• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 584
  • 67
  • 48
  • 35
  • 16
  • 9
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 885
  • 885
  • 100
  • 98
  • 81
  • 76
  • 75
  • 68
  • 66
  • 65
  • 64
  • 62
  • 62
  • 61
  • 60
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

CVD synthesis of nitrogen doped carbon nanotubes using iron pentacarbonyl as catalyst

Ghadimi, Nafise 24 February 2012 (has links)
M.Sc., Faculty of Science, University of the Witwatersrand, 2011 / In this dissertation, the synthesis of nitrogen doped carbon nanotubes (N-CNTs) was performed successfully, using a floating catalyst chemical vapour deposition (CVD) method. Fe(CO)5 was utilized as the catalyst and acetonitrile and toluene as nitrogen and carbon sources respectively. Two different procedures were used to add reagents to the reactor: an injection method and a bubbling method. The effect of nitrogen concentration and physical parameters such as reaction temperature, gas flow rate on the morphology, crystallinity and thermal stability of the tubes was studied. The synthesized materials were characterized by means of Raman spectroscopy, TGA and TEM analyses. The presence of nitrogen was confirmed by the presence of the bamboo formations in the tubes by TEM. A comparison of the data from the numerous reactions revealed that N-CNTs can be made from Fe(CO)5 and acetonitrile. Further the main conclusions achieved using the injection method were: i) the maximum number of tubes with bamboo structure were made using on acetonitrile concentration of 15%, ii) The best growth temperature to make N-CNTs was 850 oC, iii) An increase in acetonitrile concentration decreased the yield of NCNTs and iv) Tubes with the narrowest outer diameters were made using an acetonitrile concentration of 15%.
172

Effect of fly ash composition on the synthesis of carbon nanomaterials

Matshitse, Refilwe Manyama Stephina 10 May 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Master of Science. Johannesburg, 2015. / Fly ash is a by-product generated during the combustion of coal for electricity gen- eration. Previous studies have shown that various waste fly-ashes (Japanese, Saudi Arabian, and Australian) contain trace quantities of transition metal elements which can be used in the synthesis of shaped carbon nanomaterials. A survey of the litera- ture has shown that no attempts to correlate the composition of a particular coal fly ash and the type or quantity of carbon nanomaterials (CNMs) that can be synthesized has been made. Neither has the effect of leached fly ash been tested for the synthesis of CNMs. Hence a study on the effect of the chemical composition of South African fly ash (collected from ESKOM’s Duvha power station in Mpumalanga) upon the chemical vapour deposition (CVD) synthesis of carbon nanostructures is justified. Untreated and chemically treated fly ash samples were used as catalysts in the CVD method to synthesize CNMs. In the latter case selective leaching experiments were conducted on the fly ash samples under acidic, basic and neutral conditions. Op- timal CNM synthetic conditions were achieved by initially flowing H2 gas to re- duce the metal oxides within the fly ash catalyst followed by the introduction of the carbon source (C2H2) at a temperature range of 600 - 800 ◦C. All samples were quantitatively and/or qualitatively characterized. Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF) techniques were used to quantify the metal ions which were removed from the fly ash samples. Fur- thermore, qualitative studies were conducted with (PXRD, and laser Raman spec- troscopy), morphological and surface area characterization techniques (SEM, TEM and BET) were used to investigate the synthesis of CNMs from the untreated and chemically treated fly ash samples. Results have shown that carbon nanofibers (CNFs) of different geometric morpholo- gies were synthesized at an optimal yield temperature of 700◦C. A combination of smooth, thin, wide, spiral platelet-like, stacked cup, and fishbone morphologies were reported when the untreated fly ash catalyst was used. Fly ash catalysts under acidic, basic and neutral treatments showed CNFs of varying sizes and specific morpholo- gies. Smooth graphitic platelet-like, stacked cup and platelet-like CNFs were re- ported when the fly ash catalyst was leached with neutral, basic and acidic solutions. Carbon nanofibre sizes with the IG ID ratios were reported as follows 115 nm (1.092), 52 nm (0.799), and 200 nm (0.960) under neutral, basic and acidic mediums respec- tively. Surface areas (41, 14 and 7) m2/g for the CNFs that were synthesised from the neutral, basic and acidic treated fly ash catalysts were related to the selective leaching of metals. The quality and quantity of CNFs obtained under acidic medium were associated with the leaching of iron (5.6%), cobalt (1.7%), calcium (20.4%), copper (12.5%), chromium (4.6%), magnesium (23.3%), manganese (15.2%) and nickel (2%) from the fly ash catalyst. Under a basic medium only chromium (0.2%), calcium (0.3%) and copper (7.4%) were removed. Significantly the best quality of CNFs was ob- tained when fly ash was treated under neutral conditions. Metal ions such as: cal- cium (3.7%), copper (3.8%), chromium (0.1%), and magnesium (1.3%) were mod- erately removed from the ash matrix. Therefore, composition and quantity of the fly ash catalyst had an effect on the synthesis of CNFs.
173

