检索结果-南通市图书馆

Dust particle surface potential in an argonhelium plasma using the(r,q)-distribution function

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第9期76卷 141-148页

作者： Bahaaudin m Raffah A A Abid Abdullah Khan Amin Esmaeili Yas Al-Hadeethi m n S Qureshi Department of Physics Faculty of SciencesKing Abdulaziz UniversityJeddah 21589Saudi Arabia Lithography in Devices Fabrication and Development Research Group Deanship of Scientific ResearchKing Abdulaziz UniversityJeddah 21589Saudi Arabia Joint Laboratory of Plasma Application Technology Institute of Advanced TechnologyUniversity of Science and Technology of ChinaHefei230026China CAS Key Laboratory of Geospace Environment University of Science and Technology of ChinaHefei230026China Department of Physics Zhejiang Normal UniversityJinhua321005China Department of Physics Graduate School of ScienceTokyo Metropolitan UniversityMinami-Osawa 1-1Hachioji City192-0397Japan Department of Physics GC UniversityLahore 54000Pakistan

In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution *** studies have reported the argon-helium plasma and conducted a brief theoretical and experimental *** deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution *** this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality *** numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and *** is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density *** incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonmaxwellian dusty(complex)plasma is briefly examined.

关键词： dusty plasma dust charge potential plasma physics helium argon plasma r q distribution function non-maxwellian distribution

On thermoelastic problem based on four theories with the efficiency of the magnetic field and gravity

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2024年第4期9卷 338-347页

作者： A.A.Kilany A.n.Abd-alla A.m.Abd-Alla S.m.Abo-Dahab Department of mathematics Faculty of ScienceSohag UniversitySohag 82524 Egypt Department of Computer Science Faculty of Computers and InformationLuxor UniversityEgypt Department of mathematics Faculty of ScienceSouth Valley UniversityQena 83523Egypt

The fundamental objective of this paper is to study the effectiveness of magnetic field and gravity on an isotropic homogeneous thermoelastic structure based on four theories of generalized *** another meaning,the models of coupled dynamic theory(CDT),Lord-Shulman(LS),Green-Lindsay(GL)as well as Green-naghdi(Gn II)will be taken in the ***,applying the harmonic method(normal mode technique),the solution of the governing equations and the expressions for the components of the displacement,temperature and(mechanical and maxwell’s)stresses is taken into account and calculated *** impacts of the gravity and magnetic field are illustrated graphically which are pronounced on the different physical ***,the results of some research that others have previously obtained may be found some or all of them as special cases from this study.

关键词： Generalized thermoelasticity Gravity magnetic field Green and naghdi TheoryⅡ normal mode approach

Long-term monitoring reveals the effect of precipitation and silviculture on nothofagus regeneration in northern Patagonia mixed forests

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological Processes 2024年第2期13卷 103-117页

作者： Georgina Sola Camila mateo Alejandro Dezzotti Paula marchelli Hernán Attis Beltrán Renato Sbrancia Luis Chauchard marcelo González Pe?alba martín Lara Verónica El mujtar Consejo nacional de Investigaciones Científicas y Técnicas (COnICET ) Asentamiento Universitario San martín de los Andes (AUSmA-UnCo) Instituto de Investigaciones Forestales y Agropecuarias Bariloche (IFAB) Instituto Nacional de Tecnología Agropecuaria (INTA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Departamento de Conservación y manejo Parque Nacional Lanín- Administración de Parques Nacionales (PNL-APN)

Background Tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests. northwestern Patagonia from Argentina is occupied by nothofagus alpina（na）, n. obliqua（no）, and n. dombeyi（nd） forests that grow along an intense precipitation gradient, managed throughout shelterwood silvicultural system by technicians of the Lanin natural Reserve. The objective of this study was to evaluate the influence of seeding cuttings over the dynamics of nothofagus mixed forests across landscape（precipitation gradient） based mainly on the composition and abundance of tree regeneration, permanent sampling plots and generalized linear mixed models. In particular, we analysed:（i） the structure of sexual and asexual regeneration during nd > 20 years after harvest（the dynamics of managed forests）, and（ii） the structure of sexual regeneration in primary and managed forests after > 20 years of harvest（the effect of silviculture）.Results nd was the most abundant species in the regeneration of managed forests during all periods in both sites despite its lower contribution to the adult cohort. During the 10–20 years period after harvest, the humid site exhibited higher regeneration density than the mesic site(120,000 and 6000 ind ha-1, respectively), and it decreased afterwards. The number of established regeneration（> 2 m height） was lower for na in the mesic site and for no in the humid site(0 and 57 ind ha-1, respectively). However, in comparison to no, na showed a higher number of sprouted stumps and sprouts per stump, and a higher sprout height in the mesic site. no exhibited higher sprout mortality in the humid site. Finally, the regeneration of primary forests showed lower density and height, and a more balanced composition than that of managed *** The silvicultural effects on the mixed forest regeneration dynamics was strongly influenced by the condition of sites. Therefore, management prescriptions should be adj

