Search results for " optical spectroscopy"

Optical properties of biocompatible polyaniline nano-composites

2006

Abstract Polyaniline (PANI) is an electro-active polymer of great interest thanks to its outstanding physical and chemical properties which make it suitable for various applications in optics, bioelectronics, biosensors, diagnostics and therapeutic devices. Unfortunately, PANI is infusible and insoluble in most common solvents and, thus, very difficult to process. In the attempt of improving processability, yet preserving its interesting properties, PANI has been synthesized in the form of particles and dispersed into a hydrogel matrix. The synthesis of PANI–hydrogel composites proceeds via γ-irradiation of PANI dispersions as obtained by ‘in situ’ polymerization of aniline in the presence …

Deposition of High Quality Indium Tin Oxide Films by Monitoring InO Emission Lines

2001

Photosensitivity of SiO2–Al and SiO2–Na glasses under ArF (193 nm) laser

2009

Abstract Photosensitivity of SiO 2 –Al and SiO 2 –Na glass samples was probed by means of the induced optical absorption and luminescence as well as by electron spin-resonance (ESR) after irradiation with excimer-laser photons (ArF, 193 nm). Permanent visible darkening in the case of SiO 2 –Al and transient, life time about one hour, visible darkening in the case of SiO 2 –Na was found under irradiation at 290 K. No darkening was observed at 80 K for either kind of material. This investigation is dedicated to revealing the electronic processes responsible for photosensitivity at 290 and 80 K. The photosensitivity of both materials is related to impurity defects excited directly in the case …

Protein dynamics: conformational disorder, vibrational coupling and anharmonicity in deoxy-hemoglobin and myoglobin.

1993

In this work we study the temperature dependence of the Soret band lineshape of deoxymyoglobin and deoxyhemoglobin, in the range 300-20 K. To fit the measured spectra we use an approach originally proposed by Champion and coworkers (Srajer et al. 1986; Srajer and Champion 1991). The band profile is modelled as a Voigt function that accounts for the coupling with low frequency vibrational modes, whereas the coupling with high frequency modes is responsible for the vibronic structure of the spectra. Moreover, owing to the position of the iron atom out of the mean heme plane, inhomogeneous broadening brings about a non-Gaussian distribution of 0-0 electronic transition frequencies. The reporte…

New Developments in the Production and Research of Actinide Elements

2022

Atoms 10(2), 61 (2022). doi:10.3390/atoms10020061

Radiation hardening of Rare-Earth doped fiber amplifiers

2012

We investigated the radiation hardening of optical fiber amplifiers operating in space environments. Through a real-time analysis in active configuration, we evaluated the role of Ce in the improvement of the amplifier performance against ionizing radiations. Ce-codoping is an efficient hardening solution, acting both in the limitation of defects in the host glass matrix of RE-doped optical fibers and in the stabilization of lasing properties of the Er3+-ions. On the one hand, in the nearinfrared region, radiation induced attenuation measurements show the absence of radiation induced P-related defect species in host glass matrix of the Ce-codoped active fibers; on the other hand, in the Ce-…

Simultaneous Determination of Caffeine and Chlorogenic Acids in Green Coffee by UV/Vis Spectroscopy

2017

A simple method for the simultaneous determination of caffeine and chlorogenic acids content in green coffee was reported. The method was based on the use of UV/Vis absorption. It is relevant that the quantification of both caffeine and chlorogenic acids was performed without their preliminary chemical separation despite their spectral overlap in the range 250–350 nm. Green coffee was extracted with 70% ethanol aqueous solution; then the solution was analyzed by spectroscopy. Quantitative determination was obtained analytically through deconvolution of the absorption spectrum and by applying the Lambert-Beer law. The bands used for the deconvolution were the absorption bands of both caffein…

In situ monitoring of pulsed laser indium–tin-oxide film deposition by optical emission spectroscopy

2001

We performed optical emission spectroscopy to monitor the plasma produced during the ablation of indium-tin-oxide targets under different oxygen pressure conditions using a pulsed UV laser. Molecular bands of InO were identified in the fluorescent spectra produced by pulsed laser ablation. InO line monitoring allowed obtaining the optimal conditions for good-quality ITO film deposition. We demonstrated that it is possible to correlate InO line spectroscopic parameters with the conditions required to fabricate a high-conductivity and high-transparent ITO thin film. In particular, low resistivity (10-4 to 10-3 Ω cm) was obtained in films deposited at room temperature by regulating oxygen pres…

Ag11(SG)7 : A New Cluster Identified by Mass Spectrometry and Optical Spectroscopy

2014

We report a one-step and high yield synthesis of a red-luminescent silver cluster with the molecular formula, Ag11(SG)7 (SG: glutathionate) via reduction of silver ions by sodium borohydride in the presence of the tripeptide, glutathione (GSH). The as-prepared cluster shows prominent absorption features at 485 and 625 nm in its UV-vis absorption spectrum. Aging of the as-prepared cluster solution led to the disappearance of the 625 nm peak, followed by broadening of the 485 nm peak to give three maxima at ?487, 437, and 393 nm in its absorption spectrum. These peaks remain unchanged even after polyacrylamide gel electrophoresis (PAGE), where a single band was observed confirming high purity…