Search results for "element"
showing 10 items of 13601 documents
Ligand-Centred Fluorescence and Electronic Relaxation Cascade at Vibrational Time Scales in Transition-Metal Complexes
2015
Using femtosecond-resolved photoluminescence up-conversion, we report the observation of the fluorescence of the high-lying ligand-centered (LC) electronic state upon 266 nm excitation of an iridium complex, Ir(ppy)(3), with a lifetime of 70 +/- 10 fs. It is accompanied by a simultaneous emission of all lower-lying electronic states, except the lowest triplet metal-to-ligand charge-transfer ((MLCT)-M-3) state that shows a rise on the same time scale. Thus, we observe the departure, the intermediate steps, and the arrival of the relaxation cascade spanning similar to 1.6 eV from the (LC)-L-1 state to the lowest 3MLCT state, which then yields the long-lived luminescence of the molecule. This …
Reproducibility of irritant patch test reactions to sodium lauryl sulfate in a double-blind placebo-controlled randomized study using clinical scorin…
1999
Reading of doubtful patch test reactions can be improved by comparing them to defined negative, allergic and irritant controls. For the latter, an irritant patch test is needed that gives sufficiently reproducible results. In our double-blind, placebo-controlled. randomized study, we have analysed the synchronous reproducibility of patch tests with 0%, 0.0625%, 0.125%, 0.25%, 0.5% and 1.0% sodium lauryl sulfate (SLS). Tests and readings were done according to ESCD guidelines. 139 patients (75 women, 64 men) 18 to 77 years old were tested. The % of positive patients as well as the % of reproducible positive reactions increased with rising concentrations of SLS to a maximum of approximately 9…
Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence.
2017
A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy–fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group assistance and chemodifferentiation.
Raman spectroscopy of glycolic acid complexes with N2
2019
High overtone excitation induced conformational isomerization of glycolic acid – nitrogen complex in an argon matrix was investigated by Raman spectroscopy. The interaction between glycolic acid and nitrogen change the green light (532 nm) induced isomerization processes compared to non-complexed glycolic acid. The 180° rotation around of the Csingle bondC bond and stabilization of carboxyl Odouble bondCsingle bondOsingle bondH dihedral angle to trans position were the main conformational changes observed in the complex of the lowest energy conformer and nitrogen. Interestingly, only one stable light-induced conformational product was observed, which isomerises back to the lowest energy con…
The Syntheses and Vibrational Spectra of 16 O- and 18 O-Enriched cis -MO2 (M=Mo, W) Complexes
2018
Mācīšanās darbavietā Solvay Business Services Latvia
2019
Maģistra darba „Mācīšanās darbavietā Solvay Business Services Latvia” autore ir Lāsma Saliņa. Darba apjoms ir 81 lappuses. Tajā ir izmantotas 5 tabulas; 30 attēli; 62 literatūras avoti un 5 pielikumi. Šī darba mērķis ir izpētīt, kā Solvay Business Services Latvia (turpmāk tekstā- SBS Latvia) darbinieki uztver mācīšanos darbavietā un kādas ir viņu vajadzības šajā jautājumā. Darbam izvirzīti šādi uzdevumi: 1. Analizēt teoriju atbilstoši izvēlētajai tēmai un sagatavot analīzes rezultātu pārskatu; 2. Veikt uzņēmuma darbinieku aptauju un interviju; 3. Apkopot, analizēt un raksturot iestādē veikto apsekojumu rezultātus; 4. Izdarīt secinājumus. Lai varētu izvērtēt mācīšanos darbavietā tika izstrād…
Exploration of jet substructure using iterative declustering in pp and Pb–Pb collisions at LHC energies
2020
The ALICE collaboration at the CERN LHC reports novel measurements of jet substructure in pp collisions at $\sqrt{s}$= 7 TeV and central Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV. Jet substructure of track-based jets is explored via iterative declustering and grooming techniques. We present the measurement of the momentum sharing of two-prong substructure exposed via grooming, the $z_{\rm{g}}$, and its dependence on the opening angle, in both pp and Pb-Pb collisions. We also present the first measurement of the distribution of the number of branches obtained in the iterative declustering of the jet, which is interpreted as the number of its hard splittings. In Pb-Pb collisions, we…
El juego popular y tradicional en la historia de la educación española contemporánea
2020
Popular and traditional play is part of the cultural identity and intangible heritage of a society. As such, with the passage of time, these have been transmitted and known by different generations who have been able to learn the different cultural codes and socialize playing the same games as their ancestors. Thus, we can affirm that these games are part of the curriculum that societies have bequeathed to the youngest. In this article we will make a tour of the main claims and uses that the pedagogical discourses in Spain have been doing around the popular and traditional play as an educational element. Los juegos populares y tradicionales forman parte de la identidad cultural y del patrim…
Conformations and Energetics of Sulfur and Selenium Diimides
2003
The geometries and energetics of different conformations of sulfur and selenium diimides E(NR) 2 (E = S, Se; R = H, Me, 'Bu, C 6 H 3 Me 2 -2,6, SiMe 3 ) have been studied by using various ab initio and DFT molecular orbital techniques. The syn,syn conformation is found to be most stable for parent E(NH) 2 , but in general, the preferred molecular conformation for substituted chalcogen diimides is syn,anti. In the case of E(NH) 2 the present calculations further confirm that syn,syn and syn,anti conformations lie energetically close to each other. From the three different theoretical methods used, B3PW91/6.31G * proved to be the most suitable method for predicting the geometries of chalcogen…