Search results for "Effects"
showing 10 items of 2634 documents
Misinterpretation caused by 3D effects on 2D Electrical Resistivity Tomography: tests on simple models
2018
Summary The aim of this work is to evaluate the effects of 2D inversion of electrical resistivity data when in presence on 3D structures by testing synthetic and experimental models. Several numerical simulations have been calculated for different resistivity models and 2D datasets were extracted to study and quantify the effects of 2D inversion on 3D structures. Results have been compared with field texts carried out in quarrying sites. The main tests here presented simulates prism-shaped cavities with a square vertical section of 1 × 1 size and a variable lateral extension d, from 1 to infinity (this latter being a 2D tunnel model). Inversion of predicted data show that 2D tomography does…
Solvent Control in Electro-Organic Synthesis
2018
Exploiting the solvent control within electro-organic conversions is a far underestimated parameter in prep-scale electrolysis. The beneficial application in several transformations is outlined and in particular discussed for the dehydrogenative coupling of arenes and heteroarenes. This simple electrolytic strategy in fluorinated solvents allows the modulation of the substrate’s nucleophilicity and the stabilization of the intermediates as well as of the final product from over-oxidation.1 Introduction2 Solvent Effects in Kolbe Electrolysis and Anodic Fluorination3 Unique Solvent Effects of 1,1,1,3,3,3-Hexafluoropropan-2-ol (HFIP)4 Anodic Dehydrogenative Coupling Reactions with Use of HFIP …
Effects of pulsed electromagnetic fields on cognitive processes - a pilot study on pulsed field interference with cognitive regeneration.
2004
Background – Due to the ubiquitous use of cellular phones much has been speculated on secondary effects of electromagnetic irradiation emitted by those. Additionally, several studies have reported vegetative alterations as well as effects on the neuronal and molecular levels in humans. Here, using a psycho–physiological test paradigm, we examined effects of exposure to pulsed electromagnetic fields on cognitive performance. Materials and methods – In 11 volunteers, we tested cognitive processing under field exposure (GSM standard) and under field-free conditions. To examine the hypothesized effect of pulsed fields, we applied an auditory discrimination task and determined the participant's …
Besteht eine Beeinträchtigung der ZNS-Aktivität durch gepulste elektromagnetische Felder? - Do Pulsed Electromagnetic Fields Impair CNS Activity?
2001
In the present pilot study we examined the effects of electromagnetic fields on the biological organism. The study was prompted by discussions on the possible effects on the nervous system and cognitive processes of fields produced by mobile phones. The experiments were performed in an electrophysiological laboratory. Eleven volunteers were exposed to pulsed electromagnetic fields (GSM standard). The psychophysiological method of assessing the order threshold (Ordnungsschwelle = OS) was used to examine cognitive performance. Under the test conditions, nine of the subjects showed a loss of mental regeneration, as reflected by an increase in the OS, in comparison with the field-free situation…
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 …
Space Charge and Carrier Trapping Effects on the Transient Photocurrents of Organic Materials Using the Time-of-Flight Technique
2007
We apply the time-of-flight (TOF) technique to study space charge and carrier trapping effects in the organic materials N,N'-diphenyl-N,N'-bis(3- methylphenyl)-1,1-biphenyl-4,4'-diamine (TPD) and tris(8-hydroxyquinolato) aluminum (Alq3). This is carried out by changing the applied electric field, the laser pulse intensity, and the repetition rate together with environmental conditions in air or in vacuum. We report for the first time, to the best of our knowledge, a clearly nondispersive electron transport in TPD due to the absence of deep traps. Conversely, Alq3 exhibits a dispersive electron transport. However, this can be partially recovered by leaving the sample in high vacuum for sever…
Most of the field/inductive substituent effect works through the bonds
2019
AbstractAn application of the quantum chemical modeling allowed to investigate the nature of the field/inductive substituent effect (SE). For this purpose, series of X-tert-butyl···tert-butane (TTX) complexes (where X = NMe2, NH2, OH, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, NO) were studied. A starting distance between central carbon atoms in substituted and unsubstituted fragments of TTX, dC1–C4, was the same as the distance C1–C4 in X-substituted bicyclo[2.2.2]octane (BCO), where the SE acts both via bonds and via space. A strength of interaction between substituted and unsubstituted components of TTX was described by deformation and interaction energies. The substituent …
Spin State and Ligand Dissociation in [CpCoL2] Complexes (L = PH3, H2C=CH2): A Computational Study
1999
International audience; The relative energies of [CpCoL] compounds (L = PH3, H2C=CH2) were calculated at the DFT/B3LYP level of theory. The triplet spin state was found to be favored over the singlet by between 33.0 and 21.0 kcal mol−1 for both fixed and optimized geometries. The basis set size was found to be important for the energy calculations, particularly when the energetics of ligand dissociation was examined. The role of the triplet spin state in facilitating the ligand dissociation process is discussed.
The role of travel motivations and social media use in consumer interactive behaviour: a uses and gratifications perspective
2020
This paper explores the influence of travel motivations and the gratification provided by social media in consumer stickiness to social media, intention to create user-generated content, and electronic word of mouth (eWOM) review adoption. The study follows a mixed-methods approach. First, a concept mapping study was undertaken to identify the main travel motivations and the gratifications provided by social media when consumers search for information on tourism destinations. A second study using structural equation modelling and SmartPLS 3.2.7 with a sample of 401 heavy users of social media showed the relationships between individual travel motivations and gratifications provided by socia…