1,720,981 research outputs found
Structure of Monolayers of Copper Tetra-(3-nitro-5-tert-butyl)-Phthalocyanine at the Air-water Interface.
No full textThe structure of floating layers of soluble copper tetra-(3-nitro-5-tert-butyl)-phthalocyanine (CuPc*) is studied through surface pressure-area (π-A) isotherms measured at various initial surface concentrations (N0) of CuPc*. In the gaseous layers, the CuPc* molecules are surrounded by a hydration sphere. Condensation of the layers under compression results in an increase in the tilt angle of the CuPc* molecules relative to the air-water interface. Though it is accompanied by a loss of weakly bound water, an inner part of the hydration sphere sustains compression and enters the condensed layers. Depending on the N0 and π values, the molecular tilt angle ranges from 30 to 90° indicating the phase states of the β-, α-, and x-types. The different nature of the bilayers formed through compression of the rare monolayers and through spreading of large amounts of CuPc* is stated
Sorption of amines by the Langmuir-Blodgett films of soluble Cobalt phthalocyanines: evidence for the supramolecular mechanism
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Supramolecular Approach to develop resistive chemical sensors of charged and neutral analytes
No full text"Some features of the molecular assembly of copper porphyrazines.”
No full textFloating layers and Langmuir-Blodgett (LB) films of copper porphyrazine (CuPaz) and its tetra-tert-butyl-substituted homologue (CuPaz') are studied. Contrary to phthalocyanines, the monolayer phase in the porphyrazine layers is metastable and transforms directly into the tetralayer one under moderate compression. In diffraction patterns and electronic spectra of the LB films, supramolecular peaks indicating collectivizing of the molecular electron density in direction perpendicular to the main axis of the macrocycle are found. The data obtained indicate the prismatic 3-D supermolecule to be the simplest structural unit of the porphyrazine assembly
Sorption of amines by the Langmuir-Blodgett films of soluble cobalt phthalocyanines: evidence for the supramolecular mechanisms
Full text linkBy means of microgravimetry, UV–Vis spectroscopy and optic microscopy, sorption of pyridine, primary aliphatic amines and benzylamine
by the Langmuir–Blodgett (LB) films of tetra-4-tert-butyl- and tetra-(3-nitro-5-tert-butyl)-substituted cobalt phthalocyanines (CoPc’ and
CoPc*, respectively) was studied over a broad concentration range. In general, sorption occurs as stepwise intercalation of the sorbate
molecules into the supramolecular 3D structure of the phthalocyanine assembly followed by formation of the donor–acceptor complexes.
Both intercalation depth and stoichiometry of the complexes are determined by the molecular structure of amines. The supramolecular factor
allows discrimination between amines in air but not in aqueous solutions because of concurrent intercalation of water
Variations on the Author
Full text link“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
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