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Structural,morphological,optical and antibacterial performances of rare earth(Sm)-doped ZnO nanorods

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Journal of Rare Earths 2024年第11期42卷 2119-2127页

作者： A.Ravi J.Samuel S.Sahaya Jude Dhas S.Usharani Turibius Simon D.Senthil kumar S.k.Jasmin Vijitha A.Sivakumar Raju Suresh kumar c.S.Biju Department of Physics University College of Engineering Department of Physics and Research centre Malankara Catholic College Manonmaniam Sundaranar University Saveetha School of Engineering Saveetha Institute of Medical and Technical SciencesSaveetha University Department of chemistry S.I.V.E.T College Department of Biotechnology Vivekanandha College of Arts and Science for Woman (Autonomous) Department of Physics Vel Tech Rangarajan Dr.Sagunthala R & D Institute of Science and Technology Department of Physics & Research centre Muslim Arts College key Laboratory of High-temperature and High-pressure Study of the Earth's Interior Institute of GeochemistryChinese Academy of Sciences Department of chemistry College of ScienceKing Saud University Department of Physics St. Alphonsa College of Arts and Science

The significant rise of ultra-violet（UV） radiation and pathogenic infectious bacteria poses a serious threat to global *** researchers' interests are attracted by novel materials with strong UVblocking ability,antibacterial activity and low toxicity to other *** this case,a simple wet chemical method with different annealing temperatures（400,500,and 600℃） was employed to create highly effective rare earth（Sm）-doped ZnO ***（101） plane of wurtzite ZnO shifts towards a lower angle with increasing annealing temperature,according to the X-ray diffraction（XRD） study findings,which additionally establishes the consequence of lattice *** of doublet peaks of Sm 3d(Sm 3d5/2and Sm 3d3/2) in the X-ray photoelectron spectroscopy（XPS） spectrum clearly validates the substitution of Sm3+ions in the 500℃-annealed *** 500℃-annealed nanorods exhibit combined performances of the wide band gap,improved UV absorbance,and vivid green luminescent emission（563 nm）.Additio nally,the nanorods have favorable UV-blocking execution of 96% for UVA at 360 nm,92% for UVB at 320 nm,and 57% for UVc at 225 nm,which is greater than the majority of ZnO-related materials that have been reported up to this *** doping is also appropriate for improving bacterial inhibition against the two studied strains（Escherichia coli and Staphylococcus aureus）,in addition to the intriguing features discussed ***,with maximum inhibition zone diameters of 20±0.72 and 18±0.57 mm,respectively,these nanorods exhibit high inhibitory action against *** and *** bacterial *** rare earth-doped material developed during the current experiment,which was annealed at 500℃,could potentially serve as an effective replacement for UV-blocking and antibacterial material,especially for biomedical applications.

关键词： Bacterial inhibition Metal oxide Rare earth doping UV-Shielding Wet chemical method

Early Phases of Star Formation: Testing chemical Tools

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Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： N.c.Martinez S.Paron cONIcET-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-forming processes strongly influence the ISM ***,many high-quality databases are available at millimeter *** them,it is possible to carry out studies that review and deepen previous *** these studies involve large samples of sources,it is preferred to use direct tools to study the molecular *** the aim of testing these tools such as the use of the HcN/HNc ratio as a thermometer,and the use of H^(13)cO^(+),Hc_(3)N,N_(2)H^(+) and c_(2)H as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDcs),highmass protostellar objects(HMPOs),hot molecular cores(HMcs) and ultracompact H II *** found that the use of the HcN/HNc ratio as a universal thermometer in the ISM should be taken with care because the HcN optical depth is a big issue that can affect the ***,this tool should be utilized only after a careful analysis of the HcN spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption *** point out that the analysis of the emission of H^(13)cO^(+),Hc_(3)N,N_(2)H^(+) and c_(2)H could be useful to trace and distinguish regions among IRDcs,HMPOs and *** molecular line widths of these four species increase from the IRDc to the HMc stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular *** results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation ISM:molecules ISM:clouds

circulation Pattern controls of Summer Temperature Anomalies in Southern Africa

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Advances in Atmospheric Sciences 2024年第2期41卷 341-354页

