1,720,974 research outputs found
MOLECULAR BEAM DENSITY MEASUREMENT WITH CAVITY-ENHANCED ABSORPTION SPECTROSCOPY
Full text linkMolecular beams have played an important role in chemical physics research, and beam density is crucial in determining beam properties, reaction rate, and differential cross-section in chemical dynamic experiments. However, few results present the absolute molecular beam density at the moment. We set up an experimental setup that combines the supersonic molecule beam and cavity-enhanced method. The absorption spectrum of carbon monoxide in the beam is continuously recorded when the beam is passing the cavity and we have demonstrated that the absolute molecular beam density can be measured. The absorption spectrum of the CO R₃(0) transition in the beam is shown in figure 1, the beam density can be obtained by measuring the absorption spectrum at different pressures and correcting the effective absorption length. It is expected that with the laser-locked cavity-enhanced method beam density of other molecules, such as C₂H₂, H₂O, CH₄, etc., can be measured quantitatively, which is significant in the crossed molecular beam experiments. This also provides a new method for measuring reaction products in chemical dynamic experiments
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
Precision Spectroscopy Of Hd
Full text linkPrecision spectral measurement of simple molecules such as H and their isotopes is one of the important research fields of spectroscopy. Combined with accurate calculations, allows us to test the fundamental quantum chemistry theory and to determine the fundamental physical constants such as the proton-to-electron mass ratio. Here we present the Doppler-free spectroscopy measurements of first overtone transition of HD at a temperature as low as 10K, measured the saturated absorption spectrum of the first overtone transition of HD and observed the Doppler free spectral of R (2-0) for the first time. The line profile is different from the saturated absorption spectrum. We analyzed the line profile and it is expected to determine the transition frequency with 11 digits
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
TWO-PHOTON ABSORPTION SPECTROSCOPY OF A ¹³CO₂ VIBRATIONAL TRANSITION
No full textTwo-photon absorption spectroscopy is an ideal method for precision measurements of molecular energy levels and trace gas concentration. We report a two- photon absorption of the Q(36) rovibrational transition of ¹³CO₂, measured by cavity- enhanced absorption spectroscopy (CEAS) at λ = 2.8 µm. The high signal-to-noise ratio of two-photon absorption spectra was obtained by optical locking of a narrow-linewidth mid-infrared laser to a high finesse cavity. One longitudinal mode of the cavity was shifted to scan the frequency, calibrated by an optical frequency comb. We studied the properties of the two-photon absorption spectrum. It is expected that this method can be applied in the field of molecular frequency reference and high-sensitivity detection
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
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
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