Search results for "uv spectroscopy"
showing 6 items of 6 documents
Titration of poly(dA-dT).poly(dA-dT) in solution at variable NaCl concentration
2004
CD and uv absorption data showed that high molecular weight poly(dA-dT) poly(dA-dT), at 298 K, undergoes an acid-induced transition from B-double helix to random coil in NaCl solutions of different concentrations, ranging from 0.005 to 0.600M. Similarly, titration of the polynucleotide with a strong base causes duplex-to-single strands transition. The base- and acid-induced transitions were both reversible by back-titration (with an acid or, respectively, with a base): the apparent pKa were the same in both directions. However, the number of protons per titratable site (adenine N1) required to reach half-denaturation was in great excess over the stoichiometric value; to a much larger extent…
Spectrophotometric estimation of bicalutamide in tablets
2007
A simple, sensitive, rapid, accurate and precise spectrophotometric method has been developed for the estimation of bicalutamide in bulk and pharmaceutical dosage forms. Bicalutamide shows maximum absorbance at 272 nm with molar absorptivity of 2.3399×10(4) l/mol/cm. Beer's law was obeyed in the concentration range of 1.5-18 μg/ml. The limit of detection and limit of quantification were found to be 0.1 and 0.4 μg/ml, respectively. Results of analysis were validated statistically and by recovery studies.
Luminescence and vacuum ultraviolet excitation spectroscopy of cerium doped Gd3Ga3Al2O12 single crystalline scintillators under synchrotron radiation…
2020
Authors gratefully acknowledge the financial support from the Latvian Science Council grant LZP-2018/2-0358 . The research leading to this result has been supported by the project CALIPSO plus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON2020 . The work of A.P.K. was supported by the Ministry of Science and Higher Education of the Russian Federation , state contracts No. 11.6181.2017/ITR .
Electronic excitations in ZnWO4 and ZnxNi1−x WO4 (x = 0.1 − 0.9) using VUV synchrotron radiation
2011
The photoluminescence spectra and luminescence excitation spectra of pure microcrystalline and nano-sized ZnWO4 as well as the Zn x Ni1−x WO4 solid solutions were studied using vacuum ultraviolet (VUV) synchrotron radiation. The samples were also characterized by x-ray powder diffraction. We found that: (i) the shape of the photoluminescence band at 2.5 eV, being due to radiative electron transitions within the [WO6]6− anions, becomes modulated by the optical absorption of Ni2+ ions in the Zn x Ni1−x WO4 solid solutions; and (ii) no significant change in the excitation spectra of Zn0.9Ni0.1WO4 is observed compared to pure ZnWO4. At the same time, a shift of the excitonic bands to smaller en…
Effect of spatial distribution of impurity ions on the signal of ‘C/O monitor for Wendelstein 7-X’ - an indicator of plasma wall interactions
2022
The ‘C/O monitor’ is a dedicated diagnostic system designed to monitor light impurities (B, C, N and O) in the Wendelstein 7-X (W7-X) stellarator. Its main goal is to provide fast (∼1 ms) information about the impurity level which is measured from a large plasma volume (high throughput). Its first subsystem dedicated to measure Lyman-α lines of H-like carbon (C5+ − 3.4 nm – used as PFC material) and oxygen (O7+ − 1.9 nm – common impurity absorbed by inner vessels’ walls) is going to be commissioned during the next Operational Phase of W7-X. Since the radiated photon intensity of a given impurity depends strongly on plasma kinetic parameters (Te, ne) and impurity transport, it is important t…
Analysis of metallic impurity content by means of VUV and SXR diagnostics in hybrid discharges with hot-spots on the JET-ITER-like wall poloidal limi…
2019
In preparation for the upcoming JET D-T campaign, great effort has been devoted during the 2015-2016 JET campaigns with the ITER-like wall (ILW) to the extension of the high performance H-mode phase in baseline and hybrid scenarios. Hybrid discharges were the only ones that have been stopped by the real-time vessel protection system due hot-spot formation on the outboard poloidal limiter. Generation of hot-spots was linked to the application of high neutral beams injection and ion cyclotron resonance heating (ICRH) power. In tokamaks with high-Z plasma components, the use of ICRH heating is also accompanied by an increased metallic impurity content. Simultaneous control of hot-spot temperat…