The effect of surface and Coulomb interaction on the liquid-gas phase transition of finite nuclei

By means of the Furnstahl, Serot and Tang's model, the effects of surface tension and Coulomb interaction on the liquid-gas phase transition for finite nuclei are investigated. A limit pressure p-lim above which the liquid-gas phase transition cannot take place has been found. It is found that comparing to the Coulomb interaction, the contribution of surface tension is dominate in low temperature regions. The binodal surface is also addressed.Comment: LaTex, 8 pages with 6 fig

Lightest scalars as chiral partners of the Nambu--Goldstone bosons

We review the spectrum of lightest scalar resonances recently determined using dispersion techniques. The conceptual difference between the pole mass and the bare mass (or the line--shape mass) is stressed. The nature of the lightest scalars are discussed and we argue, without relying on any model details, that the $\sigma(500)$, $\kappa(700)$, $a_0(980)$ and $f_0(980)$ may be understood as chiral partners of the Nambu--Goldstone bosons in the linear realization of chiral symmetry. But there remains some difficulties in understanding the role of $f_0(980)$ in this picture.Comment: Invited talk given by Zheng at QCD06, Montpellier, France, July 3--7, 200

Anomalous normal mode oscillations in semiconductor microcavities

Semiconductor microcavities as a composite exciton-cavity system can be characterized by two normal modes. Under an impulsive excitation by a short laser pulse, optical polarizations associated with the two normal modes have a {pi} phase difference. The total induced optical polarization is then expected to exhibit a sin{sup 2}({Omega}t)-like oscillation where 2{Omega} is the normal mode splitting, reflecting a coherent energy exchange between the exciton and cavity. In this paper the authors present experimental studies of normal mode oscillations using three-pulse transient four wave mixing (FWM). The result reveals surprisingly that when the cavity is tuned far below the exciton resonance, normal mode oscillation in the polarization is cos{sup 2}({Omega}t)-like, in contrast to what is expected form the simple normal mode model. This anomalous normal mode oscillation reflects the important role of virtual excitation of electronic states in semiconductor microcavities

Stimulated emission from semiconductor microcavities

Laser-like emissions from semiconductor microcavities at low temperature have attracted considerable attention recently because of the possibility of realizing a non-equilibrium condensate by using cavity-polaritons. In this paper the authors present experimental studies of optical properties of a microcavity near the lasing threshold. They show that the minimum lasing threshold is achieved when the cavity is tuned significantly below the exciton line center. By comparing emission spectra with reflectivity spectra, they also show that well-resolved doublet in the emission spectra near the lasing threshold are not associated with cavity-polaritons. These results suggest that laser-like emissions form the microcavity are due to conventional stimulated emission processes with exciton localization playing a significant role

A Statistical Study on Photospheric Magnetic Nonpotentiality of Active Regions and Its Relationship with Flares during Solar Cycles 22-23

A statistical study is carried out on the photospheric magnetic nonpotentiality in solar active regions and its relationship with associated flares. We select 2173 photospheric vector magnetograms from 1106 active regions observed by the Solar Magnetic Field Telescope at Huairou Solar Observing Station, National Astronomical Observatories of China, in the period of 1988-2008, which covers most of the 22nd and 23rd solar cycles. We have computed the mean planar magnetic shear angle (\bar{\Delta\phi}), mean shear angle of the vector magnetic field (\bar{\Delta\psi}), mean absolute vertical current density (\bar{|J_{z}|}), mean absolute current helicity density (\bar{|h_{c}|}), absolute twist parameter (|\alpha_{av}|), mean free magnetic energy density (\bar{\rho_{free}}), effective distance of the longitudinal magnetic field (d_{E}), and modified effective distance (d_{Em}) of each photospheric vector magnetogram. Parameters \bar{|h_{c}|}, \bar{\rho_{free}}, and d_{Em} show higher correlation with the evolution of the solar cycle. The Pearson linear correlation coefficients between these three parameters and the yearly mean sunspot number are all larger than 0.59. Parameters \bar{\Delta\phi}, \bar{\Delta\psi}, \bar{|J_{z}|}, |\alpha_{av}|, and d_{E} show only weak correlations with the solar cycle, though the nonpotentiality and the complexity of active regions are greater in the activity maximum periods than in the minimum periods. All of the eight parameters show positive correlations with the flare productivity of active regions, and the combination of different nonpotentiality parameters may be effective in predicting the flaring probability of active regions.Comment: 20 pages, 5 figures, 4 tables, accepted for publication in Solar Physic

