硫脲氧化的非线性动力学研究──H_2O_2－SC（NH_2）_2－Cu~（2＋）

研究了Ｈ_２Ｏ_２－ＳＣ（ＮＨ_２）_２－Ｃｕ~（２＋）－Ｈ~＋反应体系在封闭条件下以及在ＣＳＴＲ中的振荡行为。体系在封闭条件下出现单峰振荡行为，其振幅和诱导期与反应温度、［Ｈ_２Ｏ_２］、［ＳＣ（ＮＨ_２）_２］等有关，在ＣＳＴＲ中体系的Ｐｔ电极电位、铜离子选择性电极电位以及ｐＨ值均显示稳定的周期性振荡；考察其振荡过程的流速序列，发现在低流速下出现周期性复杂振荡，体系没有双稳态出现。     

碘酸盐-硫脲非缓冲体系的动力学行为与机理

研究了在非缓冲介质中碘酸盐氧化硫脲的复杂动力学行为, 结果发现在封闭条件下体系的pH, [I^−]及铂电极电位呈现单峰或准振荡现象. 当碘酸盐过量时, 体系的pH首先快速上升, 然后自催化下降, 最后上升趋向平缓, 体系碘钟产生的诱导期与体系初始pH成正比; 而当硫脲过量时, 体系的pH呈现单峰振荡行为并伴随着I₂瞬时产生与瞬时消耗的过程, [I₂]到达极值的诱导期与体系初始pH呈线性关系. 运用包含质子平衡反应、碘钟反应、碘-硫反应以及硫-硫反应的14步反应机理模拟出了封闭体系中pH, [I^−]以及[I₂]的单峰振荡或准振荡行为.     

小世界网络上的扩散限制的聚集-湮没反应动力学

通过Monte-Carlo模拟,研究了基于NW网络的两种类集团不可逆聚集-湮没过程的动力学行为.在系统中,两个同种类集团相遇,将不可逆地聚集成一个更大的集团;不同种类的两个集团相遇,则发生部分湮没反应.模拟结果表明,1)当捷径量化参数p相对较大或较小时,系统经较长时间演化后,集团密度c(t)和粒子密度g(t)呈现幂律形式,c(t)∝t^－α和g(t)∝t^－β,其中幂指数α和β满足α=2β的关系;2)当p为其他值时,集团密度和粒子密度随时间按非严格的幂 关键词： 聚集-湮没过程 小世界网络 反应动力学 Monte-Carlo模拟')" href="#">Monte-Carlo模拟     

Competing role of catalysis-coagulation and catalysis-fragmentation in kinetic aggregation behaviours

We propose a kinetic aggregation model where species A aggregates evolve by the catalysis-coagulation and the catalysis-fragmentation,while the catalyst aggregates of the same species B or C perform self-coagulation processes.By means of the generalized Smoluchowski rate equation based on the mean-field assumption,we study the kinetic behaviours of the system with the catalysis-coagulation rate kernel K(i,j;l) ∝ l ν and the catalysis-fragmentation rate kernel F(i,j;l) ∝ l μ,where l is the size of the catalyst aggregate,and ν and μ are two parameters reflecting the dependence of the catalysis reaction on the size of the catalyst aggregate.The relation between the values of parameters ν and μ reflects the competing roles between the two catalysis processes in the kinetic evolution of species A.It is found that the competing roles of the catalysis-coagulation and catalysis-fragmentation in the kinetic aggregation behaviours are not determined simply by the relation between the two parameters ν and μ,but also depend on the values of these two parameters.When ν μ and ν≥ 0,the kinetic evolution of species A is dominated by the catalysis-coagulation and its aggregate size distribution a k(t) obeys the conventional or generalized scaling law;when ν μ and ν≥ 0 or ν 0 but μ≥ 0,the catalysis-fragmentation process may play a dominating role and a k(t) approaches the scale-free form;and in other cases,a balance is established between the two competing processes at large times and a k(t) obeys a modified scaling law.     

