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11.
Transmission Properties of THz Radiation Pulses through Very Deep Zero-Order Metallic Gratings 下载免费PDF全文
Very deep zero-order metallic grating structures are processed to study the transmission properties of THz radiation pulses. The experiments have been performed with two samples. The delay of the THz pulses and the corresponding resonantly enhanced transmission spectra through the samples are observed. To explain the extraordinary transmission we have treated the samples as Fabry-Perot resonators through resonant excitation of the coupled surface plasmon polaritons filled in the cavities between the metal slats. The experimental results are in reasonable agreement with the numerical simulation. Our results show that THz-time-domain spectroscopy may be an effective technique for studying the optical properties of various THz microstructured devices. 相似文献
12.
Plastic deformation behaviour of Zr52.5Al10Ni10Cu15Be12.5 and Mg65Cu25Gd10 bulk metallic glasses (BMGs) is studied by using the depth-sensing nanoindentation and microindentation. The subsurface plastic deformation zone of the BMGs is investigated using the bonded interface technique. Both the BMGs exhibit the serrated flow depending on the loading rate in the loading process of indentation. Slow indentation rates promote more conspicuous serrations, and rapid indentations suppress the serrated flow. Mg-based BMG shows a much higher critical loading rate for the disappearance of the serration than that in Zr-based BMG. The significant difference in the shear band pattern in the subsurface plastic deformation zone is responsible for the different deformation behaviour between the two BMGs. Increase of the loading rate can lead to the increase of the density of shear bands. However, there is no distinct change in the character of shear bands at the loading rate of as high as1000 nm/s. 相似文献
13.
Unusual Transport Properties near the Insulator-Metal Transition in Colossal Magnetoresistive Manganites 总被引:2,自引:0,他引:2 下载免费PDF全文
It is argued that a combination of the Griffiths theory and the double-exchange mechanism predicts the random distribution of ferromagnetic metallic clusters above the Curie temperature TC in colossal magnetoresistive manganites. Along this line, we propose a model for the temperature dependence of resistivity that yields a quantitative agreement with experimental data obtained in a typical manganite La2/3Ca1/3MnO3. Our result indicates that the formation and growth of ferromagnetic metallic clusters are responsible for the observation of unusual transport properties near the insulator-metal transition. 相似文献
14.
分子聚集体在非线性光学和集成光学等领域有潜在的应用前景。纳米结构一维染料分子J—聚集体有许多既不同于单个分子又不同于体材料的奇异性质,即超辐射和巨光学非线性。这种超辐射是由于在几个本征态内振于强度结合在一起,得到一巨跃迁偶极于,因而是超辐射的。跃迁速率与耦合分子个数N成正比。分子聚集体的J—吸收和超辐射发射是共振的。利用Z—扫描技术测量PIC在不同配比下的非线性折射率、非线性吸收系数和非线性极化率。观测到随着链长变短,样品的三阶非线性极化率增大。对这种非线性增强的机制进行了分析和讨论。 相似文献
15.
Multiple—Scattering of Near—Edge x—ray Absorption Fine Structure of Sulphur—Passivated InP(100) Surface 下载免费PDF全文
We use the multiple-scattering cluster method to calculated the sulphur 1s near-edge x-ray absorption fine structure (NEXAFS) of S-passivated InP(100) surface.The physical origins of the resonances in the NEXAFS have been unveiled.It is shown that the most important resonance is attributed to the photoelectron scattering between the central sulphur and the nearest indium atoms.The studies show that two S-S dimers with the bond lengths of 2.05A and 3.05A coexist in the surface,meanwhile the bridge and antibridge site adsorption of single S could not be ruled out.We support the scanning tunnelling microscopy result that the S-passivated InP(100) surface exhibits significant discorder. 相似文献
16.
The dynamic behaviour of spiral tip in the light-sensitive Belousov-Zhabotinsky reaction under the influence of an externally applied light gradient was experimentally studied. The gradient causes different drifts for different spiral patterns. The centre of the spiral wave moved toward the region of lower light intensity. The direction of an additional perpendicular drift depended on the chirality of the spiral wave. The dependences of the drifting angle and the drifting velocity on light gradient have been measured. 相似文献
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FENGYi-Si YAORi-Sheng ZHANGLi-De 《中国物理快报》2004,21(7):1374-1376
SnO2/SiO2 nanocomposites have been prepared by the soaking-thermal-decomposing method, tin oxide nanoparticles are uniformly dispersed in the mesopores of silica. The optical absorption edge of the obtained nanocomposite presents a redshift compared with bulk tin oxide, With the increasing annealing temperature during the procedure of the sample preparation, the optical absorption edge of the sample moves to shorter wavelength (blueshift). These optical properties can be ascribed to the amorphous structure and band defects of surface layers of the tin oxide nanoparticles. 相似文献