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31.
H. De Witte A. N. Andreyev S. Dean S. Franchoo M. Huyse O. Ivanov U. Köster W. Kurcewicz J. Kurpeta A. Plochocki K. Van de Vel J. Van de Walle P. Van Duppen 《The European Physical Journal A - Hadrons and Nuclei》2005,23(2):243-247
A new measurement of the 200Fr -decay half-life, with improved accuracy compared to previous measurements, has been carried out at the Isolde-CERN on-line mass separator. A half-life of 49(4) ms has been obtained, which is substantially different from earlier literature values. For the 196At daughter decay, a half-life of 389(54) ms and an branching ratio b = 94(5)% were measured. In addition, the half-lives of 201, 203, 205Fr and 197,199At are reported. 相似文献
32.
Van Roosbroeck J Guénaut C Audi G Beck D Blaum K Bollen G Cederkall J Delahaye P De Maesschalck A De Witte H Fedorov D Fedoseyev VN Franchoo S Fynbo HO Górska M Herfurth F Heyde K Huyse M Kellerbauer A Kluge HJ Köster U Kruglov K Lunney D Mishin VI Mueller WF Nagy S Schwarz S Schweikhard L Smirnova NA Van de Vel K Van Duppen P Van Dyck A Walters WB Weissman L Yazidjian C 《Physical review letters》2004,92(11):112501
Using resonant laser ionization, beta-decay studies, and for the first time mass measurements, three beta-decaying states have been unambiguously identified in 70Cu. A mass excess of -62 976.1(1.6) keV and a half-life of 44.5(2) s for the (6-) ground state have been determined. The level energies of the (3-) isomer at 101.1(3) keV with T(1/2)=33(2) s and the 1+ isomer at 242.4(3) keV with T(1/2)=6.6(2) s are confirmed by high-precision mass measurements. The low-lying levels of 70Cu populated in the decay of 70Ni and in transfer reactions compare well with large-scale shell-model calculations, and the wave functions appear to be dominated by one proton-one neutron configurations outside the closed Z=28 shell and N=40 subshell. This does not apply to the 1+ state at 1980 keV which exhibits a particular feeding and deexcitation pattern not reproduced by the shell-model calculations. 相似文献
33.
The possibility of applying post-column reaction and chemiluminescence to determine organic peroxy compounds by RP-HPLC was investigated. Conditions of qualitative and quantitative analyses have been established. The applicability of the method has been demonstrated for a series of compounds representative of the most important groups of peroxy-type compounds, that is, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, and peroxyacids. 相似文献
34.
A. N. Andreyev D. Ackermann F. P. Heßberger S. Hofmann M. Huyse I. Kojouharov B. Kindler B. Lommel G. Münzenberg R. D. Page K. Van de Vel P. Van Duppen K. Heyde 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):55-64
Alpha-decay of the new nuclide 184Bi has been studied in the complete-fusion reaction 93Nb(94Mo, 3n)184Bi at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-
, recoil-
-
analysis and excitation functions measurements. Two
-decaying isomeric states in 184Bi with half-life values of 13(2) ms and 6.6(1.5) ms were identified. The
-branching ratio of 180Tl was deduced for the first time as
. Improved data on the fine-structure
-decay of 186Bi were obtained in the 93Nb(95Mo, 2n)186Bi reaction. A similarity of the decay energies and half-life values of 184,186Bi is pointed out and a possible explanation for this effect is suggested.Received: 14 March 2003, Revised: 29 April 2003, Published online: 2 September 2003PACS:
23.60.+e
decay - 27.70.+q
- 27.80.+w
K. Heyde: Present address: EP-ISOLDE, CERN, CH-1211, Geneva 23, Switzerland. 相似文献
35.
Abstract Instead of alkaline or alkaline-earth nitrides, fluoro-nitrides with mixed composition have been developed as flux-precursors for the elaboration process of c-BN. If the pressure and temperature conditions for the h-BN → c-BN conversion are sensibly reduced, the conversion rates are largely increased. On the other hand, such compounds are appropriate for growth of c-BN single crystal. 相似文献
36.
