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101.
T. Rzaca-Urban W. Urban M. Saha Sarkar S. Sarkar J. L. Durell A. G. Smith B. J. Varley I. Ahmad 《The European Physical Journal A - Hadrons and Nuclei》2007,32(1):5-9
The Penning trap mass spectrometer JYFLTRAP, coupled to the Ion Guide Isotope Separator On-Line (IGISOL) facility at Jyv?skyl?,
was employed to measure the atomic masses of neutron-rich 70-73Ni and 73, 75Cu isotopes with a typical accuracy less than 5keV. The mass of 73Ni was measured for the first time. Comparisons with the previous data are discussed. Two-neutron separation energies show
a weak subshell closure at 68
28Ni40 . A well established proton shell gap is observed at Z = 28 . 相似文献
102.
A. Korgul H. Mach B. Fogelberg W. Urban W. Kurcewicz T. Rzaca-Urban P. Hoff H. Gausemel J. Galy J.L. Durell W.R. Phillips A.G. Smith B.J. Varley N. Schulz I. Ahmad L.R. Morss M. Górska V.I. Isakov K.I. Erokhina J. Blomqvist F. Andreozzi F. Coraggio A. Covello A. Gargano 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):181-184
Excited states in the 134Sb nucleus, populated in the β--decay of 134Sn, have been studied at the mass separator OSIRIS. The 134Sn activity was produced via fast neutron-induced fission of 238U target. A main result was the discovery of a very low-lying first-excited state of 134Sb, at 13keV, which has led to a strong revision of the level scheme. The new results are compared with different theoretical
calculations and with the known data for the analogous neutron and proton two-particle nucleus in the 208Pb region. On the basis of this comparison, the energy of the ( πg
7/2νf
7/2)7- isomer is estimated to be about 250keV, some 100keV lower than previously reported.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: anovak@fuw.edu.pl 相似文献
103.
A. Jungclaus K. P. Lieb C. J. Gross J. Heese D. Rudolph D. J. Blumenthal P. Chowdhury P. J. Ennis C. J. Lister Ch. Winter J. Eberth S. Skoda M. A. Bentley W. Gelletly B. J. Varley 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(2):125-139
High spin states in the transitional nucleus87Nb up to 14 MeV excitation have been established for the first time via the reactions40Ca(50Cr, 3p)87Nb and58Ni (32S, 3p)87Nb. The87Nbγ-radiations have been identified throughγ-ray spectra taken in coincidence with the evaporation residues detected in the Daresbury recoil separator or with multiple proton emission. Gamma-gamma coincidences, DCO ratios,γ-ray angular distributions and lifetimes have been measured. A total of some 100 transitions have been placed into a level scheme comprising of sixty states. The one-quasiparticle (1qp) bands of either parity and several other band-like structures have been identified, some containing alignedg 9/2 nucleons. Moderately enhancedE2 in-band transitions of 13–48 W.u. as well as several weakE2 yrast transitions connecting bands with different quasiparticle numbers have been found. Similarities with respect to theN=46 isotones83Rb,84Sr,85Y,86Zr and88Mo are discussed. 相似文献
104.
Fischer SM Lister CJ Balamuth DP Bauer R Becker JA Bernstein LA Carpenter MP Durell J Fotiades N Freeman SJ Garrett PE Hausladen PA Janssens RV Jenkins D Leddy M Ressler J Schwartz J Svelnys D Sarantites DG Seweryniak D Varley BJ Wyss R 《Physical review letters》2001,87(13):132501
The ground state rotational bands of the N = Z nuclei (72)Kr, (76)Sr, and (80)Zr have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. (72)Kr shows the most marked effect. It has been widely suggested that these "delayed alignments" arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation. 相似文献
105.
C. J. Gross J. Heese K. P. Lieb L. Lühmann B. Wörmann A. A. Chishti W. Gelletly C. J. Lister J. H. McNeill B. J. Varley 《Zeitschrift für Physik A Hadrons and Nuclei》1988,331(3):361-362
Yrast states with spins as high as 22 ? have been identified in76Kr with the reactions58Ni(24Mg,α2p) at 110 MeV and40Ca (40Ca, 4p) at 155 MeV. Simultaneous band crossings due to g9/2 proton and neutron quasiparticles have been observed in the frequency range 0.60≦?ω≦0.75 MeV. The moment of inertia increases rapidly at the crossing frequency. The systematics of proton and neutron alignments in the Kr isotopes are discussed. 相似文献
106.