作者： chibuike chiedozie IBEBUcHI cameron c.LEE Department of Geography Kent State UniversityKentOhio 44242USA climRISE Lab Kent State UniversityKentOhio 44242USA

This study investigates the relationship between circulation patterns and austral summer temperature anomalies in southern Africa. The results show that the formation of continental lows tends to increase the thickness of the lower atmosphere. Further, the distinct variabilities of high and low pressure under the circulation types, influence air mass advection from the adjacent oceans, as well as atmospheric stability over land. Stronger anticyclonic circulation at the western branch of the Mascarene high-pressure system enhances the low-level cold air advection by southeast winds,decreases the thickness, and lowers the temperature over a majority of the land in southern Africa. conversely, a weaker Mascarene High, coupled with enhanced cyclonic activity in the southwest Indian Ocean increases low-level warm air advection and increases temperature anomalies over vast regions in southern Africa. The ridging of a closed South Atlantic anticyclone at the southern coast of southern Africa results in colder temperatures near the tip of southern Africa due to enhanced low-level cold air advection by southeast winds. However, when the ridge is weak and westerly winds dominate the southern coast of southern Africa, these areas experience temperature increases. The northward track of the Southern Hemisphere mid-latitude cyclone, which can be linked to the negative Southern Annular Mode, reduces the temperature in the southwestern part of southern Africa. Also, during the analysis period, El Ni?o was associated with temperature increases over the central parts of southern Africa;while the positive Indian Ocean dipole was linked to a temperature increase over the northeastern, northwestern, and southwestern parts of southern Africa.

关键词： temperature circulation types Subtropical Indian Ocean dipole Southern Annular Mode El Ni?o Indian Ocean dipole Mascarene High South Atlantic anticyclone

Imprints of a gravitational wave through the weak field deflection of photons

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chinese Physics c 2024年第8期48卷 240-245页

作者： Reggie c.Pantig Ali Övgün Physics Department Mapúa University658 Muralla St.IntramurosManila 1002Philippines Physics Department Eastern Mediterranean UniversityFamagusta99628 North Cyprusvia Mersin 10Turkiye

In this study,we investigate the novel phenomenon of gravitational lensing experienced by gravitational waves traveling past a Schwarzschild black hole perturbed by a specific,first-order,polar gravitational *** apply the Gauss-Bonnet theorem,finding a topological contribution to the deflection of light rays passing near the black *** demonstrate that the deflection angle can be determined by analyzing a region entirely outside the path of the light ray,leading to a calculation based solely on the parameters of the perturbing wave(Legendre polynomial order,l;frequency,σ).This approach offers a unique perspective on gravitational lensing and expands our understanding of black hole interactions with gravitational waves.

关键词： supermassive black holes gravitational waves chaos weak deflection angle Gauss-Bonnet theorem

Thermal properties and high-temperature ablation of high-entropy (Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) coating on graphite substrate

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Journal of Advanced ceramics 2024年第8期13卷 1268-1281页

作者： Ana c.Feltrin Daniel Hedman Farid Akhtar Division of Materials Science Lulea University of TechnologyLulea 97187Sweden center for Multidimensional carbon Materials(cMcM) Institute for Basic Science(IBS)Ulsan 44919Republic of Korea