关键词： nothofagus alpina nothofagus obliqua nothofagus dombeyi Basal sprouting Shelterwood silvicultural system Ecological resilience

Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Clean Energy 2024年第1期8卷 188-196页

作者： Basem E.Elnagi Ahmed m.Ismaiel Hany S.E.mansour m.n.Abd-Alwahab Electrical Engineering Department Faculty of EngineeringSuez Canal UniversityIsmailia 41522Egypt

A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost *** was directly coupled to a single-phase(two levels-four pulses)inverter without a *** pulse-width modu-lation signal was used to independently regulate every converter *** converter was modelled using a mATLAB®/Simulink®environment and an appropriate voltage control *** analysis features of the suggested circuit were created and,through established experiments,the simulation results were verified.A single-phase(two levels-four pulses)inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage *** matches the voltage of the network in terms of amplitude and frequency.A sinusoidal pulse-width modulation approach was performed using a single-phase(two levels-four pulses)pulse-width modulation *** results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63μs compared with 180μs in conventional techniques.

关键词： PEm fuel cell pulse-width modulation single-phase inverter and double-stage DC/DC boost converter

Rare earth based mgPm_(2)X_(4)(X=S,Se) spinel chalcogenides for spintronic and thermoelectric applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1577-1585,I0006页

作者： Tariq m.Al-Daraghmeh Omar Zayed Ghulam m.mustafa Taharh Zelai Bisma Younas Hind Albalawi S.Bouzgarrou othman Hakami Q.mahmood Khaild I.Hussein Basic Sciences Department King Abdullah Ⅱ School of EngineeringPrincess Sumaya University For TechnologyP.O.Box 1438Al-jubaiha11941AmmanJordan Department of Physics Division of Science&TechnologyUniversity of EducationLahorePakistan Department of Physics Faculty of ScienceJazan University JazanSaudi Arabia Department of Physics The University of LahoreLahorePakistan Department of Physics College of SciencesPrincess Nourah bint Abdulrahman University(PNU)P.O.Box 84428Riyadh11671Saudi Arabia Department of Physics College of ScienceQassim UniversityPo.64BuraidahSaudi Arabia Laboratoire de microelectronique et Instrumentation(UR 03/13-04) Faculte des Sciences de MonastirAvenue de I'Environnement 5000MonastirTunisia Department of Chemistry Faculty of ScienceJazan University JazanSaudi Arabia Basic&Applied Scientific Research Center Department of PhysicsCollege of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam 31441Saudi Arabia Department of Radiological Sciences College of Applied Medical SciencesKing Khalid UniversityAbha61421Saudi Arabia

In current report,the structural,magnetic,and thermoelectric properties of RE doped mgPm_(2)X_(4)(X=S,Se) spinels were *** energy difference in ferromagnetic and antiferromagnetic states reveals the stability of mgPm_(2)(S/Se)_(4) in the ferromagnetic *** co mputation of enthalpy of formation also ascertains thermodynamic stability of crystal ***-dependent band structure and density of states analysis reveal ferromagnetic semiconducting character showing different electronic behavior in both spin *** room temperature ferromagnetism,spin polarization and Curie temperature are estimated from exchange energies *** addition,exchange constants(n_(0)α and n_(0)β),exchange energy Δ_(x)(pd),crystal ifeld energy,and double exchange mechanism were studied to explore the magnetic ***,the electrical conductivity,thermal conductivity,Seebeck co-efficient,and power factor show effect on electrons spin and their potential for thermoelectric devices.