R. L. Varley 《Journal of statistical physics》1979,21(1):87-100
The existing derivations of the Percus-Yevick equation are not readily extendable into the nonequilibrium domain. In particular, the elegant Percus functional construction relies on a test particle theorem which lacks an exact nonequilibrium generalization. We propose here a new construction which utilizes some elementary ideas of functional expansions together with the equilibrium BBGKY hierarchy of equations. Also, we feel this new construction provides fresh insight into the physical basis of the equilibrium Percus-Yevick equation.This research was supported in part by a grant from the Faculty Research Award Program of the City University of New York. 相似文献
107.
The induced force method developed by Mazur and Bedeaux is applied here to two-dimensional Brownian motion. We obtain a generalized Faxén theorem which reduces to the Stokes-Basset drag force on a nonuniformly moving cylinder or disk in the special case where the fluid fluctuations are neglected. The resulting modified Langevin equation is solved numerically for the velocity autocorrelation Ø(t) and the expected long time result Ø(t)~1/t is obtained. It is perhaps surprising that the short time behavior of Ø(t) deviates considerably from that predicted on the basis of a modified Langevin equation incorporating the classic Oseen-Lamb drag force on a cylinder. 相似文献
108.
The characteristic feature of the wide variety of hydraulic shear flows analyzed in this study is that they all contain a critical level where some of the fluid is turned relative to the ambient flow. One example is the flow produced in a thin layer of fluid, contained between lateral boundaries, during the passage of a long eddy. The boundaries of the layer may be rigid, or flexible, or free; the fluid may be either compressible or incompressible. A further example is the flow produced when a shear layer separates from a rigid boundary producing a region of recirculating flow. The equations used in this study are those governing inviscid hydraulic shear flows. They are similar in form to the classical boundary layer equations with the viscous term omitted. The main result of the study is to show that when the hydraulic flow is steady and contained between lateral boundaries, the variation of vorticity ω(ψ) cannot be prescribed at any streamline which crosses the critical level. This variation is, in fact, determined by (1) the vorticity distribution at all streamlines which do not cross the critical level, by (2) the auxiliary conditions which must be satisfied at the boundaries of the fluid layer, and by (3) the dimensions of the region containing the turned flow. If at some instant the vorticity distribution is specified arbitrarily at all streamlines, generally the subsequent flow will be unsteady. In order to emphasize this point, a class of exact solutions describing unsteady hydraulic flows are derived. These are used to describe the flow produced by the passage of a long eddy which distorts as it is convected with the ambient flow. They are also used to describe the unsteady flow that is produced when a shear layer separates from a boundary. Examples are given both of flows in which the shear layer reattaches after separation and of flows in which the shear layer does not reattach. When the shear layer vorticity distribution has the form ωαyn, where y is a distance measure across the layer, the steady flows are of Falkner-Skan type inside, and adjacent to, the separation region. The unsteady flows described in this paper are natural generalizations of these Falkner-Skan flows. One important result of the analysis is to show that if the unsteady flow inside the separation region is strongly sheared, then the boundary of the separation region moves upstream towards the point of separation, forming large transverse currents. Generally, the assumption of hydraulic flow becomes invalid in a finite time. On the other hand, if the flow inside the separation region is weakly sheared, this region is swept downstream and the flow becomes self-similar. 相似文献
109.
Stephen Fletcher Victoria Jane Black Iain Kirkpatrick Thomas Stephen Varley 《Journal of Solid State Electrochemistry》2013,17(2):327-337
In many modern technologies (such as batteries and supercapacitors), there is a strong need for redox-stable ionic liquids. Experimentally, the stability of ionic liquids can be quantified by the voltage range over which electron tunneling does not occur, but so far, quantum theory has not been applied systematically to this problem. Here, we report the electrochemical reduction of a series of quaternary ammonium cations in the presence of bis(trifluoromethylsulfonyl)imide (TFSI) anions and use nonadiabatic electron transfer theory to explicate the results. We find that increasing the chain length of the alkyl groups confers improved chemical inertness at all accessible temperatures. Simultaneously, decreasing the symmetry of the quaternary ammonium cations lowers the melting points of the corresponding ionic liquids, in two cases yielding highly inert solvents at room temperature. These are called hexyltriethylammonium TFSI (HTE-TFSI) and butyltrimethylammonium TFSI (BTM-TFSI). Indeed, the latter are two of the most redox-stable solvents in the history of electrochemistry. To gain insight into their properties, very high precision electrical conductivity measurements have been carried out in the range +20 °C to +190 °C. In both cases, the data conform to the Vogel-Tammann-Fulcher (VTF) equation with “six nines” precision (R 2?>?0.999999). The critical temperature for the onset of conductivity coincides with the glass transition temperature T g. This is compelling evidence that ionic liquids are, in fact, softened glasses. Finally, by focusing on the previously unsuspected connection between the molecular degrees of freedom of ionic liquids and their bulk conductivities, we are able to propose a new theory of the glass transition. This should have utility far beyond ionic liquids, in areas as diverse as glassy metals and polymer science. 相似文献