Manufacture and stabilisation of highly concentrated emulsions using polyhedral oligomeric silsesquiozane nanomolecules

Mamedov, Emil January 2015 (has links)
Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The subject of this current study concerns highly concentrated emulsions of the explosive grade. A distinguishing characteristic of these systems is a high internal to external phase volume ratio. The volume fraction of the aqueous phase of such an emulsion generally far exceeds the close packing limit. Continuous phase of the system is a supersaturated aqueous solution of ammonium nitrate inorganic salt. In combination with high internal phase concentration, this inevitably leads to the destabilisation of the system. The thermodynamic instability of such systems is attributed to two major factors: 1) crystallisation of dispersed phase and 2) coalescence of the individual droplets within the bulk. This poses a significant problem since destabilisation of the bulk emulsion in turn leads to partial or complete loss of sensitivity to detonation of the final product of which highly concentrated emulsion is the base. Since the invention of such types of bulk explosives, a considerable and on-going effort has targeted the improvement of the stability of these systems, with a scope primarily focused on the use of various surfactant agents with different properties as well as stabilising mixtures containing numerous surfactants. In recent years, a new approach has been explored: the stabilisation of highly concentrated emulsions with the use of solid fumed silica nanoparticles. This is a promising new field of study, already being implemented by manufacturers and actively developing. The focus of this present study is to investigate and lay the ground work for further research in the principally new approach towards the stabilisation of highly concentrated emulsions with the use of the polyhedral oligomeric silsesquiozane nanomolecules. These are unique compounds possessing hybrid inorganic-organic structures and properties, and carrying a range of advantages over currently implemented surfactants. As opposed to silica nanoparticles, these compounds are not solid particles but can be regarded as molecular silica. This investigation will focus on the general possibility of implementation of such compounds as stabiliser agents for emulsions in general, and highly concentrated emulsions of the explosive grade in particular, and the resultant effects on the stability. Effects on stability will be investigated both when used solely and in combination with common surfactants. In addition, stability both on shelf and under stress will be investigated within the framework of the study.
174

Energy concentration in plasmonic nanostructures: Green function formalism. / 電漿子納米結構中的能量集中: 格林函數方法 / Energy concentration in plasmonic nanostructures: Green function formalism. / Dian jiang zi na mi jie gou zhong de neng liang ji zhong: Gelin han shu fang fa

