In-situ Raman Spectroscopy and Laser-induced Fluorescence of High Vibrationally-excited Gas Mixtures During Laser-induced Chemical Vapor Deposition of Nanostructured Materials PDF Download

Author: Willem Frederik Adrianus Besling (Chemotechniker)
Publisher:
ISBN: 9789074445467
Category :
Languages : en
Pages : 158

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Author: Dimitris Davazoglou
Publisher:
ISBN:
Category : Chemical vapor deposition
Languages : en
Pages : 1240

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Author: Materiaalkunde Instituut Delft Eindhoven Groningen
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 226

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Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 1246

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Author: Steven Aragon
Publisher:
ISBN:
Category : Chemical reaction, Conditions and laws of
Languages : en
Pages : 910

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Author: P. P. Pashinin
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 252

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Author: Xiaofei Liu
Publisher:
ISBN:
Category : Laser spectroscopy
Languages : en
Pages : 220

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Book Description
Spectroscopic laser-based diagnostics are applied in the gas-phase synthesis of nanostructrued materials to make non-intrusive, in-situ, spatially-precise measurements of gas-phase temperatures and relevant chemical species. For the nanomaterials themselves, a novel application of Raman spectroscopy is developed to characterize nanoparticles in-situ, during flame and plasma synthesis. As result, the local conditions for gas-phase synthesis can be determined for a given nanomaterial property, so that fundamental mechanisms can be revealed and process conditions can be optimized. The synthesis configurations investigated in this work are (i) the inverse co-flow diffusion flame (IDF), (ii) the counter-flow diffusion flame (CDF), (iii) the low-pressure burner-stabilized premixed stagnation-point flame, and (iv) the inductively-coupled plasma (ICP) impinging on a cold substrate. Spontaneous Raman spectroscopy (SRS) is used to measure local gas-phase conditions in the 2-D axi-symmetric IDF and the quasi 1-D CDF, where nanomaterials are grown on inserted substrates of various compositions. Nitrogen-diluted methane-air flames are examined. Carbon nanotubes (CNTs) are grown catalytically on metal-alloy substrates, and their morphologies are correlated with the local gas-phase temperature and the concentrations of carbon-based precursor species (e.g. C2H2, CO). Zinc oxide (ZnO) nanostructures are grown directly on zinc-plated steel substrates, and their morphologies are correlated with the local gas-phase temperature and the concentrations of oxidative (e.g. O2, H2O, and CO2) and reducing (e.g. H2) species. Computational simulations in 1-D, involving detailed chemical kinetics and transport properties, and in 2-D, using simplified kinetics and transport, are used to validate and improve the measurements. Laser-induced fluorescence (LIF) is employed to measure the gas-phase temperature profile and OH radical species concentration distribution in a low-pressure, premixed, nitrogen-diluted hydrogen-oxygen, burner-stabilized, stagnation-point flame. Titania nanoparticles are synthesized using a metalorganic precursor. The LIF measurements are compared with computational simulations with detailed chemical kinetics and transport, to affirm the quasi 1-D flow field, as well as to investigate the effects of precursor addition and uniform electric-field application. SRS is utilized to characterize in-situ the composition and crystallinity of nanoparticles, in aerosol form, produced in the aforementioned low-pressure premixed flame and in the ICP synthesis setup. The Stokes spectra are identified for crystalline phases of TiO2 (and Al2O3 in a different flame setup) and c-BN based on ex-situ-taken spectra from the literature. The in-situ technique is able to delineate the phase conversion of nanoparticles (including amorphous to crystalline) as they evolve in the flow field.

Author: Liu, Xin
Publisher: KIT Scientific Publishing
ISBN: 3731503700
Category : Technology (General)
Languages : en
Pages : 248

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This work presents the application of organic semiconductor distributed feedback laser as free-space excitation source in Raman spectroscopy. Surface-enhanced Raman scattering effect is exploited to improve the detection sensitivity. The SERS conditionis achiedved by using substrates consisting of gold-coated polymeric nanopillar arrays. The organic-laser-excited SERS measurements are applied to verify the concentration variation of biomolecule adenosine in aqueous solutions.

Author: Matthieu Baudelet
Publisher: Elsevier
ISBN: 085709873X
Category : Technology & Engineering
Languages : en
Pages : 601

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Book Description
Laser spectroscopy is a valuable tool for sensing and chemical analysis. Developments in lasers, detectors and mathematical analytical tools have led to improvements in the sensitivity and selectivity of spectroscopic techniques and extended their fields of application. Laser Spectroscopy for Sensing examines these advances and how laser spectroscopy can be used in a diverse range of industrial, medical, and environmental applications. Part one reviews basic concepts of atomic and molecular processes and presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation. In addition, it explains the selectivity, sensitivity, and stability of the measurements, the construction of databases, and the automation of data analysis by machine learning. Part two explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media. These chapters discuss imaging methods using laser-induced fluorescence and phosphorescence spectroscopies before focusing on light detection and ranging, photothermal spectroscopy and terahertz spectroscopy. Part three covers a variety of applications of these techniques, particularly the detection of chemical, biological, and explosive threats, as well as their use in medicine and forensic science. Finally, the book examines spectroscopic analysis of industrial materials and their applications in nuclear research and industry. The text provides readers with a broad overview of the techniques and applications of laser spectroscopy for sensing. It is of great interest to laser scientists and engineers, as well as professionals using lasers for medical applications, environmental applications, military applications, and material processing. Presents the fundamentals of laser technology for controlling the spectral and temporal aspects of laser excitation Explores laser spectroscopy techniques, including cavity-based absorption spectroscopy and the use of photo-acoustic spectroscopy to acquire absorption spectra of gases and condensed media Considers spectroscopic analysis of industrial materials and their applications in nuclear research and industry

Author: Marshall Lapp
Publisher: Springer Science & Business Media
ISBN: 1468421034
Category : Science
Languages : en
Pages : 387

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Book Description
The Laser Raman Workshop on the r"eas urement of Gas Properti es i sone of aseries of occasional meetings organized in an informal workshop format through the stimulation of Project SQUID, Office of Naval Research. This workshop is the second to be organized on gas-phase applications of Raman scattering. Both Raman workshops were supported by Project SQUID, ONR, and the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base. The first Raman Workshop was held at the AVCO Everett Research Laboratory, Everett, Massachusetts, with their co-sponsorship in January 1972 under the chairmanship of D. A. Leonard. The present meeting was co-sponsored by the General Electric Research and Development Center, and held at their facility in Schenectady, New York. We are grateful to Project SQUID, AFAPL, and GE for their generous financial support of this Workshop, and to Project SQUID for underwriting the publication costs of the Proceedings. As is always the case for successful meetings, many people contributed substantially to the organization and execution of this workshop. Professor Robert Goulard supported, aided, and encouraged us in the most helpful ways, and we are indebted to him. We received further valuable support and assistance from Dr. Ralph Roberts, Director, and Mr. James R. Patton, Jr., of the Power Branch, Office of Naval Research; from Dr. William H. Heiser, Chief Scientist of the Aero Propulsion Laboratory; and from Dr. James M.