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Effective Medium Approximation for Nonlinear Composite Media 被引量:1
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作者 K.W.Yu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1993年第2期145-147,共3页
We build the perturbation expansion method for nonlinear composite media and extend the EMA for nonlinear effective conductivity. Using the solutions of boundary-value problems of a cylindrical in- clusion, we derive ... We build the perturbation expansion method for nonlinear composite media and extend the EMA for nonlinear effective conductivity. Using the solutions of boundary-value problems of a cylindrical in- clusion, we derive formulae for nonlinear effective conductivity. 展开更多
关键词 effective medium approximation COMPOSITE
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Effective Dielectric Response of Composites with Graded Material 被引量:1
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作者 YANGZi-Dong WEIEn-Bo SONGJin-Bao 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第6期957-960,共4页
The effective dielectric response of linear composites containing graded material is investigated under an applied electric field E_0.For the cylindrical inclusion with gradient dielectric function,ει(r)=b+cr,random... The effective dielectric response of linear composites containing graded material is investigated under an applied electric field E_0.For the cylindrical inclusion with gradient dielectric function,ει(r)=b+cr,randomly embedded in a host with dielectric constant εm,we have obtained the exact solution of local electric potential of the composite media regions,which obeys a linear constitutive relation D=εE,using hypergeometric function.In dilute limit,we have derived the effective dielectric response of the linear composite media.Furthermore,for larger volume fraction,the formulas of effective dielectric response of the graded composite media are given. 展开更多
关键词 effective dielectric response graded composite effective medium approximation
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Microwave backscattering from the sea surface with breaking waves 被引量:11
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作者 刘叶 魏恩泊 +1 位作者 洪洁莉 葛勇 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第9期2175-2179,共5页
Based on the effective medium approximation theory of composites, the whitecap-covered sea surface is treated as a medium layer of dense seawater droplets and air. Two electromagnetic scattering models of randomly rou... Based on the effective medium approximation theory of composites, the whitecap-covered sea surface is treated as a medium layer of dense seawater droplets and air. Two electromagnetic scattering models of randomly rough surface are applied to the investigation of microwave backscattering of breaking waves driven by strong wind. The shapes of seawater droplets are considered by calculating the effective dielectric constant of the whitecap layer. The responses of seawater droplets shapes, such as sphere and ellipsoid, to the backscattering coefficient are discussed. Numerical results of the models are in good agreement with the experimental measurements of horizontally and vertically polarized backscattering at microwave frequency 13.9GHz and different incidence angles. 展开更多
关键词 microwave backscattering effective medium approximation whitecaps wave breaking
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Fabrication and characterization of rugate structures composed of SiO_(2) and Nb_(2)O_(5) 被引量:2
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作者 R.Leitel O.Stenzel +3 位作者 S.Wilbrandt D.Gäbler V.Janicki N.Kaiser 《光学精密工程》 EI CAS CSCD 北大核心 2005年第4期505-511,共7页
Gradient index layers and rugate structures were fabricated on a Leybold Syrus pro deposition system by plasma-assisted coevaporation of the low index material silica and the high index material niobium pentoxide.To o... Gradient index layers and rugate structures were fabricated on a Leybold Syrus pro deposition system by plasma-assisted coevaporation of the low index material silica and the high index material niobium pentoxide.To obtain information about the compositional profiles of the produced layers,cross sectional transmission electron microscopy was used in assistance to deposition rate data recorded by two independent crystal monitors during the film preparation.The depth dependent concentration profiles were transformed to refractive index gradients by means of effective medium approximation.Based on the refractive index gradients the corresponding samples`transmission and reflection spectra could be calculated by utilizing matrix formalism.The relevance of the established refractive index profiles could be verified by comparison of the calculated spectra with the measured ones. 展开更多
关键词 physical vapor deposition effective medium approximation rugate structure
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Vapor Sensing Theoretical Study on Optical Microcavities
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作者 ZHANG Le-xin ZHANG Ran LI Zhi-quan 《Semiconductor Photonics and Technology》 CAS 2007年第3期200-205,共6页
When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. ... When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors. 展开更多
关键词 PSMs vapor sensing Bruggeman effective medium approximation theory capillary condensation transfer matrix numerical calculation
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