January 2012 (has links)
各種納米結構的光學反應,已成為一被相當關注的課題,在物理理論和應用技術的層面上被廣泛研究。在本文中,我們利用格林函數方法(GFF),研究了新月形圓柱体和兩接近中的圓柱体的靜電共振。格林函數方法裏涉及一表面積分方程式,我們求該方程的解便可以得出各不同形狀的納米結構的電勢。格林函數方法是一容易使用、高效率的方法,並且在研究納米結構的光學行為的問題上得出準確結果。 / 在論文的第一部分,我們計算了新月形圓柱体和兩接近中的圓柱体的杆光譜,從而研究該兩個結構的靜電共振。然而,當這兩個結構中有接觸點時,系統中便有一奇點,因此我們不能直接使用格林函數方法研究這情況。為了解決這問題,我們首先使用了變換光學的方法,求得該結構的雙極因子,再從中得到其有效介電常數的譜密度。為了比較非接觸情況中離散的杆光譜和接觸情況中的連續杆光譜,我們進一步定義了一累積分佈函數,它是其譜密度的累積分佈函數。我們從而發現當系統由非接觸的情況漸近接觸時,其離散的杆光譜便趨向其相應的連續杆光譜。 / 在論文的第二部分,我們直接研究了新月形圓柱体和兩接近中的圓柱体的勢分佈和電埸分佈。我們發現在新月形圓柱体和兩接近中的圓柱体的系統中,能量會分別將集中於其金屬間隔和空氣間隔附近的區域。當我們適當地選擇系統的參數時,其共振及能量更能進一步增強。我們亦確認了使用格林函數方法和使用保角變換方法兩者得出的結果的是吻合的。我們的研究結果可以幫助設計電漿子捕光裝置。 / The optical responses of various nanostructures have attracted a considerable attention and they have been extensively studied from the theoretical and technological points of view. In this thesis, we have studied the electrostatic resonance of crescent-shaped cylinder and two approaching cylinders by the Green function formalism (GFF). In the GFF, a surface integral equation is formulated for the scalar potential for an arbitrary number of nanostructures of various shapes. GFF is easy to apply and gives accurate results for the optical behaviors of these nanostructures. / In the first part of the thesis, we have studied the electrostatic resonance of crescent-shaped cylinder and two approaching cylinders by calculating the pole spectrum. However, in the touching case, there is a singular point and thus the GFF cannot be applied directly. To circumvent this problem, the spectral density is found from the polarizability of the nanostructure, which can be obtained analytically by the transformation optics approach. To compare the discrete pole spectrum of the non-touching cases with the continuous spectrum of the touching case, we have used the cumulative distribution function of the spectral density. We are then able to show that the discrete pole spectrum approaches to the continuous pole spectrum as the system approaches from non-touching cases to the touching case. / In the second part of the thesis, the electrostatic resonance is investigated by directly finding the local field distributions of crescent and two approaching cylinders under a uniform applied electric field. It is shown that there is an energy concentration within the metal narrow gap and the air narrow gap in the cases of crescent and two approaching cylinders respectively. It is also found that when parameters are carefully chosen, the nanoconcentration of energy will be greatly enhanced. The numerical GFF results are confirmed with the analytic results by conformal transformation. The results are useful in designing plasmonic light-harvesting devices. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yung, Sai Kit = 電漿子納米結構中的能量集中 : 格林函數方法 / 翁世杰. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 71-74). / Abstracts also in Chinese. / Yung, Sai Kit = Dian jiang zi na mi jie gou zhong de neng liang ji zhong : Gelin han shu fang fa / Weng Shijie. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Optical responses in plasmonic systems --- p.1 / Chapter 1.2 --- Objective of the thesis --- p.5 / Chapter 2 --- Review on Green function formalism --- p.7 / Chapter 2.1 --- Integral equation formalism --- p.7 / Chapter 2.2 --- Periodic corrugated interfaces --- p.11 / Chapter 2.3 --- Solution by mode expansion --- p.16 / Chapter 2.4 --- Numerical solution --- p.18 / Chapter 3 --- Pole spectrums of crescent-shaped cylinder and approaching cylinders --- p.21 / Chapter 3.1 --- Review of Green function formalism on the spectral representation of the effective dielectric constant --- p.22 / Chapter 3.2 --- Numerical results --- p.29 / Chapter 3.2.1 --- Spectral representation of the effective dielectric constant of crescent-shaped cylinders --- p.29 / Chapter 3.2.2 --- Spectral representation of the effective dielectric constant of approaching cylinders --- p.37 / Chapter 4 --- Energy concentration of crescent and approaching cylinders --- p.44 / Chapter 4.1 --- Energy concentration of crescent-shaped cylinder --- p.45 / Chapter 4.2 --- Energy concentration of approaching cylinders --- p.53 / Chapter 5 --- Conclusion --- p.58 / Chapter 5.1 --- Suggestion of future works --- p.60 / Chapter A --- Conformal transformation --- p.61 / Chapter A.1 --- Conformal transformation on crescent-shaped cylinder: nontouching case --- p.61 / Chapter A.2 --- Conformal transformation on approaching crescent-shaped cylinders --- p.66 / Bibliography --- p.71
175

