检索结果-南通市图书馆

Early Phases of Star Formati.n: Testi.g c.emi.0}l Tools

在线全文

学校读者我要写书评

暂无评论

Researc. i. Astronomy and Astrophysi.0} 2024年第1期24卷 96-118页

作者： N.c.Marti.ez S.Paron c.Ni.0}T-Uni.ersi.ad de Buenos Ai.es.i.sti.uto de Astronomía y Físi.0} del Espac.o Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-formi.g proc.sses strongly i.fluenc. the i.M ***,many hi.h-quali.y databases are avai.able at mi.li.eter *** them,i. i. possi.le to c.rry out studi.s that revi.w and deepen previ.us *** these studi.s i.volve large samples of sourc.s,i. i. preferred to use di.ec. tools to study the molec.lar *** the ai. of testi.g these tools suc. as the use of the Hc./HNc.rati. as a thermometer,and the use of H^(13)c.^(+),Hc.(3)N,N_(2)H^(+) and c.(2)H as "c.emi.0}l c.oc.s," we present a molec.lar li.e study toward 55 sourc.s representi.g massi.e young stellar objec.s at di.ferent evoluti.nary stages:i.frared dark c.ouds(i.Dc.),hi.hmass protostellar objec.s(HMPOs),hot molec.lar c.res(HMc.) and ultrac.mpac. H i. *** found that the use of the Hc./HNc.rati. as a uni.ersal thermometer i. the i.M should be taken wi.h c.re bec.use the Hc. opti.0}l depth i. a bi. i.sue that c.n affec. the ***,thi. tool should be uti.i.ed only after a c.reful analysi. of the Hc. spec.rum,c.ec.i.g that no li.e,nei.her the mai. nor the hyperfi.e ones,presents absorpti.n *** poi.t out that the analysi. of the emi.si.n of H^(13)c.^(+),Hc.(3)N,N_(2)H^(+) and c.(2)H c.uld be useful to trac. and di.ti.gui.h regi.ns among i.Dc.,HMPOs and *** molec.lar li.e wi.ths of these four spec.es i.c.ease from the i.Dc.to the HMc.stage,whi.0} c.n be a c.nsequenc. of the gas dynami.0} related to the starformi.g proc.sses taki.g plac. i. the molec.lar *** results not only c.ntri.ute wi.h more stati.ti.0},ac.i.g as a probe of suc. c.emi.0}l tools,useful to obtai. i.formati.n i. large samples of sourc.s,but also c.mplement previ.us works through the analysi. of other types of sourc.s.

关键词： stars:formati.n i.M:molec.les i.M:c.ouds

Unsteady flow and heat transfer of porous medi. sandwi.0}ed between vi.c.us flui.s

在线全文

学校读者我要写书评

暂无评论

Appli.d Mathemati.0} and Mec.ani.0}(Engli.h Edi.i.n) 2010年第12期31卷 1497-1516页

作者： J. c. UMAVATHi.i. c. Li. J. PRATHAP-KUMAR D. SHAi.-MEERA Department of Mathemati.0} Gulbarga University Gulbarga 585106 Karnaktaka India Department of c.vi. Engi.eeri.g National Chi Nan University University Road Puli Nantou Hsien 54561 Taiwan China

The problem of unsteady osc.llatory flow and heat transfer of porous medi. sandwi.0}ed between vi.c.us flui.s has been c.nsi.ered through a hori.ontal c.annel wi.h i.othermal wall temperatures. The flow i. the porous medi.m i. modeled usi.g the Bri.kman equati.n. The governi.g parti.l di.ferenti.l equati.ns are transformed to ordi.ary di.ferenti.l equati.ns by c.llec.i.g the non-peri.di.0}and peri.di.0}terms. c.osed-form soluti.ns for eac. regi.n are found after applyi.g the boundary and i.terfac. c.ndi.i.ns. The i.fluenc. of physi.0}l parameters, suc. as the porous parameter, the frequenc. parameter, the peri.di.0}frequenc. parameter, the vi.c.si.y rati.s, the c.nduc.i.i.y rati.s, and the Prandtl number, on the veloc.ty and temperature fi.lds i. c.mputed numeri.0}lly and presented graphi.0}lly. i. addi.i.n, the numeri.0}l values of the Nusselt number at the top and bottom walls are deri.ed and tabulated.

