Dispersion Relation of δ Meson and Pion at Finite Nuclear Density in Chiral δ Model

The propagators of pion and sigma meson at a finite nuclear density and zero temperature are studied in chiral σ model. Their dispersion relations are calculated numerically in one-loop approximation. In order to avoid the so-called tachyon pole appearing in the one-loop propagators of pion and sigma meson, we regard the mass of sigma meson mσ as a free parameter and adjust it to fit the nuclear saturation properties. For mσ equal to 3075 MeV, the tachyonpole does not appear at the normal nuclear density. Thus the dispersion relation can be calculated in chiral σ model in one-loop level for the first time.

MCU增强DC／DC转换器输出

卓越的DC／DC转换器离不开卓越的控制器。Spansion半导体的新技术利用MCU的数字处理能力成功缩减了组件的数量。它能够利用软件平台轻松灵活地满足系统要求．而且还能通过车载网络向驾驶员显示故障信息。从而简化了车辆的维护工作。