Microwave-assisted synthesis and biomedical applications of inorganic nanostructured materials. / CUHK electronic theses & dissertations collection

January 2011 (has links)
A series of interesting core/shell silver/phenol formaldehyde resin (PFR) nano/microstructures were also synthesized through an efficient microwave process by self-assembly growth. Various morphologies, including monodispersed nanospheres, nanocables, and microcages were obtained by changing the fundamental experimental parameters, such as the reaction time and the surfactants (Pluronic P123 or CTAB). The results indicated that the presence of triblock copolymer Pluronic P123 would result in hollow silver/PFR microcages, while CTAB would prefer the formation of ultralong silver/PFR coaxial nanocables. In the absence of surfactants, monodispersed core/shell silver/PFR nanospheres could be obtained. The size of the nanospheres can be controlled in the range of 110 to 450 nm by changing the molar ratio of reagents (phenol:hexamine). The morphology and composition of the as-prepared products were characterized. The formation mechanism of the products was discussed based on the obtained results. / Bifunctional mesoporous core/shell Ag FeNi3 nanospheres were synthesized by reducing iron(III) chloride, nickel(II) chloride and silver nitrate with hydrazine in ethylene glycol under microwave irradiation. The efficient microwave-hydrothermal process significantly shortened the synthesis time to one minute. The toxicity of Ag FeNi3 nanospheres were tested by exposing to zebrafish, they were less toxic than silver nanoparticles. In vitro MRI confirmed the effectiveness of the Ag FeNi3 nanospheres as sensitive MRI probes. The interaction of Rhodamine Band nanospheres showed greatly enhanced fluorescence over the FeNi3 nanoparticles. / Finally, a series of ZnO microarchitectures including monodispersed spindles, branches, flowers, paddies, and sphere-like clusters were prepared by an efficient microwave-hydrothermal process. The ZnO mophologies could be effectively controlled by changing the reaction conditions such as the reaction temperature, the reactant concentrations and the solvent system. Simple microspindles, interesting flowers and paddies could be obtained in the presence of hexamine, and the more attractive sphere-like clusters could be synthesized by introducing phenol. The formation mechanisms of different morphologies are discussed in detail. These interesting ZnO structures may have potential applications in electronic and optoelectronic devices. / Inorganic nanostrucured materials have attracted much attention owing to their unique features and important applications in biomedicine. This thesis describes the development of rapid and efficient approaches to synthesize inorganic nanostructures, and introduces some potential applications. / Magnetic nanostructures, such as necklace-like FeNi3 magnetic nanochains and magnetite nanoclusters, were synthesized by an efficient microwave-hydrothermal process. They were used as magnetic resonance imaging (MRI) contrast agents. Magnetic FeNi3 nanochains were synthesized by reducing iron(III) acetylacetonate and nickel(II) acetylacetonate with hydrazine in ethylene glycol solution without any template under microwave irradiation. This was a rapid and economical route based on an efficient microwave-hydrothermal process which significantly shortened the synthesis time to mins. The morphologies and size of the materials could be effectively controlled by adjusting the reaction conditions, such as, the reaction time, temperature and concentrations of reactants. The morphology and composition of the as-prepared products were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The size of the aligned nanospheres in the magnetic FeNi 3 chains could be adjusted from 150nm to 550nm by increasing the amounts of the precursors. Magnetic measurements revealed that the FeNi3 nanochains showed enhanced coercivity and saturation magnetization. Toxicity tests by exposure of FeNi3 nanochains to the zebrafish larvae showed that the as-prepared nanochains were biocompatible. In vitro magnetic resonance imaging (MRI) confirms the effectiveness of the FeNi 3 nanochains as sensitive MRI probes. Magnetite nanoclusters were synthesized by reducing iron(III) acetylacetonate with hydrazine in ethylene glycol under microwave irradiation. The nanoclusters showed enhanced T2 relaxivity. In vitro and in vivo MRI confirmed the effectiveness of the magnetite nanoclusters as sensitive MRI probes. We also investigated the biodistribution of the nanoclusters in rat liver and spleen. / Jia, Juncai. / Adviser: Jimmy C. Yu. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
176

