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排序方式: 共有189条查询结果,搜索用时 15 毫秒
51.
S. Wan J. Gerl J. Cub J.M. Holeczek P. Reiter D. Schwalm T. Aumann K. Boretzky W. Dostal B. Eberlein H. Emling Ch. Ender Th.W. Elze H. Geissel A. Grünschloß R. Holzmann N. Iwasa M. Kaspar A. Kleinböhl O. Koschorrek Y. Leifels A. Leistenschneider I. Peter H. Schaffner C. Scheidenberger R. Schubart R. Schubert H. Simon G. Stengel A. Surowiec H.J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》1999,6(2):167-174
This work demonstrates the feasibility of in-beam %-spectroscopy employing radioactive ion beam species at relativistic energies of E = 210 ~ 280 A · MeV. Neutron-rich nuclei below 48Ca with neutron number between the two magic numbers 20 and 28 have been investigated. Using a Pb target, single step inelastic excitation originating mainly from Coulomb interaction takes place populating preferentially low-lying low-spin states and enabling the extraction of B(E2) values. On a C target, nucleon removal reactions are dominating and medium-spin states are populated thus offering spectroscopic information in neighboring nuclei. Cross sections of inelastic excitation are determined and compared to coupled-channels calculations. Two new states of the very neutron-rich nucleus 44Ar at 1.78(8) MeV and 2.61(16) MeV are deduced from %-transitions. 相似文献
52.
Approaches for classifying resolvable balanced incomplete block designs (RBIBDs) are surveyed. The main approaches can roughly
be divided into two types: those building up a design parallel class by parallel class and those proceeding point by point.
With an algorithm of the latter type — and by refining ideas dating back to 1917 and the doctoral thesis by Pieter Mulder
— it is shown that the list of seven known resolutions of 2-(28, 4, 1) designs is complete; these objects are also known as
the resolutions of unitals on 28 points.
This research was supported in part by the Academy of Finland, Grants No. 107493, 110196, and 117499. 相似文献
53.
First-principles calculations are carried out on models for the Z(1)/Z(2) defects in 4H-SiC which are found in as-grown and irradiated n-type material. We show that an interstitial-nitrogen-interstitial-carbon defect is exceptionally thermally stable, bistable, and has negative-U character with donor and acceptor levels close to those attributed to the defect. 相似文献
54.
Patrick Eberlein 《Linear and Multilinear Algebra》1980,9(3):231-236
To my Father, William F. Eberlein. 相似文献
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Meister M Markenroth K Aleksandrov D Aumann T Axelsson L Baumann T Borge MJ Chulkov LV Dostal W Eberlein B Elze TW Emling H Forssén C Geissel H Hellström M Holzmann R Jonson B Kratz JV Kulessa R Leifels Y Leistenschneider A Mukha I Münzenberg G Nickel F Nilsson T Nyman G Richter A Riisager K Scheidenberger C Schrieder G Simon H Tengblad O Zhukov MV 《Physical review letters》2002,88(10):102501
Low-lying resonance states in 7He(6He+n), formed after fragmentation reactions of a 227 MeV/nucleon 8He beam on a carbon target, have been studied. Coincidences between 6He nuclei and neutrons, corresponding to the one-neutron knockout channel in 8He, were selected. The relative energy spectrum in the 6He+n system shows a structure, which is interpreted as the 7He ( Ipi = 3/2(-)) ground state, unbound with 0.43(2) MeV relative to the 6He+n system and a width of Gamma = 0.15(8) MeV overlapping with an excited ( Ipi = 1/2(-)) state observed at 1.0(1) MeV with a width of Gamma = 0.75(8) MeV. 相似文献
59.
Patrik Gavelin Patric Jannasch Bengt Wessln 《Journal of polymer science. Part A, Polymer chemistry》2001,39(13):2223-2232
Amphiphilic graft copolymers were prepared via the radical copolymerization of poly(ethylene oxide) (PEO) macromonomers with fluorocarbon or hydrocarbon acrylates in toluene with 2,2′‐azobisisobutyronitrile (AIBN) as an initiator. 1H NMR spectroscopy confirmed that the composition of the graft copolymers corresponded well to the monomer feed. For gel electrolytes prepared from the amphiphilic copolymers, the nature of the ionophobic parts of the amphiphilic graft copolymers had a great influence on the ion conductivity. Gel electrolytes based on graft copolymers containing fluorocarbon side chains showed significantly higher ion conductivity than electrolytes based on graft copolymers containing hydrocarbon groups. The ambient‐temperature ion conductivity was about 2.6 mS/cm at 20 °C for a gel electrolyte based on an amphiphilic graft copolymer consisting of an acrylate backbone carrying PEO and fluorocarbon side chains. Corresponding gels based on graft copolymers with PEO side chains and hydrocarbon groups showed an ambient‐temperature ion conductivity of about 1.2 mS/cm. The gel electrolytes contained 30 wt % copolymer and 70 wt % 1 M LiPF6 in an ethylene carbonate/γ‐butyrolactone (2/1 w/w) mixture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2223–2232, 2001 相似文献
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