Search results for "RAMAN"
showing 10 items of 1328 documents
Modified Graphene Sheet Stacks for Hydrogen Binding
2017
Results are partially obtained using infrastructure of Lithuanian Energy Institute with support of COST Action MP1103 “Nanostructured materials for solid-state hydrogen storage”. Latvian National Research program IMIS2 is greatly acknowledged for financial support
Archaeometric Characterisation of Decorated Pottery from the Archaeological Site of Villa dei Quintili (Rome, Italy): Preliminary Study
2019
This work focused on the study of decorated pottery dated back to the 16th century from the Roman archaeological site of Villa dei Quintili, a monumental complex located in the south-eastern part of Rome (Italy). A minero-petrographic and geochemical study was undertaken to analyse five archaeological samples in order to define textural features and raw materials used for their production, along with the chemical and physical composition of the superficial decorative glazed coatings. For this purpose, different analytical methods were used, such as polarising optical microscope (POM), X-ray diffraction (XRD), micro-Raman spectroscopy, X-Ray fluorescence (XRF), and electron microprobe analys…
Raman Spectroscopy Technology to Monitor the Carotenoids in Skin of Thalassemia Patients: A Novel Non-Invasive Tool Relating Oxidative Stress with Ir…
2014
In this work we approach the relationship between redox state and iron overload by noninvasive instrumental techniques. Intracardiac, liver iron and liver fibrosis have been monitored in transfusion-dependent thalassemia patients by magnetic resonance imaging and hepatic transient elastography examinations. These measurements have been matched with a non-invasive, and yet unexplored in clinical practice, evaluation of body’s oxidative stress through measurement of antioxidant carotenoids in skin, by a spectroscopic method based on Raman technology (RRS). The global body’s antioxidant status results from a balance between the level of antioxidants in cells and body fluids, including blood, a…
An Iranian booklet: non destructive examination by Energy Dispersive X-Ray Diffractometry and Micro-Raman Spectroscopy
2009
Energy Dispersive X-Ray Diffractometry was used in combination with micro-Raman Spectroscopy to study an undated illuminated Iranian booklet. In both cases, no preliminary preparation of the samples was needed: the data were acquired in a non-destructive way in a natural environment. The book is of particular interest because of the unusual presence of miniatures on some pages. The two techniques were used to collect data from small areas of the pages and in different regions of the miniature in order to identify inks and pigments and to attempt chronological assignment. Raman spectra were affected by strong background fluorescence. In spite of this, different peaks were detected and identi…
Characterisation of component pigments in a mixture
2011
This work is part of Raman spectra database constitution of pigments and materials of Cultural Heritage interest for polychrome artworks characterization. The colours of paintings are often obtained mixing pigments of palette artist’s. The attribution of a work of art to an author and the individuation of fakes are related to the identification of used pigments and also to the detection of mixture constituents. The main research objective is the extension of PH3DRA laboratory database with information useful to detect not only each single pigment but also quantitative data regarding its relative ratio in the examined mixture. The availability of spectra as revealed represents the primary li…
Structural studies of dielectric polymer nanocomposites
2013
A constant need for the development of new and superior materials is always present; for example, a better electrical insulator would enable more efficient use of electrical power. Polymeric nanocomposites, i.e. nanodielectrics, are thought to have unique electrical properties. The basic chemical constitution of a material alone fails to provide an understanding of how desired properties of a material originate or predict the long term behavior of a material. We need to define the structure behind the functionality of a material. To do that, the structure of the material must be studied on several scales. This research was part of the Finnish Funding Agency for Technology and Innovation (TE…
Composición, estructura interna y transporte electrónico de nanohilos individuales de In1-xGaxN e InN
2014
La posibilidad de sintonizar la banda prohibida de las aleaciones de In1-xGaxN desde el UV al IR variando x desde 0 a 1 es la base para potenciales aplicaciones de esta aleación como diodos emisores de luz (LEDs), del inglés “light emitting diodes”, diodos láser (LDs), del inglés “laser diodes” o células solares. Sin embargo, las inhomogeneidades en la composición y la segregación de fases, debido no sólo a la fata de sustratos con coeficientes de expansión térmica que se ajusten a los del InN y el GaN, sino también a la baja temperatura de disociación del InN comparada con la del GaN, dificulta el crecimiento de capas de alta calidad en todo el rango de composiciones. Con el objetivo de su…
Characterisation of single semiconductor nanowires by non-destructive spectroscopies
2015
Los nanohilos semiconductores (NWs, de su nombre inglés, nanowires) tienen una amplia gama de aplicaciones en el campo de la optoelectrónica (emisores de luz y diodos láser), nano-electrónica (circuitos lógicos y transistores de efecto de campo), y detección y producción de energía (células solares). En términos generales, los NWs pueden ser descritos como nanoestructuras de forma alargada con diámetros que van típicamente de decenas a cientos de nanómetros, y con longitudes que oscilan desde pocas hasta las decenas de micras. Dicha morfología ofrece dos ventajas principales en comparación con las capas: su alta relación superficie-volumen y su mayor calidad cristalina, ambas beneficiosas p…
Optical Properties of III-V Nanowires and Their Application for Charge Transport and Single-Photon Emission
2012
This work covers the optical characterization of III-V semiconductor nanowires and their application for charge transport and for single-photon emission. InAs nanowires have been investigated by Raman scattering and PL spectroscopy. The possibility to grow nanowires with a crystal structure different from its bulk counterpart has aroused a lot of interest in their optical and electronic properties. Here, the optical phonon modes of wurtzite InAs nanowires have been studied by polarized Raman scattering. For the first time, Raman measurements on a single InAs nanowire have revealed the A1(TO) and E2h optical phonon modes of the wurtzite structure. Additional resonant Raman scattering experim…
Fabrication techniques for developing a functional microfluidic glass device suitable for detection in optical spectroscopy system
2012
Microfluidic devices offer the chance to manipulate and analyze fluids including bioassays and chemical reactions. In this study, a method to develop a microfluidic analysis system is proposed for detection of nanotubes by a Raman acquisition setup. Microchannels where fabricated in sodalime glass substrate by MeV ion beam lithography or electron beam lithography and wet etching. Fusion bonding (550 °C) was used to seal the microchannels. As a result a prototype microfluidic device with 1.6 µm deep channel that exhibit efficient sealing and suitable channel geometry was obtained. The microfluidic device was tested in a Raman spectroscopy detection system and the collected spectra showed the…