亚氯酸盐氧化硫脲非缓冲体系的复杂动力学行为

研究了ClO2--SC(NH2)2的非缓冲体系中的动力学行为,发现在开放体系中,体系的铂电极电位和pH呈现反相位连续的大幅度振荡,随着流速的降低,体系行为更加丰富,在高流速的混合模式之后出现了低流速的混合模式;在外部条件变化时,观察到了准周期振荡和倍周期振荡现象;考察了温度、流速、酸度以及反应物的初始浓度比等主要的影响因素,发现分叉参数的变化与体系的行为紧密相关。     

pH探针在亚氯酸盐-硫代硫酸钠非线性反应体系研究 中的应用

当pH探针应用于ClO2^--S2O3^2-非线性反应体系动力学研究时,发现了封闭体系的pH准振荡和CSTR中的pH稳态振荡现象,在CSTR中振荡的pH与铂电位同相位,且与闭系中小峰性质相同,反应机理包括氯氧化合物自身反应,氯氧化合物-硫化合物反应,硫-硫反应。以硫价态变化驱使的动力学模型模拟出闭系准振荡和CSTR中pH稳态振荡。该模型也为解释反应-扩散体系中的pH前沿波提供模型机理。     

高碘酸盐-亚硫酸盐反应体系的复杂动力学

研究了KIO4-Na2SO3-H2SO4 反应体系的复杂动力学，在酸性条件下（pH<3），发现碘电位、Pt电极电位和pH在封闭体系中显示单峰振荡以及半封闭体系和开放体系中的振荡现象.振荡现象受[Na2SO3]0/[KIO4]0比值以及体系的酸度影响.实验结果表明该体系可能为I2生成和I2消耗所驱动的振荡反应；所拟的反应机理解释了体系所显示的复杂动力学现象.     

硫脲氧化的非线性动力学研究——H2O2—SC（NH2）2—Cu^2＋反应体系

研究了Ｈ２Ｏ２－ＳＣ（ＮＨ２）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，（Ｈ２Ｏ２），（ＳＣ（ＮＨ２）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值均显著稳定的周期性振荡，考察期振荡过程的流速序列，发现在低流速下的出现周期性复杂振荡，体系没有双稳态出现。     

非缓冲介质中硫脲氧化的非线性动力学

研究了在非缓冲介质中高碘酸盐氧化硫脲的复杂反应动力学。实验结果表明：高碘酸盐氧化硫脲的非线性反应不但呈现多种不同的化学计量方程式,而且体系的pH、[I-]、[I2]及Pt电极电位呈现封闭条件下的准振荡和单峰振荡以及开放条件下的双稳态和衰减振荡行为。综合考虑硫价态与碘价态变化的各自非线性过程及相互耦合,提出了包含质子快速预平衡反应、碘化合物自身反应、碘化合物-硫化合物反应以及硫－硫反应的12步反应机理,模拟出了封闭体系中pH、[I-]以及[I2]的准振荡和单峰振荡以及开放体系中的双稳态行为。     

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。     

高碘酸盐-硫脲-硫酸反应体系的非线性动力学

研究了KIO4-SC(NH2)2-H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象;在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值犤KIO4犦0/犤SC(NH2)2犦0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象.     

高碘酸盐-硫脲-硫酸反应体系的非线性动力学

研究了KIO4 SC(NH2)2 H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象；在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值[KIO4]0/[SC(NH2)2]0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象.     

KBrO3-Na2SO3-K4Fe(CN)6体系pH振荡可控调节模拟研究

作为非线性化学的重要分支,pH振荡在生物学、物理学、医药学等众多领域中都发挥着重要的作用,需重点关注pH振荡反应机理及其数学模型的研究。本文通过实验验证化学计量网络分析(SNA)模型的准确性,并研究了KBrO₃-Na₂SO₃-K₄Fe(CN)₆反应体系(BSF反应)的动力学机理,结果表明流速越大,振荡反应振幅越小,周期越大。将遗传算法与传统的SNA模型进行结合,建立了pH振荡可控调节的方法,实现了BSF反应的周期与微幅值控制,指导应用中对振荡反应的可控调节。     

过氧化氢氧化硫化钠反应体系的复杂振荡

研究了过氧化氢和硫化钠反应体系在连续流动搅拌反应器中的复杂振荡行为. 观察到11型振荡、12型振荡、非周期振荡以及衰减振荡; 在振荡周期内, 拐点附近区域H+扰动产生的延迟与振荡相位pH有关. 在完全基于硫价态变化的经验速率方程模型的基础上进行数值模拟, 得到的各种复杂振荡行为与实验现象基本一致, 证明了硫价态变化可驱动复杂非线性动力学行为.     

