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A simple high-performance liquid chromatography (HPLC) method coupled with principal component analysis (PCA) and hierarchical cluster analysis (HCA) was developed for distinguishing Astragali Radix from its adulterants. Five species, including A. membranaceus var. mongolicus, A. membranaceus, H. polybotrys, A. chrysopterus and A. ernestii, were analyzed by this method. At the same time, four major bioactive isoflavonoids, namely calycosin-7-O-D-glucopyranoside, ononin, calycosin and formononetin, were simultaneously determined in Astragali Radix. This method was proven to have good precision, repeatability, stability and recovery. It was successfully applied to distinguish Astragali Radix from its adulterants species and can be used for the quality control of Astragali Radix [ABSTRACT FROM AUTHOR]

Using an isospin- and momentum-dependent transport model, we examine the effects of an electric field induced by a variable magnetic field on the π-/π+ ratio in central to peripheral heavy-ion collisions at beam energies of 400 and 1500 MeV/nucleon. It is shown that while the induced electric field does not affect the total multiplicities of both π- and π+ mesons at both the lower beam energy of 400 MeV/nucleon and the higher beam energy of 1500 MeV/nucleon, it reduces (enhances) the emission of π-(π+) mesons in midrapidity, but enhances (reduces) the emission of π-(π+) mesons in forward and backward rapidities especially for the more peripheral collisions at the lower beam energy because of the rapidly transient variable magnetic field at more peripheral collisions and the longer reaction duration time at the lower beam energy. These findings indicate that the total π-/π+ ratio is still a precisely reliable probe of symmetry energy at both the lower and the higher beam energies, but one should consider the induced electric field when using the differential π-/π+ ratio to probe the symmetry energy especially for the lower beam energy and more peripheral collisions. Finally, the relative suppression factor based on the ratio of π-/π+ in different rapidities is proposed to be an effective probe of the induced electric field generated in heavy-ion collisions due to its maximizing effects of induced electric fields on the differential π-/π+ ratio but minimizing effects of some uncertainty factors in heavy-ion collisions. [ABSTRACT FROM AUTHOR]

Within an improved transport model, we examine effects of the high momentum tail of the nucleon momentum distribution induced by short-range correlations on the proton-proton momentum correlation function in 197Au+197Au collisions at 400 MeV/nucleon. It is found that the proton-proton momentum correlation function from preequilibrium emissions responds sensitively to the presence as well as fraction of nucleons in the high momentum tail of the nucleon momentum distribution but is almost robustly insensitive to other factors, including the symmetry energy and the uncertainty of cutoff value of nucleon effective high momentum. In terms of the sensitivity and clearness, we propose that the proton-proton momentum correlation function from preequilibrium emissions can be as an effective probe of the high momentum tail of the nucleon momentum distribution. [ABSTRACT FROM AUTHOR]

Within the isospin- and momentum-dependent transport model IBUU11, we examine the relativistic retardation effects of electrical fields on the π-/π+ ratio and neutron-proton differential transverse flow in heavy-ion collisions at intermediate energies. Compared to the static Coulomb fields, the retarded electric fields of fast-moving charges are known to be anisotropic and the associated relativistic corrections can be significant. They are found to increase the number of energetic protons in the participant region at the maximum compression by as much as 25% but that of energetic neutrons by less than 10% in 197Au+197Au reactions at a beam energy of 400 MeV/nucleon. Consequently, more π+ and relatively fewer π- mesons are produced, leading to an appreciable reduction of the π-/π+ ratio compared to calculations with the static Coulomb fields. Also, the neutron-proton differential transverse flow, as another sensitive probe of high-density symmetry energy, is also decreased appreciably due to the stronger retarded electrical fields in directions perpendicular to the velocities of fast-moving charges compared to calculations using the isotropic static electrical fields. Moreover, the retardation effects on these observables are found to be approximately independent of the reaction impact parameter. [ABSTRACT FROM AUTHOR]