关键词： Rare earth elements Spintronic applications Thermoelectric effects Exchange energies

Soil organic carbon stocks in native forest of Argentina:a useful surrogate for mitigation and conservation planning under climate variability

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2024年第1期13卷 3-24页

作者： Pablo L.Peri Juan Gaitán matías mastrangelo marcelo nosetto Pablo E.Villagra Ezequiel Balducci martín Pinazo Roxana P.Eclesia Alejandra Von Wallis Sebastián Villarino Francisco Alaggia marina González Polo Silvina manrique Pablo A.meglioli Julián Rodríguez-Souilla martín mónaco Jimena E.Chaves Ariel medina Ignacio Gasparri Eugenio Alvarez Arnesi maría Paula Barral Axel von müller norberto m.Pahr Josefina Uribe Echevarria Pedro Fernández marina morsucci Dardo López Juan manuel Cellini Leandro Alvarez Ignacio Barberis Hernán Colomb Ludmila La manna Sebastián Barbaro Cecilia Blundo Ximena Sirimarco Laura Cavallero Gualberto Zalazar Guillermo martínez Pastur Instituto nacional de Tecnología Agropecuaria (InTA) Universidad nacional de la Patagonia Austral (UnPA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Universidad nacional de Luján Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Grupo de Estudio de Agroecosistemas y Paisajes Rurales (GEAP) Universidad Nacional de Mar del Plata Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET ) CCT San Luis Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Instituto Argentino de nivología Glaciología y Ciencias Ambientales (IANIGLA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Universidad Nacional de Cuyo Instituto de Investigaciones en Biodiversidad y medioambiente (InIBIOmA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Instituto de Investigaciones en Energía no Convencional CCT Salta-JujuyConsejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Laboratorio de Recursos Agroforestales Centro Austral de Investigaciones Científicas (CADIC) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Dirección nacional de Bosques Ministerio de Ambiente y Desarrollo Sostenible de la Nación Instituto de Ecología Regional Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET )Universidad Nacional de Tucumán Universidad nacional de Rosario Instituto de Investigaciones en Ciencias Agrarias de Rosario Centro Científico Tecnológico CONICET Grupo de Estudio de Agroecosistemas y Paisajes Rurales (GEAP) Universidad Nacional de Mar del Plata Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Laboratorio de Investigaciones en maderas (LImAD) Universidad Nacional de La Plata (UNLP) Administración de Parques nacionales (APn) Parque Nacional Los Alerces Centro de Estudios Ambientales Integrados (CEAI) Universidad Nacional de la Patagonia San Juan Bosco (UNPASJB) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET )

Background The nationally determined contribution（nDC） presented by Argentina within the framework of the Paris Agreement is aligned with the decisions made in the context of the United nations Framework Conven-tion on Climate Change（UnFCCC） on the reduction of emissions derived from deforestation and forest degradation, as well as forest carbon conservation（REDD+）. In addition, climate change constitutes one of the greatest threats to forest biodiversity and ecosystem services. However, the soil organic carbon（SOC） stocks of native forests have not been incorporated into the Forest Reference Emission Levels calculations and for conservation planning under cli-mate variability due to a lack of information. The objectives of this study were:（i） to model SOC stocks to 30 cm of native forests at a national scale using climatic, topographic and vegetation as predictor variables, and（ii） to relate SOC stocks with spatial–temporal remotely sensed indices to determine biodiversity conservation concerns due to threats from high inter-annual climate *** We used 1040 forest soil samples（0–30 cm） to generate spatially explicit estimates of SOC native forests in Argentina at a spatial resolution of approximately 200 m. We selected 52 potential predictive environmental covari-ates, which represent key factors for the spatial distribution of SOC. All covariate maps were uploaded to the Google Earth Engine cloud-based computing platform for subsequent modelling. To determine the biodiversity threats from high inter-annual climate variability, we employed the spatial–temporal satellite-derived indices based on Enhanced Vegetation Index（EVI） and land surface temperature（LST） images from Landsat *** SOC model（0–30 cm depth） prediction accounted for 69% of the variation of this soil property across the whole native forest coverage in Argentina. Total mean SOC stock reached 2.81 Pg C（2.71–2.84 Pg C with a probability of 90%） for a total area of 460,790 km2,

关键词： Soil organic carbon Biodiversity native forest Climate change mitigation modelling Resilience

The effectiveness of different wear indicators in quantifying wear on railway wheels of freight wagons

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Railway Engineering Science 2024年第3期32卷 307-323页