An entropy-stabilized multicomponent ultrahigh-temperature ceramic(UHTc)coating,(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2),on a graphite substrate was in-situ sintered by spark plasma sintering(SPs)from constituent transition metal diboride ***(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) coating had a hardness of 31.2±2.1 GPa and resisted 36.9 GPa of stress before delamination,as observed at the *** temperature-dependent thermal properties of the multicomponent diboride(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) were obtained by molecular dynamics(MD)simulations driven by a machine learning force field(MLFF)trained on density functional theory(DFT)*** thermal conductivity,density,heat capacity,and coefficient of thermal expansion obtained by the MD simulations were used in time-dependent thermal stress finite element model(FEM)*** low thermal conductivity(k^(-1))of the multicomponent diboride coupled with its similar coefficient of thermal expansion to that of graphite indicated that stresses of less than 10 GPa were generated at the interface at high temperatures,and therefore,the coating was mechanically resistant to the thermal stress induced during *** experiments at 220℃ showed that the multicomponent diboride coating was resistant to thermal stresses with no visible cracking or *** ablation mechanisms were mechanical denudation and evaporation of B_(2)O_(5) and light V-Ti oxides,which caused a decrease in the mass and thickness of the coating and resulted in mass and linear ablation rates of-0.51 mg·s^(-1) and -1.38μm·s^(-1),respectively,after 60 *** findings demonstrated the thermal and mechanical stability of multicomponent entropy-stabilized diborides as coatings for carbon materials in engineering components under extreme environments.

关键词： entropy-stabilized diborides ultrahigh temperature ceramics molecular dynamics(MD)simulations density functional theory(DFT) ablation properties

Experimental and numerical analysis of multi-chamber oscillating water column devices

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Journal of Hydrodynamics 2024年第3期36卷 492-503页

作者： Jorge Gadelho kourosh Rezanejad c.Guedes Soares centre for Marine Technology and Ocean Engineering(cENTEc) Instituto Superior TécnicoUniversidade de LisboaAvenida Rovisco PaisLisboaPortugal

A review of multi-chamber oscillating water column(OWc)device designs is *** significant variations of these devices are discussed,onshore OWc(OOWc)and a floating OWc(FOWc).The efficiency results of several theoretical studies based on low-and high-fidelity numerical models are presented and compared with the model scale ***,low-fidelity numerical models are very fast to run,but their accuracy is limited compared with high-fidelity numerical *** model experiments usually give results much more accurate than numerical models,but they need adequate facilities and are very *** the case of the OOWc,all models show a similar trend of total efficiency,but while the analytical model shows a maximum value of around 90%efficiency,the cFD model shows 60%,and the experiments only go up to 40%.The main reason is connected with the mathematical simplifications and assumptions that do not represent all the hydrodynamic and aerodynamic processes between the water,air,and *** the case of the FOWc,interestingly,the experimental results show a maximum efficiency of almost 100%,while the analytical model only predicts a maximum of 80%.The efficiency seems highly dependent on the heave motion resonance of the entire device,where the analytical model fails to predict this natural frequency.

关键词： Wave energy converters oscillating water column(OWc) multi-chambers experimental modelling numerical modelling

Fault Location Method for Overhead Feeders with Distributed Generation Units Based on Direct Load Flow Approach

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Journal of Modern Power Systems and clean Energy 2024年第4期12卷 1135-1146页

作者： charalampos G.Arsoniadis Vassilis c.Nikolaidis Department of Electrical and computer Engineering Democritus University of ThraceXanthi 67100Greece

This paper proposes a novel fault location method for overhead feeders,which is based on the direct load flow *** method is developed in the phase domain to effec-tively deal with unbalanced network conditions,while it can al-so handle any type of distributed generation(DG)units without requiring equivalent *** utilizing the line series parame-ters and synchronized or unsynchronized voltage and current phasor measurements taken from the sources,the method reli-ably identifies the most probable faulty *** the aid of an index,the exact faulty section among the multiple candi-dates is *** simulation studies for the IEEE 123-bus test feeder demonstrate that the proposed method accu-rately estimates the fault position under numerous short-circuit conditions with varying pre-fault system loading conditions,fault resistances,and measurement *** proposed meth-od is promising for practical applications due to the limited number of required measurement devices as well as the short computation time.

