1,721,132 research outputs found
New hydrated phases of potassium orthovanadate: K₃(VO₄)(H₂O)₀.₅₆ and K₃(VO₄)(H₂O)₄
Get PDFSingle crystals of the hydrated potassium orthovanadate phases K₃(VO₄)·0.56H₂O, tripotassium orthovanadate 0.56-hydrate, and K₃(VO₄)·4H₂O, tripotassium orthovanadate tetrahydrate, were isolated during the processing of products obtained under hydroflux conditions. The asymmetric unit of K₃(VO₄)(H₂O)₀.₅₆ (space group P1, Z = 12) comprises six formula units of K₃(VO₄) and five water molecules of crystallization. The complex crystal structure is made up of isolated [VO4]³⁻ tetrahedra connected via K+ cations exhibiting coordination numbers between 6 and 8. The structure is consolidated by the formation of a finite hydrogen-bonded network between the water molecules and [VO4]³⁻ tetrahedra. Two of the K+ cations are positionally disordered, and three of the water molecules of crystallization are occupationally and/or positionally disordered. The asymmetric unit of K₃(VO₄)(H₂O)₄ (space group Pmn21, Z = 2) comprises two K+ cations, one VV atom, three O atoms and two water molecules. The crystal structure is also made up from isolated [VO₄]³⁻ tetrahedra interlinked by K+ cations (coordination numbers 7 and 8). In comparison with the less-hydrated phase, the higher water content of this compound results in an infinite network of O—H⋯O hydrogen bonds between the water molecules and [VO₄]³⁻ tetrahedra
Si͡evernye t͡svi͡ety na ... god : sobranye Knigoizdatelʹstvom "Skorpīon."
No full textVol. for 1905 called: Si͡everynye t͡svi͡ety assirīĭskīe.Mode of access: Internet
Вирощування та спектроскопія нових лазерних кристалів Ca₁₀Yb₀.₃K₀.₁(VO₄)₇
Get PDFCa₁₀Yb₀.₃K₀.₁(VO₄)₇ single crystals have been grown for the first time. Absorption and luminescence spectra, luminescence decay kinetics of ²F ₅/₂ level for Yb³⁺ ion are investigated
Вирощування та спектроскопія нових лазерних кристалів Ca₁₀Yb₀.₃K₀.₁(VO₄)₇
No full textCa₁₀Yb₀.₃K₀.₁(VO₄)₇ single crystals have been grown for the first time. Absorption and luminescence spectra, luminescence decay kinetics of ²F ₅/₂ level for Yb³⁺ ion are investigated
Вирощування та спектроскопія нових лазерних кристалів Ca₁₀Yb₀.₃K₀.₁(VO₄)₇
No full textCa₁₀Yb₀.₃K₀.₁(VO₄)₇ single crystals have been grown for the first time. Absorption and luminescence spectra, luminescence decay kinetics of ²F ₅/₂ level for Yb³⁺ ion are investigated
DFT Studies and Experiments on Biocatalytic Centers Structure, Vibrations, and Core Excitations of the K[VO O 2 Hheida] Complex
No full textGeometric and electronic properties of the K[VO(O2)Hheida] complex, which serves as a functional model for vanadium haloperoxidase enzymes, as well as of the molecular ions (VO(O2)Hheida)− and (VO(O)Hheida)− are evaluated using density-functional theory (DFT). Theoretical results of equilibrium structures, vibrational excitations, oxygen 1s core ionization and excitation are compared with measured data. The theoretical equilibrium structure of the K[VO(O2)Hheida] complex agrees quite well with the corresponding molecular structure in crystalline K[VO(O2)Hheida]·2(H2O) and differs only a little from that of the (VO(O2)Hheida)− ion. The potassium appears in the K[VO(O2)Hheida] complex as a positive K+ species binding only electrostatically with no orbital hybridization to the (VO(O2)Hheida)− part, which is also obvious from the respective orbital analyses and densities-of-states. The vibrational modes of peroxo and vanadyl oxygen in K[VO(O2)Hheida] are strongly coupled, and the calculated excitation energies can explain details of the experimental infrared and Raman spectra. The theoretical O 1s core ionization potentials (IP) vary between the different oxygen species and are consistent with results from X-ray photoemission (XPS). Theoretical O 1s core excitation spectra are confirmed by results from O K-edge NEXAFS measurements for crystalline K[VO(O2)Hheida]·2(H2O) under oxygen and helium pressure. The difference between the two experimental spectra can be explained by the presence of oxygen-deficient species based on the theoretical findings for the (VO(O)Hheida)− species
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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