253 research outputs found
Influence of near-field electromagnetic interactions on optical properties of perfect lens consisting of left-handed material
No full textIn this paper, we investigate the surface plasma resonance of a slab of left-handed material (LHM).We use the transfer matrix method to calculate the attenuated total reflection spectra of the LHM slab. The intrinsic parameters of the LHM slab are suitable chose so that the slab has both negative permittivity & permeability in a frequency range of visible light. We have calculated the cases with different slab thickness & various dielectrics surrounding the LHM slab
Plasmonic effects of metal and negative refraction slab
No full text在這篇論文中，我們將概略介紹光與物質交互作用之基本電磁理論、平板結構的表面電漿共振理論以及負折射物質之基本性質，並以傳輸矩陣的方法，計算鋁金屬與負折射物質平板系統的ATR光譜以及電場強度的空間分佈。從計算的結果中可以看出，不論是鋁金屬或負折射物質平板系統，當入射光之頻率與波向量符合激發平板系統之表面電漿共振條件時，在金屬或負折射物質中以及其與周圍介電物質介面處之電場強度將有明顯增強的現象，此外，我們也可以看出，配合適當的入射光條件與金屬或負折射物質平板之厚度，將可以使平板系統達到一個最大的表面電漿共振強度。In this thesis we investigate the surface plasmon resonance properties of a metal (Al) or negative refraction material slab. We use transfer matrix method to calculate the attenuated total reflection (ATR) spectrum and field distribution of the slab material. Calculated results show the field intensity has been enhanced within and at the boundary of the slab material when the frequency and wave vector of incident light correspond to the surface plasmon resonance condition. In conclusion, we found that with proper thickness of slab and light frequency the strength of surface plasmon resonance can be a maximum.致謝......................................................I
中文摘要.................................................II
英文摘要................................................III
目錄 ....................................................IV
圖目錄 ..................................................VI
表目錄 ..................................................XI
第一章 序論 ………………………………………………………… 1
1-1 前言 …………………………………………………………… 1
1-2 研究動機………………………………………………………… 3
參考資料……………………………………………………………… 6
1-3表面電漿之應用 ………………………………………………… 8
參考資料……………………………………………………………… 10
第二章 基本電磁理論 ……………………………………………… 12
2-1 光與物質交互作用 …………………………………………… 12
(a) 介電物質………………………………………………………… 14
(b) 金屬 …………………………………………………………… 21
(c) 尺寸效應的影響 ……………………………………………… 30
(d) Fresnel 關係式 ……………………………………………… 31
2-2 金屬表面電漿 ………………………………………………… 37
(a) 金屬塊材的電漿模態 ………………………………………… 37
(b) 金屬的表面電漿模態 ………………………………………… 40
(c) 有限厚度平板的表面電漿模態 ……………………………… 47
2-3 負折射物質(左手物質)介紹 ………………………………… 52
參考資料…………………………………………………………… 65
第三章 平板系統的表面電漿探討 ……………………………… 66
3-1 計算與模擬方法 ……………………………………………… 66
3-2 金屬平板系統 ………………………………………………… 71
(a) 對稱結構之金屬平板系統 (玻璃/鋁金屬/玻璃) ……… 71
(b) 非對稱結構之金屬平板系統 (玻璃/鋁金屬/空氣) …… 83
3-3 負折射物質(左手物質)平板系統 …………………………… 87
(a) 對稱結構之負折射物質平板系統 (玻璃/負折射物質/玻璃) …………………………………………………………………… 88
(b) 非對稱結構之負折射物質平板系統 (玻璃/負折射物質/空氣) …………………………………………………………………… 93
參考資料……………………………………………………………… 97
第四章 結論與展望 ………………………………………………… 9
Multiple metallic-shell nanocylinders for surface-enhanced spectroscopes
Full text linkAbstractThe optical properties of multiple dielectric-core-gold-shell nanocylinder pairs are investigated by two-dimensional finite difference time domain method. The core-shell cylinders are assumed to be of the same dimension and composition. For normal incidence, the diffraction spectra of multiple cylinder pairs contain the lightning-rod plasmon mode, and the electric field intensity is concentrated in the gap between the nanocylinder pairs in the infrared region. The resonance wavelength and local field enhancement of this plasmon mode can be tuned by varying the pair-distance between the pairs, the gap-distance between the pairs, and the optical constants of the dielectric-core and the surrounding medium. The results show that the multiple core-shell nanocylinder pair contains the plasmon mode same as that of the solid metallic cylinder pairs at the long wavelength part of the spectrum. The large electric field intensity in the infrared region at long wavelength makes multiple core-shell cylinders as ideal candidates for surface-enhanced spectroscopes.</jats:p
Surface plasmon polariton coupling between nano recording marks and their effect on optical read-out signal
No full textHotspot Analysis of Spatial Environmental Pollutants Using Kernel Density Estimation and Geostatistical Techniques
