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51.
52.
Xiaoling Bao Jianhong Liu Qingshu Zheng Wei Pei Yimei Yang Yanyun Dai Tao Tu 《中国化学快报》1990,30(12):2266-2270
A novel protocol allowing convenient and highly selective visual recognition of melamine in raw milk via selective metallo-hydrogel formation at a concentration as low as 10 ppm without any tedious pretreatment has been developed. 相似文献
53.
A new class of proton exchange composite membranes made by incorporating phosphosilicate gels into SPPO matrix was prepared and characterized. The thermal stability was evaluated by TGA and DSC, and the amorphous structure information was provided from XRD. The experimental results showed that the composite membranes have good stability to oxidation by Fenton's reagent test, and the membrane dimension is hardly changed, even at high temperature. The hydration number values of the persulfonic acid group of composite membranes were lower than that of Nafion 112 at room temperature, but the water uptake of composite membranes at 80°C was higher than that of Nafion 112. With increasing relative humidity and doping amount, the conductivity of the composite membranes increased. Moreover, the conductivities of water-equilibrated composite membranes were higher than that of Nafion 112 (0.0871 S/cm) at room temperature, and the highest conductivity for the composite membrane was 0.216 S/cm. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
54.
This paper is concerned with the existence, smoothness and attractivity of invariant manifolds for evolutionary processes on general Banach spaces when the nonlinear perturbation has a small global Lipschitz constant and locally Ck-smooth near the trivial solution. Such a nonlinear perturbation arises in many applications through the usual cut-off procedure, but the requirement in the existing literature that the nonlinear perturbation is globally Ck-smooth and has a globally small Lipschitz constant is hardly met in those systems for which the phase space does not allow a smooth cut-off function. Our general results are illustrated by and applied to partial functional differential equations for which the phase space (where r>0 and being a Banach space) has no smooth inner product structure and for which the validity of variation-of-constants formula is still an interesting open problem. 相似文献
55.
Jianhong Shen Gilbert Strang 《Proceedings of the American Mathematical Society》1996,124(12):3819-3833
To study wavelets and filter banks of high order, we begin with the zeros of . This is the binomial series for , truncated after terms. Its zeros give the zeros of the Daubechies filter inside the unit circle, by . The filter has additional zeros at , and this construction makes it orthogonal and maximally flat. The dilation equation leads to orthogonal wavelets with vanishing moments. Symmetric biorthogonal wavelets (generally better in image compression) come similarly from a subset of the zeros of . We study the asymptotic behavior of these zeros. Matlab shows a remarkable plot for . The zeros approach a limiting curve in the complex plane, which is the circle . All zeros have , and the rightmost zeros approach (corresponding to ) with speed . The curve gives a very accurate approximation for finite . The wide dynamic range in the coefficients of makes the zeros difficult to compute for large . Rescaling by allows us to reach by standard codes.
56.
Desynchronization of large scale delayed neural networks 总被引:2,自引:0,他引:2
Yuming Chen Ying Sue Huang Jianhong Wu 《Proceedings of the American Mathematical Society》2000,128(8):2365-2371
We consider a ring of identical neurons with delayed nearest neighborhood inhibitory interaction. Under general conditions, such a network has a slowly oscillatory synchronous periodic solution which is completely characterized by a scalar delay differential equation with negative feedback. Despite the fact that the slowly oscillatory periodic solution of the scalar equation is stable, we show that the associated synchronous solution is unstable if the size of the network is large.
57.
58.
基于DSP实现的数字化闭环光纤陀螺 总被引:2,自引:0,他引:2
提出一种基于高速数字信号处理专用DSP芯片使用的数字化闭环光纤陀螺系统方案,并着重讨论其数字快速算法的实现。这种快速算法采用多抽样率数字信号系统中抽取的高效结构实现,能够在保证系统的实时性和精度的条件下,极大地减少了DSP系统的运算量和存储量。 相似文献
59.
We report the modification of various electrode surfaces with electropolymerized Magnus' green salts, [Pt(NH3)4 · PtCl4]
n
and [Pt(NH3)4 · PtCl6]
n
. The modified electrodes were prepared by cyclic scanning of the electrode potential in an aqueous solution containing Pt(NH3)4
2+ and PtCl4
2− or PtCl6
2− and the supporting electrolyte. The conditions for the film deposition were studied in detail. Several surface analytical
techniques, including micro-Raman scattering and X-ray diffraction, were employed to characterize the modifier film. The electrochemical
behavior of the modified electrode was studied in detail and the modified electrodes display very good electrocatalytic activity
in the oxidation of ascorbic acid, hydrogen peroxide, thiosulfate, and especially nitric oxide.
Received: 22 April 1999 / Accepted: 30 June 1999 相似文献
60.
Taishan Yi Yuming Chen Jianhong Wu 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2012,63(5):793-812
We consider a nonlocal delayed reaction–diffusion equation in an unbounded domain that includes some special cases arising from population dynamics. Due to the non-compactness of the spatial domain, the solution semiflow is not compact. We first show that, with respect to the compact open topology for the natural phase space, the solutions induce a compact and continuous semiflow ${\Phi}$ on a bounded and positively invariant set Y in C +?=?C([?1, 0], X +) that attracts every solution of the equation, where X + is the set of all bounded and uniformly continuous functions from ${\mathbb{R}}$ to [0, ∞). Then, to overcome the difficulty in describing the global dynamics, we establish a priori estimate for nontrivial solutions after describing the delicate asymptotic properties of the nonlocal delayed effect and the diffusion operator. The estimate enables us to show the permanence of the equation with respect to the compact open topology. With the help of the permanence, we can employ standard dynamical system theoretical arguments to establish the global attractivity of the nontrivial equilibrium. The main results are illustrated with the diffusive Nicholson’s blowfly equation and the diffusive Mackey–Glass equation. 相似文献