Search results for " absorption"

Effects induced by UV laser irradiation on pure silica core multimode optical fibers investigated by in situ optical absorption measurements

2010

Characterization of a cylindrical plastic β-detector with Monte Carlo simulations of optical photons

2017

In this work we report on the Monte Carlo study performed to understand and reproduce experimental measurements of a new plastic β-detector with cylindrical geometry. Since energy deposition simulations differ from the experimental measurements for such a geometry, we show how the simulation of production and transport of optical photons does allow one to obtain the shapes of the experimental spectra. Moreover, taking into account the computational effort associated with this kind of simulation, we develop a method to convert the simulations of energy deposited into light collected, depending only on the interaction point in the detector. This method represents a useful solution when extens…

Silver Sulfide Nanoclusters and the Superatom Model

2015

The superatom model of electron-shell closings has been widely used to explain the stability of noble-metal nanoclusters of few nanometers, including thiolate-protected Au and Ag nanoclusters. The presence of core sulfur atoms in silver sulfide (Ag–S) nanoclusters renders them a class of clusters with distinctive properties as compared to typical noble-metal clusters. Here, it is natural to ask whether the superatom model is still applicable for the Ag–S nanoclusters with mixed metal and nonmetal core atoms. To address this question, we applied density functional simulations to analyze a series of Ag–S nanoclusters: Ag14S(SPh)12(PPh3)8, Ag14(SC6H3F2)12(PPh3)8, Ag70S16(SPh)34(PhCO2)4(triphos…

UV filters: From sunscreens to human body and the environment

2007

Recognition of the harmful effects of ultraviolet (UV) radiation on the skin has triggered development of organic chemicals (commonly referred as UV filters) that can absorb UV radiation and attenuate the negative effects of sunlight exposure. Depending on the properties and the intended degree of protection, a wide array of combinations is being marketed as delivering protection against most kinds of UV-induced skin damage. However, some UV filters have dermatological implications, so maximum applicable concentrations have been established. To monitor to what extent commercial products comply with the mandatory limits, several analytical methods have been used for their determination in co…

Biological Monitoring Using Lichens as a Source of Information About Contamination of Mountain with Heavy Metals

2022

Abstract The aim of this study was passive biomonitoring of the mountains of southern Poland. Lichens Hypogymnia physodes were used for the study. Concentrations of the heavy metals Ni, Cu, Zn, Cd and Pb were determined in these lichens. The concentrations were measured by atomic absorption spectrometry (AAS). The analysis of the concentrations of the determined heavy metals in the lichen thallus allowed to determine the places with the highest and the lowest contamination with a given heavy metal in the study area. It was shown that the area of Great Czantoria and Big Soszow is the most contaminated with heavy metals among the investigated areas. The study shows that the transport of analy…

Molecular spectra of liquors as method of studying delignification process

2011

FTIR-spectra of dried compounds of black liquors after aspen kraft cooks of different duration were obtained. Twelve samples corresponding to changing H-factor value in limits 4-1010 were investigated. The parameters of selected bands corresponding to lignin fragments vibrations were calculated using mathematical treatment methods. It was revealed that the positions and bandwidths of these lignin bands did not change. During cook at the first stage (H-factor values 4-200) their intensities strongly increased with different rates. During the next time period when the H-factor values were more than 200 a slow phase with small changes of the bands intensities were revealed. The IR-spectra of b…

Strongly Coupled Coherent Phonons in Single-Layer MoS 2

2019

We present a transient absorption setup combining broadband detection over the visible-UV range with high temporal resolution ($\sim$20fs) which is ideally suited to trigger and detect vibrational coherences in different classes of materials. We generate and detect coherent phonons (CPs) in single layer (1L) MoS$_2$, as a representative semiconducting 1L-transition metal dichalcogenide (TMD), where the confined dynamical interaction between excitons and phonons is unexplored. The coherent oscillatory motion of the out-of-plane $A'_{1}$ phonons, triggered by the ultrashort laser pulses, dynamically modulates the excitonic resonances on a timescale of few tens fs. We observe an enhancement by…

Photocycle of point defects in highly- and weakly-germanium doped silica revealed by transient absorption measurements with femtosecond tunable pump.

2022

AbstractWe report pump-probe transient absorption measurements addressing the photocycle of the Germanium lone pair center (GLPC) point defect with an unprecedented time resolution. The GLPC is a model point defect with a simple and well-understood electronic structure, highly relevant for several applications. Therefore, a full explanation of its photocycle is fundamental to understand the relaxation mechanisms of such molecular-like systems in solid state. The experiment, carried out exciting the sample resonantly with the ultraviolet (UV) GLPC absorption band peaked at 5.1 eV, gave us the possibility to follow the defect excitation-relaxation dynamics from the femto-picosecond to the nan…

Study of the thermochromic phase transition in CuMo1−xWxO4 solid solutions at the W L3-edge by resonant X-ray emission spectroscopy

2021

This is the peer reviewed version of the following article: I. Pudza, A. Kalinko, A. Cintins, A. Kuzmin, Acta Mater. 205 (2021) 116581, which has been published in final form at https://www.sciencedirect.com/science/article/abs/pii/S1359645420310181 This article may be used for non-commercial purposes in accordance with Elsevier Terrms and Conditions for Self-Archiving.

Application of algae in active biomonitoring of the selected holding reservoirs in swietokrzyskie province

2016

During the years 2014-2015, biomonitoring studies were carried out at three holding reservoirs located in Swietokrzyskie Province (central Poland): Kielce artificial lake, Chancza reservoir and Sielpia reservoir. In sea water algae Palmaria palmata (Linnaeus) Weber & Mohr, exposed in the analysed waters, the increases of concentrations were determined by the atomic absorption spectrometry method (AAS), of the following: Mn, Fe, Cu, Zn, Cd and Pb. Conductivity and pH were also determined in the reservoirs waters. The differences between the increases of heavy metal concentrations in the samples of algae found along the coastline were indicated; they result from different distances from the p…