作者： Philipe Augusto de Paula Pacheco m.magelli matheus Valente Lopes Pedro Henrique Alves Correa n.Zampieri n.Bosso Auteliano Antunes dos Santos Federal Institute of the Southeast of minas Gerais(IF Sudeste mG) Técnico PanamáStreet 45Santos DumontMG 36246-311Brazil Railway Laboratory(Lafer) Universidade Estadual de Campinas(UNICAMP)Mendeleyev Street 200CampinasSP 13083-872Brazil Department of mechanical and Aerospace Engineering Politecnico Di TorinoC.so Duca degli Abruzzi 2410129 TurinItaly

Railway infrastructure relies on the dynamic interaction between wheels and rails;thus,assessing wheel wear is a critical aspect of maintenance and *** paper focuses on the wheel-rail wear indicator T-gamma(Tγ).Amidst its use,it becomes apparent that Tγ,while valuable,fails to provide a comprehensive reflection of the actual material removal and actual contact format,which means that using only Tγas a target for optimization of profiles is not *** this work,three different freight wagons are evaluated:a meter-gauge and a broad-gauge heavy haul vehicles from South American railways,and a standard-gauge freight vehicle operated in Europe,with different axle loads and dissimilar new wheel/rail *** vehicles are subjected to comprehensive multibody simulations on various *** simulations aimed to elucidate the intricate relationship between different wear indicators:Tγ,wear index,material removal,and maximum wear depth,under diverse curves,non-compensated lateral accelerations(A_(nc)),and *** findings showed a correlation of 0.96 between Tγand wear depth and 0.82 between wear index and material removed for the outer *** the results,the Tγis better than the wear index to be used when analyzing wear depth while the wear index is more suited to foresee the material *** results also show the low influence of A_(nc)on wear index and Tγ.By considering these factors together,the study aims to improve the understanding of wheel-rail wear by selecting the best wear analysis approaches based on the effectiveness of each parameter.

关键词： Wear index Wear volume Wear modeling Dynamic simulation

DFT investigation of half-metallic ferromagnetic rare earth based spinels mgHo_(2)Z_(4)(Z=S,Se)

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第1期42卷 121-128,I0005页

作者： maiza Zanib mumtaz manzoor n.A.noor m.Waqas Iqbal mazia Asghar H.H.Hegazy A.Laref Department of Physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced materials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics and Astronomy College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

Half-metallic ferromagnetism,mechanical as well as thermoelectric properties for rare earth-based spinels mgHo_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optimization was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approximation(GGA)to calculate the lattice constant of both spinels comparable to experimental *** addition,Born stability criteria and negative formation energy show that our studied spinels are also structurally and dynamically stable in the cubic *** ferromagnetic(Fm)state stability,we also calculated the energy differences among Fm,antiferromagnetic(AFm),and non-magnetic(nm)***,Curie temperatures of ferromagnetic phases were also *** used Trans-Blaha improved BeckeJohnson(TB-mBJ)potential functional for electronics as well as magnetic characteristics,which lead to the consistent explanation of half-metallic ferromagnetism,representing the whole band-occupancy in material with exact detail of density of states(DOS).The stable Fm state was examined in spinels due to the exchange splitting of Ho cation consisting of p-d hybridizations compatible with the result achieved for electronics band structure and ***,spin magnetic moment was explained in terms of anion,cation,and sharing charge on studied *** addition,the calculated thermoelectric properties clearly show that operation range of these systems may be utilized by future experimental works for identifying the potential applications of these systems.

关键词： Ho-based spinels DFT simulations mechanical parameters Electronic properties Hm ferromagnetism Figure of merit

Implications of regional identity for neural stem and progenitor cell transplantation in the injured or diseased nervous system

在线全文

学校读者我要写书评

暂无评论

neural Regeneration Research 2024年第4期19卷 715-716页

作者： Prakruthi Amar Kumar Jennifer n.Dulin Department of Biology Texas A&M UniversityCollege Station Texas A&m Institute for neuroscience Texas A&M UniversityCollege Station

neural stem and progenitor cell(nSPC)transpla ntation has emerged as a promising therapeutic strategy for replacing lost neuronal populations and repairing damaged neural circuits following nervous system injury and disease.A great deal of experimental work has investigated the biology of nSPC grafting in preclinical animal models;more recently.

关键词： neural system injured