Full text linkConcentrations of four heavy metals (Cr, Cu, Ni, and Zn) were measured at 1,082 sampling sites in Changhua county of central Taiwan. A hazard zone is defined in the study as a place where the content of each heavy metal exceeds the corresponding control standard. This study examines the use of spatial analysis for identifying multiple soil pollution hotspots in the study area. In a preliminary investigation, kernel density estimation (KDE) was a technique used for hotspot analysis of soil pollution from a set of observed occurrences of hazards. In addition, the study estimates the hazardous probability of each heavy metal using geostatistical techniques such as the sequential indicator simulation (SIS) and indicator kriging (IK). Results show that there are multiple hotspots for these four heavy metals and they are strongly correlated to the locations of industrial plants and irrigation systems in the study area. Moreover, the pollution hotspots detected using the KDE are the almost same to those estimated using IK or SIS. Soil pollution hotspots and polluted sampling densities are clearly defined using the KDE approach based on contaminated point data. Furthermore, the risk of hazards is explored by these techniques such as KDE and geostatistical approaches and the hotspot areas are captured without requiring exhaustive sampling anywhere
A scoring system for the early detection of oral submucous fibrosis based on a self-administered questionnaire
No full textChemical selection rules of single-phase high-entropy oxides
Full text linkHigh-entropy oxides, as a novel research field in ceramics, have been found to present state-of-the-art improvement in various properties. These contributions could be achieved by multiple cations homogeneously occupying the same polyhedral sites, introducing severe lattice distortion throughout a structure. However, the mechanism of chemical selection rules for designing new high-entropy oxides was still unclear. Randomly mixed, multi-components usually form composites instead of a single-phase, solid solution. In this research, twenty high-entropy lanthanide candidates were synthesized and examined to explore the function of two potential parameters: (1) cation size mismatch, and (2) preferred valence states.
The oxide candidates were synthesized by the polymeric steric entrapment method to ensure homogeneous mixing among the cations. The evolution of phase transformation and structural stability from room temperature up to ~2000C were examined in a quadrupole lamp furnace and conical nozzle levitator at synchrotron X-ray facilities. The thermal expansion behaviors of single-phase, high-entropy, lanthanide oxides were measured.
Cation size mismatch and preferred valence configurations have significant influences on the formation of high-entropy oxides. In most of circumstances, mixing cations with excess threshold in size mismatch (δ > 7) caused the formation of secondary phase(s), leading to failure in forming stable, single-phase, high-entropy oxides. By choosing cations with different preferences in valence configurations, the final structure could be constructed for a prototype with a similar combination of oxidation states. Furthermore, merging cations with different valence states could trigger phase transformations/separations during heat treatments. However, in high-entropy oxides, the contribution from configurational mixing entropy was thought to be negligible. Understanding the function of cation size mismatch and preferred valence configurations can benefit the ceramic community in the future when designing high-entropy oxides.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-05-01The student, Kuo-Pin Tseng, accepted the attached license on 2020-05-03 at 18:50.The student, Kuo-Pin Tseng, submitted this Dissertation for approval on 2020-05-03 at 19:48.This Dissertation was approved for publication on 2020-05-05 at 16:54.DSpace SAF Submission Ingestion Package generated from Vireo submission #15180 on 2020-08-25 at 17:29:32Made available in DSpace on 2020-08-26T23:58:36Z (GMT). No. of bitstreams: 2
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Previous issue date: 2020-05-05Embargo set by: Seth Robbins for item 115761
Lift date: 2022-08-26T23:58:55Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
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