Search results for "absorptio"
showing 10 items of 2815 documents
High-spin → low-spin relaxation in the two-step spincrossover compound [Fe(pic)3]Cl2EtOH (pic = 2-picolylamine)
1998
Abstract The spin-crossover compound [Fe(pic) 3 ]Cl 2 EtOH (pic = 2-picolylamine) shows an unusual two-step spin transition. This is thought to be caused by specific nearest-neighbour interactions and short-range correlations and requires a theoretical treatment of the elastic interactions between the spin-changing molecules beyond the mean-field approximation. Such short-range correlations also influence the high-spin → low-spin relaxation following the light-induced population of the high-spin state at cryogenic temperatures, leading to characteristic deviations from the predictions of a mean-field treatment. These deviations are directly observable by comparison of the full and unperturb…
Spectroscopic signatures for planar equilibrium geometries in methyl-substituted oligothiophenes
2009
In recent studies it was demonstrated that temperature-dependent optical spectroscopy is a valuable tool for revealing the differences in the geometries of flexible molecules like oligothiophenes (OTs) in the ground (S0) and first excited (S1) electronic states, by examining the symmetry relations between the absorption and emission spectra: while at low temperature the spectra show mirror symmetry, pointing to planar geometries in S0 and S1, the symmetry relation breaks down at ambient temperature due to thermal population of torsional modes. In the present joint spectroscopic and theoretical study, we demonstrate that this behavior is also observed for di- and tetramethyl-substituted OTs,…
Energy transfer in diiodoBodipy-grafted upconversion nanohybrids.
2015
Steady-state and time-resolved emission studies on nanohybrids consisting of NaYF4:Yb,Er and a diiodo-substituted Bodipy (UCNP-IBDP) show that the Yb(3+) metastable state, formed after absorption of a near-infrared (NIR) photon, can decay via two competitive energy transfer processes: sensitization of IBDP after absorption of a second NIR photon and population of Er(3+) excited states.
Cobalt content of foods and diets in a Spanish population
1986
The WHO Expert Committee on Food Contaminants has pointed out the need of determining the content of foods in trace elements in order to ascertain their contribution to the total intake of oligoelements through the diet. Since the contents in trace elements depend on the environmental features, it is necessary to carry out systematic determinations of trace elements in foods of local origin in order to know the exposure level of population. This work intends to study the cobalt contribution through the diet. The element intake is calculated from the cobalt content in raw foods after elimination of the non-eatable moiety by flame atomic absorption spectroscopy, after formation of a chelate w…
Considerations on the Advantages and Disadvantages of Romania's Accession to the European Union
2015
Abstract After nine years from Romania's accession to the European Union, the advantages are sustained with specific statistical markers, which could have been more positive if the effect of certain identified causes (reduced administrative ability, political instability, extended corruption, high tax evasion etc.) would have been diminished. Counterbalancing the benefits of the accession the opinion polls show the disadvantages. If a poll conducted four years prior to the accession showed that 66% of Romania's population considered that the accession to the European Union would produce positive effects, after six years from the accession things have reversed and 58% of Romanians considered…
Photodynamics of a Molecular Water-Soluble Nanocluster Identified as Au130(pMBA)50
2015
Photodynamics of a highly monodisperse sample of a water-soluble gold nanocluster tentatively identified as Au130(pMBA)50 (pMBA = p-mercaptobenzoic acid) was studied by mid-IR transient absorption spectroscopy with visible excitation. The observed long-lived excited states (>1 ns) indicate a molecular behavior of the cluster. By combining the transient absorption data with DFT calculation results the observed relaxation dynamics could be fully explained by identifying several relaxation processes involving singlet and triplet manifolds. The results indicate that the cluster may have interesting transient magnetic properties due to a long-lived triplet population.
On the origin of worries about modern health hazards: Experimental evidence for a conjoint influence of media reports and personality traits
2017
Objective: Worries about health threatening effects of potential health hazards of modern life (e.g. electric devices and pollution) represent a growing phenomenon in Western countries. Yet, little is known about the causes of this growing special case of affective risk perceptions termed Modern Health Worries (MHW). The purpose of this study is to examine a possible role of biased media reports in the formation of MHW. Design: In two experiments, we investigated whether typical television reports affect MHW. In Study 1, 130 participants were randomly assigned to a film on idiopathic environmental intolerance (IEI) or a control film about cystic fibrosis. In Study 2, 82 participants were ra…
Biochar from Waste Derived Fuels as Low-Cost Adsorbent for Waste Hydrocarbons
2020
Abstract The aim of this study is to prove technical feasibility of combined refuse derived fuel (RDF) torrefaction and oily wastewater treatment approach by using RDF derived biochar as a sorption media. Biochars prepared from refuse derived fuels in torrefaction, carbonization and pyrolysis modes were analysed as fuels and as hydrocarbon sorbents. Changes of elemental composition and properties of material during thermal treatment and subsequent washing process have been analysed. Experimental evaluation of sorption behaviour of toluene and diesel fuel on obtained biochar performed. Our results show that torrefaction/carbonization of RDF coupled with the subsequent washing of biochar is a…
Investigations of methyl lactate in the presence of reverse micelles by vibrational spectroscopy and circular dichroism
2012
Abstract The FT-IR and vibrational circular dichroism (VCD) spectra of ( S )- and -( R )-methyl lactate have been recorded for neat samples and at various concentrations in CCl 4 and DMSO solutions. These spectra are used to analyse the FT-IR and VCD spectra of methyl lactates in presence of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in CCl 4 , where the surfactant molecules are known to form reverse micelles. Some tendency of methyl lactate to interact with AOT micellar aggregates is observed, but not as well defined as previously observed for dimethyl tartrate in analogous circumstances. Besides, near infrared (NIR) absorption and VCD data have been obtained for most of the above system…
Rośliny naczyniowe jako bioindykatory stanu środowiska
2017
Dzięki coraz nowocześniejszym i powszechniej stosowanym metodom bioindykacji można dokonać precyzyjnej i stosunkowo wydajnej oceny stanu środowiska naturalnego oraz zmian w nim zachodzących.Wymiernym sposobem monitoringu przyrody są obserwacje reakcji żywych organizmów. Badania przeprowadza się głównie z użyciem stenobiontów, czyli taksonów o małej tolerancji na zmienność warunków środowiska. Grupę roślin oraz zwierząt wykorzystywanych w badaniach bioindykacyjnych nazywa się wskaźnikowymi.Bioindykacja znajduje zastosowanie w geologii poszukiwawczej do odnajdywania miejsc z możliwością pozyskania cennych kruszców oraz w ochronie środowiska do monitoringu stanu jego zanieczyszczenia. Na podst…