丝氨酸-BrO^-~3-Mn^2^+-H2SO4体系振荡反应的研究

首次报道了间歇釜中以丝氨酸(Ser)-BrO^-~3-Mn^2^+-H2SO4为体系(简称Ser-BZ体系)的新型BZ类振荡反应,其特征如下：(1)虽然Ser不能发生溴代反应,但即使在无丙酮或惰性气体流时也能在间歇釜中观察到持续振荡;(2)振荡诱导期极短(～0),振荡次数较少(<11次);(3)振荡反应受到Cl^-,Br^-,丙烯腈等的抑制;但当加入足够量Ag^+使[Br^-]的振荡抑制后,仍可在Pt电极上观察到振荡现象。根据上述特征和反应产物分析,推测Ser-BZ振荡反应可能是自由基-控制模型,而非Br^--控制模型。加入适量丙酮可诱导连续振荡反应,归因于两种控制模型的共存。通过对Mn^3^+-Ser和BrO^-~3-Mn^2^+反应的动力学研究,并结合FKN机理,对Ser-BZ振荡反应机理进行了初步讨论。     

CSTR中H2O2-KSCN-CuSO4非线性反应体系的研究

非统性化学反应现象（包括化学振荡、化学波和化学混饨等）的研究近二十年来进展较快，BZ反应＊、NADH氧化的生化反应＊及卤类化合物主导的其它反应体系［’－’］的混饨、双节律等复杂非线性现象不断被发现并得到不同程度的确证．无卤无机反应体系的复杂非线性现象未见报导，我们选择H202－KSCN－CllS04－N。OH无卤体系K7］进行探索，此反应在连续搅拌反应器（CSTR）和封闭反应器（batch）皆有振荡现象，在体系中加入鲁米诺（11J．－－－－n由产生发光振荡现象问，我们对这个反应体系的进一步研究发现复杂振荡（包括非周期过程）…     

Time-slice velocity-map ion imaging studies of the photodissociation of NO in the vacuum ultraviolet region

The time-slice velocity-map ion imaging and the resonant four-wave mixing techniques are combined to study the photodissociation of NO in the vacuum ultraviolet (VUV) region around 13.5 eV above the ionization potential. The neutral atoms, i.e., N((2)D(o)), O((3)P(2)), O((3)P(1)), O((3)P(0)), and O((1)D(2)), are probed by exciting an autoionization line of O((1)D(2)) or N((2)D(o)), or an intermediate Rydberg state of O((3)P(0,1,2)). Old and new autoionization lines of O((1)D(2)) and N((2)D(o)) in this region have been measured and newer frequencies are given for them. The photodissociation channels producing N((2)D(o)) + O((3)P), N((2)D(o)) + O((1)D(2)), N((2)D(o)) + O((1)S(0)), and N((2)P(o)) + O((3)P) have all been identified. This is the first time that a single VUV photon has been used to study the photodissociation of NO in this energy region. Our measurements of the angular distributions show that the recoil anisotropy parameters (β) for all the dissociation channels except for the N((2)D(o)) + O((1)S(0)) channel are minus at each of the wavelengths used in the present study. Thus direct excitation of NO by a single VUV photon in this energy region leads to excitation of states with Σ or Δ symmetry (ΔΩ = ±1), explaining the observed perpendicular transition.     

A rate law model for the explanation of complex pH oscillations in the thiourea-iodate-sulfite flow system

In a continuous flow stirred tank reactor (CSTR), the reaction of thiourea-iodate-sulfite (TuIS) exhibits a rich variety of complex oscillations in pH. The transitions from 1(n) type oscillations to 1(3), 1(2) type and simple oscillations were observed on decreasing the flow rate gradually in small steps at 30.2 °C and 20.5 °C, respectively. The transitions from 1(n) type oscillations to 1(0)1(4), 1(0)1(3) type and simple oscillations were observed as well on increasing the temperature in small steps at a given flow rate. Based on the analogous iodate-sulfite-thiosulfate system a simple empirical rate law model is suggested to give a sound agreement between the experimental and simulated results on the complex oscillatory behaviour. A possible explanation of the emergence of the simple empirical rate law model from the mechanism of the individual reactions of the TuIS system is also discussed.     

