分数阶共轭Chen混沌系统中的混沌及其电路实验仿真

研究了分数阶共轭Chen混沌系统的混沌行为, 给出了分数阶共轭Chen系统存在混沌吸引子的必要条件. 并设计了一种传递函数的新电路单元用来实现分数阶共轭Chen混沌系统, 利用Multisim2001电子工作平台进行了电路实验仿真. 数值模拟和电路实验仿真结果相符, 证实了分数阶共轭Chen系统确实存在混沌现象和所设计电路单元的有效性. 关键词： 分数阶 共轭Chen混沌系统 电路单元 电路仿真     

The Chen-Ruan cohomology of almost contact orbifolds

Comparing to the Ch-~Ruan cohomology theory for the almost complex orbifolds, we study the orbifold cohomology theory for almost contact orbifolds. We define the Chen-Ruan cohomology group of any almost contact orbifold. Using the methods for almost complex orbifolds, we define the obstruction bundle for any 3-multisector of the almost contact orbifolds and the Chen~Ruan cup product for the Che-Ruan cohomology. We also prove that under this cup product the direct sum of all dimensional orbifold cohomology groups constitutes a cohomological ring. Finally we calculate two examples.     

Theoretical and experimental study of Chen chaotic system with notch filter feedback control

Since the past two decades, the time delay feedback control method has attracted more and more attention in chaos control studies because of its simplicity and efficiency compared with other chaos control schemes. Recently, it has been proposed to suppress low-dimensional chaos with the notch filter feedback control method, which can be implemented in a laser system. In this work, we have analytically determined the controllable conditions for notch filter feedback controlling of Chen chaotic system in terms of the Hopf bifurcation theory. The conditions for notch filter feedback controlled Chen chaoitc system having a stable limit cycle solution are given. Meanwhile, we also analysed the Hopf bifurcation direction, which is very important for parameter settings in notch filter feedback control applications. Finally, we apply the notch filter feedback control methods to the electronic circuit experiments and numerical simulations based on the theoretical analysis. The controlling results of notch filter feedback control method well prove the feasibility and reliability of the theoretical analysis.     

Modified Projective Synchronization of a New Hyperchaotic System via Nonlinear Control

In this paper, a nonlinear control scheme of two identical hyperchaotic Chensystems is developed to realize their modified projective synchronization.We achieve modified projective synchronization between the two identicalhyperchaotic systems by directing the scaling factor onto the desired value. With symbolic computation system Maple and Lyapunov stability theory, numerical simulations are given to perform the process of the synchronization.     

Assessment of heavy metals,fungicide quintozene and its hazardous impurity residues in medical Panax notoginseng (Burk) F.H.Chen root

A quick, easy, cheap, effective, rugged, and safe extraction approach and gas chromatography/tandem mass spectrometry with programmed temperature vaporization sampling technology were used to determine fungicide quintozene and its hazardous impurity hexachlorobenzene (HCB) in Panax notoginseng root, which is commonly used as a rare traditional Chinese medicine worldwide. The mean recoveries were in the ranges of 94–125 and 84–119% for quintozene and HCB with relative standard deviations of 6.2–16.1% at three concentrations: 0.01, 0.1 and 1 mg kg^?1. Heavy metals arsenic, cadmium, copper and lead were simultaneously detected by an inductively coupled plasma–mass spectrometry approach after digestion with nitric acid. The above methods were used to analyze 50 samples of P. notoginseng roots collected at markets and planting bases from the special local producing areas, namely, Honghe, Kunming and Wenshan in Yunnan province, China. Quintozene and HCB in root samples were determined at <0.0015–1.50 and <0.0015–0.125 mg kg^?1. In the 50 samples, 28, 16, 56, 6 and 2% exceeded the maximum permissible levels in medicinal plants (WM/T2‐2004) for quintozene, arsenic, cadmium, lead and copper. [Correction added on 28 January 2019, after first online publication: the percentages in the preceding sentence have been corrected]. The results showed that the method is robust and suitable for measuring quintozene, its hazardous impurity and heavy metals in P. notoginseng roots.     

A comparative study on volatile metabolites profile of Dracaena cochinchinensis (Lour.) S.C. Chen xylem with and without resin using GC‐MS

Dragon's blood is a famous traditional Chinese medicine produced from source plants under bio‐ or abio‐stress. Dracaena cochinchinensis (Lour.) S.C. Chen xylem (DX) is one of the most important sources of the medicine. In this work, a GC‐MS method was developed for analysis of the n‐hexane extracts of DX with resin (DXR) and without resin (DXW). The repeatability of the method was also investigated for a metabolite comparative study of the different xylems. About 80 components were detected, 26 of which were identified in both DXR and DXN. Three sesquiterpenes (τ‐cadinol, τ‐muurolon and α‐cadinol) were first discovered in Dracaena cochinchinensis (Lour.) S.C. Chen. The chromatographs of the two plant materials were compared and differences of compounds were found. It showed that phytosterols showed a dramatic rise in content, and sesquiterpenes were found to be synthesized in DXR. Copyright © 2015 John Wiley & Sons, Ltd.     

三七花化学成分和药理作用的研究进展

三七花含有丰富的人参二醇型皂苷、黄酮和多糖等生物活性成分.现就三七花的化学成分和药理作用研究进展进行简要概述,为其研究与开发提供有价值的参考.     

Bifurcation analysis and feedback control of a 3D chaotic system

In this paper, we analyze a three-dimensional differential system derived from the Chen system based on the first Lyapunov coefficient, and apply it to investigate the local bifurcation. And we present some insights on bifurcation and stability, also obtain some conditions for subcritical and supercritical. Finally, we give some numerical simulation studies of system in order to verify analytic results.     

非线性互补问题的一种不可行非内点连续方法

基于 Chen- Mangasarian光滑函数的一个子类 ,针对单调非线性互补问题给出了一种不可行非内点连续方法预估校正算法 ,并在适当的条件下 ,证明了算法具有全局线性收敛性和局部二次收敛性。     

On upper bounds for the variance of functions of random variables

The upper bounds for the variance of a function g of a random variable X obtained in Cacoullos (1982) (for short CP) are improved in the case μ = E(X) ≠ 0. A main feature of these bounds is that they involve the second moment of the derivative or the difference of g. A multivariate extension for functions of independent random variables is also given.