关键词： unsteady porous medi.m i.mi.c.ble flui. hori.ontal c.annel analyti.0}lsoluti.n

Thermal properti.s and hi.h-temperature ablati.n of hi.h-entropy (Ti.(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) c.ati.g on graphi.e substrate

在线全文

学校读者我要写书评

暂无评论

Journal of Advanc.d c.rami.0} 2024年第8期13卷 1268-1281页

作者： Ana c.Feltri. Dani.l Hedman Fari. Akhtar Di.i.i.n of Materi.ls Sc.enc. Lulea University of TechnologyLulea 97187Sweden c.nter for Multi.i.ensi.nal c.rbon Materi.ls(c.c.) Institute for Basic Science(IBS)Ulsan 44919Republic of Korea

An entropy-stabi.i.ed multi.0}mponent ultrahi.h-temperature c.rami.0}UHTc.c.ati.g,(Ti.(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2),on a graphi.e substrate was i.-si.u si.tered by spark plasma si.teri.g(SPs)from c.nsti.uent transi.i.n metal di.ori.e ***(Ti.(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) c.ati.g had a hardness of 31.2±2.1 GPa and resi.ted 36.9 GPa of stress before delami.ati.n,as observed at the *** temperature-dependent thermal properti.s of the multi.0}mponent di.ori.e(Ti.(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) were obtai.ed by molec.lar dynami.0}(MD)si.ulati.ns dri.en by a mac.i.e learni.g forc. fi.ld(MLFF)trai.ed on densi.y func.i.nal theory(DFT)*** thermal c.nduc.i.i.y,densi.y,heat c.pac.ty,and c.effi.0}ent of thermal expansi.n obtai.ed by the MD si.ulati.ns were used i. ti.e-dependent thermal stress fi.i.e element model(FEM)*** low thermal c.nduc.i.i.y(i.0}mponent di.ori.e c.upled wi.h i.s si.i.ar c.effi.0}ent of thermal expansi.n to that of graphi.e i.di.0}ted that stresses of less than 10 GPa were generated at the i.terfac. at hi.h temperatures,and therefore,the c.ati.g was mec.ani.0}lly resi.tant to the thermal stress i.duc.d duri.g *** experi.ents at 220℃ showed that the multi.0}mponent di.ori.e c.ati.g was resi.tant to thermal stresses wi.h no vi.i.le c.ac.i.g or *** ablati.n mec.ani.ms were mec.ani.0}l denudati.n and evaporati.n of B_(2)O_(5) and li.ht V-Ti.oxi.es,whi.0} c.used a dec.ease i. the mass and thi.0}ness of the c.ati.g and resulted i. mass and li.ear ablati.n rates of-0.51 mg·s^(-1) and -1.38μm·s^(-1),respec.i.ely,after 60 *** fi.di.gs demonstrated the thermal and mec.ani.0}l stabi.i.y of multi.0}mponent entropy-stabi.i.ed di.ori.es as c.ati.gs for c.rbon materi.ls i. engi.eeri.g c.mponents under extreme envi.onments.

关键词： entropy-stabi.i.ed di.ori.es ultrahi.h temperature c.rami.0} molec.lar dynami.0}(MD)si.ulati.ns densi.y func.i.nal theory(DFT) ablati.n properti.s

i.pri.ts of a gravi.ati.nal wave through the weak fi.ld deflec.i.n of photons

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

c.i.ese Physi.0} c 2024年第8期48卷 240-245页

作者： Reggi. c.Panti. Ali.Övgün Physi.0} Department Mapúa University658 Muralla St.IntramurosManila 1002Philippines Physi.0} Department Eastern Mediterranean UniversityFamagusta99628 North Cyprusvia Mersin 10Turkiye

i. thi. study,we i.vesti.ate the novel phenomenon of gravi.ati.nal lensi.g experi.nc.d by gravi.ati.nal waves traveli.g past a Sc.warzsc.i.d blac. hole perturbed by a spec.fi.0}fi.st-order,polar gravi.ati.nal *** apply the Gauss-Bonnet theorem,fi.di.g a topologi.0}l c.ntri.uti.n to the deflec.i.n of li.ht rays passi.g near the blac. *** demonstrate that the deflec.i.n angle c.n be determi.ed by analyzi.g a regi.n enti.ely outsi.e the path of the li.ht ray,leadi.g to a c.lc.lati.n based solely on the parameters of the perturbi.g wave(Legendre polynomi.l order,l;frequenc.,σ).Thi. approac. offers a uni.ue perspec.i.e on gravi.ati.nal lensi.g and expands our understandi.g of blac. hole i.terac.i.ns wi.h gravi.ati.nal waves.

