Search results for "element"
showing 10 items of 13601 documents
Preparation and Characterization of P2 BCh Ring Systems (Ch=S, Se) and Their Reactivity with N-Heterocyclic Carbenes
2018
Four-membered rings with a P2BCh core (Ch = S, Se) have been synthesized via reaction of phosphinidene chalcogenide (Ar*P=Ch) and phosphaborene (Mes*P=BNR2). The mechanistic pathways towards these rings are explained by detailed computational work that confirmed the preference for the formation of P–P, not P–B, bonded systems, which seems counterintuitive given that both phosphorus atoms contain bulky ligands. The reactivity of the newly synthesized heterocycles, as well as that of the known (RPCh)n rings (n = 2, 3), was probed by the addition of Nheterocyclic carbenes, which revealed that all investigated compounds can act as sources of low-coordinate phosphorus species. peerReviewed
On an Amendment of the Morality of a Physicist’s Professional Actions. A “new” Element of Inculturation of Christianity into a Scientific-Technologic…
2020
O zmianie moralności profesjonalnych działań fizyka. Nowy element inkulturacji chrześcijaństwa w cywilizację naukowo-technologiczną
 Fizycy są zobowiązani, zgodnie z ustalonymi metodami i standardami fizyki, do myślenia i działania w ramach epistemologicznych, na co głęboki wpływ miał I. Kant. Klimat epistemologiczny, w którym się znajdują, sprzeciwia się epistemologicznemu klimatowi realizmu naturalnego, a tym samym epistemologicznemu klimatowi Objawienia chrześcijańskiego, kiedy mówi ono o naszym świecie. Ten kontrast niszczy wewnętrzną harmonię świata umysłowego każdego fizyka w takim stopniu, w jakim zależy on od jego ogólnego sposobu myślenia, a także od jego pracy zawodowej. Sytu…
Dynamics of particulate major and trace elements in the lower reaches of the Daugava River and adjacent area of the Gulf of Riga (Baltic Sea).
2004
Suspended particulate matter (SPM) was collected in the freshwater-seawater mixing zone in the lower reaches of the Daugava River (Latvia) and adjacent marine area, during five cruises in 1998-2001. The study focused on biogeochemical phase exchange processes. SPM in the freshwater was found to be mainly allochthonous with a high content of organic matter, Mn and sorbed phosphate. Property-salinity plots suggested flocculation of humic-Fe complexes across the salinity gradient. The variability of sorbed phosphate was related to particulate Fe, although no dependence on pH and ionic strength was observed. The Mn contents of SPM mainly follow conservative mixing, but there are also indication…
Ultra-conserved elements provide insights to the biogeographic patterns of three benthic macroinvertebrate species in the Baltic Sea
2022
The Baltic Sea, with its steep salinity gradient, high water retention time, and relatively young age, represents a marginal ecosystem between marine and freshwater extremes. Due to differing invasion history and dispersal capabilities of Baltic species, there are large differences in species distributions, species-specific genetic structure and variation, and edge populations that may represent both a subset of the original population, as well as unique genetic lineages. We used a phylogenomic approach to investigate relationships between populations of three benthic macroinvertebrate species: Pygospio elegans, Corophium volutator, and Mya arenaria, providing new insight into evolutionary …
Baltijas valstu un Somijas tūrisma galamērķa tēla elementi Krievijas auditorijā
2022
