607 research outputs found
Coherent control of enrichment and conversion of molecular spin isomers
A theoretical model of nuclear spin conversion in molecules controlled by an
external electromagnetic radiation resonant to rotational transition has been
developed. It has been shown that one can produce an enrichment of spin isomers
and influence their conversion rates in two ways, through coherences and
through level population change induced by radiation. Influence of conversion
is ranged from significant speed up to almost complete inhibition of the
process by proper choice of frequency and intensity of the external field.Comment: REVTEX, 13 pages + 6 eps figure
An ISFET-based anion sensor for the potentiometric detection of organic acids in liquid chromatography
An ion-selective field effect transistor (ISFET) was applied as a potentiometric detector in liquid chromatography (LC) for the determination of organic acids. The ISFET was prepared by coating the gate insulator of the encapsulated transistor with a poly(vinyl chloride) (PVC) matrix membrane containing methyltridodecylammoniumchloride, which enables the detection of organic anions. The ISFET was tested for its applicability as detector for carboxylic acids in ion-exchange and reversed-phase chromatography. Its analytical characteristics were compared to those of a coated-wire electrode (CWE) and of a conventional type of ion-selective electrode (ISE)
Brueckner Rearrangement Effects in He and He
Rearrangement effects in light hypernuclei are investigated in the framework
of the Brueckner theory. We can estimate without detailed numerical
calculations that the energy of the -core is reduced by more than 2.5
MeV when the adheres to He to form He. Similar
assessment of rearrangement contributions is essential to deduce the strength
of interaction from experimentally observed . The recently observed experimental value of 1 MeV
for the of \hll suggests that the matrix element of
in \hll is around -2 MeV.Comment: 7 pages, to appear in Phys. Rev.
ESC NN-Potentials in Momentum Space. I. PS-PS Exchange Potentials
A momentum space representation is derived for the Nijmegen
Extended-Soft-Core (ESC) interactions. The partial wave projection of this
representation is carried through, in principle for Two-Meson-Exchange (TME) in
general. Explicit results for the momentum space partial wave NN-potentials
from PS-PS-Exchange are given.Comment: 23 pages, 2 PostScript figures, revtex
Lambda-proton correlations in relativistic heavy ion collisions
The prospect of using lambda-proton correlations to extract source sizes in
relativistic heavy ion collisions is investigated. It is found that the strong
interaction induces a large peak in the correlation function that provides more
sensitive source size measurements than two-proton correlations under some
circumstances. The prospect of using lambda-proton correlations to measure the
time lag between lambda and proton emissions is also studied.Comment: 4 pages, 3 figure, revtex style. Two short paragraphs are added at
referees' recommendations. Phys. Rev. Lett. in pres
Comment on Neutron-Proton Spin-Correlation Parameter A_{ZZ} at 68 Mev
We present two arguments indicating that the large value for the
mixing parameter at 50 MeV, which the Basel group extracted from their recent
measurement, may be incorrect. First, there are nucleon-nucleon (NN)
potentials which predict the at 50 MeV substantially below the
Basel value and reproduce the Basel data accurately. Second, the large
value for at 50 MeV proposed by the Basel group can only be
explained by a model for the NN interaction which is very unrealistic (no
-meson and essentially a point-like vertex) and overpredicts the
in the energy range where it is well determined (150--500 MeV) by
a factor of two.Comment: 6 pages text (LaTex) and 2 figures (paper, will be faxed upon
request), UI-NTH-930
Self-Referential Noise and the Synthesis of Three-Dimensional Space
Generalising results from Godel and Chaitin in mathematics suggests that
self-referential systems contain intrinsic randomness. We argue that this is
relevant to modelling the universe and show how three-dimensional space may
arise from a non-geometric order-disorder model driven by self-referential
noise.Comment: Figure labels correcte
Energy level displacement of the excited nl state of pionic hydrogen
The energy level displacements of the excited nl states of pionic hydrogen
and the contribution of the ns -> 1s transitions and the (pi^-p)_Coul -> 1s
transitions of the pi^-p pair, coupled by the attractive Coulomb field in the
S-wave state with a continuous energy spectrum, to the shift of the energy
level of the ground state of pionic hydrogen, caused by strong low-energy
interactions, are calculated within a quantum field theoretic, relativistic
covariant and model-independent approach developed in nucl-th/0306047.Comment: 18 pages, no figures, latex, text is revised, references are adde
Measuring the gluon spin in protons through central production
The investigation of a proposed glueball filter in proton-proton collisions
led us to show that its action is in fact easily understood in terms of
kinematics. While the procedure proposed stays of interest in reducing
background when lookingfor centrally produced resonances of specified spin and
parity, we stress that it can be put to advantage in giving access to the
polarization of gluons in the inital protonsComment: talk presented at QCD98, Montepellier. to appear in proceeding
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