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951.
Guoping Dong Xiudi Xiao Xiaofeng Liu Bin Qian Yang Liao Chen Wang Danping Chen Jianrong Qiu 《Applied Surface Science》2009,255(17):7623-7626
Face-centered cubic Ag porous films have been prepared directly from the heat treatment of AgNO3-doped poly(vinyl alcohol) (PVA) electrospun nanofibers. Using Rhodamine B (RB) as the probing molecule, the surface-enhanced Raman scattering (SERS) effect of Ag porous films was demonstrated. The antibacterial activity of Ag porous films was also studied in this work. The propagation and biological activity of yeast cells were effectively inhibited by Ag porous films. These functional Ag porous films were expected to be applied in many fields, such as catalysis, diagnostics, sensors and antibacterial, etc. 相似文献
952.
In this paper the second harmonic generation (SHG) in generalized Thue-Morse (GTM(m, n)) ferroelectric superlattices is studied. Under the small-signal approximation, the SHG spectra in both real and reciprocal spaces are investigated. It is found that: (1) only when the structure parameters l, lA, and lB are all chosen to be proper, can SHG in GTM(m, n) ferroelectric superlattices be generated; (2) for Family A of generalized Thue-Morse, GTM(m, 1) ferroelectric systems, with the increase of parameter m, the intense peaks of SHG concentrate on the long wavelength (the fundamental beam (FB) wavelength is within ), but for Family B of generalized Thue-Morse, GTM(1, n) ferroelectric superlattices, with the increase of parameter n, the intense peaks of SHG concentrate on the middle wavelength ; and (3) for GTM(m, 1) ferroelectric superlattices, the bigger the m, the stronger the relative integral intensity (RII) of SHG would be, but for GTM(1, n) ferroelectric systems, the bigger the n, the weaker the RII of SHG would be. 相似文献
953.
954.
Using the random dyadic lattices developed by Hytönen and Kairema, we build up a bridge between BMO and dyadic BMO, and hence one between VMO and dyadic VMO, via expectations over dyadic lattices on spaces of homogeneous type, including both the one-parameter and product cases. We also obtain a similar relationship between Ap and dyadic Ap, as well as one between the reverse Hölder class RHp and dyadic RHp, via geometric–arithmetic expectations. These results extend the earlier theory along this line, developed by Garnett, Jones, Pipher, Ward, Xiao and Treil, to the more general setting of spaces of homogeneous type in the sense of Coifman and Weiss. 相似文献
955.
The problem of determining the steady-state axisymmetric temperature distribution in a bimaterial with a planar interface is considered here. The interface is either low or high conducting. Special Green’s functions satisfying the thermal conditions on the interface are derived and employed to obtain boundary integral equations whose path of integration does not include the interface. Boundary element procedures that do not require the interface to be discretized into elements are proposed for solving the problem under consideration. 相似文献
956.
The multi-scale analysis of fracture toughness of ferroelectric ceramics under complicate mechanical–electrical coupling effect is carried out in this paper. The generalized stress intensity factor (SIF) arising from spontaneous strains and polarization transformation in switching domain zones is accurately obtained by using an extended Eshelby theory. Taking BaTiO3 ferroelectric ceramic for example, it is discovered that the crack propagation can be induced by domain switching arising from negative electrical field when the crack surface is parallel to the isotropic plane, and the obtained critical electric displacement intensity factor (EDIF) approximates closely to that obtained by the Green’s function method. Additionally, as pinning dislocations and slip dislocations can strongly influence properties of ferroelectric devices and induce the property degradation, it is necessary to investigate the dislocation toughening effects on fatigue and fracture mechanisms. The results show that the dislocation shielding and anti-shielding effects on mode II SIF, mode I SIF and EDIF are obviously different when a dislocation locates at a position near the crack tip. Through the calculation of the critical applied EDIF for crack propagation by using mechanical energy release rate (MERR) theory, it is discovered that the slip angles obviously influence fracture toughness, and the mode II SIF arising from dislocation has little influence on fracture toughness, however, the mode I SIF and EDIF arising from dislocation have great influences on fracture toughness. 相似文献
957.
S. K. Liaw S. Wang C. S. Shin Y. L. Yu N. K. Chen K. C. Hsu A. Manshina Y. Tver’yanovich 《Laser Physics》2010,20(8):1744-1746
By using a subring cavity incorporated with a saturable absorber, a stable single-frequency selection is realized in a linear-cavity
fiber laser, which is constructed using a broadband fiber mirror and a partial reflectance fiber Bragg grating as the cavity
ends. At 1550.33 nm, the laser has an optical signal-to-noise-ratio of >53.28 dB and with linewidth less than 1 MHz. The pumping
efficiency is 25% improved by recycling the residual pump power to gain medium. The power stability and wavelength stability
have also been studied. 相似文献
958.
We develop an anisotropic perfectly matched layer (PML) method for solving the time harmonic electromagnetic scattering problems in which the PML coordinate stretching is performed only in one direction outside a cuboid domain. The PML parameters such as the thickness of the layer and the absorbing medium property are determined through sharp a posteriori error estimates. Combined with the adaptive finite element method, the proposed adaptive anisotropic PML method provides a complete numerical strategy to solve the scattering problem in the framework of FEM which produces automatically a coarse mesh size away from the fixed domain and thus makes the total computational costs insensitive to the choice of the thickness of the PML layer. Numerical experiments are included to illustrate the competitive behavior of the proposed adaptive method. 相似文献
959.
扩展的Sinh—Gordon方程展开法与Kaup—Kupershmidt方程的Jacobi椭圆函数解 总被引:1,自引:0,他引:1
利用扩展的Sinh—Gordon方程展开法研究了Kaup—Kupershmidt方程的Jacobi椭圆函数解,此方法也适用于求解其他非线性演化方程,从而丰富了方程解的范围. 相似文献
960.
Guanrong Chen 《Applicable analysis》2013,92(1-4):257-279
A general linear quadratic (LQ) optimal control problem, with the dynamic system being governed by a higher-order vector-valued ordinary differential equation and with inequality-constraints on the state vector and/or the control input, is studied. Based on an explicit characterization result, optimal solutions are obtained in closed-form. A constructive method for finding the closed-form optimal solutions is proposed, and two illustrative examples are included 相似文献