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91.
92.
Synchronization of energy resource systems with mismatched parameters is investigated. An adaptive linear feedback control scheme for the synchronization of energy resource systems is proposed when the parameters of the master system are unknown and different from those of the slave system. Based on the Lyapunov stability theory, an adaptive control law is derived to make the states of two slightly mismatched chaotic systems asymptotically synchronized. Finally, numerical simulations are performed to verify the proposed results. 相似文献
93.
Stability analysis of highly nonlinear hybrid multiple-delay stochastic differential equations 下载免费PDF全文
Chen Fei Weiyin Fei Xuerong Mao Mingxuan Shen Litan Yan 《Journal of Applied Analysis & Computation》2019,9(3):1053-1070
Stability criteria for stochastic differential delay equations (SDDEs) have been studied intensively for the past few decades. However, most of these criteria can only be applied to delay equations where their coefficients are either linear or nonlinear but bounded by linear functions. Recently, the stability of highly nonlinear hybrid stochastic differential equations with a single delay is investigated in [Fei, Hu, Mao and Shen, Automatica, 2017], whose work, in this paper, is extended to highly nonlinear hybrid stochastic differential equations with variable multiple delays. In other words, this paper establishes the stability criteria of highly nonlinear hybrid variable multiple-delay stochastic differential equations. We also discuss an example to illustrate our results. 相似文献
94.
Stochastic delay Lotka-Volterra model 总被引:1,自引:0,他引:1
We reveal in this paper that the environmental noise will not only suppress a potential population explosion in the stochastic delay Lotka-Volterra model but will also make the solutions to be stochastically ultimately bounded. To reveal these interesting facts, we stochastically perturb the delay Lotka-Volterra model into the Itô form , and show that although the solution to the original delay equation may explode to infinity in a finite time, with probability one that of the associated stochastic delay equation does not. We also show that the solution of the stochastic equation will be stochastically ultimately bounded without any additional condition on the matrix A. 相似文献
95.
Xiaohua Jiang Yueyuan Chen Xuerong Yang Xiaojie Yan Fenglai Lu Zhangbin Liu Dianpeng Li 《Journal of separation science》2022,45(9):1570-1579
The root of Salvia bowleyana Dunn (Lamiaceae) is used as a traditional Chinese medicine that has multiple therapeutic effects. In this study, an efficient strategy was developed to separate diterpenoid compounds, which are the main active ingredients in Salvia bowleyana Dunn roots, from complex crude extracts by high-speed countercurrent chromatography combined with preparative high-performance liquid chromatography. A two-phase solvent system comprising n-hexane–ethyl acetate–methanol–water (7:3:7:3, v/v/v/v) was selected for high-speed countercurrent chromatographic separation. Three major diterpenoids, 6α-hydroxysugiol ( 7 ), sugiol ( 8 ), and 6, 12-dihydroxyabieta-5,8,11,13-tetraen-7-one ( 9 ) were obtained at purities of 98.9, 95.4, and 96.2%, respectively, and minor diterpenoids were enriched via one-step separation. The enriched minor diterpenoids were further purified by continuous preparative high-performance liquid chromatography to yield two new norabietanoids ( 1 , 6 ) and four known compounds ( 2 – 5 ). The structures of these new compounds were determined using NMR spectroscopy, high-resolution electrospray ionization mass spectrometry, and electronic circular dichroism spectroscopy. The results suggest that high-speed countercurrent chromatography combined with preparative high-performance liquid chromatography efficiently isolates diterpenoids, including minor components, from complex natural products. 相似文献
96.
Underwater acoustic target recognition is very complex due to the lack of labeled data sets, the complexity of the marine environment, and the interference of background noise. In order to enhance it, we propose an attention-based residual network recognition method (AResnet). The method can be used to identify ship-radiated noise in different environments. Firstly, a residual network is used to extract the deep abstract features of three-dimensional fusion features, and then a channel attention module is used to enhance different channels. Finally, the features are classified by the joint supervision of cross-entropy and central loss functions. At the same time, for the recognition of ship-radiated noise in other environments, we use the pre-training network AResnet to extract the deep acoustic features and apply the network structure to underwater acoustic target recognition after fine-tuning. The two sets of ship radiation noise datasets are verified, the DeepShip dataset is trained and verified, and the average recognition accuracy is 99%. Then, the trained AResnet structure is fine-tuned and applied to the ShipsEar dataset. The average recognition accuracy is 98%, which is better than the comparison method. 相似文献
97.