Tēlam ir ļoti liela nozīme ceļojuma galamērķa veiksmīgā attīstībā, jo pozitīvs tēls palielina galamērķa atpazīstamību un ietekmē tūristu vēlmi apmeklēt šo galamērķi. Šī pētījuma mērķis ir izpētīt galamērķa tēlu veidojošos elementus, ko Krievijas ceļotāji veido un izplata par Baltijas valstīm (Igauniju, Latviju un Lietuvu) un Somiju. Šajā darbā tēls, tostarp tēla elementi tiek pētīti, izmantojot krievu tūristu atsauksmju, kas publicētas ar ceļošanu saistītās tīmekļa vietnēs, satura analīzi. Darbā tiek atklāti nozīmīgākie galamērķa tēla atribūti, tādi kā, kultūras un dabas resursi, atmosfēra, infrastruktūra, gastronomiskais piedāvājums un nakts dzīve, tīrība, drošība, vietējo iedzīvotāju vies…
Description of kraft cooking and oxygen–alkali delignification of bamboo by pulp and dissolving material analysis
2008
Abstract The oxygen delignification of two bamboo ( Bambusa procera ) kraft pulps with kappa numbers of 13.6 and 20.0 were studied under typical conditions. Based on detailed analysis data on both the kraft and oxygen-delignified pulps and the corresponding spent liquors (black liquors and oxygen stage effluents), three yield and four selectivity estimation methods, utilizing component material balances, were tested resulting in the value ranges 96.2–97.9% and 43.5–60.4%, respectively, for oxygen delignification process studied. The traditional selectivity using the viscosity and kappa number relation was 66.9–68.4%. The studied bamboo kraft pulps behaved typically as birch kraft pulps duri…
Solid-State Synthesis of “Bamboo-Like” and Straight Carbon Nanotubes by Thermolysis of Hexa-peri-hexabenzocoronene–Cobalt Complexes
2006
Lowest triplet excited states of a novel heteroleptic iridium(III) complex and their role in the emission colour
2009
Abstract The [Ir(ppy-F 2 ) 2 Me 4 phen] +1 complex, where ppy-F 2 is 2-(2′,4′-fluorophenyl)pyridine and Me 4 phen is 3,4,7,8-tetramethyl-1,10-phenanthroline, has been theoretically investigated by means of DFT calculations. The molecular and electronic properties calculated for [Ir(ppy-F 2 ) 2 Me 4 phen] +1 are compared with those obtained for the simpler [Ir(ppy)(bpy)] +1 complex. The introduction of fluorine substituents in the ppy ligands and the use of phenanthroline instead of 2,2′-bipyridine as the diimine ligand increase the HOMO–LUMO energy gap and blue-shift the emission colour. The phenanthroline ligand causes the appearance of two nearly-degenerate LUMO orbitals of different symm…
Screening the bulk properties and reducibility of Fe-doped Mn2O3 from first principles calculations
2017
Abstract Manganese oxides, particularly Mn 2 O 3 , have demonstrated great potential for oxygen carrier materials in chemical looping applications. The application of these materials in the industrial scale is hindered by thermodynamic restrictions related to the reoxidation process. This disadvantage can be overcome by doping the oxide with a guest cation. Iron is one of the most promising dopants, but the atomic-level understanding of its effects on the properties of α-Mn 2 O 3 is incomplete. Herein, we report a systematic GGA+U study of the bulk properties and reducibility of Fe x Mn 2-x O 3 (0 ≤ x ≤ 2) as a function of Fe dopant concentration. In particular, we focus on a representative…
CoOx catalysts supported on alumina and alumina-baria: influence of the support on the cobalt species and their activity in NO reduction by C3H6 in l…
2003
Abstract CoO x catalysts (Co 1 and 3 wt.%) were prepared by incipient-wetness impregnation of the supports, Al 2 O 3 and Al 2 O 3 (80 wt.%)-BaO (20 wt.%), and calcined at 500 and 800 °C. The samples were characterized by X-ray diffraction (XRD) and BET techniques. H 2 -temperature programmed reduction (TPR) and UV-Vis diffuse reflectance spectroscopy (DRS) spectra were recorded with the aim to identify the different Co species formed. The presence of Co 2+ species tetrahedrally and octahedrally coordinated appears strongly influenced by the nature of the support and the cobalt content. Co 3 O 4 particles were detected after calcination at 500 °C, a successive treatment at 800 °C promotes th…