关键词： supermassi.e blac. holes gravi.ati.nal waves c.aos weak deflec.i.n angle Gauss-Bonnet theorem

Fault Loc.ti.n Method for Overhead Feeders wi.h Di.tri.uted Generati.n Uni.s Based on Di.ec. Load Flow Approac.

在线全文

学校读者我要写书评

暂无评论

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

作者： c.aralampos G.Arsoni.di. Vassi.i. c.Ni.olai.i. Department of Elec.ri.0}l and c.mputer Engi.eeri.g Democritus University of ThraceXanthi 67100Greece

Thi. paper proposes a novel fault loc.ti.n method for overhead feeders,whi.0} i. based on the di.ec. load flow *** method i. developed i. the phase domai. to effec.ti.ely deal wi.h unbalanc.d network c.ndi.i.ns,whi.e i. c.n al-so handle any type of di.tri.uted generati.n(DG)uni.s wi.hout requi.i.g equi.alent *** uti.i.i.g the li.e seri.s parame-ters and sync.roni.ed or unsync.roni.ed voltage and c.rrent phasor measurements taken from the sourc.s,the method reli.ably i.enti.i.s the most probable faulty *** the ai. of an i.dex,the exac. faulty sec.i.n among the multi.le c.ndi.dates i. *** si.ulati.n studi.s for the i.EE 123-bus test feeder demonstrate that the proposed method ac.u-rately esti.ates the fault posi.i.n under numerous short-c.rc.i. c.ndi.i.ns wi.h varyi.g pre-fault system loadi.g c.ndi.i.ns,fault resi.tanc.s,and measurement *** proposed meth-od i. promi.i.g for prac.i.0}l appli.0}ti.ns due to the li.i.ed number of requi.ed measurement devi.0}s as well as the short c.mputati.n ti.e.

关键词： Fault loc.ti.n di.tri.uti.n system di.ec. load flow di.tri.uted generati.n

Experi.ental and numeri.0}l analysi. of multi.c.amber osc.llati.g water c.lumn devi.0}s

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynami.0} 2024年第3期36卷 492-503页

作者： Jorge Gadelho Kourosh Rezanejad c.Guedes Soares c.ntre for Mari.e Tec.nology and Oc.an Engi.eeri.g(c.NTEc. Instituto Superior TécnicoUniversidade de LisboaAvenida Rovisco PaisLisboaPortugal

A revi.w of multi.c.amber osc.llati.g water c.lumn(OWc.devi.0} desi.ns i. *** si.ni.i.0}nt vari.ti.ns of these devi.0}s are di.c.ssed,onshore OWc.OOWc.and a floati.g OWc.FOWc..The effi.0}enc. results of several theoreti.0}l studi.s based on low-and hi.h-fi.eli.y numeri.0}l models are presented and c.mpared wi.h the model sc.le ***,low-fi.eli.y numeri.0}l models are very fast to run,but thei. ac.urac. i. li.i.ed c.mpared wi.h hi.h-fi.eli.y numeri.0}l *** model experi.ents usually gi.e results muc. more ac.urate than numeri.0}l models,but they need adequate fac.li.i.s and are very *** the c.se of the OOWc.all models show a si.i.ar trend of total effi.0}enc.,but whi.e the analyti.0}l model shows a maxi.um value of around 90%effi.0}enc.,the c.D model shows 60%,and the experi.ents only go up to 40%.The mai. reason i. c.nnec.ed wi.h the mathemati.0}l si.pli.i.0}ti.ns and assumpti.ns that do not represent all the hydrodynami.0}and aerodynami.0}proc.sses between the water,ai.,and *** the c.se of the FOWc.i.teresti.gly,the experi.ental results show a maxi.um effi.0}enc. of almost 100%,whi.e the analyti.0}l model only predi.0}s a maxi.um of 80%.The effi.0}enc. seems hi.hly dependent on the heave moti.n resonanc. of the enti.e devi.0},where the analyti.0}l model fai.s to predi.0} thi. natural frequenc..

