Controlled synthesis of dendritic ruthenium nanostructures under microwave irradiation and their catalytic properties for p-chloronitrobenzene hydrogenation

Transition Metal Chemistry - In this study, the shape-controlled synthesis of ruthenium (Ru) nanostructures was examined using microwave irradiation. Dendritic Ru nanostructures, with an average...     

有机膨润土负载ZnO/TiO2光降解催化剂的研制及性能

以六水硝酸锌、酞酸丁酯和有机膨润土为原料,采用沉淀法制备ZnO/TiO2膨润土复合光催化材料,用IR和XRD对光催化剂的组织构造和微观结构进行表征,实验了光催化剂对亚甲基蓝废水的降解性能。结果表明：ZnO/TiO2成功负载于膨润土片层表面,ZnO的含量为有机膨润土的8%,反应温度为70℃,焙烧温度为420℃,催化剂用量为12mg/L时,亚甲基蓝废水的降解率可达97%以上。     

Dynamics analysis of a delayed viral infection model with immune impairment

In this paper, the dynamical behavior of a delayed viral infection model with immune impairment is studied. It is shown that if the basic reproductive number of the virus is less than one, then the uninfected equilibrium is globally asymptotically stable for both ODE and DDE model. And the effect of time delay on stabilities of the equilibria of the DDE model has been studied. By theoretical analysis and numerical simulations, we show that the immune impairment rate has no effect on the stability of the ODE model, while it has a dramatic effect on the infected equilibrium of the DDE model.     

Mathematical model for the control of a pest population with impulsive perturbations on diseased pest

In this paper, a stage-structured pest management SI model with impulsive perturbations on infected pest is introduced. Sufficient conditions of the global attractivity of pest-extinction periodic solution and permanence of the system are obtained. We also prove that all solutions of system are uniformly ultimately bounded.     

硅杂苯与亲二烯体的Diels-Alder反应

采用密度泛函理论(DFT)在B3LYP/6-311G(d,p)水平上研究了硅杂苯与一些亲二烯体的两类可能的Diels-Alder反应的微观机理、势能剖面、取代基效应和溶剂化效应. 计算结果表明, 所研究反应均以协同的方式进行. 亲二烯体分子碳原子上的苯基取代基对两个新键形成的非同步性和反应的活化能垒的影响取决于苯基在产物中的相对位置, 而硅杂苯分子中硅原子上的CCl3取代基有利于杂Diels-Alder反应的进行. 形成一个C—Si键的杂Diels-Alder反应在热力学和动力学上均远比相应的全碳Diels-Alder反应容易进行, 实验观察到的杂Diels-Alder反应中的区域选择性由动力学因素所控制. 硅杂苯与烯烃的反应比与相应炔烃的反应在动力学上容易进行一些, 但在热力学上后者远比前者容易进行. 苯溶剂对所研究反应的势能剖面影响较小.     

The dynamics of an eco-epidemiological model with distributed delay

In this paper, the dynamical behavior of an eco-epidemiological model with distributed delay is studied. Sufficient conditions for the asymptotical stability of all the equilibria are obtained. We prove that there exists a threshold value of the conversion rate h beyond which the positive equilibrium bifurcates towards a periodic solution. We further analyze the orbital stability of the periodic orbits arising from bifurcation by applying Poore’s condition. Numerical simulation with some hypothetical sets of data has been done to support the analytical findings.