53,916 research outputs found
An exact solution of spherical mean-field plus orbit-dependent non-separable pairing model with two non-degenerate j-orbits
An exact solution of nuclear spherical mean-field plus orbit-dependent
non-separable pairing model with two non-degenerate j-orbits is presented. The
extended one-variable Heine-Stieltjes polynomials associated to the Bethe
ansatz equations of the solution are determined, of which the sets of the zeros
give the solution of the model, and can be determined relatively easily. A
comparison of the solution to that of the standard pairing interaction with
constant interaction strength among pairs in any orbit is made. It is shown
that the overlaps of eigenstates of the model with those of the standard
pairing model are always large, especially for the ground and the first excited
state. However, the quantum phase crossover in the non-separable pairing model
cannot be accounted for by the standard pairing interaction.Comment: 5 pages, 1 figure, LaTe
Synthesis, Structure and Magnetic Properties of New Layered Iron-Oxychalcogenide Na2Fe2OSe2
A new layered iron-oxychalcogenide Na2Fe2OSe2 has been synthesized and
structurally characterized by powder X-ray diffraction. The structure is formed
by alternate stacking of the newly discovered [Fe2OSe2] blocks and double
layers of Na. Conductivity study shows that Na2Fe2OSe2 is a semiconductor with
activation energy of 0.26 eV. Magnetic susceptibility and heat capacity
measurements reveal an antiferromagnetic phase transition occurs at TN=73 K. A
broad maximum of magnetic susceptibility and a slow decay of the specific heat
above TN, arises as a result of two-dimensional short-range spin correlation.Comment: 4 pages, 4 figure
Bolstering cholesteryl ester hydrolysis in liver: A hepatocyte-targeting gene delivery strategy for potential alleviation of atherosclerosis
Current atherosclerosis treatment strategies primarily focus on limiting further cholesteryl esters (CE) accumulation by reducing endogenous synthesis of cholesterol in the liver. No therapy is currently available to enhance the removal of CE, a crucial step to reduce the burden of the existing disease. Given the central role of hepatic cholesteryl ester hydrolase (CEH) in the intrahepatic hydrolysis of CE and subsequent removal of the resulting free cholesterol (FC), in this work, we applied galactosefunctionalized polyamidoamine (PAMAM) dendrimer generation 5 (Gal-G5) for hepatocyte-specific delivery of CEH expression vector. The data presented herein show the increased specific uptake of Gal-G5/CEH expression vector complexes (simply Gal-G5/CEH) by hepatocytes in vitro and in vivo. Furthermore, the upregulated CEH expression in the hepatocytes significantly enhanced the intracellular hydrolysis of high density lipoprotein-associated CE (HDL-CE) and subsequent conversion/secretion of hydrolyzed FC as bile acids (BA). The increased CEH expression in the liver significantly increased the flux of HDL-CE to biliary as well as fecal FC and BA. Meanwhile, Gal-G5 did not induce hepatic or renal toxicity. It was also not immunotoxic. Because of these encouraging pre-clinical testing results, using this safe and highly efficient hepatocyte-specific gene delivery platform to enhance the hepatic processes involved in cholesterol elimination is a promising strategy for the alleviation of atherosclerosis
Spin photocurrent, its spectra dependence, and current-induced spin polarization in an InGaAs/InAlAs two-dimensional electron gas
Converse effect of spin photocurrent and current induced spin polarization
are experimentally demonstrated in the same two-dimensional electron gas system
with Rashba spin splitting. Their consistency with the strength of the Rashba
coupling as measured from beating of the Shubnikov-de Haas oscillations reveals
a unified picture for the spin photocurrent, current-induced spin polarization
and spin orbit coupling. In addition, the observed spectral inversion of the
spin photocurrent indicates the system with dominating structure inversion
asymmetry.Comment: 13 pages, 4 figure
Ultrafast pump-probe spectroscopic signatures of superconducting and pseudogap phases in YBa2Cu3O7-{\delta} films
Femtosecond pump-probe spectroscopy is applied to identify transient optical
signatures of phase transitions in optimally doped YBa2Cu3O7-{\delta} films. To
elucidate the dynamics of superconducting and pseudogap phases, the slow
thermal component is removed from the time-domain traces of photo-induced
reflectivity in a high-flux regime with low frequency pulse rate. The rescaled
data exhibit distinct signatures of the phase separation with abrupt changes at
the onsets of TSC and TPG in excellent agreement with transport data. Compared
to the superconducting phase, the response of the pseudogap phase is
characterized by the strongly reduced reflectivity change accompanied by a
faster recovery time.Comment: 14 pages, 3 figure
Aharonov-Bohm phase operations on a double-barrier nanoring charge qubit
We present a scheme for charge qubit implementation in a double-barrier
nanoring. The logical states of the qubit are encoded in the spatial
wavefunctions of the two lowest energy states of the system. The Aharonov-Bohm
phase introduced by magnetic flux, instead of tunable tunnelings, along with
electric fields can be used for implementing the quantum gate operations.
During the operations, the external fields should be switched smoothly enough
to avoid the errors caused by the transition to higher-lying states. The
structure and field effects on the validity of the qubit are also studied.Comment: 6 pages, 7 figure
Dynamical behavior of interacting dark energy in loop quantum cosmology
The dynamical behaviors of interacting dark energy in loop quantum cosmology
are discussed in this paper. Based on defining three dimensionless variables,
we simplify the equations of the fixed points. The fixed points for interacting
dark energy can be determined by the Friedmann equation coupled with the
dynamical equations {in Einstein cosmology}. But in loop quantum cosmology,
besides the Friedmann equation, the conversation equation also give a constrain
on the fixed points. The difference of stability properties for the fixed
points in loop quantum cosmology and the ones in Einstein cosmology also have
been discussed.Comment: 7 pages, 5 figure
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