Pd纳米粒子敏化的纳米单层TiO_2-Ru(Ⅱ)螯合物修饰电极对单磷酸鸟苷的电催化氧化行为

利用LB膜技术可控制备了纳米单层的二氧化钛-有机钌螯合物杂化膜,并研究了上述无机-有机杂化膜修饰电极在Pd纳米粒子敏化后对单磷酸鸟苷(GMP)的电催化氧化行为.实验结果表明:(1)纳米单层TiO2/[Ru(phen)2(dC18bpy)]2+(简称为TiO2-Ru)杂化膜的平均厚度为(3.2±0.5)nm;(2)在光照条件下TiO2-Ru杂化膜能有效催化还原[Pd(NH3)4]2+形成粒径位于20～200nm之间的Pd纳米粒子;(3)纳米单层TiO2-Ru/Pd杂化膜能高效催化氧化具有供电子能力的单磷酸鸟苷(GMP),与纳米单层TiO2-Ru杂化膜修饰的ITO电极(ITO/TiO2-Ru)相比,当工作电压为1200mV时,ITO/TiO2-Ru/Pd电极在含有1×10-3molL-1GMP的磷酸盐缓冲液中,单位面积的催化氧化电流提高了约36倍;(4)Pd纳米粒子的引入消除了金属钌螯合物中配体对电子传递的阻碍作用,改变了电子传递途径,从而有效减少了电子空穴对的复合,提高了杂化膜修饰电极(ITO/TiO2-Ru/Pd)的电子传递效率.     

Analytical results for the cluster size distribution in controlled deposition processes

This paper proposes a controlled particle deposition model for cluster growth on the substrate surface and then presents exact results for the cluster (island) size distribution. In the system, at every time step a fixed number of particles are injected into the system and immediately deposited onto the substrate surface. It investigates the cluster size distribution by employing the generalized rate equation approach. The results exhibit that the evolution behaviour of the system depends crucially on the details of the adsorption rate kernel. The cluster size distribution can take the Poisson distribution or the conventional scaling form in some cases, while it is of a quite complex form in other cases.     

中国人口分布规律及演化机理研究

近20年来,中国的总人口近似地按指数规律增加,但增加的速度有减缓的趋势.省、市、县三级的人口分布具有相似的规律：人口数k小的各级人口分布随k缓慢地变化;而k较大时,人口分布随k急剧变化,满足齐普夫定律.研究结果表明中国人口系统的各级分布具有自相似性.采用无标度网络上的聚集体迁移模型较好地解释了中国人口分布的演化规律. 关键词： 人口分布 齐普夫定律 迁移 动力学行为     

亚氯酸盐-硫代硫酸盐非缓冲体系的动力学

研究了亚氯酸盐-硫代硫酸盐反应体系在非缓冲条件下的复杂动力学行为.结果发现,在开放体系中反应的pH值和Pt电位存在准周期振荡分叉和混合模式振荡分叉通向混沌的过程，且pH峰与Pt电位峰反相位.当与起始浓度比相对较小时，随着流速的逐渐升高，体系的pH值和Pt电位从简单的小振幅振荡(S)经过准周期振荡分叉到混沌，最后回到简单大振幅振荡(L)；而当与起始浓度比相对较高时，随着流速的降低，体系的pH值和Pt电位出现LS1、LS2、LS3…LSn的混合模式振荡,并在每对(LSn、LSn＋1)振荡区间发现了LSn、LSn＋1随机出现的非周期振荡行为.运用硫价态变化的一般动力学模型，模拟出了反应体系的混合模式振荡及非周期振荡.     

KIO_3-KSCN-H~+反应体系的非线性动力学研究

研究了 KIO3-KSCN-H+反应体系在连续搅拌流动反应器 ( CSTR)中的非线性动力学行为 .在 CSTR中 ,该反应体系的 Pt电极电位显示出持续振荡现象 ,振荡的浓度范围非常宽 .通过酸度及各种金属离子对体系振荡行为影响的研究发现 ,对振荡体系具有催化作用的可能物种是 H+ 离子而不是金属离子     

Synthesis and crystal structure of polymer cobalt(II) complex, 1,2,4,5-benzenetetracarboxylate hexaimidazole tetraaqua cobalt (II) tetrahydrate

The crystal structure of the title complex {[Co(TCB)2/2-(IMI)2(H2O)2][Co(IMI)4(H2O)2] } (H2O)4 (where TCB = 1,2,4,5-benzenetetracarboxylic anion; IMI = imidazole) has been determined by X-ray diffraction method. Crystal data for {[Co(TCB)2/2(IMI)2(H2O)2][Co(IMI)4(H2O)2]}-(H2O)4: triclinic, space group P 1, a = 1.0647(2) nm, b = 1.1165(1)nm,c = 1.00361(1)nm,α = 91.56(1)°,β = 111.34(1)°, γ = 115.642(10)°, V = 0.9772(3) nm5, Z = 1. The polymer cobalt (II) complex has a novel three-dimension network structure. Co(1) atom and Co(2) atom both are coordinated in an octahedral arrangement and located in the center of the coordination anion and the center of the coordination cation, respectively. Moreover four carboxyl groups of TCB are divided into two types, two para-carboxyl groups bridge Co(1) atom in monodentate fashion and other two para-carboxyl groups are in free.