We consider mass-conserving self-similar solutions for Smoluchowski’s coagulation equation with kernel K(ξ,η)=(ξη) λ with λ∈(0,1/2). It is known that such self-similar solutions g(x) satisfy that x ?1+2λ g(x) is bounded above and below as x→0. In this paper we describe in detail via formal asymptotics the qualitative behavior of a suitably rescaled function h(x)=h λ x ?1+2λ g(x) in the limit λ→0. It turns out that \(h \sim 1+ C x^{\lambda/2} \cos(\sqrt{\lambda} \log x)\) as x→0. As x becomes larger h develops peaks of height 1/λ that are separated by large regions where h is small. Finally, h converges to zero exponentially fast as x→∞. Our analysis is based on different approximations of a nonlocal operator, that reduces the original equation in certain regimes to a system of ODE. 相似文献
37.
The plane-wave method is used to determine the spin-wave spectra in nanoscale one-dimensional magnonic crystals formed by
a periodic lattice of ferromagnetic stripes. The dynamic demagnetizing field in a new formulation is used in these calculations.
The calculated spectra of spin waves are compared with experimental data taken from literature and a good agreement is obtained.
The dependence of the spin-wave spectra on magnetic material parameters consisting of magnetic stripes is systematically studied.
We proved that the experimentally found magnonic band structure with two magnonic gaps is of magnetostatic nature. 相似文献
38.
Uniqueness of complete spacelike hypersurfaces via their higher order mean curvatures in a conformally stationary spacetime 下载免费PDF全文
Henrique Fernandes de Lima Marco Antonio Lázaro Velásquez 《Mathematische Nachrichten》2014,287(11-12):1223-1240
We study complete noncompact spacelike hypersurfaces immersed into conformally stationary spacetimes, that is, Lorentzian manifolds endowed with a timelike conformal vector field V. In this setting, by using as main analytical tool a suitable maximum principle for complete noncompact Riemannian manifolds, we establish new characterizations of totally umbilical hypersurfaces in terms of their higher order mean curvatures. For instance, supposing an appropriated restriction on the norm of the tangential component of the vector field V, we are able to show that such hypersurfaces must be totally umbilical provided that either some of their higher order mean curvatures are linearly related or one of them is constant. Applications to the so‐called generalized Robertson‐Walker spacetimes are given. In particular, we extend to the Lorentzian context a classical result due to Jellett 29 . 相似文献
39.
Henryk Krawczyk Marcin
liwiski Wojciech M. Wolf 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o897-o899
The title compound, C11H16O2, adopts a semifolded conformation with the δ‐lactone and cyclohexane rings almost perpendicular to one another. The β‐methyl substituent occupies an axial position with respect to the cyclohexane ring. The δ‐lactone moiety adopts a slightly distorted half‐chair arrangement, while the cyclohexane ring exists in an almost ideal chair conformation. 相似文献
40.
María José Camarasa Ana San-Félix María Jesús Pérez-Pérez Sonsoles Velázquez Rosa Alvarez Cristina Chamorro 《Journal of carbohydrate chemistry》2013,32(4-5):451-469
1. INTRODUCTION AIDS will still be one of the most important challenges for the Scientific Community in the approaching new century. Since the identification, in 1983-84,1,2 of human immunodeficiency virus (HIV) as the etiological agent of AIDS, significant progress has been made in the treatment of HIV-infected patients. This has been in part due to the discovery and clinical use of an increasing number of anti-HIV drugs. However, while highly active antiretroviral therapy (HAART)3 approaches have reduced the morbidity and mortality, the intertwined problems of drug induced viral resistance, poor compliance with complex regimens and therapy failure continue. Therefore, there remains a pressing need for the development of new antiviral agents that can be used not only as first line therapeutic candidates, but also in the antiretroviral-experienced patient population. 相似文献