Reconstructing dark energy potentials from parameterized deceleration parameters

In this paper, the properties of dark energy are investigated according to the parameterized deceleration parameter q(z), which is used to describe the extent of the accelerating expansion of the universe. The potential of dark energy V(φ) and the cosmological parameters, such as the dimensionless energy density \varOmega_φ, \varOmega_m, and the state parameter w_φ, are connected to it. Concretely, by giving two kinds of parameterized deceleration parameters q(z)=a+bz/(1+z) and q(z)=1/2+(az+b)/(1+z)^2, the evolution of these parameters and the reconstructed potentials V(φ) are plotted and analysed. It is found that the potentials run away with the evolution of universe.     

Constraints on the unified model of dark matter and dark energy

Using recently observed data:the Constitution dataset of type supernovae Ia (SNIa),the observational Hubble data (OHD),the measurement results of baryon acoustic oscillation (BAO) from the Sloan Digital Sky Survey (SDSS) and the Two Degree Field Galaxy Redshift Survey (2dFGRS),and the current cosmic microwave background (CMB) data from the five-year Wilkinson Microwave Anisotropy Probe (WMAP),we apply the Markov Chain Monte Carlo method to investigate the observational constraints on the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy.For this unified model,the constraints on GCG mixture are discussed by considering the different expressions of current matter density or considering constraints as being independent of the matter quantity Ωm.     

可修复纤维损伤的防霜和防雾聚合物复合膜

聚合物材料内部具有的微/纳米尺度的结构赋予了它们独特的功能.然而，聚合物材料在使用时不可避免地会遭受机械损伤，这会使得聚合物材料的微/纳米结构受到破坏，导致聚合物材料自身功能的丧失.为了解决上述问题，我们利用聚丙烯酸(PAA)与聚丙烯酰胺(PAAm)的嵌段共聚物(PAA-b-PAAm)和聚二烯丙基二甲基氯化铵(PDDA)形成的复合物溶液，通过提拉成膜，然后在25℃、相对湿度为～100%的环境中退火处理，制备了可修复纳米纤维损伤的防霜和防雾聚合物复合膜(PAA-b-PAAm/PDDA).亲水的PAA-b-PAAm/PDDA膜的纳米纤维结构可以增加水滴和膜表面的接触面积并促进膜对水分子的快速吸收，从而赋予了该膜优异的防雾防霜性能.得益于聚合物链间静电与氢键作用的动态性，PAA-b-PAAm/PDDA膜具有优异的自修复性能，不仅能修复宽度为几十微米的划痕，还能使断裂的纤维重新连接并恢复其原有的纳米纤维结构.