Permanence and extinction analysis for a delayed periodic predator-prey system with Holling type II response function and diffusion

In this paper, it is studied that two species predator-prey Lotka-Volterra type dispersal system with delay and Holling type II response function, in which the prey species can disperse among n patches, while the density-independent predator species is confined to one of the patches and cannot disperse. Sufficient conditions of integrable form for the boundedness, permanence, extinction and the existence of positive periodic solution are established, respectively.     

Analysis of mathematics and dynamics in a food web system with impulsive perturbations and distributed time delay

In this paper, on the basis of the theories and methods of ecology and ordinary differential equation, a food web system with impulsive perturbations and distributed time delay is established. By using the theories of impulsive equation, small amplitude perturbation skills and comparison technique, we get the condition which guarantees the global asymptotical stability of the prey and intermediate predator eradication periodic solution. On this basis, we get that the food web system is permanent if some parameters are satisfied with certain conditions. In order to show that these conditions are effective, the influences of impulsive perturbations on the inherent oscillation and distributed time delay are studied numerically; these show rich dynamics, such as period-halving bifurcation, chaotic band, narrow or wide periodic window, chaotic crises. Moreover, the computation of the largest Lyapunov exponent shows the chaotic dynamic behavior of the model. Meanwhile, we investigate the qualitative nature of strange attractor by using Fourier spectra. All of these results may be useful in the study of the dynamic complexity of ecosystems.     

硒化壳聚糖诱导NB4细胞凋亡及周期阻断作用

为研究硒化壳聚糖对NB4细胞的凋亡及周期阻断作用,用流式细胞法观察了药物对细胞的诱导凋亡及周期阻断作用。结果表明,硒化壳聚糖作用NB4细胞24 h,可剂量依赖性地诱导细胞凋亡并使G0—G1期细胞增多。提示硒化壳聚糖可诱导细胞凋亡,并对NB4细胞周期有特异性阻断作用。     

酱香型酒香气成分研究：1.珍酒,茅台酒空杯香分离及官能色谱探索

本文系统地研究了酱香型酒主体香的分离方法，摸索出“溶剂萃取－自然挥发－溶解”的酱香型酒空杯香的分离方法，首次从珍酒、茅台酒中分离出典型的空杯香。用在线色谱闻香系统研究了酱香型酒空杯香的化学成分，同时进行色谱测定及嗅闻。结果表明，空杯香是多种成分构成的复合香。     

酱香型酒香气成分研究：2.珍酒,茅台酒空杯香成分的GC／MS分析

用色质联用（ＧＣ／ＭＳ）法测定酱香型酒空杯香的化学成分，鉴定出１３种化合物，并测定了它们的相对含量，其中以十六酸乙酯、油酸乙酯、亚油酸乙酯为主。     

On the boundedness of solutions to the Lorenz-like family of chaotic systems

This paper deals with a class of three-dimensional autonomous nonlinear systems which have potential applications in secure communications, and investigates the localization problem of compact invariant sets of a class of Lorenz-like chaotic systems which contain T system with the help of iterative theorem and Lyapunov function theorem. Since the Lorenz-like chaotic system does not have y in the second equation, the approach used to the Lorenz system cannot be applied to the Lorenz-like chaotic system. We overcome this difficulty by introducing a cross term and get an interesting result, which includes the most interesting case of the chaotic attractor of the Lorenz-like systems. Furthermore, the results obtained in this paper are applied to study complete chaos synchronization. Finally, numerical simulations show the effectiveness of the proposed scheme.     

γ射线辐照超细铂催化剂的载体效应

用γ射线辐射法制备了铂溶胶和粒径为５ｎｍ的超细铂粉,采用机械混合法和溶胶－凝胶法制备了一系列不同载体的超细铂催化剂,不同载体对提高ＣＯ氧化活性的顺序为：ＭｇＯ〉γ－Ａｌ２Ｏ３≥ＺｒＯ２〉ＴｉＯ２〉ＳｉＯ２,其中,由溶胶－凝胶法制备的０．１％Ｐｔ／ＳｉＯ２和０．１％Ｐｔ／ＴｉＯ２的经表面积大,Ｐｔ分散度高,但活性最差,ＸＰＳ结果表明部分表面Ｐｔ＾０和ＴｉＯ２作用生成了ＰｔＯ和Ｔｉ２Ｏ３,并且Ｐｔ的分     

Research on Changes of Focusing Structure Parameters Caused by the DC-Clearing Electric Field of Storage Ring

The changes of focusing structure parameters caused by the DC-clearing electric field of storage ring were researched. The conclusion is made that tune shift caused by the DC-clearing electric field is related to the real-time close orbit of stored beam. The clearing electric field asymmetrically distributed along the ring destroys the symmetry of the focusing structure and decreases the acceptance of storage ring. It has negative effect to the injection and accumulation process in certain condition.