5,327 research outputs found
Hydrogen isotope exchange in proton-conducting oxides during proton and deuteron irradiation
It has been found that during accelerator beam deuteron irradiation of a proton-conducting oxide containing protium H/D isotope exchange between beam ions and dissolved ions takes place. This isotope exchange was also observed during high-energy proton irradiation of the oxide containing dissolved deuterium atoms. These results provide evidence to a new type of hydrogen isotope exchange. Any appreciable effects of conjugate diffusion of hydrogen and oxygen ions and of the interface processes on the isotope exchange rate were eliminated. In this type of exchange the rate of replacement of H+ by D+ and of D+ by H+ was determined only by the properties of the crystal. The discovered effect was used in our study to obtain experimental data characterizing the dynamic and equilibrium behavior of hydrogen isotopes in the oxide BaZr0.9Y0.1O3 - δ. © 2013 Pleiades Publishing, Ltd
Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V
The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and
46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8),
6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are
substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table
Isomeric states close to doubly magic Sn studied with JYFLTRAP
The double Penning trap mass spectrometer JYFLTRAP has been employed to
measure masses and excitation energies for isomers in Cd,
Cd, Cd and Te, for isomers in In and
In, and for isomers in Sn and Sb. These first
direct mass measurements of the Cd and In isomers reveal deviations to the
excitation energies based on results from beta-decay experiments and yield new
information on neutron- and proton-hole states close to Sn. A new
excitation energy of 144(4) keV has been determined for Cd. A good
agreement with the precisely known excitation energies of Cd,
Sn, and Sb has been found.Comment: 10 pages, 6 figures, submitted to Phys. Rev.
Mass measurements in the vicinity of the doubly-magic waiting point 56Ni
Masses of 56,57Fe, 53Co^m, 53,56Co, 55,56,57Ni, 57,58Cu, and 59,60Zn have
been determined with the JYFLTRAP Penning trap mass spectrometer at IGISOL with
a precision of dm/m \le 3 x 10^{-8}. The QEC values for 53Co, 55Ni, 56Ni, 57Cu,
58Cu, and 59Zn have been measured directly with a typical precision of better
than 0.7 keV and Coulomb displacement energies have been determined. The Q
values for proton captures on 55Co, 56Ni, 58Cu, and 59Cu have been measured
directly. The precision of the proton-capture Q value for 56Ni(p,gamma)57Cu,
Q(p,gamma) = 689.69(51) keV, crucial for astrophysical rp-process calculations,
has been improved by a factor of 37. The excitation energy of the proton
emitting spin-gap isomer 53Co^m has been measured precisely, Ex = 3174.3(10)
keV, and a Coulomb energy difference of 133.9(10) keV for the 19/2- state has
been obtained. Except for 53Co, the mass values have been adjusted within a
network of 17 frequency ratio measurements between 13 nuclides which allowed
also a determination of the reference masses 55Co, 58Ni, and 59Cu.Comment: 14 pages, 13 figures, submitted to Phys. Rev.
Faddeev study of heavy baryon spectroscopy
We investigate the structure of heavy baryons containing a charm or a bottom
quark. We employ a constituent quark model successful in the description of the
baryon-baryon interaction which is consistent with the light baryon spectra. We
solve exactly the three-quark problem by means of the Faddeev method in
momentum space. Heavy baryon spectrum shows a manifest compromise between
perturbative and nonperturbative contributions. The flavor dependence of the
one-gluon exchange is analyzed. We assign quantum numbers to some already
observed resonances and we predict the first radial and orbital excitations of
all states with or 3/2. We combine our results with heavy quark
symmetry and lowest-order SU(3) symmetry breaking to predict the masses and
quantum numbers of six still non-measured ground-state beauty baryons.Comment: 22 pages, 4 figures, 8 tables. Accepted for publication in J. Phys.
Binding of molecules to DNA and other semiflexible polymers
A theory is presented for the binding of small molecules such as surfactants
to semiflexible polymers. The persistence length is assumed to be large
compared to the monomer size but much smaller than the total chain length. Such
polymers (e.g. DNA) represent an intermediate case between flexible polymers
and stiff, rod-like ones, whose association with small molecules was previously
studied. The chains are not flexible enough to actively participate in the
self-assembly, yet their fluctuations induce long-range attractive interactions
between bound molecules. In cases where the binding significantly affects the
local chain stiffness, those interactions lead to a very sharp, cooperative
association. This scenario is of relevance to the association of DNA with
surfactants and compact proteins such as RecA. External tension exerted on the
chain is found to significantly modify the binding by suppressing the
fluctuation-induced interaction.Comment: 15 pages, 7 figures, RevTex, the published versio
The level of somatic health, sports specialization and qualification of an athlete as indicators of intermediate selection in the mixed martial arts
This article presents the results of experimental research to identify high-priority types of martial arts whose representatives successfully implement their skills in mixed martial arts, as well as the results of the study of somatic healt
Pentaquarks: review of the experimental evidence
Pentaquarks, namely baryons made by 4 quarks and one antiquark have been
predicted and searched for since several decades without success. Theoretical
and experimental advances in the last 2 years led to the observation of a
number of pentaquark candidates. We review the experimental evidence for
pentaquarks as well as their non-observations by some experiments, and discuss
to which extend these sometimes contradicting informations may lead to a
consistent picture.Comment: Contribution to the International Conference on 'Strangeness in Quark
Matter', 15-21 Sept. 2004, Cape Tawn, South Afric
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