Radical-controlled Oscillations in BrO3^——fructose-Mn^2＋-H2SO4 System

Sustained oscillations were observed in the BrO3^--fructose-Mn^2 -H2SO4 system. Unlike the classical BZ oscillations, the present oscillations might be considered as radicalcontrolled rather than bromide-controlled since no substance subjected to bromination was present. Addition of acetone induced dual-frequency oscillations comprised of both the radical-controlled and the bromide-controlled oscillations.     

Bioscillation and Birhythmicity in the H_2O_2-KSCN-CuSO_4-NaOH System

Two kinds of different mechanistic oscillations can be displayed in the H_2O_2-KSCN-CuSO_4-NaOH system. One discovered by this study is the pH oscillation in a continuous flow stirred tank reactor(CSTR) resulting from the oxidation of KSCN. The other is the oscillation of H_2O_2 decomposition in both CSTR and batch reactors(reported by Orbáin in 1986). Under appropriate experimental conditions, the system exhibits a birhythmicity in a CSTR. Two different pH oscillations are reported here. The pH oscillations which accompany the decomposition of H_2O_2 exist in the batch reactor and the CSTR at a high flowrate, but the pH oscillations in a CSTR at a low flowrate originates from proton positive and negative feedback in the oxidation of KSCN. The oscillation of non-catalyzed oxidation of KSCN by hydrogen peroxide in a CSTR can be found. Also we have observed whether Cu~(2+) exists or not in the batch system, the pH increases to near neutral ultimately after pH drops twice.     

一种新型亚胺基吡啶铁配合物和茂金属复配催化乙烯原位共聚制备LLDPE

20世纪80年代中期,Kissin等人^[1]首先采用了乙烯二聚催化剂和传统Ziegler-Natta催化剂组成双功能催化体系,催化乙烯原位聚合制备短支链线性低密度聚乙烯(LLDPE)．由于该方法具有不需要另外加入α-烯烃的特点,近年来受到人们的重视．胡友良^[2-4]等人用乙烯二聚催化剂Ti-     

Complex and chaotic oscillations in a model for the catalytic hydrogen peroxide decomposition under open reactor conditions

Numerous periodic and aperiodic dynamic states obtained in a model for hydrogen peroxide decomposition in the presence of iodate and hydrogen ions (the Bray-Liebhafsky reaction) realized in an open reactor (CSTR), where the flow rate was the control parameter, have been investigated numerically. Between two Hopf bifurcation points, different simple and complex oscillations and different routes to chaos were observed. In the region of the mixed-mode evolution of the system, the transitions between two successive mixed-mode simple states are realized by period-doubling of the initial state leading to a chaotic window in which the next dynamic state emerges mixed with the initial one. It appears in increasing proportions in concatenated patterns until total domination. Thus, with increasing flow rate the period-doubling route to chaos was obtained, whereas with decreasing flow rate the peak-adding route to chaos was obtained. Moreover, in very narrow regions of flow rates, chaotic mixtures of mixed-mode patterns were observed. This evolution of patterns repeats until the end of the mixed-mode region at high flow rates that corresponds to chaotic mixtures of one large and many small amplitude oscillations. Starting from the reverse Hopf bifurcation point and decreasing the flow rate, simple small amplitude sinusoidal oscillations were encountered and then the period-doubling route to chaos. With a further decreasing flow rate, the mixed-mode oscillations emerge inside the chaotic window.     

Cu~(2+)-Catalyzed Oscillatory Oxidation of Ascorbic Acid by O_2 Flow

The most widely studied oscillatory chemical reactions are based on homogeneous systems, such as the BrO3--driven BZ type oscillations1, the IO3--driven BR type oscillations2, and the ClO2- driven oscillations performed in CSTR3. Recently, oscillations have also been found in some heterogeneous systems, such as the oscillations across the liquid membrane4, the oscillations on the electrode5, and the oscillations in catalysis6. The metal-catalyzed oscillatory oxidation of the organic subst…     

Oscillatory character of deactivation of zeolite catalysts in carbonium ion conversions of hydrocarbons

We have observed damped oscillations of increasing frequency in alkylation of benzene by 1-decene, which we interpret based on surface competition between the benzene and the coke being formed according to a mechanism of alternating inversions of the adsorption layer. We propose a scheme for the inversions in terms of chemical potentials of the adsorbed components. The change in the character of the oscillations is connected with a qualitative change in the coke over time.__________Translated from Teoreticheskaya i Éksperimentalnaya Khimiya, Vol. 41, No. 1, pp. 40–44, January–February, 2005.