Growth and assembly of gold nanorods and their interactions with fluorophores and photochromic molecules. / 金納米棒的生長、組裝以及他們與螢光團或光至變色分子的相互作用 / CUHK electronic theses & dissertations collection / Growth and assembly of gold nanorods and their interactions with fluorophores and photochromic molecules. / Jin na mi bang de sheng chang, zu zhuang yi ji ta men yu ying guang tuan huo guang zhi bian se fen zi de xiang hu zuo yong

January 2011 (has links)
I believe that my research work will provide an in-depth understanding of the basic chemical and physical properties of plasmonic gold nanorods. These works can inspire future applications of plasmonic nanostructures on biotechnology, optoelectronics and solar energy conversion. - / I will first introduce my studies on high-index-faceted gold nanocrystals. Elongated tetrahexahedral (THH) gold nanocrystals have been prepared in high yields using a seed-mediated growth method. Structural characterizations reveal that they are single crystals enclosed by 24 high-index facets. Electrochemical measurements have proven that these THH Au nanocrystals are more chemically active than octahedral Au nanocrystals that are enclosed by low-index {1111} facets. Next, I will demonstrate the formation of large-area, 3D ordered assemblies of Au nanostructures that have different sizes and shapes, including nanorods, polyhedra, nanocubes, and bipyramids, by droplet evaporation. The nature of the resultant assemblies is strongly dependent on the shape of Au nanostructures for single-component systems; while the assembly of binary nanorod mixtures is dependent on the relative diameters of two nanorod samples for the nanorods used in our experiments. / Most applications of plasmonic nanostructures are based on their interactions with other chemical/physical species. In my research work, gold nanorods interacting with photochromic molecules and fluorophores are extensively studied. For the case of photochromic molecules, I have demonstrated a plasmonic switch on the basis of the resonance coupling between single Au nanorods and photochromic molecules. An individual plasmonic switch is composed of a single nanorod and the surrounding photochromic molecules. Its modulation depth reaches 7.2 dB. The estimated power and energy required for operating such a single-nanorod plasmonic switch are ∼13 pW and ∼39 pJ. For the case of fluorophores, I will give a systematic description of my research on plasmon-fluorophore interactions. Excitation polarization-dependent plasmon-enhanced fluorescence, polarized emission, and modulation of fluorophore emission spectra by localized plasmon resonances will be experimentally demonstrated. The interactions between the plasmonic nanorods and the fluorophore molecules can be temporally separated into plasmon-enhanced excitation and coupled emission processes under unsaturated excitation conditions. Finite-difference time-domain (FDTD) method will be employed to explain the origin of the excitation and emission polarization dependence. A term "plasmophore", which is corned by Lakowicz et al., is quoted to describe the artificially prepared quantum emitters that are composed of plasmonic structure and fluorophore. / Noble metal nanocrystals have drawn great attention in a wide range of research fields due to their extraordinary localized surface plasmon resonances, which are essentially collective charge density oscillations confined in metallic nanostructures. Their applications range from bioimaging, sensing and therapy in life sciences to plasmonic circuits and optical data storage in micro-optoelectronics. More attractively, they can be used to enhance light harvesting in solar energy conversion systems. In this thesis, I will systematically describe the preparation and assembly of gold nanorods and their interactions with fluorophores and photochromic molecules, both experimentally and theoretically. / Ming, Tian = 金納米棒的生長、組裝以及他們與螢光團或光至變色分子的相互作用 / 明天. / Adviser: Jianfang Wang. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Ming, Tian = Jin na mi bang de sheng chang, zu zhuang yi ji ta men yu ying guang tuan huo guang zhi bian se fen zi de xiang hu zuo yong / Ming Tian.
177