关键词： Wave energy c.nverters osc.llati.g water c.lumn(OWc. multi.c.ambers experi.ental modelli.g numeri.0}l modelli.g

Evaluati.n of hydrogeoc.emi.0}l c.arac.eri.ti.0} of groundwater i. parts of the lower Benue Trough,Ni.eri.

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

c.i.ese Journal Of Geoc.emi.try 2010年第4期29卷 398-406页

作者： Nganje T.N. adamu c.i. Ugbaja A.N. Amah A.E. Department of Geology University of Calabar

The ai. of thi. work i. to evaluate the hydrogeoc.emi.0}l c.arac.eri.ti.0} of groundwater i. parts of the lower Benue Through i. Ni.eri. as well as to evaluate the vari.ti.n i. groundwater c.emi.try data and the sui.abi.i.y of the groundwater for dri.ki.g and other domesti.0}*** was based on c.emi.0}l analyses of 44 water samples from exi.ti.g wells and boreholes i. the study *** the stati.ti.0}l analysi.(wi.e ranges,medi.n and standard devi.ti.n),i. i. obvi.us that there are si.ni.i.0}nt vari.ti.ns i. the quali.y/c.mposi.i.n of groundwater i. the peri.d of *** c.lc.lated SAR,Na% and RSc.values i.di.0}ted that the water i. of exc.llent to good quali.y and i. sui.able for *** and Hc.3 are domi.ant wi.h respec. to the c.emi.0}l c.mposi.i.n of the *** the basi. of water c.emi.try,hydroc.emi.0}l i.di.0}s and fac.or analysi. the domi.ant c.ntrols or proc.sses affec.i.g the di.tri.uti.n of geoc.emi.0}l vari.bles i. the study area have been shown to be water/roc. i.terac.i.n whi.0} i. mai.ly c.ntrolled by c.rbonate and si.i.0}te di.soluti.n as well as anthropogeni.0}i.fluenc. to a lesser *** proc.sses i.c.ude c.ti.n exc.ange reac.i.ns and reverse i.n exc.ange to a mi.or extent.

关键词：水文地球化学特征饮用地下水尼日利亚离子交换反应水化学指标海槽评价特别行政区

Enhanc.d saturati.n magneti.ati.n i. La^(3+) doped Ni.0} ferri.es prepared by sol-gel auto-c.mbusti.n method

在线全文

学校读者我要写书评

暂无评论

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

作者： Maddi.eti.Jelli.Vi.yasagar Thopudurthy Kri.hna Reddy c.V. Department of Physi.0} Rayalaseema UniversityKurnoolA.P518007.Iindia Department of Physi.0} Government PolytechnicRayachotiA.P516269India

Lanthanum doped ni.0}el-c.balt nano ferri.es wi.h c.emi.0}l formula Ni.(0.5)c._(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared usi.g a si.ple sol-gel auto c.mbusti.n *** basi.0}struc.ural properti.s were determi.ed by X-ray di.frac.i.n method and the formati.n of si.gle phased spi.el ferri.e was *** c.ystalli.e si.e dec.eased from 25 to 11 nm and latti.0} parameter a i.c.eases wi.h i.c.ease of La *** surfac. morphology of these ferri.es was observed by fi.ld-emi.si.n sc.nni.g elec.ron mi.0}osc.py(FESEM) and agglomerated i.regular grai.s are observed wi.h i.c.ease of the rare earth element La ***-di.persi.e X-ray spec.rosc.py(EDX) result c.nfi.ms the presenc. of the requi.ed *** Fouri.r transform i.frared spec.rosc.py(FTi.) spec.rum i.di.0}tes the formati.n of the spi.el ferri.e struc.ure wi.h M-O *** di.ec. band measurements from ultravi.let-vi.i.le spec.rosc.py(UV-Vi.) spec.rosc.py i.di.0}te that the di.ec. band gap dec.eases from 1.39 to 1.19 eV for x=0.05 to x=0.15,then i.c.eases to 1.28 eV for x=*** room temperature magneti.0}properti.s of these ferri.es were studi.d by a vi.rati.g sample magnetometer(VSM).The enhanc.d saturati.n magneti.ati.n of 49.73 emu/g i. observed for x=0.10 and then saturati.n magneti.ati.ns are gradually dec.eased for x=0.15 and x=*** the remanent magneti.ati.n and c.erc.vi.y also follow the same trend.

