1,720,973 research outputs found
Liquid nanodroplet formation through phase explosion mechanism in laser-irradiated metal targets
No full textSome quantitative aspects of laser-irradiated pure metals, while approaching phase explosion, are still not completely understood. Here, we develop a model that describes the main quantities regulating the liquid-vapor explosive phase transition and the expulsion of liquid nanodroplets that, by solidifying, give rise to nanoparticle formation. The model combines both a thermodynamics description of the explosive phase change and a Monte Carlo simulation of the randomly generated critical vapor bubbles. The calculation is performed on a set of seven metals (Al, Fe, Co, Ni, Cu, Ag, and Au) which are frequently used in pulsed laser ablation experiments. Our final predictions about the size distribution of the liquid nanodroplets and the number ratio of liquid/vapor ejected atoms are compared, whenever possible, with available molecular dynamics simulations and experimental data
Laser-Inducing Extreme Thermodynamic Conditions in Condensed Matter to Produce Nanomaterials for Catalysis and the Photocatalysis
No full textVaporization from the aluminum target surface, under nanosecond laser irradiation, was evaluated in the framework of the unsteady adiabatic expansion model, while the homogeneous nucleation of vapor bubbles in the metastable liquid (phase explosion) was simulated in the framework of the classical nucleation theory. The size distribution of the liquid nanodroplets produced in the phase explosion process was found to obey a power law in agreement with the few available experimental data when it is assumed that nanoparticles formation comes from solidification of liquid nanodroplets. Some experimental examples are reported to show that pulsed-laser deposition technique is able to synthesize nanoparticles in a single step with the required features for catalysis and photocatalysis applications
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
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
Low-energy X-ray spectroscopy with RGB-HD SiPMs coupled to CsI(Tl) scintillator
No full textThe continuous improvement of Silicon Photomultiplier (SiPM) characteristics opens new perspectives for the application of these detectors in middle to low energy X-ray scintillation light readout. Compared to traditional PET detectors this application poses an additional challenge because of the much lower number of photons generated in the scintillator. Many SiPM characteristics influence the energy resolution of the detected radiation, including Photon Detection Efficiency (PDE), primary noise and Excess Noise Factor (ENF). The most recent development of the RGB-HD SiPM technology at Fondazione Bruno Kessler (FBK, Italy) provides a PDE up to 40% at 550 nm while keeping the Dark Count Rate (DCR) below 500 kc.p.s./mm2. A low DCR value is fundamental in improving the energy resolution for soft X-rays. In this work we coupled a 1×1 mm2 RGB-HD SiPM to a 0.9×0.9×2 mm3 CsI(Tl) crystal allowing the detection of 55Fe 5.9 keV photons with an energy resolution of 39% FWHM. A 4×4 mm2 RGB-HD SiPM with a 3×3×5 mm3 CsI(Tl) was used for the readout of a 57Co source (6.4 keV, 14.4 keV and 122 keV) in order to prove the dynamic range of the system. The energy resolution of these three peaks shows different trends with respect to the SiPM bias and to the signal integration time. This is related to the fact that SiPM parameters such as PDE, DCR and ENF, and readout parameters such as integration time, become more or less relevant depending on the energy of the primary photon
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