关键词： Fault location distribution system direct load flow distributed generation

Physical properties and maximum allowable mass-radius relation of complexity-free compact stellar objects within modified f(R,T)gravity formalism

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chinese Physics c 2024年第7期48卷 273-288页

作者： M.k.Jasim S.k.Maurya Abdelghani Errehymy Ali khalid Jassim kottakkaran Sooppy Nisar Abdel-Haleem Abdel-Aty Department of Mathematical and Physical Sciences College of Arts and SciencesUniversity of NizwaNizwa 616Sultanate of Oman Astrophysics Research centre School of MathematicsStatistics and Computer ScienceUniversity of KwaZulu-NatalPrivate Bag X54001Durban 4000South Africa Electrical Engineering Department College of EngineeringMustansiriyah UniversityBaghdadIraq Department of Mathematics College of Science and Humanities in AlkharjPrince Sattam bin Abdulaziz UniversityAl KharjSaudi Arabia Department of Physics College of SciencesUniversity of BishaP.O.Box 344Bisha 61922Saudi Arabia

This paper investigates the physical properties and predicted radii of compact stars generated by the Tolman-IV complexity-free model within the background of modified gravity theory,particularly the f(R,T)-gravity theory,under complexity formalism for a spherically symmetric spacetime proposed by ***[Phys Rev D 97:044010,2018].By solving the resulting set of differential equations,we obtain the explicit forms of the energy-momentum(EM)tensor components,including the density,radial pressure,and tangential *** influence of the parameterχon various physical properties of the star is thoroughly *** model undergoes a series of rigorous tests to determine its physical *** findings indicate that the model exhibits regularity,stability,and a surface with vanishing *** boundary of this surface is determined by carefully selecting the parameter *** complexity method employed in f(R,T)gravity offers an interesting approach for developing astrophysical models that are consistent with observable events as demonstrated by recent *** this regard,we use observational data from the GW190814 event,detected by the LIGO and Virgo observatories,to investigate the validity of the Tolman-IV model in f(R,T)*** analysis includes comparing the model's predictions with the observed characteristics of the compact object involved in the *** addition,data from two-millisecond pulsars,PSR J1614-2230 and PSR J0952-0607,are incorporated to further constrain the theoretical ***,we present a diagram depicting the relationship between the total mass and radius of the compact object candidates for different values ofχ.

关键词： complexity modified gravity compact Stars

Enhanced saturation magnetization in La^(3+) doped Nico ferrites prepared by sol-gel auto-combustion method

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Journal of Rare Earths 2024年第8期42卷 1546-1554,I0005页

作者： Maddileti Jelli Vidyasagar Thopudurthy krishna Reddy c.V. Department of Physics Rayalaseema UniversityKurnoolA.P518007.Iindia Department of Physics Government PolytechnicRayachotiA.P516269India

Lanthanum doped nickel-cobalt nano ferrites with chemical formula Ni_(0.5)co_(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared using a simple sol-gel auto combustion *** basic structural properties were determined by X-ray diffraction method and the formation of single phased spinel ferrite was *** crystalline size decreased from 25 to 11 nm and lattice parameter a increases with increase of La *** surface morphology of these ferrites was observed by field-emission scanning electron microscopy(FESEM) and agglomerated irregular grains are observed with increase of the rare earth element La ***-dispersive X-ray spectroscopy(EDX) result confirms the presence of the required *** Fourier transform infrared spectroscopy(FTIR) spectrum indicates the formation of the spinel ferrite structure with M-O *** direct band measurements from ultraviolet-visible spectroscopy(UV-Vis) spectroscopy indicate that the direct band gap decreases from 1.39 to 1.19 eV for x=0.05 to x=0.15,then increases to 1.28 eV for x=*** room temperature magnetic properties of these ferrites were studied by a vibrating sample magnetometer(VSM).The enhanced saturation magnetization of 49.73 emu/g is observed for x=0.10 and then saturation magnetizations are gradually decreased for x=0.15 and x=*** the remanent magnetization and coercivity also follow the same trend.

关键词： Ferrites Sol-gel auto combustion La doping Magnetic properties Rare earths