A novel adaptive fuzzy sliding-mode controller for uncertain chaotic systems

This paper is concerned with the stabilization problem for a class of uncertain chaotic systems. Based on a set of linguistic rules, a novel variable universe fuzzy sliding-mode control approach is designed to improve the robustness and the stability of system. Based on Lyapunov stability theory, the overall closed-loop system is shown to be stable. The designed controller not only can control the uncertain chaotic system to a desired state, but also the control action is smooth without chattering. Simulation examples are presented to further illustrate the advantage of the proposed method.     

主通道位置不固定的设施布局问题多目标优化模型及算法

以物流中心设施布局问题为对象,提出了考虑出入口及主通道位置不固定情况下的设施布局问题的多目标优化模型并设计了其改进的遗传算法。首先,以物料搬运成本最小、活动关系密切度最大和面积利用率最大为目标,构建了考虑出入口位置不固定条件下的具有I型主通道的设施布局多目标优化数学模型。然后,设计了一种改进的遗传算法,包括:改进的编码、解码方法,追加了解码修正操作,基于惩罚函数策略的适应度函数等。实例测试表明,本算法的执行效率高而且结果稳定,优化效果好,布局结果紧凑适用。     

光诱导高铁肌红蛋白还原的光谱法研究

采用紫外-可见吸收、荧光及圆二色(CD)等光谱法为主要分析手段, 对光诱导高铁肌红蛋白(metmyoglobin, metMb)还原及其引起的蛋白结构变化进行了研究. 采用氙灯430 nm的单色光和紫外灯对高铁肌红蛋白溶液进行光照实验, 实验结果显示, 在metMb的Q吸收带545 nm和580 nm附近吸收峰强度显著增强. 通过验证性实验, 证明光照后metMb发生了还原反应. 验证性实验包括: metMb中加入还原剂连二亚硫酸钠实验|光照后样品加入氧化剂铁氰化钾的可逆性实验|光照的同时通入CO实验. 进一步讨论表明, 采用氙灯430 nm的单色光诱导metMb还原的机理为光诱导的分子内电子转移. 此外, 对光还原反应后的样品进行同步荧光和CD光谱分析, 发现蛋白质色氨酸残基微环境极性增加, α-螺旋的含量由 63%下降到57%, 而β-折叠的含量增加了7%.     

截短胰高血糖素样肽-1的构象研究

截短胰高血糖素样肽-1(sGLP-1)不仅具备刺激胰岛β细胞增生和降低血糖的功能, 而且半衰期较长, 具有非常好的新药开发前景. 为了阐明sGLP-1的功能, 本文运用圆二色光谱和荧光光谱探究了sGLP-1在不同条件下的构象, 结果表明, sGLP-1在磷酸盐缓冲液中主要呈无规则构象, 螺旋含量很低; 在含十二烷基硫酸钠或三氟乙醇的磷酸盐缓冲液中主要呈螺旋构象. 溶液pH值和温度变化对sGLP-1的构象影响显著. sGLP-1保留了结合并激活受体的关键残基, 在受体的诱导下, 在体内形成正确构象, 从而结合并激活受体, 发挥它的功能. 研究结果表明, 适当缩短GLP-1 C端片段, 能获得作用时间长、效力高的GLP-1类似物.     

Projective synchronization of spatiotemporal chaos in a weighted complex network

<正>Projective synchronization of a weighted complex network is studied in which nodes are spatiotemporal chaos systems and all nodes are coupled not with the nonlinear terms of the system but through a weighted connection.The range of the linear coefficient matrix of separated configuration,when the synchronization is implemented,is determined according to Lyapunov stability theory.It is found that projective synchronization can be realized for unidirectional star-connection even if the coupling strength between the nodes is a given arbitrary weight value.The Gray-Scott models having spatiotemporal chaos behaviours are taken as nodes in the weighted complex network,and simulation results of spatiotemporal synchronization show the effectiveness of the method.     

毛细管电泳法高压快速分离分析菠菜中的水溶性维生素

在毛细管电泳法中,通过双模对接高压电源可以获得0～40 kV甚至40 kV以上的超高电压。本研究在40 kV的超高电压下,以纯电解质水溶液为缓冲液,实现了蔬菜中通常含有的8种水溶性维生素(VB1、VB2、VB6、VC、D-泛酸钙、D-生物素、烟酸和叶酸)的快速分离及菠菜样品的定量分析。通过考察电压、缓冲溶液浓度、pH值等因素对分离的影响,确定了优化的实验条件。结果表明,在40 kV高压下,采用25 mmol/L硼砂-硼酸溶液缓冲液(pH 8.8),菠菜中上述8种水溶性维生素在2.2 min内获得了较好的基线分离。用此方法对菠菜中的水溶性维生素进行定量分析,得到了令人满意的结果。水溶性维生素的线性相关系数范围为0.9981～0.9999,检出限为0.2～0.3 mg/L,在菠菜中的平均加标回收率为88.0%～100.6%,峰面积的相对标准偏差(RSD)为1.15%～4.13%。     

可见光谱法研究肌红蛋白血红素铁与金属离子相互作用(Ⅰ)

肌红蛋白(Myoglobin,Mb)是哺乳动物细胞主要是肌细胞贮存和分配氧的蛋白质, 由一条多肽链和一个血红素辅基构成,其血红素铁在氧气的传递和运输中起到关键作用。文章利用紫外-可见光谱法对肌红蛋白的血红素铁和外加金属离子M(Ⅱ)[Cu(Ⅱ), Zn(Ⅱ)和Co(Ⅱ)] 的直接相互作用进行了研究。结果发现, 金属离子M(Ⅱ)与肌红蛋白活性中心的Fe(Ⅱ)发生了直接相互作用,外加金属离子将铁离子从肌红蛋白中“拖拽”出来,形成部分空位肌红蛋白衍生物。同时研究了外界条件,如离子浓度对这种相互作用的影响,发现随着外加金属离子量的增加这种相互作用逐渐增强,其作用强度依次为Co(Ⅱ)＞Zn(Ⅱ)＞Cu(Ⅱ)。 研究证实了肌红蛋白的血红素铁与金属离子之间存在直接相互作用,并且离子浓度对这种相互作用有影响。     

Higher-Dimensional KdV Equations and Their Soliton Solutions

A (2+1)-dimensional KdV equation is obtained by use of Hirota method, which possesses N-soliton solution, specially its exact two-soliton solution is presented. By employing a proper algebraic transformation and the Riccati equation, a type of bell-shape soliton solutions are produced via regarding the variable in the Riccati equation as the independent variable. Finally, we extend the above (2+1)-dimensional KdV equation into (3+1)-dimensional equation, the two-soliton solutions are given.     

An efficient and stable structure preserving algorithm for computing the eigenvalues of a Hamiltonian matrix

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Coupled viscoplasticity damage constitutive model for concrete materials

A coupled viscoplasticity damage constitutive model for concrete materials is developed within the framework of irreversible thermodynamics.Simultaneously the Helmholtz free energy function and a non-associated flow potential function are given, which include the internal variables of kinematic hardening,isotropic hardening and dam- age.Results from the numerical simulation show that the model presented can describe the deformation properties of the concrete without the formal hypotheses of yield criterion and failure criteria,such as the volume dilatancy under the compression,strain-rate sen- sitivity,stiffness degradation and stress-softening behavior beyond the peak stress which are brought by damages and fractures.Moreover,we could benefit from the application of the finite element method based on this model under complex loading because of not having to choose different constitutive models based on the deformation level.