CONTROLLABILITY OF A CLASS OF HYBRID DYNAMIC SYSTEMS (Ⅱ)—SINGLE TIME_DELAY CASE

IntroductionConsideraswitchedlinearsystemwithsingletime_delayinthecontrolfunctiongivenby x(t) =Ar(t) x(t) +Br(t) u(t) +Dr(t) u(t -τ) ,(1)wherex(t) ∈Rnisthestate,u(t) ∈R mtheinput,thepiecewiseconstantscalarfunctionr(t) :R+ → 1,2 ,… ,Nistheswitchingpath ,(Ai,Bi,Di) ｜i =1,… ,Nisafinitefamilyofsystemrealizations.Moreover,r(t) =iimpliesthat(Ai,Bi,Di)ischosenasthesystemrealizationattimet.τ >0isthefixedtimedelayincontrol.Inthispaper ,wewillstudythecontrollabilityofsystem (1) .Theone_per…     

OBSERVATIONS OF HOMOCLINIC CHAOS THROUGH ALTERNATING PERIODIC-CHAOTIC SEQUENCES IN A NONLINEAR CIRCUIT

Homoclinic chaos in the alternating periodic-chaotic sequences is observed in a nonlinear circuit with sinusoidal driving force. In particular, a complete Alternating Periodic-Chaotic sequence is recorded with a high-resolution up to P⁽⁸⁾ state. The experimental results, analyzed by constructing the time of flight and the next maximal amplitude return maps, are in good agreement with the scenario described by Shilnikov. The underlying dynamics of homoclinic chaos is determined from the next amplitude return map, to be that of a unimodal map and thus a strong dissipation case.     

一类混杂动态系统的能控性(Ⅰ)——基本结果

首次将时滞现象引入到线性切换系统的模型中,研究含有时滞线性切换系统的能控性及其判定条件。全部工作由三部分组成,第Ⅰ部分首先,提出含时滞的线性切换系统的数学模型,并介绍切换系统的基本概念—切换序列。其次,引入列空间、循环不变子空间和广义循环不变子空间等基本几何概念,给出一些有关概念的基本性质,特别是分离引理。然后以一个基本引理的形式揭式某一积分方程的解集与广义循环不变子空间之间的联系,这个引理将在能控性的判定中起关键作用。这些概念和引理都将作为以后展开能控性分析所必需的研究工具。     

Morphological study of the localized growth of materials in dielectric barrier discharge

The localized growth of materials has been realized in a dielectric barrier discharge reactor in the mixture of acetylene and argon in previous work. In this paper, the morphology of the materials synthesized in the process is studied. The results indicate that the polymer's structure consists of three layers. The layer near the substrate is homogeneous with thickness of several micrometres; the middle layer is composed of dense bulges with height of about more than 10μm in average. The distance between two neighbouring bulges is about 230μm; the top layer is made up of a few large columns with the height up to 2mm, and with the average distance of about 3.5mm. The growth of the three layers corresponds to three types of discharge. The discharge mechanism is analysed through studying the morphology of the polymer. It can be deduced from the morphology that the first and second discharge phases should belong to the Townsend breakdown, and the last discharge phase should be explained on the basis of the streamer mechanism.     

Optical diagnostics of femtosecond laser plasmas

Optical diagnostics of evolution of plasmas produced by ultrashort laser pulses is carried out using a femtosecond probing beam. The time sequence of plasma shadowgrams and interferograms are obtained. The filamentation instability in high-density region induces the local density modification. Large-scale toroidal magnetic fields confine plasma expansion in the transverse direction, resulting in the formation of a plasma jet. The plasma expansion along the target normal direction is found to scale as t^1/2.     

纤维素磁性微球在病原微生物检测中的应用研究

采用反向悬浮包埋技术和高速匀浆法制备了不同粒径的纤维素磁性微球,扫描电镜和铁离子分析结果表明,最佳粒径为5.82μm。后采用自行构建并表达的融合蛋白CBD-ProA和沙门氏菌多价抗体对最佳粒径的纤维素磁性微球进行活化,获得免疫磁性微球,其抗体偶联量为186.8mg/mL。最后采用致敏的免疫磁性微球分别对污染沙门氏菌的饮用水、牛奶和花生酱等样品进行免疫磁性捕获及分子鉴定,其检测限均可达10cfu/100mL。本研究开发的免疫磁性捕获技术,具有微球活化速度快、工艺简单、使用便捷等优势,同时,建立的免疫磁性捕获-PCR的方法与国标法相比,检测时间缩短48h,在食品安全、环境检测等方面具有实用价值。     

西柏三烯-4,6-二醇衍生物的合成及抗肿瘤活性

以烟草中含量丰富的大环二萜类化合物2,7,11-西柏三烯-4,6-二醇(CBT)为母体, 其C6位羟基经酯化/醚化, 合成了28个西柏三烯-4-醇-6-羧酸酯及西柏三烯-4-醇-6-烷氧类化合物. 采用核磁共振波谱(NMR)和高分辨质谱(HRMS)对目标化合物进行了结构表征, 并初步评价了其生物活性. 细胞毒活性测试结果表明, 部分化合物对肿瘤细胞的抑制作用与阳性对照顺铂相当, 其中α-2,7,11-西柏三烯-4-醇-6-O-苯乙酸酯(1i)对乳腺癌细胞株MCF-7的IC₅₀值为15.45 μmol/L, α-2,7,11-西柏三烯-4-醇-6-O-(2-氟)苯乙酸酯(1t)对肺癌细胞株SMMC-7721的IC₅₀值为11.44 μmol/L.     

共轭效应

1.共轭体系的意义与类型(一)共轭体系的意义:由π键或 p 电子经过一个σ键与π键相连接而组成的体系,都叫共轭体系。最近有很多实验事实证明键的共轭效应现象不仅发生于重键之间(π,π共轭效应),而且也发生于单键和重     

等离子体中的颗粒成长模型

研究等离子体环境下的带电微小颗粒的成长过程．在收集离子和颗粒间凝合两种成长机制中,后者起主要作用,使生成的颗粒粒度接近．基于能量均分定理提出一个简化的模型,推导出颗粒粒度分布函数的动力方程．初步的数值模拟结果证实了上述成长机制的设想. 关键词：