1,721,061 research outputs found
ODOR PROPERTIES OF SOME TETRAHYDROPYRANYL ETHERS
No full textSeveral tetrahydropyranyl derivatives of phenols and alcohols have been prepared with the aim of reproducing the floral note of hydroxycitronellal in compounds of easier and cheaper synthesis. Some of the derivatives, particularly those prepared from cis-4-methylcyclohexanol and p-alkylphenols, present a pleasant floral character as the main note and could be used as detergent additives and in other products of pH above neutrality. This research also represents a contribution toward the understanding of the relationships between molecular structure and the odor of muguet
Tuning and hybridization of surface phonon polaritons in α-MoO3 based metamaterials.
Full text linkWe propose an effective medium approach to tune and control surface phonon polariton dispersion relations along the three main crystallographic directions of α-phase molybdenum trioxide. We show that a metamaterial consisting of subwavelength air inclusions into the α-MoO3 matrix displays new absorption modes producing a split of the Reststrahlen bands of the crystal and creating new branches of phonon polaritons. In particular, we report hybridization of bulk and surface polariton modes by tailoring metamaterials' structural parameters. Theoretical predictions obtained with the effective medium approach are validated by full-field electromagnetic simulations using finite difference time domain method. Our study sheds light on the use of effective medium theory for modeling and predicting wavefront polaritons. Our simple yet effective approach could potentially enable different functionalities for hyperbolic infrared metasurface devices and circuits on a single compact platform for on-chip infrared photonics
EFFECT OF SULFUR SUBSTITUTION ON THE FLORAL ODOR OF TETRAHYDROPYRANYL AND TETRAHYDROFURANYL ETHERS
No full textSulfur-containing analogues of tetrahydropyranyl and tetrahydrofuranyl derivatives of selected alcohols and phenols have been prepared and their odor properties evaluated. The compounds include derivatives in which either one or both of the oxygen atoms had been replaced with sulfur. Derivatives with two sulfur atoms do not exhibit pleasant odors; those with an endocyclic oxygen and an exocyclic sulfur generally exhibit green notes. The floral character is found only in a few derivatives with an endocyclic sulfur and an exocyclic oxygen
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
INFLUENCE OF THE REGIOCHEMISTRY AND STEREOCHEMISTRY ON THE FLORAL ODOR OF THP AND THF ETHERS
No full textThe relationships between chemical structure and the odor of white flowers in a new series of tetrahydropyranyl and tetrahydrofuranyl derivatives of substituted cyclohexanols and phenols was investigated, with particular reference to the stereochemistry of the odorants. Several of these compounds exhibit a pleasant floral odor, two of them being very similar in their odor profiles to hydroxycitronellal, taken as a reference for the odor of white flowers. They represent interesting alternatives to the currently used additives for cosmetics and detergents
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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