Oxygen and water are inhibitors of acyloin and benzoin condensations. An intermediate paramagnetic compund is formed in the benzoin condensation catalyzed with 3-benzyl-4-methyl thiazolium chloride, ...3,4-dimethyl thiazolium iodide, 3-benzyl-4,5-dimethyl thiazolium chloride, 3-methyl-4-phenyl thiazolium perchlorate and 3-methyl-4,5-diphenyl thiazolium perchlorate. The formation of benzoin in dimethyl sulphoxide, when the air oxygen is absent, is an irreversible reaction. The presence of hydrophobic solvent in the reaction medium provides more favourable conditions for benzoin condensation proceeding. The reaction mechanism is suggested.
The review article outlines the problems of training a modern teacher-philologist, teacher-researcher in the field of philology. The trends in the development of philological pedagogical education in ...Ukraine have been outlined: the implementation of a competency-based approach in the training of philologists, the activation of scientific research activities of future philologists, the structuring of the content of disciplines on an interdisciplinary basis, the discreteness of the structuring of the content taking into account the Concept of the New School, state standards of basic secondary education, specialised schools; innovativeness and pragmatism of practical training of philological specialists. It has been found that the identified trends indicate the orientation of managers of higher pedagogical education institutions, teachers to improve the quality of training of philological teachers, taking into account innovative changes in the system of basic secondary education, specialised schools. The prospects for improving philological pedagogical education at the legislative-normative and organisational-pedagogical levels have been substantiated.
Abstract
Layered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization ...arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe
2
-WSe
2
stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moiré excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe
2
-WSe
2
heterobilayer is consistent with joint contributions from radiatively decaying valley-direct interlayer excitons and phonon-assisted emission from momentum-indirect reservoirs that reside in spatially distinct regions of moiré supercells, whereas the heterotrilayer emission is entirely due to momentum-dark interlayer excitons of hybrid-layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi-layered semiconductor van der Waals heterostructures.
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