1,723,057 research outputs found
Si(Li) X-ray astronomical spectroscopy
Get PDFThe general considerations involved in the choice of Si(Li) as a non-dispersive spectrometer for X-ray astronomy are discussed. In particular, its adaptation to HEAO-B is described as an example of the space-borne application of Si(Li) technology
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
Large-scale detector testing for the GAPS Si(Li) Tracker
Get PDFLithium-drifted silicon [Si(Li)] has been used for decades as an ionizing
radiation detector in nuclear, particle, and astrophysical experiments, though
such detectors have frequently been limited to small sizes (few cm) and
cryogenic operating temperatures. The 10-cm-diameter Si(Li) detectors developed
for the General Antiparticle Spectrometer (GAPS) balloon-borne dark matter
experiment are novel particularly for their requirements of low cost, large
sensitive area (~10 m for the full 1440-detector array), high temperatures
(near -40C), and energy resolution below 4 keV FWHM for 20--100-keV
x-rays. Previous works have discussed the manufacturing, passivation, and
small-scale testing of prototype GAPS Si(Li) detectors. Here we show for the
first time the results from detailed characterization of over 1100 flight
detectors, illustrating the consistent intrinsic low-noise performance of a
large sample of GAPS detectors. This work demonstrates the feasibility of
large-area and low-cost Si(Li) detector arrays for next-generation astrophysics
and nuclear physics applications.Comment: Updated to version accepted in IEEE Trans Nucl Sci. Minor changes to
text, fixed plotting error on Fig. 5. Conclusions unchange
Pulse Shape Analysis Studies in Si(Li) Detector
Get PDFThis work presents developments in the nuclear radiation detection, which take advantage of fast digital electronics. Numerical algorithms, which analyze detector pulse shape, were tested. A method to discriminate between electrons and gamma radiation using pulse shape analysis was demonstrated. The analysis was done on the data taken with 207Bi source using a semiconductor Si(Li) detector. An algorithm to improve the timing resolution of the detection system was implemented. Software code to simulate the pulse shape generation process, for electrons and gamma radiation, in a Si(Li) detector was developed. Advantages of the applications of digital electronics in nuclear spectroscopy are discussed
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Si(Li) detectors with thin dead layers for low energy x-ray detection
Get PDFRegions of incomplete charge collection, or dead layers'', are compared for Si(Li) detectors fabricated with Au and Pd entrance window electrodes. The dead layers were measured by characterizing the detector spectral response to x-ray energies above and below the Si K{alpha} absorption edge. It was found that Si(Li) detectors with Pd electrodes exhibit consistently thinner effective Si dead layers than those with Au electrodes. Furthermore, it is demonstrated that the minimum thickness required for low resistivity Pd electrodes is thinner than that required for low resistivity Au electrodes, which further reduces the signal attenuation in Pd/Si(Li) detectors. A model, based on Pd compensation of oxygen vacancies in the SiO{sub 2} at the entrance window Si(Li) surface, is proposed to explain the observed differences in detector dead layer thickness. Electrode structures for optimum Si(Li) detector performance at low x-ray energies are discussed. 18 refs., 8 figs., 1 tab
Si (Li）軟X線検出器の管理について
No full text1. はじめに / 2. Si (Li）軟X線検出器について / 3. Si (Li）軟X線測定装置と設置されている検出器 / 4. 補給する液体窒素について / 5. Si (Li）軟X線検出器の液体窒素補給業務につい
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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