检索结果-南通市图书馆

Li.i. CYCLES AND i.VARi.nt PARABOLA i. A KUKLES SYSTEM OF DEGREE THREE

在线全文

学校读者我要写书评

暂无评论

Acta Mathemati.a Sci.nti. 2008年第4期28卷 865-869页

作者：刘振海 E.Sáez i.szántó Department of Mathemati.s Changsha University of Sciences and Techndogy Departamento de Matemáti.a Universidad Tcnica Federico Santa MariaCasilla 110-VValparaisoChile

i. thi. arti.le,the authors consi.er a class of Kukles planar polynomi.l di.ferenti.l system of degree three havi.g an i.vari.nt *** thi. class of second-order di.ferenti.l systems,i. i. shown that for certai. values of the parameters the i.vari.nt parabola coexi.ts wi.h a *** other values i. can coexi.t wi.h one,two or three small ampli.ude li.i. cycles whi.h are constructed by Hopf *** result gi.es an answer for the questi.n gi.en i.[4],about the exi.tence of li.i. cycles for such class of system.

关键词： Kukles system li.i. cycles i.vari.nt algebrai. curves

Arcti. sea-i.e extent: No record mi.i.um i. 2023 or recent years

在线全文

学校读者我要写书评

暂无评论

Atmospheri. and Oceani. Sci.nce Letters 2025年第1期18卷 52-55页

作者： Ola M.Johannessen Tor i.Olaussen Nansen Sci.nti.i. Soci.ty BergenNorway Nansen Envi.onmental and Remote Sensi.g Center BergenNorway

Arcti. sea-i.e extent reaches i.s mi.i.um each year i. September. On 11 September 2023 the mi.i.um was 4.969 mi.li.n square ki.ometers(***^(2)). Thi. was not a record low, whi.h occurred i. 2012, when the mi.i.um was 4.175 ***^(2), 0.794 ***^(2) less than the mi.i.um i. 2023. However, the i.e extent had decreased by 0.432 ***^(2) compared wi.h 2022. Nevertheless, the summer melti.g i. 2023 was remarkably less than expected when consi.eri.g the strong heat waves i. the atmosphere and ocean, wi.h record temperatures set around the world. i. general, there i. a hi.h correlati.n between the long-term decrease i. sea-i.e extent and the i.creasi.g CO_(2) i. the atmosphere, where the i.crease of CO_(2) i. recent decades explai.s about 80% of the decrease i. sea i.e i. September, whi.e the remai.der i. caused by natural vari.bi.i.y.

关键词： Sea i.e Arcti. Mi.i.um i.e Cli.ate

Uni.i.d treatment of one-range addi.i.n theorems for i.teger and non-i.teger n-STO, -GTO and -generali.ed exponenti.l type orbi.als wi.h hyperboli. cosi.e i. posi.i.n, momentum and four-di.ensi.nal spaces

在线全文

学校读者我要写书评

暂无评论

Chi.ese Physi.s B 2012年第9期21卷 176-178页

作者： i. i. Gusei.ov Department of Physi.s Faculty of Arts and Sciences Onsekiz Mart University

Si.pler formulas are deri.ed for one-range addi.i.n theorems for the i.teger and noni.teger n generali.ed ex- ponenti.l type orbi.als, momentum space orbi.als, and hyperspheri.al harmoni.s wi.h hyperboli. cosi.e （GETO HC, GMSO HC, and GHSH HC） i. posi.i.n, momentum and four-di.ensi.nal spaces, respecti.ely. The fi.al results are expressed i. terms of one-range addi.i.n theorems of complete orthonormal sets of Ca-exponenti.l type orbi.als, Ca- momentum space orbi.als and za-hyperspheri.al harmoni.s. We noti.e that the one-range addi.i.n theorems for i.teger and noni.teger n-Slater type orbi.als and Gaussi.n type orbi.als i. posi.i.n, momentum and four di.ensi.nal spaces are speci.l cases of GETO HC, GMSO HC, and GHSH HC. The theorems presented can be useful i. the accurate study of the electroni. structure of atomi. and molecular systems.

关键词： electroni. structure generali.ed exponenti.l type orbi.als one-range addi.i.n theorems,Hartree-Fock-Roothaan equati.ns

One-Range Addi.i.n Theorems i. Terms of ψ^α -ETOs for STOs and Coulomb-Yukawa Li.e Correlated i.teracti.n Potenti.ls of i.teger and Noni.teger i.di.es

在线全文

学校读者我要写书评

暂无评论

Chi.ese Physi.s Letters 2008年第12期25卷 4240-4243页

作者： i. i. Gusei.ov Department of Physi.s Faculty of Arts and Sciences Onsekiz Mart University Canakkale Turkey

The expansi.n formulas i. terms of complete orthonormal sets of ψ^α -exponenti.l type orbi.als are establi.hed for the Slater type orbi.als and Coulomb-Yukawa-li.e correlated i.teracti.n potenti.ls of i.teger and noni.teger i.di.es. These relati.ns are used i. obtai.i.g thei. unsymmetri.al and symmetri.al one-range addi.i.n theorems. The fi.al results are especi.lly useful i. the calculati.ns of multi.entre multi.lectron i.tegrals occurri.g when Hartree-Fock-Roothaan and expli.i.ly correlated methods are employed.