Advanced Applications in Nanophotonics

Yang, Hao January 2019 (has links)
Nanophotonics is a fast-growing area of both scientific significance and practical value for applications. Nanophotonics studies the interaction between light and electronic systems in nanomaterials and nanostructures as well as the behavior of light in nanometer scales. It covers many hot topics such as plasmonics, two-dimensional materials, and silicon photonics. Increasing attention is given to the area and nanophotonics is expected to have significant impact on future technology advances. This thesis work focuses on three aspects of nanophotonics. The first aspect is in exploring the nonlocal effect and surface correction for nanometer-length-scale plasmonic structures. Plasmonics is the study of the interaction between electromagnetic fields and free electrons in a metal. It exploits the unique optical properties of metallic nanostructures to enable routing and manipulation of light at the nanoscale, where nonlocal effect becomes important. Here we introduce a new surface hydrodynamic model for plasmon propagation at interfaces, which incorporates both nonlocality and surface contributions. This surface correction is calculated via a discontinuity in the normal component of the electric displacement in conjunction with Feibelman's d-parameters, thus enabling rapid numerical calculation of nanostructures without requiring a full quantum calculation because of its large computational requirement. We examine numerical calculations of surface plasmon polaritons propagation at a single interface structure, and then for a more complex thin-film structures. The second aspect is investigating the third-harmonic generation in thick multilayer graphene. Graphene is the first two-dimensional material to be discovered and has attracted much interest because of its remarkable two-dimensional electronic, optical, mechanical, and thermal properties. Multilayer graphene, can be seen as stacking of monolayer graphene, and it offers an array of properties that are of interest for optical physics and devices. We describe the layer-dependent for third-harmonic generation in thick multilayer graphene on quartz substrate. The third harmonic signal of multilayer graphene exhibits a complex dependence on its layer number showing that the optimal third harmonic signal at 24 layers, in good agreement with two theoretical models. The third aspect is an exploration in silicon photonics of design and demonstration of a differential phase shift keying demodulator based on coherent perfect absorption effect. Silicon photonics is considered a potential future communication system mainly due to its compact footprint, dense integration, and compatibility with mature silicon integrated circuit manufacturing. Differential phase shift keying based system offers advantages, e.g., dispersion tolerance, improved sensitivity, and does not require coherent detection. Coherent perfect absorption uses a ring resonator works for the critical coupling condition at resonance frequency. This work shows a new compact demodulator circuit can be integrated in all optical-system.
178

Electron microscopy studies of nanomaterials for electrochemical and photoelectrochemical applications

Peng, Xiaoyu January 2015 (has links)
No description available.
179

Nanostructured CU₂O solar cells

Heffernan, Shane January 2015 (has links)
No description available.
180

XPS study of RF-sputtered copper in silicon dioxide. / 透過X光電子譜研究射頻濺射之銅復合物石英 / XPS study of RF-sputtered copper in silicon dioxide. / Tou guo X guang dian zi pu yan jiu she pin jian she zhi tong fu he wu shi ying