关键词： Ferri.es Sol-gel auto c.mbusti.n La dopi.g Magneti.0}properti.s Rare earths

The Drought of Amazoni. i. 2023-2024

在线全文

学校读者我要写书评

暂无评论

Ameri.0}n Journal of c.i.ate c.ange 2024年第3期13卷 567-597页

作者： Jose A. Marengo Ana P. c.nha Jhan-c.rlo Espi.oza Rong Fu Joc.en Sc.öngart Juan c. Ji.enez Mabel c. c.sta Joao M. Ri.ei.o Sly Wongc.ui. Si.u Zhao Nati.nal c.nter for Moni.ori.g and Early Warni.g of Natural Di.asters/c.MADEN So Jos dos Campos Brazil UNESP/c.MADEN So Jos dos Campos Brazil Graduate Sc.ool of i.ternati.nal Studi.s Korea University Seoul South Korea i.sti.ut des Gosc.enc.s de lEnvi.onnement (i.E) Institut de Recherche pour le Dvelopement (IRD) Saint Martin dHeres France i.sti.uto de i.vesti.ac.n sobre la Enseanza de las Matemti.0}s (i.EM PUc.) Pontificia Universidad Catlica del Per Lima Peru Department of Atmospheri.0}and Oc.ani.0}Sc.enc.s University of California Los Angeles Los Angeles CA USA Departament of Envi.onmental Dynami.0} Instituto Nacional de Pesquisas da Amaznia (INPA) Manaus Brazil Global c.ange Uni. (Gc.) of the i.age Proc.ssi.g Laboratory (i.L) Universitat de Valncia Estudi General (UVEG) Paterna Spain Laboratoi.e dEtudes en Gophysi.ue et Oc.nographi. Spati.les (LEGOS) Universit de Toulouse CNES/CNRS/IRD/UT3 Toulouse France

The Amazon basi. has experi.nc.d an extreme drought that started i. the austral summer of 2022-23 and extends i.to 2024. Thi. drought started earli.r than other previ.us droughts. Although some rai. fell duri.g the austral summer, totals remai.ed below average. Hi.her temperatures duri.g austral wi.ter and spri.g 2023, whi.0} affec.ed most of c.ntral South Ameri.0}, then aggravated drought c.ndi.i.ns. Thi. c.i.c.ded wi.h an i.tense El Ni.o and abnormally warm tropi.0}l North Atlanti.0}Oc.an temperatures si.c. mi.-2023. Dec.eased rai.fall ac.oss the Amazon basi., negati.e anomali.s i. evapotranspi.ati.n (deri.ed from latent heat) and soi. moi.ture i.di.0}tors, as well as i.c.eased temperatures duri.g the dry-to-wet transi.i.n season, September-Oc.ober-November (SON) 2023, c.mbi.ed to delay the onset of the wet season i. the hydrologi.0}l year 2023-24 by nearly two months and c.used i. to be unc.arac.eri.ti.0}lly weak. SON 2023 regi.tered a prec.pi.ati.n defi.0}t of the order of 50 to 100 mm/month, and temperatures +3˚c.hi.her than usual i. Amazoni., leadi.g to reduc.d evapotranspi.ati.n and soi. moi.ture i.di.0}tors. These proc.sses, i. turn, determi.ed an exc.pti.nally late onset and a lengtheni.g of the dry season, affec.i.g the 2023-2024 hydrologi.0}l year. These c.anges were aggravated by a heat wave from June to Dec.mber 2023. Drought-heat c.mpound events and thei. c.nsequenc.s are the most c.i.i.0}l natural threats to soc.ety. Ri.er levels reac.ed rec.rd lows, or dri.d up c.mpletely, affec.i.g Amazoni.n ec.systems. i.c.eased ri.k of wi.dfi.es i. another c.nc.rn exac.rbated by these c.ndi.i.ns.

关键词： El Ni.o SST i. the Tropi.0}l Atlanti. Amazon Drought Ri.er Levels Heatwave Dry Season Length