Yongmei Cai Xuerong Mao 《Stochastics An International Journal of Probability and Stochastic Processes》2020,92(2):193-222
ABSTRACTThis paper focuses on a predator-prey system with foraging arena scheme incorporating stochastic noises. This SDE model is generated from a deterministic framework by the stochastic parameter perturbation. We then study how the correlations of the environmental noises affect the long-time behaviours of the SDE model. Later on the existence of a stationary distribution is pointed out under certain parametric restrictions. Numerical simulations are carried out to substantiate the analytical results. 相似文献
98.
Surface modification of cotton fabrics by transesterification with ion-paired subtilisin Carlsberg in solvents 总被引:1,自引:0,他引:1
The transesterification-active enzyme subtilisin Carlsberg was successfully solubilized into organic solvents such as isooctane
by enzyme–bis(2-ethylhexyl) sulfosuccinate (AOT) ion-pairing while retaining its natural secondary structure and catalytic
activity. The optimal CaCl2 concentration and pH for enzyme extraction were 2 mM and 5.0, respectively, while the optimal pH for transesterification
capability of enzyme was around 7.5. Within the critical micellar concentration (CMC) of AOT in isooctane, increasing the
initial AOT concentration enhanced the extraction efficiency. As the hydrophobicity of the solvent decreased, so did the catalytic
efficiency of the enzyme, while transesterification of cotton fabrics (medical gauze and knitted cotton cloth) occurred only
in less hydrophobic solvents such as toluene. Transesterification was verified by infrared spectral analysis. The final degree
of substitution (DS, the number of propionate groups per cellulose monosaccharide unit) of the medical gauze and knitted cotton
cloth was 0.00282 and 0.00228, respectively. The surface properties of the modified cotton fabrics were characterized using
X-ray diffraction, scanning electron microscopy, thermogravimetry, water contact angle, etc. 相似文献
99.
Zhijia Zhang Yuxuan Hou Shaofei Zhang Guoliang Zhang Ming Li Huanming Lu Yong Li Xuerong Zheng Zhijun Qiao Zhenyang Yu Qin Huang Jianli Kang 《中国化学快报》2018,29(11):1656-1660
A novel Cu-SnO2 anode material derived from Cu6Sn5 alloy, retaining high conductivity of Cu and high theoretical capacity of SnO2 with a facile synthesizing process by oxidation and reduction method. The novel Cu structure penetrates in the composite particles inducing high conductivity and spaceconfined SnO2, which restrict the pulverization of SnO2 during lithiation/delithiation process. 相似文献
100.
A species having three sequential redox states is able to react with its higher oxidation (or lower reduction) state producing two equivalents of its middle redox state. A possible electrochemical signature of that comproportionation reaction is that the faradaic current from the two-electron process (I1,1) might not be twice the current of the corresponding one-electron process (I1,2). In this paper, using redox-active species with well-separated one- and two-electron processes, such as N,N′-di-n-heptylviologen, N-methyl-4-benzoylpyridinium perchlorate, TCNQ, TTF, N,N′-dimethylphenazine and TMPD, it is reported that within a wide range of the experimental parameters, two seemingly different electrochemical methods, namely sampled current voltammetry (SCV), a diffusion-controlled method, and rotating disk electrode (RDE) voltammetry, a convection-dominated method, give equal mass-transfer limited current ratios (I1,2/I1,1). These phenomena have been traced to the fact that close to the electrode distance-normalized concentration profiles generated from both SCV and RDE voltammetry are superimposable. Digital simulations have confirmed these conclusions, and have led to the elucidation of the relative roles of the comproportionation reaction rate constant, kf, and the diffusion-layer thickness, δ, in determining the value of the (I1,2/I1.1)SCV or RDE ratio: when the diffusion-layer is thicker, the comproportionation reaction time is longer and limiting (I1,2/I1,1) ratios are reached with lower kf values. (The larger δ corresponds to longer sampling times in SCV and slower electrode rotation rates in RDE voltammetry.). Ultimately, the limiting values of the (I1,2/I1,1)SCV or RDE ratios are controlled by the relative values of the diffusion coefficients of all three species involved in the comproportionation reaction. According to our results, the (I1,2/I1,1)SCV or RDE ratio can afford kinetic information on the comproportionation reaction, and comprises a diagnostic criterion for the relative diffusion coefficients of a redox-active species and its one-electron oxidized (or reduced) form. 相似文献