January 2003 (has links)
by Leung Kit Sum = 透過X光電子譜研究射頻濺射之銅復合物石英 / 梁潔心. / Thesis submitted in: August 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 77-78). / Text in English; abstracts in English and Chinese. / by Leung Kit Sum = Tou guo X guang dian zi pu yan jiu she pin jian she zhi tong fu he wu shi ying / Liang Jiexin. / Abstract --- p.i / 論文摘要 --- p.iii / Acknowledgement --- p.iv / Table of Content --- p.v / List of Figures --- p.ix / List of Tables --- p.xi / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Nanoparticles and Nanophase Materials --- p.1 / Chapter 1.2 --- Nonlinear Optical Phenomena and Their Physical Origin --- p.4 / Chapter 1.2.1 --- Dielectric Confinement --- p.6 / Chapter 1.2.2 --- Quantum Confinement --- p.8 / Chapter 1.2.2.1 --- Intraband Transition --- p.9 / Chapter 1.2.2.2 --- Interband Transition --- p.9 / Chapter 1.2.2.3 --- Hot-electron Transition --- p.11 / Chapter 1.3 --- Importance of Optical Nonlinearity --- p.11 / Chapter 1.3.1 --- Self-Phase Modulation --- p.11 / Chapter 1.3.2 --- Self-Focusing/Defocusing --- p.12 / Chapter 1.4 --- Sample Preparation --- p.12 / Chapter 1.4.1 --- Sputtering --- p.13 / Chapter 1.5 --- Characterization of Nanocomposites --- p.15 / Chapter 1.6 --- Aim of the Project --- p.15 / References --- p.17 / Chapter CHAPTER 2 --- INSTRUMENTATION / Chapter 2.1 --- Introduction --- p.20 / Chapter 2.2 --- Sputter Deposition --- p.20 / Chapter 2.2.1 --- Glow Discharge --- p.21 / Chapter 2.2.2 --- Radio-Frequency Sputtering (RF Sputtering) --- p.24 / Chapter 2.2.3 --- Magnetically Enhanced Sputtering --- p.24 / Chapter 2.2.4 --- Instrumentation --- p.25 / Chapter 2.2.4.1 --- Target Assemblies --- p.27 / Chapter 2.2.4.2 --- Shutter --- p.28 / Chapter 2.2.4.3 --- Substrate Holder --- p.28 / Chapter 2.2.4.4 --- Power Supply --- p.28 / Chapter 2.2.5 --- Experimental --- p.29 / Chapter 2.3 --- X-ray Photoelectron Spectroscopy (XPS) --- p.29 / Chapter 2.3.1 --- Instrumentation --- p.31 / Chapter 2.3.2 --- Application to metal nanoclusters composite glass --- p.33 / Chapter 2.3.2.1 --- Compositional Analysis --- p.33 / Chapter 2.3.2.2 --- Depth Profiling --- p.33 / Chapter 2.3.3.3 --- Auger Parameters --- p.33 / Chapter 2.4 --- Transmission Electron Microscopy (TEM) --- p.34 / Chapter 2.4.1 --- Sample Preparation --- p.35 / Chapter 2.4.1.1 --- Sample Thickness Determination --- p.35 / Chapter 2.4.1.2 --- Ion Milling --- p.36 / Chapter 2.4.2 --- Instrumentation --- p.36 / Chapter 2.4.3 --- Contrast and Image Formation --- p.38 / Chapter 2.4.3.1 --- Bright and Dark Field Image --- p.38 / Chapter 2.4.3.2 --- Mass and Thickness Contrast --- p.40 / Chapter 2.4.3.3 --- Diffraction Contrast --- p.40 / References --- p.42 / Chapter CHAPTER 3 --- COMPOSITION AND NANUSTRUCTURE OF COPPER DOPED FUSED SILICA / Chapter 3.1 --- Introduction --- p.44 / Chapter 3.2 --- Experiment --- p.45 / Chapter 3.3 --- Results and Discussion --- p.47 / Chapter 3.3.1 --- Effect of Input RF Power on the Growth of Film --- p.47 / Chapter 3.3.2 --- Theoretical Calculation of Cluster Size by Ratio of Surface to Total Amount of Copper --- p.55 / Chapter 3.3.3 --- TEM Studies of Copper Nanoclusters --- p.57 / Chapter 3.3.4 --- Further Discussion: Effect of Current and Voltage on the Determination of Deposition Rate --- p.60 / Chapter 3.3.5 --- Atomic Distribution and Chemical State of Copper Nanocluster --- p.60 / Chapter 3.3.6 --- Effect of Pressure on the Growth of Film --- p.66 / Chapter 3.3.6.1 --- How Pressure Affects Cluster Growth --- p.70 / Chapter 3.3.7 --- Effect of Deposition time on the Growth of Film --- p.71 / Chapter 3.3.7.1 --- How Film thickness Affects Cluster Growth --- p.75 / Chapter 3.4 --- Summary --- p.75 / References --- p.77 / Chapter Chapter 4 --- CONCLUSION AND FUTURE DIRECTIONS / Chapter 4.1 --- Conclusion --- p.79 / Chapter 4.2 --- Future Directions --- p.79 / Chapter 4.2.1 --- Generation of Active Matrix Nanocomposite --- p.79

Page generated in 0.0515 seconds