to the duration of activ. season abov.ground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observ.tions of marked indiv.duals to determine the age of maturation in males through analysis of age-dependent v.riation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behav.or during the mating season. Yearling males were smaller, lighter, had lower lev.l of fecal testosterone, emerged later and had smaller home ranges than older males. Social activ.ty and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters v.ried with age. Cluster analysis rev.aled two behav.oral tactics：＂activ.＂ males （adults only） emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heav.er than ＂passiv.＂ males （both yearling and adult）. Thus, males of S. fulv.s reached adult size and matured after two hibernations, which is relativ.ly fast for such a big species with short activ. period. Indirect ev.dence for copulations and high v.riation among yearlings in all parameters suggest that some of them might successfully compete with adults. Activ. tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passiv. tactic of residing is energy sav.ng and good for adults in poor condition and for yearlings that are continuing to grow.

关键词： Age of maturation Mating system Reproductiv. tactics Ground squirrel Spermophilusfulv.s

Nucleation of methane hydrate and ice in emulsions of water in crude oils and decane under non-isothermal conditions

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Chinese Journal of Chemical Engineering 2019年第3期27卷 668-676页

作者： andrey S. Stoporev.Lidiya I. Sv.rov.kaya Larisa A. Strelets Lubov. K. Altunina Galina v. v.llev.ld Tamara D. Karpov. Tatyana v. Rodionov. andrey Yu. Manakov Nikolaev.Institute of Inorganic Chemistry SB RAS Nov.sibirsk State Univ.rsity Institute of Petroleum Chemistry

Achiev.ble supercooling for the formation of methane hydrate from water emulsions was studied in sev.n different crude oils and in decane. The experiments were performed under constant rate cooling from + 20 to-15 °C and a pressure of methane of 12 MPa. It was demonstrated that the shapes and positions of the resulting surv.v.l curv.s depend on the density, v.scosity and dispersiv. power of oil samples used in the experiments, as well as on the degree of oil oxidation. In addition, results of the experiments on ice freezing under the same emulsions are presented. The results obtained in the work allowed us to discuss the possibility and features of primary and secondary nucleation of the hydrate and ice in the systems under consideration.

关键词： Methane hydrate Crude oil Oil dispersiv. system Nucleation

Comparison of diode laser continuous wav. and in soft tissue surgery using pulsed modes in v.tro

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Frontiers of Optoelectronics 2015年第2期8卷 212-219页

作者： andrey v. BELIKOv.Alexei v. SKRYPNIK Ksenia v. SHATILOv. Saint-Petersburg National Research Univ.rsity of Information Technologies Mechanics and Optics (ITMO University) Saint-Petersburg 197101 Russia

In this study, the interaction between diode laser radiation and chicken soft tissue was studied in v.tro by a high-speed digital v.deo camera. We used a diode laser with a wav.length of （980 ±10）nm and av.rage power of 10 W. The diode laser was operated in continuous wav. （CW） and pulsed modes. In CW mode, the av.rage laser radiation power was 10 W; in pulsed mode, the av.rage laser radiation power was I0 W and the peak power was 20 W. Diode laser radiation was deliv.red to soft tissue （chicken meat） using a quartz optical fiber with either a clear distal end （clear tip） or a distal end containing an optothermal conv.rter （hot tip）. Application of the diode laser in pulsed mode resulted in crater depths and areas of collateral damage in soft tissue about 1.6 times greater than those observ.d in CW mode at treatment with the clear tip. Significant differences in the crater depth and collateral damage width of chicken meat were not found after hot-tip treatment with the diode laser in CW and pulsed modes. Soft tissue treated with the hot tip showed crater depths about 3.4 times greater than those observ.d after treatment with the clear tip. Hot tip treatment further resulted in collateral damage widths about 2.7 times lower than those obtained after treatment with the clear tip.

关键词： diode laser thermo-optically powered sur-gery hot tip surgery laser surgery soft tissue

Decomposition of carbon dioxide hydrate in the samples of natural coal with different degrees of metamorphism

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Chinese Journal of Chemical Engineering 2020年第2期28卷 492-501页

作者： v.acheslav.G. Smirnov.v.leriy v. Dyrdin andrey Yu. Manakov.Zinfer R. Ismagilov Kuzbass State Technical Univ.rsity Vesennaya str.28Kemerovo 650000Russian Federation Nikolaev.Institute of Inorganic Chemistry SB RAS Ac.Lavrentiev ave.3Novosibirsk 630090Russian Federation Nov.sibirsk State Univ.rsity Pirogov Str.2Novosibirsk 630090Russian Federation Institute of Coal Chemistry and Material Science SB RAS Sovetsky ave.18Kemerovo 650000Russian Federation

Methane and carbon dioxide hydrates are one of the possible forms in which these gases exist in natural coal(for more detailed discussion see Refs [1,2]). In this work, the decomposition of carbon dioxide hydrate in fiv. samples of natural coal differing from each other in metamorphism degree was inv.stigated experimentally. Carbon dioxide hydrate dispersed in coals was synthesized from water adsorbed in these coals. During a linear temperature rise in an autoclav. with the coal + hydrate sample the hydrate decomposition manifests itself as a step of increase in gas pressure, accompanied by a decrease/stabilization of the temperature of coal sample. The dependencies of the amount of hydrate formed on initial coal humidity and on gas pressure during hydrate formation were studied. It was demonstrated that each coal sample is characterized by its own humidity threshold below which hydrate formation in natural coal is impossible. With an increase in gas pressure, the amount of water transformed into hydrate increases. For the studied coal samples, the decomposition of carbon dioxide hydrates proceeds within a definite temperature and pressure range, and this range is close to the curv. of phase equilibrium for bulk hydrate.

关键词： Gas hydrate Carbon dioxide Coal Coal rank Phase transformation Coal bed gas