关键词： orthonormal set expansi.n formula

Sci.ntometri.s: untangli.g the topi.s

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

Nati.nal Sci.nce Revi.w 2014年第3期1卷 343-345页

作者： ádám szántó-Várnagy Péter Pollner Tamás Vi.sek i.lés J. Farkas i.sti.ute of Physi.s Eotvos University

Measuri.g sci.nce i. based on compari.g arti.les to si.i.ar ***,keyword-based groups of themati.ally si.i.ar arti.les are domi.antly *** small si.es keep the stati.ti.al errors of compari.ons *** the growi.g avai.abi.i.y of bi.li.graphi. data,such stati.ti.al errors can be reduced by mergi.g methods of themati. groupi.g,ci.ati.n networks and keyword

关键词： untangli.g the topi.s Sci.ntometri.s APS ERC than

Test measurements for accuracy of absolute and relati.e GPS posi.i.ni.g

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2005年第S1期15卷 299-303页

作者： i. Havasi Uni.ersi.y of Mi.kolc Hungary

The paper, after the i.troducti.n, bri.fly outli.es the pri.ci.les of both absolute and relati.e GPS posi.i.ni.g. i. deals wi.h factors and error resources affecti.g the accuracy of these surveyi.g procedures. i. revi.ws the geodeti. determi.ati.n of a reference poi.t and a base li.e used for the test measurements. The study descri.es the completed test measurements, and on the basi. of results, i. draws the conclusi.ns for the accuracy of the i.vesti.ated surveyi.g methods. Fi.ally, consi.eri.g these accuracy measures, thei. possi.le appli.ati.n i. mi.e surveyi.g i. also menti.ned very shortly.

关键词： GPS surveyi.g methods factors and errors test measurements accuracy

Vi.cous Dark Energy Models wi.h Vari.ble G and A

在线全文

学校读者我要写书评

暂无评论

Chi.ese Physi.s Letters 2008年第10期25卷 3834-3836页

作者： Arbab i. Arbab Department of Physi.s Faculty of Science University of Khartoum PO Box 321 Khartoum 11115 SudanDepartment of Physics and Applied Mathematics Faculty of Applied Sciences and Computer Omdurman Ahlia University PO Box 7S6 Omdurman Sudan

We consi.er a cosmologi.al model wi.h bulk vi.cosi.y η and vari.ble cosmologi.al A ∝p^-α, alpha = const and gravi.ati.nal G constants. The model exhi.i.s many i.teresti.g cosmologi.al features. i.flati.n proceeds du to the presence of bulk vi.cosi.y and dark energy wi.hout requi.i.g the equati.n of state p =-p. Duri.g the i.flati.nary era the energy densi.y p does not remai. constant, as i. the de-Si.ter type. Moreover, the cosmologi.al and gravi.ati.nal constants i.crease exponenti.lly wi.h ti.e, whereas the energy densi.y and vi.cosi.y decrease exponenti.lly wi.h ti.e. The rate of mass creati.n duri.g i.flati.n i. found to be very huge suggesti.g that all matter i. the uni.erse i. created duri.g i.flati.n.

关键词： the power-law exponents preci.i.ati.n durati.e abrupt preci.i.ati.n change

Hardness of Mn_2V_2O_7 thi. fi.ms and i.s i.fluenti.l factors

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

i.ternati.nal Journal of Mi.erals,Metallurgy and Materi.ls 2015年第9期22卷 987-991页

作者： i. Aft i. Kari.er Department of Sci.nce Educati.n Faculty of Education Erciyes University Kayseri 38039 Turkey

Mn2V2O7 thi. fi.ms were deposi.ed onto amorphous glass substrates usi.g a chemi.al bath deposi.i.n method and di.ferent deposi.i.n ti.e. X-ray di.fracti.n （XRD） analysi. was used to defi.e the structure of the fi.ms. Thei. roughness, thi.kness, and surface properti.s were evaluated through atomi. force mi.roscopy （AFM）. The hardness of the fi.ms was measured usi.g a nanohardness tester The fi.m thi.kness, average grai. si.e, and roughness were posi.i.ely correlated wi.h each other. These three parameters were observed to i.crease wi.h the deposi.i.n ti.e. The fi.m thi.kness and average grai. si.e were i.versely correlated wi.h the hardness and rough- ness. i. addi.i.n, the number of crystalli.es per uni. area and the di.locati.n densi.y were observed to be posi.i.ely correlated wi.h the hardness and roughness. Thi. study was desi.ned to eluci.ate and formali.e the underlyi.g reasons for these relati.nshi.s.

关键词： manganese vanadate thi. fi.ms nanohardness i.fluenci.g factors

Phantom Energy wi.h Vari.ble G and A

在线全文

学校读者我要写书评

暂无评论

Chi.ese Physi.s Letters 2008年第12期25卷 4497-4500页

作者： Arbab i. Arbab Department of Physi.s Faculty of Science University of Khartoum P.O. Box 321 Khartoum 11115 Sudan 2.Department of Physi.s and Appli.d Mathemati.s Faculty of Applied Sciences and Computer Omdurman Ahlia University P.O. Box 786 Omdurman Sudan

We i.vesti.ate a cosmologi.al model of a phantom energy wi.h a vari.ble cosmologi.al constant （∧） dependi.g on the energy densi.y （ρ） as ∧∝ρ^α,α=const and a vari.ble gravi.ati.nal constant G. The model requi.es α 〈 0 and a negati.e gravi.ati.nal constant. The cosmologi.al constant evolves wi.h ti.e as ∧ ∝ t^-2. For ω 〉 - 1 and α 〈 -1 the cosmologi.al constant ∧ 〈 0, G 〉 0 and ρ decrease wi.h cosmi. expansi.n. For ordi.ary energy （or dark energy）, i.e.ω 〉 -1, we have -1 〈 α〈 0 and β 〉 0 so that G〉0 i.creases wi.h ti.e and p decreases wi.h ti.e. Cosmi. accelerati.n wi.h dust parti.les i. granted, provi.ed -2/3 〈α〈 0 and ∧〉0.

关键词： fi.ld emi.si.n molybdenum di.xi.e enhancement factor