An improved study of the kappa resonance and the non-exotic ss wave πK\pi K scatterings up to s=2.1\sqrt{s}=2.1GeV of LASS data

We point out that the dispersion relation for the left hand cut integral presented in one of our previous paper (Nucl. Phys. {\bf A}733(2004)235) is actually free of subtraction constant, even for unequal mass elastic scatterings. A new fit to the LASS data~\cite{Aston} is performed and firm evidence for the existence of $\kappa$ pole is found. The correct use of analyticity also put strong constraints on threshold parameters -- which are found to be in good agreement with those obtained from chiral theories. We also determined the pole parameters of $K_0^*(1430)$ on the second sheet, and reconfirm the existence of $K_0^*(1950)$ on the third sheet. We stress that the LASS data do not require them to have the twin pole structure of a typical Breit--Wigner resonance.Comment: 14 pages + 4 postscript figures; discussions largely expanded; references added; version to appear in NPA; title changed in the journa

Genome-wide association study for Atopy and Allergic Rhinitis in a Singapore Chinese population

10.1371/journal.pone.0019719PLoS ONE65

A self-consistent method to analyze the effects of the positive Q-value neutron transfers on fusion

AbstractConsidering the present limitation of the need for external parameters to describe the nucleus–nucleus potential and the couplings in the coupled-channels calculations, this work introduces an improved method without adjustable parameter to overcome the limitation and then sort out the positive Q-value neutron transfers (PQNT) effects based on the CCFULL calculations. The corresponding analysis for Ca+Ca, S,Ca+Sn, and S,Ca+Zr provides a reliable proof and a quantitative evaluation for the residual enhancement (RE) related to PQNT. In addition, the RE for S32,Ca40+Zr94 shows an unexpected larger enhancement than S32,Ca40+Zr96 despite the similar multi-neutron transfer Q-values. This method should rather strictly test the fusion models and be helpful for excavating the underlying physics

Electrochemical capacitance of a leaky nano-capacitor

We report a detailed theoretical investigation on electrochemical capacitance of a nanoscale capacitor where there is a DC coupling between the two conductors. For this ``leaky'' quantum capacitor, we have derived general analytic expressions of the linear and second order nonlinear electrochemical capacitance within a first principles quantum theory in the discrete potential approximation. Linear and nonlinear capacitance coefficients are also derived in a self-consistent manner without the latter approximation and the self-consistent analysis is suitable for numerical calculations. At linear order, the full quantum formula improves the semiclassical analysis in the tunneling regime. At nonlinear order which has not been studied before for leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge show interesting behavior. Our theory allows the investigation of crossover of capacitance from a full quantum to classical regimes as the distance between the two conductors is changed

Towards the Understanding of Chinese Collaboration in Hospitality – The Opinions of Professionals

The increasingly competitive market in China has resulted in the struggle of hotels for competitive advantage, and even for survival. Among the possible tools to rise above this cut-throat environment is the concept of hotel collaboration. This paper moves towards the understanding of hotel collaboration in China based on the focus group discussions of 22 experienced practitioners in the Chinese hotel and related industries. The data identified several threats, opportunities, and insights into hotel collaboration of domestic with overseas hotels as well as predictions for the future of this practice in China. Based on specific cultural, political, and economic contexts of contemporary China, the results indicate that partial collaboration is likely to succeed in the hotel market of the country