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61.
Lv H Sun H Wang X Sun W Jiao G Zhou D Zhao L Cao H Zhang G 《Journal of separation science》2008,31(4):659-666
A simple, sensitive, and validated method was developed for simultaneous determination of scoparone, capillarisin, rhein, and emodin in rat urine by ultra-performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry (UPLC-MS). The urinary samples were analyzed on an Acquity UPLC BEH C18 1.7 microm 2.1x50 mm column. Scoparone, capillarisin, rhein, and emodin in rat urine were simultaneously analyzed with good separation. The lower limits of detection were 6.0, 9.0, 7.0, and 3.0 ng/mL, and the lower limits of quantification were 20.0, 33.0, 24.0, and 12.0 ng/mL for scoparone, capillarisin, rhein, and emodin, respectively. The intra- and inter-day precisions (RSD) were less than 9%. The intra- and inter-accuracies were found to be in the range of 94.14-104.54% for scoparone, 101.72-107.34% for capillarisin, 95.24-103.59% for rhein, and 101.32-107.82% for emodin at three concentration levels. The absolute recoveries for scoparone, capillarisin, rhein, and emodin were not less than 77.0%. The developed method has been applied to determine scoparone, capillarisin, rhein, and emodin in rat urine after oral administration of Yin Chen Hao Tang preparation, a traditional Chinese medicine formulation widely used in China for treatment of jaundice and liver disorders. 相似文献
62.
《Surface and interface analysis : SIA》2003,35(6):548-551
In this paper the bulk vacancy formation energies (Ev) of Al single crystals (with different surface orientations (111), (100) and (110)) were calculated with the embedded atom method using the empirical many‐body potential of Sutton and Chen. These calculations indicate that there is a significant difference in the bulk vacancy formation energy underneath different surface orientations. The crystal with the (111) surface had the highest bulk vacancy formation energy and the crystal with the (110) surface had the lowest bulk vacancy formation energy. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
63.
Miguel A. Javaloyes Victoria Miguel A. Meroñ o Bayo 《Transactions of the American Mathematical Society》2003,355(1):169-176
We study the total lifts of curves by means of a submersion that satisfy the condition analyzing, in particular, the cases in which the submersion has totally geodesic fibres or integrable horizontal distribution. We also consider in detail the case (biharmonic lifts). Moreover, we obtain a biharmonic lift in by means of a Riemannian submersion that has non-constant mean curvature, getting so a counterexample to the Chen conjecture for with a non-flat Riemannian metric.
64.
Parameters identification and adaptive full state hybrid projective synchronization of chaotic (hyper-chaotic) systems 总被引:1,自引:0,他引:1
Based on the active control idea and the invariance principle of differential equations, a general scheme of adaptive full state hybrid projective synchronization (FSHPS) and parameters identification of a class of chaotic (hyper-chaotic) systems with linearly dependent uncertain parameters is proposed in this Letter. With this effective scheme parameters identification and FSHPS of chaotic and hyper-chaotic systems can be realized simultaneously. Numerical simulations on the chaotic Chen system and the hyper-chaotic Chen system are presented to verify the effectiveness of the proposed scheme. 相似文献
65.
66.
Based on complex Chen and complex Lorenz systems, a novel color image encryption algorithm is proposed. The larger chaotic ranges and more complex behaviors of complex chaotic systems, which compared with real chaotic systems could additionally enhance the security and enlarge key space of color image encryption. The encryption algorithm is comprised of three step processes. In the permutation process, the pixels of plain image are scrambled via two-dimensional and one-dimensional permutation processes among RGB channels individually. In the diffusion process, the exclusive-or (XOR for short) operation is employed to conceal pixels information. Finally, the mixing RGB channels are used to achieve a multilevel encryption. The security analysis and experimental simulations demonstrate that the proposed algorithm is large enough to resist the brute-force attack and has excellent encryption performance. 相似文献
67.
We present the generalized forms of Parrondo's paradox existing in fractional-order nonlinear systems. The generalization is implemented by applying a parameter switching(PS) algorithm to the corresponding initial value problems associated with the fractional-order nonlinear systems. The PS algorithm switches a system parameter within a specific set of N ≥ 2 values when solving the system with some numerical integration method. It is proven that any attractor of the concerned system can be approximated numerically. By replacing the words "winning" and "loosing" in the classical Parrondo's paradox with "order" and "chaos", respectively, the PS algorithm leads to the generalized Parrondo's paradox:chaos_1+ chaos_2+ ··· + chaosN= order and order_1+ order_2+ ··· + orderN= chaos. Finally, the concept is well demonstrated with the results based on the fractional-order Chen system. 相似文献
68.
Based on the Chen chaotic system, a new four-dimensional hyperchaotic Chen system is constructed, and the basic dynamic behaviours of the system were studied, and the generalized synchronization has been observed in the coupled four-dimensional hyperchaotic Chen system with unknown parameters. The Routh--Hurwitz theorem is used to derive the conditions of stability of this system. Furthermore based on Lyapunov stability theory, the control laws and adaptive laws of parameters are obtained to make generalized synchronization of the coupled new four-dimensional hyperchaotic Chen systems. Numerical simulation results are presented to illustrate the effectiveness of this method. 相似文献
69.
《Physics letters. A》2020,384(10):126202
This paper avails of classical Lie symmetry analysis to exhibit optical solitons to Chen–Lee–Liu model. By the aid of the proposed method, we secure symmetries that transform the model to a system of ordinary differential equations which are subsequently investigated by a number of methods to recover bright, dark and singular solitons. 相似文献
70.
In this paper, the existence of multiple limit cycles for Chen system are investigated. By using the method of computing the singular point quantities, the simple and explicit parametric conditions can be determined to the number and stability of multiple limit cycles from Hopf bifurcation. Especially, at least 4 limit cycles can be obtained for the Chen system as a three-dimensional perturbed system. 相似文献