1,720,984 research outputs found
Ferroelectric nanoparticles in low refractive index liquid crystals for strong electro-optic response
No full textFunctional materials based on ferroelectric, inorganic nanoparticles, and low refractive index nematic liquid crystals show strong induced birefringence and dielectric anisotropy. Birefringence can increase by a factor of 2 and dielectric anisotropy by a factor of 3 as compared with nominally pure liquid crystals. The enhancement of the electro-optic performance is higher in liquid crystals with Sn2P2S6 (SPS) nanoparticles than with BaTiO3 nanoparticles. The shape and size distribution of both types of ferroelectric particles were characterized using atomic force microscopy. The average size of SPS nanoparticles was 45 nm and of BaTiO3 nanoparticles was 20 nm
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
The effect of the size of BaTiO<sub>3</sub> nanoparticles on the electro-optic properties of nematic liquid crystals
No full textThe size, size distribution and shape of ferroelectric BaTiO3 nanoparticles were determined using three different imaging techniques. The nanoparticles fabricated by milling microcrystals were found to have sizes of 12 ± 3 nm, 15 ± 3 nm and 18 ± 3 nm. Liquid crystal suspensions with 1% concentration of nanoparticles were prepared and their dielectric and optical anisotropy were measured. It is shown that the largest particles lead to the strongest enhancement of dielectric and optical anisotropy, as compared with undoped liquid crystals
Correlation of microstructural properties with thermoelectric performance of Bi0.Sb1.Te3 film fabricated by electroplating
No full textMicro and nanotechnologies for thermoelectric generators
No full textThis paper reviews the principles of thermoelectric energy harvesters and discusses the development of a new type of nanostructured thermoelectric generator, fabricated by combining silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Ion-track etched polyimide nanotemplates (30-100nm pore diameters) are used to grow Bi2Te3 nanowires by electroplating. Microstructural and thermoelectric properties of Bi2Te3 thin electroplated film are reported
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
Electrodeposition of thermoelectric materials
No full textElectrodeposition can be used as a cost-effective, room temperature technique for the fabrication of thermoelectric materials, as opposed to more traditional methods, such as chemical vapour deposition or molecular beam epitaxy, that require high temperatures and vacuum conditions. This chapter deals with understanding how electrodeposition can be applied as a technique, reviewing recent developments in its use in the deposition of thermoelectric materials, and exploring the use of additives and dopants during the deposition process in order to enhance the thermoelectric properties of the material. Results are presented to show how a surfactant, sodium lignosulfonate, can be added to an electrolyte in order to produce levelled and compact Bi2Te3 thin films with a preferred crystallographic orientation, thought to offer improved thermoelectric efficiency. Doping of ternary bismuth tellurium selenide semiconductor n-type thermoelectric deposits with small fractions of copper can be used to achieve a reduced crystallite size and dramatic enhancements in thermoelectric performance
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
Nanostructured thermoelectric generator for energy harvesting
No full textThis paper presents the development processes towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30nm to 120 nm were fabricated. Preliminary results for Bi2Te3 nanowires (50 and 120 nm diameter) electroplated into polycarbonate ion-track commercial membranes are presented. Bi2Te3 nanowires of R ̄ 3m structure, with preferential orientation in the (015) and (110) crystallographic plans with nearly stoichiometric composition were electroplated. The fine-grained observed microstructure (6-10 nm) and (110) crystalline orientation appear extremely promising for improving thermoelectric material properties
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