Triton-He-3 relative and differential flows as probes of the nuclear symmetry energy at supra-saturation densities

Using a transport model coupled with a phase-space coalescence afterburner, we study the triton-He-3 (t-He-3) ratio with both relative and differential transverse flows in semicentral Sn-132 + Sn-124 reactions at a beam energy of 400 MeV/nucleon. The neutron-proton ratios with relative and differential flows are also discussed as a reference. We find that similar to the neutron-proton pairs, the t-He-3 pairs also carry interesting information regarding the density dependence of the nuclear symmetry energy. Moreover, the nuclear symmetry energy affects more strongly the t-He-3 relative and differential flows than the pi(-)/pi(+) ratio in the same reaction. The t-He-3 relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

Differential isospin-fractionation in dilute asymmetric nuclear matter

The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the neutron/proton ratio of the gas phase becomes smaller than that of the liquid phase for energetic nucleons, although the gas phase is overall more neutron-rich. Clear indications of the differential IsoF consistent with the thermal model predictions are demonstrated within a transport model for heavy-ion reactions. Future comparisons with experimental data will allow us to extract critical information about the momentum dependence of the isovector strong interaction.

Double neutron-proton differential transverse flow as a probe for the high density behavior of the nuclear symmetry energy

The double neutron-proton differential transverse flow taken from two reaction systems using different isotopes of the same element is studied at incident beam energies of 400 and 800 MeV/nucleon within the framework of an isospin- and momentum-dependent hadronic transport model IBUU04. The double differential flow is found to retain about the same sensitivity to the density dependence of the nuclear symmetry energy as the single differential flow in the more neutron-rich reaction. Because the double differential flow reduces significantly both the systematic errors and the influence of the Coulomb force, it is thus more effective probe for the high-density behavior of the nuclear symmetry energy.

TRITON-(HE)-H-3 RELATIVE AND DIFFERENTIAL FLOWS AND THE HIGH DENSITY BEHAVIOR OF NUCLEAR SYMMETRY ENERGY

Using a transport model coupled with a phase-space coalescence after-burner we study the triton-He-3 relative and differential transverse flows in semi-central Sn-132 + Sn-124 reactions at a beam energy of 400 MeV/nucleon. We find that the triton-He-3 pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t-He-3 relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

Synthesis and characterization of chiral smectic side-chain liquid crystalline polysiloxanes and ionomers containing sulfonic acid groups

The synthesis of new chiral smectic A (S-A) side-chain liquid crystalline polysiloxanes (LCPs) and ionomers (LCIs) containing 4-allyloxy-benzoyl-4-(S-2-ethylhexanoyl) p-benzenediol his ate (ABB) as mesogenic units and 4-[[4-(2-propenyloxy)phenyl] azo]benzensulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are confirmed by FTIR spectroscopy or H-1-NMR. Differential scanning calorimetry (DSC), optical polarizing microscopy, and X-ray diffraction measurements reveal that all the polymers P-I-P-IV and ionomers P-V-P-VI exhibit S-A texture. The results seem to demonstrate that the tendency toward the S-A-phase region increases with increasing sulfonic acid concentration, and the thermal stability of the S-A phase is determined by the flexibility of the polymer backbones and the interactions of sulfonic acid groups. (C) 2001 John Wiley & Sons, Inc.

THE APPLICATION OF THE MPB4 THEORY TO THE INTERFACE BETWEEN 2 IMMISCIBLE ELECTROLYTE-SOLUTIONS .2. THE DIFFERENTIAL CAPACITANCE OF THE WATER 1,2-DICHLOROETHANE INTERFACE

The MPB4 theory is used to calculate the differential capacitance of the interface between LiCl in water and TBATPB in 1,2-dichloroethane at electrolyte concentrations of 0.005, 0.01 and 0.02 M. The effects of the ion size and the image force, and the influence of the electrolyte concentration, the surface charge density and the solvent effect on the inner layer potential drop are considered simultaneously. These effects can be ascribed to the ionic penetration into the opposite solution and ion-ion correlations across the interface. Our results are in better agreement with experimental data than those obtained using Gouy-Chapman theory. This indicates that the MPB4 theory may also describe the structure of the water \1,2-dichloroethane interface provided that the influence of the electrolyte concentration, the surface charge density and the solvent effect on the inner layer potential distribution are included in the calculation. Comparison of the theoretical results with those of the water \nitrobenzene interface shows that the structure of the water \1,2-dichloroethane interface is similar to that of the water \nitrobenzene interface, except that in the former case the inner-layer potential drop is much higher and the effects of the image force and the ion size are more pronounced.

THE APPLICATION OF THE MPB4 THEORY TO THE INTERFACE BETWEEN 2 IMMISCIBLE ELECTROLYTE-SOLUTIONS .1. THE DIFFERENTIAL CAPACITANCE OF THE WATER NITROBENZENE INTERFACE

We use the MPB4 theory to calculate the differential capacitance of the interface between NaBr + water and tetrabutylammoniumtetraphenyl borate (TBATPB) + nitrobenzene at electrolyte concentrations of 0.01 M, 0.02 M and 0.05 M. In addition to the effects

DETERMINATION OF THE MARK-HOUWINK EQUATION FOR CHITOSANS WITH DIFFERENT DEGREES OF DEACETYLATION

The values of k and alpha in the Mark-Houwink equation have been determined for chitosans with different degrees of deacetylation (DD) (69, 84, 91 and 100% respectively), in 0.2 M CH3COOH/0.1 M CH3COONa aqueous solution at 30-degrees-C by the light scattering method. It was shown that the values of alpha-decreased from 1.12 to 0.81 and the values of k increased from 0.104 x 10(-3) to 16.80 x 10(-3) ml/g, when the DD varied from 69 to 100%. This is due to a reduction of rigidity of the molecular chain and an increase of the electrostatic repulsion force of the ionic groups along the polyelectrolyte chain in chitosan solution, when the DD of chitosan increases gradually.